xref: /openbmc/u-boot/drivers/mtd/nand/raw/nand_base.c (revision 05512517)
1 /*
2  *  Overview:
3  *   This is the generic MTD driver for NAND flash devices. It should be
4  *   capable of working with almost all NAND chips currently available.
5  *
6  *	Additional technical information is available on
7  *	http://www.linux-mtd.infradead.org/doc/nand.html
8  *
9  *  Copyright (C) 2000 Steven J. Hill (sjhill@realitydiluted.com)
10  *		  2002-2006 Thomas Gleixner (tglx@linutronix.de)
11  *
12  *  Credits:
13  *	David Woodhouse for adding multichip support
14  *
15  *	Aleph One Ltd. and Toby Churchill Ltd. for supporting the
16  *	rework for 2K page size chips
17  *
18  *  TODO:
19  *	Enable cached programming for 2k page size chips
20  *	Check, if mtd->ecctype should be set to MTD_ECC_HW
21  *	if we have HW ECC support.
22  *	BBT table is not serialized, has to be fixed
23  *
24  * This program is free software; you can redistribute it and/or modify
25  * it under the terms of the GNU General Public License version 2 as
26  * published by the Free Software Foundation.
27  *
28  */
29 
30 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
31 #include <common.h>
32 #if CONFIG_IS_ENABLED(OF_CONTROL)
33 #include <fdtdec.h>
34 #endif
35 #include <malloc.h>
36 #include <watchdog.h>
37 #include <linux/err.h>
38 #include <linux/compat.h>
39 #include <linux/mtd/mtd.h>
40 #include <linux/mtd/rawnand.h>
41 #include <linux/mtd/nand_ecc.h>
42 #include <linux/mtd/nand_bch.h>
43 #ifdef CONFIG_MTD_PARTITIONS
44 #include <linux/mtd/partitions.h>
45 #endif
46 #include <asm/io.h>
47 #include <linux/errno.h>
48 
49 /* Define default oob placement schemes for large and small page devices */
50 #ifdef CONFIG_SYS_NAND_DRIVER_ECC_LAYOUT
51 static struct nand_ecclayout nand_oob_8 = {
52 	.eccbytes = 3,
53 	.eccpos = {0, 1, 2},
54 	.oobfree = {
55 		{.offset = 3,
56 		 .length = 2},
57 		{.offset = 6,
58 		 .length = 2} }
59 };
60 
61 static struct nand_ecclayout nand_oob_16 = {
62 	.eccbytes = 6,
63 	.eccpos = {0, 1, 2, 3, 6, 7},
64 	.oobfree = {
65 		{.offset = 8,
66 		 . length = 8} }
67 };
68 
69 static struct nand_ecclayout nand_oob_64 = {
70 	.eccbytes = 24,
71 	.eccpos = {
72 		   40, 41, 42, 43, 44, 45, 46, 47,
73 		   48, 49, 50, 51, 52, 53, 54, 55,
74 		   56, 57, 58, 59, 60, 61, 62, 63},
75 	.oobfree = {
76 		{.offset = 2,
77 		 .length = 38} }
78 };
79 
80 static struct nand_ecclayout nand_oob_128 = {
81 	.eccbytes = 48,
82 	.eccpos = {
83 		   80, 81, 82, 83, 84, 85, 86, 87,
84 		   88, 89, 90, 91, 92, 93, 94, 95,
85 		   96, 97, 98, 99, 100, 101, 102, 103,
86 		   104, 105, 106, 107, 108, 109, 110, 111,
87 		   112, 113, 114, 115, 116, 117, 118, 119,
88 		   120, 121, 122, 123, 124, 125, 126, 127},
89 	.oobfree = {
90 		{.offset = 2,
91 		 .length = 78} }
92 };
93 #endif
94 
95 static int nand_get_device(struct mtd_info *mtd, int new_state);
96 
97 static int nand_do_write_oob(struct mtd_info *mtd, loff_t to,
98 			     struct mtd_oob_ops *ops);
99 
100 /*
101  * For devices which display every fart in the system on a separate LED. Is
102  * compiled away when LED support is disabled.
103  */
104 DEFINE_LED_TRIGGER(nand_led_trigger);
105 
106 static int check_offs_len(struct mtd_info *mtd,
107 					loff_t ofs, uint64_t len)
108 {
109 	struct nand_chip *chip = mtd_to_nand(mtd);
110 	int ret = 0;
111 
112 	/* Start address must align on block boundary */
113 	if (ofs & ((1ULL << chip->phys_erase_shift) - 1)) {
114 		pr_debug("%s: unaligned address\n", __func__);
115 		ret = -EINVAL;
116 	}
117 
118 	/* Length must align on block boundary */
119 	if (len & ((1ULL << chip->phys_erase_shift) - 1)) {
120 		pr_debug("%s: length not block aligned\n", __func__);
121 		ret = -EINVAL;
122 	}
123 
124 	return ret;
125 }
126 
127 /**
128  * nand_release_device - [GENERIC] release chip
129  * @mtd: MTD device structure
130  *
131  * Release chip lock and wake up anyone waiting on the device.
132  */
133 static void nand_release_device(struct mtd_info *mtd)
134 {
135 	struct nand_chip *chip = mtd_to_nand(mtd);
136 
137 	/* De-select the NAND device */
138 	chip->select_chip(mtd, -1);
139 }
140 
141 /**
142  * nand_read_byte - [DEFAULT] read one byte from the chip
143  * @mtd: MTD device structure
144  *
145  * Default read function for 8bit buswidth
146  */
147 uint8_t nand_read_byte(struct mtd_info *mtd)
148 {
149 	struct nand_chip *chip = mtd_to_nand(mtd);
150 	return readb(chip->IO_ADDR_R);
151 }
152 
153 /**
154  * nand_read_byte16 - [DEFAULT] read one byte endianness aware from the chip
155  * @mtd: MTD device structure
156  *
157  * Default read function for 16bit buswidth with endianness conversion.
158  *
159  */
160 static uint8_t nand_read_byte16(struct mtd_info *mtd)
161 {
162 	struct nand_chip *chip = mtd_to_nand(mtd);
163 	return (uint8_t) cpu_to_le16(readw(chip->IO_ADDR_R));
164 }
165 
166 /**
167  * nand_read_word - [DEFAULT] read one word from the chip
168  * @mtd: MTD device structure
169  *
170  * Default read function for 16bit buswidth without endianness conversion.
171  */
172 static u16 nand_read_word(struct mtd_info *mtd)
173 {
174 	struct nand_chip *chip = mtd_to_nand(mtd);
175 	return readw(chip->IO_ADDR_R);
176 }
177 
178 /**
179  * nand_select_chip - [DEFAULT] control CE line
180  * @mtd: MTD device structure
181  * @chipnr: chipnumber to select, -1 for deselect
182  *
183  * Default select function for 1 chip devices.
184  */
185 static void nand_select_chip(struct mtd_info *mtd, int chipnr)
186 {
187 	struct nand_chip *chip = mtd_to_nand(mtd);
188 
189 	switch (chipnr) {
190 	case -1:
191 		chip->cmd_ctrl(mtd, NAND_CMD_NONE, 0 | NAND_CTRL_CHANGE);
192 		break;
193 	case 0:
194 		break;
195 
196 	default:
197 		BUG();
198 	}
199 }
200 
201 /**
202  * nand_write_byte - [DEFAULT] write single byte to chip
203  * @mtd: MTD device structure
204  * @byte: value to write
205  *
206  * Default function to write a byte to I/O[7:0]
207  */
208 static void nand_write_byte(struct mtd_info *mtd, uint8_t byte)
209 {
210 	struct nand_chip *chip = mtd_to_nand(mtd);
211 
212 	chip->write_buf(mtd, &byte, 1);
213 }
214 
215 /**
216  * nand_write_byte16 - [DEFAULT] write single byte to a chip with width 16
217  * @mtd: MTD device structure
218  * @byte: value to write
219  *
220  * Default function to write a byte to I/O[7:0] on a 16-bit wide chip.
221  */
222 static void nand_write_byte16(struct mtd_info *mtd, uint8_t byte)
223 {
224 	struct nand_chip *chip = mtd_to_nand(mtd);
225 	uint16_t word = byte;
226 
227 	/*
228 	 * It's not entirely clear what should happen to I/O[15:8] when writing
229 	 * a byte. The ONFi spec (Revision 3.1; 2012-09-19, Section 2.16) reads:
230 	 *
231 	 *    When the host supports a 16-bit bus width, only data is
232 	 *    transferred at the 16-bit width. All address and command line
233 	 *    transfers shall use only the lower 8-bits of the data bus. During
234 	 *    command transfers, the host may place any value on the upper
235 	 *    8-bits of the data bus. During address transfers, the host shall
236 	 *    set the upper 8-bits of the data bus to 00h.
237 	 *
238 	 * One user of the write_byte callback is nand_onfi_set_features. The
239 	 * four parameters are specified to be written to I/O[7:0], but this is
240 	 * neither an address nor a command transfer. Let's assume a 0 on the
241 	 * upper I/O lines is OK.
242 	 */
243 	chip->write_buf(mtd, (uint8_t *)&word, 2);
244 }
245 
246 static void iowrite8_rep(void *addr, const uint8_t *buf, int len)
247 {
248 	int i;
249 
250 	for (i = 0; i < len; i++)
251 		writeb(buf[i], addr);
252 }
253 static void ioread8_rep(void *addr, uint8_t *buf, int len)
254 {
255 	int i;
256 
257 	for (i = 0; i < len; i++)
258 		buf[i] = readb(addr);
259 }
260 
261 static void ioread16_rep(void *addr, void *buf, int len)
262 {
263 	int i;
264  	u16 *p = (u16 *) buf;
265 
266 	for (i = 0; i < len; i++)
267 		p[i] = readw(addr);
268 }
269 
270 static void iowrite16_rep(void *addr, void *buf, int len)
271 {
272 	int i;
273         u16 *p = (u16 *) buf;
274 
275         for (i = 0; i < len; i++)
276                 writew(p[i], addr);
277 }
278 
279 /**
280  * nand_write_buf - [DEFAULT] write buffer to chip
281  * @mtd: MTD device structure
282  * @buf: data buffer
283  * @len: number of bytes to write
284  *
285  * Default write function for 8bit buswidth.
286  */
287 void nand_write_buf(struct mtd_info *mtd, const uint8_t *buf, int len)
288 {
289 	struct nand_chip *chip = mtd_to_nand(mtd);
290 
291 	iowrite8_rep(chip->IO_ADDR_W, buf, len);
292 }
293 
294 /**
295  * nand_read_buf - [DEFAULT] read chip data into buffer
296  * @mtd: MTD device structure
297  * @buf: buffer to store date
298  * @len: number of bytes to read
299  *
300  * Default read function for 8bit buswidth.
301  */
302 void nand_read_buf(struct mtd_info *mtd, uint8_t *buf, int len)
303 {
304 	struct nand_chip *chip = mtd_to_nand(mtd);
305 
306 	ioread8_rep(chip->IO_ADDR_R, buf, len);
307 }
308 
309 /**
310  * nand_write_buf16 - [DEFAULT] write buffer to chip
311  * @mtd: MTD device structure
312  * @buf: data buffer
313  * @len: number of bytes to write
314  *
315  * Default write function for 16bit buswidth.
316  */
317 void nand_write_buf16(struct mtd_info *mtd, const uint8_t *buf, int len)
318 {
319 	struct nand_chip *chip = mtd_to_nand(mtd);
320 	u16 *p = (u16 *) buf;
321 
322 	iowrite16_rep(chip->IO_ADDR_W, p, len >> 1);
323 }
324 
325 /**
326  * nand_read_buf16 - [DEFAULT] read chip data into buffer
327  * @mtd: MTD device structure
328  * @buf: buffer to store date
329  * @len: number of bytes to read
330  *
331  * Default read function for 16bit buswidth.
332  */
333 void nand_read_buf16(struct mtd_info *mtd, uint8_t *buf, int len)
334 {
335 	struct nand_chip *chip = mtd_to_nand(mtd);
336 	u16 *p = (u16 *) buf;
337 
338 	ioread16_rep(chip->IO_ADDR_R, p, len >> 1);
339 }
340 
341 /**
342  * nand_block_bad - [DEFAULT] Read bad block marker from the chip
343  * @mtd: MTD device structure
344  * @ofs: offset from device start
345  *
346  * Check, if the block is bad.
347  */
348 static int nand_block_bad(struct mtd_info *mtd, loff_t ofs)
349 {
350 	int page, res = 0, i = 0;
351 	struct nand_chip *chip = mtd_to_nand(mtd);
352 	u16 bad;
353 
354 	if (chip->bbt_options & NAND_BBT_SCANLASTPAGE)
355 		ofs += mtd->erasesize - mtd->writesize;
356 
357 	page = (int)(ofs >> chip->page_shift) & chip->pagemask;
358 
359 	do {
360 		if (chip->options & NAND_BUSWIDTH_16) {
361 			chip->cmdfunc(mtd, NAND_CMD_READOOB,
362 					chip->badblockpos & 0xFE, page);
363 			bad = cpu_to_le16(chip->read_word(mtd));
364 			if (chip->badblockpos & 0x1)
365 				bad >>= 8;
366 			else
367 				bad &= 0xFF;
368 		} else {
369 			chip->cmdfunc(mtd, NAND_CMD_READOOB, chip->badblockpos,
370 					page);
371 			bad = chip->read_byte(mtd);
372 		}
373 
374 		if (likely(chip->badblockbits == 8))
375 			res = bad != 0xFF;
376 		else
377 			res = hweight8(bad) < chip->badblockbits;
378 		ofs += mtd->writesize;
379 		page = (int)(ofs >> chip->page_shift) & chip->pagemask;
380 		i++;
381 	} while (!res && i < 2 && (chip->bbt_options & NAND_BBT_SCAN2NDPAGE));
382 
383 	return res;
384 }
385 
386 /**
387  * nand_default_block_markbad - [DEFAULT] mark a block bad via bad block marker
388  * @mtd: MTD device structure
389  * @ofs: offset from device start
390  *
391  * This is the default implementation, which can be overridden by a hardware
392  * specific driver. It provides the details for writing a bad block marker to a
393  * block.
394  */
395 static int nand_default_block_markbad(struct mtd_info *mtd, loff_t ofs)
396 {
397 	struct nand_chip *chip = mtd_to_nand(mtd);
398 	struct mtd_oob_ops ops;
399 	uint8_t buf[2] = { 0, 0 };
400 	int ret = 0, res, i = 0;
401 
402 	memset(&ops, 0, sizeof(ops));
403 	ops.oobbuf = buf;
404 	ops.ooboffs = chip->badblockpos;
405 	if (chip->options & NAND_BUSWIDTH_16) {
406 		ops.ooboffs &= ~0x01;
407 		ops.len = ops.ooblen = 2;
408 	} else {
409 		ops.len = ops.ooblen = 1;
410 	}
411 	ops.mode = MTD_OPS_PLACE_OOB;
412 
413 	/* Write to first/last page(s) if necessary */
414 	if (chip->bbt_options & NAND_BBT_SCANLASTPAGE)
415 		ofs += mtd->erasesize - mtd->writesize;
416 	do {
417 		res = nand_do_write_oob(mtd, ofs, &ops);
418 		if (!ret)
419 			ret = res;
420 
421 		i++;
422 		ofs += mtd->writesize;
423 	} while ((chip->bbt_options & NAND_BBT_SCAN2NDPAGE) && i < 2);
424 
425 	return ret;
426 }
427 
428 /**
429  * nand_block_markbad_lowlevel - mark a block bad
430  * @mtd: MTD device structure
431  * @ofs: offset from device start
432  *
433  * This function performs the generic NAND bad block marking steps (i.e., bad
434  * block table(s) and/or marker(s)). We only allow the hardware driver to
435  * specify how to write bad block markers to OOB (chip->block_markbad).
436  *
437  * We try operations in the following order:
438  *  (1) erase the affected block, to allow OOB marker to be written cleanly
439  *  (2) write bad block marker to OOB area of affected block (unless flag
440  *      NAND_BBT_NO_OOB_BBM is present)
441  *  (3) update the BBT
442  * Note that we retain the first error encountered in (2) or (3), finish the
443  * procedures, and dump the error in the end.
444 */
445 static int nand_block_markbad_lowlevel(struct mtd_info *mtd, loff_t ofs)
446 {
447 	struct nand_chip *chip = mtd_to_nand(mtd);
448 	int res, ret = 0;
449 
450 	if (!(chip->bbt_options & NAND_BBT_NO_OOB_BBM)) {
451 		struct erase_info einfo;
452 
453 		/* Attempt erase before marking OOB */
454 		memset(&einfo, 0, sizeof(einfo));
455 		einfo.mtd = mtd;
456 		einfo.addr = ofs;
457 		einfo.len = 1ULL << chip->phys_erase_shift;
458 		nand_erase_nand(mtd, &einfo, 0);
459 
460 		/* Write bad block marker to OOB */
461 		nand_get_device(mtd, FL_WRITING);
462 		ret = chip->block_markbad(mtd, ofs);
463 		nand_release_device(mtd);
464 	}
465 
466 	/* Mark block bad in BBT */
467 	if (chip->bbt) {
468 		res = nand_markbad_bbt(mtd, ofs);
469 		if (!ret)
470 			ret = res;
471 	}
472 
473 	if (!ret)
474 		mtd->ecc_stats.badblocks++;
475 
476 	return ret;
477 }
478 
479 /**
480  * nand_check_wp - [GENERIC] check if the chip is write protected
481  * @mtd: MTD device structure
482  *
483  * Check, if the device is write protected. The function expects, that the
484  * device is already selected.
485  */
486 static int nand_check_wp(struct mtd_info *mtd)
487 {
488 	struct nand_chip *chip = mtd_to_nand(mtd);
489 
490 	/* Broken xD cards report WP despite being writable */
491 	if (chip->options & NAND_BROKEN_XD)
492 		return 0;
493 
494 	/* Check the WP bit */
495 	chip->cmdfunc(mtd, NAND_CMD_STATUS, -1, -1);
496 	return (chip->read_byte(mtd) & NAND_STATUS_WP) ? 0 : 1;
497 }
498 
499 /**
500  * nand_block_isreserved - [GENERIC] Check if a block is marked reserved.
501  * @mtd: MTD device structure
502  * @ofs: offset from device start
503  *
504  * Check if the block is marked as reserved.
505  */
506 static int nand_block_isreserved(struct mtd_info *mtd, loff_t ofs)
507 {
508 	struct nand_chip *chip = mtd_to_nand(mtd);
509 
510 	if (!chip->bbt)
511 		return 0;
512 	/* Return info from the table */
513 	return nand_isreserved_bbt(mtd, ofs);
514 }
515 
516 /**
517  * nand_block_checkbad - [GENERIC] Check if a block is marked bad
518  * @mtd: MTD device structure
519  * @ofs: offset from device start
520  * @allowbbt: 1, if its allowed to access the bbt area
521  *
522  * Check, if the block is bad. Either by reading the bad block table or
523  * calling of the scan function.
524  */
525 static int nand_block_checkbad(struct mtd_info *mtd, loff_t ofs, int allowbbt)
526 {
527 	struct nand_chip *chip = mtd_to_nand(mtd);
528 
529 	if (!(chip->options & NAND_SKIP_BBTSCAN) &&
530 	    !(chip->options & NAND_BBT_SCANNED)) {
531 		chip->options |= NAND_BBT_SCANNED;
532 		chip->scan_bbt(mtd);
533 	}
534 
535 	if (!chip->bbt)
536 		return chip->block_bad(mtd, ofs);
537 
538 	/* Return info from the table */
539 	return nand_isbad_bbt(mtd, ofs, allowbbt);
540 }
541 
542 /**
543  * nand_wait_ready - [GENERIC] Wait for the ready pin after commands.
544  * @mtd: MTD device structure
545  *
546  * Wait for the ready pin after a command, and warn if a timeout occurs.
547  */
548 void nand_wait_ready(struct mtd_info *mtd)
549 {
550 	struct nand_chip *chip = mtd_to_nand(mtd);
551 	u32 timeo = (CONFIG_SYS_HZ * 400) / 1000;
552 	u32 time_start;
553 
554 	time_start = get_timer(0);
555 	/* Wait until command is processed or timeout occurs */
556 	while (get_timer(time_start) < timeo) {
557 		if (chip->dev_ready)
558 			if (chip->dev_ready(mtd))
559 				break;
560 	}
561 
562 	if (!chip->dev_ready(mtd))
563 		pr_warn("timeout while waiting for chip to become ready\n");
564 }
565 EXPORT_SYMBOL_GPL(nand_wait_ready);
566 
567 /**
568  * nand_wait_status_ready - [GENERIC] Wait for the ready status after commands.
569  * @mtd: MTD device structure
570  * @timeo: Timeout in ms
571  *
572  * Wait for status ready (i.e. command done) or timeout.
573  */
574 static void nand_wait_status_ready(struct mtd_info *mtd, unsigned long timeo)
575 {
576 	register struct nand_chip *chip = mtd_to_nand(mtd);
577 	u32 time_start;
578 
579 	timeo = (CONFIG_SYS_HZ * timeo) / 1000;
580 	time_start = get_timer(0);
581 	while (get_timer(time_start) < timeo) {
582 		if ((chip->read_byte(mtd) & NAND_STATUS_READY))
583 			break;
584 		WATCHDOG_RESET();
585 	}
586 };
587 
588 /**
589  * nand_command - [DEFAULT] Send command to NAND device
590  * @mtd: MTD device structure
591  * @command: the command to be sent
592  * @column: the column address for this command, -1 if none
593  * @page_addr: the page address for this command, -1 if none
594  *
595  * Send command to NAND device. This function is used for small page devices
596  * (512 Bytes per page).
597  */
598 static void nand_command(struct mtd_info *mtd, unsigned int command,
599 			 int column, int page_addr)
600 {
601 	register struct nand_chip *chip = mtd_to_nand(mtd);
602 	int ctrl = NAND_CTRL_CLE | NAND_CTRL_CHANGE;
603 
604 	/* Write out the command to the device */
605 	if (command == NAND_CMD_SEQIN) {
606 		int readcmd;
607 
608 		if (column >= mtd->writesize) {
609 			/* OOB area */
610 			column -= mtd->writesize;
611 			readcmd = NAND_CMD_READOOB;
612 		} else if (column < 256) {
613 			/* First 256 bytes --> READ0 */
614 			readcmd = NAND_CMD_READ0;
615 		} else {
616 			column -= 256;
617 			readcmd = NAND_CMD_READ1;
618 		}
619 		chip->cmd_ctrl(mtd, readcmd, ctrl);
620 		ctrl &= ~NAND_CTRL_CHANGE;
621 	}
622 	chip->cmd_ctrl(mtd, command, ctrl);
623 
624 	/* Address cycle, when necessary */
625 	ctrl = NAND_CTRL_ALE | NAND_CTRL_CHANGE;
626 	/* Serially input address */
627 	if (column != -1) {
628 		/* Adjust columns for 16 bit buswidth */
629 		if (chip->options & NAND_BUSWIDTH_16 &&
630 				!nand_opcode_8bits(command))
631 			column >>= 1;
632 		chip->cmd_ctrl(mtd, column, ctrl);
633 		ctrl &= ~NAND_CTRL_CHANGE;
634 	}
635 	if (page_addr != -1) {
636 		chip->cmd_ctrl(mtd, page_addr, ctrl);
637 		ctrl &= ~NAND_CTRL_CHANGE;
638 		chip->cmd_ctrl(mtd, page_addr >> 8, ctrl);
639 		if (chip->options & NAND_ROW_ADDR_3)
640 			chip->cmd_ctrl(mtd, page_addr >> 16, ctrl);
641 	}
642 	chip->cmd_ctrl(mtd, NAND_CMD_NONE, NAND_NCE | NAND_CTRL_CHANGE);
643 
644 	/*
645 	 * Program and erase have their own busy handlers status and sequential
646 	 * in needs no delay
647 	 */
648 	switch (command) {
649 
650 	case NAND_CMD_PAGEPROG:
651 	case NAND_CMD_ERASE1:
652 	case NAND_CMD_ERASE2:
653 	case NAND_CMD_SEQIN:
654 	case NAND_CMD_STATUS:
655 	case NAND_CMD_READID:
656 	case NAND_CMD_SET_FEATURES:
657 		return;
658 
659 	case NAND_CMD_RESET:
660 		if (chip->dev_ready)
661 			break;
662 		udelay(chip->chip_delay);
663 		chip->cmd_ctrl(mtd, NAND_CMD_STATUS,
664 			       NAND_CTRL_CLE | NAND_CTRL_CHANGE);
665 		chip->cmd_ctrl(mtd,
666 			       NAND_CMD_NONE, NAND_NCE | NAND_CTRL_CHANGE);
667 		/* EZ-NAND can take upto 250ms as per ONFi v4.0 */
668 		nand_wait_status_ready(mtd, 250);
669 		return;
670 
671 		/* This applies to read commands */
672 	default:
673 		/*
674 		 * If we don't have access to the busy pin, we apply the given
675 		 * command delay
676 		 */
677 		if (!chip->dev_ready) {
678 			udelay(chip->chip_delay);
679 			return;
680 		}
681 	}
682 	/*
683 	 * Apply this short delay always to ensure that we do wait tWB in
684 	 * any case on any machine.
685 	 */
686 	ndelay(100);
687 
688 	nand_wait_ready(mtd);
689 }
690 
691 /**
692  * nand_command_lp - [DEFAULT] Send command to NAND large page device
693  * @mtd: MTD device structure
694  * @command: the command to be sent
695  * @column: the column address for this command, -1 if none
696  * @page_addr: the page address for this command, -1 if none
697  *
698  * Send command to NAND device. This is the version for the new large page
699  * devices. We don't have the separate regions as we have in the small page
700  * devices. We must emulate NAND_CMD_READOOB to keep the code compatible.
701  */
702 static void nand_command_lp(struct mtd_info *mtd, unsigned int command,
703 			    int column, int page_addr)
704 {
705 	register struct nand_chip *chip = mtd_to_nand(mtd);
706 
707 	/* Emulate NAND_CMD_READOOB */
708 	if (command == NAND_CMD_READOOB) {
709 		column += mtd->writesize;
710 		command = NAND_CMD_READ0;
711 	}
712 
713 	/* Command latch cycle */
714 	chip->cmd_ctrl(mtd, command, NAND_NCE | NAND_CLE | NAND_CTRL_CHANGE);
715 
716 	if (column != -1 || page_addr != -1) {
717 		int ctrl = NAND_CTRL_CHANGE | NAND_NCE | NAND_ALE;
718 
719 		/* Serially input address */
720 		if (column != -1) {
721 			/* Adjust columns for 16 bit buswidth */
722 			if (chip->options & NAND_BUSWIDTH_16 &&
723 					!nand_opcode_8bits(command))
724 				column >>= 1;
725 			chip->cmd_ctrl(mtd, column, ctrl);
726 			ctrl &= ~NAND_CTRL_CHANGE;
727 			chip->cmd_ctrl(mtd, column >> 8, ctrl);
728 		}
729 		if (page_addr != -1) {
730 			chip->cmd_ctrl(mtd, page_addr, ctrl);
731 			chip->cmd_ctrl(mtd, page_addr >> 8,
732 				       NAND_NCE | NAND_ALE);
733 			if (chip->options & NAND_ROW_ADDR_3)
734 				chip->cmd_ctrl(mtd, page_addr >> 16,
735 					       NAND_NCE | NAND_ALE);
736 		}
737 	}
738 	chip->cmd_ctrl(mtd, NAND_CMD_NONE, NAND_NCE | NAND_CTRL_CHANGE);
739 
740 	/*
741 	 * Program and erase have their own busy handlers status, sequential
742 	 * in and status need no delay.
743 	 */
744 	switch (command) {
745 
746 	case NAND_CMD_CACHEDPROG:
747 	case NAND_CMD_PAGEPROG:
748 	case NAND_CMD_ERASE1:
749 	case NAND_CMD_ERASE2:
750 	case NAND_CMD_SEQIN:
751 	case NAND_CMD_RNDIN:
752 	case NAND_CMD_STATUS:
753 	case NAND_CMD_READID:
754 	case NAND_CMD_SET_FEATURES:
755 		return;
756 
757 	case NAND_CMD_RESET:
758 		if (chip->dev_ready)
759 			break;
760 		udelay(chip->chip_delay);
761 		chip->cmd_ctrl(mtd, NAND_CMD_STATUS,
762 			       NAND_NCE | NAND_CLE | NAND_CTRL_CHANGE);
763 		chip->cmd_ctrl(mtd, NAND_CMD_NONE,
764 			       NAND_NCE | NAND_CTRL_CHANGE);
765 		/* EZ-NAND can take upto 250ms as per ONFi v4.0 */
766 		nand_wait_status_ready(mtd, 250);
767 		return;
768 
769 	case NAND_CMD_RNDOUT:
770 		/* No ready / busy check necessary */
771 		chip->cmd_ctrl(mtd, NAND_CMD_RNDOUTSTART,
772 			       NAND_NCE | NAND_CLE | NAND_CTRL_CHANGE);
773 		chip->cmd_ctrl(mtd, NAND_CMD_NONE,
774 			       NAND_NCE | NAND_CTRL_CHANGE);
775 		return;
776 
777 	case NAND_CMD_READ0:
778 		chip->cmd_ctrl(mtd, NAND_CMD_READSTART,
779 			       NAND_NCE | NAND_CLE | NAND_CTRL_CHANGE);
780 		chip->cmd_ctrl(mtd, NAND_CMD_NONE,
781 			       NAND_NCE | NAND_CTRL_CHANGE);
782 
783 		/* This applies to read commands */
784 	default:
785 		/*
786 		 * If we don't have access to the busy pin, we apply the given
787 		 * command delay.
788 		 */
789 		if (!chip->dev_ready) {
790 			udelay(chip->chip_delay);
791 			return;
792 		}
793 	}
794 
795 	/*
796 	 * Apply this short delay always to ensure that we do wait tWB in
797 	 * any case on any machine.
798 	 */
799 	ndelay(100);
800 
801 	nand_wait_ready(mtd);
802 }
803 
804 /**
805  * panic_nand_get_device - [GENERIC] Get chip for selected access
806  * @chip: the nand chip descriptor
807  * @mtd: MTD device structure
808  * @new_state: the state which is requested
809  *
810  * Used when in panic, no locks are taken.
811  */
812 static void panic_nand_get_device(struct nand_chip *chip,
813 		      struct mtd_info *mtd, int new_state)
814 {
815 	/* Hardware controller shared among independent devices */
816 	chip->controller->active = chip;
817 	chip->state = new_state;
818 }
819 
820 /**
821  * nand_get_device - [GENERIC] Get chip for selected access
822  * @mtd: MTD device structure
823  * @new_state: the state which is requested
824  *
825  * Get the device and lock it for exclusive access
826  */
827 static int
828 nand_get_device(struct mtd_info *mtd, int new_state)
829 {
830 	struct nand_chip *chip = mtd_to_nand(mtd);
831 	chip->state = new_state;
832 	return 0;
833 }
834 
835 /**
836  * panic_nand_wait - [GENERIC] wait until the command is done
837  * @mtd: MTD device structure
838  * @chip: NAND chip structure
839  * @timeo: timeout
840  *
841  * Wait for command done. This is a helper function for nand_wait used when
842  * we are in interrupt context. May happen when in panic and trying to write
843  * an oops through mtdoops.
844  */
845 static void panic_nand_wait(struct mtd_info *mtd, struct nand_chip *chip,
846 			    unsigned long timeo)
847 {
848 	int i;
849 	for (i = 0; i < timeo; i++) {
850 		if (chip->dev_ready) {
851 			if (chip->dev_ready(mtd))
852 				break;
853 		} else {
854 			if (chip->read_byte(mtd) & NAND_STATUS_READY)
855 				break;
856 		}
857 		mdelay(1);
858 	}
859 }
860 
861 /**
862  * nand_wait - [DEFAULT] wait until the command is done
863  * @mtd: MTD device structure
864  * @chip: NAND chip structure
865  *
866  * Wait for command done. This applies to erase and program only.
867  */
868 static int nand_wait(struct mtd_info *mtd, struct nand_chip *chip)
869 {
870 	int status;
871 	unsigned long timeo = 400;
872 
873 	led_trigger_event(nand_led_trigger, LED_FULL);
874 
875 	/*
876 	 * Apply this short delay always to ensure that we do wait tWB in any
877 	 * case on any machine.
878 	 */
879 	ndelay(100);
880 
881 	chip->cmdfunc(mtd, NAND_CMD_STATUS, -1, -1);
882 
883  	u32 timer = (CONFIG_SYS_HZ * timeo) / 1000;
884  	u32 time_start;
885 
886  	time_start = get_timer(0);
887  	while (get_timer(time_start) < timer) {
888 		if (chip->dev_ready) {
889 			if (chip->dev_ready(mtd))
890 				break;
891 		} else {
892 			if (chip->read_byte(mtd) & NAND_STATUS_READY)
893 				break;
894 		}
895 	}
896 	led_trigger_event(nand_led_trigger, LED_OFF);
897 
898 	status = (int)chip->read_byte(mtd);
899 	/* This can happen if in case of timeout or buggy dev_ready */
900 	WARN_ON(!(status & NAND_STATUS_READY));
901 	return status;
902 }
903 
904 /**
905  * nand_reset_data_interface - Reset data interface and timings
906  * @chip: The NAND chip
907  * @chipnr: Internal die id
908  *
909  * Reset the Data interface and timings to ONFI mode 0.
910  *
911  * Returns 0 for success or negative error code otherwise.
912  */
913 static int nand_reset_data_interface(struct nand_chip *chip, int chipnr)
914 {
915 	struct mtd_info *mtd = nand_to_mtd(chip);
916 	const struct nand_data_interface *conf;
917 	int ret;
918 
919 	if (!chip->setup_data_interface)
920 		return 0;
921 
922 	/*
923 	 * The ONFI specification says:
924 	 * "
925 	 * To transition from NV-DDR or NV-DDR2 to the SDR data
926 	 * interface, the host shall use the Reset (FFh) command
927 	 * using SDR timing mode 0. A device in any timing mode is
928 	 * required to recognize Reset (FFh) command issued in SDR
929 	 * timing mode 0.
930 	 * "
931 	 *
932 	 * Configure the data interface in SDR mode and set the
933 	 * timings to timing mode 0.
934 	 */
935 
936 	conf = nand_get_default_data_interface();
937 	ret = chip->setup_data_interface(mtd, chipnr, conf);
938 	if (ret)
939 		pr_err("Failed to configure data interface to SDR timing mode 0\n");
940 
941 	return ret;
942 }
943 
944 /**
945  * nand_setup_data_interface - Setup the best data interface and timings
946  * @chip: The NAND chip
947  * @chipnr: Internal die id
948  *
949  * Find and configure the best data interface and NAND timings supported by
950  * the chip and the driver.
951  * First tries to retrieve supported timing modes from ONFI information,
952  * and if the NAND chip does not support ONFI, relies on the
953  * ->onfi_timing_mode_default specified in the nand_ids table.
954  *
955  * Returns 0 for success or negative error code otherwise.
956  */
957 static int nand_setup_data_interface(struct nand_chip *chip, int chipnr)
958 {
959 	struct mtd_info *mtd = nand_to_mtd(chip);
960 	int ret;
961 
962 	if (!chip->setup_data_interface || !chip->data_interface)
963 		return 0;
964 
965 	/*
966 	 * Ensure the timing mode has been changed on the chip side
967 	 * before changing timings on the controller side.
968 	 */
969 	if (chip->onfi_version) {
970 		u8 tmode_param[ONFI_SUBFEATURE_PARAM_LEN] = {
971 			chip->onfi_timing_mode_default,
972 		};
973 
974 		ret = chip->onfi_set_features(mtd, chip,
975 				ONFI_FEATURE_ADDR_TIMING_MODE,
976 				tmode_param);
977 		if (ret)
978 			goto err;
979 	}
980 
981 	ret = chip->setup_data_interface(mtd, chipnr, chip->data_interface);
982 err:
983 	return ret;
984 }
985 
986 /**
987  * nand_init_data_interface - find the best data interface and timings
988  * @chip: The NAND chip
989  *
990  * Find the best data interface and NAND timings supported by the chip
991  * and the driver.
992  * First tries to retrieve supported timing modes from ONFI information,
993  * and if the NAND chip does not support ONFI, relies on the
994  * ->onfi_timing_mode_default specified in the nand_ids table. After this
995  * function nand_chip->data_interface is initialized with the best timing mode
996  * available.
997  *
998  * Returns 0 for success or negative error code otherwise.
999  */
1000 static int nand_init_data_interface(struct nand_chip *chip)
1001 {
1002 	struct mtd_info *mtd = nand_to_mtd(chip);
1003 	int modes, mode, ret;
1004 
1005 	if (!chip->setup_data_interface)
1006 		return 0;
1007 
1008 	/*
1009 	 * First try to identify the best timings from ONFI parameters and
1010 	 * if the NAND does not support ONFI, fallback to the default ONFI
1011 	 * timing mode.
1012 	 */
1013 	modes = onfi_get_async_timing_mode(chip);
1014 	if (modes == ONFI_TIMING_MODE_UNKNOWN) {
1015 		if (!chip->onfi_timing_mode_default)
1016 			return 0;
1017 
1018 		modes = GENMASK(chip->onfi_timing_mode_default, 0);
1019 	}
1020 
1021 	chip->data_interface = kzalloc(sizeof(*chip->data_interface),
1022 				       GFP_KERNEL);
1023 	if (!chip->data_interface)
1024 		return -ENOMEM;
1025 
1026 	for (mode = fls(modes) - 1; mode >= 0; mode--) {
1027 		ret = onfi_init_data_interface(chip, chip->data_interface,
1028 					       NAND_SDR_IFACE, mode);
1029 		if (ret)
1030 			continue;
1031 
1032 		/* Pass -1 to only */
1033 		ret = chip->setup_data_interface(mtd,
1034 						 NAND_DATA_IFACE_CHECK_ONLY,
1035 						 chip->data_interface);
1036 		if (!ret) {
1037 			chip->onfi_timing_mode_default = mode;
1038 			break;
1039 		}
1040 	}
1041 
1042 	return 0;
1043 }
1044 
1045 static void __maybe_unused nand_release_data_interface(struct nand_chip *chip)
1046 {
1047 	kfree(chip->data_interface);
1048 }
1049 
1050 /**
1051  * nand_reset - Reset and initialize a NAND device
1052  * @chip: The NAND chip
1053  * @chipnr: Internal die id
1054  *
1055  * Returns 0 for success or negative error code otherwise
1056  */
1057 int nand_reset(struct nand_chip *chip, int chipnr)
1058 {
1059 	struct mtd_info *mtd = nand_to_mtd(chip);
1060 	int ret;
1061 
1062 	ret = nand_reset_data_interface(chip, chipnr);
1063 	if (ret)
1064 		return ret;
1065 
1066 	/*
1067 	 * The CS line has to be released before we can apply the new NAND
1068 	 * interface settings, hence this weird ->select_chip() dance.
1069 	 */
1070 	chip->select_chip(mtd, chipnr);
1071 	chip->cmdfunc(mtd, NAND_CMD_RESET, -1, -1);
1072 	chip->select_chip(mtd, -1);
1073 
1074 	chip->select_chip(mtd, chipnr);
1075 	ret = nand_setup_data_interface(chip, chipnr);
1076 	chip->select_chip(mtd, -1);
1077 	if (ret)
1078 		return ret;
1079 
1080 	return 0;
1081 }
1082 
1083 /**
1084  * nand_check_erased_buf - check if a buffer contains (almost) only 0xff data
1085  * @buf: buffer to test
1086  * @len: buffer length
1087  * @bitflips_threshold: maximum number of bitflips
1088  *
1089  * Check if a buffer contains only 0xff, which means the underlying region
1090  * has been erased and is ready to be programmed.
1091  * The bitflips_threshold specify the maximum number of bitflips before
1092  * considering the region is not erased.
1093  * Note: The logic of this function has been extracted from the memweight
1094  * implementation, except that nand_check_erased_buf function exit before
1095  * testing the whole buffer if the number of bitflips exceed the
1096  * bitflips_threshold value.
1097  *
1098  * Returns a positive number of bitflips less than or equal to
1099  * bitflips_threshold, or -ERROR_CODE for bitflips in excess of the
1100  * threshold.
1101  */
1102 static int nand_check_erased_buf(void *buf, int len, int bitflips_threshold)
1103 {
1104 	const unsigned char *bitmap = buf;
1105 	int bitflips = 0;
1106 	int weight;
1107 
1108 	for (; len && ((uintptr_t)bitmap) % sizeof(long);
1109 	     len--, bitmap++) {
1110 		weight = hweight8(*bitmap);
1111 		bitflips += BITS_PER_BYTE - weight;
1112 		if (unlikely(bitflips > bitflips_threshold))
1113 			return -EBADMSG;
1114 	}
1115 
1116 	for (; len >= 4; len -= 4, bitmap += 4) {
1117 		weight = hweight32(*((u32 *)bitmap));
1118 		bitflips += 32 - weight;
1119 		if (unlikely(bitflips > bitflips_threshold))
1120 			return -EBADMSG;
1121 	}
1122 
1123 	for (; len > 0; len--, bitmap++) {
1124 		weight = hweight8(*bitmap);
1125 		bitflips += BITS_PER_BYTE - weight;
1126 		if (unlikely(bitflips > bitflips_threshold))
1127 			return -EBADMSG;
1128 	}
1129 
1130 	return bitflips;
1131 }
1132 
1133 /**
1134  * nand_check_erased_ecc_chunk - check if an ECC chunk contains (almost) only
1135  *				 0xff data
1136  * @data: data buffer to test
1137  * @datalen: data length
1138  * @ecc: ECC buffer
1139  * @ecclen: ECC length
1140  * @extraoob: extra OOB buffer
1141  * @extraooblen: extra OOB length
1142  * @bitflips_threshold: maximum number of bitflips
1143  *
1144  * Check if a data buffer and its associated ECC and OOB data contains only
1145  * 0xff pattern, which means the underlying region has been erased and is
1146  * ready to be programmed.
1147  * The bitflips_threshold specify the maximum number of bitflips before
1148  * considering the region as not erased.
1149  *
1150  * Note:
1151  * 1/ ECC algorithms are working on pre-defined block sizes which are usually
1152  *    different from the NAND page size. When fixing bitflips, ECC engines will
1153  *    report the number of errors per chunk, and the NAND core infrastructure
1154  *    expect you to return the maximum number of bitflips for the whole page.
1155  *    This is why you should always use this function on a single chunk and
1156  *    not on the whole page. After checking each chunk you should update your
1157  *    max_bitflips value accordingly.
1158  * 2/ When checking for bitflips in erased pages you should not only check
1159  *    the payload data but also their associated ECC data, because a user might
1160  *    have programmed almost all bits to 1 but a few. In this case, we
1161  *    shouldn't consider the chunk as erased, and checking ECC bytes prevent
1162  *    this case.
1163  * 3/ The extraoob argument is optional, and should be used if some of your OOB
1164  *    data are protected by the ECC engine.
1165  *    It could also be used if you support subpages and want to attach some
1166  *    extra OOB data to an ECC chunk.
1167  *
1168  * Returns a positive number of bitflips less than or equal to
1169  * bitflips_threshold, or -ERROR_CODE for bitflips in excess of the
1170  * threshold. In case of success, the passed buffers are filled with 0xff.
1171  */
1172 int nand_check_erased_ecc_chunk(void *data, int datalen,
1173 				void *ecc, int ecclen,
1174 				void *extraoob, int extraooblen,
1175 				int bitflips_threshold)
1176 {
1177 	int data_bitflips = 0, ecc_bitflips = 0, extraoob_bitflips = 0;
1178 
1179 	data_bitflips = nand_check_erased_buf(data, datalen,
1180 					      bitflips_threshold);
1181 	if (data_bitflips < 0)
1182 		return data_bitflips;
1183 
1184 	bitflips_threshold -= data_bitflips;
1185 
1186 	ecc_bitflips = nand_check_erased_buf(ecc, ecclen, bitflips_threshold);
1187 	if (ecc_bitflips < 0)
1188 		return ecc_bitflips;
1189 
1190 	bitflips_threshold -= ecc_bitflips;
1191 
1192 	extraoob_bitflips = nand_check_erased_buf(extraoob, extraooblen,
1193 						  bitflips_threshold);
1194 	if (extraoob_bitflips < 0)
1195 		return extraoob_bitflips;
1196 
1197 	if (data_bitflips)
1198 		memset(data, 0xff, datalen);
1199 
1200 	if (ecc_bitflips)
1201 		memset(ecc, 0xff, ecclen);
1202 
1203 	if (extraoob_bitflips)
1204 		memset(extraoob, 0xff, extraooblen);
1205 
1206 	return data_bitflips + ecc_bitflips + extraoob_bitflips;
1207 }
1208 EXPORT_SYMBOL(nand_check_erased_ecc_chunk);
1209 
1210 /**
1211  * nand_read_page_raw - [INTERN] read raw page data without ecc
1212  * @mtd: mtd info structure
1213  * @chip: nand chip info structure
1214  * @buf: buffer to store read data
1215  * @oob_required: caller requires OOB data read to chip->oob_poi
1216  * @page: page number to read
1217  *
1218  * Not for syndrome calculating ECC controllers, which use a special oob layout.
1219  */
1220 static int nand_read_page_raw(struct mtd_info *mtd, struct nand_chip *chip,
1221 			      uint8_t *buf, int oob_required, int page)
1222 {
1223 	chip->read_buf(mtd, buf, mtd->writesize);
1224 	if (oob_required)
1225 		chip->read_buf(mtd, chip->oob_poi, mtd->oobsize);
1226 	return 0;
1227 }
1228 
1229 /**
1230  * nand_read_page_raw_syndrome - [INTERN] read raw page data without ecc
1231  * @mtd: mtd info structure
1232  * @chip: nand chip info structure
1233  * @buf: buffer to store read data
1234  * @oob_required: caller requires OOB data read to chip->oob_poi
1235  * @page: page number to read
1236  *
1237  * We need a special oob layout and handling even when OOB isn't used.
1238  */
1239 static int nand_read_page_raw_syndrome(struct mtd_info *mtd,
1240 				       struct nand_chip *chip, uint8_t *buf,
1241 				       int oob_required, int page)
1242 {
1243 	int eccsize = chip->ecc.size;
1244 	int eccbytes = chip->ecc.bytes;
1245 	uint8_t *oob = chip->oob_poi;
1246 	int steps, size;
1247 
1248 	for (steps = chip->ecc.steps; steps > 0; steps--) {
1249 		chip->read_buf(mtd, buf, eccsize);
1250 		buf += eccsize;
1251 
1252 		if (chip->ecc.prepad) {
1253 			chip->read_buf(mtd, oob, chip->ecc.prepad);
1254 			oob += chip->ecc.prepad;
1255 		}
1256 
1257 		chip->read_buf(mtd, oob, eccbytes);
1258 		oob += eccbytes;
1259 
1260 		if (chip->ecc.postpad) {
1261 			chip->read_buf(mtd, oob, chip->ecc.postpad);
1262 			oob += chip->ecc.postpad;
1263 		}
1264 	}
1265 
1266 	size = mtd->oobsize - (oob - chip->oob_poi);
1267 	if (size)
1268 		chip->read_buf(mtd, oob, size);
1269 
1270 	return 0;
1271 }
1272 
1273 /**
1274  * nand_read_page_swecc - [REPLACEABLE] software ECC based page read function
1275  * @mtd: mtd info structure
1276  * @chip: nand chip info structure
1277  * @buf: buffer to store read data
1278  * @oob_required: caller requires OOB data read to chip->oob_poi
1279  * @page: page number to read
1280  */
1281 static int nand_read_page_swecc(struct mtd_info *mtd, struct nand_chip *chip,
1282 				uint8_t *buf, int oob_required, int page)
1283 {
1284 	int i, eccsize = chip->ecc.size;
1285 	int eccbytes = chip->ecc.bytes;
1286 	int eccsteps = chip->ecc.steps;
1287 	uint8_t *p = buf;
1288 	uint8_t *ecc_calc = chip->buffers->ecccalc;
1289 	uint8_t *ecc_code = chip->buffers->ecccode;
1290 	uint32_t *eccpos = chip->ecc.layout->eccpos;
1291 	unsigned int max_bitflips = 0;
1292 
1293 	chip->ecc.read_page_raw(mtd, chip, buf, 1, page);
1294 
1295 	for (i = 0; eccsteps; eccsteps--, i += eccbytes, p += eccsize)
1296 		chip->ecc.calculate(mtd, p, &ecc_calc[i]);
1297 
1298 	for (i = 0; i < chip->ecc.total; i++)
1299 		ecc_code[i] = chip->oob_poi[eccpos[i]];
1300 
1301 	eccsteps = chip->ecc.steps;
1302 	p = buf;
1303 
1304 	for (i = 0 ; eccsteps; eccsteps--, i += eccbytes, p += eccsize) {
1305 		int stat;
1306 
1307 		stat = chip->ecc.correct(mtd, p, &ecc_code[i], &ecc_calc[i]);
1308 		if (stat < 0) {
1309 			mtd->ecc_stats.failed++;
1310 		} else {
1311 			mtd->ecc_stats.corrected += stat;
1312 			max_bitflips = max_t(unsigned int, max_bitflips, stat);
1313 		}
1314 	}
1315 	return max_bitflips;
1316 }
1317 
1318 /**
1319  * nand_read_subpage - [REPLACEABLE] ECC based sub-page read function
1320  * @mtd: mtd info structure
1321  * @chip: nand chip info structure
1322  * @data_offs: offset of requested data within the page
1323  * @readlen: data length
1324  * @bufpoi: buffer to store read data
1325  * @page: page number to read
1326  */
1327 static int nand_read_subpage(struct mtd_info *mtd, struct nand_chip *chip,
1328 			uint32_t data_offs, uint32_t readlen, uint8_t *bufpoi,
1329 			int page)
1330 {
1331 	int start_step, end_step, num_steps;
1332 	uint32_t *eccpos = chip->ecc.layout->eccpos;
1333 	uint8_t *p;
1334 	int data_col_addr, i, gaps = 0;
1335 	int datafrag_len, eccfrag_len, aligned_len, aligned_pos;
1336 	int busw = (chip->options & NAND_BUSWIDTH_16) ? 2 : 1;
1337 	int index;
1338 	unsigned int max_bitflips = 0;
1339 
1340 	/* Column address within the page aligned to ECC size (256bytes) */
1341 	start_step = data_offs / chip->ecc.size;
1342 	end_step = (data_offs + readlen - 1) / chip->ecc.size;
1343 	num_steps = end_step - start_step + 1;
1344 	index = start_step * chip->ecc.bytes;
1345 
1346 	/* Data size aligned to ECC ecc.size */
1347 	datafrag_len = num_steps * chip->ecc.size;
1348 	eccfrag_len = num_steps * chip->ecc.bytes;
1349 
1350 	data_col_addr = start_step * chip->ecc.size;
1351 	/* If we read not a page aligned data */
1352 	if (data_col_addr != 0)
1353 		chip->cmdfunc(mtd, NAND_CMD_RNDOUT, data_col_addr, -1);
1354 
1355 	p = bufpoi + data_col_addr;
1356 	chip->read_buf(mtd, p, datafrag_len);
1357 
1358 	/* Calculate ECC */
1359 	for (i = 0; i < eccfrag_len ; i += chip->ecc.bytes, p += chip->ecc.size)
1360 		chip->ecc.calculate(mtd, p, &chip->buffers->ecccalc[i]);
1361 
1362 	/*
1363 	 * The performance is faster if we position offsets according to
1364 	 * ecc.pos. Let's make sure that there are no gaps in ECC positions.
1365 	 */
1366 	for (i = 0; i < eccfrag_len - 1; i++) {
1367 		if (eccpos[i + index] + 1 != eccpos[i + index + 1]) {
1368 			gaps = 1;
1369 			break;
1370 		}
1371 	}
1372 	if (gaps) {
1373 		chip->cmdfunc(mtd, NAND_CMD_RNDOUT, mtd->writesize, -1);
1374 		chip->read_buf(mtd, chip->oob_poi, mtd->oobsize);
1375 	} else {
1376 		/*
1377 		 * Send the command to read the particular ECC bytes take care
1378 		 * about buswidth alignment in read_buf.
1379 		 */
1380 		aligned_pos = eccpos[index] & ~(busw - 1);
1381 		aligned_len = eccfrag_len;
1382 		if (eccpos[index] & (busw - 1))
1383 			aligned_len++;
1384 		if (eccpos[index + (num_steps * chip->ecc.bytes)] & (busw - 1))
1385 			aligned_len++;
1386 
1387 		chip->cmdfunc(mtd, NAND_CMD_RNDOUT,
1388 					mtd->writesize + aligned_pos, -1);
1389 		chip->read_buf(mtd, &chip->oob_poi[aligned_pos], aligned_len);
1390 	}
1391 
1392 	for (i = 0; i < eccfrag_len; i++)
1393 		chip->buffers->ecccode[i] = chip->oob_poi[eccpos[i + index]];
1394 
1395 	p = bufpoi + data_col_addr;
1396 	for (i = 0; i < eccfrag_len ; i += chip->ecc.bytes, p += chip->ecc.size) {
1397 		int stat;
1398 
1399 		stat = chip->ecc.correct(mtd, p,
1400 			&chip->buffers->ecccode[i], &chip->buffers->ecccalc[i]);
1401 		if (stat == -EBADMSG &&
1402 		    (chip->ecc.options & NAND_ECC_GENERIC_ERASED_CHECK)) {
1403 			/* check for empty pages with bitflips */
1404 			stat = nand_check_erased_ecc_chunk(p, chip->ecc.size,
1405 						&chip->buffers->ecccode[i],
1406 						chip->ecc.bytes,
1407 						NULL, 0,
1408 						chip->ecc.strength);
1409 		}
1410 
1411 		if (stat < 0) {
1412 			mtd->ecc_stats.failed++;
1413 		} else {
1414 			mtd->ecc_stats.corrected += stat;
1415 			max_bitflips = max_t(unsigned int, max_bitflips, stat);
1416 		}
1417 	}
1418 	return max_bitflips;
1419 }
1420 
1421 /**
1422  * nand_read_page_hwecc - [REPLACEABLE] hardware ECC based page read function
1423  * @mtd: mtd info structure
1424  * @chip: nand chip info structure
1425  * @buf: buffer to store read data
1426  * @oob_required: caller requires OOB data read to chip->oob_poi
1427  * @page: page number to read
1428  *
1429  * Not for syndrome calculating ECC controllers which need a special oob layout.
1430  */
1431 static int nand_read_page_hwecc(struct mtd_info *mtd, struct nand_chip *chip,
1432 				uint8_t *buf, int oob_required, int page)
1433 {
1434 	int i, eccsize = chip->ecc.size;
1435 	int eccbytes = chip->ecc.bytes;
1436 	int eccsteps = chip->ecc.steps;
1437 	uint8_t *p = buf;
1438 	uint8_t *ecc_calc = chip->buffers->ecccalc;
1439 	uint8_t *ecc_code = chip->buffers->ecccode;
1440 	uint32_t *eccpos = chip->ecc.layout->eccpos;
1441 	unsigned int max_bitflips = 0;
1442 
1443 	for (i = 0; eccsteps; eccsteps--, i += eccbytes, p += eccsize) {
1444 		chip->ecc.hwctl(mtd, NAND_ECC_READ);
1445 		chip->read_buf(mtd, p, eccsize);
1446 		chip->ecc.calculate(mtd, p, &ecc_calc[i]);
1447 	}
1448 	chip->read_buf(mtd, chip->oob_poi, mtd->oobsize);
1449 
1450 	for (i = 0; i < chip->ecc.total; i++)
1451 		ecc_code[i] = chip->oob_poi[eccpos[i]];
1452 
1453 	eccsteps = chip->ecc.steps;
1454 	p = buf;
1455 
1456 	for (i = 0 ; eccsteps; eccsteps--, i += eccbytes, p += eccsize) {
1457 		int stat;
1458 
1459 		stat = chip->ecc.correct(mtd, p, &ecc_code[i], &ecc_calc[i]);
1460 		if (stat == -EBADMSG &&
1461 		    (chip->ecc.options & NAND_ECC_GENERIC_ERASED_CHECK)) {
1462 			/* check for empty pages with bitflips */
1463 			stat = nand_check_erased_ecc_chunk(p, eccsize,
1464 						&ecc_code[i], eccbytes,
1465 						NULL, 0,
1466 						chip->ecc.strength);
1467 		}
1468 
1469 		if (stat < 0) {
1470 			mtd->ecc_stats.failed++;
1471 		} else {
1472 			mtd->ecc_stats.corrected += stat;
1473 			max_bitflips = max_t(unsigned int, max_bitflips, stat);
1474 		}
1475 	}
1476 	return max_bitflips;
1477 }
1478 
1479 /**
1480  * nand_read_page_hwecc_oob_first - [REPLACEABLE] hw ecc, read oob first
1481  * @mtd: mtd info structure
1482  * @chip: nand chip info structure
1483  * @buf: buffer to store read data
1484  * @oob_required: caller requires OOB data read to chip->oob_poi
1485  * @page: page number to read
1486  *
1487  * Hardware ECC for large page chips, require OOB to be read first. For this
1488  * ECC mode, the write_page method is re-used from ECC_HW. These methods
1489  * read/write ECC from the OOB area, unlike the ECC_HW_SYNDROME support with
1490  * multiple ECC steps, follows the "infix ECC" scheme and reads/writes ECC from
1491  * the data area, by overwriting the NAND manufacturer bad block markings.
1492  */
1493 static int nand_read_page_hwecc_oob_first(struct mtd_info *mtd,
1494 	struct nand_chip *chip, uint8_t *buf, int oob_required, int page)
1495 {
1496 	int i, eccsize = chip->ecc.size;
1497 	int eccbytes = chip->ecc.bytes;
1498 	int eccsteps = chip->ecc.steps;
1499 	uint8_t *p = buf;
1500 	uint8_t *ecc_code = chip->buffers->ecccode;
1501 	uint32_t *eccpos = chip->ecc.layout->eccpos;
1502 	uint8_t *ecc_calc = chip->buffers->ecccalc;
1503 	unsigned int max_bitflips = 0;
1504 
1505 	/* Read the OOB area first */
1506 	chip->cmdfunc(mtd, NAND_CMD_READOOB, 0, page);
1507 	chip->read_buf(mtd, chip->oob_poi, mtd->oobsize);
1508 	chip->cmdfunc(mtd, NAND_CMD_READ0, 0, page);
1509 
1510 	for (i = 0; i < chip->ecc.total; i++)
1511 		ecc_code[i] = chip->oob_poi[eccpos[i]];
1512 
1513 	for (i = 0; eccsteps; eccsteps--, i += eccbytes, p += eccsize) {
1514 		int stat;
1515 
1516 		chip->ecc.hwctl(mtd, NAND_ECC_READ);
1517 		chip->read_buf(mtd, p, eccsize);
1518 		chip->ecc.calculate(mtd, p, &ecc_calc[i]);
1519 
1520 		stat = chip->ecc.correct(mtd, p, &ecc_code[i], NULL);
1521 		if (stat == -EBADMSG &&
1522 		    (chip->ecc.options & NAND_ECC_GENERIC_ERASED_CHECK)) {
1523 			/* check for empty pages with bitflips */
1524 			stat = nand_check_erased_ecc_chunk(p, eccsize,
1525 						&ecc_code[i], eccbytes,
1526 						NULL, 0,
1527 						chip->ecc.strength);
1528 		}
1529 
1530 		if (stat < 0) {
1531 			mtd->ecc_stats.failed++;
1532 		} else {
1533 			mtd->ecc_stats.corrected += stat;
1534 			max_bitflips = max_t(unsigned int, max_bitflips, stat);
1535 		}
1536 	}
1537 	return max_bitflips;
1538 }
1539 
1540 /**
1541  * nand_read_page_syndrome - [REPLACEABLE] hardware ECC syndrome based page read
1542  * @mtd: mtd info structure
1543  * @chip: nand chip info structure
1544  * @buf: buffer to store read data
1545  * @oob_required: caller requires OOB data read to chip->oob_poi
1546  * @page: page number to read
1547  *
1548  * The hw generator calculates the error syndrome automatically. Therefore we
1549  * need a special oob layout and handling.
1550  */
1551 static int nand_read_page_syndrome(struct mtd_info *mtd, struct nand_chip *chip,
1552 				   uint8_t *buf, int oob_required, int page)
1553 {
1554 	int i, eccsize = chip->ecc.size;
1555 	int eccbytes = chip->ecc.bytes;
1556 	int eccsteps = chip->ecc.steps;
1557 	int eccpadbytes = eccbytes + chip->ecc.prepad + chip->ecc.postpad;
1558 	uint8_t *p = buf;
1559 	uint8_t *oob = chip->oob_poi;
1560 	unsigned int max_bitflips = 0;
1561 
1562 	for (i = 0; eccsteps; eccsteps--, i += eccbytes, p += eccsize) {
1563 		int stat;
1564 
1565 		chip->ecc.hwctl(mtd, NAND_ECC_READ);
1566 		chip->read_buf(mtd, p, eccsize);
1567 
1568 		if (chip->ecc.prepad) {
1569 			chip->read_buf(mtd, oob, chip->ecc.prepad);
1570 			oob += chip->ecc.prepad;
1571 		}
1572 
1573 		chip->ecc.hwctl(mtd, NAND_ECC_READSYN);
1574 		chip->read_buf(mtd, oob, eccbytes);
1575 		stat = chip->ecc.correct(mtd, p, oob, NULL);
1576 
1577 		oob += eccbytes;
1578 
1579 		if (chip->ecc.postpad) {
1580 			chip->read_buf(mtd, oob, chip->ecc.postpad);
1581 			oob += chip->ecc.postpad;
1582 		}
1583 
1584 		if (stat == -EBADMSG &&
1585 		    (chip->ecc.options & NAND_ECC_GENERIC_ERASED_CHECK)) {
1586 			/* check for empty pages with bitflips */
1587 			stat = nand_check_erased_ecc_chunk(p, chip->ecc.size,
1588 							   oob - eccpadbytes,
1589 							   eccpadbytes,
1590 							   NULL, 0,
1591 							   chip->ecc.strength);
1592 		}
1593 
1594 		if (stat < 0) {
1595 			mtd->ecc_stats.failed++;
1596 		} else {
1597 			mtd->ecc_stats.corrected += stat;
1598 			max_bitflips = max_t(unsigned int, max_bitflips, stat);
1599 		}
1600 	}
1601 
1602 	/* Calculate remaining oob bytes */
1603 	i = mtd->oobsize - (oob - chip->oob_poi);
1604 	if (i)
1605 		chip->read_buf(mtd, oob, i);
1606 
1607 	return max_bitflips;
1608 }
1609 
1610 /**
1611  * nand_transfer_oob - [INTERN] Transfer oob to client buffer
1612  * @chip: nand chip structure
1613  * @oob: oob destination address
1614  * @ops: oob ops structure
1615  * @len: size of oob to transfer
1616  */
1617 static uint8_t *nand_transfer_oob(struct nand_chip *chip, uint8_t *oob,
1618 				  struct mtd_oob_ops *ops, size_t len)
1619 {
1620 	switch (ops->mode) {
1621 
1622 	case MTD_OPS_PLACE_OOB:
1623 	case MTD_OPS_RAW:
1624 		memcpy(oob, chip->oob_poi + ops->ooboffs, len);
1625 		return oob + len;
1626 
1627 	case MTD_OPS_AUTO_OOB: {
1628 		struct nand_oobfree *free = chip->ecc.layout->oobfree;
1629 		uint32_t boffs = 0, roffs = ops->ooboffs;
1630 		size_t bytes = 0;
1631 
1632 		for (; free->length && len; free++, len -= bytes) {
1633 			/* Read request not from offset 0? */
1634 			if (unlikely(roffs)) {
1635 				if (roffs >= free->length) {
1636 					roffs -= free->length;
1637 					continue;
1638 				}
1639 				boffs = free->offset + roffs;
1640 				bytes = min_t(size_t, len,
1641 					      (free->length - roffs));
1642 				roffs = 0;
1643 			} else {
1644 				bytes = min_t(size_t, len, free->length);
1645 				boffs = free->offset;
1646 			}
1647 			memcpy(oob, chip->oob_poi + boffs, bytes);
1648 			oob += bytes;
1649 		}
1650 		return oob;
1651 	}
1652 	default:
1653 		BUG();
1654 	}
1655 	return NULL;
1656 }
1657 
1658 /**
1659  * nand_setup_read_retry - [INTERN] Set the READ RETRY mode
1660  * @mtd: MTD device structure
1661  * @retry_mode: the retry mode to use
1662  *
1663  * Some vendors supply a special command to shift the Vt threshold, to be used
1664  * when there are too many bitflips in a page (i.e., ECC error). After setting
1665  * a new threshold, the host should retry reading the page.
1666  */
1667 static int nand_setup_read_retry(struct mtd_info *mtd, int retry_mode)
1668 {
1669 	struct nand_chip *chip = mtd_to_nand(mtd);
1670 
1671 	pr_debug("setting READ RETRY mode %d\n", retry_mode);
1672 
1673 	if (retry_mode >= chip->read_retries)
1674 		return -EINVAL;
1675 
1676 	if (!chip->setup_read_retry)
1677 		return -EOPNOTSUPP;
1678 
1679 	return chip->setup_read_retry(mtd, retry_mode);
1680 }
1681 
1682 /**
1683  * nand_do_read_ops - [INTERN] Read data with ECC
1684  * @mtd: MTD device structure
1685  * @from: offset to read from
1686  * @ops: oob ops structure
1687  *
1688  * Internal function. Called with chip held.
1689  */
1690 static int nand_do_read_ops(struct mtd_info *mtd, loff_t from,
1691 			    struct mtd_oob_ops *ops)
1692 {
1693 	int chipnr, page, realpage, col, bytes, aligned, oob_required;
1694 	struct nand_chip *chip = mtd_to_nand(mtd);
1695 	int ret = 0;
1696 	uint32_t readlen = ops->len;
1697 	uint32_t oobreadlen = ops->ooblen;
1698 	uint32_t max_oobsize = mtd_oobavail(mtd, ops);
1699 
1700 	uint8_t *bufpoi, *oob, *buf;
1701 	int use_bufpoi;
1702 	unsigned int max_bitflips = 0;
1703 	int retry_mode = 0;
1704 	bool ecc_fail = false;
1705 
1706 	chipnr = (int)(from >> chip->chip_shift);
1707 	chip->select_chip(mtd, chipnr);
1708 
1709 	realpage = (int)(from >> chip->page_shift);
1710 	page = realpage & chip->pagemask;
1711 
1712 	col = (int)(from & (mtd->writesize - 1));
1713 
1714 	buf = ops->datbuf;
1715 	oob = ops->oobbuf;
1716 	oob_required = oob ? 1 : 0;
1717 
1718 	while (1) {
1719 		unsigned int ecc_failures = mtd->ecc_stats.failed;
1720 
1721 		WATCHDOG_RESET();
1722 		bytes = min(mtd->writesize - col, readlen);
1723 		aligned = (bytes == mtd->writesize);
1724 
1725 		if (!aligned)
1726 			use_bufpoi = 1;
1727 		else if (chip->options & NAND_USE_BOUNCE_BUFFER)
1728 			use_bufpoi = !IS_ALIGNED((unsigned long)buf,
1729 						 chip->buf_align);
1730 		else
1731 			use_bufpoi = 0;
1732 
1733 		/* Is the current page in the buffer? */
1734 		if (realpage != chip->pagebuf || oob) {
1735 			bufpoi = use_bufpoi ? chip->buffers->databuf : buf;
1736 
1737 			if (use_bufpoi && aligned)
1738 				pr_debug("%s: using read bounce buffer for buf@%p\n",
1739 						 __func__, buf);
1740 
1741 read_retry:
1742 			if (nand_standard_page_accessors(&chip->ecc))
1743 				chip->cmdfunc(mtd, NAND_CMD_READ0, 0x00, page);
1744 
1745 			/*
1746 			 * Now read the page into the buffer.  Absent an error,
1747 			 * the read methods return max bitflips per ecc step.
1748 			 */
1749 			if (unlikely(ops->mode == MTD_OPS_RAW))
1750 				ret = chip->ecc.read_page_raw(mtd, chip, bufpoi,
1751 							      oob_required,
1752 							      page);
1753 			else if (!aligned && NAND_HAS_SUBPAGE_READ(chip) &&
1754 				 !oob)
1755 				ret = chip->ecc.read_subpage(mtd, chip,
1756 							col, bytes, bufpoi,
1757 							page);
1758 			else
1759 				ret = chip->ecc.read_page(mtd, chip, bufpoi,
1760 							  oob_required, page);
1761 			if (ret < 0) {
1762 				if (use_bufpoi)
1763 					/* Invalidate page cache */
1764 					chip->pagebuf = -1;
1765 				break;
1766 			}
1767 
1768 			max_bitflips = max_t(unsigned int, max_bitflips, ret);
1769 
1770 			/* Transfer not aligned data */
1771 			if (use_bufpoi) {
1772 				if (!NAND_HAS_SUBPAGE_READ(chip) && !oob &&
1773 				    !(mtd->ecc_stats.failed - ecc_failures) &&
1774 				    (ops->mode != MTD_OPS_RAW)) {
1775 					chip->pagebuf = realpage;
1776 					chip->pagebuf_bitflips = ret;
1777 				} else {
1778 					/* Invalidate page cache */
1779 					chip->pagebuf = -1;
1780 				}
1781 				memcpy(buf, chip->buffers->databuf + col, bytes);
1782 			}
1783 
1784 			if (unlikely(oob)) {
1785 				int toread = min(oobreadlen, max_oobsize);
1786 
1787 				if (toread) {
1788 					oob = nand_transfer_oob(chip,
1789 						oob, ops, toread);
1790 					oobreadlen -= toread;
1791 				}
1792 			}
1793 
1794 			if (chip->options & NAND_NEED_READRDY) {
1795 				/* Apply delay or wait for ready/busy pin */
1796 				if (!chip->dev_ready)
1797 					udelay(chip->chip_delay);
1798 				else
1799 					nand_wait_ready(mtd);
1800 			}
1801 
1802 			if (mtd->ecc_stats.failed - ecc_failures) {
1803 				if (retry_mode + 1 < chip->read_retries) {
1804 					retry_mode++;
1805 					ret = nand_setup_read_retry(mtd,
1806 							retry_mode);
1807 					if (ret < 0)
1808 						break;
1809 
1810 					/* Reset failures; retry */
1811 					mtd->ecc_stats.failed = ecc_failures;
1812 					goto read_retry;
1813 				} else {
1814 					/* No more retry modes; real failure */
1815 					ecc_fail = true;
1816 				}
1817 			}
1818 
1819 			buf += bytes;
1820 		} else {
1821 			memcpy(buf, chip->buffers->databuf + col, bytes);
1822 			buf += bytes;
1823 			max_bitflips = max_t(unsigned int, max_bitflips,
1824 					     chip->pagebuf_bitflips);
1825 		}
1826 
1827 		readlen -= bytes;
1828 
1829 		/* Reset to retry mode 0 */
1830 		if (retry_mode) {
1831 			ret = nand_setup_read_retry(mtd, 0);
1832 			if (ret < 0)
1833 				break;
1834 			retry_mode = 0;
1835 		}
1836 
1837 		if (!readlen)
1838 			break;
1839 
1840 		/* For subsequent reads align to page boundary */
1841 		col = 0;
1842 		/* Increment page address */
1843 		realpage++;
1844 
1845 		page = realpage & chip->pagemask;
1846 		/* Check, if we cross a chip boundary */
1847 		if (!page) {
1848 			chipnr++;
1849 			chip->select_chip(mtd, -1);
1850 			chip->select_chip(mtd, chipnr);
1851 		}
1852 	}
1853 	chip->select_chip(mtd, -1);
1854 
1855 	ops->retlen = ops->len - (size_t) readlen;
1856 	if (oob)
1857 		ops->oobretlen = ops->ooblen - oobreadlen;
1858 
1859 	if (ret < 0)
1860 		return ret;
1861 
1862 	if (ecc_fail)
1863 		return -EBADMSG;
1864 
1865 	return max_bitflips;
1866 }
1867 
1868 /**
1869  * nand_read_oob_std - [REPLACEABLE] the most common OOB data read function
1870  * @mtd: mtd info structure
1871  * @chip: nand chip info structure
1872  * @page: page number to read
1873  */
1874 static int nand_read_oob_std(struct mtd_info *mtd, struct nand_chip *chip,
1875 			     int page)
1876 {
1877 	chip->cmdfunc(mtd, NAND_CMD_READOOB, 0, page);
1878 	chip->read_buf(mtd, chip->oob_poi, mtd->oobsize);
1879 	return 0;
1880 }
1881 
1882 /**
1883  * nand_read_oob_syndrome - [REPLACEABLE] OOB data read function for HW ECC
1884  *			    with syndromes
1885  * @mtd: mtd info structure
1886  * @chip: nand chip info structure
1887  * @page: page number to read
1888  */
1889 static int nand_read_oob_syndrome(struct mtd_info *mtd, struct nand_chip *chip,
1890 				  int page)
1891 {
1892 	int length = mtd->oobsize;
1893 	int chunk = chip->ecc.bytes + chip->ecc.prepad + chip->ecc.postpad;
1894 	int eccsize = chip->ecc.size;
1895 	uint8_t *bufpoi = chip->oob_poi;
1896 	int i, toread, sndrnd = 0, pos;
1897 
1898 	chip->cmdfunc(mtd, NAND_CMD_READ0, chip->ecc.size, page);
1899 	for (i = 0; i < chip->ecc.steps; i++) {
1900 		if (sndrnd) {
1901 			pos = eccsize + i * (eccsize + chunk);
1902 			if (mtd->writesize > 512)
1903 				chip->cmdfunc(mtd, NAND_CMD_RNDOUT, pos, -1);
1904 			else
1905 				chip->cmdfunc(mtd, NAND_CMD_READ0, pos, page);
1906 		} else
1907 			sndrnd = 1;
1908 		toread = min_t(int, length, chunk);
1909 		chip->read_buf(mtd, bufpoi, toread);
1910 		bufpoi += toread;
1911 		length -= toread;
1912 	}
1913 	if (length > 0)
1914 		chip->read_buf(mtd, bufpoi, length);
1915 
1916 	return 0;
1917 }
1918 
1919 /**
1920  * nand_write_oob_std - [REPLACEABLE] the most common OOB data write function
1921  * @mtd: mtd info structure
1922  * @chip: nand chip info structure
1923  * @page: page number to write
1924  */
1925 static int nand_write_oob_std(struct mtd_info *mtd, struct nand_chip *chip,
1926 			      int page)
1927 {
1928 	int status = 0;
1929 	const uint8_t *buf = chip->oob_poi;
1930 	int length = mtd->oobsize;
1931 
1932 	chip->cmdfunc(mtd, NAND_CMD_SEQIN, mtd->writesize, page);
1933 	chip->write_buf(mtd, buf, length);
1934 	/* Send command to program the OOB data */
1935 	chip->cmdfunc(mtd, NAND_CMD_PAGEPROG, -1, -1);
1936 
1937 	status = chip->waitfunc(mtd, chip);
1938 
1939 	return status & NAND_STATUS_FAIL ? -EIO : 0;
1940 }
1941 
1942 /**
1943  * nand_write_oob_syndrome - [REPLACEABLE] OOB data write function for HW ECC
1944  *			     with syndrome - only for large page flash
1945  * @mtd: mtd info structure
1946  * @chip: nand chip info structure
1947  * @page: page number to write
1948  */
1949 static int nand_write_oob_syndrome(struct mtd_info *mtd,
1950 				   struct nand_chip *chip, int page)
1951 {
1952 	int chunk = chip->ecc.bytes + chip->ecc.prepad + chip->ecc.postpad;
1953 	int eccsize = chip->ecc.size, length = mtd->oobsize;
1954 	int i, len, pos, status = 0, sndcmd = 0, steps = chip->ecc.steps;
1955 	const uint8_t *bufpoi = chip->oob_poi;
1956 
1957 	/*
1958 	 * data-ecc-data-ecc ... ecc-oob
1959 	 * or
1960 	 * data-pad-ecc-pad-data-pad .... ecc-pad-oob
1961 	 */
1962 	if (!chip->ecc.prepad && !chip->ecc.postpad) {
1963 		pos = steps * (eccsize + chunk);
1964 		steps = 0;
1965 	} else
1966 		pos = eccsize;
1967 
1968 	chip->cmdfunc(mtd, NAND_CMD_SEQIN, pos, page);
1969 	for (i = 0; i < steps; i++) {
1970 		if (sndcmd) {
1971 			if (mtd->writesize <= 512) {
1972 				uint32_t fill = 0xFFFFFFFF;
1973 
1974 				len = eccsize;
1975 				while (len > 0) {
1976 					int num = min_t(int, len, 4);
1977 					chip->write_buf(mtd, (uint8_t *)&fill,
1978 							num);
1979 					len -= num;
1980 				}
1981 			} else {
1982 				pos = eccsize + i * (eccsize + chunk);
1983 				chip->cmdfunc(mtd, NAND_CMD_RNDIN, pos, -1);
1984 			}
1985 		} else
1986 			sndcmd = 1;
1987 		len = min_t(int, length, chunk);
1988 		chip->write_buf(mtd, bufpoi, len);
1989 		bufpoi += len;
1990 		length -= len;
1991 	}
1992 	if (length > 0)
1993 		chip->write_buf(mtd, bufpoi, length);
1994 
1995 	chip->cmdfunc(mtd, NAND_CMD_PAGEPROG, -1, -1);
1996 	status = chip->waitfunc(mtd, chip);
1997 
1998 	return status & NAND_STATUS_FAIL ? -EIO : 0;
1999 }
2000 
2001 /**
2002  * nand_do_read_oob - [INTERN] NAND read out-of-band
2003  * @mtd: MTD device structure
2004  * @from: offset to read from
2005  * @ops: oob operations description structure
2006  *
2007  * NAND read out-of-band data from the spare area.
2008  */
2009 static int nand_do_read_oob(struct mtd_info *mtd, loff_t from,
2010 			    struct mtd_oob_ops *ops)
2011 {
2012 	int page, realpage, chipnr;
2013 	struct nand_chip *chip = mtd_to_nand(mtd);
2014 	struct mtd_ecc_stats stats;
2015 	int readlen = ops->ooblen;
2016 	int len;
2017 	uint8_t *buf = ops->oobbuf;
2018 	int ret = 0;
2019 
2020 	pr_debug("%s: from = 0x%08Lx, len = %i\n",
2021 			__func__, (unsigned long long)from, readlen);
2022 
2023 	stats = mtd->ecc_stats;
2024 
2025 	len = mtd_oobavail(mtd, ops);
2026 
2027 	if (unlikely(ops->ooboffs >= len)) {
2028 		pr_debug("%s: attempt to start read outside oob\n",
2029 				__func__);
2030 		return -EINVAL;
2031 	}
2032 
2033 	/* Do not allow reads past end of device */
2034 	if (unlikely(from >= mtd->size ||
2035 		     ops->ooboffs + readlen > ((mtd->size >> chip->page_shift) -
2036 					(from >> chip->page_shift)) * len)) {
2037 		pr_debug("%s: attempt to read beyond end of device\n",
2038 				__func__);
2039 		return -EINVAL;
2040 	}
2041 
2042 	chipnr = (int)(from >> chip->chip_shift);
2043 	chip->select_chip(mtd, chipnr);
2044 
2045 	/* Shift to get page */
2046 	realpage = (int)(from >> chip->page_shift);
2047 	page = realpage & chip->pagemask;
2048 
2049 	while (1) {
2050 		WATCHDOG_RESET();
2051 
2052 		if (ops->mode == MTD_OPS_RAW)
2053 			ret = chip->ecc.read_oob_raw(mtd, chip, page);
2054 		else
2055 			ret = chip->ecc.read_oob(mtd, chip, page);
2056 
2057 		if (ret < 0)
2058 			break;
2059 
2060 		len = min(len, readlen);
2061 		buf = nand_transfer_oob(chip, buf, ops, len);
2062 
2063 		if (chip->options & NAND_NEED_READRDY) {
2064 			/* Apply delay or wait for ready/busy pin */
2065 			if (!chip->dev_ready)
2066 				udelay(chip->chip_delay);
2067 			else
2068 				nand_wait_ready(mtd);
2069 		}
2070 
2071 		readlen -= len;
2072 		if (!readlen)
2073 			break;
2074 
2075 		/* Increment page address */
2076 		realpage++;
2077 
2078 		page = realpage & chip->pagemask;
2079 		/* Check, if we cross a chip boundary */
2080 		if (!page) {
2081 			chipnr++;
2082 			chip->select_chip(mtd, -1);
2083 			chip->select_chip(mtd, chipnr);
2084 		}
2085 	}
2086 	chip->select_chip(mtd, -1);
2087 
2088 	ops->oobretlen = ops->ooblen - readlen;
2089 
2090 	if (ret < 0)
2091 		return ret;
2092 
2093 	if (mtd->ecc_stats.failed - stats.failed)
2094 		return -EBADMSG;
2095 
2096 	return  mtd->ecc_stats.corrected - stats.corrected ? -EUCLEAN : 0;
2097 }
2098 
2099 /**
2100  * nand_read_oob - [MTD Interface] NAND read data and/or out-of-band
2101  * @mtd: MTD device structure
2102  * @from: offset to read from
2103  * @ops: oob operation description structure
2104  *
2105  * NAND read data and/or out-of-band data.
2106  */
2107 static int nand_read_oob(struct mtd_info *mtd, loff_t from,
2108 			 struct mtd_oob_ops *ops)
2109 {
2110 	int ret = -ENOTSUPP;
2111 
2112 	ops->retlen = 0;
2113 
2114 	/* Do not allow reads past end of device */
2115 	if (ops->datbuf && (from + ops->len) > mtd->size) {
2116 		pr_debug("%s: attempt to read beyond end of device\n",
2117 				__func__);
2118 		return -EINVAL;
2119 	}
2120 
2121 	nand_get_device(mtd, FL_READING);
2122 
2123 	switch (ops->mode) {
2124 	case MTD_OPS_PLACE_OOB:
2125 	case MTD_OPS_AUTO_OOB:
2126 	case MTD_OPS_RAW:
2127 		break;
2128 
2129 	default:
2130 		goto out;
2131 	}
2132 
2133 	if (!ops->datbuf)
2134 		ret = nand_do_read_oob(mtd, from, ops);
2135 	else
2136 		ret = nand_do_read_ops(mtd, from, ops);
2137 
2138 out:
2139 	nand_release_device(mtd);
2140 	return ret;
2141 }
2142 
2143 
2144 /**
2145  * nand_write_page_raw - [INTERN] raw page write function
2146  * @mtd: mtd info structure
2147  * @chip: nand chip info structure
2148  * @buf: data buffer
2149  * @oob_required: must write chip->oob_poi to OOB
2150  * @page: page number to write
2151  *
2152  * Not for syndrome calculating ECC controllers, which use a special oob layout.
2153  */
2154 static int nand_write_page_raw(struct mtd_info *mtd, struct nand_chip *chip,
2155 			       const uint8_t *buf, int oob_required, int page)
2156 {
2157 	chip->write_buf(mtd, buf, mtd->writesize);
2158 	if (oob_required)
2159 		chip->write_buf(mtd, chip->oob_poi, mtd->oobsize);
2160 
2161 	return 0;
2162 }
2163 
2164 /**
2165  * nand_write_page_raw_syndrome - [INTERN] raw page write function
2166  * @mtd: mtd info structure
2167  * @chip: nand chip info structure
2168  * @buf: data buffer
2169  * @oob_required: must write chip->oob_poi to OOB
2170  * @page: page number to write
2171  *
2172  * We need a special oob layout and handling even when ECC isn't checked.
2173  */
2174 static int nand_write_page_raw_syndrome(struct mtd_info *mtd,
2175 					struct nand_chip *chip,
2176 					const uint8_t *buf, int oob_required,
2177 					int page)
2178 {
2179 	int eccsize = chip->ecc.size;
2180 	int eccbytes = chip->ecc.bytes;
2181 	uint8_t *oob = chip->oob_poi;
2182 	int steps, size;
2183 
2184 	for (steps = chip->ecc.steps; steps > 0; steps--) {
2185 		chip->write_buf(mtd, buf, eccsize);
2186 		buf += eccsize;
2187 
2188 		if (chip->ecc.prepad) {
2189 			chip->write_buf(mtd, oob, chip->ecc.prepad);
2190 			oob += chip->ecc.prepad;
2191 		}
2192 
2193 		chip->write_buf(mtd, oob, eccbytes);
2194 		oob += eccbytes;
2195 
2196 		if (chip->ecc.postpad) {
2197 			chip->write_buf(mtd, oob, chip->ecc.postpad);
2198 			oob += chip->ecc.postpad;
2199 		}
2200 	}
2201 
2202 	size = mtd->oobsize - (oob - chip->oob_poi);
2203 	if (size)
2204 		chip->write_buf(mtd, oob, size);
2205 
2206 	return 0;
2207 }
2208 /**
2209  * nand_write_page_swecc - [REPLACEABLE] software ECC based page write function
2210  * @mtd: mtd info structure
2211  * @chip: nand chip info structure
2212  * @buf: data buffer
2213  * @oob_required: must write chip->oob_poi to OOB
2214  * @page: page number to write
2215  */
2216 static int nand_write_page_swecc(struct mtd_info *mtd, struct nand_chip *chip,
2217 				 const uint8_t *buf, int oob_required,
2218 				 int page)
2219 {
2220 	int i, eccsize = chip->ecc.size;
2221 	int eccbytes = chip->ecc.bytes;
2222 	int eccsteps = chip->ecc.steps;
2223 	uint8_t *ecc_calc = chip->buffers->ecccalc;
2224 	const uint8_t *p = buf;
2225 	uint32_t *eccpos = chip->ecc.layout->eccpos;
2226 
2227 	/* Software ECC calculation */
2228 	for (i = 0; eccsteps; eccsteps--, i += eccbytes, p += eccsize)
2229 		chip->ecc.calculate(mtd, p, &ecc_calc[i]);
2230 
2231 	for (i = 0; i < chip->ecc.total; i++)
2232 		chip->oob_poi[eccpos[i]] = ecc_calc[i];
2233 
2234 	return chip->ecc.write_page_raw(mtd, chip, buf, 1, page);
2235 }
2236 
2237 /**
2238  * nand_write_page_hwecc - [REPLACEABLE] hardware ECC based page write function
2239  * @mtd: mtd info structure
2240  * @chip: nand chip info structure
2241  * @buf: data buffer
2242  * @oob_required: must write chip->oob_poi to OOB
2243  * @page: page number to write
2244  */
2245 static int nand_write_page_hwecc(struct mtd_info *mtd, struct nand_chip *chip,
2246 				  const uint8_t *buf, int oob_required,
2247 				  int page)
2248 {
2249 	int i, eccsize = chip->ecc.size;
2250 	int eccbytes = chip->ecc.bytes;
2251 	int eccsteps = chip->ecc.steps;
2252 	uint8_t *ecc_calc = chip->buffers->ecccalc;
2253 	const uint8_t *p = buf;
2254 	uint32_t *eccpos = chip->ecc.layout->eccpos;
2255 
2256 	for (i = 0; eccsteps; eccsteps--, i += eccbytes, p += eccsize) {
2257 		chip->ecc.hwctl(mtd, NAND_ECC_WRITE);
2258 		chip->write_buf(mtd, p, eccsize);
2259 		chip->ecc.calculate(mtd, p, &ecc_calc[i]);
2260 	}
2261 
2262 	for (i = 0; i < chip->ecc.total; i++)
2263 		chip->oob_poi[eccpos[i]] = ecc_calc[i];
2264 
2265 	chip->write_buf(mtd, chip->oob_poi, mtd->oobsize);
2266 
2267 	return 0;
2268 }
2269 
2270 
2271 /**
2272  * nand_write_subpage_hwecc - [REPLACEABLE] hardware ECC based subpage write
2273  * @mtd:	mtd info structure
2274  * @chip:	nand chip info structure
2275  * @offset:	column address of subpage within the page
2276  * @data_len:	data length
2277  * @buf:	data buffer
2278  * @oob_required: must write chip->oob_poi to OOB
2279  * @page: page number to write
2280  */
2281 static int nand_write_subpage_hwecc(struct mtd_info *mtd,
2282 				struct nand_chip *chip, uint32_t offset,
2283 				uint32_t data_len, const uint8_t *buf,
2284 				int oob_required, int page)
2285 {
2286 	uint8_t *oob_buf  = chip->oob_poi;
2287 	uint8_t *ecc_calc = chip->buffers->ecccalc;
2288 	int ecc_size      = chip->ecc.size;
2289 	int ecc_bytes     = chip->ecc.bytes;
2290 	int ecc_steps     = chip->ecc.steps;
2291 	uint32_t *eccpos  = chip->ecc.layout->eccpos;
2292 	uint32_t start_step = offset / ecc_size;
2293 	uint32_t end_step   = (offset + data_len - 1) / ecc_size;
2294 	int oob_bytes       = mtd->oobsize / ecc_steps;
2295 	int step, i;
2296 
2297 	for (step = 0; step < ecc_steps; step++) {
2298 		/* configure controller for WRITE access */
2299 		chip->ecc.hwctl(mtd, NAND_ECC_WRITE);
2300 
2301 		/* write data (untouched subpages already masked by 0xFF) */
2302 		chip->write_buf(mtd, buf, ecc_size);
2303 
2304 		/* mask ECC of un-touched subpages by padding 0xFF */
2305 		if ((step < start_step) || (step > end_step))
2306 			memset(ecc_calc, 0xff, ecc_bytes);
2307 		else
2308 			chip->ecc.calculate(mtd, buf, ecc_calc);
2309 
2310 		/* mask OOB of un-touched subpages by padding 0xFF */
2311 		/* if oob_required, preserve OOB metadata of written subpage */
2312 		if (!oob_required || (step < start_step) || (step > end_step))
2313 			memset(oob_buf, 0xff, oob_bytes);
2314 
2315 		buf += ecc_size;
2316 		ecc_calc += ecc_bytes;
2317 		oob_buf  += oob_bytes;
2318 	}
2319 
2320 	/* copy calculated ECC for whole page to chip->buffer->oob */
2321 	/* this include masked-value(0xFF) for unwritten subpages */
2322 	ecc_calc = chip->buffers->ecccalc;
2323 	for (i = 0; i < chip->ecc.total; i++)
2324 		chip->oob_poi[eccpos[i]] = ecc_calc[i];
2325 
2326 	/* write OOB buffer to NAND device */
2327 	chip->write_buf(mtd, chip->oob_poi, mtd->oobsize);
2328 
2329 	return 0;
2330 }
2331 
2332 
2333 /**
2334  * nand_write_page_syndrome - [REPLACEABLE] hardware ECC syndrome based page write
2335  * @mtd: mtd info structure
2336  * @chip: nand chip info structure
2337  * @buf: data buffer
2338  * @oob_required: must write chip->oob_poi to OOB
2339  * @page: page number to write
2340  *
2341  * The hw generator calculates the error syndrome automatically. Therefore we
2342  * need a special oob layout and handling.
2343  */
2344 static int nand_write_page_syndrome(struct mtd_info *mtd,
2345 				    struct nand_chip *chip,
2346 				    const uint8_t *buf, int oob_required,
2347 				    int page)
2348 {
2349 	int i, eccsize = chip->ecc.size;
2350 	int eccbytes = chip->ecc.bytes;
2351 	int eccsteps = chip->ecc.steps;
2352 	const uint8_t *p = buf;
2353 	uint8_t *oob = chip->oob_poi;
2354 
2355 	for (i = 0; eccsteps; eccsteps--, i += eccbytes, p += eccsize) {
2356 
2357 		chip->ecc.hwctl(mtd, NAND_ECC_WRITE);
2358 		chip->write_buf(mtd, p, eccsize);
2359 
2360 		if (chip->ecc.prepad) {
2361 			chip->write_buf(mtd, oob, chip->ecc.prepad);
2362 			oob += chip->ecc.prepad;
2363 		}
2364 
2365 		chip->ecc.calculate(mtd, p, oob);
2366 		chip->write_buf(mtd, oob, eccbytes);
2367 		oob += eccbytes;
2368 
2369 		if (chip->ecc.postpad) {
2370 			chip->write_buf(mtd, oob, chip->ecc.postpad);
2371 			oob += chip->ecc.postpad;
2372 		}
2373 	}
2374 
2375 	/* Calculate remaining oob bytes */
2376 	i = mtd->oobsize - (oob - chip->oob_poi);
2377 	if (i)
2378 		chip->write_buf(mtd, oob, i);
2379 
2380 	return 0;
2381 }
2382 
2383 /**
2384  * nand_write_page - [REPLACEABLE] write one page
2385  * @mtd: MTD device structure
2386  * @chip: NAND chip descriptor
2387  * @offset: address offset within the page
2388  * @data_len: length of actual data to be written
2389  * @buf: the data to write
2390  * @oob_required: must write chip->oob_poi to OOB
2391  * @page: page number to write
2392  * @raw: use _raw version of write_page
2393  */
2394 static int nand_write_page(struct mtd_info *mtd, struct nand_chip *chip,
2395 		uint32_t offset, int data_len, const uint8_t *buf,
2396 		int oob_required, int page, int raw)
2397 {
2398 	int status, subpage;
2399 
2400 	if (!(chip->options & NAND_NO_SUBPAGE_WRITE) &&
2401 		chip->ecc.write_subpage)
2402 		subpage = offset || (data_len < mtd->writesize);
2403 	else
2404 		subpage = 0;
2405 
2406 	if (nand_standard_page_accessors(&chip->ecc))
2407 		chip->cmdfunc(mtd, NAND_CMD_SEQIN, 0x00, page);
2408 
2409 	if (unlikely(raw))
2410 		status = chip->ecc.write_page_raw(mtd, chip, buf,
2411 						  oob_required, page);
2412 	else if (subpage)
2413 		status = chip->ecc.write_subpage(mtd, chip, offset, data_len,
2414 						 buf, oob_required, page);
2415 	else
2416 		status = chip->ecc.write_page(mtd, chip, buf, oob_required,
2417 					      page);
2418 
2419 	if (status < 0)
2420 		return status;
2421 
2422 	if (nand_standard_page_accessors(&chip->ecc)) {
2423 		chip->cmdfunc(mtd, NAND_CMD_PAGEPROG, -1, -1);
2424 
2425 		status = chip->waitfunc(mtd, chip);
2426 		if (status & NAND_STATUS_FAIL)
2427 			return -EIO;
2428 	}
2429 
2430 	return 0;
2431 }
2432 
2433 /**
2434  * nand_fill_oob - [INTERN] Transfer client buffer to oob
2435  * @mtd: MTD device structure
2436  * @oob: oob data buffer
2437  * @len: oob data write length
2438  * @ops: oob ops structure
2439  */
2440 static uint8_t *nand_fill_oob(struct mtd_info *mtd, uint8_t *oob, size_t len,
2441 			      struct mtd_oob_ops *ops)
2442 {
2443 	struct nand_chip *chip = mtd_to_nand(mtd);
2444 
2445 	/*
2446 	 * Initialise to all 0xFF, to avoid the possibility of left over OOB
2447 	 * data from a previous OOB read.
2448 	 */
2449 	memset(chip->oob_poi, 0xff, mtd->oobsize);
2450 
2451 	switch (ops->mode) {
2452 
2453 	case MTD_OPS_PLACE_OOB:
2454 	case MTD_OPS_RAW:
2455 		memcpy(chip->oob_poi + ops->ooboffs, oob, len);
2456 		return oob + len;
2457 
2458 	case MTD_OPS_AUTO_OOB: {
2459 		struct nand_oobfree *free = chip->ecc.layout->oobfree;
2460 		uint32_t boffs = 0, woffs = ops->ooboffs;
2461 		size_t bytes = 0;
2462 
2463 		for (; free->length && len; free++, len -= bytes) {
2464 			/* Write request not from offset 0? */
2465 			if (unlikely(woffs)) {
2466 				if (woffs >= free->length) {
2467 					woffs -= free->length;
2468 					continue;
2469 				}
2470 				boffs = free->offset + woffs;
2471 				bytes = min_t(size_t, len,
2472 					      (free->length - woffs));
2473 				woffs = 0;
2474 			} else {
2475 				bytes = min_t(size_t, len, free->length);
2476 				boffs = free->offset;
2477 			}
2478 			memcpy(chip->oob_poi + boffs, oob, bytes);
2479 			oob += bytes;
2480 		}
2481 		return oob;
2482 	}
2483 	default:
2484 		BUG();
2485 	}
2486 	return NULL;
2487 }
2488 
2489 #define NOTALIGNED(x)	((x & (chip->subpagesize - 1)) != 0)
2490 
2491 /**
2492  * nand_do_write_ops - [INTERN] NAND write with ECC
2493  * @mtd: MTD device structure
2494  * @to: offset to write to
2495  * @ops: oob operations description structure
2496  *
2497  * NAND write with ECC.
2498  */
2499 static int nand_do_write_ops(struct mtd_info *mtd, loff_t to,
2500 			     struct mtd_oob_ops *ops)
2501 {
2502 	int chipnr, realpage, page, column;
2503 	struct nand_chip *chip = mtd_to_nand(mtd);
2504 	uint32_t writelen = ops->len;
2505 
2506 	uint32_t oobwritelen = ops->ooblen;
2507 	uint32_t oobmaxlen = mtd_oobavail(mtd, ops);
2508 
2509 	uint8_t *oob = ops->oobbuf;
2510 	uint8_t *buf = ops->datbuf;
2511 	int ret;
2512 	int oob_required = oob ? 1 : 0;
2513 
2514 	ops->retlen = 0;
2515 	if (!writelen)
2516 		return 0;
2517 
2518 	/* Reject writes, which are not page aligned */
2519 	if (NOTALIGNED(to)) {
2520 		pr_notice("%s: attempt to write non page aligned data\n",
2521 			   __func__);
2522 		return -EINVAL;
2523 	}
2524 
2525 	column = to & (mtd->writesize - 1);
2526 
2527 	chipnr = (int)(to >> chip->chip_shift);
2528 	chip->select_chip(mtd, chipnr);
2529 
2530 	/* Check, if it is write protected */
2531 	if (nand_check_wp(mtd)) {
2532 		ret = -EIO;
2533 		goto err_out;
2534 	}
2535 
2536 	realpage = (int)(to >> chip->page_shift);
2537 	page = realpage & chip->pagemask;
2538 
2539 	/* Invalidate the page cache, when we write to the cached page */
2540 	if (to <= ((loff_t)chip->pagebuf << chip->page_shift) &&
2541 	    ((loff_t)chip->pagebuf << chip->page_shift) < (to + ops->len))
2542 		chip->pagebuf = -1;
2543 
2544 	/* Don't allow multipage oob writes with offset */
2545 	if (oob && ops->ooboffs && (ops->ooboffs + ops->ooblen > oobmaxlen)) {
2546 		ret = -EINVAL;
2547 		goto err_out;
2548 	}
2549 
2550 	while (1) {
2551 		int bytes = mtd->writesize;
2552 		uint8_t *wbuf = buf;
2553 		int use_bufpoi;
2554 		int part_pagewr = (column || writelen < mtd->writesize);
2555 
2556 		if (part_pagewr)
2557 			use_bufpoi = 1;
2558 		else if (chip->options & NAND_USE_BOUNCE_BUFFER)
2559 			use_bufpoi = !IS_ALIGNED((unsigned long)buf,
2560 						 chip->buf_align);
2561 		else
2562 			use_bufpoi = 0;
2563 
2564 		WATCHDOG_RESET();
2565 		/* Partial page write?, or need to use bounce buffer */
2566 		if (use_bufpoi) {
2567 			pr_debug("%s: using write bounce buffer for buf@%p\n",
2568 					 __func__, buf);
2569 			if (part_pagewr)
2570 				bytes = min_t(int, bytes - column, writelen);
2571 			chip->pagebuf = -1;
2572 			memset(chip->buffers->databuf, 0xff, mtd->writesize);
2573 			memcpy(&chip->buffers->databuf[column], buf, bytes);
2574 			wbuf = chip->buffers->databuf;
2575 		}
2576 
2577 		if (unlikely(oob)) {
2578 			size_t len = min(oobwritelen, oobmaxlen);
2579 			oob = nand_fill_oob(mtd, oob, len, ops);
2580 			oobwritelen -= len;
2581 		} else {
2582 			/* We still need to erase leftover OOB data */
2583 			memset(chip->oob_poi, 0xff, mtd->oobsize);
2584 		}
2585 		ret = chip->write_page(mtd, chip, column, bytes, wbuf,
2586 					oob_required, page,
2587 					(ops->mode == MTD_OPS_RAW));
2588 		if (ret)
2589 			break;
2590 
2591 		writelen -= bytes;
2592 		if (!writelen)
2593 			break;
2594 
2595 		column = 0;
2596 		buf += bytes;
2597 		realpage++;
2598 
2599 		page = realpage & chip->pagemask;
2600 		/* Check, if we cross a chip boundary */
2601 		if (!page) {
2602 			chipnr++;
2603 			chip->select_chip(mtd, -1);
2604 			chip->select_chip(mtd, chipnr);
2605 		}
2606 	}
2607 
2608 	ops->retlen = ops->len - writelen;
2609 	if (unlikely(oob))
2610 		ops->oobretlen = ops->ooblen;
2611 
2612 err_out:
2613 	chip->select_chip(mtd, -1);
2614 	return ret;
2615 }
2616 
2617 /**
2618  * panic_nand_write - [MTD Interface] NAND write with ECC
2619  * @mtd: MTD device structure
2620  * @to: offset to write to
2621  * @len: number of bytes to write
2622  * @retlen: pointer to variable to store the number of written bytes
2623  * @buf: the data to write
2624  *
2625  * NAND write with ECC. Used when performing writes in interrupt context, this
2626  * may for example be called by mtdoops when writing an oops while in panic.
2627  */
2628 static int panic_nand_write(struct mtd_info *mtd, loff_t to, size_t len,
2629 			    size_t *retlen, const uint8_t *buf)
2630 {
2631 	struct nand_chip *chip = mtd_to_nand(mtd);
2632 	struct mtd_oob_ops ops;
2633 	int ret;
2634 
2635 	/* Wait for the device to get ready */
2636 	panic_nand_wait(mtd, chip, 400);
2637 
2638 	/* Grab the device */
2639 	panic_nand_get_device(chip, mtd, FL_WRITING);
2640 
2641 	memset(&ops, 0, sizeof(ops));
2642 	ops.len = len;
2643 	ops.datbuf = (uint8_t *)buf;
2644 	ops.mode = MTD_OPS_PLACE_OOB;
2645 
2646 	ret = nand_do_write_ops(mtd, to, &ops);
2647 
2648 	*retlen = ops.retlen;
2649 	return ret;
2650 }
2651 
2652 /**
2653  * nand_do_write_oob - [MTD Interface] NAND write out-of-band
2654  * @mtd: MTD device structure
2655  * @to: offset to write to
2656  * @ops: oob operation description structure
2657  *
2658  * NAND write out-of-band.
2659  */
2660 static int nand_do_write_oob(struct mtd_info *mtd, loff_t to,
2661 			     struct mtd_oob_ops *ops)
2662 {
2663 	int chipnr, page, status, len;
2664 	struct nand_chip *chip = mtd_to_nand(mtd);
2665 
2666 	pr_debug("%s: to = 0x%08x, len = %i\n",
2667 			 __func__, (unsigned int)to, (int)ops->ooblen);
2668 
2669 	len = mtd_oobavail(mtd, ops);
2670 
2671 	/* Do not allow write past end of page */
2672 	if ((ops->ooboffs + ops->ooblen) > len) {
2673 		pr_debug("%s: attempt to write past end of page\n",
2674 				__func__);
2675 		return -EINVAL;
2676 	}
2677 
2678 	if (unlikely(ops->ooboffs >= len)) {
2679 		pr_debug("%s: attempt to start write outside oob\n",
2680 				__func__);
2681 		return -EINVAL;
2682 	}
2683 
2684 	/* Do not allow write past end of device */
2685 	if (unlikely(to >= mtd->size ||
2686 		     ops->ooboffs + ops->ooblen >
2687 			((mtd->size >> chip->page_shift) -
2688 			 (to >> chip->page_shift)) * len)) {
2689 		pr_debug("%s: attempt to write beyond end of device\n",
2690 				__func__);
2691 		return -EINVAL;
2692 	}
2693 
2694 	chipnr = (int)(to >> chip->chip_shift);
2695 
2696 	/*
2697 	 * Reset the chip. Some chips (like the Toshiba TC5832DC found in one
2698 	 * of my DiskOnChip 2000 test units) will clear the whole data page too
2699 	 * if we don't do this. I have no clue why, but I seem to have 'fixed'
2700 	 * it in the doc2000 driver in August 1999.  dwmw2.
2701 	 */
2702 	nand_reset(chip, chipnr);
2703 
2704 	chip->select_chip(mtd, chipnr);
2705 
2706 	/* Shift to get page */
2707 	page = (int)(to >> chip->page_shift);
2708 
2709 	/* Check, if it is write protected */
2710 	if (nand_check_wp(mtd)) {
2711 		chip->select_chip(mtd, -1);
2712 		return -EROFS;
2713 	}
2714 
2715 	/* Invalidate the page cache, if we write to the cached page */
2716 	if (page == chip->pagebuf)
2717 		chip->pagebuf = -1;
2718 
2719 	nand_fill_oob(mtd, ops->oobbuf, ops->ooblen, ops);
2720 
2721 	if (ops->mode == MTD_OPS_RAW)
2722 		status = chip->ecc.write_oob_raw(mtd, chip, page & chip->pagemask);
2723 	else
2724 		status = chip->ecc.write_oob(mtd, chip, page & chip->pagemask);
2725 
2726 	chip->select_chip(mtd, -1);
2727 
2728 	if (status)
2729 		return status;
2730 
2731 	ops->oobretlen = ops->ooblen;
2732 
2733 	return 0;
2734 }
2735 
2736 /**
2737  * nand_write_oob - [MTD Interface] NAND write data and/or out-of-band
2738  * @mtd: MTD device structure
2739  * @to: offset to write to
2740  * @ops: oob operation description structure
2741  */
2742 static int nand_write_oob(struct mtd_info *mtd, loff_t to,
2743 			  struct mtd_oob_ops *ops)
2744 {
2745 	int ret = -ENOTSUPP;
2746 
2747 	ops->retlen = 0;
2748 
2749 	/* Do not allow writes past end of device */
2750 	if (ops->datbuf && (to + ops->len) > mtd->size) {
2751 		pr_debug("%s: attempt to write beyond end of device\n",
2752 				__func__);
2753 		return -EINVAL;
2754 	}
2755 
2756 	nand_get_device(mtd, FL_WRITING);
2757 
2758 	switch (ops->mode) {
2759 	case MTD_OPS_PLACE_OOB:
2760 	case MTD_OPS_AUTO_OOB:
2761 	case MTD_OPS_RAW:
2762 		break;
2763 
2764 	default:
2765 		goto out;
2766 	}
2767 
2768 	if (!ops->datbuf)
2769 		ret = nand_do_write_oob(mtd, to, ops);
2770 	else
2771 		ret = nand_do_write_ops(mtd, to, ops);
2772 
2773 out:
2774 	nand_release_device(mtd);
2775 	return ret;
2776 }
2777 
2778 /**
2779  * single_erase - [GENERIC] NAND standard block erase command function
2780  * @mtd: MTD device structure
2781  * @page: the page address of the block which will be erased
2782  *
2783  * Standard erase command for NAND chips. Returns NAND status.
2784  */
2785 static int single_erase(struct mtd_info *mtd, int page)
2786 {
2787 	struct nand_chip *chip = mtd_to_nand(mtd);
2788 	/* Send commands to erase a block */
2789 	chip->cmdfunc(mtd, NAND_CMD_ERASE1, -1, page);
2790 	chip->cmdfunc(mtd, NAND_CMD_ERASE2, -1, -1);
2791 
2792 	return chip->waitfunc(mtd, chip);
2793 }
2794 
2795 /**
2796  * nand_erase - [MTD Interface] erase block(s)
2797  * @mtd: MTD device structure
2798  * @instr: erase instruction
2799  *
2800  * Erase one ore more blocks.
2801  */
2802 static int nand_erase(struct mtd_info *mtd, struct erase_info *instr)
2803 {
2804 	return nand_erase_nand(mtd, instr, 0);
2805 }
2806 
2807 /**
2808  * nand_erase_nand - [INTERN] erase block(s)
2809  * @mtd: MTD device structure
2810  * @instr: erase instruction
2811  * @allowbbt: allow erasing the bbt area
2812  *
2813  * Erase one ore more blocks.
2814  */
2815 int nand_erase_nand(struct mtd_info *mtd, struct erase_info *instr,
2816 		    int allowbbt)
2817 {
2818 	int page, status, pages_per_block, ret, chipnr;
2819 	struct nand_chip *chip = mtd_to_nand(mtd);
2820 	loff_t len;
2821 
2822 	pr_debug("%s: start = 0x%012llx, len = %llu\n",
2823 			__func__, (unsigned long long)instr->addr,
2824 			(unsigned long long)instr->len);
2825 
2826 	if (check_offs_len(mtd, instr->addr, instr->len))
2827 		return -EINVAL;
2828 
2829 	/* Grab the lock and see if the device is available */
2830 	nand_get_device(mtd, FL_ERASING);
2831 
2832 	/* Shift to get first page */
2833 	page = (int)(instr->addr >> chip->page_shift);
2834 	chipnr = (int)(instr->addr >> chip->chip_shift);
2835 
2836 	/* Calculate pages in each block */
2837 	pages_per_block = 1 << (chip->phys_erase_shift - chip->page_shift);
2838 
2839 	/* Select the NAND device */
2840 	chip->select_chip(mtd, chipnr);
2841 
2842 	/* Check, if it is write protected */
2843 	if (nand_check_wp(mtd)) {
2844 		pr_debug("%s: device is write protected!\n",
2845 				__func__);
2846 		instr->state = MTD_ERASE_FAILED;
2847 		goto erase_exit;
2848 	}
2849 
2850 	/* Loop through the pages */
2851 	len = instr->len;
2852 
2853 	instr->state = MTD_ERASING;
2854 
2855 	while (len) {
2856 		WATCHDOG_RESET();
2857 
2858 		/* Check if we have a bad block, we do not erase bad blocks! */
2859 		if (!instr->scrub && nand_block_checkbad(mtd, ((loff_t) page) <<
2860 					chip->page_shift, allowbbt)) {
2861 			pr_warn("%s: attempt to erase a bad block at page 0x%08x\n",
2862 				    __func__, page);
2863 			instr->state = MTD_ERASE_FAILED;
2864 			goto erase_exit;
2865 		}
2866 
2867 		/*
2868 		 * Invalidate the page cache, if we erase the block which
2869 		 * contains the current cached page.
2870 		 */
2871 		if (page <= chip->pagebuf && chip->pagebuf <
2872 		    (page + pages_per_block))
2873 			chip->pagebuf = -1;
2874 
2875 		status = chip->erase(mtd, page & chip->pagemask);
2876 
2877 		/* See if block erase succeeded */
2878 		if (status & NAND_STATUS_FAIL) {
2879 			pr_debug("%s: failed erase, page 0x%08x\n",
2880 					__func__, page);
2881 			instr->state = MTD_ERASE_FAILED;
2882 			instr->fail_addr =
2883 				((loff_t)page << chip->page_shift);
2884 			goto erase_exit;
2885 		}
2886 
2887 		/* Increment page address and decrement length */
2888 		len -= (1ULL << chip->phys_erase_shift);
2889 		page += pages_per_block;
2890 
2891 		/* Check, if we cross a chip boundary */
2892 		if (len && !(page & chip->pagemask)) {
2893 			chipnr++;
2894 			chip->select_chip(mtd, -1);
2895 			chip->select_chip(mtd, chipnr);
2896 		}
2897 	}
2898 	instr->state = MTD_ERASE_DONE;
2899 
2900 erase_exit:
2901 
2902 	ret = instr->state == MTD_ERASE_DONE ? 0 : -EIO;
2903 
2904 	/* Deselect and wake up anyone waiting on the device */
2905 	chip->select_chip(mtd, -1);
2906 	nand_release_device(mtd);
2907 
2908 	/* Do call back function */
2909 	if (!ret)
2910 		mtd_erase_callback(instr);
2911 
2912 	/* Return more or less happy */
2913 	return ret;
2914 }
2915 
2916 /**
2917  * nand_sync - [MTD Interface] sync
2918  * @mtd: MTD device structure
2919  *
2920  * Sync is actually a wait for chip ready function.
2921  */
2922 static void nand_sync(struct mtd_info *mtd)
2923 {
2924 	pr_debug("%s: called\n", __func__);
2925 
2926 	/* Grab the lock and see if the device is available */
2927 	nand_get_device(mtd, FL_SYNCING);
2928 	/* Release it and go back */
2929 	nand_release_device(mtd);
2930 }
2931 
2932 /**
2933  * nand_block_isbad - [MTD Interface] Check if block at offset is bad
2934  * @mtd: MTD device structure
2935  * @offs: offset relative to mtd start
2936  */
2937 static int nand_block_isbad(struct mtd_info *mtd, loff_t offs)
2938 {
2939 	struct nand_chip *chip = mtd_to_nand(mtd);
2940 	int chipnr = (int)(offs >> chip->chip_shift);
2941 	int ret;
2942 
2943 	/* Select the NAND device */
2944 	nand_get_device(mtd, FL_READING);
2945 	chip->select_chip(mtd, chipnr);
2946 
2947 	ret = nand_block_checkbad(mtd, offs, 0);
2948 
2949 	chip->select_chip(mtd, -1);
2950 	nand_release_device(mtd);
2951 
2952 	return ret;
2953 }
2954 
2955 /**
2956  * nand_block_markbad - [MTD Interface] Mark block at the given offset as bad
2957  * @mtd: MTD device structure
2958  * @ofs: offset relative to mtd start
2959  */
2960 static int nand_block_markbad(struct mtd_info *mtd, loff_t ofs)
2961 {
2962 	int ret;
2963 
2964 	ret = nand_block_isbad(mtd, ofs);
2965 	if (ret) {
2966 		/* If it was bad already, return success and do nothing */
2967 		if (ret > 0)
2968 			return 0;
2969 		return ret;
2970 	}
2971 
2972 	return nand_block_markbad_lowlevel(mtd, ofs);
2973 }
2974 
2975 /**
2976  * nand_onfi_set_features- [REPLACEABLE] set features for ONFI nand
2977  * @mtd: MTD device structure
2978  * @chip: nand chip info structure
2979  * @addr: feature address.
2980  * @subfeature_param: the subfeature parameters, a four bytes array.
2981  */
2982 static int nand_onfi_set_features(struct mtd_info *mtd, struct nand_chip *chip,
2983 			int addr, uint8_t *subfeature_param)
2984 {
2985 	int status;
2986 	int i;
2987 
2988 #ifdef CONFIG_SYS_NAND_ONFI_DETECTION
2989 	if (!chip->onfi_version ||
2990 	    !(le16_to_cpu(chip->onfi_params.opt_cmd)
2991 	      & ONFI_OPT_CMD_SET_GET_FEATURES))
2992 		return -ENOTSUPP;
2993 #endif
2994 
2995 	chip->cmdfunc(mtd, NAND_CMD_SET_FEATURES, addr, -1);
2996 	for (i = 0; i < ONFI_SUBFEATURE_PARAM_LEN; ++i)
2997 		chip->write_byte(mtd, subfeature_param[i]);
2998 
2999 	status = chip->waitfunc(mtd, chip);
3000 	if (status & NAND_STATUS_FAIL)
3001 		return -EIO;
3002 	return 0;
3003 }
3004 
3005 /**
3006  * nand_onfi_get_features- [REPLACEABLE] get features for ONFI nand
3007  * @mtd: MTD device structure
3008  * @chip: nand chip info structure
3009  * @addr: feature address.
3010  * @subfeature_param: the subfeature parameters, a four bytes array.
3011  */
3012 static int nand_onfi_get_features(struct mtd_info *mtd, struct nand_chip *chip,
3013 			int addr, uint8_t *subfeature_param)
3014 {
3015 	int i;
3016 
3017 #ifdef CONFIG_SYS_NAND_ONFI_DETECTION
3018 	if (!chip->onfi_version ||
3019 	    !(le16_to_cpu(chip->onfi_params.opt_cmd)
3020 	      & ONFI_OPT_CMD_SET_GET_FEATURES))
3021 		return -ENOTSUPP;
3022 #endif
3023 
3024 	chip->cmdfunc(mtd, NAND_CMD_GET_FEATURES, addr, -1);
3025 	for (i = 0; i < ONFI_SUBFEATURE_PARAM_LEN; ++i)
3026 		*subfeature_param++ = chip->read_byte(mtd);
3027 	return 0;
3028 }
3029 
3030 /* Set default functions */
3031 static void nand_set_defaults(struct nand_chip *chip, int busw)
3032 {
3033 	/* check for proper chip_delay setup, set 20us if not */
3034 	if (!chip->chip_delay)
3035 		chip->chip_delay = 20;
3036 
3037 	/* check, if a user supplied command function given */
3038 	if (chip->cmdfunc == NULL)
3039 		chip->cmdfunc = nand_command;
3040 
3041 	/* check, if a user supplied wait function given */
3042 	if (chip->waitfunc == NULL)
3043 		chip->waitfunc = nand_wait;
3044 
3045 	if (!chip->select_chip)
3046 		chip->select_chip = nand_select_chip;
3047 
3048 	/* set for ONFI nand */
3049 	if (!chip->onfi_set_features)
3050 		chip->onfi_set_features = nand_onfi_set_features;
3051 	if (!chip->onfi_get_features)
3052 		chip->onfi_get_features = nand_onfi_get_features;
3053 
3054 	/* If called twice, pointers that depend on busw may need to be reset */
3055 	if (!chip->read_byte || chip->read_byte == nand_read_byte)
3056 		chip->read_byte = busw ? nand_read_byte16 : nand_read_byte;
3057 	if (!chip->read_word)
3058 		chip->read_word = nand_read_word;
3059 	if (!chip->block_bad)
3060 		chip->block_bad = nand_block_bad;
3061 	if (!chip->block_markbad)
3062 		chip->block_markbad = nand_default_block_markbad;
3063 	if (!chip->write_buf || chip->write_buf == nand_write_buf)
3064 		chip->write_buf = busw ? nand_write_buf16 : nand_write_buf;
3065 	if (!chip->write_byte || chip->write_byte == nand_write_byte)
3066 		chip->write_byte = busw ? nand_write_byte16 : nand_write_byte;
3067 	if (!chip->read_buf || chip->read_buf == nand_read_buf)
3068 		chip->read_buf = busw ? nand_read_buf16 : nand_read_buf;
3069 	if (!chip->scan_bbt)
3070 		chip->scan_bbt = nand_default_bbt;
3071 
3072 	if (!chip->controller) {
3073 		chip->controller = &chip->hwcontrol;
3074 		spin_lock_init(&chip->controller->lock);
3075 		init_waitqueue_head(&chip->controller->wq);
3076 	}
3077 
3078 	if (!chip->buf_align)
3079 		chip->buf_align = 1;
3080 }
3081 
3082 /* Sanitize ONFI strings so we can safely print them */
3083 static void sanitize_string(char *s, size_t len)
3084 {
3085 	ssize_t i;
3086 
3087 	/* Null terminate */
3088 	s[len - 1] = 0;
3089 
3090 	/* Remove non printable chars */
3091 	for (i = 0; i < len - 1; i++) {
3092 		if (s[i] < ' ' || s[i] > 127)
3093 			s[i] = '?';
3094 	}
3095 
3096 	/* Remove trailing spaces */
3097 	strim(s);
3098 }
3099 
3100 static u16 onfi_crc16(u16 crc, u8 const *p, size_t len)
3101 {
3102 	int i;
3103 	while (len--) {
3104 		crc ^= *p++ << 8;
3105 		for (i = 0; i < 8; i++)
3106 			crc = (crc << 1) ^ ((crc & 0x8000) ? 0x8005 : 0);
3107 	}
3108 
3109 	return crc;
3110 }
3111 
3112 #ifdef CONFIG_SYS_NAND_ONFI_DETECTION
3113 /* Parse the Extended Parameter Page. */
3114 static int nand_flash_detect_ext_param_page(struct mtd_info *mtd,
3115 		struct nand_chip *chip, struct nand_onfi_params *p)
3116 {
3117 	struct onfi_ext_param_page *ep;
3118 	struct onfi_ext_section *s;
3119 	struct onfi_ext_ecc_info *ecc;
3120 	uint8_t *cursor;
3121 	int ret = -EINVAL;
3122 	int len;
3123 	int i;
3124 
3125 	len = le16_to_cpu(p->ext_param_page_length) * 16;
3126 	ep = kmalloc(len, GFP_KERNEL);
3127 	if (!ep)
3128 		return -ENOMEM;
3129 
3130 	/* Send our own NAND_CMD_PARAM. */
3131 	chip->cmdfunc(mtd, NAND_CMD_PARAM, 0, -1);
3132 
3133 	/* Use the Change Read Column command to skip the ONFI param pages. */
3134 	chip->cmdfunc(mtd, NAND_CMD_RNDOUT,
3135 			sizeof(*p) * p->num_of_param_pages , -1);
3136 
3137 	/* Read out the Extended Parameter Page. */
3138 	chip->read_buf(mtd, (uint8_t *)ep, len);
3139 	if ((onfi_crc16(ONFI_CRC_BASE, ((uint8_t *)ep) + 2, len - 2)
3140 		!= le16_to_cpu(ep->crc))) {
3141 		pr_debug("fail in the CRC.\n");
3142 		goto ext_out;
3143 	}
3144 
3145 	/*
3146 	 * Check the signature.
3147 	 * Do not strictly follow the ONFI spec, maybe changed in future.
3148 	 */
3149 	if (strncmp((char *)ep->sig, "EPPS", 4)) {
3150 		pr_debug("The signature is invalid.\n");
3151 		goto ext_out;
3152 	}
3153 
3154 	/* find the ECC section. */
3155 	cursor = (uint8_t *)(ep + 1);
3156 	for (i = 0; i < ONFI_EXT_SECTION_MAX; i++) {
3157 		s = ep->sections + i;
3158 		if (s->type == ONFI_SECTION_TYPE_2)
3159 			break;
3160 		cursor += s->length * 16;
3161 	}
3162 	if (i == ONFI_EXT_SECTION_MAX) {
3163 		pr_debug("We can not find the ECC section.\n");
3164 		goto ext_out;
3165 	}
3166 
3167 	/* get the info we want. */
3168 	ecc = (struct onfi_ext_ecc_info *)cursor;
3169 
3170 	if (!ecc->codeword_size) {
3171 		pr_debug("Invalid codeword size\n");
3172 		goto ext_out;
3173 	}
3174 
3175 	chip->ecc_strength_ds = ecc->ecc_bits;
3176 	chip->ecc_step_ds = 1 << ecc->codeword_size;
3177 	ret = 0;
3178 
3179 ext_out:
3180 	kfree(ep);
3181 	return ret;
3182 }
3183 
3184 static int nand_setup_read_retry_micron(struct mtd_info *mtd, int retry_mode)
3185 {
3186 	struct nand_chip *chip = mtd_to_nand(mtd);
3187 	uint8_t feature[ONFI_SUBFEATURE_PARAM_LEN] = {retry_mode};
3188 
3189 	return chip->onfi_set_features(mtd, chip, ONFI_FEATURE_ADDR_READ_RETRY,
3190 			feature);
3191 }
3192 
3193 /*
3194  * Configure chip properties from Micron vendor-specific ONFI table
3195  */
3196 static void nand_onfi_detect_micron(struct nand_chip *chip,
3197 		struct nand_onfi_params *p)
3198 {
3199 	struct nand_onfi_vendor_micron *micron = (void *)p->vendor;
3200 
3201 	if (le16_to_cpu(p->vendor_revision) < 1)
3202 		return;
3203 
3204 	chip->read_retries = micron->read_retry_options;
3205 	chip->setup_read_retry = nand_setup_read_retry_micron;
3206 }
3207 
3208 /*
3209  * Check if the NAND chip is ONFI compliant, returns 1 if it is, 0 otherwise.
3210  */
3211 static int nand_flash_detect_onfi(struct mtd_info *mtd, struct nand_chip *chip,
3212 					int *busw)
3213 {
3214 	struct nand_onfi_params *p = &chip->onfi_params;
3215 	int i, j;
3216 	int val;
3217 
3218 	/* Try ONFI for unknown chip or LP */
3219 	chip->cmdfunc(mtd, NAND_CMD_READID, 0x20, -1);
3220 	if (chip->read_byte(mtd) != 'O' || chip->read_byte(mtd) != 'N' ||
3221 		chip->read_byte(mtd) != 'F' || chip->read_byte(mtd) != 'I')
3222 		return 0;
3223 
3224 	chip->cmdfunc(mtd, NAND_CMD_PARAM, 0, -1);
3225 	for (i = 0; i < 3; i++) {
3226 		for (j = 0; j < sizeof(*p); j++)
3227 			((uint8_t *)p)[j] = chip->read_byte(mtd);
3228 		if (onfi_crc16(ONFI_CRC_BASE, (uint8_t *)p, 254) ==
3229 				le16_to_cpu(p->crc)) {
3230 			break;
3231 		}
3232 	}
3233 
3234 	if (i == 3) {
3235 		pr_err("Could not find valid ONFI parameter page; aborting\n");
3236 		return 0;
3237 	}
3238 
3239 	/* Check version */
3240 	val = le16_to_cpu(p->revision);
3241 	if (val & (1 << 5))
3242 		chip->onfi_version = 23;
3243 	else if (val & (1 << 4))
3244 		chip->onfi_version = 22;
3245 	else if (val & (1 << 3))
3246 		chip->onfi_version = 21;
3247 	else if (val & (1 << 2))
3248 		chip->onfi_version = 20;
3249 	else if (val & (1 << 1))
3250 		chip->onfi_version = 10;
3251 
3252 	if (!chip->onfi_version) {
3253 		pr_info("unsupported ONFI version: %d\n", val);
3254 		return 0;
3255 	}
3256 
3257 	sanitize_string(p->manufacturer, sizeof(p->manufacturer));
3258 	sanitize_string(p->model, sizeof(p->model));
3259 	if (!mtd->name)
3260 		mtd->name = p->model;
3261 
3262 	mtd->writesize = le32_to_cpu(p->byte_per_page);
3263 
3264 	/*
3265 	 * pages_per_block and blocks_per_lun may not be a power-of-2 size
3266 	 * (don't ask me who thought of this...). MTD assumes that these
3267 	 * dimensions will be power-of-2, so just truncate the remaining area.
3268 	 */
3269 	mtd->erasesize = 1 << (fls(le32_to_cpu(p->pages_per_block)) - 1);
3270 	mtd->erasesize *= mtd->writesize;
3271 
3272 	mtd->oobsize = le16_to_cpu(p->spare_bytes_per_page);
3273 
3274 	/* See erasesize comment */
3275 	chip->chipsize = 1 << (fls(le32_to_cpu(p->blocks_per_lun)) - 1);
3276 	chip->chipsize *= (uint64_t)mtd->erasesize * p->lun_count;
3277 	chip->bits_per_cell = p->bits_per_cell;
3278 
3279 	if (onfi_feature(chip) & ONFI_FEATURE_16_BIT_BUS)
3280 		*busw = NAND_BUSWIDTH_16;
3281 	else
3282 		*busw = 0;
3283 
3284 	if (p->ecc_bits != 0xff) {
3285 		chip->ecc_strength_ds = p->ecc_bits;
3286 		chip->ecc_step_ds = 512;
3287 	} else if (chip->onfi_version >= 21 &&
3288 		(onfi_feature(chip) & ONFI_FEATURE_EXT_PARAM_PAGE)) {
3289 
3290 		/*
3291 		 * The nand_flash_detect_ext_param_page() uses the
3292 		 * Change Read Column command which maybe not supported
3293 		 * by the chip->cmdfunc. So try to update the chip->cmdfunc
3294 		 * now. We do not replace user supplied command function.
3295 		 */
3296 		if (mtd->writesize > 512 && chip->cmdfunc == nand_command)
3297 			chip->cmdfunc = nand_command_lp;
3298 
3299 		/* The Extended Parameter Page is supported since ONFI 2.1. */
3300 		if (nand_flash_detect_ext_param_page(mtd, chip, p))
3301 			pr_warn("Failed to detect ONFI extended param page\n");
3302 	} else {
3303 		pr_warn("Could not retrieve ONFI ECC requirements\n");
3304 	}
3305 
3306 	if (p->jedec_id == NAND_MFR_MICRON)
3307 		nand_onfi_detect_micron(chip, p);
3308 
3309 	return 1;
3310 }
3311 #else
3312 static int nand_flash_detect_onfi(struct mtd_info *mtd, struct nand_chip *chip,
3313 					int *busw)
3314 {
3315 	return 0;
3316 }
3317 #endif
3318 
3319 /*
3320  * Check if the NAND chip is JEDEC compliant, returns 1 if it is, 0 otherwise.
3321  */
3322 static int nand_flash_detect_jedec(struct mtd_info *mtd, struct nand_chip *chip,
3323 					int *busw)
3324 {
3325 	struct nand_jedec_params *p = &chip->jedec_params;
3326 	struct jedec_ecc_info *ecc;
3327 	int val;
3328 	int i, j;
3329 
3330 	/* Try JEDEC for unknown chip or LP */
3331 	chip->cmdfunc(mtd, NAND_CMD_READID, 0x40, -1);
3332 	if (chip->read_byte(mtd) != 'J' || chip->read_byte(mtd) != 'E' ||
3333 		chip->read_byte(mtd) != 'D' || chip->read_byte(mtd) != 'E' ||
3334 		chip->read_byte(mtd) != 'C')
3335 		return 0;
3336 
3337 	chip->cmdfunc(mtd, NAND_CMD_PARAM, 0x40, -1);
3338 	for (i = 0; i < 3; i++) {
3339 		for (j = 0; j < sizeof(*p); j++)
3340 			((uint8_t *)p)[j] = chip->read_byte(mtd);
3341 
3342 		if (onfi_crc16(ONFI_CRC_BASE, (uint8_t *)p, 510) ==
3343 				le16_to_cpu(p->crc))
3344 			break;
3345 	}
3346 
3347 	if (i == 3) {
3348 		pr_err("Could not find valid JEDEC parameter page; aborting\n");
3349 		return 0;
3350 	}
3351 
3352 	/* Check version */
3353 	val = le16_to_cpu(p->revision);
3354 	if (val & (1 << 2))
3355 		chip->jedec_version = 10;
3356 	else if (val & (1 << 1))
3357 		chip->jedec_version = 1; /* vendor specific version */
3358 
3359 	if (!chip->jedec_version) {
3360 		pr_info("unsupported JEDEC version: %d\n", val);
3361 		return 0;
3362 	}
3363 
3364 	sanitize_string(p->manufacturer, sizeof(p->manufacturer));
3365 	sanitize_string(p->model, sizeof(p->model));
3366 	if (!mtd->name)
3367 		mtd->name = p->model;
3368 
3369 	mtd->writesize = le32_to_cpu(p->byte_per_page);
3370 
3371 	/* Please reference to the comment for nand_flash_detect_onfi. */
3372 	mtd->erasesize = 1 << (fls(le32_to_cpu(p->pages_per_block)) - 1);
3373 	mtd->erasesize *= mtd->writesize;
3374 
3375 	mtd->oobsize = le16_to_cpu(p->spare_bytes_per_page);
3376 
3377 	/* Please reference to the comment for nand_flash_detect_onfi. */
3378 	chip->chipsize = 1 << (fls(le32_to_cpu(p->blocks_per_lun)) - 1);
3379 	chip->chipsize *= (uint64_t)mtd->erasesize * p->lun_count;
3380 	chip->bits_per_cell = p->bits_per_cell;
3381 
3382 	if (jedec_feature(chip) & JEDEC_FEATURE_16_BIT_BUS)
3383 		*busw = NAND_BUSWIDTH_16;
3384 	else
3385 		*busw = 0;
3386 
3387 	/* ECC info */
3388 	ecc = &p->ecc_info[0];
3389 
3390 	if (ecc->codeword_size >= 9) {
3391 		chip->ecc_strength_ds = ecc->ecc_bits;
3392 		chip->ecc_step_ds = 1 << ecc->codeword_size;
3393 	} else {
3394 		pr_warn("Invalid codeword size\n");
3395 	}
3396 
3397 	return 1;
3398 }
3399 
3400 /*
3401  * nand_id_has_period - Check if an ID string has a given wraparound period
3402  * @id_data: the ID string
3403  * @arrlen: the length of the @id_data array
3404  * @period: the period of repitition
3405  *
3406  * Check if an ID string is repeated within a given sequence of bytes at
3407  * specific repetition interval period (e.g., {0x20,0x01,0x7F,0x20} has a
3408  * period of 3). This is a helper function for nand_id_len(). Returns non-zero
3409  * if the repetition has a period of @period; otherwise, returns zero.
3410  */
3411 static int nand_id_has_period(u8 *id_data, int arrlen, int period)
3412 {
3413 	int i, j;
3414 	for (i = 0; i < period; i++)
3415 		for (j = i + period; j < arrlen; j += period)
3416 			if (id_data[i] != id_data[j])
3417 				return 0;
3418 	return 1;
3419 }
3420 
3421 /*
3422  * nand_id_len - Get the length of an ID string returned by CMD_READID
3423  * @id_data: the ID string
3424  * @arrlen: the length of the @id_data array
3425 
3426  * Returns the length of the ID string, according to known wraparound/trailing
3427  * zero patterns. If no pattern exists, returns the length of the array.
3428  */
3429 static int nand_id_len(u8 *id_data, int arrlen)
3430 {
3431 	int last_nonzero, period;
3432 
3433 	/* Find last non-zero byte */
3434 	for (last_nonzero = arrlen - 1; last_nonzero >= 0; last_nonzero--)
3435 		if (id_data[last_nonzero])
3436 			break;
3437 
3438 	/* All zeros */
3439 	if (last_nonzero < 0)
3440 		return 0;
3441 
3442 	/* Calculate wraparound period */
3443 	for (period = 1; period < arrlen; period++)
3444 		if (nand_id_has_period(id_data, arrlen, period))
3445 			break;
3446 
3447 	/* There's a repeated pattern */
3448 	if (period < arrlen)
3449 		return period;
3450 
3451 	/* There are trailing zeros */
3452 	if (last_nonzero < arrlen - 1)
3453 		return last_nonzero + 1;
3454 
3455 	/* No pattern detected */
3456 	return arrlen;
3457 }
3458 
3459 /* Extract the bits of per cell from the 3rd byte of the extended ID */
3460 static int nand_get_bits_per_cell(u8 cellinfo)
3461 {
3462 	int bits;
3463 
3464 	bits = cellinfo & NAND_CI_CELLTYPE_MSK;
3465 	bits >>= NAND_CI_CELLTYPE_SHIFT;
3466 	return bits + 1;
3467 }
3468 
3469 /*
3470  * Many new NAND share similar device ID codes, which represent the size of the
3471  * chip. The rest of the parameters must be decoded according to generic or
3472  * manufacturer-specific "extended ID" decoding patterns.
3473  */
3474 static void nand_decode_ext_id(struct mtd_info *mtd, struct nand_chip *chip,
3475 				u8 id_data[8], int *busw)
3476 {
3477 	int extid, id_len;
3478 	/* The 3rd id byte holds MLC / multichip data */
3479 	chip->bits_per_cell = nand_get_bits_per_cell(id_data[2]);
3480 	/* The 4th id byte is the important one */
3481 	extid = id_data[3];
3482 
3483 	id_len = nand_id_len(id_data, 8);
3484 
3485 	/*
3486 	 * Field definitions are in the following datasheets:
3487 	 * Old style (4,5 byte ID): Samsung K9GAG08U0M (p.32)
3488 	 * New Samsung (6 byte ID): Samsung K9GAG08U0F (p.44)
3489 	 * Hynix MLC   (6 byte ID): Hynix H27UBG8T2B (p.22)
3490 	 *
3491 	 * Check for ID length, non-zero 6th byte, cell type, and Hynix/Samsung
3492 	 * ID to decide what to do.
3493 	 */
3494 	if (id_len == 6 && id_data[0] == NAND_MFR_SAMSUNG &&
3495 			!nand_is_slc(chip) && id_data[5] != 0x00) {
3496 		/* Calc pagesize */
3497 		mtd->writesize = 2048 << (extid & 0x03);
3498 		extid >>= 2;
3499 		/* Calc oobsize */
3500 		switch (((extid >> 2) & 0x04) | (extid & 0x03)) {
3501 		case 1:
3502 			mtd->oobsize = 128;
3503 			break;
3504 		case 2:
3505 			mtd->oobsize = 218;
3506 			break;
3507 		case 3:
3508 			mtd->oobsize = 400;
3509 			break;
3510 		case 4:
3511 			mtd->oobsize = 436;
3512 			break;
3513 		case 5:
3514 			mtd->oobsize = 512;
3515 			break;
3516 		case 6:
3517 			mtd->oobsize = 640;
3518 			break;
3519 		case 7:
3520 		default: /* Other cases are "reserved" (unknown) */
3521 			mtd->oobsize = 1024;
3522 			break;
3523 		}
3524 		extid >>= 2;
3525 		/* Calc blocksize */
3526 		mtd->erasesize = (128 * 1024) <<
3527 			(((extid >> 1) & 0x04) | (extid & 0x03));
3528 		*busw = 0;
3529 	} else if (id_len == 6 && id_data[0] == NAND_MFR_HYNIX &&
3530 			!nand_is_slc(chip)) {
3531 		unsigned int tmp;
3532 
3533 		/* Calc pagesize */
3534 		mtd->writesize = 2048 << (extid & 0x03);
3535 		extid >>= 2;
3536 		/* Calc oobsize */
3537 		switch (((extid >> 2) & 0x04) | (extid & 0x03)) {
3538 		case 0:
3539 			mtd->oobsize = 128;
3540 			break;
3541 		case 1:
3542 			mtd->oobsize = 224;
3543 			break;
3544 		case 2:
3545 			mtd->oobsize = 448;
3546 			break;
3547 		case 3:
3548 			mtd->oobsize = 64;
3549 			break;
3550 		case 4:
3551 			mtd->oobsize = 32;
3552 			break;
3553 		case 5:
3554 			mtd->oobsize = 16;
3555 			break;
3556 		default:
3557 			mtd->oobsize = 640;
3558 			break;
3559 		}
3560 		extid >>= 2;
3561 		/* Calc blocksize */
3562 		tmp = ((extid >> 1) & 0x04) | (extid & 0x03);
3563 		if (tmp < 0x03)
3564 			mtd->erasesize = (128 * 1024) << tmp;
3565 		else if (tmp == 0x03)
3566 			mtd->erasesize = 768 * 1024;
3567 		else
3568 			mtd->erasesize = (64 * 1024) << tmp;
3569 		*busw = 0;
3570 	} else {
3571 		/* Calc pagesize */
3572 		mtd->writesize = 1024 << (extid & 0x03);
3573 		extid >>= 2;
3574 		/* Calc oobsize */
3575 		mtd->oobsize = (8 << (extid & 0x01)) *
3576 			(mtd->writesize >> 9);
3577 		extid >>= 2;
3578 		/* Calc blocksize. Blocksize is multiples of 64KiB */
3579 		mtd->erasesize = (64 * 1024) << (extid & 0x03);
3580 		extid >>= 2;
3581 		/* Get buswidth information */
3582 		*busw = (extid & 0x01) ? NAND_BUSWIDTH_16 : 0;
3583 
3584 		/*
3585 		 * Toshiba 24nm raw SLC (i.e., not BENAND) have 32B OOB per
3586 		 * 512B page. For Toshiba SLC, we decode the 5th/6th byte as
3587 		 * follows:
3588 		 * - ID byte 6, bits[2:0]: 100b -> 43nm, 101b -> 32nm,
3589 		 *                         110b -> 24nm
3590 		 * - ID byte 5, bit[7]:    1 -> BENAND, 0 -> raw SLC
3591 		 */
3592 		if (id_len >= 6 && id_data[0] == NAND_MFR_TOSHIBA &&
3593 				nand_is_slc(chip) &&
3594 				(id_data[5] & 0x7) == 0x6 /* 24nm */ &&
3595 				!(id_data[4] & 0x80) /* !BENAND */) {
3596 			mtd->oobsize = 32 * mtd->writesize >> 9;
3597 		}
3598 
3599 	}
3600 }
3601 
3602 /*
3603  * Old devices have chip data hardcoded in the device ID table. nand_decode_id
3604  * decodes a matching ID table entry and assigns the MTD size parameters for
3605  * the chip.
3606  */
3607 static void nand_decode_id(struct mtd_info *mtd, struct nand_chip *chip,
3608 				struct nand_flash_dev *type, u8 id_data[8],
3609 				int *busw)
3610 {
3611 	int maf_id = id_data[0];
3612 
3613 	mtd->erasesize = type->erasesize;
3614 	mtd->writesize = type->pagesize;
3615 	mtd->oobsize = mtd->writesize / 32;
3616 	*busw = type->options & NAND_BUSWIDTH_16;
3617 
3618 	/* All legacy ID NAND are small-page, SLC */
3619 	chip->bits_per_cell = 1;
3620 
3621 	/*
3622 	 * Check for Spansion/AMD ID + repeating 5th, 6th byte since
3623 	 * some Spansion chips have erasesize that conflicts with size
3624 	 * listed in nand_ids table.
3625 	 * Data sheet (5 byte ID): Spansion S30ML-P ORNAND (p.39)
3626 	 */
3627 	if (maf_id == NAND_MFR_AMD && id_data[4] != 0x00 && id_data[5] == 0x00
3628 			&& id_data[6] == 0x00 && id_data[7] == 0x00
3629 			&& mtd->writesize == 512) {
3630 		mtd->erasesize = 128 * 1024;
3631 		mtd->erasesize <<= ((id_data[3] & 0x03) << 1);
3632 	}
3633 }
3634 
3635 /*
3636  * Set the bad block marker/indicator (BBM/BBI) patterns according to some
3637  * heuristic patterns using various detected parameters (e.g., manufacturer,
3638  * page size, cell-type information).
3639  */
3640 static void nand_decode_bbm_options(struct mtd_info *mtd,
3641 				    struct nand_chip *chip, u8 id_data[8])
3642 {
3643 	int maf_id = id_data[0];
3644 
3645 	/* Set the bad block position */
3646 	if (mtd->writesize > 512 || (chip->options & NAND_BUSWIDTH_16))
3647 		chip->badblockpos = NAND_LARGE_BADBLOCK_POS;
3648 	else
3649 		chip->badblockpos = NAND_SMALL_BADBLOCK_POS;
3650 
3651 	/*
3652 	 * Bad block marker is stored in the last page of each block on Samsung
3653 	 * and Hynix MLC devices; stored in first two pages of each block on
3654 	 * Micron devices with 2KiB pages and on SLC Samsung, Hynix, Toshiba,
3655 	 * AMD/Spansion, and Macronix.  All others scan only the first page.
3656 	 */
3657 	if (!nand_is_slc(chip) &&
3658 			(maf_id == NAND_MFR_SAMSUNG ||
3659 			 maf_id == NAND_MFR_HYNIX))
3660 		chip->bbt_options |= NAND_BBT_SCANLASTPAGE;
3661 	else if ((nand_is_slc(chip) &&
3662 				(maf_id == NAND_MFR_SAMSUNG ||
3663 				 maf_id == NAND_MFR_HYNIX ||
3664 				 maf_id == NAND_MFR_TOSHIBA ||
3665 				 maf_id == NAND_MFR_AMD ||
3666 				 maf_id == NAND_MFR_MACRONIX)) ||
3667 			(mtd->writesize == 2048 &&
3668 			 maf_id == NAND_MFR_MICRON))
3669 		chip->bbt_options |= NAND_BBT_SCAN2NDPAGE;
3670 }
3671 
3672 static inline bool is_full_id_nand(struct nand_flash_dev *type)
3673 {
3674 	return type->id_len;
3675 }
3676 
3677 static bool find_full_id_nand(struct mtd_info *mtd, struct nand_chip *chip,
3678 		   struct nand_flash_dev *type, u8 *id_data, int *busw)
3679 {
3680 	if (!strncmp((char *)type->id, (char *)id_data, type->id_len)) {
3681 		mtd->writesize = type->pagesize;
3682 		mtd->erasesize = type->erasesize;
3683 		mtd->oobsize = type->oobsize;
3684 
3685 		chip->bits_per_cell = nand_get_bits_per_cell(id_data[2]);
3686 		chip->chipsize = (uint64_t)type->chipsize << 20;
3687 		chip->options |= type->options;
3688 		chip->ecc_strength_ds = NAND_ECC_STRENGTH(type);
3689 		chip->ecc_step_ds = NAND_ECC_STEP(type);
3690 		chip->onfi_timing_mode_default =
3691 					type->onfi_timing_mode_default;
3692 
3693 		*busw = type->options & NAND_BUSWIDTH_16;
3694 
3695 		if (!mtd->name)
3696 			mtd->name = type->name;
3697 
3698 		return true;
3699 	}
3700 	return false;
3701 }
3702 
3703 /*
3704  * Get the flash and manufacturer id and lookup if the type is supported.
3705  */
3706 struct nand_flash_dev *nand_get_flash_type(struct mtd_info *mtd,
3707 						  struct nand_chip *chip,
3708 						  int *maf_id, int *dev_id,
3709 						  struct nand_flash_dev *type)
3710 {
3711 	int busw;
3712 	int i, maf_idx;
3713 	u8 id_data[8];
3714 
3715 	/*
3716 	 * Reset the chip, required by some chips (e.g. Micron MT29FxGxxxxx)
3717 	 * after power-up.
3718 	 */
3719 	nand_reset(chip, 0);
3720 
3721 	/* Select the device */
3722 	chip->select_chip(mtd, 0);
3723 
3724 	/* Send the command for reading device ID */
3725 	chip->cmdfunc(mtd, NAND_CMD_READID, 0x00, -1);
3726 
3727 	/* Read manufacturer and device IDs */
3728 	*maf_id = chip->read_byte(mtd);
3729 	*dev_id = chip->read_byte(mtd);
3730 
3731 	/*
3732 	 * Try again to make sure, as some systems the bus-hold or other
3733 	 * interface concerns can cause random data which looks like a
3734 	 * possibly credible NAND flash to appear. If the two results do
3735 	 * not match, ignore the device completely.
3736 	 */
3737 
3738 	chip->cmdfunc(mtd, NAND_CMD_READID, 0x00, -1);
3739 
3740 	/* Read entire ID string */
3741 	for (i = 0; i < 8; i++)
3742 		id_data[i] = chip->read_byte(mtd);
3743 
3744 	if (id_data[0] != *maf_id || id_data[1] != *dev_id) {
3745 		pr_info("second ID read did not match %02x,%02x against %02x,%02x\n",
3746 			*maf_id, *dev_id, id_data[0], id_data[1]);
3747 		return ERR_PTR(-ENODEV);
3748 	}
3749 
3750 	if (!type)
3751 		type = nand_flash_ids;
3752 
3753 	for (; type->name != NULL; type++) {
3754 		if (is_full_id_nand(type)) {
3755 			if (find_full_id_nand(mtd, chip, type, id_data, &busw))
3756 				goto ident_done;
3757 		} else if (*dev_id == type->dev_id) {
3758 			break;
3759 		}
3760 	}
3761 
3762 	chip->onfi_version = 0;
3763 	if (!type->name || !type->pagesize) {
3764 		/* Check if the chip is ONFI compliant */
3765 		if (nand_flash_detect_onfi(mtd, chip, &busw))
3766 			goto ident_done;
3767 
3768 		/* Check if the chip is JEDEC compliant */
3769 		if (nand_flash_detect_jedec(mtd, chip, &busw))
3770 			goto ident_done;
3771 	}
3772 
3773 	if (!type->name)
3774 		return ERR_PTR(-ENODEV);
3775 
3776 	if (!mtd->name)
3777 		mtd->name = type->name;
3778 
3779 	chip->chipsize = (uint64_t)type->chipsize << 20;
3780 
3781 	if (!type->pagesize) {
3782 		/* Decode parameters from extended ID */
3783 		nand_decode_ext_id(mtd, chip, id_data, &busw);
3784 	} else {
3785 		nand_decode_id(mtd, chip, type, id_data, &busw);
3786 	}
3787 	/* Get chip options */
3788 	chip->options |= type->options;
3789 
3790 	/*
3791 	 * Check if chip is not a Samsung device. Do not clear the
3792 	 * options for chips which do not have an extended id.
3793 	 */
3794 	if (*maf_id != NAND_MFR_SAMSUNG && !type->pagesize)
3795 		chip->options &= ~NAND_SAMSUNG_LP_OPTIONS;
3796 ident_done:
3797 
3798 	/* Try to identify manufacturer */
3799 	for (maf_idx = 0; nand_manuf_ids[maf_idx].id != 0x0; maf_idx++) {
3800 		if (nand_manuf_ids[maf_idx].id == *maf_id)
3801 			break;
3802 	}
3803 
3804 	if (chip->options & NAND_BUSWIDTH_AUTO) {
3805 		WARN_ON(chip->options & NAND_BUSWIDTH_16);
3806 		chip->options |= busw;
3807 		nand_set_defaults(chip, busw);
3808 	} else if (busw != (chip->options & NAND_BUSWIDTH_16)) {
3809 		/*
3810 		 * Check, if buswidth is correct. Hardware drivers should set
3811 		 * chip correct!
3812 		 */
3813 		pr_info("device found, Manufacturer ID: 0x%02x, Chip ID: 0x%02x\n",
3814 			*maf_id, *dev_id);
3815 		pr_info("%s %s\n", nand_manuf_ids[maf_idx].name, mtd->name);
3816 		pr_warn("bus width %d instead %d bit\n",
3817 			   (chip->options & NAND_BUSWIDTH_16) ? 16 : 8,
3818 			   busw ? 16 : 8);
3819 		return ERR_PTR(-EINVAL);
3820 	}
3821 
3822 	nand_decode_bbm_options(mtd, chip, id_data);
3823 
3824 	/* Calculate the address shift from the page size */
3825 	chip->page_shift = ffs(mtd->writesize) - 1;
3826 	/* Convert chipsize to number of pages per chip -1 */
3827 	chip->pagemask = (chip->chipsize >> chip->page_shift) - 1;
3828 
3829 	chip->bbt_erase_shift = chip->phys_erase_shift =
3830 		ffs(mtd->erasesize) - 1;
3831 	if (chip->chipsize & 0xffffffff)
3832 		chip->chip_shift = ffs((unsigned)chip->chipsize) - 1;
3833 	else {
3834 		chip->chip_shift = ffs((unsigned)(chip->chipsize >> 32));
3835 		chip->chip_shift += 32 - 1;
3836 	}
3837 
3838 	if (chip->chip_shift - chip->page_shift > 16)
3839 		chip->options |= NAND_ROW_ADDR_3;
3840 
3841 	chip->badblockbits = 8;
3842 	chip->erase = single_erase;
3843 
3844 	/* Do not replace user supplied command function! */
3845 	if (mtd->writesize > 512 && chip->cmdfunc == nand_command)
3846 		chip->cmdfunc = nand_command_lp;
3847 
3848 	pr_info("device found, Manufacturer ID: 0x%02x, Chip ID: 0x%02x\n",
3849 		*maf_id, *dev_id);
3850 
3851 #ifdef CONFIG_SYS_NAND_ONFI_DETECTION
3852 	if (chip->onfi_version)
3853 		pr_info("%s %s\n", nand_manuf_ids[maf_idx].name,
3854 				chip->onfi_params.model);
3855 	else if (chip->jedec_version)
3856 		pr_info("%s %s\n", nand_manuf_ids[maf_idx].name,
3857 				chip->jedec_params.model);
3858 	else
3859 		pr_info("%s %s\n", nand_manuf_ids[maf_idx].name,
3860 				type->name);
3861 #else
3862 	if (chip->jedec_version)
3863 		pr_info("%s %s\n", nand_manuf_ids[maf_idx].name,
3864 				chip->jedec_params.model);
3865 	else
3866 		pr_info("%s %s\n", nand_manuf_ids[maf_idx].name,
3867 				type->name);
3868 
3869 	pr_info("%s %s\n", nand_manuf_ids[maf_idx].name,
3870 		type->name);
3871 #endif
3872 
3873 	pr_info("%d MiB, %s, erase size: %d KiB, page size: %d, OOB size: %d\n",
3874 		(int)(chip->chipsize >> 20), nand_is_slc(chip) ? "SLC" : "MLC",
3875 		mtd->erasesize >> 10, mtd->writesize, mtd->oobsize);
3876 	return type;
3877 }
3878 EXPORT_SYMBOL(nand_get_flash_type);
3879 
3880 #if CONFIG_IS_ENABLED(OF_CONTROL)
3881 DECLARE_GLOBAL_DATA_PTR;
3882 
3883 static int nand_dt_init(struct mtd_info *mtd, struct nand_chip *chip, int node)
3884 {
3885 	int ret, ecc_mode = -1, ecc_strength, ecc_step;
3886 	const void *blob = gd->fdt_blob;
3887 	const char *str;
3888 
3889 	ret = fdtdec_get_int(blob, node, "nand-bus-width", -1);
3890 	if (ret == 16)
3891 		chip->options |= NAND_BUSWIDTH_16;
3892 
3893 	if (fdtdec_get_bool(blob, node, "nand-on-flash-bbt"))
3894 		chip->bbt_options |= NAND_BBT_USE_FLASH;
3895 
3896 	str = fdt_getprop(blob, node, "nand-ecc-mode", NULL);
3897 	if (str) {
3898 		if (!strcmp(str, "none"))
3899 			ecc_mode = NAND_ECC_NONE;
3900 		else if (!strcmp(str, "soft"))
3901 			ecc_mode = NAND_ECC_SOFT;
3902 		else if (!strcmp(str, "hw"))
3903 			ecc_mode = NAND_ECC_HW;
3904 		else if (!strcmp(str, "hw_syndrome"))
3905 			ecc_mode = NAND_ECC_HW_SYNDROME;
3906 		else if (!strcmp(str, "hw_oob_first"))
3907 			ecc_mode = NAND_ECC_HW_OOB_FIRST;
3908 		else if (!strcmp(str, "soft_bch"))
3909 			ecc_mode = NAND_ECC_SOFT_BCH;
3910 	}
3911 
3912 
3913 	ecc_strength = fdtdec_get_int(blob, node, "nand-ecc-strength", -1);
3914 	ecc_step = fdtdec_get_int(blob, node, "nand-ecc-step-size", -1);
3915 
3916 	if ((ecc_step >= 0 && !(ecc_strength >= 0)) ||
3917 	    (!(ecc_step >= 0) && ecc_strength >= 0)) {
3918 		pr_err("must set both strength and step size in DT\n");
3919 		return -EINVAL;
3920 	}
3921 
3922 	if (ecc_mode >= 0)
3923 		chip->ecc.mode = ecc_mode;
3924 
3925 	if (ecc_strength >= 0)
3926 		chip->ecc.strength = ecc_strength;
3927 
3928 	if (ecc_step > 0)
3929 		chip->ecc.size = ecc_step;
3930 
3931 	if (fdt_getprop(blob, node, "nand-ecc-maximize", NULL))
3932 		chip->ecc.options |= NAND_ECC_MAXIMIZE;
3933 
3934 	return 0;
3935 }
3936 #else
3937 static int nand_dt_init(struct mtd_info *mtd, struct nand_chip *chip, int node)
3938 {
3939 	return 0;
3940 }
3941 #endif /* CONFIG_IS_ENABLED(OF_CONTROL) */
3942 
3943 /**
3944  * nand_scan_ident - [NAND Interface] Scan for the NAND device
3945  * @mtd: MTD device structure
3946  * @maxchips: number of chips to scan for
3947  * @table: alternative NAND ID table
3948  *
3949  * This is the first phase of the normal nand_scan() function. It reads the
3950  * flash ID and sets up MTD fields accordingly.
3951  *
3952  */
3953 int nand_scan_ident(struct mtd_info *mtd, int maxchips,
3954 		    struct nand_flash_dev *table)
3955 {
3956 	int i, nand_maf_id, nand_dev_id;
3957 	struct nand_chip *chip = mtd_to_nand(mtd);
3958 	struct nand_flash_dev *type;
3959 	int ret;
3960 
3961 	if (chip->flash_node) {
3962 		ret = nand_dt_init(mtd, chip, chip->flash_node);
3963 		if (ret)
3964 			return ret;
3965 	}
3966 
3967 	/* Set the default functions */
3968 	nand_set_defaults(chip, chip->options & NAND_BUSWIDTH_16);
3969 
3970 	/* Read the flash type */
3971 	type = nand_get_flash_type(mtd, chip, &nand_maf_id,
3972 				   &nand_dev_id, table);
3973 
3974 	if (IS_ERR(type)) {
3975 		if (!(chip->options & NAND_SCAN_SILENT_NODEV))
3976 			pr_warn("No NAND device found\n");
3977 		chip->select_chip(mtd, -1);
3978 		return PTR_ERR(type);
3979 	}
3980 
3981 	/* Initialize the ->data_interface field. */
3982 	ret = nand_init_data_interface(chip);
3983 	if (ret)
3984 		return ret;
3985 
3986 	/*
3987 	 * Setup the data interface correctly on the chip and controller side.
3988 	 * This explicit call to nand_setup_data_interface() is only required
3989 	 * for the first die, because nand_reset() has been called before
3990 	 * ->data_interface and ->default_onfi_timing_mode were set.
3991 	 * For the other dies, nand_reset() will automatically switch to the
3992 	 * best mode for us.
3993 	 */
3994 	ret = nand_setup_data_interface(chip, 0);
3995 	if (ret)
3996 		return ret;
3997 
3998 	chip->select_chip(mtd, -1);
3999 
4000 	/* Check for a chip array */
4001 	for (i = 1; i < maxchips; i++) {
4002 		/* See comment in nand_get_flash_type for reset */
4003 		nand_reset(chip, i);
4004 
4005 		chip->select_chip(mtd, i);
4006 		/* Send the command for reading device ID */
4007 		chip->cmdfunc(mtd, NAND_CMD_READID, 0x00, -1);
4008 		/* Read manufacturer and device IDs */
4009 		if (nand_maf_id != chip->read_byte(mtd) ||
4010 		    nand_dev_id != chip->read_byte(mtd)) {
4011 			chip->select_chip(mtd, -1);
4012 			break;
4013 		}
4014 		chip->select_chip(mtd, -1);
4015 	}
4016 
4017 #ifdef DEBUG
4018 	if (i > 1)
4019 		pr_info("%d chips detected\n", i);
4020 #endif
4021 
4022 	/* Store the number of chips and calc total size for mtd */
4023 	chip->numchips = i;
4024 	mtd->size = i * chip->chipsize;
4025 
4026 	return 0;
4027 }
4028 EXPORT_SYMBOL(nand_scan_ident);
4029 
4030 /**
4031  * nand_check_ecc_caps - check the sanity of preset ECC settings
4032  * @chip: nand chip info structure
4033  * @caps: ECC caps info structure
4034  * @oobavail: OOB size that the ECC engine can use
4035  *
4036  * When ECC step size and strength are already set, check if they are supported
4037  * by the controller and the calculated ECC bytes fit within the chip's OOB.
4038  * On success, the calculated ECC bytes is set.
4039  */
4040 int nand_check_ecc_caps(struct nand_chip *chip,
4041 			const struct nand_ecc_caps *caps, int oobavail)
4042 {
4043 	struct mtd_info *mtd = nand_to_mtd(chip);
4044 	const struct nand_ecc_step_info *stepinfo;
4045 	int preset_step = chip->ecc.size;
4046 	int preset_strength = chip->ecc.strength;
4047 	int nsteps, ecc_bytes;
4048 	int i, j;
4049 
4050 	if (WARN_ON(oobavail < 0))
4051 		return -EINVAL;
4052 
4053 	if (!preset_step || !preset_strength)
4054 		return -ENODATA;
4055 
4056 	nsteps = mtd->writesize / preset_step;
4057 
4058 	for (i = 0; i < caps->nstepinfos; i++) {
4059 		stepinfo = &caps->stepinfos[i];
4060 
4061 		if (stepinfo->stepsize != preset_step)
4062 			continue;
4063 
4064 		for (j = 0; j < stepinfo->nstrengths; j++) {
4065 			if (stepinfo->strengths[j] != preset_strength)
4066 				continue;
4067 
4068 			ecc_bytes = caps->calc_ecc_bytes(preset_step,
4069 							 preset_strength);
4070 			if (WARN_ON_ONCE(ecc_bytes < 0))
4071 				return ecc_bytes;
4072 
4073 			if (ecc_bytes * nsteps > oobavail) {
4074 				pr_err("ECC (step, strength) = (%d, %d) does not fit in OOB",
4075 				       preset_step, preset_strength);
4076 				return -ENOSPC;
4077 			}
4078 
4079 			chip->ecc.bytes = ecc_bytes;
4080 
4081 			return 0;
4082 		}
4083 	}
4084 
4085 	pr_err("ECC (step, strength) = (%d, %d) not supported on this controller",
4086 	       preset_step, preset_strength);
4087 
4088 	return -ENOTSUPP;
4089 }
4090 EXPORT_SYMBOL_GPL(nand_check_ecc_caps);
4091 
4092 /**
4093  * nand_match_ecc_req - meet the chip's requirement with least ECC bytes
4094  * @chip: nand chip info structure
4095  * @caps: ECC engine caps info structure
4096  * @oobavail: OOB size that the ECC engine can use
4097  *
4098  * If a chip's ECC requirement is provided, try to meet it with the least
4099  * number of ECC bytes (i.e. with the largest number of OOB-free bytes).
4100  * On success, the chosen ECC settings are set.
4101  */
4102 int nand_match_ecc_req(struct nand_chip *chip,
4103 		       const struct nand_ecc_caps *caps, int oobavail)
4104 {
4105 	struct mtd_info *mtd = nand_to_mtd(chip);
4106 	const struct nand_ecc_step_info *stepinfo;
4107 	int req_step = chip->ecc_step_ds;
4108 	int req_strength = chip->ecc_strength_ds;
4109 	int req_corr, step_size, strength, nsteps, ecc_bytes, ecc_bytes_total;
4110 	int best_step, best_strength, best_ecc_bytes;
4111 	int best_ecc_bytes_total = INT_MAX;
4112 	int i, j;
4113 
4114 	if (WARN_ON(oobavail < 0))
4115 		return -EINVAL;
4116 
4117 	/* No information provided by the NAND chip */
4118 	if (!req_step || !req_strength)
4119 		return -ENOTSUPP;
4120 
4121 	/* number of correctable bits the chip requires in a page */
4122 	req_corr = mtd->writesize / req_step * req_strength;
4123 
4124 	for (i = 0; i < caps->nstepinfos; i++) {
4125 		stepinfo = &caps->stepinfos[i];
4126 		step_size = stepinfo->stepsize;
4127 
4128 		for (j = 0; j < stepinfo->nstrengths; j++) {
4129 			strength = stepinfo->strengths[j];
4130 
4131 			/*
4132 			 * If both step size and strength are smaller than the
4133 			 * chip's requirement, it is not easy to compare the
4134 			 * resulted reliability.
4135 			 */
4136 			if (step_size < req_step && strength < req_strength)
4137 				continue;
4138 
4139 			if (mtd->writesize % step_size)
4140 				continue;
4141 
4142 			nsteps = mtd->writesize / step_size;
4143 
4144 			ecc_bytes = caps->calc_ecc_bytes(step_size, strength);
4145 			if (WARN_ON_ONCE(ecc_bytes < 0))
4146 				continue;
4147 			ecc_bytes_total = ecc_bytes * nsteps;
4148 
4149 			if (ecc_bytes_total > oobavail ||
4150 			    strength * nsteps < req_corr)
4151 				continue;
4152 
4153 			/*
4154 			 * We assume the best is to meet the chip's requrement
4155 			 * with the least number of ECC bytes.
4156 			 */
4157 			if (ecc_bytes_total < best_ecc_bytes_total) {
4158 				best_ecc_bytes_total = ecc_bytes_total;
4159 				best_step = step_size;
4160 				best_strength = strength;
4161 				best_ecc_bytes = ecc_bytes;
4162 			}
4163 		}
4164 	}
4165 
4166 	if (best_ecc_bytes_total == INT_MAX)
4167 		return -ENOTSUPP;
4168 
4169 	chip->ecc.size = best_step;
4170 	chip->ecc.strength = best_strength;
4171 	chip->ecc.bytes = best_ecc_bytes;
4172 
4173 	return 0;
4174 }
4175 EXPORT_SYMBOL_GPL(nand_match_ecc_req);
4176 
4177 /**
4178  * nand_maximize_ecc - choose the max ECC strength available
4179  * @chip: nand chip info structure
4180  * @caps: ECC engine caps info structure
4181  * @oobavail: OOB size that the ECC engine can use
4182  *
4183  * Choose the max ECC strength that is supported on the controller, and can fit
4184  * within the chip's OOB.  On success, the chosen ECC settings are set.
4185  */
4186 int nand_maximize_ecc(struct nand_chip *chip,
4187 		      const struct nand_ecc_caps *caps, int oobavail)
4188 {
4189 	struct mtd_info *mtd = nand_to_mtd(chip);
4190 	const struct nand_ecc_step_info *stepinfo;
4191 	int step_size, strength, nsteps, ecc_bytes, corr;
4192 	int best_corr = 0;
4193 	int best_step = 0;
4194 	int best_strength, best_ecc_bytes;
4195 	int i, j;
4196 
4197 	if (WARN_ON(oobavail < 0))
4198 		return -EINVAL;
4199 
4200 	for (i = 0; i < caps->nstepinfos; i++) {
4201 		stepinfo = &caps->stepinfos[i];
4202 		step_size = stepinfo->stepsize;
4203 
4204 		/* If chip->ecc.size is already set, respect it */
4205 		if (chip->ecc.size && step_size != chip->ecc.size)
4206 			continue;
4207 
4208 		for (j = 0; j < stepinfo->nstrengths; j++) {
4209 			strength = stepinfo->strengths[j];
4210 
4211 			if (mtd->writesize % step_size)
4212 				continue;
4213 
4214 			nsteps = mtd->writesize / step_size;
4215 
4216 			ecc_bytes = caps->calc_ecc_bytes(step_size, strength);
4217 			if (WARN_ON_ONCE(ecc_bytes < 0))
4218 				continue;
4219 
4220 			if (ecc_bytes * nsteps > oobavail)
4221 				continue;
4222 
4223 			corr = strength * nsteps;
4224 
4225 			/*
4226 			 * If the number of correctable bits is the same,
4227 			 * bigger step_size has more reliability.
4228 			 */
4229 			if (corr > best_corr ||
4230 			    (corr == best_corr && step_size > best_step)) {
4231 				best_corr = corr;
4232 				best_step = step_size;
4233 				best_strength = strength;
4234 				best_ecc_bytes = ecc_bytes;
4235 			}
4236 		}
4237 	}
4238 
4239 	if (!best_corr)
4240 		return -ENOTSUPP;
4241 
4242 	chip->ecc.size = best_step;
4243 	chip->ecc.strength = best_strength;
4244 	chip->ecc.bytes = best_ecc_bytes;
4245 
4246 	return 0;
4247 }
4248 EXPORT_SYMBOL_GPL(nand_maximize_ecc);
4249 
4250 /*
4251  * Check if the chip configuration meet the datasheet requirements.
4252 
4253  * If our configuration corrects A bits per B bytes and the minimum
4254  * required correction level is X bits per Y bytes, then we must ensure
4255  * both of the following are true:
4256  *
4257  * (1) A / B >= X / Y
4258  * (2) A >= X
4259  *
4260  * Requirement (1) ensures we can correct for the required bitflip density.
4261  * Requirement (2) ensures we can correct even when all bitflips are clumped
4262  * in the same sector.
4263  */
4264 static bool nand_ecc_strength_good(struct mtd_info *mtd)
4265 {
4266 	struct nand_chip *chip = mtd_to_nand(mtd);
4267 	struct nand_ecc_ctrl *ecc = &chip->ecc;
4268 	int corr, ds_corr;
4269 
4270 	if (ecc->size == 0 || chip->ecc_step_ds == 0)
4271 		/* Not enough information */
4272 		return true;
4273 
4274 	/*
4275 	 * We get the number of corrected bits per page to compare
4276 	 * the correction density.
4277 	 */
4278 	corr = (mtd->writesize * ecc->strength) / ecc->size;
4279 	ds_corr = (mtd->writesize * chip->ecc_strength_ds) / chip->ecc_step_ds;
4280 
4281 	return corr >= ds_corr && ecc->strength >= chip->ecc_strength_ds;
4282 }
4283 
4284 static bool invalid_ecc_page_accessors(struct nand_chip *chip)
4285 {
4286 	struct nand_ecc_ctrl *ecc = &chip->ecc;
4287 
4288 	if (nand_standard_page_accessors(ecc))
4289 		return false;
4290 
4291 	/*
4292 	 * NAND_ECC_CUSTOM_PAGE_ACCESS flag is set, make sure the NAND
4293 	 * controller driver implements all the page accessors because
4294 	 * default helpers are not suitable when the core does not
4295 	 * send the READ0/PAGEPROG commands.
4296 	 */
4297 	return (!ecc->read_page || !ecc->write_page ||
4298 		!ecc->read_page_raw || !ecc->write_page_raw ||
4299 		(NAND_HAS_SUBPAGE_READ(chip) && !ecc->read_subpage) ||
4300 		(NAND_HAS_SUBPAGE_WRITE(chip) && !ecc->write_subpage &&
4301 		 ecc->hwctl && ecc->calculate));
4302 }
4303 
4304 /**
4305  * nand_scan_tail - [NAND Interface] Scan for the NAND device
4306  * @mtd: MTD device structure
4307  *
4308  * This is the second phase of the normal nand_scan() function. It fills out
4309  * all the uninitialized function pointers with the defaults and scans for a
4310  * bad block table if appropriate.
4311  */
4312 int nand_scan_tail(struct mtd_info *mtd)
4313 {
4314 	int i;
4315 	struct nand_chip *chip = mtd_to_nand(mtd);
4316 	struct nand_ecc_ctrl *ecc = &chip->ecc;
4317 	struct nand_buffers *nbuf;
4318 
4319 	/* New bad blocks should be marked in OOB, flash-based BBT, or both */
4320 	BUG_ON((chip->bbt_options & NAND_BBT_NO_OOB_BBM) &&
4321 			!(chip->bbt_options & NAND_BBT_USE_FLASH));
4322 
4323 	if (invalid_ecc_page_accessors(chip)) {
4324 		pr_err("Invalid ECC page accessors setup\n");
4325 		return -EINVAL;
4326 	}
4327 
4328 	if (!(chip->options & NAND_OWN_BUFFERS)) {
4329 		nbuf = kzalloc(sizeof(struct nand_buffers), GFP_KERNEL);
4330 		chip->buffers = nbuf;
4331 	} else {
4332 		if (!chip->buffers)
4333 			return -ENOMEM;
4334 	}
4335 
4336 	/* Set the internal oob buffer location, just after the page data */
4337 	chip->oob_poi = chip->buffers->databuf + mtd->writesize;
4338 
4339 	/*
4340 	 * If no default placement scheme is given, select an appropriate one.
4341 	 */
4342 	if (!ecc->layout && (ecc->mode != NAND_ECC_SOFT_BCH)) {
4343 		switch (mtd->oobsize) {
4344 #ifdef CONFIG_SYS_NAND_DRIVER_ECC_LAYOUT
4345 		case 8:
4346 			ecc->layout = &nand_oob_8;
4347 			break;
4348 		case 16:
4349 			ecc->layout = &nand_oob_16;
4350 			break;
4351 		case 64:
4352 			ecc->layout = &nand_oob_64;
4353 			break;
4354 		case 128:
4355 			ecc->layout = &nand_oob_128;
4356 			break;
4357 #endif
4358 		default:
4359 			pr_warn("No oob scheme defined for oobsize %d\n",
4360 				   mtd->oobsize);
4361 			BUG();
4362 		}
4363 	}
4364 
4365 	if (!chip->write_page)
4366 		chip->write_page = nand_write_page;
4367 
4368 	/*
4369 	 * Check ECC mode, default to software if 3byte/512byte hardware ECC is
4370 	 * selected and we have 256 byte pagesize fallback to software ECC
4371 	 */
4372 
4373 	switch (ecc->mode) {
4374 	case NAND_ECC_HW_OOB_FIRST:
4375 		/* Similar to NAND_ECC_HW, but a separate read_page handle */
4376 		if (!ecc->calculate || !ecc->correct || !ecc->hwctl) {
4377 			pr_warn("No ECC functions supplied; hardware ECC not possible\n");
4378 			BUG();
4379 		}
4380 		if (!ecc->read_page)
4381 			ecc->read_page = nand_read_page_hwecc_oob_first;
4382 
4383 	case NAND_ECC_HW:
4384 		/* Use standard hwecc read page function? */
4385 		if (!ecc->read_page)
4386 			ecc->read_page = nand_read_page_hwecc;
4387 		if (!ecc->write_page)
4388 			ecc->write_page = nand_write_page_hwecc;
4389 		if (!ecc->read_page_raw)
4390 			ecc->read_page_raw = nand_read_page_raw;
4391 		if (!ecc->write_page_raw)
4392 			ecc->write_page_raw = nand_write_page_raw;
4393 		if (!ecc->read_oob)
4394 			ecc->read_oob = nand_read_oob_std;
4395 		if (!ecc->write_oob)
4396 			ecc->write_oob = nand_write_oob_std;
4397 		if (!ecc->read_subpage)
4398 			ecc->read_subpage = nand_read_subpage;
4399 		if (!ecc->write_subpage && ecc->hwctl && ecc->calculate)
4400 			ecc->write_subpage = nand_write_subpage_hwecc;
4401 
4402 	case NAND_ECC_HW_SYNDROME:
4403 		if ((!ecc->calculate || !ecc->correct || !ecc->hwctl) &&
4404 		    (!ecc->read_page ||
4405 		     ecc->read_page == nand_read_page_hwecc ||
4406 		     !ecc->write_page ||
4407 		     ecc->write_page == nand_write_page_hwecc)) {
4408 			pr_warn("No ECC functions supplied; hardware ECC not possible\n");
4409 			BUG();
4410 		}
4411 		/* Use standard syndrome read/write page function? */
4412 		if (!ecc->read_page)
4413 			ecc->read_page = nand_read_page_syndrome;
4414 		if (!ecc->write_page)
4415 			ecc->write_page = nand_write_page_syndrome;
4416 		if (!ecc->read_page_raw)
4417 			ecc->read_page_raw = nand_read_page_raw_syndrome;
4418 		if (!ecc->write_page_raw)
4419 			ecc->write_page_raw = nand_write_page_raw_syndrome;
4420 		if (!ecc->read_oob)
4421 			ecc->read_oob = nand_read_oob_syndrome;
4422 		if (!ecc->write_oob)
4423 			ecc->write_oob = nand_write_oob_syndrome;
4424 
4425 		if (mtd->writesize >= ecc->size) {
4426 			if (!ecc->strength) {
4427 				pr_warn("Driver must set ecc.strength when using hardware ECC\n");
4428 				BUG();
4429 			}
4430 			break;
4431 		}
4432 		pr_warn("%d byte HW ECC not possible on %d byte page size, fallback to SW ECC\n",
4433 			ecc->size, mtd->writesize);
4434 		ecc->mode = NAND_ECC_SOFT;
4435 
4436 	case NAND_ECC_SOFT:
4437 		ecc->calculate = nand_calculate_ecc;
4438 		ecc->correct = nand_correct_data;
4439 		ecc->read_page = nand_read_page_swecc;
4440 		ecc->read_subpage = nand_read_subpage;
4441 		ecc->write_page = nand_write_page_swecc;
4442 		ecc->read_page_raw = nand_read_page_raw;
4443 		ecc->write_page_raw = nand_write_page_raw;
4444 		ecc->read_oob = nand_read_oob_std;
4445 		ecc->write_oob = nand_write_oob_std;
4446 		if (!ecc->size)
4447 			ecc->size = 256;
4448 		ecc->bytes = 3;
4449 		ecc->strength = 1;
4450 		break;
4451 
4452 	case NAND_ECC_SOFT_BCH:
4453 		if (!mtd_nand_has_bch()) {
4454 			pr_warn("CONFIG_MTD_NAND_ECC_BCH not enabled\n");
4455 			BUG();
4456 		}
4457 		ecc->calculate = nand_bch_calculate_ecc;
4458 		ecc->correct = nand_bch_correct_data;
4459 		ecc->read_page = nand_read_page_swecc;
4460 		ecc->read_subpage = nand_read_subpage;
4461 		ecc->write_page = nand_write_page_swecc;
4462 		ecc->read_page_raw = nand_read_page_raw;
4463 		ecc->write_page_raw = nand_write_page_raw;
4464 		ecc->read_oob = nand_read_oob_std;
4465 		ecc->write_oob = nand_write_oob_std;
4466 		/*
4467 		 * Board driver should supply ecc.size and ecc.strength values
4468 		 * to select how many bits are correctable. Otherwise, default
4469 		 * to 4 bits for large page devices.
4470 		 */
4471 		if (!ecc->size && (mtd->oobsize >= 64)) {
4472 			ecc->size = 512;
4473 			ecc->strength = 4;
4474 		}
4475 
4476 		/* See nand_bch_init() for details. */
4477 		ecc->bytes = 0;
4478 		ecc->priv = nand_bch_init(mtd);
4479 		if (!ecc->priv) {
4480 			pr_warn("BCH ECC initialization failed!\n");
4481 			BUG();
4482 		}
4483 		break;
4484 
4485 	case NAND_ECC_NONE:
4486 		pr_warn("NAND_ECC_NONE selected by board driver. This is not recommended!\n");
4487 		ecc->read_page = nand_read_page_raw;
4488 		ecc->write_page = nand_write_page_raw;
4489 		ecc->read_oob = nand_read_oob_std;
4490 		ecc->read_page_raw = nand_read_page_raw;
4491 		ecc->write_page_raw = nand_write_page_raw;
4492 		ecc->write_oob = nand_write_oob_std;
4493 		ecc->size = mtd->writesize;
4494 		ecc->bytes = 0;
4495 		ecc->strength = 0;
4496 		break;
4497 
4498 	default:
4499 		pr_warn("Invalid NAND_ECC_MODE %d\n", ecc->mode);
4500 		BUG();
4501 	}
4502 
4503 	/* For many systems, the standard OOB write also works for raw */
4504 	if (!ecc->read_oob_raw)
4505 		ecc->read_oob_raw = ecc->read_oob;
4506 	if (!ecc->write_oob_raw)
4507 		ecc->write_oob_raw = ecc->write_oob;
4508 
4509 	/*
4510 	 * The number of bytes available for a client to place data into
4511 	 * the out of band area.
4512 	 */
4513 	mtd->oobavail = 0;
4514 	if (ecc->layout) {
4515 		for (i = 0; ecc->layout->oobfree[i].length; i++)
4516 			mtd->oobavail += ecc->layout->oobfree[i].length;
4517 	}
4518 
4519 	/* ECC sanity check: warn if it's too weak */
4520 	if (!nand_ecc_strength_good(mtd))
4521 		pr_warn("WARNING: %s: the ECC used on your system is too weak compared to the one required by the NAND chip\n",
4522 			mtd->name);
4523 
4524 	/*
4525 	 * Set the number of read / write steps for one page depending on ECC
4526 	 * mode.
4527 	 */
4528 	ecc->steps = mtd->writesize / ecc->size;
4529 	if (ecc->steps * ecc->size != mtd->writesize) {
4530 		pr_warn("Invalid ECC parameters\n");
4531 		BUG();
4532 	}
4533 	ecc->total = ecc->steps * ecc->bytes;
4534 
4535 	/* Allow subpage writes up to ecc.steps. Not possible for MLC flash */
4536 	if (!(chip->options & NAND_NO_SUBPAGE_WRITE) && nand_is_slc(chip)) {
4537 		switch (ecc->steps) {
4538 		case 2:
4539 			mtd->subpage_sft = 1;
4540 			break;
4541 		case 4:
4542 		case 8:
4543 		case 16:
4544 			mtd->subpage_sft = 2;
4545 			break;
4546 		}
4547 	}
4548 	chip->subpagesize = mtd->writesize >> mtd->subpage_sft;
4549 
4550 	/* Initialize state */
4551 	chip->state = FL_READY;
4552 
4553 	/* Invalidate the pagebuffer reference */
4554 	chip->pagebuf = -1;
4555 
4556 	/* Large page NAND with SOFT_ECC should support subpage reads */
4557 	switch (ecc->mode) {
4558 	case NAND_ECC_SOFT:
4559 	case NAND_ECC_SOFT_BCH:
4560 		if (chip->page_shift > 9)
4561 			chip->options |= NAND_SUBPAGE_READ;
4562 		break;
4563 
4564 	default:
4565 		break;
4566 	}
4567 
4568 	/* Fill in remaining MTD driver data */
4569 	mtd->type = nand_is_slc(chip) ? MTD_NANDFLASH : MTD_MLCNANDFLASH;
4570 	mtd->flags = (chip->options & NAND_ROM) ? MTD_CAP_ROM :
4571 						MTD_CAP_NANDFLASH;
4572 	mtd->_erase = nand_erase;
4573 	mtd->_panic_write = panic_nand_write;
4574 	mtd->_read_oob = nand_read_oob;
4575 	mtd->_write_oob = nand_write_oob;
4576 	mtd->_sync = nand_sync;
4577 	mtd->_lock = NULL;
4578 	mtd->_unlock = NULL;
4579 	mtd->_block_isreserved = nand_block_isreserved;
4580 	mtd->_block_isbad = nand_block_isbad;
4581 	mtd->_block_markbad = nand_block_markbad;
4582 	mtd->writebufsize = mtd->writesize;
4583 
4584 	/* propagate ecc info to mtd_info */
4585 	mtd->ecclayout = ecc->layout;
4586 	mtd->ecc_strength = ecc->strength;
4587 	mtd->ecc_step_size = ecc->size;
4588 	/*
4589 	 * Initialize bitflip_threshold to its default prior scan_bbt() call.
4590 	 * scan_bbt() might invoke mtd_read(), thus bitflip_threshold must be
4591 	 * properly set.
4592 	 */
4593 	if (!mtd->bitflip_threshold)
4594 		mtd->bitflip_threshold = DIV_ROUND_UP(mtd->ecc_strength * 3, 4);
4595 
4596 	return 0;
4597 }
4598 EXPORT_SYMBOL(nand_scan_tail);
4599 
4600 /**
4601  * nand_scan - [NAND Interface] Scan for the NAND device
4602  * @mtd: MTD device structure
4603  * @maxchips: number of chips to scan for
4604  *
4605  * This fills out all the uninitialized function pointers with the defaults.
4606  * The flash ID is read and the mtd/chip structures are filled with the
4607  * appropriate values.
4608  */
4609 int nand_scan(struct mtd_info *mtd, int maxchips)
4610 {
4611 	int ret;
4612 
4613 	ret = nand_scan_ident(mtd, maxchips, NULL);
4614 	if (!ret)
4615 		ret = nand_scan_tail(mtd);
4616 	return ret;
4617 }
4618 EXPORT_SYMBOL(nand_scan);
4619 
4620 MODULE_LICENSE("GPL");
4621 MODULE_AUTHOR("Steven J. Hill <sjhill@realitydiluted.com>");
4622 MODULE_AUTHOR("Thomas Gleixner <tglx@linutronix.de>");
4623 MODULE_DESCRIPTION("Generic NAND flash driver code");
4624