1 /*
2  * Atmel AT45xxx DataFlash MTD driver for lightweight SPI framework
3  *
4  * Largely derived from at91_dataflash.c:
5  *  Copyright (C) 2003-2005 SAN People (Pty) Ltd
6  *
7  * This program is free software; you can redistribute it and/or
8  * modify it under the terms of the GNU General Public License
9  * as published by the Free Software Foundation; either version
10  * 2 of the License, or (at your option) any later version.
11 */
12 #include <linux/module.h>
13 #include <linux/slab.h>
14 #include <linux/delay.h>
15 #include <linux/device.h>
16 #include <linux/mutex.h>
17 #include <linux/err.h>
18 #include <linux/math64.h>
19 #include <linux/of.h>
20 #include <linux/of_device.h>
21 
22 #include <linux/spi/spi.h>
23 #include <linux/spi/flash.h>
24 
25 #include <linux/mtd/mtd.h>
26 #include <linux/mtd/partitions.h>
27 
28 /*
29  * DataFlash is a kind of SPI flash.  Most AT45 chips have two buffers in
30  * each chip, which may be used for double buffered I/O; but this driver
31  * doesn't (yet) use these for any kind of i/o overlap or prefetching.
32  *
33  * Sometimes DataFlash is packaged in MMC-format cards, although the
34  * MMC stack can't (yet?) distinguish between MMC and DataFlash
35  * protocols during enumeration.
36  */
37 
38 /* reads can bypass the buffers */
39 #define OP_READ_CONTINUOUS	0xE8
40 #define OP_READ_PAGE		0xD2
41 
42 /* group B requests can run even while status reports "busy" */
43 #define OP_READ_STATUS		0xD7	/* group B */
44 
45 /* move data between host and buffer */
46 #define OP_READ_BUFFER1		0xD4	/* group B */
47 #define OP_READ_BUFFER2		0xD6	/* group B */
48 #define OP_WRITE_BUFFER1	0x84	/* group B */
49 #define OP_WRITE_BUFFER2	0x87	/* group B */
50 
51 /* erasing flash */
52 #define OP_ERASE_PAGE		0x81
53 #define OP_ERASE_BLOCK		0x50
54 
55 /* move data between buffer and flash */
56 #define OP_TRANSFER_BUF1	0x53
57 #define OP_TRANSFER_BUF2	0x55
58 #define OP_MREAD_BUFFER1	0xD4
59 #define OP_MREAD_BUFFER2	0xD6
60 #define OP_MWERASE_BUFFER1	0x83
61 #define OP_MWERASE_BUFFER2	0x86
62 #define OP_MWRITE_BUFFER1	0x88	/* sector must be pre-erased */
63 #define OP_MWRITE_BUFFER2	0x89	/* sector must be pre-erased */
64 
65 /* write to buffer, then write-erase to flash */
66 #define OP_PROGRAM_VIA_BUF1	0x82
67 #define OP_PROGRAM_VIA_BUF2	0x85
68 
69 /* compare buffer to flash */
70 #define OP_COMPARE_BUF1		0x60
71 #define OP_COMPARE_BUF2		0x61
72 
73 /* read flash to buffer, then write-erase to flash */
74 #define OP_REWRITE_VIA_BUF1	0x58
75 #define OP_REWRITE_VIA_BUF2	0x59
76 
77 /* newer chips report JEDEC manufacturer and device IDs; chip
78  * serial number and OTP bits; and per-sector writeprotect.
79  */
80 #define OP_READ_ID		0x9F
81 #define OP_READ_SECURITY	0x77
82 #define OP_WRITE_SECURITY_REVC	0x9A
83 #define OP_WRITE_SECURITY	0x9B	/* revision D */
84 
85 #define CFI_MFR_ATMEL		0x1F
86 
87 #define DATAFLASH_SHIFT_EXTID	24
88 #define DATAFLASH_SHIFT_ID	40
89 
90 struct dataflash {
91 	u8			command[4];
92 	char			name[24];
93 
94 	unsigned short		page_offset;	/* offset in flash address */
95 	unsigned int		page_size;	/* of bytes per page */
96 
97 	struct mutex		lock;
98 	struct spi_device	*spi;
99 
100 	struct mtd_info		mtd;
101 };
102 
103 #ifdef CONFIG_OF
104 static const struct of_device_id dataflash_dt_ids[] = {
105 	{ .compatible = "atmel,at45", },
106 	{ .compatible = "atmel,dataflash", },
107 	{ /* sentinel */ }
108 };
109 MODULE_DEVICE_TABLE(of, dataflash_dt_ids);
110 #endif
111 
112 /* ......................................................................... */
113 
114 /*
115  * Return the status of the DataFlash device.
116  */
117 static inline int dataflash_status(struct spi_device *spi)
118 {
119 	/* NOTE:  at45db321c over 25 MHz wants to write
120 	 * a dummy byte after the opcode...
121 	 */
122 	return spi_w8r8(spi, OP_READ_STATUS);
123 }
124 
125 /*
126  * Poll the DataFlash device until it is READY.
127  * This usually takes 5-20 msec or so; more for sector erase.
128  */
129 static int dataflash_waitready(struct spi_device *spi)
130 {
131 	int	status;
132 
133 	for (;;) {
134 		status = dataflash_status(spi);
135 		if (status < 0) {
136 			dev_dbg(&spi->dev, "status %d?\n", status);
137 			status = 0;
138 		}
139 
140 		if (status & (1 << 7))	/* RDY/nBSY */
141 			return status;
142 
143 		usleep_range(3000, 4000);
144 	}
145 }
146 
147 /* ......................................................................... */
148 
149 /*
150  * Erase pages of flash.
151  */
152 static int dataflash_erase(struct mtd_info *mtd, struct erase_info *instr)
153 {
154 	struct dataflash	*priv = mtd->priv;
155 	struct spi_device	*spi = priv->spi;
156 	struct spi_transfer	x = { };
157 	struct spi_message	msg;
158 	unsigned		blocksize = priv->page_size << 3;
159 	u8			*command;
160 	u32			rem;
161 
162 	dev_dbg(&spi->dev, "erase addr=0x%llx len 0x%llx\n",
163 		(long long)instr->addr, (long long)instr->len);
164 
165 	div_u64_rem(instr->len, priv->page_size, &rem);
166 	if (rem)
167 		return -EINVAL;
168 	div_u64_rem(instr->addr, priv->page_size, &rem);
169 	if (rem)
170 		return -EINVAL;
171 
172 	spi_message_init(&msg);
173 
174 	x.tx_buf = command = priv->command;
175 	x.len = 4;
176 	spi_message_add_tail(&x, &msg);
177 
178 	mutex_lock(&priv->lock);
179 	while (instr->len > 0) {
180 		unsigned int	pageaddr;
181 		int		status;
182 		int		do_block;
183 
184 		/* Calculate flash page address; use block erase (for speed) if
185 		 * we're at a block boundary and need to erase the whole block.
186 		 */
187 		pageaddr = div_u64(instr->addr, priv->page_size);
188 		do_block = (pageaddr & 0x7) == 0 && instr->len >= blocksize;
189 		pageaddr = pageaddr << priv->page_offset;
190 
191 		command[0] = do_block ? OP_ERASE_BLOCK : OP_ERASE_PAGE;
192 		command[1] = (u8)(pageaddr >> 16);
193 		command[2] = (u8)(pageaddr >> 8);
194 		command[3] = 0;
195 
196 		dev_dbg(&spi->dev, "ERASE %s: (%x) %x %x %x [%i]\n",
197 			do_block ? "block" : "page",
198 			command[0], command[1], command[2], command[3],
199 			pageaddr);
200 
201 		status = spi_sync(spi, &msg);
202 		(void) dataflash_waitready(spi);
203 
204 		if (status < 0) {
205 			dev_err(&spi->dev, "erase %x, err %d\n",
206 				pageaddr, status);
207 			/* REVISIT:  can retry instr->retries times; or
208 			 * giveup and instr->fail_addr = instr->addr;
209 			 */
210 			continue;
211 		}
212 
213 		if (do_block) {
214 			instr->addr += blocksize;
215 			instr->len -= blocksize;
216 		} else {
217 			instr->addr += priv->page_size;
218 			instr->len -= priv->page_size;
219 		}
220 	}
221 	mutex_unlock(&priv->lock);
222 
223 	return 0;
224 }
225 
226 /*
227  * Read from the DataFlash device.
228  *   from   : Start offset in flash device
229  *   len    : Amount to read
230  *   retlen : About of data actually read
231  *   buf    : Buffer containing the data
232  */
233 static int dataflash_read(struct mtd_info *mtd, loff_t from, size_t len,
234 			       size_t *retlen, u_char *buf)
235 {
236 	struct dataflash	*priv = mtd->priv;
237 	struct spi_transfer	x[2] = { };
238 	struct spi_message	msg;
239 	unsigned int		addr;
240 	u8			*command;
241 	int			status;
242 
243 	dev_dbg(&priv->spi->dev, "read 0x%x..0x%x\n",
244 		  (unsigned int)from, (unsigned int)(from + len));
245 
246 	/* Calculate flash page/byte address */
247 	addr = (((unsigned)from / priv->page_size) << priv->page_offset)
248 		+ ((unsigned)from % priv->page_size);
249 
250 	command = priv->command;
251 
252 	dev_dbg(&priv->spi->dev, "READ: (%x) %x %x %x\n",
253 		command[0], command[1], command[2], command[3]);
254 
255 	spi_message_init(&msg);
256 
257 	x[0].tx_buf = command;
258 	x[0].len = 8;
259 	spi_message_add_tail(&x[0], &msg);
260 
261 	x[1].rx_buf = buf;
262 	x[1].len = len;
263 	spi_message_add_tail(&x[1], &msg);
264 
265 	mutex_lock(&priv->lock);
266 
267 	/* Continuous read, max clock = f(car) which may be less than
268 	 * the peak rate available.  Some chips support commands with
269 	 * fewer "don't care" bytes.  Both buffers stay unchanged.
270 	 */
271 	command[0] = OP_READ_CONTINUOUS;
272 	command[1] = (u8)(addr >> 16);
273 	command[2] = (u8)(addr >> 8);
274 	command[3] = (u8)(addr >> 0);
275 	/* plus 4 "don't care" bytes */
276 
277 	status = spi_sync(priv->spi, &msg);
278 	mutex_unlock(&priv->lock);
279 
280 	if (status >= 0) {
281 		*retlen = msg.actual_length - 8;
282 		status = 0;
283 	} else
284 		dev_dbg(&priv->spi->dev, "read %x..%x --> %d\n",
285 			(unsigned)from, (unsigned)(from + len),
286 			status);
287 	return status;
288 }
289 
290 /*
291  * Write to the DataFlash device.
292  *   to     : Start offset in flash device
293  *   len    : Amount to write
294  *   retlen : Amount of data actually written
295  *   buf    : Buffer containing the data
296  */
297 static int dataflash_write(struct mtd_info *mtd, loff_t to, size_t len,
298 				size_t * retlen, const u_char * buf)
299 {
300 	struct dataflash	*priv = mtd->priv;
301 	struct spi_device	*spi = priv->spi;
302 	struct spi_transfer	x[2] = { };
303 	struct spi_message	msg;
304 	unsigned int		pageaddr, addr, offset, writelen;
305 	size_t			remaining = len;
306 	u_char			*writebuf = (u_char *) buf;
307 	int			status = -EINVAL;
308 	u8			*command;
309 
310 	dev_dbg(&spi->dev, "write 0x%x..0x%x\n",
311 		(unsigned int)to, (unsigned int)(to + len));
312 
313 	spi_message_init(&msg);
314 
315 	x[0].tx_buf = command = priv->command;
316 	x[0].len = 4;
317 	spi_message_add_tail(&x[0], &msg);
318 
319 	pageaddr = ((unsigned)to / priv->page_size);
320 	offset = ((unsigned)to % priv->page_size);
321 	if (offset + len > priv->page_size)
322 		writelen = priv->page_size - offset;
323 	else
324 		writelen = len;
325 
326 	mutex_lock(&priv->lock);
327 	while (remaining > 0) {
328 		dev_dbg(&spi->dev, "write @ %i:%i len=%i\n",
329 			pageaddr, offset, writelen);
330 
331 		/* REVISIT:
332 		 * (a) each page in a sector must be rewritten at least
333 		 *     once every 10K sibling erase/program operations.
334 		 * (b) for pages that are already erased, we could
335 		 *     use WRITE+MWRITE not PROGRAM for ~30% speedup.
336 		 * (c) WRITE to buffer could be done while waiting for
337 		 *     a previous MWRITE/MWERASE to complete ...
338 		 * (d) error handling here seems to be mostly missing.
339 		 *
340 		 * Two persistent bits per page, plus a per-sector counter,
341 		 * could support (a) and (b) ... we might consider using
342 		 * the second half of sector zero, which is just one block,
343 		 * to track that state.  (On AT91, that sector should also
344 		 * support boot-from-DataFlash.)
345 		 */
346 
347 		addr = pageaddr << priv->page_offset;
348 
349 		/* (1) Maybe transfer partial page to Buffer1 */
350 		if (writelen != priv->page_size) {
351 			command[0] = OP_TRANSFER_BUF1;
352 			command[1] = (addr & 0x00FF0000) >> 16;
353 			command[2] = (addr & 0x0000FF00) >> 8;
354 			command[3] = 0;
355 
356 			dev_dbg(&spi->dev, "TRANSFER: (%x) %x %x %x\n",
357 				command[0], command[1], command[2], command[3]);
358 
359 			status = spi_sync(spi, &msg);
360 			if (status < 0)
361 				dev_dbg(&spi->dev, "xfer %u -> %d\n",
362 					addr, status);
363 
364 			(void) dataflash_waitready(priv->spi);
365 		}
366 
367 		/* (2) Program full page via Buffer1 */
368 		addr += offset;
369 		command[0] = OP_PROGRAM_VIA_BUF1;
370 		command[1] = (addr & 0x00FF0000) >> 16;
371 		command[2] = (addr & 0x0000FF00) >> 8;
372 		command[3] = (addr & 0x000000FF);
373 
374 		dev_dbg(&spi->dev, "PROGRAM: (%x) %x %x %x\n",
375 			command[0], command[1], command[2], command[3]);
376 
377 		x[1].tx_buf = writebuf;
378 		x[1].len = writelen;
379 		spi_message_add_tail(x + 1, &msg);
380 		status = spi_sync(spi, &msg);
381 		spi_transfer_del(x + 1);
382 		if (status < 0)
383 			dev_dbg(&spi->dev, "pgm %u/%u -> %d\n",
384 				addr, writelen, status);
385 
386 		(void) dataflash_waitready(priv->spi);
387 
388 
389 #ifdef CONFIG_MTD_DATAFLASH_WRITE_VERIFY
390 
391 		/* (3) Compare to Buffer1 */
392 		addr = pageaddr << priv->page_offset;
393 		command[0] = OP_COMPARE_BUF1;
394 		command[1] = (addr & 0x00FF0000) >> 16;
395 		command[2] = (addr & 0x0000FF00) >> 8;
396 		command[3] = 0;
397 
398 		dev_dbg(&spi->dev, "COMPARE: (%x) %x %x %x\n",
399 			command[0], command[1], command[2], command[3]);
400 
401 		status = spi_sync(spi, &msg);
402 		if (status < 0)
403 			dev_dbg(&spi->dev, "compare %u -> %d\n",
404 				addr, status);
405 
406 		status = dataflash_waitready(priv->spi);
407 
408 		/* Check result of the compare operation */
409 		if (status & (1 << 6)) {
410 			dev_err(&spi->dev, "compare page %u, err %d\n",
411 				pageaddr, status);
412 			remaining = 0;
413 			status = -EIO;
414 			break;
415 		} else
416 			status = 0;
417 
418 #endif	/* CONFIG_MTD_DATAFLASH_WRITE_VERIFY */
419 
420 		remaining = remaining - writelen;
421 		pageaddr++;
422 		offset = 0;
423 		writebuf += writelen;
424 		*retlen += writelen;
425 
426 		if (remaining > priv->page_size)
427 			writelen = priv->page_size;
428 		else
429 			writelen = remaining;
430 	}
431 	mutex_unlock(&priv->lock);
432 
433 	return status;
434 }
435 
436 /* ......................................................................... */
437 
438 #ifdef CONFIG_MTD_DATAFLASH_OTP
439 
440 static int dataflash_get_otp_info(struct mtd_info *mtd, size_t len,
441 				  size_t *retlen, struct otp_info *info)
442 {
443 	/* Report both blocks as identical:  bytes 0..64, locked.
444 	 * Unless the user block changed from all-ones, we can't
445 	 * tell whether it's still writable; so we assume it isn't.
446 	 */
447 	info->start = 0;
448 	info->length = 64;
449 	info->locked = 1;
450 	*retlen = sizeof(*info);
451 	return 0;
452 }
453 
454 static ssize_t otp_read(struct spi_device *spi, unsigned base,
455 		u8 *buf, loff_t off, size_t len)
456 {
457 	struct spi_message	m;
458 	size_t			l;
459 	u8			*scratch;
460 	struct spi_transfer	t;
461 	int			status;
462 
463 	if (off > 64)
464 		return -EINVAL;
465 
466 	if ((off + len) > 64)
467 		len = 64 - off;
468 
469 	spi_message_init(&m);
470 
471 	l = 4 + base + off + len;
472 	scratch = kzalloc(l, GFP_KERNEL);
473 	if (!scratch)
474 		return -ENOMEM;
475 
476 	/* OUT: OP_READ_SECURITY, 3 don't-care bytes, zeroes
477 	 * IN:  ignore 4 bytes, data bytes 0..N (max 127)
478 	 */
479 	scratch[0] = OP_READ_SECURITY;
480 
481 	memset(&t, 0, sizeof t);
482 	t.tx_buf = scratch;
483 	t.rx_buf = scratch;
484 	t.len = l;
485 	spi_message_add_tail(&t, &m);
486 
487 	dataflash_waitready(spi);
488 
489 	status = spi_sync(spi, &m);
490 	if (status >= 0) {
491 		memcpy(buf, scratch + 4 + base + off, len);
492 		status = len;
493 	}
494 
495 	kfree(scratch);
496 	return status;
497 }
498 
499 static int dataflash_read_fact_otp(struct mtd_info *mtd,
500 		loff_t from, size_t len, size_t *retlen, u_char *buf)
501 {
502 	struct dataflash	*priv = mtd->priv;
503 	int			status;
504 
505 	/* 64 bytes, from 0..63 ... start at 64 on-chip */
506 	mutex_lock(&priv->lock);
507 	status = otp_read(priv->spi, 64, buf, from, len);
508 	mutex_unlock(&priv->lock);
509 
510 	if (status < 0)
511 		return status;
512 	*retlen = status;
513 	return 0;
514 }
515 
516 static int dataflash_read_user_otp(struct mtd_info *mtd,
517 		loff_t from, size_t len, size_t *retlen, u_char *buf)
518 {
519 	struct dataflash	*priv = mtd->priv;
520 	int			status;
521 
522 	/* 64 bytes, from 0..63 ... start at 0 on-chip */
523 	mutex_lock(&priv->lock);
524 	status = otp_read(priv->spi, 0, buf, from, len);
525 	mutex_unlock(&priv->lock);
526 
527 	if (status < 0)
528 		return status;
529 	*retlen = status;
530 	return 0;
531 }
532 
533 static int dataflash_write_user_otp(struct mtd_info *mtd,
534 		loff_t from, size_t len, size_t *retlen, u_char *buf)
535 {
536 	struct spi_message	m;
537 	const size_t		l = 4 + 64;
538 	u8			*scratch;
539 	struct spi_transfer	t;
540 	struct dataflash	*priv = mtd->priv;
541 	int			status;
542 
543 	if (from >= 64) {
544 		/*
545 		 * Attempting to write beyond the end of OTP memory,
546 		 * no data can be written.
547 		 */
548 		*retlen = 0;
549 		return 0;
550 	}
551 
552 	/* Truncate the write to fit into OTP memory. */
553 	if ((from + len) > 64)
554 		len = 64 - from;
555 
556 	/* OUT: OP_WRITE_SECURITY, 3 zeroes, 64 data-or-zero bytes
557 	 * IN:  ignore all
558 	 */
559 	scratch = kzalloc(l, GFP_KERNEL);
560 	if (!scratch)
561 		return -ENOMEM;
562 	scratch[0] = OP_WRITE_SECURITY;
563 	memcpy(scratch + 4 + from, buf, len);
564 
565 	spi_message_init(&m);
566 
567 	memset(&t, 0, sizeof t);
568 	t.tx_buf = scratch;
569 	t.len = l;
570 	spi_message_add_tail(&t, &m);
571 
572 	/* Write the OTP bits, if they've not yet been written.
573 	 * This modifies SRAM buffer1.
574 	 */
575 	mutex_lock(&priv->lock);
576 	dataflash_waitready(priv->spi);
577 	status = spi_sync(priv->spi, &m);
578 	mutex_unlock(&priv->lock);
579 
580 	kfree(scratch);
581 
582 	if (status >= 0) {
583 		status = 0;
584 		*retlen = len;
585 	}
586 	return status;
587 }
588 
589 static char *otp_setup(struct mtd_info *device, char revision)
590 {
591 	device->_get_fact_prot_info = dataflash_get_otp_info;
592 	device->_read_fact_prot_reg = dataflash_read_fact_otp;
593 	device->_get_user_prot_info = dataflash_get_otp_info;
594 	device->_read_user_prot_reg = dataflash_read_user_otp;
595 
596 	/* rev c parts (at45db321c and at45db1281 only!) use a
597 	 * different write procedure; not (yet?) implemented.
598 	 */
599 	if (revision > 'c')
600 		device->_write_user_prot_reg = dataflash_write_user_otp;
601 
602 	return ", OTP";
603 }
604 
605 #else
606 
607 static char *otp_setup(struct mtd_info *device, char revision)
608 {
609 	return " (OTP)";
610 }
611 
612 #endif
613 
614 /* ......................................................................... */
615 
616 /*
617  * Register DataFlash device with MTD subsystem.
618  */
619 static int add_dataflash_otp(struct spi_device *spi, char *name, int nr_pages,
620 			     int pagesize, int pageoffset, char revision)
621 {
622 	struct dataflash		*priv;
623 	struct mtd_info			*device;
624 	struct flash_platform_data	*pdata = dev_get_platdata(&spi->dev);
625 	char				*otp_tag = "";
626 	int				err = 0;
627 
628 	priv = kzalloc(sizeof *priv, GFP_KERNEL);
629 	if (!priv)
630 		return -ENOMEM;
631 
632 	mutex_init(&priv->lock);
633 	priv->spi = spi;
634 	priv->page_size = pagesize;
635 	priv->page_offset = pageoffset;
636 
637 	/* name must be usable with cmdlinepart */
638 	sprintf(priv->name, "spi%d.%d-%s",
639 			spi->master->bus_num, spi->chip_select,
640 			name);
641 
642 	device = &priv->mtd;
643 	device->name = (pdata && pdata->name) ? pdata->name : priv->name;
644 	device->size = nr_pages * pagesize;
645 	device->erasesize = pagesize;
646 	device->writesize = pagesize;
647 	device->type = MTD_DATAFLASH;
648 	device->flags = MTD_WRITEABLE;
649 	device->_erase = dataflash_erase;
650 	device->_read = dataflash_read;
651 	device->_write = dataflash_write;
652 	device->priv = priv;
653 
654 	device->dev.parent = &spi->dev;
655 	mtd_set_of_node(device, spi->dev.of_node);
656 
657 	if (revision >= 'c')
658 		otp_tag = otp_setup(device, revision);
659 
660 	dev_info(&spi->dev, "%s (%lld KBytes) pagesize %d bytes%s\n",
661 			name, (long long)((device->size + 1023) >> 10),
662 			pagesize, otp_tag);
663 	spi_set_drvdata(spi, priv);
664 
665 	err = mtd_device_register(device,
666 			pdata ? pdata->parts : NULL,
667 			pdata ? pdata->nr_parts : 0);
668 
669 	if (!err)
670 		return 0;
671 
672 	kfree(priv);
673 	return err;
674 }
675 
676 static inline int add_dataflash(struct spi_device *spi, char *name,
677 				int nr_pages, int pagesize, int pageoffset)
678 {
679 	return add_dataflash_otp(spi, name, nr_pages, pagesize,
680 			pageoffset, 0);
681 }
682 
683 struct flash_info {
684 	char		*name;
685 
686 	/* JEDEC id has a high byte of zero plus three data bytes:
687 	 * the manufacturer id, then a two byte device id.
688 	 */
689 	u64		jedec_id;
690 
691 	/* The size listed here is what works with OP_ERASE_PAGE. */
692 	unsigned	nr_pages;
693 	u16		pagesize;
694 	u16		pageoffset;
695 
696 	u16		flags;
697 #define SUP_EXTID	0x0004		/* supports extended ID data */
698 #define SUP_POW2PS	0x0002		/* supports 2^N byte pages */
699 #define IS_POW2PS	0x0001		/* uses 2^N byte pages */
700 };
701 
702 static struct flash_info dataflash_data[] = {
703 
704 	/*
705 	 * NOTE:  chips with SUP_POW2PS (rev D and up) need two entries,
706 	 * one with IS_POW2PS and the other without.  The entry with the
707 	 * non-2^N byte page size can't name exact chip revisions without
708 	 * losing backwards compatibility for cmdlinepart.
709 	 *
710 	 * These newer chips also support 128-byte security registers (with
711 	 * 64 bytes one-time-programmable) and software write-protection.
712 	 */
713 	{ "AT45DB011B",  0x1f2200, 512, 264, 9, SUP_POW2PS},
714 	{ "at45db011d",  0x1f2200, 512, 256, 8, SUP_POW2PS | IS_POW2PS},
715 
716 	{ "AT45DB021B",  0x1f2300, 1024, 264, 9, SUP_POW2PS},
717 	{ "at45db021d",  0x1f2300, 1024, 256, 8, SUP_POW2PS | IS_POW2PS},
718 
719 	{ "AT45DB041x",  0x1f2400, 2048, 264, 9, SUP_POW2PS},
720 	{ "at45db041d",  0x1f2400, 2048, 256, 8, SUP_POW2PS | IS_POW2PS},
721 
722 	{ "AT45DB081B",  0x1f2500, 4096, 264, 9, SUP_POW2PS},
723 	{ "at45db081d",  0x1f2500, 4096, 256, 8, SUP_POW2PS | IS_POW2PS},
724 
725 	{ "AT45DB161x",  0x1f2600, 4096, 528, 10, SUP_POW2PS},
726 	{ "at45db161d",  0x1f2600, 4096, 512, 9, SUP_POW2PS | IS_POW2PS},
727 
728 	{ "AT45DB321x",  0x1f2700, 8192, 528, 10, 0},		/* rev C */
729 
730 	{ "AT45DB321x",  0x1f2701, 8192, 528, 10, SUP_POW2PS},
731 	{ "at45db321d",  0x1f2701, 8192, 512, 9, SUP_POW2PS | IS_POW2PS},
732 
733 	{ "AT45DB642x",  0x1f2800, 8192, 1056, 11, SUP_POW2PS},
734 	{ "at45db642d",  0x1f2800, 8192, 1024, 10, SUP_POW2PS | IS_POW2PS},
735 
736 	{ "AT45DB641E",  0x1f28000100, 32768, 264, 9, SUP_EXTID | SUP_POW2PS},
737 	{ "at45db641e",  0x1f28000100, 32768, 256, 8, SUP_EXTID | SUP_POW2PS | IS_POW2PS},
738 };
739 
740 static struct flash_info *jedec_lookup(struct spi_device *spi,
741 				       u64 jedec, bool use_extid)
742 {
743 	struct flash_info *info;
744 	int status;
745 
746 	for (info = dataflash_data;
747 	     info < dataflash_data + ARRAY_SIZE(dataflash_data);
748 	     info++) {
749 		if (use_extid && !(info->flags & SUP_EXTID))
750 			continue;
751 
752 		if (info->jedec_id == jedec) {
753 			dev_dbg(&spi->dev, "OTP, sector protect%s\n",
754 				(info->flags & SUP_POW2PS) ?
755 				", binary pagesize" : "");
756 			if (info->flags & SUP_POW2PS) {
757 				status = dataflash_status(spi);
758 				if (status < 0) {
759 					dev_dbg(&spi->dev, "status error %d\n",
760 						status);
761 					return ERR_PTR(status);
762 				}
763 				if (status & 0x1) {
764 					if (info->flags & IS_POW2PS)
765 						return info;
766 				} else {
767 					if (!(info->flags & IS_POW2PS))
768 						return info;
769 				}
770 			} else
771 				return info;
772 		}
773 	}
774 
775 	return ERR_PTR(-ENODEV);
776 }
777 
778 static struct flash_info *jedec_probe(struct spi_device *spi)
779 {
780 	int ret;
781 	u8 code = OP_READ_ID;
782 	u64 jedec;
783 	u8 id[sizeof(jedec)] = {0};
784 	const unsigned int id_size = 5;
785 	struct flash_info *info;
786 
787 	/*
788 	 * JEDEC also defines an optional "extended device information"
789 	 * string for after vendor-specific data, after the three bytes
790 	 * we use here.  Supporting some chips might require using it.
791 	 *
792 	 * If the vendor ID isn't Atmel's (0x1f), assume this call failed.
793 	 * That's not an error; only rev C and newer chips handle it, and
794 	 * only Atmel sells these chips.
795 	 */
796 	ret = spi_write_then_read(spi, &code, 1, id, id_size);
797 	if (ret < 0) {
798 		dev_dbg(&spi->dev, "error %d reading JEDEC ID\n", ret);
799 		return ERR_PTR(ret);
800 	}
801 
802 	if (id[0] != CFI_MFR_ATMEL)
803 		return NULL;
804 
805 	jedec = be64_to_cpup((__be64 *)id);
806 
807 	/*
808 	 * First, try to match device using extended device
809 	 * information
810 	 */
811 	info = jedec_lookup(spi, jedec >> DATAFLASH_SHIFT_EXTID, true);
812 	if (!IS_ERR(info))
813 		return info;
814 	/*
815 	 * If that fails, make another pass using regular ID
816 	 * information
817 	 */
818 	info = jedec_lookup(spi, jedec >> DATAFLASH_SHIFT_ID, false);
819 	if (!IS_ERR(info))
820 		return info;
821 	/*
822 	 * Treat other chips as errors ... we won't know the right page
823 	 * size (it might be binary) even when we can tell which density
824 	 * class is involved (legacy chip id scheme).
825 	 */
826 	dev_warn(&spi->dev, "JEDEC id %016llx not handled\n", jedec);
827 	return ERR_PTR(-ENODEV);
828 }
829 
830 /*
831  * Detect and initialize DataFlash device, using JEDEC IDs on newer chips
832  * or else the ID code embedded in the status bits:
833  *
834  *   Device      Density         ID code          #Pages PageSize  Offset
835  *   AT45DB011B  1Mbit   (128K)  xx0011xx (0x0c)    512    264      9
836  *   AT45DB021B  2Mbit   (256K)  xx0101xx (0x14)   1024    264      9
837  *   AT45DB041B  4Mbit   (512K)  xx0111xx (0x1c)   2048    264      9
838  *   AT45DB081B  8Mbit   (1M)    xx1001xx (0x24)   4096    264      9
839  *   AT45DB0161B 16Mbit  (2M)    xx1011xx (0x2c)   4096    528     10
840  *   AT45DB0321B 32Mbit  (4M)    xx1101xx (0x34)   8192    528     10
841  *   AT45DB0642  64Mbit  (8M)    xx111xxx (0x3c)   8192   1056     11
842  *   AT45DB1282  128Mbit (16M)   xx0100xx (0x10)  16384   1056     11
843  */
844 static int dataflash_probe(struct spi_device *spi)
845 {
846 	int status;
847 	struct flash_info	*info;
848 
849 	/*
850 	 * Try to detect dataflash by JEDEC ID.
851 	 * If it succeeds we know we have either a C or D part.
852 	 * D will support power of 2 pagesize option.
853 	 * Both support the security register, though with different
854 	 * write procedures.
855 	 */
856 	info = jedec_probe(spi);
857 	if (IS_ERR(info))
858 		return PTR_ERR(info);
859 	if (info != NULL)
860 		return add_dataflash_otp(spi, info->name, info->nr_pages,
861 				info->pagesize, info->pageoffset,
862 				(info->flags & SUP_POW2PS) ? 'd' : 'c');
863 
864 	/*
865 	 * Older chips support only legacy commands, identifing
866 	 * capacity using bits in the status byte.
867 	 */
868 	status = dataflash_status(spi);
869 	if (status <= 0 || status == 0xff) {
870 		dev_dbg(&spi->dev, "status error %d\n", status);
871 		if (status == 0 || status == 0xff)
872 			status = -ENODEV;
873 		return status;
874 	}
875 
876 	/* if there's a device there, assume it's dataflash.
877 	 * board setup should have set spi->max_speed_max to
878 	 * match f(car) for continuous reads, mode 0 or 3.
879 	 */
880 	switch (status & 0x3c) {
881 	case 0x0c:	/* 0 0 1 1 x x */
882 		status = add_dataflash(spi, "AT45DB011B", 512, 264, 9);
883 		break;
884 	case 0x14:	/* 0 1 0 1 x x */
885 		status = add_dataflash(spi, "AT45DB021B", 1024, 264, 9);
886 		break;
887 	case 0x1c:	/* 0 1 1 1 x x */
888 		status = add_dataflash(spi, "AT45DB041x", 2048, 264, 9);
889 		break;
890 	case 0x24:	/* 1 0 0 1 x x */
891 		status = add_dataflash(spi, "AT45DB081B", 4096, 264, 9);
892 		break;
893 	case 0x2c:	/* 1 0 1 1 x x */
894 		status = add_dataflash(spi, "AT45DB161x", 4096, 528, 10);
895 		break;
896 	case 0x34:	/* 1 1 0 1 x x */
897 		status = add_dataflash(spi, "AT45DB321x", 8192, 528, 10);
898 		break;
899 	case 0x38:	/* 1 1 1 x x x */
900 	case 0x3c:
901 		status = add_dataflash(spi, "AT45DB642x", 8192, 1056, 11);
902 		break;
903 	/* obsolete AT45DB1282 not (yet?) supported */
904 	default:
905 		dev_info(&spi->dev, "unsupported device (%x)\n",
906 				status & 0x3c);
907 		status = -ENODEV;
908 	}
909 
910 	if (status < 0)
911 		dev_dbg(&spi->dev, "add_dataflash --> %d\n", status);
912 
913 	return status;
914 }
915 
916 static int dataflash_remove(struct spi_device *spi)
917 {
918 	struct dataflash	*flash = spi_get_drvdata(spi);
919 	int			status;
920 
921 	dev_dbg(&spi->dev, "remove\n");
922 
923 	status = mtd_device_unregister(&flash->mtd);
924 	if (status == 0)
925 		kfree(flash);
926 	return status;
927 }
928 
929 static struct spi_driver dataflash_driver = {
930 	.driver = {
931 		.name		= "mtd_dataflash",
932 		.of_match_table = of_match_ptr(dataflash_dt_ids),
933 	},
934 
935 	.probe		= dataflash_probe,
936 	.remove		= dataflash_remove,
937 
938 	/* FIXME:  investigate suspend and resume... */
939 };
940 
941 module_spi_driver(dataflash_driver);
942 
943 MODULE_LICENSE("GPL");
944 MODULE_AUTHOR("Andrew Victor, David Brownell");
945 MODULE_DESCRIPTION("MTD DataFlash driver");
946 MODULE_ALIAS("spi:mtd_dataflash");
947