xref: /openbmc/u-boot/drivers/mtd/spi/spi-nor-tiny.c (revision 57ade079)
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Based on m25p80.c, by Mike Lavender (mike@steroidmicros.com), with
4  * influence from lart.c (Abraham Van Der Merwe) and mtd_dataflash.c
5  *
6  * Copyright (C) 2005, Intec Automation Inc.
7  * Copyright (C) 2014, Freescale Semiconductor, Inc.
8  *
9  * Synced from Linux v4.19
10  */
11 
12 #include <common.h>
13 #include <linux/err.h>
14 #include <linux/errno.h>
15 #include <linux/log2.h>
16 #include <linux/math64.h>
17 #include <linux/sizes.h>
18 
19 #include <linux/mtd/mtd.h>
20 #include <linux/mtd/spi-nor.h>
21 #include <spi-mem.h>
22 #include <spi.h>
23 
24 #include "sf_internal.h"
25 
26 /* Define max times to check status register before we give up. */
27 
28 /*
29  * For everything but full-chip erase; probably could be much smaller, but kept
30  * around for safety for now
31  */
32 
33 #define HZ					CONFIG_SYS_HZ
34 
35 #define DEFAULT_READY_WAIT_JIFFIES		(40UL * HZ)
36 
37 static int spi_nor_read_write_reg(struct spi_nor *nor, struct spi_mem_op
38 		*op, void *buf)
39 {
40 	if (op->data.dir == SPI_MEM_DATA_IN)
41 		op->data.buf.in = buf;
42 	else
43 		op->data.buf.out = buf;
44 	return spi_mem_exec_op(nor->spi, op);
45 }
46 
47 static int spi_nor_read_reg(struct spi_nor *nor, u8 code, u8 *val, int len)
48 {
49 	struct spi_mem_op op = SPI_MEM_OP(SPI_MEM_OP_CMD(code, 1),
50 					  SPI_MEM_OP_NO_ADDR,
51 					  SPI_MEM_OP_NO_DUMMY,
52 					  SPI_MEM_OP_DATA_IN(len, NULL, 1));
53 	int ret;
54 
55 	ret = spi_nor_read_write_reg(nor, &op, val);
56 	if (ret < 0)
57 		dev_dbg(&flash->spimem->spi->dev, "error %d reading %x\n", ret,
58 			code);
59 
60 	return ret;
61 }
62 
63 static int spi_nor_write_reg(struct spi_nor *nor, u8 opcode, u8 *buf, int len)
64 {
65 	struct spi_mem_op op = SPI_MEM_OP(SPI_MEM_OP_CMD(opcode, 1),
66 					  SPI_MEM_OP_NO_ADDR,
67 					  SPI_MEM_OP_NO_DUMMY,
68 					  SPI_MEM_OP_DATA_OUT(len, NULL, 1));
69 
70 	return spi_nor_read_write_reg(nor, &op, buf);
71 }
72 
73 static ssize_t spi_nor_read_data(struct spi_nor *nor, loff_t from, size_t len,
74 				 u_char *buf)
75 {
76 	struct spi_mem_op op =
77 			SPI_MEM_OP(SPI_MEM_OP_CMD(nor->read_opcode, 1),
78 				   SPI_MEM_OP_ADDR(nor->addr_width, from, 1),
79 				   SPI_MEM_OP_DUMMY(nor->read_dummy, 1),
80 				   SPI_MEM_OP_DATA_IN(len, buf, 1));
81 	size_t remaining = len;
82 	int ret;
83 
84 	/* get transfer protocols. */
85 	op.cmd.buswidth = spi_nor_get_protocol_inst_nbits(nor->read_proto);
86 	op.addr.buswidth = spi_nor_get_protocol_addr_nbits(nor->read_proto);
87 	op.dummy.buswidth = op.addr.buswidth;
88 	op.data.buswidth = spi_nor_get_protocol_data_nbits(nor->read_proto);
89 
90 	/* convert the dummy cycles to the number of bytes */
91 	op.dummy.nbytes = (nor->read_dummy * op.dummy.buswidth) / 8;
92 
93 	while (remaining) {
94 		op.data.nbytes = remaining < UINT_MAX ? remaining : UINT_MAX;
95 		ret = spi_mem_adjust_op_size(nor->spi, &op);
96 		if (ret)
97 			return ret;
98 
99 		ret = spi_mem_exec_op(nor->spi, &op);
100 		if (ret)
101 			return ret;
102 
103 		op.addr.val += op.data.nbytes;
104 		remaining -= op.data.nbytes;
105 		op.data.buf.in += op.data.nbytes;
106 	}
107 
108 	return len;
109 }
110 
111 #if defined(CONFIG_SPI_FLASH_SPANSION) || defined(CONFIG_SPI_FLASH_WINBOND)
112 /*
113  * Read configuration register, returning its value in the
114  * location. Return the configuration register value.
115  * Returns negative if error occurred.
116  */
117 static int read_cr(struct spi_nor *nor)
118 {
119 	int ret;
120 	u8 val;
121 
122 	ret = spi_nor_read_reg(nor, SPINOR_OP_RDCR, &val, 1);
123 	if (ret < 0) {
124 		dev_dbg(nor->dev, "error %d reading CR\n", ret);
125 		return ret;
126 	}
127 
128 	return val;
129 }
130 #endif
131 
132 /*
133  * Write status register 1 byte
134  * Returns negative if error occurred.
135  */
136 static inline int write_sr(struct spi_nor *nor, u8 val)
137 {
138 	nor->cmd_buf[0] = val;
139 	return spi_nor_write_reg(nor, SPINOR_OP_WRSR, nor->cmd_buf, 1);
140 }
141 
142 /*
143  * Set write enable latch with Write Enable command.
144  * Returns negative if error occurred.
145  */
146 static inline int write_enable(struct spi_nor *nor)
147 {
148 	return spi_nor_write_reg(nor, SPINOR_OP_WREN, NULL, 0);
149 }
150 
151 /*
152  * Send write disable instruction to the chip.
153  */
154 static inline int write_disable(struct spi_nor *nor)
155 {
156 	return spi_nor_write_reg(nor, SPINOR_OP_WRDI, NULL, 0);
157 }
158 
159 static inline struct spi_nor *mtd_to_spi_nor(struct mtd_info *mtd)
160 {
161 	return mtd->priv;
162 }
163 
164 static u8 spi_nor_convert_opcode(u8 opcode, const u8 table[][2], size_t size)
165 {
166 	size_t i;
167 
168 	for (i = 0; i < size; i++)
169 		if (table[i][0] == opcode)
170 			return table[i][1];
171 
172 	/* No conversion found, keep input op code. */
173 	return opcode;
174 }
175 
176 static inline u8 spi_nor_convert_3to4_read(u8 opcode)
177 {
178 	static const u8 spi_nor_3to4_read[][2] = {
179 		{ SPINOR_OP_READ,	SPINOR_OP_READ_4B },
180 		{ SPINOR_OP_READ_FAST,	SPINOR_OP_READ_FAST_4B },
181 		{ SPINOR_OP_READ_1_1_2,	SPINOR_OP_READ_1_1_2_4B },
182 		{ SPINOR_OP_READ_1_2_2,	SPINOR_OP_READ_1_2_2_4B },
183 		{ SPINOR_OP_READ_1_1_4,	SPINOR_OP_READ_1_1_4_4B },
184 		{ SPINOR_OP_READ_1_4_4,	SPINOR_OP_READ_1_4_4_4B },
185 	};
186 
187 	return spi_nor_convert_opcode(opcode, spi_nor_3to4_read,
188 				      ARRAY_SIZE(spi_nor_3to4_read));
189 }
190 
191 static void spi_nor_set_4byte_opcodes(struct spi_nor *nor,
192 				      const struct flash_info *info)
193 {
194 	nor->read_opcode = spi_nor_convert_3to4_read(nor->read_opcode);
195 }
196 
197 /* Enable/disable 4-byte addressing mode. */
198 static inline int set_4byte(struct spi_nor *nor, const struct flash_info *info,
199 			    int enable)
200 {
201 	int status;
202 	bool need_wren = false;
203 	u8 cmd;
204 
205 	switch (JEDEC_MFR(info)) {
206 	case SNOR_MFR_ST:
207 	case SNOR_MFR_MICRON:
208 		/* Some Micron need WREN command; all will accept it */
209 		need_wren = true;
210 	case SNOR_MFR_MACRONIX:
211 	case SNOR_MFR_WINBOND:
212 		if (need_wren)
213 			write_enable(nor);
214 
215 		cmd = enable ? SPINOR_OP_EN4B : SPINOR_OP_EX4B;
216 		status = spi_nor_write_reg(nor, cmd, NULL, 0);
217 		if (need_wren)
218 			write_disable(nor);
219 
220 		if (!status && !enable &&
221 		    JEDEC_MFR(info) == SNOR_MFR_WINBOND) {
222 			/*
223 			 * On Winbond W25Q256FV, leaving 4byte mode causes
224 			 * the Extended Address Register to be set to 1, so all
225 			 * 3-byte-address reads come from the second 16M.
226 			 * We must clear the register to enable normal behavior.
227 			 */
228 			write_enable(nor);
229 			nor->cmd_buf[0] = 0;
230 			spi_nor_write_reg(nor, SPINOR_OP_WREAR,
231 					  nor->cmd_buf, 1);
232 			write_disable(nor);
233 		}
234 
235 		return status;
236 	default:
237 		/* Spansion style */
238 		nor->cmd_buf[0] = enable << 7;
239 		return spi_nor_write_reg(nor, SPINOR_OP_BRWR, nor->cmd_buf, 1);
240 	}
241 }
242 
243 #if defined(CONFIG_SPI_FLASH_SPANSION) ||	\
244 	defined(CONFIG_SPI_FLASH_WINBOND) ||	\
245 	defined(CONFIG_SPI_FLASH_MACRONIX)
246 /*
247  * Read the status register, returning its value in the location
248  * Return the status register value.
249  * Returns negative if error occurred.
250  */
251 static int read_sr(struct spi_nor *nor)
252 {
253 	int ret;
254 	u8 val;
255 
256 	ret = spi_nor_read_reg(nor, SPINOR_OP_RDSR, &val, 1);
257 	if (ret < 0) {
258 		pr_debug("error %d reading SR\n", (int)ret);
259 		return ret;
260 	}
261 
262 	return val;
263 }
264 
265 /*
266  * Read the flag status register, returning its value in the location
267  * Return the status register value.
268  * Returns negative if error occurred.
269  */
270 static int read_fsr(struct spi_nor *nor)
271 {
272 	int ret;
273 	u8 val;
274 
275 	ret = spi_nor_read_reg(nor, SPINOR_OP_RDFSR, &val, 1);
276 	if (ret < 0) {
277 		pr_debug("error %d reading FSR\n", ret);
278 		return ret;
279 	}
280 
281 	return val;
282 }
283 
284 static int spi_nor_sr_ready(struct spi_nor *nor)
285 {
286 	int sr = read_sr(nor);
287 
288 	if (sr < 0)
289 		return sr;
290 
291 	return !(sr & SR_WIP);
292 }
293 
294 static int spi_nor_fsr_ready(struct spi_nor *nor)
295 {
296 	int fsr = read_fsr(nor);
297 
298 	if (fsr < 0)
299 		return fsr;
300 	return fsr & FSR_READY;
301 }
302 
303 static int spi_nor_ready(struct spi_nor *nor)
304 {
305 	int sr, fsr;
306 
307 	sr = spi_nor_sr_ready(nor);
308 	if (sr < 0)
309 		return sr;
310 	fsr = nor->flags & SNOR_F_USE_FSR ? spi_nor_fsr_ready(nor) : 1;
311 	if (fsr < 0)
312 		return fsr;
313 	return sr && fsr;
314 }
315 
316 /*
317  * Service routine to read status register until ready, or timeout occurs.
318  * Returns non-zero if error.
319  */
320 static int spi_nor_wait_till_ready_with_timeout(struct spi_nor *nor,
321 						unsigned long timeout)
322 {
323 	unsigned long timebase;
324 	int ret;
325 
326 	timebase = get_timer(0);
327 
328 	while (get_timer(timebase) < timeout) {
329 		ret = spi_nor_ready(nor);
330 		if (ret < 0)
331 			return ret;
332 		if (ret)
333 			return 0;
334 	}
335 
336 	dev_err(nor->dev, "flash operation timed out\n");
337 
338 	return -ETIMEDOUT;
339 }
340 
341 static int spi_nor_wait_till_ready(struct spi_nor *nor)
342 {
343 	return spi_nor_wait_till_ready_with_timeout(nor,
344 						    DEFAULT_READY_WAIT_JIFFIES);
345 }
346 #endif /* CONFIG_SPI_FLASH_SPANSION */
347 
348 /*
349  * Erase an address range on the nor chip.  The address range may extend
350  * one or more erase sectors.  Return an error is there is a problem erasing.
351  */
352 static int spi_nor_erase(struct mtd_info *mtd, struct erase_info *instr)
353 {
354 	return -ENOTSUPP;
355 }
356 
357 static const struct flash_info *spi_nor_read_id(struct spi_nor *nor)
358 {
359 	int			tmp;
360 	u8			id[SPI_NOR_MAX_ID_LEN];
361 	const struct flash_info	*info;
362 
363 	tmp = spi_nor_read_reg(nor, SPINOR_OP_RDID, id, SPI_NOR_MAX_ID_LEN);
364 	if (tmp < 0) {
365 		dev_dbg(nor->dev, "error %d reading JEDEC ID\n", tmp);
366 		return ERR_PTR(tmp);
367 	}
368 
369 	info = spi_nor_ids;
370 	for (; info->sector_size != 0; info++) {
371 		if (info->id_len) {
372 			if (!memcmp(info->id, id, info->id_len))
373 				return info;
374 		}
375 	}
376 	dev_dbg(nor->dev, "unrecognized JEDEC id bytes: %02x, %02x, %02x\n",
377 		id[0], id[1], id[2]);
378 	return ERR_PTR(-ENODEV);
379 }
380 
381 static int spi_nor_read(struct mtd_info *mtd, loff_t from, size_t len,
382 			size_t *retlen, u_char *buf)
383 {
384 	struct spi_nor *nor = mtd_to_spi_nor(mtd);
385 	int ret;
386 
387 	dev_dbg(nor->dev, "from 0x%08x, len %zd\n", (u32)from, len);
388 
389 	while (len) {
390 		loff_t addr = from;
391 
392 		ret = spi_nor_read_data(nor, addr, len, buf);
393 		if (ret == 0) {
394 			/* We shouldn't see 0-length reads */
395 			ret = -EIO;
396 			goto read_err;
397 		}
398 		if (ret < 0)
399 			goto read_err;
400 
401 		*retlen += ret;
402 		buf += ret;
403 		from += ret;
404 		len -= ret;
405 	}
406 	ret = 0;
407 
408 read_err:
409 	return ret;
410 }
411 
412 /*
413  * Write an address range to the nor chip.  Data must be written in
414  * FLASH_PAGESIZE chunks.  The address range may be any size provided
415  * it is within the physical boundaries.
416  */
417 static int spi_nor_write(struct mtd_info *mtd, loff_t to, size_t len,
418 			 size_t *retlen, const u_char *buf)
419 {
420 	return -ENOTSUPP;
421 }
422 
423 #ifdef CONFIG_SPI_FLASH_MACRONIX
424 /**
425  * macronix_quad_enable() - set QE bit in Status Register.
426  * @nor:	pointer to a 'struct spi_nor'
427  *
428  * Set the Quad Enable (QE) bit in the Status Register.
429  *
430  * bit 6 of the Status Register is the QE bit for Macronix like QSPI memories.
431  *
432  * Return: 0 on success, -errno otherwise.
433  */
434 static int macronix_quad_enable(struct spi_nor *nor)
435 {
436 	int ret, val;
437 
438 	val = read_sr(nor);
439 	if (val < 0)
440 		return val;
441 	if (val & SR_QUAD_EN_MX)
442 		return 0;
443 
444 	write_enable(nor);
445 
446 	write_sr(nor, val | SR_QUAD_EN_MX);
447 
448 	ret = spi_nor_wait_till_ready(nor);
449 	if (ret)
450 		return ret;
451 
452 	ret = read_sr(nor);
453 	if (!(ret > 0 && (ret & SR_QUAD_EN_MX))) {
454 		dev_err(nor->dev, "Macronix Quad bit not set\n");
455 		return -EINVAL;
456 	}
457 
458 	return 0;
459 }
460 #endif
461 
462 #if defined(CONFIG_SPI_FLASH_SPANSION) || defined(CONFIG_SPI_FLASH_WINBOND)
463 /*
464  * Write status Register and configuration register with 2 bytes
465  * The first byte will be written to the status register, while the
466  * second byte will be written to the configuration register.
467  * Return negative if error occurred.
468  */
469 static int write_sr_cr(struct spi_nor *nor, u8 *sr_cr)
470 {
471 	int ret;
472 
473 	write_enable(nor);
474 
475 	ret = spi_nor_write_reg(nor, SPINOR_OP_WRSR, sr_cr, 2);
476 	if (ret < 0) {
477 		dev_dbg(nor->dev,
478 			"error while writing configuration register\n");
479 		return -EINVAL;
480 	}
481 
482 	ret = spi_nor_wait_till_ready(nor);
483 	if (ret) {
484 		dev_dbg(nor->dev,
485 			"timeout while writing configuration register\n");
486 		return ret;
487 	}
488 
489 	return 0;
490 }
491 
492 /**
493  * spansion_read_cr_quad_enable() - set QE bit in Configuration Register.
494  * @nor:	pointer to a 'struct spi_nor'
495  *
496  * Set the Quad Enable (QE) bit in the Configuration Register.
497  * This function should be used with QSPI memories supporting the Read
498  * Configuration Register (35h) instruction.
499  *
500  * bit 1 of the Configuration Register is the QE bit for Spansion like QSPI
501  * memories.
502  *
503  * Return: 0 on success, -errno otherwise.
504  */
505 static int spansion_read_cr_quad_enable(struct spi_nor *nor)
506 {
507 	u8 sr_cr[2];
508 	int ret;
509 
510 	/* Check current Quad Enable bit value. */
511 	ret = read_cr(nor);
512 	if (ret < 0) {
513 		dev_dbg(dev, "error while reading configuration register\n");
514 		return -EINVAL;
515 	}
516 
517 	if (ret & CR_QUAD_EN_SPAN)
518 		return 0;
519 
520 	sr_cr[1] = ret | CR_QUAD_EN_SPAN;
521 
522 	/* Keep the current value of the Status Register. */
523 	ret = read_sr(nor);
524 	if (ret < 0) {
525 		dev_dbg(dev, "error while reading status register\n");
526 		return -EINVAL;
527 	}
528 	sr_cr[0] = ret;
529 
530 	ret = write_sr_cr(nor, sr_cr);
531 	if (ret)
532 		return ret;
533 
534 	/* Read back and check it. */
535 	ret = read_cr(nor);
536 	if (!(ret > 0 && (ret & CR_QUAD_EN_SPAN))) {
537 		dev_dbg(nor->dev, "Spansion Quad bit not set\n");
538 		return -EINVAL;
539 	}
540 
541 	return 0;
542 }
543 #endif /* CONFIG_SPI_FLASH_SPANSION */
544 
545 struct spi_nor_read_command {
546 	u8			num_mode_clocks;
547 	u8			num_wait_states;
548 	u8			opcode;
549 	enum spi_nor_protocol	proto;
550 };
551 
552 enum spi_nor_read_command_index {
553 	SNOR_CMD_READ,
554 	SNOR_CMD_READ_FAST,
555 
556 	/* Quad SPI */
557 	SNOR_CMD_READ_1_1_4,
558 
559 	SNOR_CMD_READ_MAX
560 };
561 
562 struct spi_nor_flash_parameter {
563 	struct spi_nor_hwcaps		hwcaps;
564 	struct spi_nor_read_command	reads[SNOR_CMD_READ_MAX];
565 };
566 
567 static void
568 spi_nor_set_read_settings(struct spi_nor_read_command *read,
569 			  u8 num_mode_clocks,
570 			  u8 num_wait_states,
571 			  u8 opcode,
572 			  enum spi_nor_protocol proto)
573 {
574 	read->num_mode_clocks = num_mode_clocks;
575 	read->num_wait_states = num_wait_states;
576 	read->opcode = opcode;
577 	read->proto = proto;
578 }
579 
580 static int spi_nor_init_params(struct spi_nor *nor,
581 			       const struct flash_info *info,
582 			       struct spi_nor_flash_parameter *params)
583 {
584 	/* (Fast) Read settings. */
585 	params->hwcaps.mask = SNOR_HWCAPS_READ;
586 	spi_nor_set_read_settings(&params->reads[SNOR_CMD_READ],
587 				  0, 0, SPINOR_OP_READ,
588 				  SNOR_PROTO_1_1_1);
589 
590 	if (!(info->flags & SPI_NOR_NO_FR)) {
591 		params->hwcaps.mask |= SNOR_HWCAPS_READ_FAST;
592 		spi_nor_set_read_settings(&params->reads[SNOR_CMD_READ_FAST],
593 					  0, 8, SPINOR_OP_READ_FAST,
594 					  SNOR_PROTO_1_1_1);
595 	}
596 
597 	if (info->flags & SPI_NOR_QUAD_READ) {
598 		params->hwcaps.mask |= SNOR_HWCAPS_READ_1_1_4;
599 		spi_nor_set_read_settings(&params->reads[SNOR_CMD_READ_1_1_4],
600 					  0, 8, SPINOR_OP_READ_1_1_4,
601 					  SNOR_PROTO_1_1_4);
602 	}
603 
604 	return 0;
605 }
606 
607 static int spi_nor_select_read(struct spi_nor *nor,
608 			       const struct spi_nor_flash_parameter *params,
609 			       u32 shared_hwcaps)
610 {
611 	int best_match = shared_hwcaps & SNOR_HWCAPS_READ_MASK;
612 	int cmd;
613 	const struct spi_nor_read_command *read;
614 
615 	if (best_match < 0)
616 		return -EINVAL;
617 
618 	if (best_match & SNOR_HWCAPS_READ_1_1_4)
619 		cmd = SNOR_CMD_READ_1_1_4;
620 	else if (best_match & SNOR_HWCAPS_READ_FAST)
621 		cmd = SNOR_CMD_READ_FAST;
622 	else
623 		cmd = SNOR_CMD_READ;
624 
625 	read = &params->reads[cmd];
626 	nor->read_opcode = read->opcode;
627 	nor->read_proto = read->proto;
628 
629 	/*
630 	 * In the spi-nor framework, we don't need to make the difference
631 	 * between mode clock cycles and wait state clock cycles.
632 	 * Indeed, the value of the mode clock cycles is used by a QSPI
633 	 * flash memory to know whether it should enter or leave its 0-4-4
634 	 * (Continuous Read / XIP) mode.
635 	 * eXecution In Place is out of the scope of the mtd sub-system.
636 	 * Hence we choose to merge both mode and wait state clock cycles
637 	 * into the so called dummy clock cycles.
638 	 */
639 	nor->read_dummy = read->num_mode_clocks + read->num_wait_states;
640 	return 0;
641 }
642 
643 static int spi_nor_setup(struct spi_nor *nor, const struct flash_info *info,
644 			 const struct spi_nor_flash_parameter *params,
645 			 const struct spi_nor_hwcaps *hwcaps)
646 {
647 	u32 shared_mask;
648 	int err;
649 
650 	/*
651 	 * Keep only the hardware capabilities supported by both the SPI
652 	 * controller and the SPI flash memory.
653 	 */
654 	shared_mask = hwcaps->mask & params->hwcaps.mask;
655 
656 	/* Select the (Fast) Read command. */
657 	err = spi_nor_select_read(nor, params, shared_mask);
658 	if (err) {
659 		dev_dbg(nor->dev,
660 			"can't select read settings supported by both the SPI controller and memory.\n");
661 		return err;
662 	}
663 
664 	/* Enable Quad I/O if needed. */
665 	if (spi_nor_get_protocol_width(nor->read_proto) == 4) {
666 		switch (JEDEC_MFR(info)) {
667 #ifdef CONFIG_SPI_FLASH_MACRONIX
668 		case SNOR_MFR_MACRONIX:
669 			err = macronix_quad_enable(nor);
670 			break;
671 #endif
672 		case SNOR_MFR_ST:
673 		case SNOR_MFR_MICRON:
674 			break;
675 
676 		default:
677 #if defined(CONFIG_SPI_FLASH_SPANSION) || defined(CONFIG_SPI_FLASH_WINBOND)
678 			/* Kept only for backward compatibility purpose. */
679 			err = spansion_read_cr_quad_enable(nor);
680 #endif
681 			break;
682 		}
683 	}
684 	if (err) {
685 		dev_dbg(nor->dev, "quad mode not supported\n");
686 		return err;
687 	}
688 
689 	return 0;
690 }
691 
692 static int spi_nor_init(struct spi_nor *nor)
693 {
694 	if (nor->addr_width == 4 &&
695 	    (JEDEC_MFR(nor->info) != SNOR_MFR_SPANSION) &&
696 	    !(nor->info->flags & SPI_NOR_4B_OPCODES)) {
697 		/*
698 		 * If the RESET# pin isn't hooked up properly, or the system
699 		 * otherwise doesn't perform a reset command in the boot
700 		 * sequence, it's impossible to 100% protect against unexpected
701 		 * reboots (e.g., crashes). Warn the user (or hopefully, system
702 		 * designer) that this is bad.
703 		 */
704 		if (nor->flags & SNOR_F_BROKEN_RESET)
705 			printf("enabling reset hack; may not recover from unexpected reboots\n");
706 		set_4byte(nor, nor->info, 1);
707 	}
708 
709 	return 0;
710 }
711 
712 int spi_nor_scan(struct spi_nor *nor)
713 {
714 	struct spi_nor_flash_parameter params;
715 	const struct flash_info *info = NULL;
716 	struct mtd_info *mtd = &nor->mtd;
717 	struct spi_nor_hwcaps hwcaps = {
718 		.mask = SNOR_HWCAPS_READ |
719 			SNOR_HWCAPS_READ_FAST
720 	};
721 	struct spi_slave *spi = nor->spi;
722 	int ret;
723 
724 	/* Reset SPI protocol for all commands. */
725 	nor->reg_proto = SNOR_PROTO_1_1_1;
726 	nor->read_proto = SNOR_PROTO_1_1_1;
727 	nor->write_proto = SNOR_PROTO_1_1_1;
728 
729 	if (spi->mode & SPI_RX_QUAD)
730 		hwcaps.mask |= SNOR_HWCAPS_READ_1_1_4;
731 
732 	info = spi_nor_read_id(nor);
733 	if (IS_ERR_OR_NULL(info))
734 		return -ENOENT;
735 	/* Parse the Serial Flash Discoverable Parameters table. */
736 	ret = spi_nor_init_params(nor, info, &params);
737 	if (ret)
738 		return ret;
739 
740 	mtd->name = "spi-flash";
741 	mtd->priv = nor;
742 	mtd->type = MTD_NORFLASH;
743 	mtd->writesize = 1;
744 	mtd->flags = MTD_CAP_NORFLASH;
745 	mtd->size = info->sector_size * info->n_sectors;
746 	mtd->_erase = spi_nor_erase;
747 	mtd->_read = spi_nor_read;
748 	mtd->_write = spi_nor_write;
749 
750 	nor->size = mtd->size;
751 
752 	if (info->flags & USE_FSR)
753 		nor->flags |= SNOR_F_USE_FSR;
754 	if (info->flags & USE_CLSR)
755 		nor->flags |= SNOR_F_USE_CLSR;
756 
757 	if (info->flags & SPI_NOR_NO_FR)
758 		params.hwcaps.mask &= ~SNOR_HWCAPS_READ_FAST;
759 
760 	/*
761 	 * Configure the SPI memory:
762 	 * - select op codes for (Fast) Read, Page Program and Sector Erase.
763 	 * - set the number of dummy cycles (mode cycles + wait states).
764 	 * - set the SPI protocols for register and memory accesses.
765 	 * - set the Quad Enable bit if needed (required by SPI x-y-4 protos).
766 	 */
767 	ret = spi_nor_setup(nor, info, &params, &hwcaps);
768 	if (ret)
769 		return ret;
770 
771 	if (nor->addr_width) {
772 		/* already configured from SFDP */
773 	} else if (info->addr_width) {
774 		nor->addr_width = info->addr_width;
775 	} else if (mtd->size > 0x1000000) {
776 		/* enable 4-byte addressing if the device exceeds 16MiB */
777 		nor->addr_width = 4;
778 		if (JEDEC_MFR(info) == SNOR_MFR_SPANSION ||
779 		    info->flags & SPI_NOR_4B_OPCODES)
780 			spi_nor_set_4byte_opcodes(nor, info);
781 	} else {
782 		nor->addr_width = 3;
783 	}
784 
785 	if (nor->addr_width > SPI_NOR_MAX_ADDR_WIDTH) {
786 		dev_dbg(dev, "address width is too large: %u\n",
787 			nor->addr_width);
788 		return -EINVAL;
789 	}
790 
791 	/* Send all the required SPI flash commands to initialize device */
792 	nor->info = info;
793 	ret = spi_nor_init(nor);
794 	if (ret)
795 		return ret;
796 
797 	return 0;
798 }
799 
800 /* U-Boot specific functions, need to extend MTD to support these */
801 int spi_flash_cmd_get_sw_write_prot(struct spi_nor *nor)
802 {
803 	return -ENOTSUPP;
804 }
805