xref: /linux/drivers/mtd/devices/mtd_dataflash.c (revision 249ebf3f65f8530beb2cbfb91bff1d83ba88d23c)
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * Atmel AT45xxx DataFlash MTD driver for lightweight SPI framework
4  *
5  * Largely derived from at91_dataflash.c:
6  *  Copyright (C) 2003-2005 SAN People (Pty) Ltd
7 */
8 #include <linux/module.h>
9 #include <linux/slab.h>
10 #include <linux/delay.h>
11 #include <linux/device.h>
12 #include <linux/mutex.h>
13 #include <linux/err.h>
14 #include <linux/math64.h>
15 #include <linux/of.h>
16 
17 #include <linux/spi/spi.h>
18 #include <linux/spi/flash.h>
19 
20 #include <linux/mtd/mtd.h>
21 #include <linux/mtd/partitions.h>
22 
23 /*
24  * DataFlash is a kind of SPI flash.  Most AT45 chips have two buffers in
25  * each chip, which may be used for double buffered I/O; but this driver
26  * doesn't (yet) use these for any kind of i/o overlap or prefetching.
27  *
28  * Sometimes DataFlash is packaged in MMC-format cards, although the
29  * MMC stack can't (yet?) distinguish between MMC and DataFlash
30  * protocols during enumeration.
31  */
32 
33 /* reads can bypass the buffers */
34 #define OP_READ_CONTINUOUS	0xE8
35 #define OP_READ_PAGE		0xD2
36 
37 /* group B requests can run even while status reports "busy" */
38 #define OP_READ_STATUS		0xD7	/* group B */
39 
40 /* move data between host and buffer */
41 #define OP_READ_BUFFER1		0xD4	/* group B */
42 #define OP_READ_BUFFER2		0xD6	/* group B */
43 #define OP_WRITE_BUFFER1	0x84	/* group B */
44 #define OP_WRITE_BUFFER2	0x87	/* group B */
45 
46 /* erasing flash */
47 #define OP_ERASE_PAGE		0x81
48 #define OP_ERASE_BLOCK		0x50
49 
50 /* move data between buffer and flash */
51 #define OP_TRANSFER_BUF1	0x53
52 #define OP_TRANSFER_BUF2	0x55
53 #define OP_MREAD_BUFFER1	0xD4
54 #define OP_MREAD_BUFFER2	0xD6
55 #define OP_MWERASE_BUFFER1	0x83
56 #define OP_MWERASE_BUFFER2	0x86
57 #define OP_MWRITE_BUFFER1	0x88	/* sector must be pre-erased */
58 #define OP_MWRITE_BUFFER2	0x89	/* sector must be pre-erased */
59 
60 /* write to buffer, then write-erase to flash */
61 #define OP_PROGRAM_VIA_BUF1	0x82
62 #define OP_PROGRAM_VIA_BUF2	0x85
63 
64 /* compare buffer to flash */
65 #define OP_COMPARE_BUF1		0x60
66 #define OP_COMPARE_BUF2		0x61
67 
68 /* read flash to buffer, then write-erase to flash */
69 #define OP_REWRITE_VIA_BUF1	0x58
70 #define OP_REWRITE_VIA_BUF2	0x59
71 
72 /* newer chips report JEDEC manufacturer and device IDs; chip
73  * serial number and OTP bits; and per-sector writeprotect.
74  */
75 #define OP_READ_ID		0x9F
76 #define OP_READ_SECURITY	0x77
77 #define OP_WRITE_SECURITY_REVC	0x9A
78 #define OP_WRITE_SECURITY	0x9B	/* revision D */
79 
80 #define CFI_MFR_ATMEL		0x1F
81 
82 #define DATAFLASH_SHIFT_EXTID	24
83 #define DATAFLASH_SHIFT_ID	40
84 
85 struct dataflash {
86 	u8			command[4];
87 	char			name[24];
88 
89 	unsigned short		page_offset;	/* offset in flash address */
90 	unsigned int		page_size;	/* of bytes per page */
91 
92 	struct mutex		lock;
93 	struct spi_device	*spi;
94 
95 	struct mtd_info		mtd;
96 };
97 
98 #ifdef CONFIG_OF
99 static const struct of_device_id dataflash_dt_ids[] = {
100 	{ .compatible = "atmel,at45", },
101 	{ .compatible = "atmel,dataflash", },
102 	{ /* sentinel */ }
103 };
104 MODULE_DEVICE_TABLE(of, dataflash_dt_ids);
105 #endif
106 
107 static const struct spi_device_id dataflash_spi_ids[] = {
108 	{ .name = "at45", },
109 	{ .name = "dataflash", },
110 	{ /* sentinel */ }
111 };
112 MODULE_DEVICE_TABLE(spi, dataflash_spi_ids);
113 
114 /* ......................................................................... */
115 
116 /*
117  * Return the status of the DataFlash device.
118  */
119 static inline int dataflash_status(struct spi_device *spi)
120 {
121 	/* NOTE:  at45db321c over 25 MHz wants to write
122 	 * a dummy byte after the opcode...
123 	 */
124 	return spi_w8r8(spi, OP_READ_STATUS);
125 }
126 
127 /*
128  * Poll the DataFlash device until it is READY.
129  * This usually takes 5-20 msec or so; more for sector erase.
130  */
131 static int dataflash_waitready(struct spi_device *spi)
132 {
133 	int	status;
134 
135 	for (;;) {
136 		status = dataflash_status(spi);
137 		if (status < 0) {
138 			dev_dbg(&spi->dev, "status %d?\n", status);
139 			status = 0;
140 		}
141 
142 		if (status & (1 << 7))	/* RDY/nBSY */
143 			return status;
144 
145 		usleep_range(3000, 4000);
146 	}
147 }
148 
149 /* ......................................................................... */
150 
151 /*
152  * Erase pages of flash.
153  */
154 static int dataflash_erase(struct mtd_info *mtd, struct erase_info *instr)
155 {
156 	struct dataflash	*priv = mtd->priv;
157 	struct spi_device	*spi = priv->spi;
158 	struct spi_transfer	x = { };
159 	struct spi_message	msg;
160 	unsigned		blocksize = priv->page_size << 3;
161 	u8			*command;
162 	u32			rem;
163 
164 	dev_dbg(&spi->dev, "erase addr=0x%llx len 0x%llx\n",
165 		(long long)instr->addr, (long long)instr->len);
166 
167 	div_u64_rem(instr->len, priv->page_size, &rem);
168 	if (rem)
169 		return -EINVAL;
170 	div_u64_rem(instr->addr, priv->page_size, &rem);
171 	if (rem)
172 		return -EINVAL;
173 
174 	spi_message_init(&msg);
175 
176 	x.tx_buf = command = priv->command;
177 	x.len = 4;
178 	spi_message_add_tail(&x, &msg);
179 
180 	mutex_lock(&priv->lock);
181 	while (instr->len > 0) {
182 		unsigned int	pageaddr;
183 		int		status;
184 		int		do_block;
185 
186 		/* Calculate flash page address; use block erase (for speed) if
187 		 * we're at a block boundary and need to erase the whole block.
188 		 */
189 		pageaddr = div_u64(instr->addr, priv->page_size);
190 		do_block = (pageaddr & 0x7) == 0 && instr->len >= blocksize;
191 		pageaddr = pageaddr << priv->page_offset;
192 
193 		command[0] = do_block ? OP_ERASE_BLOCK : OP_ERASE_PAGE;
194 		command[1] = (u8)(pageaddr >> 16);
195 		command[2] = (u8)(pageaddr >> 8);
196 		command[3] = 0;
197 
198 		dev_dbg(&spi->dev, "ERASE %s: (%x) %x %x %x [%i]\n",
199 			do_block ? "block" : "page",
200 			command[0], command[1], command[2], command[3],
201 			pageaddr);
202 
203 		status = spi_sync(spi, &msg);
204 		(void) dataflash_waitready(spi);
205 
206 		if (status < 0) {
207 			dev_err(&spi->dev, "erase %x, err %d\n",
208 				pageaddr, status);
209 			/* REVISIT:  can retry instr->retries times; or
210 			 * giveup and instr->fail_addr = instr->addr;
211 			 */
212 			continue;
213 		}
214 
215 		if (do_block) {
216 			instr->addr += blocksize;
217 			instr->len -= blocksize;
218 		} else {
219 			instr->addr += priv->page_size;
220 			instr->len -= priv->page_size;
221 		}
222 	}
223 	mutex_unlock(&priv->lock);
224 
225 	return 0;
226 }
227 
228 /*
229  * Read from the DataFlash device.
230  *   from   : Start offset in flash device
231  *   len    : Amount to read
232  *   retlen : About of data actually read
233  *   buf    : Buffer containing the data
234  */
235 static int dataflash_read(struct mtd_info *mtd, loff_t from, size_t len,
236 			       size_t *retlen, u_char *buf)
237 {
238 	struct dataflash	*priv = mtd->priv;
239 	struct spi_transfer	x[2] = { };
240 	struct spi_message	msg;
241 	unsigned int		addr;
242 	u8			*command;
243 	int			status;
244 
245 	dev_dbg(&priv->spi->dev, "read 0x%x..0x%x\n",
246 		  (unsigned int)from, (unsigned int)(from + len));
247 
248 	/* Calculate flash page/byte address */
249 	addr = (((unsigned)from / priv->page_size) << priv->page_offset)
250 		+ ((unsigned)from % priv->page_size);
251 
252 	command = priv->command;
253 
254 	dev_dbg(&priv->spi->dev, "READ: (%x) %x %x %x\n",
255 		command[0], command[1], command[2], command[3]);
256 
257 	spi_message_init(&msg);
258 
259 	x[0].tx_buf = command;
260 	x[0].len = 8;
261 	spi_message_add_tail(&x[0], &msg);
262 
263 	x[1].rx_buf = buf;
264 	x[1].len = len;
265 	spi_message_add_tail(&x[1], &msg);
266 
267 	mutex_lock(&priv->lock);
268 
269 	/* Continuous read, max clock = f(car) which may be less than
270 	 * the peak rate available.  Some chips support commands with
271 	 * fewer "don't care" bytes.  Both buffers stay unchanged.
272 	 */
273 	command[0] = OP_READ_CONTINUOUS;
274 	command[1] = (u8)(addr >> 16);
275 	command[2] = (u8)(addr >> 8);
276 	command[3] = (u8)(addr >> 0);
277 	/* plus 4 "don't care" bytes */
278 
279 	status = spi_sync(priv->spi, &msg);
280 	mutex_unlock(&priv->lock);
281 
282 	if (status >= 0) {
283 		*retlen = msg.actual_length - 8;
284 		status = 0;
285 	} else
286 		dev_dbg(&priv->spi->dev, "read %x..%x --> %d\n",
287 			(unsigned)from, (unsigned)(from + len),
288 			status);
289 	return status;
290 }
291 
292 /*
293  * Write to the DataFlash device.
294  *   to     : Start offset in flash device
295  *   len    : Amount to write
296  *   retlen : Amount of data actually written
297  *   buf    : Buffer containing the data
298  */
299 static int dataflash_write(struct mtd_info *mtd, loff_t to, size_t len,
300 				size_t * retlen, const u_char * buf)
301 {
302 	struct dataflash	*priv = mtd->priv;
303 	struct spi_device	*spi = priv->spi;
304 	struct spi_transfer	x[2] = { };
305 	struct spi_message	msg;
306 	unsigned int		pageaddr, addr, offset, writelen;
307 	size_t			remaining = len;
308 	u_char			*writebuf = (u_char *) buf;
309 	int			status = -EINVAL;
310 	u8			*command;
311 
312 	dev_dbg(&spi->dev, "write 0x%x..0x%x\n",
313 		(unsigned int)to, (unsigned int)(to + len));
314 
315 	spi_message_init(&msg);
316 
317 	x[0].tx_buf = command = priv->command;
318 	x[0].len = 4;
319 	spi_message_add_tail(&x[0], &msg);
320 
321 	pageaddr = ((unsigned)to / priv->page_size);
322 	offset = ((unsigned)to % priv->page_size);
323 	if (offset + len > priv->page_size)
324 		writelen = priv->page_size - offset;
325 	else
326 		writelen = len;
327 
328 	mutex_lock(&priv->lock);
329 	while (remaining > 0) {
330 		dev_dbg(&spi->dev, "write @ %i:%i len=%i\n",
331 			pageaddr, offset, writelen);
332 
333 		/* REVISIT:
334 		 * (a) each page in a sector must be rewritten at least
335 		 *     once every 10K sibling erase/program operations.
336 		 * (b) for pages that are already erased, we could
337 		 *     use WRITE+MWRITE not PROGRAM for ~30% speedup.
338 		 * (c) WRITE to buffer could be done while waiting for
339 		 *     a previous MWRITE/MWERASE to complete ...
340 		 * (d) error handling here seems to be mostly missing.
341 		 *
342 		 * Two persistent bits per page, plus a per-sector counter,
343 		 * could support (a) and (b) ... we might consider using
344 		 * the second half of sector zero, which is just one block,
345 		 * to track that state.  (On AT91, that sector should also
346 		 * support boot-from-DataFlash.)
347 		 */
348 
349 		addr = pageaddr << priv->page_offset;
350 
351 		/* (1) Maybe transfer partial page to Buffer1 */
352 		if (writelen != priv->page_size) {
353 			command[0] = OP_TRANSFER_BUF1;
354 			command[1] = (addr & 0x00FF0000) >> 16;
355 			command[2] = (addr & 0x0000FF00) >> 8;
356 			command[3] = 0;
357 
358 			dev_dbg(&spi->dev, "TRANSFER: (%x) %x %x %x\n",
359 				command[0], command[1], command[2], command[3]);
360 
361 			status = spi_sync(spi, &msg);
362 			if (status < 0)
363 				dev_dbg(&spi->dev, "xfer %u -> %d\n",
364 					addr, status);
365 
366 			(void) dataflash_waitready(priv->spi);
367 		}
368 
369 		/* (2) Program full page via Buffer1 */
370 		addr += offset;
371 		command[0] = OP_PROGRAM_VIA_BUF1;
372 		command[1] = (addr & 0x00FF0000) >> 16;
373 		command[2] = (addr & 0x0000FF00) >> 8;
374 		command[3] = (addr & 0x000000FF);
375 
376 		dev_dbg(&spi->dev, "PROGRAM: (%x) %x %x %x\n",
377 			command[0], command[1], command[2], command[3]);
378 
379 		x[1].tx_buf = writebuf;
380 		x[1].len = writelen;
381 		spi_message_add_tail(x + 1, &msg);
382 		status = spi_sync(spi, &msg);
383 		spi_transfer_del(x + 1);
384 		if (status < 0)
385 			dev_dbg(&spi->dev, "pgm %u/%u -> %d\n",
386 				addr, writelen, status);
387 
388 		(void) dataflash_waitready(priv->spi);
389 
390 
391 #ifdef CONFIG_MTD_DATAFLASH_WRITE_VERIFY
392 
393 		/* (3) Compare to Buffer1 */
394 		addr = pageaddr << priv->page_offset;
395 		command[0] = OP_COMPARE_BUF1;
396 		command[1] = (addr & 0x00FF0000) >> 16;
397 		command[2] = (addr & 0x0000FF00) >> 8;
398 		command[3] = 0;
399 
400 		dev_dbg(&spi->dev, "COMPARE: (%x) %x %x %x\n",
401 			command[0], command[1], command[2], command[3]);
402 
403 		status = spi_sync(spi, &msg);
404 		if (status < 0)
405 			dev_dbg(&spi->dev, "compare %u -> %d\n",
406 				addr, status);
407 
408 		status = dataflash_waitready(priv->spi);
409 
410 		/* Check result of the compare operation */
411 		if (status & (1 << 6)) {
412 			dev_err(&spi->dev, "compare page %u, err %d\n",
413 				pageaddr, status);
414 			remaining = 0;
415 			status = -EIO;
416 			break;
417 		} else
418 			status = 0;
419 
420 #endif	/* CONFIG_MTD_DATAFLASH_WRITE_VERIFY */
421 
422 		remaining = remaining - writelen;
423 		pageaddr++;
424 		offset = 0;
425 		writebuf += writelen;
426 		*retlen += writelen;
427 
428 		if (remaining > priv->page_size)
429 			writelen = priv->page_size;
430 		else
431 			writelen = remaining;
432 	}
433 	mutex_unlock(&priv->lock);
434 
435 	return status;
436 }
437 
438 /* ......................................................................... */
439 
440 #ifdef CONFIG_MTD_DATAFLASH_OTP
441 
442 static int dataflash_get_otp_info(struct mtd_info *mtd, size_t len,
443 				  size_t *retlen, struct otp_info *info)
444 {
445 	/* Report both blocks as identical:  bytes 0..64, locked.
446 	 * Unless the user block changed from all-ones, we can't
447 	 * tell whether it's still writable; so we assume it isn't.
448 	 */
449 	info->start = 0;
450 	info->length = 64;
451 	info->locked = 1;
452 	*retlen = sizeof(*info);
453 	return 0;
454 }
455 
456 static ssize_t otp_read(struct spi_device *spi, unsigned base,
457 		u8 *buf, loff_t off, size_t len)
458 {
459 	struct spi_message	m;
460 	size_t			l;
461 	u8			*scratch;
462 	struct spi_transfer	t;
463 	int			status;
464 
465 	if (off > 64)
466 		return -EINVAL;
467 
468 	if ((off + len) > 64)
469 		len = 64 - off;
470 
471 	spi_message_init(&m);
472 
473 	l = 4 + base + off + len;
474 	scratch = kzalloc(l, GFP_KERNEL);
475 	if (!scratch)
476 		return -ENOMEM;
477 
478 	/* OUT: OP_READ_SECURITY, 3 don't-care bytes, zeroes
479 	 * IN:  ignore 4 bytes, data bytes 0..N (max 127)
480 	 */
481 	scratch[0] = OP_READ_SECURITY;
482 
483 	memset(&t, 0, sizeof t);
484 	t.tx_buf = scratch;
485 	t.rx_buf = scratch;
486 	t.len = l;
487 	spi_message_add_tail(&t, &m);
488 
489 	dataflash_waitready(spi);
490 
491 	status = spi_sync(spi, &m);
492 	if (status >= 0) {
493 		memcpy(buf, scratch + 4 + base + off, len);
494 		status = len;
495 	}
496 
497 	kfree(scratch);
498 	return status;
499 }
500 
501 static int dataflash_read_fact_otp(struct mtd_info *mtd,
502 		loff_t from, size_t len, size_t *retlen, u_char *buf)
503 {
504 	struct dataflash	*priv = mtd->priv;
505 	int			status;
506 
507 	/* 64 bytes, from 0..63 ... start at 64 on-chip */
508 	mutex_lock(&priv->lock);
509 	status = otp_read(priv->spi, 64, buf, from, len);
510 	mutex_unlock(&priv->lock);
511 
512 	if (status < 0)
513 		return status;
514 	*retlen = status;
515 	return 0;
516 }
517 
518 static int dataflash_read_user_otp(struct mtd_info *mtd,
519 		loff_t from, size_t len, size_t *retlen, u_char *buf)
520 {
521 	struct dataflash	*priv = mtd->priv;
522 	int			status;
523 
524 	/* 64 bytes, from 0..63 ... start at 0 on-chip */
525 	mutex_lock(&priv->lock);
526 	status = otp_read(priv->spi, 0, buf, from, len);
527 	mutex_unlock(&priv->lock);
528 
529 	if (status < 0)
530 		return status;
531 	*retlen = status;
532 	return 0;
533 }
534 
535 static int dataflash_write_user_otp(struct mtd_info *mtd,
536 		loff_t from, size_t len, size_t *retlen, const u_char *buf)
537 {
538 	struct spi_message	m;
539 	const size_t		l = 4 + 64;
540 	u8			*scratch;
541 	struct spi_transfer	t;
542 	struct dataflash	*priv = mtd->priv;
543 	int			status;
544 
545 	if (from >= 64) {
546 		/*
547 		 * Attempting to write beyond the end of OTP memory,
548 		 * no data can be written.
549 		 */
550 		*retlen = 0;
551 		return 0;
552 	}
553 
554 	/* Truncate the write to fit into OTP memory. */
555 	if ((from + len) > 64)
556 		len = 64 - from;
557 
558 	/* OUT: OP_WRITE_SECURITY, 3 zeroes, 64 data-or-zero bytes
559 	 * IN:  ignore all
560 	 */
561 	scratch = kzalloc(l, GFP_KERNEL);
562 	if (!scratch)
563 		return -ENOMEM;
564 	scratch[0] = OP_WRITE_SECURITY;
565 	memcpy(scratch + 4 + from, buf, len);
566 
567 	spi_message_init(&m);
568 
569 	memset(&t, 0, sizeof t);
570 	t.tx_buf = scratch;
571 	t.len = l;
572 	spi_message_add_tail(&t, &m);
573 
574 	/* Write the OTP bits, if they've not yet been written.
575 	 * This modifies SRAM buffer1.
576 	 */
577 	mutex_lock(&priv->lock);
578 	dataflash_waitready(priv->spi);
579 	status = spi_sync(priv->spi, &m);
580 	mutex_unlock(&priv->lock);
581 
582 	kfree(scratch);
583 
584 	if (status >= 0) {
585 		status = 0;
586 		*retlen = len;
587 	}
588 	return status;
589 }
590 
591 static char *otp_setup(struct mtd_info *device, char revision)
592 {
593 	device->_get_fact_prot_info = dataflash_get_otp_info;
594 	device->_read_fact_prot_reg = dataflash_read_fact_otp;
595 	device->_get_user_prot_info = dataflash_get_otp_info;
596 	device->_read_user_prot_reg = dataflash_read_user_otp;
597 
598 	/* rev c parts (at45db321c and at45db1281 only!) use a
599 	 * different write procedure; not (yet?) implemented.
600 	 */
601 	if (revision > 'c')
602 		device->_write_user_prot_reg = dataflash_write_user_otp;
603 
604 	return ", OTP";
605 }
606 
607 #else
608 
609 static char *otp_setup(struct mtd_info *device, char revision)
610 {
611 	return " (OTP)";
612 }
613 
614 #endif
615 
616 /* ......................................................................... */
617 
618 /*
619  * Register DataFlash device with MTD subsystem.
620  */
621 static int add_dataflash_otp(struct spi_device *spi, char *name, int nr_pages,
622 			     int pagesize, int pageoffset, char revision)
623 {
624 	struct dataflash		*priv;
625 	struct mtd_info			*device;
626 	struct flash_platform_data	*pdata = dev_get_platdata(&spi->dev);
627 	char				*otp_tag = "";
628 	int				err = 0;
629 
630 	priv = kzalloc(sizeof *priv, GFP_KERNEL);
631 	if (!priv)
632 		return -ENOMEM;
633 
634 	mutex_init(&priv->lock);
635 	priv->spi = spi;
636 	priv->page_size = pagesize;
637 	priv->page_offset = pageoffset;
638 
639 	/* name must be usable with cmdlinepart */
640 	sprintf(priv->name, "spi%d.%d-%s",
641 			spi->controller->bus_num, spi_get_chipselect(spi, 0),
642 			name);
643 
644 	device = &priv->mtd;
645 	device->name = (pdata && pdata->name) ? pdata->name : priv->name;
646 	device->size = nr_pages * pagesize;
647 	device->erasesize = pagesize;
648 	device->writesize = pagesize;
649 	device->type = MTD_DATAFLASH;
650 	device->flags = MTD_WRITEABLE;
651 	device->_erase = dataflash_erase;
652 	device->_read = dataflash_read;
653 	device->_write = dataflash_write;
654 	device->priv = priv;
655 
656 	device->dev.parent = &spi->dev;
657 	mtd_set_of_node(device, spi->dev.of_node);
658 
659 	if (revision >= 'c')
660 		otp_tag = otp_setup(device, revision);
661 
662 	dev_info(&spi->dev, "%s (%lld KBytes) pagesize %d bytes%s\n",
663 			name, (long long)((device->size + 1023) >> 10),
664 			pagesize, otp_tag);
665 	spi_set_drvdata(spi, priv);
666 
667 	err = mtd_device_register(device,
668 			pdata ? pdata->parts : NULL,
669 			pdata ? pdata->nr_parts : 0);
670 
671 	if (!err)
672 		return 0;
673 
674 	kfree(priv);
675 	return err;
676 }
677 
678 static inline int add_dataflash(struct spi_device *spi, char *name,
679 				int nr_pages, int pagesize, int pageoffset)
680 {
681 	return add_dataflash_otp(spi, name, nr_pages, pagesize,
682 			pageoffset, 0);
683 }
684 
685 struct flash_info {
686 	char		*name;
687 
688 	/* JEDEC id has a high byte of zero plus three data bytes:
689 	 * the manufacturer id, then a two byte device id.
690 	 */
691 	u64		jedec_id;
692 
693 	/* The size listed here is what works with OP_ERASE_PAGE. */
694 	unsigned	nr_pages;
695 	u16		pagesize;
696 	u16		pageoffset;
697 
698 	u16		flags;
699 #define SUP_EXTID	0x0004		/* supports extended ID data */
700 #define SUP_POW2PS	0x0002		/* supports 2^N byte pages */
701 #define IS_POW2PS	0x0001		/* uses 2^N byte pages */
702 };
703 
704 static struct flash_info dataflash_data[] = {
705 
706 	/*
707 	 * NOTE:  chips with SUP_POW2PS (rev D and up) need two entries,
708 	 * one with IS_POW2PS and the other without.  The entry with the
709 	 * non-2^N byte page size can't name exact chip revisions without
710 	 * losing backwards compatibility for cmdlinepart.
711 	 *
712 	 * These newer chips also support 128-byte security registers (with
713 	 * 64 bytes one-time-programmable) and software write-protection.
714 	 */
715 	{ "AT45DB011B",  0x1f2200, 512, 264, 9, SUP_POW2PS},
716 	{ "at45db011d",  0x1f2200, 512, 256, 8, SUP_POW2PS | IS_POW2PS},
717 
718 	{ "AT45DB021B",  0x1f2300, 1024, 264, 9, SUP_POW2PS},
719 	{ "at45db021d",  0x1f2300, 1024, 256, 8, SUP_POW2PS | IS_POW2PS},
720 
721 	{ "AT45DB041x",  0x1f2400, 2048, 264, 9, SUP_POW2PS},
722 	{ "at45db041d",  0x1f2400, 2048, 256, 8, SUP_POW2PS | IS_POW2PS},
723 
724 	{ "AT45DB081B",  0x1f2500, 4096, 264, 9, SUP_POW2PS},
725 	{ "at45db081d",  0x1f2500, 4096, 256, 8, SUP_POW2PS | IS_POW2PS},
726 
727 	{ "AT45DB161x",  0x1f2600, 4096, 528, 10, SUP_POW2PS},
728 	{ "at45db161d",  0x1f2600, 4096, 512, 9, SUP_POW2PS | IS_POW2PS},
729 
730 	{ "AT45DB321x",  0x1f2700, 8192, 528, 10, 0},		/* rev C */
731 
732 	{ "AT45DB321x",  0x1f2701, 8192, 528, 10, SUP_POW2PS},
733 	{ "at45db321d",  0x1f2701, 8192, 512, 9, SUP_POW2PS | IS_POW2PS},
734 
735 	{ "AT45DB642x",  0x1f2800, 8192, 1056, 11, SUP_POW2PS},
736 	{ "at45db642d",  0x1f2800, 8192, 1024, 10, SUP_POW2PS | IS_POW2PS},
737 
738 	{ "AT45DB641E",  0x1f28000100ULL, 32768, 264, 9, SUP_EXTID | SUP_POW2PS},
739 	{ "at45db641e",  0x1f28000100ULL, 32768, 256, 8, SUP_EXTID | SUP_POW2PS | IS_POW2PS},
740 };
741 
742 static struct flash_info *jedec_lookup(struct spi_device *spi,
743 				       u64 jedec, bool use_extid)
744 {
745 	struct flash_info *info;
746 	int status;
747 
748 	for (info = dataflash_data;
749 	     info < dataflash_data + ARRAY_SIZE(dataflash_data);
750 	     info++) {
751 		if (use_extid && !(info->flags & SUP_EXTID))
752 			continue;
753 
754 		if (info->jedec_id == jedec) {
755 			dev_dbg(&spi->dev, "OTP, sector protect%s\n",
756 				(info->flags & SUP_POW2PS) ?
757 				", binary pagesize" : "");
758 			if (info->flags & SUP_POW2PS) {
759 				status = dataflash_status(spi);
760 				if (status < 0) {
761 					dev_dbg(&spi->dev, "status error %d\n",
762 						status);
763 					return ERR_PTR(status);
764 				}
765 				if (status & 0x1) {
766 					if (info->flags & IS_POW2PS)
767 						return info;
768 				} else {
769 					if (!(info->flags & IS_POW2PS))
770 						return info;
771 				}
772 			} else
773 				return info;
774 		}
775 	}
776 
777 	return ERR_PTR(-ENODEV);
778 }
779 
780 static struct flash_info *jedec_probe(struct spi_device *spi)
781 {
782 	int ret;
783 	u8 code = OP_READ_ID;
784 	u64 jedec;
785 	u8 id[sizeof(jedec)] = {0};
786 	const unsigned int id_size = 5;
787 	struct flash_info *info;
788 
789 	/*
790 	 * JEDEC also defines an optional "extended device information"
791 	 * string for after vendor-specific data, after the three bytes
792 	 * we use here.  Supporting some chips might require using it.
793 	 *
794 	 * If the vendor ID isn't Atmel's (0x1f), assume this call failed.
795 	 * That's not an error; only rev C and newer chips handle it, and
796 	 * only Atmel sells these chips.
797 	 */
798 	ret = spi_write_then_read(spi, &code, 1, id, id_size);
799 	if (ret < 0) {
800 		dev_dbg(&spi->dev, "error %d reading JEDEC ID\n", ret);
801 		return ERR_PTR(ret);
802 	}
803 
804 	if (id[0] != CFI_MFR_ATMEL)
805 		return NULL;
806 
807 	jedec = be64_to_cpup((__be64 *)id);
808 
809 	/*
810 	 * First, try to match device using extended device
811 	 * information
812 	 */
813 	info = jedec_lookup(spi, jedec >> DATAFLASH_SHIFT_EXTID, true);
814 	if (!IS_ERR(info))
815 		return info;
816 	/*
817 	 * If that fails, make another pass using regular ID
818 	 * information
819 	 */
820 	info = jedec_lookup(spi, jedec >> DATAFLASH_SHIFT_ID, false);
821 	if (!IS_ERR(info))
822 		return info;
823 	/*
824 	 * Treat other chips as errors ... we won't know the right page
825 	 * size (it might be binary) even when we can tell which density
826 	 * class is involved (legacy chip id scheme).
827 	 */
828 	dev_warn(&spi->dev, "JEDEC id %016llx not handled\n", jedec);
829 	return ERR_PTR(-ENODEV);
830 }
831 
832 /*
833  * Detect and initialize DataFlash device, using JEDEC IDs on newer chips
834  * or else the ID code embedded in the status bits:
835  *
836  *   Device      Density         ID code          #Pages PageSize  Offset
837  *   AT45DB011B  1Mbit   (128K)  xx0011xx (0x0c)    512    264      9
838  *   AT45DB021B  2Mbit   (256K)  xx0101xx (0x14)   1024    264      9
839  *   AT45DB041B  4Mbit   (512K)  xx0111xx (0x1c)   2048    264      9
840  *   AT45DB081B  8Mbit   (1M)    xx1001xx (0x24)   4096    264      9
841  *   AT45DB0161B 16Mbit  (2M)    xx1011xx (0x2c)   4096    528     10
842  *   AT45DB0321B 32Mbit  (4M)    xx1101xx (0x34)   8192    528     10
843  *   AT45DB0642  64Mbit  (8M)    xx111xxx (0x3c)   8192   1056     11
844  *   AT45DB1282  128Mbit (16M)   xx0100xx (0x10)  16384   1056     11
845  */
846 static int dataflash_probe(struct spi_device *spi)
847 {
848 	int status;
849 	struct flash_info	*info;
850 
851 	/*
852 	 * Try to detect dataflash by JEDEC ID.
853 	 * If it succeeds we know we have either a C or D part.
854 	 * D will support power of 2 pagesize option.
855 	 * Both support the security register, though with different
856 	 * write procedures.
857 	 */
858 	info = jedec_probe(spi);
859 	if (IS_ERR(info))
860 		return PTR_ERR(info);
861 	if (info != NULL)
862 		return add_dataflash_otp(spi, info->name, info->nr_pages,
863 				info->pagesize, info->pageoffset,
864 				(info->flags & SUP_POW2PS) ? 'd' : 'c');
865 
866 	/*
867 	 * Older chips support only legacy commands, identifing
868 	 * capacity using bits in the status byte.
869 	 */
870 	status = dataflash_status(spi);
871 	if (status <= 0 || status == 0xff) {
872 		dev_dbg(&spi->dev, "status error %d\n", status);
873 		if (status == 0 || status == 0xff)
874 			status = -ENODEV;
875 		return status;
876 	}
877 
878 	/* if there's a device there, assume it's dataflash.
879 	 * board setup should have set spi->max_speed_max to
880 	 * match f(car) for continuous reads, mode 0 or 3.
881 	 */
882 	switch (status & 0x3c) {
883 	case 0x0c:	/* 0 0 1 1 x x */
884 		status = add_dataflash(spi, "AT45DB011B", 512, 264, 9);
885 		break;
886 	case 0x14:	/* 0 1 0 1 x x */
887 		status = add_dataflash(spi, "AT45DB021B", 1024, 264, 9);
888 		break;
889 	case 0x1c:	/* 0 1 1 1 x x */
890 		status = add_dataflash(spi, "AT45DB041x", 2048, 264, 9);
891 		break;
892 	case 0x24:	/* 1 0 0 1 x x */
893 		status = add_dataflash(spi, "AT45DB081B", 4096, 264, 9);
894 		break;
895 	case 0x2c:	/* 1 0 1 1 x x */
896 		status = add_dataflash(spi, "AT45DB161x", 4096, 528, 10);
897 		break;
898 	case 0x34:	/* 1 1 0 1 x x */
899 		status = add_dataflash(spi, "AT45DB321x", 8192, 528, 10);
900 		break;
901 	case 0x38:	/* 1 1 1 x x x */
902 	case 0x3c:
903 		status = add_dataflash(spi, "AT45DB642x", 8192, 1056, 11);
904 		break;
905 	/* obsolete AT45DB1282 not (yet?) supported */
906 	default:
907 		dev_info(&spi->dev, "unsupported device (%x)\n",
908 				status & 0x3c);
909 		status = -ENODEV;
910 	}
911 
912 	if (status < 0)
913 		dev_dbg(&spi->dev, "add_dataflash --> %d\n", status);
914 
915 	return status;
916 }
917 
918 static void dataflash_remove(struct spi_device *spi)
919 {
920 	struct dataflash	*flash = spi_get_drvdata(spi);
921 
922 	dev_dbg(&spi->dev, "remove\n");
923 
924 	WARN_ON(mtd_device_unregister(&flash->mtd));
925 
926 	kfree(flash);
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 	.probe		= dataflash_probe,
935 	.remove		= dataflash_remove,
936 	.id_table	= dataflash_spi_ids,
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