xref: /linux/drivers/mtd/devices/mtd_dataflash.c (revision b43ab901d671e3e3cad425ea5e9a3c74e266dcdd)
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/init.h>
14 #include <linux/slab.h>
15 #include <linux/delay.h>
16 #include <linux/device.h>
17 #include <linux/mutex.h>
18 #include <linux/err.h>
19 #include <linux/math64.h>
20 #include <linux/of.h>
21 #include <linux/of_device.h>
22 
23 #include <linux/spi/spi.h>
24 #include <linux/spi/flash.h>
25 
26 #include <linux/mtd/mtd.h>
27 #include <linux/mtd/partitions.h>
28 
29 /*
30  * DataFlash is a kind of SPI flash.  Most AT45 chips have two buffers in
31  * each chip, which may be used for double buffered I/O; but this driver
32  * doesn't (yet) use these for any kind of i/o overlap or prefetching.
33  *
34  * Sometimes DataFlash is packaged in MMC-format cards, although the
35  * MMC stack can't (yet?) distinguish between MMC and DataFlash
36  * protocols during enumeration.
37  */
38 
39 /* reads can bypass the buffers */
40 #define OP_READ_CONTINUOUS	0xE8
41 #define OP_READ_PAGE		0xD2
42 
43 /* group B requests can run even while status reports "busy" */
44 #define OP_READ_STATUS		0xD7	/* group B */
45 
46 /* move data between host and buffer */
47 #define OP_READ_BUFFER1		0xD4	/* group B */
48 #define OP_READ_BUFFER2		0xD6	/* group B */
49 #define OP_WRITE_BUFFER1	0x84	/* group B */
50 #define OP_WRITE_BUFFER2	0x87	/* group B */
51 
52 /* erasing flash */
53 #define OP_ERASE_PAGE		0x81
54 #define OP_ERASE_BLOCK		0x50
55 
56 /* move data between buffer and flash */
57 #define OP_TRANSFER_BUF1	0x53
58 #define OP_TRANSFER_BUF2	0x55
59 #define OP_MREAD_BUFFER1	0xD4
60 #define OP_MREAD_BUFFER2	0xD6
61 #define OP_MWERASE_BUFFER1	0x83
62 #define OP_MWERASE_BUFFER2	0x86
63 #define OP_MWRITE_BUFFER1	0x88	/* sector must be pre-erased */
64 #define OP_MWRITE_BUFFER2	0x89	/* sector must be pre-erased */
65 
66 /* write to buffer, then write-erase to flash */
67 #define OP_PROGRAM_VIA_BUF1	0x82
68 #define OP_PROGRAM_VIA_BUF2	0x85
69 
70 /* compare buffer to flash */
71 #define OP_COMPARE_BUF1		0x60
72 #define OP_COMPARE_BUF2		0x61
73 
74 /* read flash to buffer, then write-erase to flash */
75 #define OP_REWRITE_VIA_BUF1	0x58
76 #define OP_REWRITE_VIA_BUF2	0x59
77 
78 /* newer chips report JEDEC manufacturer and device IDs; chip
79  * serial number and OTP bits; and per-sector writeprotect.
80  */
81 #define OP_READ_ID		0x9F
82 #define OP_READ_SECURITY	0x77
83 #define OP_WRITE_SECURITY_REVC	0x9A
84 #define OP_WRITE_SECURITY	0x9B	/* revision D */
85 
86 
87 struct dataflash {
88 	uint8_t			command[4];
89 	char			name[24];
90 
91 	unsigned		partitioned:1;
92 
93 	unsigned short		page_offset;	/* offset in flash address */
94 	unsigned int		page_size;	/* of bytes per page */
95 
96 	struct mutex		lock;
97 	struct spi_device	*spi;
98 
99 	struct mtd_info		mtd;
100 };
101 
102 #ifdef CONFIG_OF
103 static const struct of_device_id dataflash_dt_ids[] = {
104 	{ .compatible = "atmel,at45", },
105 	{ .compatible = "atmel,dataflash", },
106 	{ /* sentinel */ }
107 };
108 #else
109 #define dataflash_dt_ids NULL
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 			pr_debug("%s: status %d?\n",
137 					dev_name(&spi->dev), status);
138 			status = 0;
139 		}
140 
141 		if (status & (1 << 7))	/* RDY/nBSY */
142 			return status;
143 
144 		msleep(3);
145 	}
146 }
147 
148 /* ......................................................................... */
149 
150 /*
151  * Erase pages of flash.
152  */
153 static int dataflash_erase(struct mtd_info *mtd, struct erase_info *instr)
154 {
155 	struct dataflash	*priv = mtd->priv;
156 	struct spi_device	*spi = priv->spi;
157 	struct spi_transfer	x = { .tx_dma = 0, };
158 	struct spi_message	msg;
159 	unsigned		blocksize = priv->page_size << 3;
160 	uint8_t			*command;
161 	uint32_t		rem;
162 
163 	pr_debug("%s: erase addr=0x%llx len 0x%llx\n",
164 	      dev_name(&spi->dev), (long long)instr->addr,
165 	      (long long)instr->len);
166 
167 	/* Sanity checks */
168 	if (instr->addr + instr->len > mtd->size)
169 		return -EINVAL;
170 	div_u64_rem(instr->len, priv->page_size, &rem);
171 	if (rem)
172 		return -EINVAL;
173 	div_u64_rem(instr->addr, priv->page_size, &rem);
174 	if (rem)
175 		return -EINVAL;
176 
177 	spi_message_init(&msg);
178 
179 	x.tx_buf = command = priv->command;
180 	x.len = 4;
181 	spi_message_add_tail(&x, &msg);
182 
183 	mutex_lock(&priv->lock);
184 	while (instr->len > 0) {
185 		unsigned int	pageaddr;
186 		int		status;
187 		int		do_block;
188 
189 		/* Calculate flash page address; use block erase (for speed) if
190 		 * we're at a block boundary and need to erase the whole block.
191 		 */
192 		pageaddr = div_u64(instr->addr, priv->page_size);
193 		do_block = (pageaddr & 0x7) == 0 && instr->len >= blocksize;
194 		pageaddr = pageaddr << priv->page_offset;
195 
196 		command[0] = do_block ? OP_ERASE_BLOCK : OP_ERASE_PAGE;
197 		command[1] = (uint8_t)(pageaddr >> 16);
198 		command[2] = (uint8_t)(pageaddr >> 8);
199 		command[3] = 0;
200 
201 		pr_debug("ERASE %s: (%x) %x %x %x [%i]\n",
202 			do_block ? "block" : "page",
203 			command[0], command[1], command[2], command[3],
204 			pageaddr);
205 
206 		status = spi_sync(spi, &msg);
207 		(void) dataflash_waitready(spi);
208 
209 		if (status < 0) {
210 			printk(KERN_ERR "%s: erase %x, err %d\n",
211 				dev_name(&spi->dev), pageaddr, status);
212 			/* REVISIT:  can retry instr->retries times; or
213 			 * giveup and instr->fail_addr = instr->addr;
214 			 */
215 			continue;
216 		}
217 
218 		if (do_block) {
219 			instr->addr += blocksize;
220 			instr->len -= blocksize;
221 		} else {
222 			instr->addr += priv->page_size;
223 			instr->len -= priv->page_size;
224 		}
225 	}
226 	mutex_unlock(&priv->lock);
227 
228 	/* Inform MTD subsystem that erase is complete */
229 	instr->state = MTD_ERASE_DONE;
230 	mtd_erase_callback(instr);
231 
232 	return 0;
233 }
234 
235 /*
236  * Read from the DataFlash device.
237  *   from   : Start offset in flash device
238  *   len    : Amount to read
239  *   retlen : About of data actually read
240  *   buf    : Buffer containing the data
241  */
242 static int dataflash_read(struct mtd_info *mtd, loff_t from, size_t len,
243 			       size_t *retlen, u_char *buf)
244 {
245 	struct dataflash	*priv = mtd->priv;
246 	struct spi_transfer	x[2] = { { .tx_dma = 0, }, };
247 	struct spi_message	msg;
248 	unsigned int		addr;
249 	uint8_t			*command;
250 	int			status;
251 
252 	pr_debug("%s: read 0x%x..0x%x\n", dev_name(&priv->spi->dev),
253 			(unsigned)from, (unsigned)(from + len));
254 
255 	*retlen = 0;
256 
257 	/* Sanity checks */
258 	if (!len)
259 		return 0;
260 	if (from + len > mtd->size)
261 		return -EINVAL;
262 
263 	/* Calculate flash page/byte address */
264 	addr = (((unsigned)from / priv->page_size) << priv->page_offset)
265 		+ ((unsigned)from % priv->page_size);
266 
267 	command = priv->command;
268 
269 	pr_debug("READ: (%x) %x %x %x\n",
270 		command[0], command[1], command[2], command[3]);
271 
272 	spi_message_init(&msg);
273 
274 	x[0].tx_buf = command;
275 	x[0].len = 8;
276 	spi_message_add_tail(&x[0], &msg);
277 
278 	x[1].rx_buf = buf;
279 	x[1].len = len;
280 	spi_message_add_tail(&x[1], &msg);
281 
282 	mutex_lock(&priv->lock);
283 
284 	/* Continuous read, max clock = f(car) which may be less than
285 	 * the peak rate available.  Some chips support commands with
286 	 * fewer "don't care" bytes.  Both buffers stay unchanged.
287 	 */
288 	command[0] = OP_READ_CONTINUOUS;
289 	command[1] = (uint8_t)(addr >> 16);
290 	command[2] = (uint8_t)(addr >> 8);
291 	command[3] = (uint8_t)(addr >> 0);
292 	/* plus 4 "don't care" bytes */
293 
294 	status = spi_sync(priv->spi, &msg);
295 	mutex_unlock(&priv->lock);
296 
297 	if (status >= 0) {
298 		*retlen = msg.actual_length - 8;
299 		status = 0;
300 	} else
301 		pr_debug("%s: read %x..%x --> %d\n",
302 			dev_name(&priv->spi->dev),
303 			(unsigned)from, (unsigned)(from + len),
304 			status);
305 	return status;
306 }
307 
308 /*
309  * Write to the DataFlash device.
310  *   to     : Start offset in flash device
311  *   len    : Amount to write
312  *   retlen : Amount of data actually written
313  *   buf    : Buffer containing the data
314  */
315 static int dataflash_write(struct mtd_info *mtd, loff_t to, size_t len,
316 				size_t * retlen, const u_char * buf)
317 {
318 	struct dataflash	*priv = mtd->priv;
319 	struct spi_device	*spi = priv->spi;
320 	struct spi_transfer	x[2] = { { .tx_dma = 0, }, };
321 	struct spi_message	msg;
322 	unsigned int		pageaddr, addr, offset, writelen;
323 	size_t			remaining = len;
324 	u_char			*writebuf = (u_char *) buf;
325 	int			status = -EINVAL;
326 	uint8_t			*command;
327 
328 	pr_debug("%s: write 0x%x..0x%x\n",
329 		dev_name(&spi->dev), (unsigned)to, (unsigned)(to + len));
330 
331 	*retlen = 0;
332 
333 	/* Sanity checks */
334 	if (!len)
335 		return 0;
336 	if ((to + len) > mtd->size)
337 		return -EINVAL;
338 
339 	spi_message_init(&msg);
340 
341 	x[0].tx_buf = command = priv->command;
342 	x[0].len = 4;
343 	spi_message_add_tail(&x[0], &msg);
344 
345 	pageaddr = ((unsigned)to / priv->page_size);
346 	offset = ((unsigned)to % priv->page_size);
347 	if (offset + len > priv->page_size)
348 		writelen = priv->page_size - offset;
349 	else
350 		writelen = len;
351 
352 	mutex_lock(&priv->lock);
353 	while (remaining > 0) {
354 		pr_debug("write @ %i:%i len=%i\n",
355 			pageaddr, offset, writelen);
356 
357 		/* REVISIT:
358 		 * (a) each page in a sector must be rewritten at least
359 		 *     once every 10K sibling erase/program operations.
360 		 * (b) for pages that are already erased, we could
361 		 *     use WRITE+MWRITE not PROGRAM for ~30% speedup.
362 		 * (c) WRITE to buffer could be done while waiting for
363 		 *     a previous MWRITE/MWERASE to complete ...
364 		 * (d) error handling here seems to be mostly missing.
365 		 *
366 		 * Two persistent bits per page, plus a per-sector counter,
367 		 * could support (a) and (b) ... we might consider using
368 		 * the second half of sector zero, which is just one block,
369 		 * to track that state.  (On AT91, that sector should also
370 		 * support boot-from-DataFlash.)
371 		 */
372 
373 		addr = pageaddr << priv->page_offset;
374 
375 		/* (1) Maybe transfer partial page to Buffer1 */
376 		if (writelen != priv->page_size) {
377 			command[0] = OP_TRANSFER_BUF1;
378 			command[1] = (addr & 0x00FF0000) >> 16;
379 			command[2] = (addr & 0x0000FF00) >> 8;
380 			command[3] = 0;
381 
382 			pr_debug("TRANSFER: (%x) %x %x %x\n",
383 				command[0], command[1], command[2], command[3]);
384 
385 			status = spi_sync(spi, &msg);
386 			if (status < 0)
387 				pr_debug("%s: xfer %u -> %d\n",
388 					dev_name(&spi->dev), addr, status);
389 
390 			(void) dataflash_waitready(priv->spi);
391 		}
392 
393 		/* (2) Program full page via Buffer1 */
394 		addr += offset;
395 		command[0] = OP_PROGRAM_VIA_BUF1;
396 		command[1] = (addr & 0x00FF0000) >> 16;
397 		command[2] = (addr & 0x0000FF00) >> 8;
398 		command[3] = (addr & 0x000000FF);
399 
400 		pr_debug("PROGRAM: (%x) %x %x %x\n",
401 			command[0], command[1], command[2], command[3]);
402 
403 		x[1].tx_buf = writebuf;
404 		x[1].len = writelen;
405 		spi_message_add_tail(x + 1, &msg);
406 		status = spi_sync(spi, &msg);
407 		spi_transfer_del(x + 1);
408 		if (status < 0)
409 			pr_debug("%s: pgm %u/%u -> %d\n",
410 				dev_name(&spi->dev), addr, writelen, status);
411 
412 		(void) dataflash_waitready(priv->spi);
413 
414 
415 #ifdef CONFIG_MTD_DATAFLASH_WRITE_VERIFY
416 
417 		/* (3) Compare to Buffer1 */
418 		addr = pageaddr << priv->page_offset;
419 		command[0] = OP_COMPARE_BUF1;
420 		command[1] = (addr & 0x00FF0000) >> 16;
421 		command[2] = (addr & 0x0000FF00) >> 8;
422 		command[3] = 0;
423 
424 		pr_debug("COMPARE: (%x) %x %x %x\n",
425 			command[0], command[1], command[2], command[3]);
426 
427 		status = spi_sync(spi, &msg);
428 		if (status < 0)
429 			pr_debug("%s: compare %u -> %d\n",
430 				dev_name(&spi->dev), addr, status);
431 
432 		status = dataflash_waitready(priv->spi);
433 
434 		/* Check result of the compare operation */
435 		if (status & (1 << 6)) {
436 			printk(KERN_ERR "%s: compare page %u, err %d\n",
437 				dev_name(&spi->dev), pageaddr, status);
438 			remaining = 0;
439 			status = -EIO;
440 			break;
441 		} else
442 			status = 0;
443 
444 #endif	/* CONFIG_MTD_DATAFLASH_WRITE_VERIFY */
445 
446 		remaining = remaining - writelen;
447 		pageaddr++;
448 		offset = 0;
449 		writebuf += writelen;
450 		*retlen += writelen;
451 
452 		if (remaining > priv->page_size)
453 			writelen = priv->page_size;
454 		else
455 			writelen = remaining;
456 	}
457 	mutex_unlock(&priv->lock);
458 
459 	return status;
460 }
461 
462 /* ......................................................................... */
463 
464 #ifdef CONFIG_MTD_DATAFLASH_OTP
465 
466 static int dataflash_get_otp_info(struct mtd_info *mtd,
467 		struct otp_info *info, size_t len)
468 {
469 	/* Report both blocks as identical:  bytes 0..64, locked.
470 	 * Unless the user block changed from all-ones, we can't
471 	 * tell whether it's still writable; so we assume it isn't.
472 	 */
473 	info->start = 0;
474 	info->length = 64;
475 	info->locked = 1;
476 	return sizeof(*info);
477 }
478 
479 static ssize_t otp_read(struct spi_device *spi, unsigned base,
480 		uint8_t *buf, loff_t off, size_t len)
481 {
482 	struct spi_message	m;
483 	size_t			l;
484 	uint8_t			*scratch;
485 	struct spi_transfer	t;
486 	int			status;
487 
488 	if (off > 64)
489 		return -EINVAL;
490 
491 	if ((off + len) > 64)
492 		len = 64 - off;
493 	if (len == 0)
494 		return len;
495 
496 	spi_message_init(&m);
497 
498 	l = 4 + base + off + len;
499 	scratch = kzalloc(l, GFP_KERNEL);
500 	if (!scratch)
501 		return -ENOMEM;
502 
503 	/* OUT: OP_READ_SECURITY, 3 don't-care bytes, zeroes
504 	 * IN:  ignore 4 bytes, data bytes 0..N (max 127)
505 	 */
506 	scratch[0] = OP_READ_SECURITY;
507 
508 	memset(&t, 0, sizeof t);
509 	t.tx_buf = scratch;
510 	t.rx_buf = scratch;
511 	t.len = l;
512 	spi_message_add_tail(&t, &m);
513 
514 	dataflash_waitready(spi);
515 
516 	status = spi_sync(spi, &m);
517 	if (status >= 0) {
518 		memcpy(buf, scratch + 4 + base + off, len);
519 		status = len;
520 	}
521 
522 	kfree(scratch);
523 	return status;
524 }
525 
526 static int dataflash_read_fact_otp(struct mtd_info *mtd,
527 		loff_t from, size_t len, size_t *retlen, u_char *buf)
528 {
529 	struct dataflash	*priv = mtd->priv;
530 	int			status;
531 
532 	/* 64 bytes, from 0..63 ... start at 64 on-chip */
533 	mutex_lock(&priv->lock);
534 	status = otp_read(priv->spi, 64, buf, from, len);
535 	mutex_unlock(&priv->lock);
536 
537 	if (status < 0)
538 		return status;
539 	*retlen = status;
540 	return 0;
541 }
542 
543 static int dataflash_read_user_otp(struct mtd_info *mtd,
544 		loff_t from, size_t len, size_t *retlen, u_char *buf)
545 {
546 	struct dataflash	*priv = mtd->priv;
547 	int			status;
548 
549 	/* 64 bytes, from 0..63 ... start at 0 on-chip */
550 	mutex_lock(&priv->lock);
551 	status = otp_read(priv->spi, 0, buf, from, len);
552 	mutex_unlock(&priv->lock);
553 
554 	if (status < 0)
555 		return status;
556 	*retlen = status;
557 	return 0;
558 }
559 
560 static int dataflash_write_user_otp(struct mtd_info *mtd,
561 		loff_t from, size_t len, size_t *retlen, u_char *buf)
562 {
563 	struct spi_message	m;
564 	const size_t		l = 4 + 64;
565 	uint8_t			*scratch;
566 	struct spi_transfer	t;
567 	struct dataflash	*priv = mtd->priv;
568 	int			status;
569 
570 	if (len > 64)
571 		return -EINVAL;
572 
573 	/* Strictly speaking, we *could* truncate the write ... but
574 	 * let's not do that for the only write that's ever possible.
575 	 */
576 	if ((from + len) > 64)
577 		return -EINVAL;
578 
579 	/* OUT: OP_WRITE_SECURITY, 3 zeroes, 64 data-or-zero bytes
580 	 * IN:  ignore all
581 	 */
582 	scratch = kzalloc(l, GFP_KERNEL);
583 	if (!scratch)
584 		return -ENOMEM;
585 	scratch[0] = OP_WRITE_SECURITY;
586 	memcpy(scratch + 4 + from, buf, len);
587 
588 	spi_message_init(&m);
589 
590 	memset(&t, 0, sizeof t);
591 	t.tx_buf = scratch;
592 	t.len = l;
593 	spi_message_add_tail(&t, &m);
594 
595 	/* Write the OTP bits, if they've not yet been written.
596 	 * This modifies SRAM buffer1.
597 	 */
598 	mutex_lock(&priv->lock);
599 	dataflash_waitready(priv->spi);
600 	status = spi_sync(priv->spi, &m);
601 	mutex_unlock(&priv->lock);
602 
603 	kfree(scratch);
604 
605 	if (status >= 0) {
606 		status = 0;
607 		*retlen = len;
608 	}
609 	return status;
610 }
611 
612 static char *otp_setup(struct mtd_info *device, char revision)
613 {
614 	device->get_fact_prot_info = dataflash_get_otp_info;
615 	device->read_fact_prot_reg = dataflash_read_fact_otp;
616 	device->get_user_prot_info = dataflash_get_otp_info;
617 	device->read_user_prot_reg = dataflash_read_user_otp;
618 
619 	/* rev c parts (at45db321c and at45db1281 only!) use a
620 	 * different write procedure; not (yet?) implemented.
621 	 */
622 	if (revision > 'c')
623 		device->write_user_prot_reg = dataflash_write_user_otp;
624 
625 	return ", OTP";
626 }
627 
628 #else
629 
630 static char *otp_setup(struct mtd_info *device, char revision)
631 {
632 	return " (OTP)";
633 }
634 
635 #endif
636 
637 /* ......................................................................... */
638 
639 /*
640  * Register DataFlash device with MTD subsystem.
641  */
642 static int __devinit
643 add_dataflash_otp(struct spi_device *spi, char *name,
644 		int nr_pages, int pagesize, int pageoffset, char revision)
645 {
646 	struct dataflash		*priv;
647 	struct mtd_info			*device;
648 	struct mtd_part_parser_data	ppdata;
649 	struct flash_platform_data	*pdata = spi->dev.platform_data;
650 	char				*otp_tag = "";
651 	int				err = 0;
652 
653 	priv = kzalloc(sizeof *priv, GFP_KERNEL);
654 	if (!priv)
655 		return -ENOMEM;
656 
657 	mutex_init(&priv->lock);
658 	priv->spi = spi;
659 	priv->page_size = pagesize;
660 	priv->page_offset = pageoffset;
661 
662 	/* name must be usable with cmdlinepart */
663 	sprintf(priv->name, "spi%d.%d-%s",
664 			spi->master->bus_num, spi->chip_select,
665 			name);
666 
667 	device = &priv->mtd;
668 	device->name = (pdata && pdata->name) ? pdata->name : priv->name;
669 	device->size = nr_pages * pagesize;
670 	device->erasesize = pagesize;
671 	device->writesize = pagesize;
672 	device->owner = THIS_MODULE;
673 	device->type = MTD_DATAFLASH;
674 	device->flags = MTD_WRITEABLE;
675 	device->erase = dataflash_erase;
676 	device->read = dataflash_read;
677 	device->write = dataflash_write;
678 	device->priv = priv;
679 
680 	device->dev.parent = &spi->dev;
681 
682 	if (revision >= 'c')
683 		otp_tag = otp_setup(device, revision);
684 
685 	dev_info(&spi->dev, "%s (%lld KBytes) pagesize %d bytes%s\n",
686 			name, (long long)((device->size + 1023) >> 10),
687 			pagesize, otp_tag);
688 	dev_set_drvdata(&spi->dev, priv);
689 
690 	ppdata.of_node = spi->dev.of_node;
691 	err = mtd_device_parse_register(device, NULL, &ppdata,
692 			pdata ? pdata->parts : NULL,
693 			pdata ? pdata->nr_parts : 0);
694 
695 	if (!err)
696 		return 0;
697 
698 	dev_set_drvdata(&spi->dev, NULL);
699 	kfree(priv);
700 	return err;
701 }
702 
703 static inline int __devinit
704 add_dataflash(struct spi_device *spi, char *name,
705 		int nr_pages, int pagesize, int pageoffset)
706 {
707 	return add_dataflash_otp(spi, name, nr_pages, pagesize,
708 			pageoffset, 0);
709 }
710 
711 struct flash_info {
712 	char		*name;
713 
714 	/* JEDEC id has a high byte of zero plus three data bytes:
715 	 * the manufacturer id, then a two byte device id.
716 	 */
717 	uint32_t	jedec_id;
718 
719 	/* The size listed here is what works with OP_ERASE_PAGE. */
720 	unsigned	nr_pages;
721 	uint16_t	pagesize;
722 	uint16_t	pageoffset;
723 
724 	uint16_t	flags;
725 #define SUP_POW2PS	0x0002		/* supports 2^N byte pages */
726 #define IS_POW2PS	0x0001		/* uses 2^N byte pages */
727 };
728 
729 static struct flash_info __devinitdata dataflash_data [] = {
730 
731 	/*
732 	 * NOTE:  chips with SUP_POW2PS (rev D and up) need two entries,
733 	 * one with IS_POW2PS and the other without.  The entry with the
734 	 * non-2^N byte page size can't name exact chip revisions without
735 	 * losing backwards compatibility for cmdlinepart.
736 	 *
737 	 * These newer chips also support 128-byte security registers (with
738 	 * 64 bytes one-time-programmable) and software write-protection.
739 	 */
740 	{ "AT45DB011B",  0x1f2200, 512, 264, 9, SUP_POW2PS},
741 	{ "at45db011d",  0x1f2200, 512, 256, 8, SUP_POW2PS | IS_POW2PS},
742 
743 	{ "AT45DB021B",  0x1f2300, 1024, 264, 9, SUP_POW2PS},
744 	{ "at45db021d",  0x1f2300, 1024, 256, 8, SUP_POW2PS | IS_POW2PS},
745 
746 	{ "AT45DB041x",  0x1f2400, 2048, 264, 9, SUP_POW2PS},
747 	{ "at45db041d",  0x1f2400, 2048, 256, 8, SUP_POW2PS | IS_POW2PS},
748 
749 	{ "AT45DB081B",  0x1f2500, 4096, 264, 9, SUP_POW2PS},
750 	{ "at45db081d",  0x1f2500, 4096, 256, 8, SUP_POW2PS | IS_POW2PS},
751 
752 	{ "AT45DB161x",  0x1f2600, 4096, 528, 10, SUP_POW2PS},
753 	{ "at45db161d",  0x1f2600, 4096, 512, 9, SUP_POW2PS | IS_POW2PS},
754 
755 	{ "AT45DB321x",  0x1f2700, 8192, 528, 10, 0},		/* rev C */
756 
757 	{ "AT45DB321x",  0x1f2701, 8192, 528, 10, SUP_POW2PS},
758 	{ "at45db321d",  0x1f2701, 8192, 512, 9, SUP_POW2PS | IS_POW2PS},
759 
760 	{ "AT45DB642x",  0x1f2800, 8192, 1056, 11, SUP_POW2PS},
761 	{ "at45db642d",  0x1f2800, 8192, 1024, 10, SUP_POW2PS | IS_POW2PS},
762 };
763 
764 static struct flash_info *__devinit jedec_probe(struct spi_device *spi)
765 {
766 	int			tmp;
767 	uint8_t			code = OP_READ_ID;
768 	uint8_t			id[3];
769 	uint32_t		jedec;
770 	struct flash_info	*info;
771 	int status;
772 
773 	/* JEDEC also defines an optional "extended device information"
774 	 * string for after vendor-specific data, after the three bytes
775 	 * we use here.  Supporting some chips might require using it.
776 	 *
777 	 * If the vendor ID isn't Atmel's (0x1f), assume this call failed.
778 	 * That's not an error; only rev C and newer chips handle it, and
779 	 * only Atmel sells these chips.
780 	 */
781 	tmp = spi_write_then_read(spi, &code, 1, id, 3);
782 	if (tmp < 0) {
783 		pr_debug("%s: error %d reading JEDEC ID\n",
784 			dev_name(&spi->dev), tmp);
785 		return ERR_PTR(tmp);
786 	}
787 	if (id[0] != 0x1f)
788 		return NULL;
789 
790 	jedec = id[0];
791 	jedec = jedec << 8;
792 	jedec |= id[1];
793 	jedec = jedec << 8;
794 	jedec |= id[2];
795 
796 	for (tmp = 0, info = dataflash_data;
797 			tmp < ARRAY_SIZE(dataflash_data);
798 			tmp++, info++) {
799 		if (info->jedec_id == jedec) {
800 			pr_debug("%s: OTP, sector protect%s\n",
801 				dev_name(&spi->dev),
802 				(info->flags & SUP_POW2PS)
803 					? ", binary pagesize" : ""
804 				);
805 			if (info->flags & SUP_POW2PS) {
806 				status = dataflash_status(spi);
807 				if (status < 0) {
808 					pr_debug("%s: status error %d\n",
809 						dev_name(&spi->dev), status);
810 					return ERR_PTR(status);
811 				}
812 				if (status & 0x1) {
813 					if (info->flags & IS_POW2PS)
814 						return info;
815 				} else {
816 					if (!(info->flags & IS_POW2PS))
817 						return info;
818 				}
819 			} else
820 				return info;
821 		}
822 	}
823 
824 	/*
825 	 * Treat other chips as errors ... we won't know the right page
826 	 * size (it might be binary) even when we can tell which density
827 	 * class is involved (legacy chip id scheme).
828 	 */
829 	dev_warn(&spi->dev, "JEDEC id %06x not handled\n", jedec);
830 	return ERR_PTR(-ENODEV);
831 }
832 
833 /*
834  * Detect and initialize DataFlash device, using JEDEC IDs on newer chips
835  * or else the ID code embedded in the status bits:
836  *
837  *   Device      Density         ID code          #Pages PageSize  Offset
838  *   AT45DB011B  1Mbit   (128K)  xx0011xx (0x0c)    512    264      9
839  *   AT45DB021B  2Mbit   (256K)  xx0101xx (0x14)   1024    264      9
840  *   AT45DB041B  4Mbit   (512K)  xx0111xx (0x1c)   2048    264      9
841  *   AT45DB081B  8Mbit   (1M)    xx1001xx (0x24)   4096    264      9
842  *   AT45DB0161B 16Mbit  (2M)    xx1011xx (0x2c)   4096    528     10
843  *   AT45DB0321B 32Mbit  (4M)    xx1101xx (0x34)   8192    528     10
844  *   AT45DB0642  64Mbit  (8M)    xx111xxx (0x3c)   8192   1056     11
845  *   AT45DB1282  128Mbit (16M)   xx0100xx (0x10)  16384   1056     11
846  */
847 static int __devinit dataflash_probe(struct spi_device *spi)
848 {
849 	int status;
850 	struct flash_info	*info;
851 
852 	/*
853 	 * Try to detect dataflash by JEDEC ID.
854 	 * If it succeeds we know we have either a C or D part.
855 	 * D will support power of 2 pagesize option.
856 	 * Both support the security register, though with different
857 	 * write procedures.
858 	 */
859 	info = jedec_probe(spi);
860 	if (IS_ERR(info))
861 		return PTR_ERR(info);
862 	if (info != NULL)
863 		return add_dataflash_otp(spi, info->name, info->nr_pages,
864 				info->pagesize, info->pageoffset,
865 				(info->flags & SUP_POW2PS) ? 'd' : 'c');
866 
867 	/*
868 	 * Older chips support only legacy commands, identifing
869 	 * capacity using bits in the status byte.
870 	 */
871 	status = dataflash_status(spi);
872 	if (status <= 0 || status == 0xff) {
873 		pr_debug("%s: status error %d\n",
874 				dev_name(&spi->dev), status);
875 		if (status == 0 || status == 0xff)
876 			status = -ENODEV;
877 		return status;
878 	}
879 
880 	/* if there's a device there, assume it's dataflash.
881 	 * board setup should have set spi->max_speed_max to
882 	 * match f(car) for continuous reads, mode 0 or 3.
883 	 */
884 	switch (status & 0x3c) {
885 	case 0x0c:	/* 0 0 1 1 x x */
886 		status = add_dataflash(spi, "AT45DB011B", 512, 264, 9);
887 		break;
888 	case 0x14:	/* 0 1 0 1 x x */
889 		status = add_dataflash(spi, "AT45DB021B", 1024, 264, 9);
890 		break;
891 	case 0x1c:	/* 0 1 1 1 x x */
892 		status = add_dataflash(spi, "AT45DB041x", 2048, 264, 9);
893 		break;
894 	case 0x24:	/* 1 0 0 1 x x */
895 		status = add_dataflash(spi, "AT45DB081B", 4096, 264, 9);
896 		break;
897 	case 0x2c:	/* 1 0 1 1 x x */
898 		status = add_dataflash(spi, "AT45DB161x", 4096, 528, 10);
899 		break;
900 	case 0x34:	/* 1 1 0 1 x x */
901 		status = add_dataflash(spi, "AT45DB321x", 8192, 528, 10);
902 		break;
903 	case 0x38:	/* 1 1 1 x x x */
904 	case 0x3c:
905 		status = add_dataflash(spi, "AT45DB642x", 8192, 1056, 11);
906 		break;
907 	/* obsolete AT45DB1282 not (yet?) supported */
908 	default:
909 		pr_debug("%s: unsupported device (%x)\n", dev_name(&spi->dev),
910 				status & 0x3c);
911 		status = -ENODEV;
912 	}
913 
914 	if (status < 0)
915 		pr_debug("%s: add_dataflash --> %d\n", dev_name(&spi->dev),
916 				status);
917 
918 	return status;
919 }
920 
921 static int __devexit dataflash_remove(struct spi_device *spi)
922 {
923 	struct dataflash	*flash = dev_get_drvdata(&spi->dev);
924 	int			status;
925 
926 	pr_debug("%s: remove\n", dev_name(&spi->dev));
927 
928 	status = mtd_device_unregister(&flash->mtd);
929 	if (status == 0) {
930 		dev_set_drvdata(&spi->dev, NULL);
931 		kfree(flash);
932 	}
933 	return status;
934 }
935 
936 static struct spi_driver dataflash_driver = {
937 	.driver = {
938 		.name		= "mtd_dataflash",
939 		.owner		= THIS_MODULE,
940 		.of_match_table = dataflash_dt_ids,
941 	},
942 
943 	.probe		= dataflash_probe,
944 	.remove		= __devexit_p(dataflash_remove),
945 
946 	/* FIXME:  investigate suspend and resume... */
947 };
948 
949 static int __init dataflash_init(void)
950 {
951 	return spi_register_driver(&dataflash_driver);
952 }
953 module_init(dataflash_init);
954 
955 static void __exit dataflash_exit(void)
956 {
957 	spi_unregister_driver(&dataflash_driver);
958 }
959 module_exit(dataflash_exit);
960 
961 
962 MODULE_LICENSE("GPL");
963 MODULE_AUTHOR("Andrew Victor, David Brownell");
964 MODULE_DESCRIPTION("MTD DataFlash driver");
965 MODULE_ALIAS("spi:mtd_dataflash");
966