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 
21 #include <linux/spi/spi.h>
22 #include <linux/spi/flash.h>
23 
24 #include <linux/mtd/mtd.h>
25 #include <linux/mtd/partitions.h>
26 
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 
86 struct dataflash {
87 	uint8_t			command[4];
88 	char			name[24];
89 
90 	unsigned		partitioned:1;
91 
92 	unsigned short		page_offset;	/* offset in flash address */
93 	unsigned int		page_size;	/* of bytes per page */
94 
95 	struct mutex		lock;
96 	struct spi_device	*spi;
97 
98 	struct mtd_info		mtd;
99 };
100 
101 /* ......................................................................... */
102 
103 /*
104  * Return the status of the DataFlash device.
105  */
106 static inline int dataflash_status(struct spi_device *spi)
107 {
108 	/* NOTE:  at45db321c over 25 MHz wants to write
109 	 * a dummy byte after the opcode...
110 	 */
111 	return spi_w8r8(spi, OP_READ_STATUS);
112 }
113 
114 /*
115  * Poll the DataFlash device until it is READY.
116  * This usually takes 5-20 msec or so; more for sector erase.
117  */
118 static int dataflash_waitready(struct spi_device *spi)
119 {
120 	int	status;
121 
122 	for (;;) {
123 		status = dataflash_status(spi);
124 		if (status < 0) {
125 			DEBUG(MTD_DEBUG_LEVEL1, "%s: status %d?\n",
126 					dev_name(&spi->dev), status);
127 			status = 0;
128 		}
129 
130 		if (status & (1 << 7))	/* RDY/nBSY */
131 			return status;
132 
133 		msleep(3);
134 	}
135 }
136 
137 /* ......................................................................... */
138 
139 /*
140  * Erase pages of flash.
141  */
142 static int dataflash_erase(struct mtd_info *mtd, struct erase_info *instr)
143 {
144 	struct dataflash	*priv = (struct dataflash *)mtd->priv;
145 	struct spi_device	*spi = priv->spi;
146 	struct spi_transfer	x = { .tx_dma = 0, };
147 	struct spi_message	msg;
148 	unsigned		blocksize = priv->page_size << 3;
149 	uint8_t			*command;
150 	uint32_t		rem;
151 
152 	DEBUG(MTD_DEBUG_LEVEL2, "%s: erase addr=0x%llx len 0x%llx\n",
153 	      dev_name(&spi->dev), (long long)instr->addr,
154 	      (long long)instr->len);
155 
156 	/* Sanity checks */
157 	if (instr->addr + instr->len > mtd->size)
158 		return -EINVAL;
159 	div_u64_rem(instr->len, priv->page_size, &rem);
160 	if (rem)
161 		return -EINVAL;
162 	div_u64_rem(instr->addr, priv->page_size, &rem);
163 	if (rem)
164 		return -EINVAL;
165 
166 	spi_message_init(&msg);
167 
168 	x.tx_buf = command = priv->command;
169 	x.len = 4;
170 	spi_message_add_tail(&x, &msg);
171 
172 	mutex_lock(&priv->lock);
173 	while (instr->len > 0) {
174 		unsigned int	pageaddr;
175 		int		status;
176 		int		do_block;
177 
178 		/* Calculate flash page address; use block erase (for speed) if
179 		 * we're at a block boundary and need to erase the whole block.
180 		 */
181 		pageaddr = div_u64(instr->addr, priv->page_size);
182 		do_block = (pageaddr & 0x7) == 0 && instr->len >= blocksize;
183 		pageaddr = pageaddr << priv->page_offset;
184 
185 		command[0] = do_block ? OP_ERASE_BLOCK : OP_ERASE_PAGE;
186 		command[1] = (uint8_t)(pageaddr >> 16);
187 		command[2] = (uint8_t)(pageaddr >> 8);
188 		command[3] = 0;
189 
190 		DEBUG(MTD_DEBUG_LEVEL3, "ERASE %s: (%x) %x %x %x [%i]\n",
191 			do_block ? "block" : "page",
192 			command[0], command[1], command[2], command[3],
193 			pageaddr);
194 
195 		status = spi_sync(spi, &msg);
196 		(void) dataflash_waitready(spi);
197 
198 		if (status < 0) {
199 			printk(KERN_ERR "%s: erase %x, err %d\n",
200 				dev_name(&spi->dev), pageaddr, status);
201 			/* REVISIT:  can retry instr->retries times; or
202 			 * giveup and instr->fail_addr = instr->addr;
203 			 */
204 			continue;
205 		}
206 
207 		if (do_block) {
208 			instr->addr += blocksize;
209 			instr->len -= blocksize;
210 		} else {
211 			instr->addr += priv->page_size;
212 			instr->len -= priv->page_size;
213 		}
214 	}
215 	mutex_unlock(&priv->lock);
216 
217 	/* Inform MTD subsystem that erase is complete */
218 	instr->state = MTD_ERASE_DONE;
219 	mtd_erase_callback(instr);
220 
221 	return 0;
222 }
223 
224 /*
225  * Read from the DataFlash device.
226  *   from   : Start offset in flash device
227  *   len    : Amount to read
228  *   retlen : About of data actually read
229  *   buf    : Buffer containing the data
230  */
231 static int dataflash_read(struct mtd_info *mtd, loff_t from, size_t len,
232 			       size_t *retlen, u_char *buf)
233 {
234 	struct dataflash	*priv = (struct dataflash *)mtd->priv;
235 	struct spi_transfer	x[2] = { { .tx_dma = 0, }, };
236 	struct spi_message	msg;
237 	unsigned int		addr;
238 	uint8_t			*command;
239 	int			status;
240 
241 	DEBUG(MTD_DEBUG_LEVEL2, "%s: read 0x%x..0x%x\n",
242 		dev_name(&priv->spi->dev), (unsigned)from, (unsigned)(from + len));
243 
244 	*retlen = 0;
245 
246 	/* Sanity checks */
247 	if (!len)
248 		return 0;
249 	if (from + len > mtd->size)
250 		return -EINVAL;
251 
252 	/* Calculate flash page/byte address */
253 	addr = (((unsigned)from / priv->page_size) << priv->page_offset)
254 		+ ((unsigned)from % priv->page_size);
255 
256 	command = priv->command;
257 
258 	DEBUG(MTD_DEBUG_LEVEL3, "READ: (%x) %x %x %x\n",
259 		command[0], command[1], command[2], command[3]);
260 
261 	spi_message_init(&msg);
262 
263 	x[0].tx_buf = command;
264 	x[0].len = 8;
265 	spi_message_add_tail(&x[0], &msg);
266 
267 	x[1].rx_buf = buf;
268 	x[1].len = len;
269 	spi_message_add_tail(&x[1], &msg);
270 
271 	mutex_lock(&priv->lock);
272 
273 	/* Continuous read, max clock = f(car) which may be less than
274 	 * the peak rate available.  Some chips support commands with
275 	 * fewer "don't care" bytes.  Both buffers stay unchanged.
276 	 */
277 	command[0] = OP_READ_CONTINUOUS;
278 	command[1] = (uint8_t)(addr >> 16);
279 	command[2] = (uint8_t)(addr >> 8);
280 	command[3] = (uint8_t)(addr >> 0);
281 	/* plus 4 "don't care" bytes */
282 
283 	status = spi_sync(priv->spi, &msg);
284 	mutex_unlock(&priv->lock);
285 
286 	if (status >= 0) {
287 		*retlen = msg.actual_length - 8;
288 		status = 0;
289 	} else
290 		DEBUG(MTD_DEBUG_LEVEL1, "%s: read %x..%x --> %d\n",
291 			dev_name(&priv->spi->dev),
292 			(unsigned)from, (unsigned)(from + len),
293 			status);
294 	return status;
295 }
296 
297 /*
298  * Write to the DataFlash device.
299  *   to     : Start offset in flash device
300  *   len    : Amount to write
301  *   retlen : Amount of data actually written
302  *   buf    : Buffer containing the data
303  */
304 static int dataflash_write(struct mtd_info *mtd, loff_t to, size_t len,
305 				size_t * retlen, const u_char * buf)
306 {
307 	struct dataflash	*priv = (struct dataflash *)mtd->priv;
308 	struct spi_device	*spi = priv->spi;
309 	struct spi_transfer	x[2] = { { .tx_dma = 0, }, };
310 	struct spi_message	msg;
311 	unsigned int		pageaddr, addr, offset, writelen;
312 	size_t			remaining = len;
313 	u_char			*writebuf = (u_char *) buf;
314 	int			status = -EINVAL;
315 	uint8_t			*command;
316 
317 	DEBUG(MTD_DEBUG_LEVEL2, "%s: write 0x%x..0x%x\n",
318 		dev_name(&spi->dev), (unsigned)to, (unsigned)(to + len));
319 
320 	*retlen = 0;
321 
322 	/* Sanity checks */
323 	if (!len)
324 		return 0;
325 	if ((to + len) > mtd->size)
326 		return -EINVAL;
327 
328 	spi_message_init(&msg);
329 
330 	x[0].tx_buf = command = priv->command;
331 	x[0].len = 4;
332 	spi_message_add_tail(&x[0], &msg);
333 
334 	pageaddr = ((unsigned)to / priv->page_size);
335 	offset = ((unsigned)to % priv->page_size);
336 	if (offset + len > priv->page_size)
337 		writelen = priv->page_size - offset;
338 	else
339 		writelen = len;
340 
341 	mutex_lock(&priv->lock);
342 	while (remaining > 0) {
343 		DEBUG(MTD_DEBUG_LEVEL3, "write @ %i:%i len=%i\n",
344 			pageaddr, offset, writelen);
345 
346 		/* REVISIT:
347 		 * (a) each page in a sector must be rewritten at least
348 		 *     once every 10K sibling erase/program operations.
349 		 * (b) for pages that are already erased, we could
350 		 *     use WRITE+MWRITE not PROGRAM for ~30% speedup.
351 		 * (c) WRITE to buffer could be done while waiting for
352 		 *     a previous MWRITE/MWERASE to complete ...
353 		 * (d) error handling here seems to be mostly missing.
354 		 *
355 		 * Two persistent bits per page, plus a per-sector counter,
356 		 * could support (a) and (b) ... we might consider using
357 		 * the second half of sector zero, which is just one block,
358 		 * to track that state.  (On AT91, that sector should also
359 		 * support boot-from-DataFlash.)
360 		 */
361 
362 		addr = pageaddr << priv->page_offset;
363 
364 		/* (1) Maybe transfer partial page to Buffer1 */
365 		if (writelen != priv->page_size) {
366 			command[0] = OP_TRANSFER_BUF1;
367 			command[1] = (addr & 0x00FF0000) >> 16;
368 			command[2] = (addr & 0x0000FF00) >> 8;
369 			command[3] = 0;
370 
371 			DEBUG(MTD_DEBUG_LEVEL3, "TRANSFER: (%x) %x %x %x\n",
372 				command[0], command[1], command[2], command[3]);
373 
374 			status = spi_sync(spi, &msg);
375 			if (status < 0)
376 				DEBUG(MTD_DEBUG_LEVEL1, "%s: xfer %u -> %d \n",
377 					dev_name(&spi->dev), addr, status);
378 
379 			(void) dataflash_waitready(priv->spi);
380 		}
381 
382 		/* (2) Program full page via Buffer1 */
383 		addr += offset;
384 		command[0] = OP_PROGRAM_VIA_BUF1;
385 		command[1] = (addr & 0x00FF0000) >> 16;
386 		command[2] = (addr & 0x0000FF00) >> 8;
387 		command[3] = (addr & 0x000000FF);
388 
389 		DEBUG(MTD_DEBUG_LEVEL3, "PROGRAM: (%x) %x %x %x\n",
390 			command[0], command[1], command[2], command[3]);
391 
392 		x[1].tx_buf = writebuf;
393 		x[1].len = writelen;
394 		spi_message_add_tail(x + 1, &msg);
395 		status = spi_sync(spi, &msg);
396 		spi_transfer_del(x + 1);
397 		if (status < 0)
398 			DEBUG(MTD_DEBUG_LEVEL1, "%s: pgm %u/%u -> %d \n",
399 				dev_name(&spi->dev), addr, writelen, status);
400 
401 		(void) dataflash_waitready(priv->spi);
402 
403 
404 #ifdef CONFIG_MTD_DATAFLASH_VERIFY_WRITE
405 
406 		/* (3) Compare to Buffer1 */
407 		addr = pageaddr << priv->page_offset;
408 		command[0] = OP_COMPARE_BUF1;
409 		command[1] = (addr & 0x00FF0000) >> 16;
410 		command[2] = (addr & 0x0000FF00) >> 8;
411 		command[3] = 0;
412 
413 		DEBUG(MTD_DEBUG_LEVEL3, "COMPARE: (%x) %x %x %x\n",
414 			command[0], command[1], command[2], command[3]);
415 
416 		status = spi_sync(spi, &msg);
417 		if (status < 0)
418 			DEBUG(MTD_DEBUG_LEVEL1, "%s: compare %u -> %d \n",
419 				dev_name(&spi->dev), addr, status);
420 
421 		status = dataflash_waitready(priv->spi);
422 
423 		/* Check result of the compare operation */
424 		if (status & (1 << 6)) {
425 			printk(KERN_ERR "%s: compare page %u, err %d\n",
426 				dev_name(&spi->dev), pageaddr, status);
427 			remaining = 0;
428 			status = -EIO;
429 			break;
430 		} else
431 			status = 0;
432 
433 #endif	/* CONFIG_MTD_DATAFLASH_VERIFY_WRITE */
434 
435 		remaining = remaining - writelen;
436 		pageaddr++;
437 		offset = 0;
438 		writebuf += writelen;
439 		*retlen += writelen;
440 
441 		if (remaining > priv->page_size)
442 			writelen = priv->page_size;
443 		else
444 			writelen = remaining;
445 	}
446 	mutex_unlock(&priv->lock);
447 
448 	return status;
449 }
450 
451 /* ......................................................................... */
452 
453 #ifdef CONFIG_MTD_DATAFLASH_OTP
454 
455 static int dataflash_get_otp_info(struct mtd_info *mtd,
456 		struct otp_info *info, size_t len)
457 {
458 	/* Report both blocks as identical:  bytes 0..64, locked.
459 	 * Unless the user block changed from all-ones, we can't
460 	 * tell whether it's still writable; so we assume it isn't.
461 	 */
462 	info->start = 0;
463 	info->length = 64;
464 	info->locked = 1;
465 	return sizeof(*info);
466 }
467 
468 static ssize_t otp_read(struct spi_device *spi, unsigned base,
469 		uint8_t *buf, loff_t off, size_t len)
470 {
471 	struct spi_message	m;
472 	size_t			l;
473 	uint8_t			*scratch;
474 	struct spi_transfer	t;
475 	int			status;
476 
477 	if (off > 64)
478 		return -EINVAL;
479 
480 	if ((off + len) > 64)
481 		len = 64 - off;
482 	if (len == 0)
483 		return len;
484 
485 	spi_message_init(&m);
486 
487 	l = 4 + base + off + len;
488 	scratch = kzalloc(l, GFP_KERNEL);
489 	if (!scratch)
490 		return -ENOMEM;
491 
492 	/* OUT: OP_READ_SECURITY, 3 don't-care bytes, zeroes
493 	 * IN:  ignore 4 bytes, data bytes 0..N (max 127)
494 	 */
495 	scratch[0] = OP_READ_SECURITY;
496 
497 	memset(&t, 0, sizeof t);
498 	t.tx_buf = scratch;
499 	t.rx_buf = scratch;
500 	t.len = l;
501 	spi_message_add_tail(&t, &m);
502 
503 	dataflash_waitready(spi);
504 
505 	status = spi_sync(spi, &m);
506 	if (status >= 0) {
507 		memcpy(buf, scratch + 4 + base + off, len);
508 		status = len;
509 	}
510 
511 	kfree(scratch);
512 	return status;
513 }
514 
515 static int dataflash_read_fact_otp(struct mtd_info *mtd,
516 		loff_t from, size_t len, size_t *retlen, u_char *buf)
517 {
518 	struct dataflash	*priv = (struct dataflash *)mtd->priv;
519 	int			status;
520 
521 	/* 64 bytes, from 0..63 ... start at 64 on-chip */
522 	mutex_lock(&priv->lock);
523 	status = otp_read(priv->spi, 64, buf, from, len);
524 	mutex_unlock(&priv->lock);
525 
526 	if (status < 0)
527 		return status;
528 	*retlen = status;
529 	return 0;
530 }
531 
532 static int dataflash_read_user_otp(struct mtd_info *mtd,
533 		loff_t from, size_t len, size_t *retlen, u_char *buf)
534 {
535 	struct dataflash	*priv = (struct dataflash *)mtd->priv;
536 	int			status;
537 
538 	/* 64 bytes, from 0..63 ... start at 0 on-chip */
539 	mutex_lock(&priv->lock);
540 	status = otp_read(priv->spi, 0, buf, from, len);
541 	mutex_unlock(&priv->lock);
542 
543 	if (status < 0)
544 		return status;
545 	*retlen = status;
546 	return 0;
547 }
548 
549 static int dataflash_write_user_otp(struct mtd_info *mtd,
550 		loff_t from, size_t len, size_t *retlen, u_char *buf)
551 {
552 	struct spi_message	m;
553 	const size_t		l = 4 + 64;
554 	uint8_t			*scratch;
555 	struct spi_transfer	t;
556 	struct dataflash	*priv = (struct dataflash *)mtd->priv;
557 	int			status;
558 
559 	if (len > 64)
560 		return -EINVAL;
561 
562 	/* Strictly speaking, we *could* truncate the write ... but
563 	 * let's not do that for the only write that's ever possible.
564 	 */
565 	if ((from + len) > 64)
566 		return -EINVAL;
567 
568 	/* OUT: OP_WRITE_SECURITY, 3 zeroes, 64 data-or-zero bytes
569 	 * IN:  ignore all
570 	 */
571 	scratch = kzalloc(l, GFP_KERNEL);
572 	if (!scratch)
573 		return -ENOMEM;
574 	scratch[0] = OP_WRITE_SECURITY;
575 	memcpy(scratch + 4 + from, buf, len);
576 
577 	spi_message_init(&m);
578 
579 	memset(&t, 0, sizeof t);
580 	t.tx_buf = scratch;
581 	t.len = l;
582 	spi_message_add_tail(&t, &m);
583 
584 	/* Write the OTP bits, if they've not yet been written.
585 	 * This modifies SRAM buffer1.
586 	 */
587 	mutex_lock(&priv->lock);
588 	dataflash_waitready(priv->spi);
589 	status = spi_sync(priv->spi, &m);
590 	mutex_unlock(&priv->lock);
591 
592 	kfree(scratch);
593 
594 	if (status >= 0) {
595 		status = 0;
596 		*retlen = len;
597 	}
598 	return status;
599 }
600 
601 static char *otp_setup(struct mtd_info *device, char revision)
602 {
603 	device->get_fact_prot_info = dataflash_get_otp_info;
604 	device->read_fact_prot_reg = dataflash_read_fact_otp;
605 	device->get_user_prot_info = dataflash_get_otp_info;
606 	device->read_user_prot_reg = dataflash_read_user_otp;
607 
608 	/* rev c parts (at45db321c and at45db1281 only!) use a
609 	 * different write procedure; not (yet?) implemented.
610 	 */
611 	if (revision > 'c')
612 		device->write_user_prot_reg = dataflash_write_user_otp;
613 
614 	return ", OTP";
615 }
616 
617 #else
618 
619 static char *otp_setup(struct mtd_info *device, char revision)
620 {
621 	return " (OTP)";
622 }
623 
624 #endif
625 
626 /* ......................................................................... */
627 
628 /*
629  * Register DataFlash device with MTD subsystem.
630  */
631 static int __devinit
632 add_dataflash_otp(struct spi_device *spi, char *name,
633 		int nr_pages, int pagesize, int pageoffset, char revision)
634 {
635 	struct dataflash		*priv;
636 	struct mtd_info			*device;
637 	struct flash_platform_data	*pdata = spi->dev.platform_data;
638 	char				*otp_tag = "";
639 
640 	priv = kzalloc(sizeof *priv, GFP_KERNEL);
641 	if (!priv)
642 		return -ENOMEM;
643 
644 	mutex_init(&priv->lock);
645 	priv->spi = spi;
646 	priv->page_size = pagesize;
647 	priv->page_offset = pageoffset;
648 
649 	/* name must be usable with cmdlinepart */
650 	sprintf(priv->name, "spi%d.%d-%s",
651 			spi->master->bus_num, spi->chip_select,
652 			name);
653 
654 	device = &priv->mtd;
655 	device->name = (pdata && pdata->name) ? pdata->name : priv->name;
656 	device->size = nr_pages * pagesize;
657 	device->erasesize = pagesize;
658 	device->writesize = pagesize;
659 	device->owner = THIS_MODULE;
660 	device->type = MTD_DATAFLASH;
661 	device->flags = MTD_WRITEABLE;
662 	device->erase = dataflash_erase;
663 	device->read = dataflash_read;
664 	device->write = dataflash_write;
665 	device->priv = priv;
666 
667 	device->dev.parent = &spi->dev;
668 
669 	if (revision >= 'c')
670 		otp_tag = otp_setup(device, revision);
671 
672 	dev_info(&spi->dev, "%s (%lld KBytes) pagesize %d bytes%s\n",
673 			name, (long long)((device->size + 1023) >> 10),
674 			pagesize, otp_tag);
675 	dev_set_drvdata(&spi->dev, priv);
676 
677 	if (mtd_has_partitions()) {
678 		struct mtd_partition	*parts;
679 		int			nr_parts = 0;
680 
681 		if (mtd_has_cmdlinepart()) {
682 			static const char *part_probes[]
683 					= { "cmdlinepart", NULL, };
684 
685 			nr_parts = parse_mtd_partitions(device,
686 					part_probes, &parts, 0);
687 		}
688 
689 		if (nr_parts <= 0 && pdata && pdata->parts) {
690 			parts = pdata->parts;
691 			nr_parts = pdata->nr_parts;
692 		}
693 
694 		if (nr_parts > 0) {
695 			priv->partitioned = 1;
696 			return add_mtd_partitions(device, parts, nr_parts);
697 		}
698 	} else if (pdata && pdata->nr_parts)
699 		dev_warn(&spi->dev, "ignoring %d default partitions on %s\n",
700 				pdata->nr_parts, device->name);
701 
702 	return add_mtd_device(device) == 1 ? -ENODEV : 0;
703 }
704 
705 static inline int __devinit
706 add_dataflash(struct spi_device *spi, char *name,
707 		int nr_pages, int pagesize, int pageoffset)
708 {
709 	return add_dataflash_otp(spi, name, nr_pages, pagesize,
710 			pageoffset, 0);
711 }
712 
713 struct flash_info {
714 	char		*name;
715 
716 	/* JEDEC id has a high byte of zero plus three data bytes:
717 	 * the manufacturer id, then a two byte device id.
718 	 */
719 	uint32_t	jedec_id;
720 
721 	/* The size listed here is what works with OP_ERASE_PAGE. */
722 	unsigned	nr_pages;
723 	uint16_t	pagesize;
724 	uint16_t	pageoffset;
725 
726 	uint16_t	flags;
727 #define SUP_POW2PS	0x0002		/* supports 2^N byte pages */
728 #define IS_POW2PS	0x0001		/* uses 2^N byte pages */
729 };
730 
731 static struct flash_info __devinitdata dataflash_data [] = {
732 
733 	/*
734 	 * NOTE:  chips with SUP_POW2PS (rev D and up) need two entries,
735 	 * one with IS_POW2PS and the other without.  The entry with the
736 	 * non-2^N byte page size can't name exact chip revisions without
737 	 * losing backwards compatibility for cmdlinepart.
738 	 *
739 	 * These newer chips also support 128-byte security registers (with
740 	 * 64 bytes one-time-programmable) and software write-protection.
741 	 */
742 	{ "AT45DB011B",  0x1f2200, 512, 264, 9, SUP_POW2PS},
743 	{ "at45db011d",  0x1f2200, 512, 256, 8, SUP_POW2PS | IS_POW2PS},
744 
745 	{ "AT45DB021B",  0x1f2300, 1024, 264, 9, SUP_POW2PS},
746 	{ "at45db021d",  0x1f2300, 1024, 256, 8, SUP_POW2PS | IS_POW2PS},
747 
748 	{ "AT45DB041x",  0x1f2400, 2048, 264, 9, SUP_POW2PS},
749 	{ "at45db041d",  0x1f2400, 2048, 256, 8, SUP_POW2PS | IS_POW2PS},
750 
751 	{ "AT45DB081B",  0x1f2500, 4096, 264, 9, SUP_POW2PS},
752 	{ "at45db081d",  0x1f2500, 4096, 256, 8, SUP_POW2PS | IS_POW2PS},
753 
754 	{ "AT45DB161x",  0x1f2600, 4096, 528, 10, SUP_POW2PS},
755 	{ "at45db161d",  0x1f2600, 4096, 512, 9, SUP_POW2PS | IS_POW2PS},
756 
757 	{ "AT45DB321x",  0x1f2700, 8192, 528, 10, 0},		/* rev C */
758 
759 	{ "AT45DB321x",  0x1f2701, 8192, 528, 10, SUP_POW2PS},
760 	{ "at45db321d",  0x1f2701, 8192, 512, 9, SUP_POW2PS | IS_POW2PS},
761 
762 	{ "AT45DB642x",  0x1f2800, 8192, 1056, 11, SUP_POW2PS},
763 	{ "at45db642d",  0x1f2800, 8192, 1024, 10, SUP_POW2PS | IS_POW2PS},
764 };
765 
766 static struct flash_info *__devinit jedec_probe(struct spi_device *spi)
767 {
768 	int			tmp;
769 	uint8_t			code = OP_READ_ID;
770 	uint8_t			id[3];
771 	uint32_t		jedec;
772 	struct flash_info	*info;
773 	int status;
774 
775 	/* JEDEC also defines an optional "extended device information"
776 	 * string for after vendor-specific data, after the three bytes
777 	 * we use here.  Supporting some chips might require using it.
778 	 *
779 	 * If the vendor ID isn't Atmel's (0x1f), assume this call failed.
780 	 * That's not an error; only rev C and newer chips handle it, and
781 	 * only Atmel sells these chips.
782 	 */
783 	tmp = spi_write_then_read(spi, &code, 1, id, 3);
784 	if (tmp < 0) {
785 		DEBUG(MTD_DEBUG_LEVEL0, "%s: error %d reading JEDEC ID\n",
786 			dev_name(&spi->dev), tmp);
787 		return ERR_PTR(tmp);
788 	}
789 	if (id[0] != 0x1f)
790 		return NULL;
791 
792 	jedec = id[0];
793 	jedec = jedec << 8;
794 	jedec |= id[1];
795 	jedec = jedec << 8;
796 	jedec |= id[2];
797 
798 	for (tmp = 0, info = dataflash_data;
799 			tmp < ARRAY_SIZE(dataflash_data);
800 			tmp++, info++) {
801 		if (info->jedec_id == jedec) {
802 			DEBUG(MTD_DEBUG_LEVEL1, "%s: OTP, sector protect%s\n",
803 				dev_name(&spi->dev),
804 				(info->flags & SUP_POW2PS)
805 					? ", binary pagesize" : ""
806 				);
807 			if (info->flags & SUP_POW2PS) {
808 				status = dataflash_status(spi);
809 				if (status < 0) {
810 					DEBUG(MTD_DEBUG_LEVEL1,
811 						"%s: status error %d\n",
812 						dev_name(&spi->dev), status);
813 					return ERR_PTR(status);
814 				}
815 				if (status & 0x1) {
816 					if (info->flags & IS_POW2PS)
817 						return info;
818 				} else {
819 					if (!(info->flags & IS_POW2PS))
820 						return info;
821 				}
822 			} else
823 				return info;
824 		}
825 	}
826 
827 	/*
828 	 * Treat other chips as errors ... we won't know the right page
829 	 * size (it might be binary) even when we can tell which density
830 	 * class is involved (legacy chip id scheme).
831 	 */
832 	dev_warn(&spi->dev, "JEDEC id %06x not handled\n", jedec);
833 	return ERR_PTR(-ENODEV);
834 }
835 
836 /*
837  * Detect and initialize DataFlash device, using JEDEC IDs on newer chips
838  * or else the ID code embedded in the status bits:
839  *
840  *   Device      Density         ID code          #Pages PageSize  Offset
841  *   AT45DB011B  1Mbit   (128K)  xx0011xx (0x0c)    512    264      9
842  *   AT45DB021B  2Mbit   (256K)  xx0101xx (0x14)   1024    264      9
843  *   AT45DB041B  4Mbit   (512K)  xx0111xx (0x1c)   2048    264      9
844  *   AT45DB081B  8Mbit   (1M)    xx1001xx (0x24)   4096    264      9
845  *   AT45DB0161B 16Mbit  (2M)    xx1011xx (0x2c)   4096    528     10
846  *   AT45DB0321B 32Mbit  (4M)    xx1101xx (0x34)   8192    528     10
847  *   AT45DB0642  64Mbit  (8M)    xx111xxx (0x3c)   8192   1056     11
848  *   AT45DB1282  128Mbit (16M)   xx0100xx (0x10)  16384   1056     11
849  */
850 static int __devinit dataflash_probe(struct spi_device *spi)
851 {
852 	int status;
853 	struct flash_info	*info;
854 
855 	/*
856 	 * Try to detect dataflash by JEDEC ID.
857 	 * If it succeeds we know we have either a C or D part.
858 	 * D will support power of 2 pagesize option.
859 	 * Both support the security register, though with different
860 	 * write procedures.
861 	 */
862 	info = jedec_probe(spi);
863 	if (IS_ERR(info))
864 		return PTR_ERR(info);
865 	if (info != NULL)
866 		return add_dataflash_otp(spi, info->name, info->nr_pages,
867 				info->pagesize, info->pageoffset,
868 				(info->flags & SUP_POW2PS) ? 'd' : 'c');
869 
870 	/*
871 	 * Older chips support only legacy commands, identifing
872 	 * capacity using bits in the status byte.
873 	 */
874 	status = dataflash_status(spi);
875 	if (status <= 0 || status == 0xff) {
876 		DEBUG(MTD_DEBUG_LEVEL1, "%s: status error %d\n",
877 				dev_name(&spi->dev), status);
878 		if (status == 0 || status == 0xff)
879 			status = -ENODEV;
880 		return status;
881 	}
882 
883 	/* if there's a device there, assume it's dataflash.
884 	 * board setup should have set spi->max_speed_max to
885 	 * match f(car) for continuous reads, mode 0 or 3.
886 	 */
887 	switch (status & 0x3c) {
888 	case 0x0c:	/* 0 0 1 1 x x */
889 		status = add_dataflash(spi, "AT45DB011B", 512, 264, 9);
890 		break;
891 	case 0x14:	/* 0 1 0 1 x x */
892 		status = add_dataflash(spi, "AT45DB021B", 1024, 264, 9);
893 		break;
894 	case 0x1c:	/* 0 1 1 1 x x */
895 		status = add_dataflash(spi, "AT45DB041x", 2048, 264, 9);
896 		break;
897 	case 0x24:	/* 1 0 0 1 x x */
898 		status = add_dataflash(spi, "AT45DB081B", 4096, 264, 9);
899 		break;
900 	case 0x2c:	/* 1 0 1 1 x x */
901 		status = add_dataflash(spi, "AT45DB161x", 4096, 528, 10);
902 		break;
903 	case 0x34:	/* 1 1 0 1 x x */
904 		status = add_dataflash(spi, "AT45DB321x", 8192, 528, 10);
905 		break;
906 	case 0x38:	/* 1 1 1 x x x */
907 	case 0x3c:
908 		status = add_dataflash(spi, "AT45DB642x", 8192, 1056, 11);
909 		break;
910 	/* obsolete AT45DB1282 not (yet?) supported */
911 	default:
912 		DEBUG(MTD_DEBUG_LEVEL1, "%s: unsupported device (%x)\n",
913 				dev_name(&spi->dev), status & 0x3c);
914 		status = -ENODEV;
915 	}
916 
917 	if (status < 0)
918 		DEBUG(MTD_DEBUG_LEVEL1, "%s: add_dataflash --> %d\n",
919 				dev_name(&spi->dev), status);
920 
921 	return status;
922 }
923 
924 static int __devexit dataflash_remove(struct spi_device *spi)
925 {
926 	struct dataflash	*flash = dev_get_drvdata(&spi->dev);
927 	int			status;
928 
929 	DEBUG(MTD_DEBUG_LEVEL1, "%s: remove\n", dev_name(&spi->dev));
930 
931 	if (mtd_has_partitions() && flash->partitioned)
932 		status = del_mtd_partitions(&flash->mtd);
933 	else
934 		status = del_mtd_device(&flash->mtd);
935 	if (status == 0)
936 		kfree(flash);
937 	return status;
938 }
939 
940 static struct spi_driver dataflash_driver = {
941 	.driver = {
942 		.name		= "mtd_dataflash",
943 		.bus		= &spi_bus_type,
944 		.owner		= THIS_MODULE,
945 	},
946 
947 	.probe		= dataflash_probe,
948 	.remove		= __devexit_p(dataflash_remove),
949 
950 	/* FIXME:  investigate suspend and resume... */
951 };
952 
953 static int __init dataflash_init(void)
954 {
955 	return spi_register_driver(&dataflash_driver);
956 }
957 module_init(dataflash_init);
958 
959 static void __exit dataflash_exit(void)
960 {
961 	spi_unregister_driver(&dataflash_driver);
962 }
963 module_exit(dataflash_exit);
964 
965 
966 MODULE_LICENSE("GPL");
967 MODULE_AUTHOR("Andrew Victor, David Brownell");
968 MODULE_DESCRIPTION("MTD DataFlash driver");
969