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/spi/spi.h>
19 #include <linux/spi/flash.h>
20 
21 #include <linux/mtd/mtd.h>
22 #include <linux/mtd/partitions.h>
23 
24 
25 /*
26  * DataFlash is a kind of SPI flash.  Most AT45 chips have two buffers in
27  * each chip, which may be used for double buffered I/O; but this driver
28  * doesn't (yet) use these for any kind of i/o overlap or prefetching.
29  *
30  * Sometimes DataFlash is packaged in MMC-format cards, although the
31  * MMC stack can't use SPI (yet), or distinguish between MMC and DataFlash
32  * protocols during enumeration.
33  */
34 
35 #define CONFIG_DATAFLASH_WRITE_VERIFY
36 
37 /* reads can bypass the buffers */
38 #define OP_READ_CONTINUOUS	0xE8
39 #define OP_READ_PAGE		0xD2
40 
41 /* group B requests can run even while status reports "busy" */
42 #define OP_READ_STATUS		0xD7	/* group B */
43 
44 /* move data between host and buffer */
45 #define OP_READ_BUFFER1		0xD4	/* group B */
46 #define OP_READ_BUFFER2		0xD6	/* group B */
47 #define OP_WRITE_BUFFER1	0x84	/* group B */
48 #define OP_WRITE_BUFFER2	0x87	/* group B */
49 
50 /* erasing flash */
51 #define OP_ERASE_PAGE		0x81
52 #define OP_ERASE_BLOCK		0x50
53 
54 /* move data between buffer and flash */
55 #define OP_TRANSFER_BUF1	0x53
56 #define OP_TRANSFER_BUF2	0x55
57 #define OP_MREAD_BUFFER1	0xD4
58 #define OP_MREAD_BUFFER2	0xD6
59 #define OP_MWERASE_BUFFER1	0x83
60 #define OP_MWERASE_BUFFER2	0x86
61 #define OP_MWRITE_BUFFER1	0x88	/* sector must be pre-erased */
62 #define OP_MWRITE_BUFFER2	0x89	/* sector must be pre-erased */
63 
64 /* write to buffer, then write-erase to flash */
65 #define OP_PROGRAM_VIA_BUF1	0x82
66 #define OP_PROGRAM_VIA_BUF2	0x85
67 
68 /* compare buffer to flash */
69 #define OP_COMPARE_BUF1		0x60
70 #define OP_COMPARE_BUF2		0x61
71 
72 /* read flash to buffer, then write-erase to flash */
73 #define OP_REWRITE_VIA_BUF1	0x58
74 #define OP_REWRITE_VIA_BUF2	0x59
75 
76 /* newer chips report JEDEC manufacturer and device IDs; chip
77  * serial number and OTP bits; and per-sector writeprotect.
78  */
79 #define OP_READ_ID		0x9F
80 #define OP_READ_SECURITY	0x77
81 #define OP_WRITE_SECURITY	0x9A	/* OTP bits */
82 
83 
84 struct dataflash {
85 	uint8_t			command[4];
86 	char			name[24];
87 
88 	unsigned		partitioned:1;
89 
90 	unsigned short		page_offset;	/* offset in flash address */
91 	unsigned int		page_size;	/* of bytes per page */
92 
93 	struct mutex		lock;
94 	struct spi_device	*spi;
95 
96 	struct mtd_info		mtd;
97 };
98 
99 #ifdef CONFIG_MTD_PARTITIONS
100 #define	mtd_has_partitions()	(1)
101 #else
102 #define	mtd_has_partitions()	(0)
103 #endif
104 
105 /* ......................................................................... */
106 
107 /*
108  * Return the status of the DataFlash device.
109  */
110 static inline int dataflash_status(struct spi_device *spi)
111 {
112 	/* NOTE:  at45db321c over 25 MHz wants to write
113 	 * a dummy byte after the opcode...
114 	 */
115 	return spi_w8r8(spi, OP_READ_STATUS);
116 }
117 
118 /*
119  * Poll the DataFlash device until it is READY.
120  * This usually takes 5-20 msec or so; more for sector erase.
121  */
122 static int dataflash_waitready(struct spi_device *spi)
123 {
124 	int	status;
125 
126 	for (;;) {
127 		status = dataflash_status(spi);
128 		if (status < 0) {
129 			DEBUG(MTD_DEBUG_LEVEL1, "%s: status %d?\n",
130 					spi->dev.bus_id, status);
131 			status = 0;
132 		}
133 
134 		if (status & (1 << 7))	/* RDY/nBSY */
135 			return status;
136 
137 		msleep(3);
138 	}
139 }
140 
141 /* ......................................................................... */
142 
143 /*
144  * Erase pages of flash.
145  */
146 static int dataflash_erase(struct mtd_info *mtd, struct erase_info *instr)
147 {
148 	struct dataflash	*priv = (struct dataflash *)mtd->priv;
149 	struct spi_device	*spi = priv->spi;
150 	struct spi_transfer	x = { .tx_dma = 0, };
151 	struct spi_message	msg;
152 	unsigned		blocksize = priv->page_size << 3;
153 	uint8_t			*command;
154 
155 	DEBUG(MTD_DEBUG_LEVEL2, "%s: erase addr=0x%x len 0x%x\n",
156 			spi->dev.bus_id,
157 			instr->addr, instr->len);
158 
159 	/* Sanity checks */
160 	if ((instr->addr + instr->len) > mtd->size
161 			|| (instr->len % priv->page_size) != 0
162 			|| (instr->addr % priv->page_size) != 0)
163 		return -EINVAL;
164 
165 	spi_message_init(&msg);
166 
167 	x.tx_buf = command = priv->command;
168 	x.len = 4;
169 	spi_message_add_tail(&x, &msg);
170 
171 	mutex_lock(&priv->lock);
172 	while (instr->len > 0) {
173 		unsigned int	pageaddr;
174 		int		status;
175 		int		do_block;
176 
177 		/* Calculate flash page address; use block erase (for speed) if
178 		 * we're at a block boundary and need to erase the whole block.
179 		 */
180 		pageaddr = instr->addr / priv->page_size;
181 		do_block = (pageaddr & 0x7) == 0 && instr->len >= blocksize;
182 		pageaddr = pageaddr << priv->page_offset;
183 
184 		command[0] = do_block ? OP_ERASE_BLOCK : OP_ERASE_PAGE;
185 		command[1] = (uint8_t)(pageaddr >> 16);
186 		command[2] = (uint8_t)(pageaddr >> 8);
187 		command[3] = 0;
188 
189 		DEBUG(MTD_DEBUG_LEVEL3, "ERASE %s: (%x) %x %x %x [%i]\n",
190 			do_block ? "block" : "page",
191 			command[0], command[1], command[2], command[3],
192 			pageaddr);
193 
194 		status = spi_sync(spi, &msg);
195 		(void) dataflash_waitready(spi);
196 
197 		if (status < 0) {
198 			printk(KERN_ERR "%s: erase %x, err %d\n",
199 				spi->dev.bus_id, pageaddr, status);
200 			/* REVISIT:  can retry instr->retries times; or
201 			 * giveup and instr->fail_addr = instr->addr;
202 			 */
203 			continue;
204 		}
205 
206 		if (do_block) {
207 			instr->addr += blocksize;
208 			instr->len -= blocksize;
209 		} else {
210 			instr->addr += priv->page_size;
211 			instr->len -= priv->page_size;
212 		}
213 	}
214 	mutex_unlock(&priv->lock);
215 
216 	/* Inform MTD subsystem that erase is complete */
217 	instr->state = MTD_ERASE_DONE;
218 	mtd_erase_callback(instr);
219 
220 	return 0;
221 }
222 
223 /*
224  * Read from the DataFlash device.
225  *   from   : Start offset in flash device
226  *   len    : Amount to read
227  *   retlen : About of data actually read
228  *   buf    : Buffer containing the data
229  */
230 static int dataflash_read(struct mtd_info *mtd, loff_t from, size_t len,
231 			       size_t *retlen, u_char *buf)
232 {
233 	struct dataflash	*priv = (struct dataflash *)mtd->priv;
234 	struct spi_transfer	x[2] = { { .tx_dma = 0, }, };
235 	struct spi_message	msg;
236 	unsigned int		addr;
237 	uint8_t			*command;
238 	int			status;
239 
240 	DEBUG(MTD_DEBUG_LEVEL2, "%s: read 0x%x..0x%x\n",
241 		priv->spi->dev.bus_id, (unsigned)from, (unsigned)(from + len));
242 
243 	*retlen = 0;
244 
245 	/* Sanity checks */
246 	if (!len)
247 		return 0;
248 	if (from + len > mtd->size)
249 		return -EINVAL;
250 
251 	/* Calculate flash page/byte address */
252 	addr = (((unsigned)from / priv->page_size) << priv->page_offset)
253 		+ ((unsigned)from % priv->page_size);
254 
255 	command = priv->command;
256 
257 	DEBUG(MTD_DEBUG_LEVEL3, "READ: (%x) %x %x %x\n",
258 		command[0], command[1], command[2], command[3]);
259 
260 	spi_message_init(&msg);
261 
262 	x[0].tx_buf = command;
263 	x[0].len = 8;
264 	spi_message_add_tail(&x[0], &msg);
265 
266 	x[1].rx_buf = buf;
267 	x[1].len = len;
268 	spi_message_add_tail(&x[1], &msg);
269 
270 	mutex_lock(&priv->lock);
271 
272 	/* Continuous read, max clock = f(car) which may be less than
273 	 * the peak rate available.  Some chips support commands with
274 	 * fewer "don't care" bytes.  Both buffers stay unchanged.
275 	 */
276 	command[0] = OP_READ_CONTINUOUS;
277 	command[1] = (uint8_t)(addr >> 16);
278 	command[2] = (uint8_t)(addr >> 8);
279 	command[3] = (uint8_t)(addr >> 0);
280 	/* plus 4 "don't care" bytes */
281 
282 	status = spi_sync(priv->spi, &msg);
283 	mutex_unlock(&priv->lock);
284 
285 	if (status >= 0) {
286 		*retlen = msg.actual_length - 8;
287 		status = 0;
288 	} else
289 		DEBUG(MTD_DEBUG_LEVEL1, "%s: read %x..%x --> %d\n",
290 			priv->spi->dev.bus_id,
291 			(unsigned)from, (unsigned)(from + len),
292 			status);
293 	return status;
294 }
295 
296 /*
297  * Write to the DataFlash device.
298  *   to     : Start offset in flash device
299  *   len    : Amount to write
300  *   retlen : Amount of data actually written
301  *   buf    : Buffer containing the data
302  */
303 static int dataflash_write(struct mtd_info *mtd, loff_t to, size_t len,
304 				size_t * retlen, const u_char * buf)
305 {
306 	struct dataflash	*priv = (struct dataflash *)mtd->priv;
307 	struct spi_device	*spi = priv->spi;
308 	struct spi_transfer	x[2] = { { .tx_dma = 0, }, };
309 	struct spi_message	msg;
310 	unsigned int		pageaddr, addr, offset, writelen;
311 	size_t			remaining = len;
312 	u_char			*writebuf = (u_char *) buf;
313 	int			status = -EINVAL;
314 	uint8_t			*command;
315 
316 	DEBUG(MTD_DEBUG_LEVEL2, "%s: write 0x%x..0x%x\n",
317 		spi->dev.bus_id, (unsigned)to, (unsigned)(to + len));
318 
319 	*retlen = 0;
320 
321 	/* Sanity checks */
322 	if (!len)
323 		return 0;
324 	if ((to + len) > mtd->size)
325 		return -EINVAL;
326 
327 	spi_message_init(&msg);
328 
329 	x[0].tx_buf = command = priv->command;
330 	x[0].len = 4;
331 	spi_message_add_tail(&x[0], &msg);
332 
333 	pageaddr = ((unsigned)to / priv->page_size);
334 	offset = ((unsigned)to % priv->page_size);
335 	if (offset + len > priv->page_size)
336 		writelen = priv->page_size - offset;
337 	else
338 		writelen = len;
339 
340 	mutex_lock(&priv->lock);
341 	while (remaining > 0) {
342 		DEBUG(MTD_DEBUG_LEVEL3, "write @ %i:%i len=%i\n",
343 			pageaddr, offset, writelen);
344 
345 		/* REVISIT:
346 		 * (a) each page in a sector must be rewritten at least
347 		 *     once every 10K sibling erase/program operations.
348 		 * (b) for pages that are already erased, we could
349 		 *     use WRITE+MWRITE not PROGRAM for ~30% speedup.
350 		 * (c) WRITE to buffer could be done while waiting for
351 		 *     a previous MWRITE/MWERASE to complete ...
352 		 * (d) error handling here seems to be mostly missing.
353 		 *
354 		 * Two persistent bits per page, plus a per-sector counter,
355 		 * could support (a) and (b) ... we might consider using
356 		 * the second half of sector zero, which is just one block,
357 		 * to track that state.  (On AT91, that sector should also
358 		 * support boot-from-DataFlash.)
359 		 */
360 
361 		addr = pageaddr << priv->page_offset;
362 
363 		/* (1) Maybe transfer partial page to Buffer1 */
364 		if (writelen != priv->page_size) {
365 			command[0] = OP_TRANSFER_BUF1;
366 			command[1] = (addr & 0x00FF0000) >> 16;
367 			command[2] = (addr & 0x0000FF00) >> 8;
368 			command[3] = 0;
369 
370 			DEBUG(MTD_DEBUG_LEVEL3, "TRANSFER: (%x) %x %x %x\n",
371 				command[0], command[1], command[2], command[3]);
372 
373 			status = spi_sync(spi, &msg);
374 			if (status < 0)
375 				DEBUG(MTD_DEBUG_LEVEL1, "%s: xfer %u -> %d \n",
376 					spi->dev.bus_id, addr, status);
377 
378 			(void) dataflash_waitready(priv->spi);
379 		}
380 
381 		/* (2) Program full page via Buffer1 */
382 		addr += offset;
383 		command[0] = OP_PROGRAM_VIA_BUF1;
384 		command[1] = (addr & 0x00FF0000) >> 16;
385 		command[2] = (addr & 0x0000FF00) >> 8;
386 		command[3] = (addr & 0x000000FF);
387 
388 		DEBUG(MTD_DEBUG_LEVEL3, "PROGRAM: (%x) %x %x %x\n",
389 			command[0], command[1], command[2], command[3]);
390 
391 		x[1].tx_buf = writebuf;
392 		x[1].len = writelen;
393 		spi_message_add_tail(x + 1, &msg);
394 		status = spi_sync(spi, &msg);
395 		spi_transfer_del(x + 1);
396 		if (status < 0)
397 			DEBUG(MTD_DEBUG_LEVEL1, "%s: pgm %u/%u -> %d \n",
398 				spi->dev.bus_id, addr, writelen, status);
399 
400 		(void) dataflash_waitready(priv->spi);
401 
402 
403 #ifdef	CONFIG_DATAFLASH_WRITE_VERIFY
404 
405 		/* (3) Compare to Buffer1 */
406 		addr = pageaddr << priv->page_offset;
407 		command[0] = OP_COMPARE_BUF1;
408 		command[1] = (addr & 0x00FF0000) >> 16;
409 		command[2] = (addr & 0x0000FF00) >> 8;
410 		command[3] = 0;
411 
412 		DEBUG(MTD_DEBUG_LEVEL3, "COMPARE: (%x) %x %x %x\n",
413 			command[0], command[1], command[2], command[3]);
414 
415 		status = spi_sync(spi, &msg);
416 		if (status < 0)
417 			DEBUG(MTD_DEBUG_LEVEL1, "%s: compare %u -> %d \n",
418 				spi->dev.bus_id, addr, status);
419 
420 		status = dataflash_waitready(priv->spi);
421 
422 		/* Check result of the compare operation */
423 		if (status & (1 << 6)) {
424 			printk(KERN_ERR "%s: compare page %u, err %d\n",
425 				spi->dev.bus_id, pageaddr, status);
426 			remaining = 0;
427 			status = -EIO;
428 			break;
429 		} else
430 			status = 0;
431 
432 #endif	/* CONFIG_DATAFLASH_WRITE_VERIFY */
433 
434 		remaining = remaining - writelen;
435 		pageaddr++;
436 		offset = 0;
437 		writebuf += writelen;
438 		*retlen += writelen;
439 
440 		if (remaining > priv->page_size)
441 			writelen = priv->page_size;
442 		else
443 			writelen = remaining;
444 	}
445 	mutex_unlock(&priv->lock);
446 
447 	return status;
448 }
449 
450 /* ......................................................................... */
451 
452 /*
453  * Register DataFlash device with MTD subsystem.
454  */
455 static int __devinit
456 add_dataflash(struct spi_device *spi, char *name,
457 		int nr_pages, int pagesize, int pageoffset)
458 {
459 	struct dataflash		*priv;
460 	struct mtd_info			*device;
461 	struct flash_platform_data	*pdata = spi->dev.platform_data;
462 
463 	priv = kzalloc(sizeof *priv, GFP_KERNEL);
464 	if (!priv)
465 		return -ENOMEM;
466 
467 	mutex_init(&priv->lock);
468 	priv->spi = spi;
469 	priv->page_size = pagesize;
470 	priv->page_offset = pageoffset;
471 
472 	/* name must be usable with cmdlinepart */
473 	sprintf(priv->name, "spi%d.%d-%s",
474 			spi->master->bus_num, spi->chip_select,
475 			name);
476 
477 	device = &priv->mtd;
478 	device->name = (pdata && pdata->name) ? pdata->name : priv->name;
479 	device->size = nr_pages * pagesize;
480 	device->erasesize = pagesize;
481 	device->writesize = pagesize;
482 	device->owner = THIS_MODULE;
483 	device->type = MTD_DATAFLASH;
484 	device->flags = MTD_WRITEABLE;
485 	device->erase = dataflash_erase;
486 	device->read = dataflash_read;
487 	device->write = dataflash_write;
488 	device->priv = priv;
489 
490 	dev_info(&spi->dev, "%s (%d KBytes) pagesize %d bytes, "
491 		"erasesize %d bytes\n", name, device->size/1024,
492 		 pagesize, pagesize * 8);	/* 8 pages = 1 block */
493 	dev_set_drvdata(&spi->dev, priv);
494 
495 	if (mtd_has_partitions()) {
496 		struct mtd_partition	*parts;
497 		int			nr_parts = 0;
498 
499 #ifdef CONFIG_MTD_CMDLINE_PARTS
500 		static const char *part_probes[] = { "cmdlinepart", NULL, };
501 
502 		nr_parts = parse_mtd_partitions(device, part_probes, &parts, 0);
503 #endif
504 
505 		if (nr_parts <= 0 && pdata && pdata->parts) {
506 			parts = pdata->parts;
507 			nr_parts = pdata->nr_parts;
508 		}
509 
510 		if (nr_parts > 0) {
511 			priv->partitioned = 1;
512 			return add_mtd_partitions(device, parts, nr_parts);
513 		}
514 	} else if (pdata && pdata->nr_parts)
515 		dev_warn(&spi->dev, "ignoring %d default partitions on %s\n",
516 				pdata->nr_parts, device->name);
517 
518 	return add_mtd_device(device) == 1 ? -ENODEV : 0;
519 }
520 
521 /*
522  * Detect and initialize DataFlash device:
523  *
524  *   Device      Density         ID code          #Pages PageSize  Offset
525  *   AT45DB011B  1Mbit   (128K)  xx0011xx (0x0c)    512    264      9
526  *   AT45DB021B  2Mbit   (256K)  xx0101xx (0x14)   1024    264      9
527  *   AT45DB041B  4Mbit   (512K)  xx0111xx (0x1c)   2048    264      9
528  *   AT45DB081B  8Mbit   (1M)    xx1001xx (0x24)   4096    264      9
529  *   AT45DB0161B 16Mbit  (2M)    xx1011xx (0x2c)   4096    528     10
530  *   AT45DB0321B 32Mbit  (4M)    xx1101xx (0x34)   8192    528     10
531  *   AT45DB0642  64Mbit  (8M)    xx111xxx (0x3c)   8192   1056     11
532  *   AT45DB1282  128Mbit (16M)   xx0100xx (0x10)  16384   1056     11
533  */
534 
535 struct flash_info {
536 	char		*name;
537 
538 	/* JEDEC id zero means "no ID" (most older chips); otherwise it has
539 	 * a high byte of zero plus three data bytes: the manufacturer id,
540 	 * then a two byte device id.
541 	 */
542 	uint32_t	jedec_id;
543 
544 	/* The size listed here is what works with OPCODE_SE, which isn't
545 	 * necessarily called a "sector" by the vendor.
546 	 */
547 	unsigned	nr_pages;
548 	uint16_t	pagesize;
549 	uint16_t	pageoffset;
550 
551 	uint16_t	flags;
552 #define	SUP_POW2PS	0x02
553 #define	IS_POW2PS	0x01
554 };
555 
556 static struct flash_info __devinitdata dataflash_data [] = {
557 
558 	{ "at45db011d",  0x1f2200, 512, 264, 9, SUP_POW2PS},
559 	{ "at45db011d",  0x1f2200, 512, 256, 8, SUP_POW2PS | IS_POW2PS},
560 
561 	{ "at45db021d",  0x1f2300, 1024, 264, 9, SUP_POW2PS},
562 	{ "at45db021d",  0x1f2300, 1024, 256, 8, SUP_POW2PS | IS_POW2PS},
563 
564 	{ "at45db041d",  0x1f2400, 2048, 264, 9, SUP_POW2PS},
565 	{ "at45db041d",  0x1f2400, 2048, 256, 8, SUP_POW2PS | IS_POW2PS},
566 
567 	{ "at45db081d",  0x1f2500, 4096, 264, 9, SUP_POW2PS},
568 	{ "at45db081d",  0x1f2500, 4096, 256, 8, SUP_POW2PS | IS_POW2PS},
569 
570 	{ "at45db161d",  0x1f2600, 4096, 528, 10, SUP_POW2PS},
571 	{ "at45db161d",  0x1f2600, 4096, 512, 9, SUP_POW2PS | IS_POW2PS},
572 
573 	{ "at45db321c",  0x1f2700, 8192, 528, 10, },
574 
575 	{ "at45db321d",  0x1f2701, 8192, 528, 10, SUP_POW2PS},
576 	{ "at45db321d",  0x1f2701, 8192, 512, 9, SUP_POW2PS | IS_POW2PS},
577 
578 	{ "at45db641d",  0x1f2800, 8192, 1056, 11, SUP_POW2PS},
579 	{ "at45db641d",  0x1f2800, 8192, 1024, 10, SUP_POW2PS | IS_POW2PS},
580 };
581 
582 static struct flash_info *__devinit jedec_probe(struct spi_device *spi)
583 {
584 	int			tmp;
585 	uint8_t			code = OP_READ_ID;
586 	uint8_t			id[3];
587 	uint32_t		jedec;
588 	struct flash_info	*info;
589 	int status;
590 
591 
592 	/* JEDEC also defines an optional "extended device information"
593 	 * string for after vendor-specific data, after the three bytes
594 	 * we use here.  Supporting some chips might require using it.
595 	 */
596 	tmp = spi_write_then_read(spi, &code, 1, id, 3);
597 	if (tmp < 0) {
598 		DEBUG(MTD_DEBUG_LEVEL0, "%s: error %d reading JEDEC ID\n",
599 			spi->dev.bus_id, tmp);
600 		return NULL;
601 	}
602 	jedec = id[0];
603 	jedec = jedec << 8;
604 	jedec |= id[1];
605 	jedec = jedec << 8;
606 	jedec |= id[2];
607 
608 	for (tmp = 0, info = dataflash_data;
609 			tmp < ARRAY_SIZE(dataflash_data);
610 			tmp++, info++) {
611 		if (info->jedec_id == jedec) {
612 			if (info->flags & SUP_POW2PS) {
613 				status = dataflash_status(spi);
614 				if (status & 0x1)
615 					/* return power of 2 pagesize */
616 					return ++info;
617 				else
618 					return info;
619 			}
620 		}
621 	}
622 	return NULL;
623 }
624 
625 static int __devinit dataflash_probe(struct spi_device *spi)
626 {
627 	int status;
628 	struct flash_info	*info;
629 
630 	/*
631 	 * Try to detect dataflash by JEDEC ID.
632 	 * If it succeeds we know we have either a C or D part.
633 	 * D will support power of 2 pagesize option.
634 	 */
635 
636 	info = jedec_probe(spi);
637 
638 	if (info != NULL)
639 		return add_dataflash(spi, info->name, info->nr_pages,
640 				 info->pagesize, info->pageoffset);
641 
642 
643 	status = dataflash_status(spi);
644 	if (status <= 0 || status == 0xff) {
645 		DEBUG(MTD_DEBUG_LEVEL1, "%s: status error %d\n",
646 				spi->dev.bus_id, status);
647 		if (status == 0 || status == 0xff)
648 			status = -ENODEV;
649 		return status;
650 	}
651 
652 	/* if there's a device there, assume it's dataflash.
653 	 * board setup should have set spi->max_speed_max to
654 	 * match f(car) for continuous reads, mode 0 or 3.
655 	 */
656 	switch (status & 0x3c) {
657 	case 0x0c:	/* 0 0 1 1 x x */
658 		status = add_dataflash(spi, "AT45DB011B", 512, 264, 9);
659 		break;
660 	case 0x14:	/* 0 1 0 1 x x */
661 		status = add_dataflash(spi, "AT45DB021B", 1024, 264, 9);
662 		break;
663 	case 0x1c:	/* 0 1 1 1 x x */
664 		status = add_dataflash(spi, "AT45DB041B", 2048, 264, 9);
665 		break;
666 	case 0x24:	/* 1 0 0 1 x x */
667 		status = add_dataflash(spi, "AT45DB081B", 4096, 264, 9);
668 		break;
669 	case 0x2c:	/* 1 0 1 1 x x */
670 		status = add_dataflash(spi, "AT45DB161B", 4096, 528, 10);
671 		break;
672 	case 0x34:	/* 1 1 0 1 x x */
673 		status = add_dataflash(spi, "AT45DB321x", 8192, 528, 10);
674 		break;
675 	case 0x38:	/* 1 1 1 x x x */
676 	case 0x3c:
677 		status = add_dataflash(spi, "AT45DB642x", 8192, 1056, 11);
678 		break;
679 	/* obsolete AT45DB1282 not (yet?) supported */
680 	default:
681 		DEBUG(MTD_DEBUG_LEVEL1, "%s: unsupported device (%x)\n",
682 				spi->dev.bus_id, status & 0x3c);
683 		status = -ENODEV;
684 	}
685 
686 	if (status < 0)
687 		DEBUG(MTD_DEBUG_LEVEL1, "%s: add_dataflash --> %d\n",
688 				spi->dev.bus_id, status);
689 
690 	return status;
691 }
692 
693 static int __devexit dataflash_remove(struct spi_device *spi)
694 {
695 	struct dataflash	*flash = dev_get_drvdata(&spi->dev);
696 	int			status;
697 
698 	DEBUG(MTD_DEBUG_LEVEL1, "%s: remove\n", spi->dev.bus_id);
699 
700 	if (mtd_has_partitions() && flash->partitioned)
701 		status = del_mtd_partitions(&flash->mtd);
702 	else
703 		status = del_mtd_device(&flash->mtd);
704 	if (status == 0)
705 		kfree(flash);
706 	return status;
707 }
708 
709 static struct spi_driver dataflash_driver = {
710 	.driver = {
711 		.name		= "mtd_dataflash",
712 		.bus		= &spi_bus_type,
713 		.owner		= THIS_MODULE,
714 	},
715 
716 	.probe		= dataflash_probe,
717 	.remove		= __devexit_p(dataflash_remove),
718 
719 	/* FIXME:  investigate suspend and resume... */
720 };
721 
722 static int __init dataflash_init(void)
723 {
724 	return spi_register_driver(&dataflash_driver);
725 }
726 module_init(dataflash_init);
727 
728 static void __exit dataflash_exit(void)
729 {
730 	spi_unregister_driver(&dataflash_driver);
731 }
732 module_exit(dataflash_exit);
733 
734 
735 MODULE_LICENSE("GPL");
736 MODULE_AUTHOR("Andrew Victor, David Brownell");
737 MODULE_DESCRIPTION("MTD DataFlash driver");
738