xref: /linux/drivers/mtd/devices/docg3.c (revision 424f0750edd5af866f80f5e65998e0610503cb5c)
1 /*
2  * Handles the M-Systems DiskOnChip G3 chip
3  *
4  * Copyright (C) 2011 Robert Jarzmik
5  *
6  * This program is free software; you can redistribute it and/or modify
7  * it under the terms of the GNU General Public License as published by
8  * the Free Software Foundation; either version 2 of the License, or
9  * (at your option) any later version.
10  *
11  * This program is distributed in the hope that it will be useful,
12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
14  * GNU General Public License for more details.
15  *
16  * You should have received a copy of the GNU General Public License
17  * along with this program; if not, write to the Free Software
18  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
19  *
20  */
21 
22 #include <linux/kernel.h>
23 #include <linux/module.h>
24 #include <linux/errno.h>
25 #include <linux/platform_device.h>
26 #include <linux/string.h>
27 #include <linux/slab.h>
28 #include <linux/io.h>
29 #include <linux/delay.h>
30 #include <linux/mtd/mtd.h>
31 #include <linux/mtd/partitions.h>
32 
33 #include <linux/debugfs.h>
34 #include <linux/seq_file.h>
35 
36 #define CREATE_TRACE_POINTS
37 #include "docg3.h"
38 
39 /*
40  * This driver handles the DiskOnChip G3 flash memory.
41  *
42  * As no specification is available from M-Systems/Sandisk, this drivers lacks
43  * several functions available on the chip, as :
44  *  - block erase
45  *  - page write
46  *  - IPL write
47  *  - ECC fixing (lack of BCH algorith understanding)
48  *  - powerdown / powerup
49  *
50  * The bus data width (8bits versus 16bits) is not handled (if_cfg flag), and
51  * the driver assumes a 16bits data bus.
52  *
53  * DocG3 relies on 2 ECC algorithms, which are handled in hardware :
54  *  - a 1 byte Hamming code stored in the OOB for each page
55  *  - a 7 bytes BCH code stored in the OOB for each page
56  * The BCH part is only used for check purpose, no correction is available as
57  * some information is missing. What is known is that :
58  *  - BCH is in GF(2^14)
59  *  - BCH is over data of 520 bytes (512 page + 7 page_info bytes
60  *                                   + 1 hamming byte)
61  *  - BCH can correct up to 4 bits (t = 4)
62  *  - BCH syndroms are calculated in hardware, and checked in hardware as well
63  *
64  */
65 
66 static inline u8 doc_readb(struct docg3 *docg3, u16 reg)
67 {
68 	u8 val = readb(docg3->base + reg);
69 
70 	trace_docg3_io(0, 8, reg, (int)val);
71 	return val;
72 }
73 
74 static inline u16 doc_readw(struct docg3 *docg3, u16 reg)
75 {
76 	u16 val = readw(docg3->base + reg);
77 
78 	trace_docg3_io(0, 16, reg, (int)val);
79 	return val;
80 }
81 
82 static inline void doc_writeb(struct docg3 *docg3, u8 val, u16 reg)
83 {
84 	writeb(val, docg3->base + reg);
85 	trace_docg3_io(1, 16, reg, val);
86 }
87 
88 static inline void doc_writew(struct docg3 *docg3, u16 val, u16 reg)
89 {
90 	writew(val, docg3->base + reg);
91 	trace_docg3_io(1, 16, reg, val);
92 }
93 
94 static inline void doc_flash_command(struct docg3 *docg3, u8 cmd)
95 {
96 	doc_writeb(docg3, cmd, DOC_FLASHCOMMAND);
97 }
98 
99 static inline void doc_flash_sequence(struct docg3 *docg3, u8 seq)
100 {
101 	doc_writeb(docg3, seq, DOC_FLASHSEQUENCE);
102 }
103 
104 static inline void doc_flash_address(struct docg3 *docg3, u8 addr)
105 {
106 	doc_writeb(docg3, addr, DOC_FLASHADDRESS);
107 }
108 
109 static char const *part_probes[] = { "cmdlinepart", "saftlpart", NULL };
110 
111 static int doc_register_readb(struct docg3 *docg3, int reg)
112 {
113 	u8 val;
114 
115 	doc_writew(docg3, reg, DOC_READADDRESS);
116 	val = doc_readb(docg3, reg);
117 	doc_vdbg("Read register %04x : %02x\n", reg, val);
118 	return val;
119 }
120 
121 static int doc_register_readw(struct docg3 *docg3, int reg)
122 {
123 	u16 val;
124 
125 	doc_writew(docg3, reg, DOC_READADDRESS);
126 	val = doc_readw(docg3, reg);
127 	doc_vdbg("Read register %04x : %04x\n", reg, val);
128 	return val;
129 }
130 
131 /**
132  * doc_delay - delay docg3 operations
133  * @docg3: the device
134  * @nbNOPs: the number of NOPs to issue
135  *
136  * As no specification is available, the right timings between chip commands are
137  * unknown. The only available piece of information are the observed nops on a
138  * working docg3 chip.
139  * Therefore, doc_delay relies on a busy loop of NOPs, instead of scheduler
140  * friendlier msleep() functions or blocking mdelay().
141  */
142 static void doc_delay(struct docg3 *docg3, int nbNOPs)
143 {
144 	int i;
145 
146 	doc_dbg("NOP x %d\n", nbNOPs);
147 	for (i = 0; i < nbNOPs; i++)
148 		doc_writeb(docg3, 0, DOC_NOP);
149 }
150 
151 static int is_prot_seq_error(struct docg3 *docg3)
152 {
153 	int ctrl;
154 
155 	ctrl = doc_register_readb(docg3, DOC_FLASHCONTROL);
156 	return ctrl & (DOC_CTRL_PROTECTION_ERROR | DOC_CTRL_SEQUENCE_ERROR);
157 }
158 
159 static int doc_is_ready(struct docg3 *docg3)
160 {
161 	int ctrl;
162 
163 	ctrl = doc_register_readb(docg3, DOC_FLASHCONTROL);
164 	return ctrl & DOC_CTRL_FLASHREADY;
165 }
166 
167 static int doc_wait_ready(struct docg3 *docg3)
168 {
169 	int maxWaitCycles = 100;
170 
171 	do {
172 		doc_delay(docg3, 4);
173 		cpu_relax();
174 	} while (!doc_is_ready(docg3) && maxWaitCycles--);
175 	doc_delay(docg3, 2);
176 	if (maxWaitCycles > 0)
177 		return 0;
178 	else
179 		return -EIO;
180 }
181 
182 static int doc_reset_seq(struct docg3 *docg3)
183 {
184 	int ret;
185 
186 	doc_writeb(docg3, 0x10, DOC_FLASHCONTROL);
187 	doc_flash_sequence(docg3, DOC_SEQ_RESET);
188 	doc_flash_command(docg3, DOC_CMD_RESET);
189 	doc_delay(docg3, 2);
190 	ret = doc_wait_ready(docg3);
191 
192 	doc_dbg("doc_reset_seq() -> isReady=%s\n", ret ? "false" : "true");
193 	return ret;
194 }
195 
196 /**
197  * doc_read_data_area - Read data from data area
198  * @docg3: the device
199  * @buf: the buffer to fill in
200  * @len: the lenght to read
201  * @first: first time read, DOC_READADDRESS should be set
202  *
203  * Reads bytes from flash data. Handles the single byte / even bytes reads.
204  */
205 static void doc_read_data_area(struct docg3 *docg3, void *buf, int len,
206 			       int first)
207 {
208 	int i, cdr, len4;
209 	u16 data16, *dst16;
210 	u8 data8, *dst8;
211 
212 	doc_dbg("doc_read_data_area(buf=%p, len=%d)\n", buf, len);
213 	cdr = len & 0x3;
214 	len4 = len - cdr;
215 
216 	if (first)
217 		doc_writew(docg3, DOC_IOSPACE_DATA, DOC_READADDRESS);
218 	dst16 = buf;
219 	for (i = 0; i < len4; i += 2) {
220 		data16 = doc_readw(docg3, DOC_IOSPACE_DATA);
221 		*dst16 = data16;
222 		dst16++;
223 	}
224 
225 	if (cdr) {
226 		doc_writew(docg3, DOC_IOSPACE_DATA | DOC_READADDR_ONE_BYTE,
227 			   DOC_READADDRESS);
228 		doc_delay(docg3, 1);
229 		dst8 = (u8 *)dst16;
230 		for (i = 0; i < cdr; i++) {
231 			data8 = doc_readb(docg3, DOC_IOSPACE_DATA);
232 			*dst8 = data8;
233 			dst8++;
234 		}
235 	}
236 }
237 
238 /**
239  * doc_set_data_mode - Sets the flash to reliable data mode
240  * @docg3: the device
241  *
242  * The reliable data mode is a bit slower than the fast mode, but less errors
243  * occur.  Entering the reliable mode cannot be done without entering the fast
244  * mode first.
245  */
246 static void doc_set_reliable_mode(struct docg3 *docg3)
247 {
248 	doc_dbg("doc_set_reliable_mode()\n");
249 	doc_flash_sequence(docg3, DOC_SEQ_SET_MODE);
250 	doc_flash_command(docg3, DOC_CMD_FAST_MODE);
251 	doc_flash_command(docg3, DOC_CMD_RELIABLE_MODE);
252 	doc_delay(docg3, 2);
253 }
254 
255 /**
256  * doc_set_asic_mode - Set the ASIC mode
257  * @docg3: the device
258  * @mode: the mode
259  *
260  * The ASIC can work in 3 modes :
261  *  - RESET: all registers are zeroed
262  *  - NORMAL: receives and handles commands
263  *  - POWERDOWN: minimal poweruse, flash parts shut off
264  */
265 static void doc_set_asic_mode(struct docg3 *docg3, u8 mode)
266 {
267 	int i;
268 
269 	for (i = 0; i < 12; i++)
270 		doc_readb(docg3, DOC_IOSPACE_IPL);
271 
272 	mode |= DOC_ASICMODE_MDWREN;
273 	doc_dbg("doc_set_asic_mode(%02x)\n", mode);
274 	doc_writeb(docg3, mode, DOC_ASICMODE);
275 	doc_writeb(docg3, ~mode, DOC_ASICMODECONFIRM);
276 	doc_delay(docg3, 1);
277 }
278 
279 /**
280  * doc_set_device_id - Sets the devices id for cascaded G3 chips
281  * @docg3: the device
282  * @id: the chip to select (amongst 0, 1, 2, 3)
283  *
284  * There can be 4 cascaded G3 chips. This function selects the one which will
285  * should be the active one.
286  */
287 static void doc_set_device_id(struct docg3 *docg3, int id)
288 {
289 	u8 ctrl;
290 
291 	doc_dbg("doc_set_device_id(%d)\n", id);
292 	doc_writeb(docg3, id, DOC_DEVICESELECT);
293 	ctrl = doc_register_readb(docg3, DOC_FLASHCONTROL);
294 
295 	ctrl &= ~DOC_CTRL_VIOLATION;
296 	ctrl |= DOC_CTRL_CE;
297 	doc_writeb(docg3, ctrl, DOC_FLASHCONTROL);
298 }
299 
300 /**
301  * doc_set_extra_page_mode - Change flash page layout
302  * @docg3: the device
303  *
304  * Normally, the flash page is split into the data (512 bytes) and the out of
305  * band data (16 bytes). For each, 4 more bytes can be accessed, where the wear
306  * leveling counters are stored.  To access this last area of 4 bytes, a special
307  * mode must be input to the flash ASIC.
308  *
309  * Returns 0 if no error occured, -EIO else.
310  */
311 static int doc_set_extra_page_mode(struct docg3 *docg3)
312 {
313 	int fctrl;
314 
315 	doc_dbg("doc_set_extra_page_mode()\n");
316 	doc_flash_sequence(docg3, DOC_SEQ_PAGE_SIZE_532);
317 	doc_flash_command(docg3, DOC_CMD_PAGE_SIZE_532);
318 	doc_delay(docg3, 2);
319 
320 	fctrl = doc_register_readb(docg3, DOC_FLASHCONTROL);
321 	if (fctrl & (DOC_CTRL_PROTECTION_ERROR | DOC_CTRL_SEQUENCE_ERROR))
322 		return -EIO;
323 	else
324 		return 0;
325 }
326 
327 /**
328  * doc_seek - Set both flash planes to the specified block, page for reading
329  * @docg3: the device
330  * @block0: the first plane block index
331  * @block1: the second plane block index
332  * @page: the page index within the block
333  * @wear: if true, read will occur on the 4 extra bytes of the wear area
334  * @ofs: offset in page to read
335  *
336  * Programs the flash even and odd planes to the specific block and page.
337  * Alternatively, programs the flash to the wear area of the specified page.
338  */
339 static int doc_read_seek(struct docg3 *docg3, int block0, int block1, int page,
340 			 int wear, int ofs)
341 {
342 	int sector, ret = 0;
343 
344 	doc_dbg("doc_seek(blocks=(%d,%d), page=%d, ofs=%d, wear=%d)\n",
345 		block0, block1, page, ofs, wear);
346 
347 	if (!wear && (ofs < 2 * DOC_LAYOUT_PAGE_SIZE)) {
348 		doc_flash_sequence(docg3, DOC_SEQ_SET_PLANE1);
349 		doc_flash_command(docg3, DOC_CMD_READ_PLANE1);
350 		doc_delay(docg3, 2);
351 	} else {
352 		doc_flash_sequence(docg3, DOC_SEQ_SET_PLANE2);
353 		doc_flash_command(docg3, DOC_CMD_READ_PLANE2);
354 		doc_delay(docg3, 2);
355 	}
356 
357 	doc_set_reliable_mode(docg3);
358 	if (wear)
359 		ret = doc_set_extra_page_mode(docg3);
360 	if (ret)
361 		goto out;
362 
363 	sector = (block0 << DOC_ADDR_BLOCK_SHIFT) + (page & DOC_ADDR_PAGE_MASK);
364 	doc_flash_sequence(docg3, DOC_SEQ_READ);
365 	doc_flash_command(docg3, DOC_CMD_PROG_BLOCK_ADDR);
366 	doc_delay(docg3, 1);
367 	doc_flash_address(docg3, sector & 0xff);
368 	doc_flash_address(docg3, (sector >> 8) & 0xff);
369 	doc_flash_address(docg3, (sector >> 16) & 0xff);
370 	doc_delay(docg3, 1);
371 
372 	sector = (block1 << DOC_ADDR_BLOCK_SHIFT) + (page & DOC_ADDR_PAGE_MASK);
373 	doc_flash_command(docg3, DOC_CMD_PROG_BLOCK_ADDR);
374 	doc_delay(docg3, 1);
375 	doc_flash_address(docg3, sector & 0xff);
376 	doc_flash_address(docg3, (sector >> 8) & 0xff);
377 	doc_flash_address(docg3, (sector >> 16) & 0xff);
378 	doc_delay(docg3, 2);
379 
380 out:
381 	return ret;
382 }
383 
384 /**
385  * doc_read_page_ecc_init - Initialize hardware ECC engine
386  * @docg3: the device
387  * @len: the number of bytes covered by the ECC (BCH covered)
388  *
389  * The function does initialize the hardware ECC engine to compute the Hamming
390  * ECC (on 1 byte) and the BCH Syndroms (on 7 bytes).
391  *
392  * Return 0 if succeeded, -EIO on error
393  */
394 static int doc_read_page_ecc_init(struct docg3 *docg3, int len)
395 {
396 	doc_writew(docg3, DOC_ECCCONF0_READ_MODE
397 		   | DOC_ECCCONF0_BCH_ENABLE | DOC_ECCCONF0_HAMMING_ENABLE
398 		   | (len & DOC_ECCCONF0_DATA_BYTES_MASK),
399 		   DOC_ECCCONF0);
400 	doc_delay(docg3, 4);
401 	doc_register_readb(docg3, DOC_FLASHCONTROL);
402 	return doc_wait_ready(docg3);
403 }
404 
405 /**
406  * doc_read_page_prepare - Prepares reading data from a flash page
407  * @docg3: the device
408  * @block0: the first plane block index on flash memory
409  * @block1: the second plane block index on flash memory
410  * @page: the page index in the block
411  * @offset: the offset in the page (must be a multiple of 4)
412  *
413  * Prepares the page to be read in the flash memory :
414  *   - tell ASIC to map the flash pages
415  *   - tell ASIC to be in read mode
416  *
417  * After a call to this method, a call to doc_read_page_finish is mandatory,
418  * to end the read cycle of the flash.
419  *
420  * Read data from a flash page. The length to be read must be between 0 and
421  * (page_size + oob_size + wear_size), ie. 532, and a multiple of 4 (because
422  * the extra bytes reading is not implemented).
423  *
424  * As pages are grouped by 2 (in 2 planes), reading from a page must be done
425  * in two steps:
426  *  - one read of 512 bytes at offset 0
427  *  - one read of 512 bytes at offset 512 + 16
428  *
429  * Returns 0 if successful, -EIO if a read error occured.
430  */
431 static int doc_read_page_prepare(struct docg3 *docg3, int block0, int block1,
432 				 int page, int offset)
433 {
434 	int wear_area = 0, ret = 0;
435 
436 	doc_dbg("doc_read_page_prepare(blocks=(%d,%d), page=%d, ofsInPage=%d)\n",
437 		block0, block1, page, offset);
438 	if (offset >= DOC_LAYOUT_WEAR_OFFSET)
439 		wear_area = 1;
440 	if (!wear_area && offset > (DOC_LAYOUT_PAGE_OOB_SIZE * 2))
441 		return -EINVAL;
442 
443 	doc_set_device_id(docg3, docg3->device_id);
444 	ret = doc_reset_seq(docg3);
445 	if (ret)
446 		goto err;
447 
448 	/* Program the flash address block and page */
449 	ret = doc_read_seek(docg3, block0, block1, page, wear_area, offset);
450 	if (ret)
451 		goto err;
452 
453 	doc_flash_command(docg3, DOC_CMD_READ_ALL_PLANES);
454 	doc_delay(docg3, 2);
455 	doc_wait_ready(docg3);
456 
457 	doc_flash_command(docg3, DOC_CMD_SET_ADDR_READ);
458 	doc_delay(docg3, 1);
459 	if (offset >= DOC_LAYOUT_PAGE_SIZE * 2)
460 		offset -= 2 * DOC_LAYOUT_PAGE_SIZE;
461 	doc_flash_address(docg3, offset >> 2);
462 	doc_delay(docg3, 1);
463 	doc_wait_ready(docg3);
464 
465 	doc_flash_command(docg3, DOC_CMD_READ_FLASH);
466 
467 	return 0;
468 err:
469 	doc_writeb(docg3, 0, DOC_DATAEND);
470 	doc_delay(docg3, 2);
471 	return -EIO;
472 }
473 
474 /**
475  * doc_read_page_getbytes - Reads bytes from a prepared page
476  * @docg3: the device
477  * @len: the number of bytes to be read (must be a multiple of 4)
478  * @buf: the buffer to be filled in
479  * @first: 1 if first time read, DOC_READADDRESS should be set
480  *
481  */
482 static int doc_read_page_getbytes(struct docg3 *docg3, int len, u_char *buf,
483 				  int first)
484 {
485 	doc_read_data_area(docg3, buf, len, first);
486 	doc_delay(docg3, 2);
487 	return len;
488 }
489 
490 /**
491  * doc_get_hw_bch_syndroms - Get hardware calculated BCH syndroms
492  * @docg3: the device
493  * @syns:  the array of 7 integers where the syndroms will be stored
494  */
495 static void doc_get_hw_bch_syndroms(struct docg3 *docg3, int *syns)
496 {
497 	int i;
498 
499 	for (i = 0; i < DOC_ECC_BCH_SIZE; i++)
500 		syns[i] = doc_register_readb(docg3, DOC_BCH_SYNDROM(i));
501 }
502 
503 /**
504  * doc_read_page_finish - Ends reading of a flash page
505  * @docg3: the device
506  *
507  * As a side effect, resets the chip selector to 0. This ensures that after each
508  * read operation, the floor 0 is selected. Therefore, if the systems halts, the
509  * reboot will boot on floor 0, where the IPL is.
510  */
511 static void doc_read_page_finish(struct docg3 *docg3)
512 {
513 	doc_writeb(docg3, 0, DOC_DATAEND);
514 	doc_delay(docg3, 2);
515 	doc_set_device_id(docg3, 0);
516 }
517 
518 /**
519  * calc_block_sector - Calculate blocks, pages and ofs.
520 
521  * @from: offset in flash
522  * @block0: first plane block index calculated
523  * @block1: second plane block index calculated
524  * @page: page calculated
525  * @ofs: offset in page
526  */
527 static void calc_block_sector(loff_t from, int *block0, int *block1, int *page,
528 			      int *ofs)
529 {
530 	uint sector;
531 
532 	sector = from / DOC_LAYOUT_PAGE_SIZE;
533 	*block0 = sector / (DOC_LAYOUT_PAGES_PER_BLOCK * DOC_LAYOUT_NBPLANES)
534 		* DOC_LAYOUT_NBPLANES;
535 	*block1 = *block0 + 1;
536 	*page = sector % (DOC_LAYOUT_PAGES_PER_BLOCK * DOC_LAYOUT_NBPLANES);
537 	*page /= DOC_LAYOUT_NBPLANES;
538 	if (sector % 2)
539 		*ofs = DOC_LAYOUT_PAGE_OOB_SIZE;
540 	else
541 		*ofs = 0;
542 }
543 
544 /**
545  * doc_read - Read bytes from flash
546  * @mtd: the device
547  * @from: the offset from first block and first page, in bytes, aligned on page
548  *        size
549  * @len: the number of bytes to read (must be a multiple of 4)
550  * @retlen: the number of bytes actually read
551  * @buf: the filled in buffer
552  *
553  * Reads flash memory pages. This function does not read the OOB chunk, but only
554  * the page data.
555  *
556  * Returns 0 if read successfull, of -EIO, -EINVAL if an error occured
557  */
558 static int doc_read(struct mtd_info *mtd, loff_t from, size_t len,
559 	     size_t *retlen, u_char *buf)
560 {
561 	struct docg3 *docg3 = mtd->priv;
562 	int block0, block1, page, readlen, ret, ofs = 0;
563 	int syn[DOC_ECC_BCH_SIZE], eccconf1;
564 	u8 oob[DOC_LAYOUT_OOB_SIZE];
565 
566 	ret = -EINVAL;
567 	doc_dbg("doc_read(from=%lld, len=%zu, buf=%p)\n", from, len, buf);
568 	if (from % DOC_LAYOUT_PAGE_SIZE)
569 		goto err;
570 	if (len % 4)
571 		goto err;
572 	calc_block_sector(from, &block0, &block1, &page, &ofs);
573 	if (block1 > docg3->max_block)
574 		goto err;
575 
576 	*retlen = 0;
577 	ret = 0;
578 	readlen = min_t(size_t, len, (size_t)DOC_LAYOUT_PAGE_SIZE);
579 	while (!ret && len > 0) {
580 		readlen = min_t(size_t, len, (size_t)DOC_LAYOUT_PAGE_SIZE);
581 		ret = doc_read_page_prepare(docg3, block0, block1, page, ofs);
582 		if (ret < 0)
583 			goto err;
584 		ret = doc_read_page_ecc_init(docg3, DOC_ECC_BCH_COVERED_BYTES);
585 		if (ret < 0)
586 			goto err_in_read;
587 		ret = doc_read_page_getbytes(docg3, readlen, buf, 1);
588 		if (ret < readlen)
589 			goto err_in_read;
590 		ret = doc_read_page_getbytes(docg3, DOC_LAYOUT_OOB_SIZE,
591 					     oob, 0);
592 		if (ret < DOC_LAYOUT_OOB_SIZE)
593 			goto err_in_read;
594 
595 		*retlen += readlen;
596 		buf += readlen;
597 		len -= readlen;
598 
599 		ofs ^= DOC_LAYOUT_PAGE_OOB_SIZE;
600 		if (ofs == 0)
601 			page += 2;
602 		if (page > DOC_ADDR_PAGE_MASK) {
603 			page = 0;
604 			block0 += 2;
605 			block1 += 2;
606 		}
607 
608 		/*
609 		 * There should be a BCH bitstream fixing algorithm here ...
610 		 * By now, a page read failure is triggered by BCH error
611 		 */
612 		doc_get_hw_bch_syndroms(docg3, syn);
613 		eccconf1 = doc_register_readb(docg3, DOC_ECCCONF1);
614 
615 		doc_dbg("OOB - INFO: %02x:%02x:%02x:%02x:%02x:%02x:%02x\n",
616 			 oob[0], oob[1], oob[2], oob[3], oob[4],
617 			 oob[5], oob[6]);
618 		doc_dbg("OOB - HAMMING: %02x\n", oob[7]);
619 		doc_dbg("OOB - BCH_ECC: %02x:%02x:%02x:%02x:%02x:%02x:%02x\n",
620 			 oob[8], oob[9], oob[10], oob[11], oob[12],
621 			 oob[13], oob[14]);
622 		doc_dbg("OOB - UNUSED: %02x\n", oob[15]);
623 		doc_dbg("ECC checks: ECCConf1=%x\n", eccconf1);
624 		doc_dbg("ECC BCH syndrom: %02x:%02x:%02x:%02x:%02x:%02x:%02x\n",
625 			syn[0], syn[1], syn[2], syn[3], syn[4], syn[5], syn[6]);
626 
627 		ret = -EBADMSG;
628 		if (block0 >= DOC_LAYOUT_BLOCK_FIRST_DATA) {
629 			if (eccconf1 & DOC_ECCCONF1_BCH_SYNDROM_ERR)
630 				goto err_in_read;
631 			if (is_prot_seq_error(docg3))
632 				goto err_in_read;
633 		}
634 		doc_read_page_finish(docg3);
635 	}
636 
637 	return 0;
638 err_in_read:
639 	doc_read_page_finish(docg3);
640 err:
641 	return ret;
642 }
643 
644 /**
645  * doc_read_oob - Read out of band bytes from flash
646  * @mtd: the device
647  * @from: the offset from first block and first page, in bytes, aligned on page
648  *        size
649  * @ops: the mtd oob structure
650  *
651  * Reads flash memory OOB area of pages.
652  *
653  * Returns 0 if read successfull, of -EIO, -EINVAL if an error occured
654  */
655 static int doc_read_oob(struct mtd_info *mtd, loff_t from,
656 			struct mtd_oob_ops *ops)
657 {
658 	struct docg3 *docg3 = mtd->priv;
659 	int block0, block1, page, ofs, ret;
660 	u8 *buf = ops->oobbuf;
661 	size_t len = ops->ooblen;
662 
663 	doc_dbg("doc_read_oob(from=%lld, buf=%p, len=%zu)\n", from, buf, len);
664 	if (len != DOC_LAYOUT_OOB_SIZE)
665 		return -EINVAL;
666 
667 	switch (ops->mode) {
668 	case MTD_OPS_PLACE_OOB:
669 		buf += ops->ooboffs;
670 		break;
671 	default:
672 		break;
673 	}
674 
675 	calc_block_sector(from, &block0, &block1, &page, &ofs);
676 	if (block1 > docg3->max_block)
677 		return -EINVAL;
678 
679 	ret = doc_read_page_prepare(docg3, block0, block1, page,
680 				    ofs + DOC_LAYOUT_PAGE_SIZE);
681 	if (!ret)
682 		ret = doc_read_page_ecc_init(docg3, DOC_LAYOUT_OOB_SIZE);
683 	if (!ret)
684 		ret = doc_read_page_getbytes(docg3, DOC_LAYOUT_OOB_SIZE,
685 					     buf, 1);
686 	doc_read_page_finish(docg3);
687 
688 	if (ret > 0)
689 		ops->oobretlen = ret;
690 	else
691 		ops->oobretlen = 0;
692 	return (ret > 0) ? 0 : ret;
693 }
694 
695 static int doc_reload_bbt(struct docg3 *docg3)
696 {
697 	int block = DOC_LAYOUT_BLOCK_BBT;
698 	int ret = 0, nbpages, page;
699 	u_char *buf = docg3->bbt;
700 
701 	nbpages = DIV_ROUND_UP(docg3->max_block + 1, 8 * DOC_LAYOUT_PAGE_SIZE);
702 	for (page = 0; !ret && (page < nbpages); page++) {
703 		ret = doc_read_page_prepare(docg3, block, block + 1,
704 					    page + DOC_LAYOUT_PAGE_BBT, 0);
705 		if (!ret)
706 			ret = doc_read_page_ecc_init(docg3,
707 						     DOC_LAYOUT_PAGE_SIZE);
708 		if (!ret)
709 			doc_read_page_getbytes(docg3, DOC_LAYOUT_PAGE_SIZE,
710 					       buf, 1);
711 		buf += DOC_LAYOUT_PAGE_SIZE;
712 	}
713 	doc_read_page_finish(docg3);
714 	return ret;
715 }
716 
717 /**
718  * doc_block_isbad - Checks whether a block is good or not
719  * @mtd: the device
720  * @from: the offset to find the correct block
721  *
722  * Returns 1 if block is bad, 0 if block is good
723  */
724 static int doc_block_isbad(struct mtd_info *mtd, loff_t from)
725 {
726 	struct docg3 *docg3 = mtd->priv;
727 	int block0, block1, page, ofs, is_good;
728 
729 	calc_block_sector(from, &block0, &block1, &page, &ofs);
730 	doc_dbg("doc_block_isbad(from=%lld) => block=(%d,%d), page=%d, ofs=%d\n",
731 		from, block0, block1, page, ofs);
732 
733 	if (block0 < DOC_LAYOUT_BLOCK_FIRST_DATA)
734 		return 0;
735 	if (block1 > docg3->max_block)
736 		return -EINVAL;
737 
738 	is_good = docg3->bbt[block0 >> 3] & (1 << (block0 & 0x7));
739 	return !is_good;
740 }
741 
742 /**
743  * doc_get_erase_count - Get block erase count
744  * @docg3: the device
745  * @from: the offset in which the block is.
746  *
747  * Get the number of times a block was erased. The number is the maximum of
748  * erase times between first and second plane (which should be equal normally).
749  *
750  * Returns The number of erases, or -EINVAL or -EIO on error.
751  */
752 static int doc_get_erase_count(struct docg3 *docg3, loff_t from)
753 {
754 	u8 buf[DOC_LAYOUT_WEAR_SIZE];
755 	int ret, plane1_erase_count, plane2_erase_count;
756 	int block0, block1, page, ofs;
757 
758 	doc_dbg("doc_get_erase_count(from=%lld, buf=%p)\n", from, buf);
759 	if (from % DOC_LAYOUT_PAGE_SIZE)
760 		return -EINVAL;
761 	calc_block_sector(from, &block0, &block1, &page, &ofs);
762 	if (block1 > docg3->max_block)
763 		return -EINVAL;
764 
765 	ret = doc_reset_seq(docg3);
766 	if (!ret)
767 		ret = doc_read_page_prepare(docg3, block0, block1, page,
768 					    ofs + DOC_LAYOUT_WEAR_OFFSET);
769 	if (!ret)
770 		ret = doc_read_page_getbytes(docg3, DOC_LAYOUT_WEAR_SIZE,
771 					     buf, 1);
772 	doc_read_page_finish(docg3);
773 
774 	if (ret || (buf[0] != DOC_ERASE_MARK) || (buf[2] != DOC_ERASE_MARK))
775 		return -EIO;
776 	plane1_erase_count = (u8)(~buf[1]) | ((u8)(~buf[4]) << 8)
777 		| ((u8)(~buf[5]) << 16);
778 	plane2_erase_count = (u8)(~buf[3]) | ((u8)(~buf[6]) << 8)
779 		| ((u8)(~buf[7]) << 16);
780 
781 	return max(plane1_erase_count, plane2_erase_count);
782 }
783 
784 /*
785  * Debug sysfs entries
786  */
787 static int dbg_flashctrl_show(struct seq_file *s, void *p)
788 {
789 	struct docg3 *docg3 = (struct docg3 *)s->private;
790 
791 	int pos = 0;
792 	u8 fctrl = doc_register_readb(docg3, DOC_FLASHCONTROL);
793 
794 	pos += seq_printf(s,
795 		 "FlashControl : 0x%02x (%s,CE# %s,%s,%s,flash %s)\n",
796 		 fctrl,
797 		 fctrl & DOC_CTRL_VIOLATION ? "protocol violation" : "-",
798 		 fctrl & DOC_CTRL_CE ? "active" : "inactive",
799 		 fctrl & DOC_CTRL_PROTECTION_ERROR ? "protection error" : "-",
800 		 fctrl & DOC_CTRL_SEQUENCE_ERROR ? "sequence error" : "-",
801 		 fctrl & DOC_CTRL_FLASHREADY ? "ready" : "not ready");
802 	return pos;
803 }
804 DEBUGFS_RO_ATTR(flashcontrol, dbg_flashctrl_show);
805 
806 static int dbg_asicmode_show(struct seq_file *s, void *p)
807 {
808 	struct docg3 *docg3 = (struct docg3 *)s->private;
809 
810 	int pos = 0;
811 	int pctrl = doc_register_readb(docg3, DOC_ASICMODE);
812 	int mode = pctrl & 0x03;
813 
814 	pos += seq_printf(s,
815 			 "%04x : RAM_WE=%d,RSTIN_RESET=%d,BDETCT_RESET=%d,WRITE_ENABLE=%d,POWERDOWN=%d,MODE=%d%d (",
816 			 pctrl,
817 			 pctrl & DOC_ASICMODE_RAM_WE ? 1 : 0,
818 			 pctrl & DOC_ASICMODE_RSTIN_RESET ? 1 : 0,
819 			 pctrl & DOC_ASICMODE_BDETCT_RESET ? 1 : 0,
820 			 pctrl & DOC_ASICMODE_MDWREN ? 1 : 0,
821 			 pctrl & DOC_ASICMODE_POWERDOWN ? 1 : 0,
822 			 mode >> 1, mode & 0x1);
823 
824 	switch (mode) {
825 	case DOC_ASICMODE_RESET:
826 		pos += seq_printf(s, "reset");
827 		break;
828 	case DOC_ASICMODE_NORMAL:
829 		pos += seq_printf(s, "normal");
830 		break;
831 	case DOC_ASICMODE_POWERDOWN:
832 		pos += seq_printf(s, "powerdown");
833 		break;
834 	}
835 	pos += seq_printf(s, ")\n");
836 	return pos;
837 }
838 DEBUGFS_RO_ATTR(asic_mode, dbg_asicmode_show);
839 
840 static int dbg_device_id_show(struct seq_file *s, void *p)
841 {
842 	struct docg3 *docg3 = (struct docg3 *)s->private;
843 	int pos = 0;
844 	int id = doc_register_readb(docg3, DOC_DEVICESELECT);
845 
846 	pos += seq_printf(s, "DeviceId = %d\n", id);
847 	return pos;
848 }
849 DEBUGFS_RO_ATTR(device_id, dbg_device_id_show);
850 
851 static int dbg_protection_show(struct seq_file *s, void *p)
852 {
853 	struct docg3 *docg3 = (struct docg3 *)s->private;
854 	int pos = 0;
855 	int protect = doc_register_readb(docg3, DOC_PROTECTION);
856 	int dps0 = doc_register_readb(docg3, DOC_DPS0_STATUS);
857 	int dps0_low = doc_register_readb(docg3, DOC_DPS0_ADDRLOW);
858 	int dps0_high = doc_register_readb(docg3, DOC_DPS0_ADDRHIGH);
859 	int dps1 = doc_register_readb(docg3, DOC_DPS1_STATUS);
860 	int dps1_low = doc_register_readb(docg3, DOC_DPS1_ADDRLOW);
861 	int dps1_high = doc_register_readb(docg3, DOC_DPS1_ADDRHIGH);
862 
863 	pos += seq_printf(s, "Protection = 0x%02x (",
864 			 protect);
865 	if (protect & DOC_PROTECT_FOUNDRY_OTP_LOCK)
866 		pos += seq_printf(s, "FOUNDRY_OTP_LOCK,");
867 	if (protect & DOC_PROTECT_CUSTOMER_OTP_LOCK)
868 		pos += seq_printf(s, "CUSTOMER_OTP_LOCK,");
869 	if (protect & DOC_PROTECT_LOCK_INPUT)
870 		pos += seq_printf(s, "LOCK_INPUT,");
871 	if (protect & DOC_PROTECT_STICKY_LOCK)
872 		pos += seq_printf(s, "STICKY_LOCK,");
873 	if (protect & DOC_PROTECT_PROTECTION_ENABLED)
874 		pos += seq_printf(s, "PROTECTION ON,");
875 	if (protect & DOC_PROTECT_IPL_DOWNLOAD_LOCK)
876 		pos += seq_printf(s, "IPL_DOWNLOAD_LOCK,");
877 	if (protect & DOC_PROTECT_PROTECTION_ERROR)
878 		pos += seq_printf(s, "PROTECT_ERR,");
879 	else
880 		pos += seq_printf(s, "NO_PROTECT_ERR");
881 	pos += seq_printf(s, ")\n");
882 
883 	pos += seq_printf(s, "DPS0 = 0x%02x : "
884 			 "Protected area [0x%x - 0x%x] : OTP=%d, READ=%d, "
885 			 "WRITE=%d, HW_LOCK=%d, KEY_OK=%d\n",
886 			 dps0, dps0_low, dps0_high,
887 			 !!(dps0 & DOC_DPS_OTP_PROTECTED),
888 			 !!(dps0 & DOC_DPS_READ_PROTECTED),
889 			 !!(dps0 & DOC_DPS_WRITE_PROTECTED),
890 			 !!(dps0 & DOC_DPS_HW_LOCK_ENABLED),
891 			 !!(dps0 & DOC_DPS_KEY_OK));
892 	pos += seq_printf(s, "DPS1 = 0x%02x : "
893 			 "Protected area [0x%x - 0x%x] : OTP=%d, READ=%d, "
894 			 "WRITE=%d, HW_LOCK=%d, KEY_OK=%d\n",
895 			 dps1, dps1_low, dps1_high,
896 			 !!(dps1 & DOC_DPS_OTP_PROTECTED),
897 			 !!(dps1 & DOC_DPS_READ_PROTECTED),
898 			 !!(dps1 & DOC_DPS_WRITE_PROTECTED),
899 			 !!(dps1 & DOC_DPS_HW_LOCK_ENABLED),
900 			 !!(dps1 & DOC_DPS_KEY_OK));
901 	return pos;
902 }
903 DEBUGFS_RO_ATTR(protection, dbg_protection_show);
904 
905 static int __init doc_dbg_register(struct docg3 *docg3)
906 {
907 	struct dentry *root, *entry;
908 
909 	root = debugfs_create_dir("docg3", NULL);
910 	if (!root)
911 		return -ENOMEM;
912 
913 	entry = debugfs_create_file("flashcontrol", S_IRUSR, root, docg3,
914 				  &flashcontrol_fops);
915 	if (entry)
916 		entry = debugfs_create_file("asic_mode", S_IRUSR, root,
917 					    docg3, &asic_mode_fops);
918 	if (entry)
919 		entry = debugfs_create_file("device_id", S_IRUSR, root,
920 					    docg3, &device_id_fops);
921 	if (entry)
922 		entry = debugfs_create_file("protection", S_IRUSR, root,
923 					    docg3, &protection_fops);
924 	if (entry) {
925 		docg3->debugfs_root = root;
926 		return 0;
927 	} else {
928 		debugfs_remove_recursive(root);
929 		return -ENOMEM;
930 	}
931 }
932 
933 static void __exit doc_dbg_unregister(struct docg3 *docg3)
934 {
935 	debugfs_remove_recursive(docg3->debugfs_root);
936 }
937 
938 /**
939  * doc_set_driver_info - Fill the mtd_info structure and docg3 structure
940  * @chip_id: The chip ID of the supported chip
941  * @mtd: The structure to fill
942  */
943 static void __init doc_set_driver_info(int chip_id, struct mtd_info *mtd)
944 {
945 	struct docg3 *docg3 = mtd->priv;
946 	int cfg;
947 
948 	cfg = doc_register_readb(docg3, DOC_CONFIGURATION);
949 	docg3->if_cfg = (cfg & DOC_CONF_IF_CFG ? 1 : 0);
950 
951 	switch (chip_id) {
952 	case DOC_CHIPID_G3:
953 		mtd->name = "DiskOnChip G3";
954 		docg3->max_block = 2047;
955 		break;
956 	}
957 	mtd->type = MTD_NANDFLASH;
958 	/*
959 	 * Once write methods are added, the correct flags will be set.
960 	 * mtd->flags = MTD_CAP_NANDFLASH;
961 	 */
962 	mtd->flags = MTD_CAP_ROM;
963 	mtd->size = (docg3->max_block + 1) * DOC_LAYOUT_BLOCK_SIZE;
964 	mtd->erasesize = DOC_LAYOUT_BLOCK_SIZE * DOC_LAYOUT_NBPLANES;
965 	mtd->writesize = DOC_LAYOUT_PAGE_SIZE;
966 	mtd->oobsize = DOC_LAYOUT_OOB_SIZE;
967 	mtd->owner = THIS_MODULE;
968 	mtd->erase = NULL;
969 	mtd->point = NULL;
970 	mtd->unpoint = NULL;
971 	mtd->read = doc_read;
972 	mtd->write = NULL;
973 	mtd->read_oob = doc_read_oob;
974 	mtd->write_oob = NULL;
975 	mtd->sync = NULL;
976 	mtd->block_isbad = doc_block_isbad;
977 }
978 
979 /**
980  * doc_probe - Probe the IO space for a DiskOnChip G3 chip
981  * @pdev: platform device
982  *
983  * Probes for a G3 chip at the specified IO space in the platform data
984  * ressources.
985  *
986  * Returns 0 on success, -ENOMEM, -ENXIO on error
987  */
988 static int __init docg3_probe(struct platform_device *pdev)
989 {
990 	struct device *dev = &pdev->dev;
991 	struct docg3 *docg3;
992 	struct mtd_info *mtd;
993 	struct resource *ress;
994 	int ret, bbt_nbpages;
995 	u16 chip_id, chip_id_inv;
996 
997 	ret = -ENOMEM;
998 	docg3 = kzalloc(sizeof(struct docg3), GFP_KERNEL);
999 	if (!docg3)
1000 		goto nomem1;
1001 	mtd = kzalloc(sizeof(struct mtd_info), GFP_KERNEL);
1002 	if (!mtd)
1003 		goto nomem2;
1004 	mtd->priv = docg3;
1005 
1006 	ret = -ENXIO;
1007 	ress = platform_get_resource(pdev, IORESOURCE_MEM, 0);
1008 	if (!ress) {
1009 		dev_err(dev, "No I/O memory resource defined\n");
1010 		goto noress;
1011 	}
1012 	docg3->base = ioremap(ress->start, DOC_IOSPACE_SIZE);
1013 
1014 	docg3->dev = &pdev->dev;
1015 	docg3->device_id = 0;
1016 	doc_set_device_id(docg3, docg3->device_id);
1017 	doc_set_asic_mode(docg3, DOC_ASICMODE_RESET);
1018 	doc_set_asic_mode(docg3, DOC_ASICMODE_NORMAL);
1019 
1020 	chip_id = doc_register_readw(docg3, DOC_CHIPID);
1021 	chip_id_inv = doc_register_readw(docg3, DOC_CHIPID_INV);
1022 
1023 	ret = -ENODEV;
1024 	if (chip_id != (u16)(~chip_id_inv)) {
1025 		doc_info("No device found at IO addr %p\n",
1026 			 (void *)ress->start);
1027 		goto nochipfound;
1028 	}
1029 
1030 	switch (chip_id) {
1031 	case DOC_CHIPID_G3:
1032 		doc_info("Found a G3 DiskOnChip at addr %p\n",
1033 			 (void *)ress->start);
1034 		break;
1035 	default:
1036 		doc_err("Chip id %04x is not a DiskOnChip G3 chip\n", chip_id);
1037 		goto nochipfound;
1038 	}
1039 
1040 	doc_set_driver_info(chip_id, mtd);
1041 	platform_set_drvdata(pdev, mtd);
1042 
1043 	ret = -ENOMEM;
1044 	bbt_nbpages = DIV_ROUND_UP(docg3->max_block + 1,
1045 				   8 * DOC_LAYOUT_PAGE_SIZE);
1046 	docg3->bbt = kzalloc(bbt_nbpages * DOC_LAYOUT_PAGE_SIZE, GFP_KERNEL);
1047 	if (!docg3->bbt)
1048 		goto nochipfound;
1049 	doc_reload_bbt(docg3);
1050 
1051 	ret = mtd_device_parse_register(mtd, part_probes,
1052 					NULL, NULL, 0);
1053 	if (ret)
1054 		goto register_error;
1055 
1056 	doc_dbg_register(docg3);
1057 	return 0;
1058 
1059 register_error:
1060 	kfree(docg3->bbt);
1061 nochipfound:
1062 	iounmap(docg3->base);
1063 noress:
1064 	kfree(mtd);
1065 nomem2:
1066 	kfree(docg3);
1067 nomem1:
1068 	return ret;
1069 }
1070 
1071 /**
1072  * docg3_release - Release the driver
1073  * @pdev: the platform device
1074  *
1075  * Returns 0
1076  */
1077 static int __exit docg3_release(struct platform_device *pdev)
1078 {
1079 	struct mtd_info *mtd = platform_get_drvdata(pdev);
1080 	struct docg3 *docg3 = mtd->priv;
1081 
1082 	doc_dbg_unregister(docg3);
1083 	mtd_device_unregister(mtd);
1084 	iounmap(docg3->base);
1085 	kfree(docg3->bbt);
1086 	kfree(docg3);
1087 	kfree(mtd);
1088 	return 0;
1089 }
1090 
1091 static struct platform_driver g3_driver = {
1092 	.driver		= {
1093 		.name	= "docg3",
1094 		.owner	= THIS_MODULE,
1095 	},
1096 	.remove		= __exit_p(docg3_release),
1097 };
1098 
1099 static int __init docg3_init(void)
1100 {
1101 	return platform_driver_probe(&g3_driver, docg3_probe);
1102 }
1103 module_init(docg3_init);
1104 
1105 
1106 static void __exit docg3_exit(void)
1107 {
1108 	platform_driver_unregister(&g3_driver);
1109 }
1110 module_exit(docg3_exit);
1111 
1112 MODULE_LICENSE("GPL");
1113 MODULE_AUTHOR("Robert Jarzmik <robert.jarzmik@free.fr>");
1114 MODULE_DESCRIPTION("MTD driver for DiskOnChip G3");
1115