1/*
2 *  Copyright © 2012 Mike Dunn <mikedunn@newsguy.com>
3 *
4 * mtd nand driver for M-Systems DiskOnChip G4
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 * Tested on the Palm Treo 680.  The G4 is also present on Toshiba Portege, Asus
12 * P526, some HTC smartphones (Wizard, Prophet, ...), O2 XDA Zinc, maybe others.
13 * Should work on these as well.  Let me know!
14 *
15 * TODO:
16 *
17 *  Mechanism for management of password-protected areas
18 *
19 *  Hamming ecc when reading oob only
20 *
21 *  According to the M-Sys documentation, this device is also available in a
22 *  "dual-die" configuration having a 256MB capacity, but no mechanism for
23 *  detecting this variant is documented.  Currently this driver assumes 128MB
24 *  capacity.
25 *
26 *  Support for multiple cascaded devices ("floors").  Not sure which gadgets
27 *  contain multiple G4s in a cascaded configuration, if any.
28 *
29 */
30
31#include <linux/kernel.h>
32#include <linux/slab.h>
33#include <linux/init.h>
34#include <linux/string.h>
35#include <linux/sched.h>
36#include <linux/delay.h>
37#include <linux/module.h>
38#include <linux/export.h>
39#include <linux/platform_device.h>
40#include <linux/io.h>
41#include <linux/bitops.h>
42#include <linux/mtd/partitions.h>
43#include <linux/mtd/mtd.h>
44#include <linux/mtd/nand.h>
45#include <linux/bch.h>
46#include <linux/bitrev.h>
47#include <linux/jiffies.h>
48
49/*
50 * In "reliable mode" consecutive 2k pages are used in parallel (in some
51 * fashion) to store the same data.  The data can be read back from the
52 * even-numbered pages in the normal manner; odd-numbered pages will appear to
53 * contain junk.  Systems that boot from the docg4 typically write the secondary
54 * program loader (SPL) code in this mode.  The SPL is loaded by the initial
55 * program loader (IPL, stored in the docg4's 2k NOR-like region that is mapped
56 * to the reset vector address).  This module parameter enables you to use this
57 * driver to write the SPL.  When in this mode, no more than 2k of data can be
58 * written at a time, because the addresses do not increment in the normal
59 * manner, and the starting offset must be within an even-numbered 2k region;
60 * i.e., invalid starting offsets are 0x800, 0xa00, 0xc00, 0xe00, 0x1800,
61 * 0x1a00, ...  Reliable mode is a special case and should not be used unless
62 * you know what you're doing.
63 */
64static bool reliable_mode;
65module_param(reliable_mode, bool, 0);
66MODULE_PARM_DESC(reliable_mode, "pages are programmed in reliable mode");
67
68/*
69 * You'll want to ignore badblocks if you're reading a partition that contains
70 * data written by the TrueFFS library (i.e., by PalmOS, Windows, etc), since
71 * it does not use mtd nand's method for marking bad blocks (using oob area).
72 * This will also skip the check of the "page written" flag.
73 */
74static bool ignore_badblocks;
75module_param(ignore_badblocks, bool, 0);
76MODULE_PARM_DESC(ignore_badblocks, "no badblock checking performed");
77
78struct docg4_priv {
79	struct mtd_info	*mtd;
80	struct device *dev;
81	void __iomem *virtadr;
82	int status;
83	struct {
84		unsigned int command;
85		int column;
86		int page;
87	} last_command;
88	uint8_t oob_buf[16];
89	uint8_t ecc_buf[7];
90	int oob_page;
91	struct bch_control *bch;
92};
93
94/*
95 * Defines prefixed with DOCG4 are unique to the diskonchip G4.  All others are
96 * shared with other diskonchip devices (P3, G3 at least).
97 *
98 * Functions with names prefixed with docg4_ are mtd / nand interface functions
99 * (though they may also be called internally).  All others are internal.
100 */
101
102#define DOC_IOSPACE_DATA		0x0800
103
104/* register offsets */
105#define DOC_CHIPID			0x1000
106#define DOC_DEVICESELECT		0x100a
107#define DOC_ASICMODE			0x100c
108#define DOC_DATAEND			0x101e
109#define DOC_NOP				0x103e
110
111#define DOC_FLASHSEQUENCE		0x1032
112#define DOC_FLASHCOMMAND		0x1034
113#define DOC_FLASHADDRESS		0x1036
114#define DOC_FLASHCONTROL		0x1038
115#define DOC_ECCCONF0			0x1040
116#define DOC_ECCCONF1			0x1042
117#define DOC_HAMMINGPARITY		0x1046
118#define DOC_BCH_SYNDROM(idx)		(0x1048 + idx)
119
120#define DOC_ASICMODECONFIRM		0x1072
121#define DOC_CHIPID_INV			0x1074
122#define DOC_POWERMODE			0x107c
123
124#define DOCG4_MYSTERY_REG		0x1050
125
126/* apparently used only to write oob bytes 6 and 7 */
127#define DOCG4_OOB_6_7			0x1052
128
129/* DOC_FLASHSEQUENCE register commands */
130#define DOC_SEQ_RESET			0x00
131#define DOCG4_SEQ_PAGE_READ		0x03
132#define DOCG4_SEQ_FLUSH			0x29
133#define DOCG4_SEQ_PAGEWRITE		0x16
134#define DOCG4_SEQ_PAGEPROG		0x1e
135#define DOCG4_SEQ_BLOCKERASE		0x24
136#define DOCG4_SEQ_SETMODE		0x45
137
138/* DOC_FLASHCOMMAND register commands */
139#define DOCG4_CMD_PAGE_READ             0x00
140#define DOC_CMD_ERASECYCLE2		0xd0
141#define DOCG4_CMD_FLUSH                 0x70
142#define DOCG4_CMD_READ2                 0x30
143#define DOC_CMD_PROG_BLOCK_ADDR		0x60
144#define DOCG4_CMD_PAGEWRITE		0x80
145#define DOC_CMD_PROG_CYCLE2		0x10
146#define DOCG4_CMD_FAST_MODE		0xa3 /* functionality guessed */
147#define DOC_CMD_RELIABLE_MODE		0x22
148#define DOC_CMD_RESET			0xff
149
150/* DOC_POWERMODE register bits */
151#define DOC_POWERDOWN_READY		0x80
152
153/* DOC_FLASHCONTROL register bits */
154#define DOC_CTRL_CE			0x10
155#define DOC_CTRL_UNKNOWN		0x40
156#define DOC_CTRL_FLASHREADY		0x01
157
158/* DOC_ECCCONF0 register bits */
159#define DOC_ECCCONF0_READ_MODE		0x8000
160#define DOC_ECCCONF0_UNKNOWN		0x2000
161#define DOC_ECCCONF0_ECC_ENABLE	        0x1000
162#define DOC_ECCCONF0_DATA_BYTES_MASK	0x07ff
163
164/* DOC_ECCCONF1 register bits */
165#define DOC_ECCCONF1_BCH_SYNDROM_ERR	0x80
166#define DOC_ECCCONF1_ECC_ENABLE         0x07
167#define DOC_ECCCONF1_PAGE_IS_WRITTEN	0x20
168
169/* DOC_ASICMODE register bits */
170#define DOC_ASICMODE_RESET		0x00
171#define DOC_ASICMODE_NORMAL		0x01
172#define DOC_ASICMODE_POWERDOWN		0x02
173#define DOC_ASICMODE_MDWREN		0x04
174#define DOC_ASICMODE_BDETCT_RESET	0x08
175#define DOC_ASICMODE_RSTIN_RESET	0x10
176#define DOC_ASICMODE_RAM_WE		0x20
177
178/* good status values read after read/write/erase operations */
179#define DOCG4_PROGSTATUS_GOOD          0x51
180#define DOCG4_PROGSTATUS_GOOD_2        0xe0
181
182/*
183 * On read operations (page and oob-only), the first byte read from I/O reg is a
184 * status.  On error, it reads 0x73; otherwise, it reads either 0x71 (first read
185 * after reset only) or 0x51, so bit 1 is presumed to be an error indicator.
186 */
187#define DOCG4_READ_ERROR           0x02 /* bit 1 indicates read error */
188
189/* anatomy of the device */
190#define DOCG4_CHIP_SIZE        0x8000000
191#define DOCG4_PAGE_SIZE        0x200
192#define DOCG4_PAGES_PER_BLOCK  0x200
193#define DOCG4_BLOCK_SIZE       (DOCG4_PAGES_PER_BLOCK * DOCG4_PAGE_SIZE)
194#define DOCG4_NUMBLOCKS        (DOCG4_CHIP_SIZE / DOCG4_BLOCK_SIZE)
195#define DOCG4_OOB_SIZE         0x10
196#define DOCG4_CHIP_SHIFT       27    /* log_2(DOCG4_CHIP_SIZE) */
197#define DOCG4_PAGE_SHIFT       9     /* log_2(DOCG4_PAGE_SIZE) */
198#define DOCG4_ERASE_SHIFT      18    /* log_2(DOCG4_BLOCK_SIZE) */
199
200/* all but the last byte is included in ecc calculation */
201#define DOCG4_BCH_SIZE         (DOCG4_PAGE_SIZE + DOCG4_OOB_SIZE - 1)
202
203#define DOCG4_USERDATA_LEN     520 /* 512 byte page plus 8 oob avail to user */
204
205/* expected values from the ID registers */
206#define DOCG4_IDREG1_VALUE     0x0400
207#define DOCG4_IDREG2_VALUE     0xfbff
208
209/* primitive polynomial used to build the Galois field used by hw ecc gen */
210#define DOCG4_PRIMITIVE_POLY   0x4443
211
212#define DOCG4_M                14  /* Galois field is of order 2^14 */
213#define DOCG4_T                4   /* BCH alg corrects up to 4 bit errors */
214
215#define DOCG4_FACTORY_BBT_PAGE 16 /* page where read-only factory bbt lives */
216#define DOCG4_REDUNDANT_BBT_PAGE 24 /* page where redundant factory bbt lives */
217
218/*
219 * Bytes 0, 1 are used as badblock marker.
220 * Bytes 2 - 6 are available to the user.
221 * Byte 7 is hamming ecc for first 7 oob bytes only.
222 * Bytes 8 - 14 are hw-generated ecc covering entire page + oob bytes 0 - 14.
223 * Byte 15 (the last) is used by the driver as a "page written" flag.
224 */
225static struct nand_ecclayout docg4_oobinfo = {
226	.eccbytes = 9,
227	.eccpos = {7, 8, 9, 10, 11, 12, 13, 14, 15},
228	.oobavail = 5,
229	.oobfree = { {.offset = 2, .length = 5} }
230};
231
232/*
233 * The device has a nop register which M-Sys claims is for the purpose of
234 * inserting precise delays.  But beware; at least some operations fail if the
235 * nop writes are replaced with a generic delay!
236 */
237static inline void write_nop(void __iomem *docptr)
238{
239	writew(0, docptr + DOC_NOP);
240}
241
242static void docg4_read_buf(struct mtd_info *mtd, uint8_t *buf, int len)
243{
244	int i;
245	struct nand_chip *nand = mtd->priv;
246	uint16_t *p = (uint16_t *) buf;
247	len >>= 1;
248
249	for (i = 0; i < len; i++)
250		p[i] = readw(nand->IO_ADDR_R);
251}
252
253static void docg4_write_buf16(struct mtd_info *mtd, const uint8_t *buf, int len)
254{
255	int i;
256	struct nand_chip *nand = mtd->priv;
257	uint16_t *p = (uint16_t *) buf;
258	len >>= 1;
259
260	for (i = 0; i < len; i++)
261		writew(p[i], nand->IO_ADDR_W);
262}
263
264static int poll_status(struct docg4_priv *doc)
265{
266	/*
267	 * Busy-wait for the FLASHREADY bit to be set in the FLASHCONTROL
268	 * register.  Operations known to take a long time (e.g., block erase)
269	 * should sleep for a while before calling this.
270	 */
271
272	uint16_t flash_status;
273	unsigned long timeo;
274	void __iomem *docptr = doc->virtadr;
275
276	dev_dbg(doc->dev, "%s...\n", __func__);
277
278	/* hardware quirk requires reading twice initially */
279	flash_status = readw(docptr + DOC_FLASHCONTROL);
280
281	timeo = jiffies + msecs_to_jiffies(200); /* generous timeout */
282	do {
283		cpu_relax();
284		flash_status = readb(docptr + DOC_FLASHCONTROL);
285	} while (!(flash_status & DOC_CTRL_FLASHREADY) &&
286		 time_before(jiffies, timeo));
287
288	if (unlikely(!(flash_status & DOC_CTRL_FLASHREADY))) {
289		dev_err(doc->dev, "%s: timed out!\n", __func__);
290		return NAND_STATUS_FAIL;
291	}
292
293	return 0;
294}
295
296
297static int docg4_wait(struct mtd_info *mtd, struct nand_chip *nand)
298{
299
300	struct docg4_priv *doc = nand->priv;
301	int status = NAND_STATUS_WP;       /* inverse logic?? */
302	dev_dbg(doc->dev, "%s...\n", __func__);
303
304	/* report any previously unreported error */
305	if (doc->status) {
306		status |= doc->status;
307		doc->status = 0;
308		return status;
309	}
310
311	status |= poll_status(doc);
312	return status;
313}
314
315static void docg4_select_chip(struct mtd_info *mtd, int chip)
316{
317	/*
318	 * Select among multiple cascaded chips ("floors").  Multiple floors are
319	 * not yet supported, so the only valid non-negative value is 0.
320	 */
321	struct nand_chip *nand = mtd->priv;
322	struct docg4_priv *doc = nand->priv;
323	void __iomem *docptr = doc->virtadr;
324
325	dev_dbg(doc->dev, "%s: chip %d\n", __func__, chip);
326
327	if (chip < 0)
328		return;		/* deselected */
329
330	if (chip > 0)
331		dev_warn(doc->dev, "multiple floors currently unsupported\n");
332
333	writew(0, docptr + DOC_DEVICESELECT);
334}
335
336static void reset(struct mtd_info *mtd)
337{
338	/* full device reset */
339
340	struct nand_chip *nand = mtd->priv;
341	struct docg4_priv *doc = nand->priv;
342	void __iomem *docptr = doc->virtadr;
343
344	writew(DOC_ASICMODE_RESET | DOC_ASICMODE_MDWREN,
345	       docptr + DOC_ASICMODE);
346	writew(~(DOC_ASICMODE_RESET | DOC_ASICMODE_MDWREN),
347	       docptr + DOC_ASICMODECONFIRM);
348	write_nop(docptr);
349
350	writew(DOC_ASICMODE_NORMAL | DOC_ASICMODE_MDWREN,
351	       docptr + DOC_ASICMODE);
352	writew(~(DOC_ASICMODE_NORMAL | DOC_ASICMODE_MDWREN),
353	       docptr + DOC_ASICMODECONFIRM);
354
355	writew(DOC_ECCCONF1_ECC_ENABLE, docptr + DOC_ECCCONF1);
356
357	poll_status(doc);
358}
359
360static void read_hw_ecc(void __iomem *docptr, uint8_t *ecc_buf)
361{
362	/* read the 7 hw-generated ecc bytes */
363
364	int i;
365	for (i = 0; i < 7; i++) { /* hw quirk; read twice */
366		ecc_buf[i] = readb(docptr + DOC_BCH_SYNDROM(i));
367		ecc_buf[i] = readb(docptr + DOC_BCH_SYNDROM(i));
368	}
369}
370
371static int correct_data(struct mtd_info *mtd, uint8_t *buf, int page)
372{
373	/*
374	 * Called after a page read when hardware reports bitflips.
375	 * Up to four bitflips can be corrected.
376	 */
377
378	struct nand_chip *nand = mtd->priv;
379	struct docg4_priv *doc = nand->priv;
380	void __iomem *docptr = doc->virtadr;
381	int i, numerrs, errpos[4];
382	const uint8_t blank_read_hwecc[8] = {
383		0xcf, 0x72, 0xfc, 0x1b, 0xa9, 0xc7, 0xb9, 0 };
384
385	read_hw_ecc(docptr, doc->ecc_buf); /* read 7 hw-generated ecc bytes */
386
387	/* check if read error is due to a blank page */
388	if (!memcmp(doc->ecc_buf, blank_read_hwecc, 7))
389		return 0;	/* yes */
390
391	/* skip additional check of "written flag" if ignore_badblocks */
392	if (ignore_badblocks == false) {
393
394		/*
395		 * If the hw ecc bytes are not those of a blank page, there's
396		 * still a chance that the page is blank, but was read with
397		 * errors.  Check the "written flag" in last oob byte, which
398		 * is set to zero when a page is written.  If more than half
399		 * the bits are set, assume a blank page.  Unfortunately, the
400		 * bit flips(s) are not reported in stats.
401		 */
402
403		if (nand->oob_poi[15]) {
404			int bit, numsetbits = 0;
405			unsigned long written_flag = nand->oob_poi[15];
406			for_each_set_bit(bit, &written_flag, 8)
407				numsetbits++;
408			if (numsetbits > 4) { /* assume blank */
409				dev_warn(doc->dev,
410					 "error(s) in blank page "
411					 "at offset %08x\n",
412					 page * DOCG4_PAGE_SIZE);
413				return 0;
414			}
415		}
416	}
417
418	/*
419	 * The hardware ecc unit produces oob_ecc ^ calc_ecc.  The kernel's bch
420	 * algorithm is used to decode this.  However the hw operates on page
421	 * data in a bit order that is the reverse of that of the bch alg,
422	 * requiring that the bits be reversed on the result.  Thanks to Ivan
423	 * Djelic for his analysis!
424	 */
425	for (i = 0; i < 7; i++)
426		doc->ecc_buf[i] = bitrev8(doc->ecc_buf[i]);
427
428	numerrs = decode_bch(doc->bch, NULL, DOCG4_USERDATA_LEN, NULL,
429			     doc->ecc_buf, NULL, errpos);
430
431	if (numerrs == -EBADMSG) {
432		dev_warn(doc->dev, "uncorrectable errors at offset %08x\n",
433			 page * DOCG4_PAGE_SIZE);
434		return -EBADMSG;
435	}
436
437	BUG_ON(numerrs < 0);	/* -EINVAL, or anything other than -EBADMSG */
438
439	/* undo last step in BCH alg (modulo mirroring not needed) */
440	for (i = 0; i < numerrs; i++)
441		errpos[i] = (errpos[i] & ~7)|(7-(errpos[i] & 7));
442
443	/* fix the errors */
444	for (i = 0; i < numerrs; i++) {
445
446		/* ignore if error within oob ecc bytes */
447		if (errpos[i] > DOCG4_USERDATA_LEN * 8)
448			continue;
449
450		/* if error within oob area preceeding ecc bytes... */
451		if (errpos[i] > DOCG4_PAGE_SIZE * 8)
452			change_bit(errpos[i] - DOCG4_PAGE_SIZE * 8,
453				   (unsigned long *)nand->oob_poi);
454
455		else    /* error in page data */
456			change_bit(errpos[i], (unsigned long *)buf);
457	}
458
459	dev_notice(doc->dev, "%d error(s) corrected at offset %08x\n",
460		   numerrs, page * DOCG4_PAGE_SIZE);
461
462	return numerrs;
463}
464
465static uint8_t docg4_read_byte(struct mtd_info *mtd)
466{
467	struct nand_chip *nand = mtd->priv;
468	struct docg4_priv *doc = nand->priv;
469
470	dev_dbg(doc->dev, "%s\n", __func__);
471
472	if (doc->last_command.command == NAND_CMD_STATUS) {
473		int status;
474
475		/*
476		 * Previous nand command was status request, so nand
477		 * infrastructure code expects to read the status here.  If an
478		 * error occurred in a previous operation, report it.
479		 */
480		doc->last_command.command = 0;
481
482		if (doc->status) {
483			status = doc->status;
484			doc->status = 0;
485		}
486
487		/* why is NAND_STATUS_WP inverse logic?? */
488		else
489			status = NAND_STATUS_WP | NAND_STATUS_READY;
490
491		return status;
492	}
493
494	dev_warn(doc->dev, "unexpected call to read_byte()\n");
495
496	return 0;
497}
498
499static void write_addr(struct docg4_priv *doc, uint32_t docg4_addr)
500{
501	/* write the four address bytes packed in docg4_addr to the device */
502
503	void __iomem *docptr = doc->virtadr;
504	writeb(docg4_addr & 0xff, docptr + DOC_FLASHADDRESS);
505	docg4_addr >>= 8;
506	writeb(docg4_addr & 0xff, docptr + DOC_FLASHADDRESS);
507	docg4_addr >>= 8;
508	writeb(docg4_addr & 0xff, docptr + DOC_FLASHADDRESS);
509	docg4_addr >>= 8;
510	writeb(docg4_addr & 0xff, docptr + DOC_FLASHADDRESS);
511}
512
513static int read_progstatus(struct docg4_priv *doc)
514{
515	/*
516	 * This apparently checks the status of programming.  Done after an
517	 * erasure, and after page data is written.  On error, the status is
518	 * saved, to be later retrieved by the nand infrastructure code.
519	 */
520	void __iomem *docptr = doc->virtadr;
521
522	/* status is read from the I/O reg */
523	uint16_t status1 = readw(docptr + DOC_IOSPACE_DATA);
524	uint16_t status2 = readw(docptr + DOC_IOSPACE_DATA);
525	uint16_t status3 = readw(docptr + DOCG4_MYSTERY_REG);
526
527	dev_dbg(doc->dev, "docg4: %s: %02x %02x %02x\n",
528	      __func__, status1, status2, status3);
529
530	if (status1 != DOCG4_PROGSTATUS_GOOD
531	    || status2 != DOCG4_PROGSTATUS_GOOD_2
532	    || status3 != DOCG4_PROGSTATUS_GOOD_2) {
533		doc->status = NAND_STATUS_FAIL;
534		dev_warn(doc->dev, "read_progstatus failed: "
535			 "%02x, %02x, %02x\n", status1, status2, status3);
536		return -EIO;
537	}
538	return 0;
539}
540
541static int pageprog(struct mtd_info *mtd)
542{
543	/*
544	 * Final step in writing a page.  Writes the contents of its
545	 * internal buffer out to the flash array, or some such.
546	 */
547
548	struct nand_chip *nand = mtd->priv;
549	struct docg4_priv *doc = nand->priv;
550	void __iomem *docptr = doc->virtadr;
551	int retval = 0;
552
553	dev_dbg(doc->dev, "docg4: %s\n", __func__);
554
555	writew(DOCG4_SEQ_PAGEPROG, docptr + DOC_FLASHSEQUENCE);
556	writew(DOC_CMD_PROG_CYCLE2, docptr + DOC_FLASHCOMMAND);
557	write_nop(docptr);
558	write_nop(docptr);
559
560	/* Just busy-wait; usleep_range() slows things down noticeably. */
561	poll_status(doc);
562
563	writew(DOCG4_SEQ_FLUSH, docptr + DOC_FLASHSEQUENCE);
564	writew(DOCG4_CMD_FLUSH, docptr + DOC_FLASHCOMMAND);
565	writew(DOC_ECCCONF0_READ_MODE | 4, docptr + DOC_ECCCONF0);
566	write_nop(docptr);
567	write_nop(docptr);
568	write_nop(docptr);
569	write_nop(docptr);
570	write_nop(docptr);
571
572	retval = read_progstatus(doc);
573	writew(0, docptr + DOC_DATAEND);
574	write_nop(docptr);
575	poll_status(doc);
576	write_nop(docptr);
577
578	return retval;
579}
580
581static void sequence_reset(struct mtd_info *mtd)
582{
583	/* common starting sequence for all operations */
584
585	struct nand_chip *nand = mtd->priv;
586	struct docg4_priv *doc = nand->priv;
587	void __iomem *docptr = doc->virtadr;
588
589	writew(DOC_CTRL_UNKNOWN | DOC_CTRL_CE, docptr + DOC_FLASHCONTROL);
590	writew(DOC_SEQ_RESET, docptr + DOC_FLASHSEQUENCE);
591	writew(DOC_CMD_RESET, docptr + DOC_FLASHCOMMAND);
592	write_nop(docptr);
593	write_nop(docptr);
594	poll_status(doc);
595	write_nop(docptr);
596}
597
598static void read_page_prologue(struct mtd_info *mtd, uint32_t docg4_addr)
599{
600	/* first step in reading a page */
601
602	struct nand_chip *nand = mtd->priv;
603	struct docg4_priv *doc = nand->priv;
604	void __iomem *docptr = doc->virtadr;
605
606	dev_dbg(doc->dev,
607	      "docg4: %s: g4 page %08x\n", __func__, docg4_addr);
608
609	sequence_reset(mtd);
610
611	writew(DOCG4_SEQ_PAGE_READ, docptr + DOC_FLASHSEQUENCE);
612	writew(DOCG4_CMD_PAGE_READ, docptr + DOC_FLASHCOMMAND);
613	write_nop(docptr);
614
615	write_addr(doc, docg4_addr);
616
617	write_nop(docptr);
618	writew(DOCG4_CMD_READ2, docptr + DOC_FLASHCOMMAND);
619	write_nop(docptr);
620	write_nop(docptr);
621
622	poll_status(doc);
623}
624
625static void write_page_prologue(struct mtd_info *mtd, uint32_t docg4_addr)
626{
627	/* first step in writing a page */
628
629	struct nand_chip *nand = mtd->priv;
630	struct docg4_priv *doc = nand->priv;
631	void __iomem *docptr = doc->virtadr;
632
633	dev_dbg(doc->dev,
634	      "docg4: %s: g4 addr: %x\n", __func__, docg4_addr);
635	sequence_reset(mtd);
636
637	if (unlikely(reliable_mode)) {
638		writew(DOCG4_SEQ_SETMODE, docptr + DOC_FLASHSEQUENCE);
639		writew(DOCG4_CMD_FAST_MODE, docptr + DOC_FLASHCOMMAND);
640		writew(DOC_CMD_RELIABLE_MODE, docptr + DOC_FLASHCOMMAND);
641		write_nop(docptr);
642	}
643
644	writew(DOCG4_SEQ_PAGEWRITE, docptr + DOC_FLASHSEQUENCE);
645	writew(DOCG4_CMD_PAGEWRITE, docptr + DOC_FLASHCOMMAND);
646	write_nop(docptr);
647	write_addr(doc, docg4_addr);
648	write_nop(docptr);
649	write_nop(docptr);
650	poll_status(doc);
651}
652
653static uint32_t mtd_to_docg4_address(int page, int column)
654{
655	/*
656	 * Convert mtd address to format used by the device, 32 bit packed.
657	 *
658	 * Some notes on G4 addressing... The M-Sys documentation on this device
659	 * claims that pages are 2K in length, and indeed, the format of the
660	 * address used by the device reflects that.  But within each page are
661	 * four 512 byte "sub-pages", each with its own oob data that is
662	 * read/written immediately after the 512 bytes of page data.  This oob
663	 * data contains the ecc bytes for the preceeding 512 bytes.
664	 *
665	 * Rather than tell the mtd nand infrastructure that page size is 2k,
666	 * with four sub-pages each, we engage in a little subterfuge and tell
667	 * the infrastructure code that pages are 512 bytes in size.  This is
668	 * done because during the course of reverse-engineering the device, I
669	 * never observed an instance where an entire 2K "page" was read or
670	 * written as a unit.  Each "sub-page" is always addressed individually,
671	 * its data read/written, and ecc handled before the next "sub-page" is
672	 * addressed.
673	 *
674	 * This requires us to convert addresses passed by the mtd nand
675	 * infrastructure code to those used by the device.
676	 *
677	 * The address that is written to the device consists of four bytes: the
678	 * first two are the 2k page number, and the second is the index into
679	 * the page.  The index is in terms of 16-bit half-words and includes
680	 * the preceeding oob data, so e.g., the index into the second
681	 * "sub-page" is 0x108, and the full device address of the start of mtd
682	 * page 0x201 is 0x00800108.
683	 */
684	int g4_page = page / 4;	                      /* device's 2K page */
685	int g4_index = (page % 4) * 0x108 + column/2; /* offset into page */
686	return (g4_page << 16) | g4_index;	      /* pack */
687}
688
689static void docg4_command(struct mtd_info *mtd, unsigned command, int column,
690			  int page_addr)
691{
692	/* handle standard nand commands */
693
694	struct nand_chip *nand = mtd->priv;
695	struct docg4_priv *doc = nand->priv;
696	uint32_t g4_addr = mtd_to_docg4_address(page_addr, column);
697
698	dev_dbg(doc->dev, "%s %x, page_addr=%x, column=%x\n",
699	      __func__, command, page_addr, column);
700
701	/*
702	 * Save the command and its arguments.  This enables emulation of
703	 * standard flash devices, and also some optimizations.
704	 */
705	doc->last_command.command = command;
706	doc->last_command.column = column;
707	doc->last_command.page = page_addr;
708
709	switch (command) {
710
711	case NAND_CMD_RESET:
712		reset(mtd);
713		break;
714
715	case NAND_CMD_READ0:
716		read_page_prologue(mtd, g4_addr);
717		break;
718
719	case NAND_CMD_STATUS:
720		/* next call to read_byte() will expect a status */
721		break;
722
723	case NAND_CMD_SEQIN:
724		if (unlikely(reliable_mode)) {
725			uint16_t g4_page = g4_addr >> 16;
726
727			/* writes to odd-numbered 2k pages are invalid */
728			if (g4_page & 0x01)
729				dev_warn(doc->dev,
730					 "invalid reliable mode address\n");
731		}
732
733		write_page_prologue(mtd, g4_addr);
734
735		/* hack for deferred write of oob bytes */
736		if (doc->oob_page == page_addr)
737			memcpy(nand->oob_poi, doc->oob_buf, 16);
738		break;
739
740	case NAND_CMD_PAGEPROG:
741		pageprog(mtd);
742		break;
743
744	/* we don't expect these, based on review of nand_base.c */
745	case NAND_CMD_READOOB:
746	case NAND_CMD_READID:
747	case NAND_CMD_ERASE1:
748	case NAND_CMD_ERASE2:
749		dev_warn(doc->dev, "docg4_command: "
750			 "unexpected nand command 0x%x\n", command);
751		break;
752
753	}
754}
755
756static int read_page(struct mtd_info *mtd, struct nand_chip *nand,
757		     uint8_t *buf, int page, bool use_ecc)
758{
759	struct docg4_priv *doc = nand->priv;
760	void __iomem *docptr = doc->virtadr;
761	uint16_t status, edc_err, *buf16;
762	int bits_corrected = 0;
763
764	dev_dbg(doc->dev, "%s: page %08x\n", __func__, page);
765
766	writew(DOC_ECCCONF0_READ_MODE |
767	       DOC_ECCCONF0_ECC_ENABLE |
768	       DOC_ECCCONF0_UNKNOWN |
769	       DOCG4_BCH_SIZE,
770	       docptr + DOC_ECCCONF0);
771	write_nop(docptr);
772	write_nop(docptr);
773	write_nop(docptr);
774	write_nop(docptr);
775	write_nop(docptr);
776
777	/* the 1st byte from the I/O reg is a status; the rest is page data */
778	status = readw(docptr + DOC_IOSPACE_DATA);
779	if (status & DOCG4_READ_ERROR) {
780		dev_err(doc->dev,
781			"docg4_read_page: bad status: 0x%02x\n", status);
782		writew(0, docptr + DOC_DATAEND);
783		return -EIO;
784	}
785
786	dev_dbg(doc->dev, "%s: status = 0x%x\n", __func__, status);
787
788	docg4_read_buf(mtd, buf, DOCG4_PAGE_SIZE); /* read the page data */
789
790	/* this device always reads oob after page data */
791	/* first 14 oob bytes read from I/O reg */
792	docg4_read_buf(mtd, nand->oob_poi, 14);
793
794	/* last 2 read from another reg */
795	buf16 = (uint16_t *)(nand->oob_poi + 14);
796	*buf16 = readw(docptr + DOCG4_MYSTERY_REG);
797
798	write_nop(docptr);
799
800	if (likely(use_ecc == true)) {
801
802		/* read the register that tells us if bitflip(s) detected  */
803		edc_err = readw(docptr + DOC_ECCCONF1);
804		edc_err = readw(docptr + DOC_ECCCONF1);
805		dev_dbg(doc->dev, "%s: edc_err = 0x%02x\n", __func__, edc_err);
806
807		/* If bitflips are reported, attempt to correct with ecc */
808		if (edc_err & DOC_ECCCONF1_BCH_SYNDROM_ERR) {
809			bits_corrected = correct_data(mtd, buf, page);
810			if (bits_corrected == -EBADMSG)
811				mtd->ecc_stats.failed++;
812			else
813				mtd->ecc_stats.corrected += bits_corrected;
814		}
815	}
816
817	writew(0, docptr + DOC_DATAEND);
818	if (bits_corrected == -EBADMSG)	  /* uncorrectable errors */
819		return 0;
820	return bits_corrected;
821}
822
823
824static int docg4_read_page_raw(struct mtd_info *mtd, struct nand_chip *nand,
825			       uint8_t *buf, int oob_required, int page)
826{
827	return read_page(mtd, nand, buf, page, false);
828}
829
830static int docg4_read_page(struct mtd_info *mtd, struct nand_chip *nand,
831			   uint8_t *buf, int oob_required, int page)
832{
833	return read_page(mtd, nand, buf, page, true);
834}
835
836static int docg4_read_oob(struct mtd_info *mtd, struct nand_chip *nand,
837			  int page)
838{
839	struct docg4_priv *doc = nand->priv;
840	void __iomem *docptr = doc->virtadr;
841	uint16_t status;
842
843	dev_dbg(doc->dev, "%s: page %x\n", __func__, page);
844
845	docg4_command(mtd, NAND_CMD_READ0, nand->ecc.size, page);
846
847	writew(DOC_ECCCONF0_READ_MODE | DOCG4_OOB_SIZE, docptr + DOC_ECCCONF0);
848	write_nop(docptr);
849	write_nop(docptr);
850	write_nop(docptr);
851	write_nop(docptr);
852	write_nop(docptr);
853
854	/* the 1st byte from the I/O reg is a status; the rest is oob data */
855	status = readw(docptr + DOC_IOSPACE_DATA);
856	if (status & DOCG4_READ_ERROR) {
857		dev_warn(doc->dev,
858			 "docg4_read_oob failed: status = 0x%02x\n", status);
859		return -EIO;
860	}
861
862	dev_dbg(doc->dev, "%s: status = 0x%x\n", __func__, status);
863
864	docg4_read_buf(mtd, nand->oob_poi, 16);
865
866	write_nop(docptr);
867	write_nop(docptr);
868	write_nop(docptr);
869	writew(0, docptr + DOC_DATAEND);
870	write_nop(docptr);
871
872	return 0;
873}
874
875static int docg4_erase_block(struct mtd_info *mtd, int page)
876{
877	struct nand_chip *nand = mtd->priv;
878	struct docg4_priv *doc = nand->priv;
879	void __iomem *docptr = doc->virtadr;
880	uint16_t g4_page;
881
882	dev_dbg(doc->dev, "%s: page %04x\n", __func__, page);
883
884	sequence_reset(mtd);
885
886	writew(DOCG4_SEQ_BLOCKERASE, docptr + DOC_FLASHSEQUENCE);
887	writew(DOC_CMD_PROG_BLOCK_ADDR, docptr + DOC_FLASHCOMMAND);
888	write_nop(docptr);
889
890	/* only 2 bytes of address are written to specify erase block */
891	g4_page = (uint16_t)(page / 4);  /* to g4's 2k page addressing */
892	writeb(g4_page & 0xff, docptr + DOC_FLASHADDRESS);
893	g4_page >>= 8;
894	writeb(g4_page & 0xff, docptr + DOC_FLASHADDRESS);
895	write_nop(docptr);
896
897	/* start the erasure */
898	writew(DOC_CMD_ERASECYCLE2, docptr + DOC_FLASHCOMMAND);
899	write_nop(docptr);
900	write_nop(docptr);
901
902	usleep_range(500, 1000); /* erasure is long; take a snooze */
903	poll_status(doc);
904	writew(DOCG4_SEQ_FLUSH, docptr + DOC_FLASHSEQUENCE);
905	writew(DOCG4_CMD_FLUSH, docptr + DOC_FLASHCOMMAND);
906	writew(DOC_ECCCONF0_READ_MODE | 4, docptr + DOC_ECCCONF0);
907	write_nop(docptr);
908	write_nop(docptr);
909	write_nop(docptr);
910	write_nop(docptr);
911	write_nop(docptr);
912
913	read_progstatus(doc);
914
915	writew(0, docptr + DOC_DATAEND);
916	write_nop(docptr);
917	poll_status(doc);
918	write_nop(docptr);
919
920	return nand->waitfunc(mtd, nand);
921}
922
923static int write_page(struct mtd_info *mtd, struct nand_chip *nand,
924		       const uint8_t *buf, bool use_ecc)
925{
926	struct docg4_priv *doc = nand->priv;
927	void __iomem *docptr = doc->virtadr;
928	uint8_t ecc_buf[8];
929
930	dev_dbg(doc->dev, "%s...\n", __func__);
931
932	writew(DOC_ECCCONF0_ECC_ENABLE |
933	       DOC_ECCCONF0_UNKNOWN |
934	       DOCG4_BCH_SIZE,
935	       docptr + DOC_ECCCONF0);
936	write_nop(docptr);
937
938	/* write the page data */
939	docg4_write_buf16(mtd, buf, DOCG4_PAGE_SIZE);
940
941	/* oob bytes 0 through 5 are written to I/O reg */
942	docg4_write_buf16(mtd, nand->oob_poi, 6);
943
944	/* oob byte 6 written to a separate reg */
945	writew(nand->oob_poi[6], docptr + DOCG4_OOB_6_7);
946
947	write_nop(docptr);
948	write_nop(docptr);
949
950	/* write hw-generated ecc bytes to oob */
951	if (likely(use_ecc == true)) {
952		/* oob byte 7 is hamming code */
953		uint8_t hamming = readb(docptr + DOC_HAMMINGPARITY);
954		hamming = readb(docptr + DOC_HAMMINGPARITY); /* 2nd read */
955		writew(hamming, docptr + DOCG4_OOB_6_7);
956		write_nop(docptr);
957
958		/* read the 7 bch bytes from ecc regs */
959		read_hw_ecc(docptr, ecc_buf);
960		ecc_buf[7] = 0;         /* clear the "page written" flag */
961	}
962
963	/* write user-supplied bytes to oob */
964	else {
965		writew(nand->oob_poi[7], docptr + DOCG4_OOB_6_7);
966		write_nop(docptr);
967		memcpy(ecc_buf, &nand->oob_poi[8], 8);
968	}
969
970	docg4_write_buf16(mtd, ecc_buf, 8);
971	write_nop(docptr);
972	write_nop(docptr);
973	writew(0, docptr + DOC_DATAEND);
974	write_nop(docptr);
975
976	return 0;
977}
978
979static int docg4_write_page_raw(struct mtd_info *mtd, struct nand_chip *nand,
980				 const uint8_t *buf, int oob_required)
981{
982	return write_page(mtd, nand, buf, false);
983}
984
985static int docg4_write_page(struct mtd_info *mtd, struct nand_chip *nand,
986			     const uint8_t *buf, int oob_required)
987{
988	return write_page(mtd, nand, buf, true);
989}
990
991static int docg4_write_oob(struct mtd_info *mtd, struct nand_chip *nand,
992			   int page)
993{
994	/*
995	 * Writing oob-only is not really supported, because MLC nand must write
996	 * oob bytes at the same time as page data.  Nonetheless, we save the
997	 * oob buffer contents here, and then write it along with the page data
998	 * if the same page is subsequently written.  This allows user space
999	 * utilities that write the oob data prior to the page data to work
1000	 * (e.g., nandwrite).  The disdvantage is that, if the intention was to
1001	 * write oob only, the operation is quietly ignored.  Also, oob can get
1002	 * corrupted if two concurrent processes are running nandwrite.
1003	 */
1004
1005	/* note that bytes 7..14 are hw generated hamming/ecc and overwritten */
1006	struct docg4_priv *doc = nand->priv;
1007	doc->oob_page = page;
1008	memcpy(doc->oob_buf, nand->oob_poi, 16);
1009	return 0;
1010}
1011
1012static int __init read_factory_bbt(struct mtd_info *mtd)
1013{
1014	/*
1015	 * The device contains a read-only factory bad block table.  Read it and
1016	 * update the memory-based bbt accordingly.
1017	 */
1018
1019	struct nand_chip *nand = mtd->priv;
1020	struct docg4_priv *doc = nand->priv;
1021	uint32_t g4_addr = mtd_to_docg4_address(DOCG4_FACTORY_BBT_PAGE, 0);
1022	uint8_t *buf;
1023	int i, block;
1024	__u32 eccfailed_stats = mtd->ecc_stats.failed;
1025
1026	buf = kzalloc(DOCG4_PAGE_SIZE, GFP_KERNEL);
1027	if (buf == NULL)
1028		return -ENOMEM;
1029
1030	read_page_prologue(mtd, g4_addr);
1031	docg4_read_page(mtd, nand, buf, 0, DOCG4_FACTORY_BBT_PAGE);
1032
1033	/*
1034	 * If no memory-based bbt was created, exit.  This will happen if module
1035	 * parameter ignore_badblocks is set.  Then why even call this function?
1036	 * For an unknown reason, block erase always fails if it's the first
1037	 * operation after device power-up.  The above read ensures it never is.
1038	 * Ugly, I know.
1039	 */
1040	if (nand->bbt == NULL)  /* no memory-based bbt */
1041		goto exit;
1042
1043	if (mtd->ecc_stats.failed > eccfailed_stats) {
1044		/*
1045		 * Whoops, an ecc failure ocurred reading the factory bbt.
1046		 * It is stored redundantly, so we get another chance.
1047		 */
1048		eccfailed_stats = mtd->ecc_stats.failed;
1049		docg4_read_page(mtd, nand, buf, 0, DOCG4_REDUNDANT_BBT_PAGE);
1050		if (mtd->ecc_stats.failed > eccfailed_stats) {
1051			dev_warn(doc->dev,
1052				 "The factory bbt could not be read!\n");
1053			goto exit;
1054		}
1055	}
1056
1057	/*
1058	 * Parse factory bbt and update memory-based bbt.  Factory bbt format is
1059	 * simple: one bit per block, block numbers increase left to right (msb
1060	 * to lsb).  Bit clear means bad block.
1061	 */
1062	for (i = block = 0; block < DOCG4_NUMBLOCKS; block += 8, i++) {
1063		int bitnum;
1064		unsigned long bits = ~buf[i];
1065		for_each_set_bit(bitnum, &bits, 8) {
1066			int badblock = block + 7 - bitnum;
1067			nand->bbt[badblock / 4] |=
1068				0x03 << ((badblock % 4) * 2);
1069			mtd->ecc_stats.badblocks++;
1070			dev_notice(doc->dev, "factory-marked bad block: %d\n",
1071				   badblock);
1072		}
1073	}
1074 exit:
1075	kfree(buf);
1076	return 0;
1077}
1078
1079static int docg4_block_markbad(struct mtd_info *mtd, loff_t ofs)
1080{
1081	/*
1082	 * Mark a block as bad.  Bad blocks are marked in the oob area of the
1083	 * first page of the block.  The default scan_bbt() in the nand
1084	 * infrastructure code works fine for building the memory-based bbt
1085	 * during initialization, as does the nand infrastructure function that
1086	 * checks if a block is bad by reading the bbt.  This function replaces
1087	 * the nand default because writes to oob-only are not supported.
1088	 */
1089
1090	int ret, i;
1091	uint8_t *buf;
1092	struct nand_chip *nand = mtd->priv;
1093	struct docg4_priv *doc = nand->priv;
1094	struct nand_bbt_descr *bbtd = nand->badblock_pattern;
1095	int page = (int)(ofs >> nand->page_shift);
1096	uint32_t g4_addr = mtd_to_docg4_address(page, 0);
1097
1098	dev_dbg(doc->dev, "%s: %08llx\n", __func__, ofs);
1099
1100	if (unlikely(ofs & (DOCG4_BLOCK_SIZE - 1)))
1101		dev_warn(doc->dev, "%s: ofs %llx not start of block!\n",
1102			 __func__, ofs);
1103
1104	/* allocate blank buffer for page data */
1105	buf = kzalloc(DOCG4_PAGE_SIZE, GFP_KERNEL);
1106	if (buf == NULL)
1107		return -ENOMEM;
1108
1109	/* write bit-wise negation of pattern to oob buffer */
1110	memset(nand->oob_poi, 0xff, mtd->oobsize);
1111	for (i = 0; i < bbtd->len; i++)
1112		nand->oob_poi[bbtd->offs + i] = ~bbtd->pattern[i];
1113
1114	/* write first page of block */
1115	write_page_prologue(mtd, g4_addr);
1116	docg4_write_page(mtd, nand, buf, 1);
1117	ret = pageprog(mtd);
1118
1119	kfree(buf);
1120
1121	return ret;
1122}
1123
1124static int docg4_block_neverbad(struct mtd_info *mtd, loff_t ofs, int getchip)
1125{
1126	/* only called when module_param ignore_badblocks is set */
1127	return 0;
1128}
1129
1130static int docg4_suspend(struct platform_device *pdev, pm_message_t state)
1131{
1132	/*
1133	 * Put the device into "deep power-down" mode.  Note that CE# must be
1134	 * deasserted for this to take effect.  The xscale, e.g., can be
1135	 * configured to float this signal when the processor enters power-down,
1136	 * and a suitable pull-up ensures its deassertion.
1137	 */
1138
1139	int i;
1140	uint8_t pwr_down;
1141	struct docg4_priv *doc = platform_get_drvdata(pdev);
1142	void __iomem *docptr = doc->virtadr;
1143
1144	dev_dbg(doc->dev, "%s...\n", __func__);
1145
1146	/* poll the register that tells us we're ready to go to sleep */
1147	for (i = 0; i < 10; i++) {
1148		pwr_down = readb(docptr + DOC_POWERMODE);
1149		if (pwr_down & DOC_POWERDOWN_READY)
1150			break;
1151		usleep_range(1000, 4000);
1152	}
1153
1154	if (pwr_down & DOC_POWERDOWN_READY) {
1155		dev_err(doc->dev, "suspend failed; "
1156			"timeout polling DOC_POWERDOWN_READY\n");
1157		return -EIO;
1158	}
1159
1160	writew(DOC_ASICMODE_POWERDOWN | DOC_ASICMODE_MDWREN,
1161	       docptr + DOC_ASICMODE);
1162	writew(~(DOC_ASICMODE_POWERDOWN | DOC_ASICMODE_MDWREN),
1163	       docptr + DOC_ASICMODECONFIRM);
1164
1165	write_nop(docptr);
1166
1167	return 0;
1168}
1169
1170static int docg4_resume(struct platform_device *pdev)
1171{
1172
1173	/*
1174	 * Exit power-down.  Twelve consecutive reads of the address below
1175	 * accomplishes this, assuming CE# has been asserted.
1176	 */
1177
1178	struct docg4_priv *doc = platform_get_drvdata(pdev);
1179	void __iomem *docptr = doc->virtadr;
1180	int i;
1181
1182	dev_dbg(doc->dev, "%s...\n", __func__);
1183
1184	for (i = 0; i < 12; i++)
1185		readb(docptr + 0x1fff);
1186
1187	return 0;
1188}
1189
1190static void __init init_mtd_structs(struct mtd_info *mtd)
1191{
1192	/* initialize mtd and nand data structures */
1193
1194	/*
1195	 * Note that some of the following initializations are not usually
1196	 * required within a nand driver because they are performed by the nand
1197	 * infrastructure code as part of nand_scan().  In this case they need
1198	 * to be initialized here because we skip call to nand_scan_ident() (the
1199	 * first half of nand_scan()).  The call to nand_scan_ident() is skipped
1200	 * because for this device the chip id is not read in the manner of a
1201	 * standard nand device.  Unfortunately, nand_scan_ident() does other
1202	 * things as well, such as call nand_set_defaults().
1203	 */
1204
1205	struct nand_chip *nand = mtd->priv;
1206	struct docg4_priv *doc = nand->priv;
1207
1208	mtd->size = DOCG4_CHIP_SIZE;
1209	mtd->name = "Msys_Diskonchip_G4";
1210	mtd->writesize = DOCG4_PAGE_SIZE;
1211	mtd->erasesize = DOCG4_BLOCK_SIZE;
1212	mtd->oobsize = DOCG4_OOB_SIZE;
1213	nand->chipsize = DOCG4_CHIP_SIZE;
1214	nand->chip_shift = DOCG4_CHIP_SHIFT;
1215	nand->bbt_erase_shift = nand->phys_erase_shift = DOCG4_ERASE_SHIFT;
1216	nand->chip_delay = 20;
1217	nand->page_shift = DOCG4_PAGE_SHIFT;
1218	nand->pagemask = 0x3ffff;
1219	nand->badblockpos = NAND_LARGE_BADBLOCK_POS;
1220	nand->badblockbits = 8;
1221	nand->ecc.layout = &docg4_oobinfo;
1222	nand->ecc.mode = NAND_ECC_HW_SYNDROME;
1223	nand->ecc.size = DOCG4_PAGE_SIZE;
1224	nand->ecc.prepad = 8;
1225	nand->ecc.bytes	= 8;
1226	nand->ecc.strength = DOCG4_T;
1227	nand->options = NAND_BUSWIDTH_16 | NAND_NO_SUBPAGE_WRITE;
1228	nand->IO_ADDR_R = nand->IO_ADDR_W = doc->virtadr + DOC_IOSPACE_DATA;
1229	nand->controller = &nand->hwcontrol;
1230	spin_lock_init(&nand->controller->lock);
1231	init_waitqueue_head(&nand->controller->wq);
1232
1233	/* methods */
1234	nand->cmdfunc = docg4_command;
1235	nand->waitfunc = docg4_wait;
1236	nand->select_chip = docg4_select_chip;
1237	nand->read_byte = docg4_read_byte;
1238	nand->block_markbad = docg4_block_markbad;
1239	nand->read_buf = docg4_read_buf;
1240	nand->write_buf = docg4_write_buf16;
1241	nand->erase = docg4_erase_block;
1242	nand->ecc.read_page = docg4_read_page;
1243	nand->ecc.write_page = docg4_write_page;
1244	nand->ecc.read_page_raw = docg4_read_page_raw;
1245	nand->ecc.write_page_raw = docg4_write_page_raw;
1246	nand->ecc.read_oob = docg4_read_oob;
1247	nand->ecc.write_oob = docg4_write_oob;
1248
1249	/*
1250	 * The way the nand infrastructure code is written, a memory-based bbt
1251	 * is not created if NAND_SKIP_BBTSCAN is set.  With no memory bbt,
1252	 * nand->block_bad() is used.  So when ignoring bad blocks, we skip the
1253	 * scan and define a dummy block_bad() which always returns 0.
1254	 */
1255	if (ignore_badblocks) {
1256		nand->options |= NAND_SKIP_BBTSCAN;
1257		nand->block_bad	= docg4_block_neverbad;
1258	}
1259
1260}
1261
1262static int __init read_id_reg(struct mtd_info *mtd)
1263{
1264	struct nand_chip *nand = mtd->priv;
1265	struct docg4_priv *doc = nand->priv;
1266	void __iomem *docptr = doc->virtadr;
1267	uint16_t id1, id2;
1268
1269	/* check for presence of g4 chip by reading id registers */
1270	id1 = readw(docptr + DOC_CHIPID);
1271	id1 = readw(docptr + DOCG4_MYSTERY_REG);
1272	id2 = readw(docptr + DOC_CHIPID_INV);
1273	id2 = readw(docptr + DOCG4_MYSTERY_REG);
1274
1275	if (id1 == DOCG4_IDREG1_VALUE && id2 == DOCG4_IDREG2_VALUE) {
1276		dev_info(doc->dev,
1277			 "NAND device: 128MiB Diskonchip G4 detected\n");
1278		return 0;
1279	}
1280
1281	return -ENODEV;
1282}
1283
1284static char const *part_probes[] = { "cmdlinepart", "saftlpart", NULL };
1285
1286static int __init probe_docg4(struct platform_device *pdev)
1287{
1288	struct mtd_info *mtd;
1289	struct nand_chip *nand;
1290	void __iomem *virtadr;
1291	struct docg4_priv *doc;
1292	int len, retval;
1293	struct resource *r;
1294	struct device *dev = &pdev->dev;
1295
1296	r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
1297	if (r == NULL) {
1298		dev_err(dev, "no io memory resource defined!\n");
1299		return -ENODEV;
1300	}
1301
1302	virtadr = ioremap(r->start, resource_size(r));
1303	if (!virtadr) {
1304		dev_err(dev, "Diskonchip ioremap failed: %pR\n", r);
1305		return -EIO;
1306	}
1307
1308	len = sizeof(struct mtd_info) + sizeof(struct nand_chip) +
1309		sizeof(struct docg4_priv);
1310	mtd = kzalloc(len, GFP_KERNEL);
1311	if (mtd == NULL) {
1312		retval = -ENOMEM;
1313		goto fail;
1314	}
1315	nand = (struct nand_chip *) (mtd + 1);
1316	doc = (struct docg4_priv *) (nand + 1);
1317	mtd->priv = nand;
1318	nand->priv = doc;
1319	mtd->owner = THIS_MODULE;
1320	doc->virtadr = virtadr;
1321	doc->dev = dev;
1322
1323	init_mtd_structs(mtd);
1324
1325	/* initialize kernel bch algorithm */
1326	doc->bch = init_bch(DOCG4_M, DOCG4_T, DOCG4_PRIMITIVE_POLY);
1327	if (doc->bch == NULL) {
1328		retval = -EINVAL;
1329		goto fail;
1330	}
1331
1332	platform_set_drvdata(pdev, doc);
1333
1334	reset(mtd);
1335	retval = read_id_reg(mtd);
1336	if (retval == -ENODEV) {
1337		dev_warn(dev, "No diskonchip G4 device found.\n");
1338		goto fail;
1339	}
1340
1341	retval = nand_scan_tail(mtd);
1342	if (retval)
1343		goto fail;
1344
1345	retval = read_factory_bbt(mtd);
1346	if (retval)
1347		goto fail;
1348
1349	retval = mtd_device_parse_register(mtd, part_probes, NULL, NULL, 0);
1350	if (retval)
1351		goto fail;
1352
1353	doc->mtd = mtd;
1354	return 0;
1355
1356 fail:
1357	iounmap(virtadr);
1358	if (mtd) {
1359		/* re-declarations avoid compiler warning */
1360		struct nand_chip *nand = mtd->priv;
1361		struct docg4_priv *doc = nand->priv;
1362		nand_release(mtd); /* deletes partitions and mtd devices */
1363		free_bch(doc->bch);
1364		kfree(mtd);
1365	}
1366
1367	return retval;
1368}
1369
1370static int __exit cleanup_docg4(struct platform_device *pdev)
1371{
1372	struct docg4_priv *doc = platform_get_drvdata(pdev);
1373	nand_release(doc->mtd);
1374	free_bch(doc->bch);
1375	kfree(doc->mtd);
1376	iounmap(doc->virtadr);
1377	return 0;
1378}
1379
1380static struct platform_driver docg4_driver = {
1381	.driver		= {
1382		.name	= "docg4",
1383	},
1384	.suspend	= docg4_suspend,
1385	.resume		= docg4_resume,
1386	.remove		= __exit_p(cleanup_docg4),
1387};
1388
1389module_platform_driver_probe(docg4_driver, probe_docg4);
1390
1391MODULE_LICENSE("GPL");
1392MODULE_AUTHOR("Mike Dunn");
1393MODULE_DESCRIPTION("M-Systems DiskOnChip G4 device driver");
1394