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Linux/drivers/mtd/nand/docg4.c

  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  */
 64 static bool reliable_mode;
 65 module_param(reliable_mode, bool, 0);
 66 MODULE_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  */
 74 static bool ignore_badblocks;
 75 module_param(ignore_badblocks, bool, 0);
 76 MODULE_PARM_DESC(ignore_badblocks, "no badblock checking performed");
 77 
 78 struct 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  */
225 static int docg4_ooblayout_ecc(struct mtd_info *mtd, int section,
226                                struct mtd_oob_region *oobregion)
227 {
228         if (section)
229                 return -ERANGE;
230 
231         oobregion->offset = 7;
232         oobregion->length = 9;
233 
234         return 0;
235 }
236 
237 static int docg4_ooblayout_free(struct mtd_info *mtd, int section,
238                                 struct mtd_oob_region *oobregion)
239 {
240         if (section)
241                 return -ERANGE;
242 
243         oobregion->offset = 2;
244         oobregion->length = 5;
245 
246         return 0;
247 }
248 
249 static const struct mtd_ooblayout_ops docg4_ooblayout_ops = {
250         .ecc = docg4_ooblayout_ecc,
251         .free = docg4_ooblayout_free,
252 };
253 
254 /*
255  * The device has a nop register which M-Sys claims is for the purpose of
256  * inserting precise delays.  But beware; at least some operations fail if the
257  * nop writes are replaced with a generic delay!
258  */
259 static inline void write_nop(void __iomem *docptr)
260 {
261         writew(0, docptr + DOC_NOP);
262 }
263 
264 static void docg4_read_buf(struct mtd_info *mtd, uint8_t *buf, int len)
265 {
266         int i;
267         struct nand_chip *nand = mtd_to_nand(mtd);
268         uint16_t *p = (uint16_t *) buf;
269         len >>= 1;
270 
271         for (i = 0; i < len; i++)
272                 p[i] = readw(nand->IO_ADDR_R);
273 }
274 
275 static void docg4_write_buf16(struct mtd_info *mtd, const uint8_t *buf, int len)
276 {
277         int i;
278         struct nand_chip *nand = mtd_to_nand(mtd);
279         uint16_t *p = (uint16_t *) buf;
280         len >>= 1;
281 
282         for (i = 0; i < len; i++)
283                 writew(p[i], nand->IO_ADDR_W);
284 }
285 
286 static int poll_status(struct docg4_priv *doc)
287 {
288         /*
289          * Busy-wait for the FLASHREADY bit to be set in the FLASHCONTROL
290          * register.  Operations known to take a long time (e.g., block erase)
291          * should sleep for a while before calling this.
292          */
293 
294         uint16_t flash_status;
295         unsigned long timeo;
296         void __iomem *docptr = doc->virtadr;
297 
298         dev_dbg(doc->dev, "%s...\n", __func__);
299 
300         /* hardware quirk requires reading twice initially */
301         flash_status = readw(docptr + DOC_FLASHCONTROL);
302 
303         timeo = jiffies + msecs_to_jiffies(200); /* generous timeout */
304         do {
305                 cpu_relax();
306                 flash_status = readb(docptr + DOC_FLASHCONTROL);
307         } while (!(flash_status & DOC_CTRL_FLASHREADY) &&
308                  time_before(jiffies, timeo));
309 
310         if (unlikely(!(flash_status & DOC_CTRL_FLASHREADY))) {
311                 dev_err(doc->dev, "%s: timed out!\n", __func__);
312                 return NAND_STATUS_FAIL;
313         }
314 
315         return 0;
316 }
317 
318 
319 static int docg4_wait(struct mtd_info *mtd, struct nand_chip *nand)
320 {
321 
322         struct docg4_priv *doc = nand_get_controller_data(nand);
323         int status = NAND_STATUS_WP;       /* inverse logic?? */
324         dev_dbg(doc->dev, "%s...\n", __func__);
325 
326         /* report any previously unreported error */
327         if (doc->status) {
328                 status |= doc->status;
329                 doc->status = 0;
330                 return status;
331         }
332 
333         status |= poll_status(doc);
334         return status;
335 }
336 
337 static void docg4_select_chip(struct mtd_info *mtd, int chip)
338 {
339         /*
340          * Select among multiple cascaded chips ("floors").  Multiple floors are
341          * not yet supported, so the only valid non-negative value is 0.
342          */
343         struct nand_chip *nand = mtd_to_nand(mtd);
344         struct docg4_priv *doc = nand_get_controller_data(nand);
345         void __iomem *docptr = doc->virtadr;
346 
347         dev_dbg(doc->dev, "%s: chip %d\n", __func__, chip);
348 
349         if (chip < 0)
350                 return;         /* deselected */
351 
352         if (chip > 0)
353                 dev_warn(doc->dev, "multiple floors currently unsupported\n");
354 
355         writew(0, docptr + DOC_DEVICESELECT);
356 }
357 
358 static void reset(struct mtd_info *mtd)
359 {
360         /* full device reset */
361 
362         struct nand_chip *nand = mtd_to_nand(mtd);
363         struct docg4_priv *doc = nand_get_controller_data(nand);
364         void __iomem *docptr = doc->virtadr;
365 
366         writew(DOC_ASICMODE_RESET | DOC_ASICMODE_MDWREN,
367                docptr + DOC_ASICMODE);
368         writew(~(DOC_ASICMODE_RESET | DOC_ASICMODE_MDWREN),
369                docptr + DOC_ASICMODECONFIRM);
370         write_nop(docptr);
371 
372         writew(DOC_ASICMODE_NORMAL | DOC_ASICMODE_MDWREN,
373                docptr + DOC_ASICMODE);
374         writew(~(DOC_ASICMODE_NORMAL | DOC_ASICMODE_MDWREN),
375                docptr + DOC_ASICMODECONFIRM);
376 
377         writew(DOC_ECCCONF1_ECC_ENABLE, docptr + DOC_ECCCONF1);
378 
379         poll_status(doc);
380 }
381 
382 static void read_hw_ecc(void __iomem *docptr, uint8_t *ecc_buf)
383 {
384         /* read the 7 hw-generated ecc bytes */
385 
386         int i;
387         for (i = 0; i < 7; i++) { /* hw quirk; read twice */
388                 ecc_buf[i] = readb(docptr + DOC_BCH_SYNDROM(i));
389                 ecc_buf[i] = readb(docptr + DOC_BCH_SYNDROM(i));
390         }
391 }
392 
393 static int correct_data(struct mtd_info *mtd, uint8_t *buf, int page)
394 {
395         /*
396          * Called after a page read when hardware reports bitflips.
397          * Up to four bitflips can be corrected.
398          */
399 
400         struct nand_chip *nand = mtd_to_nand(mtd);
401         struct docg4_priv *doc = nand_get_controller_data(nand);
402         void __iomem *docptr = doc->virtadr;
403         int i, numerrs, errpos[4];
404         const uint8_t blank_read_hwecc[8] = {
405                 0xcf, 0x72, 0xfc, 0x1b, 0xa9, 0xc7, 0xb9, 0 };
406 
407         read_hw_ecc(docptr, doc->ecc_buf); /* read 7 hw-generated ecc bytes */
408 
409         /* check if read error is due to a blank page */
410         if (!memcmp(doc->ecc_buf, blank_read_hwecc, 7))
411                 return 0;       /* yes */
412 
413         /* skip additional check of "written flag" if ignore_badblocks */
414         if (ignore_badblocks == false) {
415 
416                 /*
417                  * If the hw ecc bytes are not those of a blank page, there's
418                  * still a chance that the page is blank, but was read with
419                  * errors.  Check the "written flag" in last oob byte, which
420                  * is set to zero when a page is written.  If more than half
421                  * the bits are set, assume a blank page.  Unfortunately, the
422                  * bit flips(s) are not reported in stats.
423                  */
424 
425                 if (nand->oob_poi[15]) {
426                         int bit, numsetbits = 0;
427                         unsigned long written_flag = nand->oob_poi[15];
428                         for_each_set_bit(bit, &written_flag, 8)
429                                 numsetbits++;
430                         if (numsetbits > 4) { /* assume blank */
431                                 dev_warn(doc->dev,
432                                          "error(s) in blank page "
433                                          "at offset %08x\n",
434                                          page * DOCG4_PAGE_SIZE);
435                                 return 0;
436                         }
437                 }
438         }
439 
440         /*
441          * The hardware ecc unit produces oob_ecc ^ calc_ecc.  The kernel's bch
442          * algorithm is used to decode this.  However the hw operates on page
443          * data in a bit order that is the reverse of that of the bch alg,
444          * requiring that the bits be reversed on the result.  Thanks to Ivan
445          * Djelic for his analysis!
446          */
447         for (i = 0; i < 7; i++)
448                 doc->ecc_buf[i] = bitrev8(doc->ecc_buf[i]);
449 
450         numerrs = decode_bch(doc->bch, NULL, DOCG4_USERDATA_LEN, NULL,
451                              doc->ecc_buf, NULL, errpos);
452 
453         if (numerrs == -EBADMSG) {
454                 dev_warn(doc->dev, "uncorrectable errors at offset %08x\n",
455                          page * DOCG4_PAGE_SIZE);
456                 return -EBADMSG;
457         }
458 
459         BUG_ON(numerrs < 0);    /* -EINVAL, or anything other than -EBADMSG */
460 
461         /* undo last step in BCH alg (modulo mirroring not needed) */
462         for (i = 0; i < numerrs; i++)
463                 errpos[i] = (errpos[i] & ~7)|(7-(errpos[i] & 7));
464 
465         /* fix the errors */
466         for (i = 0; i < numerrs; i++) {
467 
468                 /* ignore if error within oob ecc bytes */
469                 if (errpos[i] > DOCG4_USERDATA_LEN * 8)
470                         continue;
471 
472                 /* if error within oob area preceeding ecc bytes... */
473                 if (errpos[i] > DOCG4_PAGE_SIZE * 8)
474                         change_bit(errpos[i] - DOCG4_PAGE_SIZE * 8,
475                                    (unsigned long *)nand->oob_poi);
476 
477                 else    /* error in page data */
478                         change_bit(errpos[i], (unsigned long *)buf);
479         }
480 
481         dev_notice(doc->dev, "%d error(s) corrected at offset %08x\n",
482                    numerrs, page * DOCG4_PAGE_SIZE);
483 
484         return numerrs;
485 }
486 
487 static uint8_t docg4_read_byte(struct mtd_info *mtd)
488 {
489         struct nand_chip *nand = mtd_to_nand(mtd);
490         struct docg4_priv *doc = nand_get_controller_data(nand);
491 
492         dev_dbg(doc->dev, "%s\n", __func__);
493 
494         if (doc->last_command.command == NAND_CMD_STATUS) {
495                 int status;
496 
497                 /*
498                  * Previous nand command was status request, so nand
499                  * infrastructure code expects to read the status here.  If an
500                  * error occurred in a previous operation, report it.
501                  */
502                 doc->last_command.command = 0;
503 
504                 if (doc->status) {
505                         status = doc->status;
506                         doc->status = 0;
507                 }
508 
509                 /* why is NAND_STATUS_WP inverse logic?? */
510                 else
511                         status = NAND_STATUS_WP | NAND_STATUS_READY;
512 
513                 return status;
514         }
515 
516         dev_warn(doc->dev, "unexpected call to read_byte()\n");
517 
518         return 0;
519 }
520 
521 static void write_addr(struct docg4_priv *doc, uint32_t docg4_addr)
522 {
523         /* write the four address bytes packed in docg4_addr to the device */
524 
525         void __iomem *docptr = doc->virtadr;
526         writeb(docg4_addr & 0xff, docptr + DOC_FLASHADDRESS);
527         docg4_addr >>= 8;
528         writeb(docg4_addr & 0xff, docptr + DOC_FLASHADDRESS);
529         docg4_addr >>= 8;
530         writeb(docg4_addr & 0xff, docptr + DOC_FLASHADDRESS);
531         docg4_addr >>= 8;
532         writeb(docg4_addr & 0xff, docptr + DOC_FLASHADDRESS);
533 }
534 
535 static int read_progstatus(struct docg4_priv *doc)
536 {
537         /*
538          * This apparently checks the status of programming.  Done after an
539          * erasure, and after page data is written.  On error, the status is
540          * saved, to be later retrieved by the nand infrastructure code.
541          */
542         void __iomem *docptr = doc->virtadr;
543 
544         /* status is read from the I/O reg */
545         uint16_t status1 = readw(docptr + DOC_IOSPACE_DATA);
546         uint16_t status2 = readw(docptr + DOC_IOSPACE_DATA);
547         uint16_t status3 = readw(docptr + DOCG4_MYSTERY_REG);
548 
549         dev_dbg(doc->dev, "docg4: %s: %02x %02x %02x\n",
550               __func__, status1, status2, status3);
551 
552         if (status1 != DOCG4_PROGSTATUS_GOOD
553             || status2 != DOCG4_PROGSTATUS_GOOD_2
554             || status3 != DOCG4_PROGSTATUS_GOOD_2) {
555                 doc->status = NAND_STATUS_FAIL;
556                 dev_warn(doc->dev, "read_progstatus failed: "
557                          "%02x, %02x, %02x\n", status1, status2, status3);
558                 return -EIO;
559         }
560         return 0;
561 }
562 
563 static int pageprog(struct mtd_info *mtd)
564 {
565         /*
566          * Final step in writing a page.  Writes the contents of its
567          * internal buffer out to the flash array, or some such.
568          */
569 
570         struct nand_chip *nand = mtd_to_nand(mtd);
571         struct docg4_priv *doc = nand_get_controller_data(nand);
572         void __iomem *docptr = doc->virtadr;
573         int retval = 0;
574 
575         dev_dbg(doc->dev, "docg4: %s\n", __func__);
576 
577         writew(DOCG4_SEQ_PAGEPROG, docptr + DOC_FLASHSEQUENCE);
578         writew(DOC_CMD_PROG_CYCLE2, docptr + DOC_FLASHCOMMAND);
579         write_nop(docptr);
580         write_nop(docptr);
581 
582         /* Just busy-wait; usleep_range() slows things down noticeably. */
583         poll_status(doc);
584 
585         writew(DOCG4_SEQ_FLUSH, docptr + DOC_FLASHSEQUENCE);
586         writew(DOCG4_CMD_FLUSH, docptr + DOC_FLASHCOMMAND);
587         writew(DOC_ECCCONF0_READ_MODE | 4, docptr + DOC_ECCCONF0);
588         write_nop(docptr);
589         write_nop(docptr);
590         write_nop(docptr);
591         write_nop(docptr);
592         write_nop(docptr);
593 
594         retval = read_progstatus(doc);
595         writew(0, docptr + DOC_DATAEND);
596         write_nop(docptr);
597         poll_status(doc);
598         write_nop(docptr);
599 
600         return retval;
601 }
602 
603 static void sequence_reset(struct mtd_info *mtd)
604 {
605         /* common starting sequence for all operations */
606 
607         struct nand_chip *nand = mtd_to_nand(mtd);
608         struct docg4_priv *doc = nand_get_controller_data(nand);
609         void __iomem *docptr = doc->virtadr;
610 
611         writew(DOC_CTRL_UNKNOWN | DOC_CTRL_CE, docptr + DOC_FLASHCONTROL);
612         writew(DOC_SEQ_RESET, docptr + DOC_FLASHSEQUENCE);
613         writew(DOC_CMD_RESET, docptr + DOC_FLASHCOMMAND);
614         write_nop(docptr);
615         write_nop(docptr);
616         poll_status(doc);
617         write_nop(docptr);
618 }
619 
620 static void read_page_prologue(struct mtd_info *mtd, uint32_t docg4_addr)
621 {
622         /* first step in reading a page */
623 
624         struct nand_chip *nand = mtd_to_nand(mtd);
625         struct docg4_priv *doc = nand_get_controller_data(nand);
626         void __iomem *docptr = doc->virtadr;
627 
628         dev_dbg(doc->dev,
629               "docg4: %s: g4 page %08x\n", __func__, docg4_addr);
630 
631         sequence_reset(mtd);
632 
633         writew(DOCG4_SEQ_PAGE_READ, docptr + DOC_FLASHSEQUENCE);
634         writew(DOCG4_CMD_PAGE_READ, docptr + DOC_FLASHCOMMAND);
635         write_nop(docptr);
636 
637         write_addr(doc, docg4_addr);
638 
639         write_nop(docptr);
640         writew(DOCG4_CMD_READ2, docptr + DOC_FLASHCOMMAND);
641         write_nop(docptr);
642         write_nop(docptr);
643 
644         poll_status(doc);
645 }
646 
647 static void write_page_prologue(struct mtd_info *mtd, uint32_t docg4_addr)
648 {
649         /* first step in writing a page */
650 
651         struct nand_chip *nand = mtd_to_nand(mtd);
652         struct docg4_priv *doc = nand_get_controller_data(nand);
653         void __iomem *docptr = doc->virtadr;
654 
655         dev_dbg(doc->dev,
656               "docg4: %s: g4 addr: %x\n", __func__, docg4_addr);
657         sequence_reset(mtd);
658 
659         if (unlikely(reliable_mode)) {
660                 writew(DOCG4_SEQ_SETMODE, docptr + DOC_FLASHSEQUENCE);
661                 writew(DOCG4_CMD_FAST_MODE, docptr + DOC_FLASHCOMMAND);
662                 writew(DOC_CMD_RELIABLE_MODE, docptr + DOC_FLASHCOMMAND);
663                 write_nop(docptr);
664         }
665 
666         writew(DOCG4_SEQ_PAGEWRITE, docptr + DOC_FLASHSEQUENCE);
667         writew(DOCG4_CMD_PAGEWRITE, docptr + DOC_FLASHCOMMAND);
668         write_nop(docptr);
669         write_addr(doc, docg4_addr);
670         write_nop(docptr);
671         write_nop(docptr);
672         poll_status(doc);
673 }
674 
675 static uint32_t mtd_to_docg4_address(int page, int column)
676 {
677         /*
678          * Convert mtd address to format used by the device, 32 bit packed.
679          *
680          * Some notes on G4 addressing... The M-Sys documentation on this device
681          * claims that pages are 2K in length, and indeed, the format of the
682          * address used by the device reflects that.  But within each page are
683          * four 512 byte "sub-pages", each with its own oob data that is
684          * read/written immediately after the 512 bytes of page data.  This oob
685          * data contains the ecc bytes for the preceeding 512 bytes.
686          *
687          * Rather than tell the mtd nand infrastructure that page size is 2k,
688          * with four sub-pages each, we engage in a little subterfuge and tell
689          * the infrastructure code that pages are 512 bytes in size.  This is
690          * done because during the course of reverse-engineering the device, I
691          * never observed an instance where an entire 2K "page" was read or
692          * written as a unit.  Each "sub-page" is always addressed individually,
693          * its data read/written, and ecc handled before the next "sub-page" is
694          * addressed.
695          *
696          * This requires us to convert addresses passed by the mtd nand
697          * infrastructure code to those used by the device.
698          *
699          * The address that is written to the device consists of four bytes: the
700          * first two are the 2k page number, and the second is the index into
701          * the page.  The index is in terms of 16-bit half-words and includes
702          * the preceeding oob data, so e.g., the index into the second
703          * "sub-page" is 0x108, and the full device address of the start of mtd
704          * page 0x201 is 0x00800108.
705          */
706         int g4_page = page / 4;                       /* device's 2K page */
707         int g4_index = (page % 4) * 0x108 + column/2; /* offset into page */
708         return (g4_page << 16) | g4_index;            /* pack */
709 }
710 
711 static void docg4_command(struct mtd_info *mtd, unsigned command, int column,
712                           int page_addr)
713 {
714         /* handle standard nand commands */
715 
716         struct nand_chip *nand = mtd_to_nand(mtd);
717         struct docg4_priv *doc = nand_get_controller_data(nand);
718         uint32_t g4_addr = mtd_to_docg4_address(page_addr, column);
719 
720         dev_dbg(doc->dev, "%s %x, page_addr=%x, column=%x\n",
721               __func__, command, page_addr, column);
722 
723         /*
724          * Save the command and its arguments.  This enables emulation of
725          * standard flash devices, and also some optimizations.
726          */
727         doc->last_command.command = command;
728         doc->last_command.column = column;
729         doc->last_command.page = page_addr;
730 
731         switch (command) {
732 
733         case NAND_CMD_RESET:
734                 reset(mtd);
735                 break;
736 
737         case NAND_CMD_READ0:
738                 read_page_prologue(mtd, g4_addr);
739                 break;
740 
741         case NAND_CMD_STATUS:
742                 /* next call to read_byte() will expect a status */
743                 break;
744 
745         case NAND_CMD_SEQIN:
746                 if (unlikely(reliable_mode)) {
747                         uint16_t g4_page = g4_addr >> 16;
748 
749                         /* writes to odd-numbered 2k pages are invalid */
750                         if (g4_page & 0x01)
751                                 dev_warn(doc->dev,
752                                          "invalid reliable mode address\n");
753                 }
754 
755                 write_page_prologue(mtd, g4_addr);
756 
757                 /* hack for deferred write of oob bytes */
758                 if (doc->oob_page == page_addr)
759                         memcpy(nand->oob_poi, doc->oob_buf, 16);
760                 break;
761 
762         case NAND_CMD_PAGEPROG:
763                 pageprog(mtd);
764                 break;
765 
766         /* we don't expect these, based on review of nand_base.c */
767         case NAND_CMD_READOOB:
768         case NAND_CMD_READID:
769         case NAND_CMD_ERASE1:
770         case NAND_CMD_ERASE2:
771                 dev_warn(doc->dev, "docg4_command: "
772                          "unexpected nand command 0x%x\n", command);
773                 break;
774 
775         }
776 }
777 
778 static int read_page(struct mtd_info *mtd, struct nand_chip *nand,
779                      uint8_t *buf, int page, bool use_ecc)
780 {
781         struct docg4_priv *doc = nand_get_controller_data(nand);
782         void __iomem *docptr = doc->virtadr;
783         uint16_t status, edc_err, *buf16;
784         int bits_corrected = 0;
785 
786         dev_dbg(doc->dev, "%s: page %08x\n", __func__, page);
787 
788         writew(DOC_ECCCONF0_READ_MODE |
789                DOC_ECCCONF0_ECC_ENABLE |
790                DOC_ECCCONF0_UNKNOWN |
791                DOCG4_BCH_SIZE,
792                docptr + DOC_ECCCONF0);
793         write_nop(docptr);
794         write_nop(docptr);
795         write_nop(docptr);
796         write_nop(docptr);
797         write_nop(docptr);
798 
799         /* the 1st byte from the I/O reg is a status; the rest is page data */
800         status = readw(docptr + DOC_IOSPACE_DATA);
801         if (status & DOCG4_READ_ERROR) {
802                 dev_err(doc->dev,
803                         "docg4_read_page: bad status: 0x%02x\n", status);
804                 writew(0, docptr + DOC_DATAEND);
805                 return -EIO;
806         }
807 
808         dev_dbg(doc->dev, "%s: status = 0x%x\n", __func__, status);
809 
810         docg4_read_buf(mtd, buf, DOCG4_PAGE_SIZE); /* read the page data */
811 
812         /* this device always reads oob after page data */
813         /* first 14 oob bytes read from I/O reg */
814         docg4_read_buf(mtd, nand->oob_poi, 14);
815 
816         /* last 2 read from another reg */
817         buf16 = (uint16_t *)(nand->oob_poi + 14);
818         *buf16 = readw(docptr + DOCG4_MYSTERY_REG);
819 
820         write_nop(docptr);
821 
822         if (likely(use_ecc == true)) {
823 
824                 /* read the register that tells us if bitflip(s) detected  */
825                 edc_err = readw(docptr + DOC_ECCCONF1);
826                 edc_err = readw(docptr + DOC_ECCCONF1);
827                 dev_dbg(doc->dev, "%s: edc_err = 0x%02x\n", __func__, edc_err);
828 
829                 /* If bitflips are reported, attempt to correct with ecc */
830                 if (edc_err & DOC_ECCCONF1_BCH_SYNDROM_ERR) {
831                         bits_corrected = correct_data(mtd, buf, page);
832                         if (bits_corrected == -EBADMSG)
833                                 mtd->ecc_stats.failed++;
834                         else
835                                 mtd->ecc_stats.corrected += bits_corrected;
836                 }
837         }
838 
839         writew(0, docptr + DOC_DATAEND);
840         if (bits_corrected == -EBADMSG)   /* uncorrectable errors */
841                 return 0;
842         return bits_corrected;
843 }
844 
845 
846 static int docg4_read_page_raw(struct mtd_info *mtd, struct nand_chip *nand,
847                                uint8_t *buf, int oob_required, int page)
848 {
849         return read_page(mtd, nand, buf, page, false);
850 }
851 
852 static int docg4_read_page(struct mtd_info *mtd, struct nand_chip *nand,
853                            uint8_t *buf, int oob_required, int page)
854 {
855         return read_page(mtd, nand, buf, page, true);
856 }
857 
858 static int docg4_read_oob(struct mtd_info *mtd, struct nand_chip *nand,
859                           int page)
860 {
861         struct docg4_priv *doc = nand_get_controller_data(nand);
862         void __iomem *docptr = doc->virtadr;
863         uint16_t status;
864 
865         dev_dbg(doc->dev, "%s: page %x\n", __func__, page);
866 
867         docg4_command(mtd, NAND_CMD_READ0, nand->ecc.size, page);
868 
869         writew(DOC_ECCCONF0_READ_MODE | DOCG4_OOB_SIZE, docptr + DOC_ECCCONF0);
870         write_nop(docptr);
871         write_nop(docptr);
872         write_nop(docptr);
873         write_nop(docptr);
874         write_nop(docptr);
875 
876         /* the 1st byte from the I/O reg is a status; the rest is oob data */
877         status = readw(docptr + DOC_IOSPACE_DATA);
878         if (status & DOCG4_READ_ERROR) {
879                 dev_warn(doc->dev,
880                          "docg4_read_oob failed: status = 0x%02x\n", status);
881                 return -EIO;
882         }
883 
884         dev_dbg(doc->dev, "%s: status = 0x%x\n", __func__, status);
885 
886         docg4_read_buf(mtd, nand->oob_poi, 16);
887 
888         write_nop(docptr);
889         write_nop(docptr);
890         write_nop(docptr);
891         writew(0, docptr + DOC_DATAEND);
892         write_nop(docptr);
893 
894         return 0;
895 }
896 
897 static int docg4_erase_block(struct mtd_info *mtd, int page)
898 {
899         struct nand_chip *nand = mtd_to_nand(mtd);
900         struct docg4_priv *doc = nand_get_controller_data(nand);
901         void __iomem *docptr = doc->virtadr;
902         uint16_t g4_page;
903 
904         dev_dbg(doc->dev, "%s: page %04x\n", __func__, page);
905 
906         sequence_reset(mtd);
907 
908         writew(DOCG4_SEQ_BLOCKERASE, docptr + DOC_FLASHSEQUENCE);
909         writew(DOC_CMD_PROG_BLOCK_ADDR, docptr + DOC_FLASHCOMMAND);
910         write_nop(docptr);
911 
912         /* only 2 bytes of address are written to specify erase block */
913         g4_page = (uint16_t)(page / 4);  /* to g4's 2k page addressing */
914         writeb(g4_page & 0xff, docptr + DOC_FLASHADDRESS);
915         g4_page >>= 8;
916         writeb(g4_page & 0xff, docptr + DOC_FLASHADDRESS);
917         write_nop(docptr);
918 
919         /* start the erasure */
920         writew(DOC_CMD_ERASECYCLE2, docptr + DOC_FLASHCOMMAND);
921         write_nop(docptr);
922         write_nop(docptr);
923 
924         usleep_range(500, 1000); /* erasure is long; take a snooze */
925         poll_status(doc);
926         writew(DOCG4_SEQ_FLUSH, docptr + DOC_FLASHSEQUENCE);
927         writew(DOCG4_CMD_FLUSH, docptr + DOC_FLASHCOMMAND);
928         writew(DOC_ECCCONF0_READ_MODE | 4, docptr + DOC_ECCCONF0);
929         write_nop(docptr);
930         write_nop(docptr);
931         write_nop(docptr);
932         write_nop(docptr);
933         write_nop(docptr);
934 
935         read_progstatus(doc);
936 
937         writew(0, docptr + DOC_DATAEND);
938         write_nop(docptr);
939         poll_status(doc);
940         write_nop(docptr);
941 
942         return nand->waitfunc(mtd, nand);
943 }
944 
945 static int write_page(struct mtd_info *mtd, struct nand_chip *nand,
946                        const uint8_t *buf, bool use_ecc)
947 {
948         struct docg4_priv *doc = nand_get_controller_data(nand);
949         void __iomem *docptr = doc->virtadr;
950         uint8_t ecc_buf[8];
951 
952         dev_dbg(doc->dev, "%s...\n", __func__);
953 
954         writew(DOC_ECCCONF0_ECC_ENABLE |
955                DOC_ECCCONF0_UNKNOWN |
956                DOCG4_BCH_SIZE,
957                docptr + DOC_ECCCONF0);
958         write_nop(docptr);
959 
960         /* write the page data */
961         docg4_write_buf16(mtd, buf, DOCG4_PAGE_SIZE);
962 
963         /* oob bytes 0 through 5 are written to I/O reg */
964         docg4_write_buf16(mtd, nand->oob_poi, 6);
965 
966         /* oob byte 6 written to a separate reg */
967         writew(nand->oob_poi[6], docptr + DOCG4_OOB_6_7);
968 
969         write_nop(docptr);
970         write_nop(docptr);
971 
972         /* write hw-generated ecc bytes to oob */
973         if (likely(use_ecc == true)) {
974                 /* oob byte 7 is hamming code */
975                 uint8_t hamming = readb(docptr + DOC_HAMMINGPARITY);
976                 hamming = readb(docptr + DOC_HAMMINGPARITY); /* 2nd read */
977                 writew(hamming, docptr + DOCG4_OOB_6_7);
978                 write_nop(docptr);
979 
980                 /* read the 7 bch bytes from ecc regs */
981                 read_hw_ecc(docptr, ecc_buf);
982                 ecc_buf[7] = 0;         /* clear the "page written" flag */
983         }
984 
985         /* write user-supplied bytes to oob */
986         else {
987                 writew(nand->oob_poi[7], docptr + DOCG4_OOB_6_7);
988                 write_nop(docptr);
989                 memcpy(ecc_buf, &nand->oob_poi[8], 8);
990         }
991 
992         docg4_write_buf16(mtd, ecc_buf, 8);
993         write_nop(docptr);
994         write_nop(docptr);
995         writew(0, docptr + DOC_DATAEND);
996         write_nop(docptr);
997 
998         return 0;
999 }
1000 
1001 static int docg4_write_page_raw(struct mtd_info *mtd, struct nand_chip *nand,
1002                                 const uint8_t *buf, int oob_required, int page)
1003 {
1004         return write_page(mtd, nand, buf, false);
1005 }
1006 
1007 static int docg4_write_page(struct mtd_info *mtd, struct nand_chip *nand,
1008                              const uint8_t *buf, int oob_required, int page)
1009 {
1010         return write_page(mtd, nand, buf, true);
1011 }
1012 
1013 static int docg4_write_oob(struct mtd_info *mtd, struct nand_chip *nand,
1014                            int page)
1015 {
1016         /*
1017          * Writing oob-only is not really supported, because MLC nand must write
1018          * oob bytes at the same time as page data.  Nonetheless, we save the
1019          * oob buffer contents here, and then write it along with the page data
1020          * if the same page is subsequently written.  This allows user space
1021          * utilities that write the oob data prior to the page data to work
1022          * (e.g., nandwrite).  The disdvantage is that, if the intention was to
1023          * write oob only, the operation is quietly ignored.  Also, oob can get
1024          * corrupted if two concurrent processes are running nandwrite.
1025          */
1026 
1027         /* note that bytes 7..14 are hw generated hamming/ecc and overwritten */
1028         struct docg4_priv *doc = nand_get_controller_data(nand);
1029         doc->oob_page = page;
1030         memcpy(doc->oob_buf, nand->oob_poi, 16);
1031         return 0;
1032 }
1033 
1034 static int __init read_factory_bbt(struct mtd_info *mtd)
1035 {
1036         /*
1037          * The device contains a read-only factory bad block table.  Read it and
1038          * update the memory-based bbt accordingly.
1039          */
1040 
1041         struct nand_chip *nand = mtd_to_nand(mtd);
1042         struct docg4_priv *doc = nand_get_controller_data(nand);
1043         uint32_t g4_addr = mtd_to_docg4_address(DOCG4_FACTORY_BBT_PAGE, 0);
1044         uint8_t *buf;
1045         int i, block;
1046         __u32 eccfailed_stats = mtd->ecc_stats.failed;
1047 
1048         buf = kzalloc(DOCG4_PAGE_SIZE, GFP_KERNEL);
1049         if (buf == NULL)
1050                 return -ENOMEM;
1051 
1052         read_page_prologue(mtd, g4_addr);
1053         docg4_read_page(mtd, nand, buf, 0, DOCG4_FACTORY_BBT_PAGE);
1054 
1055         /*
1056          * If no memory-based bbt was created, exit.  This will happen if module
1057          * parameter ignore_badblocks is set.  Then why even call this function?
1058          * For an unknown reason, block erase always fails if it's the first
1059          * operation after device power-up.  The above read ensures it never is.
1060          * Ugly, I know.
1061          */
1062         if (nand->bbt == NULL)  /* no memory-based bbt */
1063                 goto exit;
1064 
1065         if (mtd->ecc_stats.failed > eccfailed_stats) {
1066                 /*
1067                  * Whoops, an ecc failure ocurred reading the factory bbt.
1068                  * It is stored redundantly, so we get another chance.
1069                  */
1070                 eccfailed_stats = mtd->ecc_stats.failed;
1071                 docg4_read_page(mtd, nand, buf, 0, DOCG4_REDUNDANT_BBT_PAGE);
1072                 if (mtd->ecc_stats.failed > eccfailed_stats) {
1073                         dev_warn(doc->dev,
1074                                  "The factory bbt could not be read!\n");
1075                         goto exit;
1076                 }
1077         }
1078 
1079         /*
1080          * Parse factory bbt and update memory-based bbt.  Factory bbt format is
1081          * simple: one bit per block, block numbers increase left to right (msb
1082          * to lsb).  Bit clear means bad block.
1083          */
1084         for (i = block = 0; block < DOCG4_NUMBLOCKS; block += 8, i++) {
1085                 int bitnum;
1086                 unsigned long bits = ~buf[i];
1087                 for_each_set_bit(bitnum, &bits, 8) {
1088                         int badblock = block + 7 - bitnum;
1089                         nand->bbt[badblock / 4] |=
1090                                 0x03 << ((badblock % 4) * 2);
1091                         mtd->ecc_stats.badblocks++;
1092                         dev_notice(doc->dev, "factory-marked bad block: %d\n",
1093                                    badblock);
1094                 }
1095         }
1096  exit:
1097         kfree(buf);
1098         return 0;
1099 }
1100 
1101 static int docg4_block_markbad(struct mtd_info *mtd, loff_t ofs)
1102 {
1103         /*
1104          * Mark a block as bad.  Bad blocks are marked in the oob area of the
1105          * first page of the block.  The default scan_bbt() in the nand
1106          * infrastructure code works fine for building the memory-based bbt
1107          * during initialization, as does the nand infrastructure function that
1108          * checks if a block is bad by reading the bbt.  This function replaces
1109          * the nand default because writes to oob-only are not supported.
1110          */
1111 
1112         int ret, i;
1113         uint8_t *buf;
1114         struct nand_chip *nand = mtd_to_nand(mtd);
1115         struct docg4_priv *doc = nand_get_controller_data(nand);
1116         struct nand_bbt_descr *bbtd = nand->badblock_pattern;
1117         int page = (int)(ofs >> nand->page_shift);
1118         uint32_t g4_addr = mtd_to_docg4_address(page, 0);
1119 
1120         dev_dbg(doc->dev, "%s: %08llx\n", __func__, ofs);
1121 
1122         if (unlikely(ofs & (DOCG4_BLOCK_SIZE - 1)))
1123                 dev_warn(doc->dev, "%s: ofs %llx not start of block!\n",
1124                          __func__, ofs);
1125 
1126         /* allocate blank buffer for page data */
1127         buf = kzalloc(DOCG4_PAGE_SIZE, GFP_KERNEL);
1128         if (buf == NULL)
1129                 return -ENOMEM;
1130 
1131         /* write bit-wise negation of pattern to oob buffer */
1132         memset(nand->oob_poi, 0xff, mtd->oobsize);
1133         for (i = 0; i < bbtd->len; i++)
1134                 nand->oob_poi[bbtd->offs + i] = ~bbtd->pattern[i];
1135 
1136         /* write first page of block */
1137         write_page_prologue(mtd, g4_addr);
1138         docg4_write_page(mtd, nand, buf, 1, page);
1139         ret = pageprog(mtd);
1140 
1141         kfree(buf);
1142 
1143         return ret;
1144 }
1145 
1146 static int docg4_block_neverbad(struct mtd_info *mtd, loff_t ofs)
1147 {
1148         /* only called when module_param ignore_badblocks is set */
1149         return 0;
1150 }
1151 
1152 static int docg4_suspend(struct platform_device *pdev, pm_message_t state)
1153 {
1154         /*
1155          * Put the device into "deep power-down" mode.  Note that CE# must be
1156          * deasserted for this to take effect.  The xscale, e.g., can be
1157          * configured to float this signal when the processor enters power-down,
1158          * and a suitable pull-up ensures its deassertion.
1159          */
1160 
1161         int i;
1162         uint8_t pwr_down;
1163         struct docg4_priv *doc = platform_get_drvdata(pdev);
1164         void __iomem *docptr = doc->virtadr;
1165 
1166         dev_dbg(doc->dev, "%s...\n", __func__);
1167 
1168         /* poll the register that tells us we're ready to go to sleep */
1169         for (i = 0; i < 10; i++) {
1170                 pwr_down = readb(docptr + DOC_POWERMODE);
1171                 if (pwr_down & DOC_POWERDOWN_READY)
1172                         break;
1173                 usleep_range(1000, 4000);
1174         }
1175 
1176         if (pwr_down & DOC_POWERDOWN_READY) {
1177                 dev_err(doc->dev, "suspend failed; "
1178                         "timeout polling DOC_POWERDOWN_READY\n");
1179                 return -EIO;
1180         }
1181 
1182         writew(DOC_ASICMODE_POWERDOWN | DOC_ASICMODE_MDWREN,
1183                docptr + DOC_ASICMODE);
1184         writew(~(DOC_ASICMODE_POWERDOWN | DOC_ASICMODE_MDWREN),
1185                docptr + DOC_ASICMODECONFIRM);
1186 
1187         write_nop(docptr);
1188 
1189         return 0;
1190 }
1191 
1192 static int docg4_resume(struct platform_device *pdev)
1193 {
1194 
1195         /*
1196          * Exit power-down.  Twelve consecutive reads of the address below
1197          * accomplishes this, assuming CE# has been asserted.
1198          */
1199 
1200         struct docg4_priv *doc = platform_get_drvdata(pdev);
1201         void __iomem *docptr = doc->virtadr;
1202         int i;
1203 
1204         dev_dbg(doc->dev, "%s...\n", __func__);
1205 
1206         for (i = 0; i < 12; i++)
1207                 readb(docptr + 0x1fff);
1208 
1209         return 0;
1210 }
1211 
1212 static void __init init_mtd_structs(struct mtd_info *mtd)
1213 {
1214         /* initialize mtd and nand data structures */
1215 
1216         /*
1217          * Note that some of the following initializations are not usually
1218          * required within a nand driver because they are performed by the nand
1219          * infrastructure code as part of nand_scan().  In this case they need
1220          * to be initialized here because we skip call to nand_scan_ident() (the
1221          * first half of nand_scan()).  The call to nand_scan_ident() is skipped
1222          * because for this device the chip id is not read in the manner of a
1223          * standard nand device.  Unfortunately, nand_scan_ident() does other
1224          * things as well, such as call nand_set_defaults().
1225          */
1226 
1227         struct nand_chip *nand = mtd_to_nand(mtd);
1228         struct docg4_priv *doc = nand_get_controller_data(nand);
1229 
1230         mtd->size = DOCG4_CHIP_SIZE;
1231         mtd->name = "Msys_Diskonchip_G4";
1232         mtd->writesize = DOCG4_PAGE_SIZE;
1233         mtd->erasesize = DOCG4_BLOCK_SIZE;
1234         mtd->oobsize = DOCG4_OOB_SIZE;
1235         mtd_set_ooblayout(mtd, &docg4_ooblayout_ops);
1236         nand->chipsize = DOCG4_CHIP_SIZE;
1237         nand->chip_shift = DOCG4_CHIP_SHIFT;
1238         nand->bbt_erase_shift = nand->phys_erase_shift = DOCG4_ERASE_SHIFT;
1239         nand->chip_delay = 20;
1240         nand->page_shift = DOCG4_PAGE_SHIFT;
1241         nand->pagemask = 0x3ffff;
1242         nand->badblockpos = NAND_LARGE_BADBLOCK_POS;
1243         nand->badblockbits = 8;
1244         nand->ecc.mode = NAND_ECC_HW_SYNDROME;
1245         nand->ecc.size = DOCG4_PAGE_SIZE;
1246         nand->ecc.prepad = 8;
1247         nand->ecc.bytes = 8;
1248         nand->ecc.strength = DOCG4_T;
1249         nand->options = NAND_BUSWIDTH_16 | NAND_NO_SUBPAGE_WRITE;
1250         nand->IO_ADDR_R = nand->IO_ADDR_W = doc->virtadr + DOC_IOSPACE_DATA;
1251         nand->controller = &nand->hwcontrol;
1252         spin_lock_init(&nand->controller->lock);
1253         init_waitqueue_head(&nand->controller->wq);
1254 
1255         /* methods */
1256         nand->cmdfunc = docg4_command;
1257         nand->waitfunc = docg4_wait;
1258         nand->select_chip = docg4_select_chip;
1259         nand->read_byte = docg4_read_byte;
1260         nand->block_markbad = docg4_block_markbad;
1261         nand->read_buf = docg4_read_buf;
1262         nand->write_buf = docg4_write_buf16;
1263         nand->erase = docg4_erase_block;
1264         nand->ecc.read_page = docg4_read_page;
1265         nand->ecc.write_page = docg4_write_page;
1266         nand->ecc.read_page_raw = docg4_read_page_raw;
1267         nand->ecc.write_page_raw = docg4_write_page_raw;
1268         nand->ecc.read_oob = docg4_read_oob;
1269         nand->ecc.write_oob = docg4_write_oob;
1270 
1271         /*
1272          * The way the nand infrastructure code is written, a memory-based bbt
1273          * is not created if NAND_SKIP_BBTSCAN is set.  With no memory bbt,
1274          * nand->block_bad() is used.  So when ignoring bad blocks, we skip the
1275          * scan and define a dummy block_bad() which always returns 0.
1276          */
1277         if (ignore_badblocks) {
1278                 nand->options |= NAND_SKIP_BBTSCAN;
1279                 nand->block_bad = docg4_block_neverbad;
1280         }
1281 
1282 }
1283 
1284 static int __init read_id_reg(struct mtd_info *mtd)
1285 {
1286         struct nand_chip *nand = mtd_to_nand(mtd);
1287         struct docg4_priv *doc = nand_get_controller_data(nand);
1288         void __iomem *docptr = doc->virtadr;
1289         uint16_t id1, id2;
1290 
1291         /* check for presence of g4 chip by reading id registers */
1292         id1 = readw(docptr + DOC_CHIPID);
1293         id1 = readw(docptr + DOCG4_MYSTERY_REG);
1294         id2 = readw(docptr + DOC_CHIPID_INV);
1295         id2 = readw(docptr + DOCG4_MYSTERY_REG);
1296 
1297         if (id1 == DOCG4_IDREG1_VALUE && id2 == DOCG4_IDREG2_VALUE) {
1298                 dev_info(doc->dev,
1299                          "NAND device: 128MiB Diskonchip G4 detected\n");
1300                 return 0;
1301         }
1302 
1303         return -ENODEV;
1304 }
1305 
1306 static char const *part_probes[] = { "cmdlinepart", "saftlpart", NULL };
1307 
1308 static int __init probe_docg4(struct platform_device *pdev)
1309 {
1310         struct mtd_info *mtd;
1311         struct nand_chip *nand;
1312         void __iomem *virtadr;
1313         struct docg4_priv *doc;
1314         int len, retval;
1315         struct resource *r;
1316         struct device *dev = &pdev->dev;
1317 
1318         r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
1319         if (r == NULL) {
1320                 dev_err(dev, "no io memory resource defined!\n");
1321                 return -ENODEV;
1322         }
1323 
1324         virtadr = ioremap(r->start, resource_size(r));
1325         if (!virtadr) {
1326                 dev_err(dev, "Diskonchip ioremap failed: %pR\n", r);
1327                 return -EIO;
1328         }
1329 
1330         len = sizeof(struct nand_chip) + sizeof(struct docg4_priv);
1331         nand = kzalloc(len, GFP_KERNEL);
1332         if (nand == NULL) {
1333                 retval = -ENOMEM;
1334                 goto fail_unmap;
1335         }
1336 
1337         mtd = nand_to_mtd(nand);
1338         doc = (struct docg4_priv *) (nand + 1);
1339         nand_set_controller_data(nand, doc);
1340         mtd->dev.parent = &pdev->dev;
1341         doc->virtadr = virtadr;
1342         doc->dev = dev;
1343 
1344         init_mtd_structs(mtd);
1345 
1346         /* initialize kernel bch algorithm */
1347         doc->bch = init_bch(DOCG4_M, DOCG4_T, DOCG4_PRIMITIVE_POLY);
1348         if (doc->bch == NULL) {
1349                 retval = -EINVAL;
1350                 goto fail;
1351         }
1352 
1353         platform_set_drvdata(pdev, doc);
1354 
1355         reset(mtd);
1356         retval = read_id_reg(mtd);
1357         if (retval == -ENODEV) {
1358                 dev_warn(dev, "No diskonchip G4 device found.\n");
1359                 goto fail;
1360         }
1361 
1362         retval = nand_scan_tail(mtd);
1363         if (retval)
1364                 goto fail;
1365 
1366         retval = read_factory_bbt(mtd);
1367         if (retval)
1368                 goto fail;
1369 
1370         retval = mtd_device_parse_register(mtd, part_probes, NULL, NULL, 0);
1371         if (retval)
1372                 goto fail;
1373 
1374         doc->mtd = mtd;
1375         return 0;
1376 
1377 fail:
1378         nand_release(mtd); /* deletes partitions and mtd devices */
1379         free_bch(doc->bch);
1380         kfree(nand);
1381 
1382 fail_unmap:
1383         iounmap(virtadr);
1384 
1385         return retval;
1386 }
1387 
1388 static int __exit cleanup_docg4(struct platform_device *pdev)
1389 {
1390         struct docg4_priv *doc = platform_get_drvdata(pdev);
1391         nand_release(doc->mtd);
1392         free_bch(doc->bch);
1393         kfree(mtd_to_nand(doc->mtd));
1394         iounmap(doc->virtadr);
1395         return 0;
1396 }
1397 
1398 static struct platform_driver docg4_driver = {
1399         .driver         = {
1400                 .name   = "docg4",
1401         },
1402         .suspend        = docg4_suspend,
1403         .resume         = docg4_resume,
1404         .remove         = __exit_p(cleanup_docg4),
1405 };
1406 
1407 module_platform_driver_probe(docg4_driver, probe_docg4);
1408 
1409 MODULE_LICENSE("GPL");
1410 MODULE_AUTHOR("Mike Dunn");
1411 MODULE_DESCRIPTION("M-Systems DiskOnChip G4 device driver");
1412 

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