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   1 /*
   2  * NAND flash simulator.
   3  *
   4  * Author: Artem B. Bityuckiy <dedekind@oktetlabs.ru>, <dedekind@infradead.org>
   5  *
   6  * Copyright (C) 2004 Nokia Corporation
   7  *
   8  * Note: NS means "NAND Simulator".
   9  * Note: Input means input TO flash chip, output means output FROM chip.
  10  *
  11  * This program is free software; you can redistribute it and/or modify it
  12  * under the terms of the GNU General Public License as published by the
  13  * Free Software Foundation; either version 2, or (at your option) any later
  14  * version.
  15  *
  16  * This program is distributed in the hope that it will be useful, but
  17  * WITHOUT ANY WARRANTY; without even the implied warranty of
  18  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General
  19  * Public License for more details.
  20  *
  21  * You should have received a copy of the GNU General Public License
  22  * along with this program; if not, write to the Free Software
  23  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307, USA
  24  *
  25  * $Id: nandsim.c,v 1.8 2005/03/19 15:33:56 dedekind Exp $
  26  */
  27
  28 #include <linux/init.h>
  29 #include <linux/types.h>
  30 #include <linux/module.h>
  31 #include <linux/moduleparam.h>
  32 #include <linux/vmalloc.h>
  33 #include <linux/slab.h>
  34 #include <linux/errno.h>
  35 #include <linux/string.h>
  36 #include <linux/mtd/mtd.h>
  37 #include <linux/mtd/nand.h>
  38 #include <linux/mtd/partitions.h>
  39 #include <linux/delay.h>
  40
  41 /* Default simulator parameters values */
  42 #if !defined(CONFIG_NANDSIM_FIRST_ID_BYTE)  || \
  43     !defined(CONFIG_NANDSIM_SECOND_ID_BYTE) || \
  44     !defined(CONFIG_NANDSIM_THIRD_ID_BYTE)  || \
  45     !defined(CONFIG_NANDSIM_FOURTH_ID_BYTE)
  46 #define CONFIG_NANDSIM_FIRST_ID_BYTE  0x98
  47 #define CONFIG_NANDSIM_SECOND_ID_BYTE 0x39
  48 #define CONFIG_NANDSIM_THIRD_ID_BYTE  0xFF /* No byte */
  49 #define CONFIG_NANDSIM_FOURTH_ID_BYTE 0xFF /* No byte */
  50 #endif
  51
  52 #ifndef CONFIG_NANDSIM_ACCESS_DELAY
  53 #define CONFIG_NANDSIM_ACCESS_DELAY 25
  54 #endif
  55 #ifndef CONFIG_NANDSIM_PROGRAMM_DELAY
  56 #define CONFIG_NANDSIM_PROGRAMM_DELAY 200
  57 #endif
  58 #ifndef CONFIG_NANDSIM_ERASE_DELAY
  59 #define CONFIG_NANDSIM_ERASE_DELAY 2
  60 #endif
  61 #ifndef CONFIG_NANDSIM_OUTPUT_CYCLE
  62 #define CONFIG_NANDSIM_OUTPUT_CYCLE 40
  63 #endif
  64 #ifndef CONFIG_NANDSIM_INPUT_CYCLE
  65 #define CONFIG_NANDSIM_INPUT_CYCLE  50
  66 #endif
  67 #ifndef CONFIG_NANDSIM_BUS_WIDTH
  68 #define CONFIG_NANDSIM_BUS_WIDTH  8
  69 #endif
  70 #ifndef CONFIG_NANDSIM_DO_DELAYS
  71 #define CONFIG_NANDSIM_DO_DELAYS  0
  72 #endif
  73 #ifndef CONFIG_NANDSIM_LOG
  74 #define CONFIG_NANDSIM_LOG        0
  75 #endif
  76 #ifndef CONFIG_NANDSIM_DBG
  77 #define CONFIG_NANDSIM_DBG        0
  78 #endif
  79
  80 static uint first_id_byte  = CONFIG_NANDSIM_FIRST_ID_BYTE;
  81 static uint second_id_byte = CONFIG_NANDSIM_SECOND_ID_BYTE;
  82 static uint third_id_byte  = CONFIG_NANDSIM_THIRD_ID_BYTE;
  83 static uint fourth_id_byte = CONFIG_NANDSIM_FOURTH_ID_BYTE;
  84 static uint access_delay   = CONFIG_NANDSIM_ACCESS_DELAY;
  85 static uint programm_delay = CONFIG_NANDSIM_PROGRAMM_DELAY;
  86 static uint erase_delay    = CONFIG_NANDSIM_ERASE_DELAY;
  87 static uint output_cycle   = CONFIG_NANDSIM_OUTPUT_CYCLE;
  88 static uint input_cycle    = CONFIG_NANDSIM_INPUT_CYCLE;
  89 static uint bus_width      = CONFIG_NANDSIM_BUS_WIDTH;
  90 static uint do_delays      = CONFIG_NANDSIM_DO_DELAYS;
  91 static uint log            = CONFIG_NANDSIM_LOG;
  92 static uint dbg            = CONFIG_NANDSIM_DBG;
  93
  94 module_param(first_id_byte,  uint, 0400);
  95 module_param(second_id_byte, uint, 0400);
  96 module_param(third_id_byte,  uint, 0400);
  97 module_param(fourth_id_byte, uint, 0400);
  98 module_param(access_delay,   uint, 0400);
  99 module_param(programm_delay, uint, 0400);
 100 module_param(erase_delay,    uint, 0400);
 101 module_param(output_cycle,   uint, 0400);
 102 module_param(input_cycle,    uint, 0400);
 103 module_param(bus_width,      uint, 0400);
 104 module_param(do_delays,      uint, 0400);
 105 module_param(log,            uint, 0400);
 106 module_param(dbg,            uint, 0400);
 107
 108 MODULE_PARM_DESC(first_id_byte,  "The fist byte returned by NAND Flash 'read ID' command (manufaturer ID)");
 109 MODULE_PARM_DESC(second_id_byte, "The second byte returned by NAND Flash 'read ID' command (chip ID)");
 110 MODULE_PARM_DESC(third_id_byte,  "The third byte returned by NAND Flash 'read ID' command");
 111 MODULE_PARM_DESC(fourth_id_byte, "The fourth byte returned by NAND Flash 'read ID' command");
 112 MODULE_PARM_DESC(access_delay,   "Initial page access delay (microiseconds)");
 113 MODULE_PARM_DESC(programm_delay, "Page programm delay (microseconds");
 114 MODULE_PARM_DESC(erase_delay,    "Sector erase delay (milliseconds)");
 115 MODULE_PARM_DESC(output_cycle,   "Word output (from flash) time (nanodeconds)");
 116 MODULE_PARM_DESC(input_cycle,    "Word input (to flash) time (nanodeconds)");
 117 MODULE_PARM_DESC(bus_width,      "Chip's bus width (8- or 16-bit)");
 118 MODULE_PARM_DESC(do_delays,      "Simulate NAND delays using busy-waits if not zero");
 119 MODULE_PARM_DESC(log,            "Perform logging if not zero");
 120 MODULE_PARM_DESC(dbg,            "Output debug information if not zero");
 121
 122 /* The largest possible page size */
 123 #define NS_LARGEST_PAGE_SIZE    2048
 124
 125 /* The prefix for simulator output */
 126 #define NS_OUTPUT_PREFIX "[nandsim]"
 127
 128 /* Simulator's output macros (logging, debugging, warning, error) */
 129 #define NS_LOG(args...) \
 130         do { if (log) printk(KERN_DEBUG NS_OUTPUT_PREFIX " log: " args); } while(0)
 131 #define NS_DBG(args...) \
 132         do { if (dbg) printk(KERN_DEBUG NS_OUTPUT_PREFIX " debug: " args); } while(0)
 133 #define NS_WARN(args...) \
 134         do { printk(KERN_WARNING NS_OUTPUT_PREFIX " warnig: " args); } while(0)
 135 #define NS_ERR(args...) \
 136         do { printk(KERN_ERR NS_OUTPUT_PREFIX " errorr: " args); } while(0)
 137
 138 /* Busy-wait delay macros (microseconds, milliseconds) */
 139 #define NS_UDELAY(us) \
 140         do { if (do_delays) udelay(us); } while(0)
 141 #define NS_MDELAY(us) \
 142         do { if (do_delays) mdelay(us); } while(0)
 143
 144 /* Is the nandsim structure initialized ? */
 145 #define NS_IS_INITIALIZED(ns) ((ns)->geom.totsz != 0)
 146
 147 /* Good operation completion status */
 148 #define NS_STATUS_OK(ns) (NAND_STATUS_READY | (NAND_STATUS_WP * ((ns)->lines.wp == 0)))
 149
 150 /* Operation failed completion status */
 151 #define NS_STATUS_FAILED(ns) (NAND_STATUS_FAIL | NS_STATUS_OK(ns))
 152
 153 /* Calculate the page offset in flash RAM image by (row, column) address */
 154 #define NS_RAW_OFFSET(ns) \
 155         (((ns)->regs.row << (ns)->geom.pgshift) + ((ns)->regs.row * (ns)->geom.oobsz) + (ns)->regs.column)
 156
 157 /* Calculate the OOB offset in flash RAM image by (row, column) address */
 158 #define NS_RAW_OFFSET_OOB(ns) (NS_RAW_OFFSET(ns) + ns->geom.pgsz)
 159
 160 /* After a command is input, the simulator goes to one of the following states */
 161 #define STATE_CMD_READ0        0x00000001 /* read data from the beginning of page */
 162 #define STATE_CMD_READ1        0x00000002 /* read data from the second half of page */
 163 #define STATE_CMD_READSTART      0x00000003 /* read data second command (large page devices) */
 164 #define STATE_CMD_PAGEPROG     0x00000004 /* start page programm */
 165 #define STATE_CMD_READOOB      0x00000005 /* read OOB area */
 166 #define STATE_CMD_ERASE1       0x00000006 /* sector erase first command */
 167 #define STATE_CMD_STATUS       0x00000007 /* read status */
 168 #define STATE_CMD_STATUS_M     0x00000008 /* read multi-plane status (isn't implemented) */
 169 #define STATE_CMD_SEQIN        0x00000009 /* sequential data imput */
 170 #define STATE_CMD_READID       0x0000000A /* read ID */
 171 #define STATE_CMD_ERASE2       0x0000000B /* sector erase second command */
 172 #define STATE_CMD_RESET        0x0000000C /* reset */
 173 #define STATE_CMD_MASK         0x0000000F /* command states mask */
 174
 175 /* After an addres is input, the simulator goes to one of these states */
 176 #define STATE_ADDR_PAGE        0x00000010 /* full (row, column) address is accepted */
 177 #define STATE_ADDR_SEC         0x00000020 /* sector address was accepted */
 178 #define STATE_ADDR_ZERO        0x00000030 /* one byte zero address was accepted */
 179 #define STATE_ADDR_MASK        0x00000030 /* address states mask */
 180
 181 /* Durind data input/output the simulator is in these states */
 182 #define STATE_DATAIN           0x00000100 /* waiting for data input */
 183 #define STATE_DATAIN_MASK      0x00000100 /* data input states mask */
 184
 185 #define STATE_DATAOUT          0x00001000 /* waiting for page data output */
 186 #define STATE_DATAOUT_ID       0x00002000 /* waiting for ID bytes output */
 187 #define STATE_DATAOUT_STATUS   0x00003000 /* waiting for status output */
 188 #define STATE_DATAOUT_STATUS_M 0x00004000 /* waiting for multi-plane status output */
 189 #define STATE_DATAOUT_MASK     0x00007000 /* data output states mask */
 190
 191 /* Previous operation is done, ready to accept new requests */
 192 #define STATE_READY            0x00000000
 193
 194 /* This state is used to mark that the next state isn't known yet */
 195 #define STATE_UNKNOWN          0x10000000
 196
 197 /* Simulator's actions bit masks */
 198 #define ACTION_CPY       0x00100000 /* copy page/OOB to the internal buffer */
 199 #define ACTION_PRGPAGE   0x00200000 /* programm the internal buffer to flash */
 200 #define ACTION_SECERASE  0x00300000 /* erase sector */
 201 #define ACTION_ZEROOFF   0x00400000 /* don't add any offset to address */
 202 #define ACTION_HALFOFF   0x00500000 /* add to address half of page */
 203 #define ACTION_OOBOFF    0x00600000 /* add to address OOB offset */
 204 #define ACTION_MASK      0x00700000 /* action mask */
 205
 206 #define NS_OPER_NUM      12 /* Number of operations supported by the simulator */
 207 #define NS_OPER_STATES   6  /* Maximum number of states in operation */
 208
 209 #define OPT_ANY          0xFFFFFFFF /* any chip supports this operation */
 210 #define OPT_PAGE256      0x00000001 /* 256-byte  page chips */
 211 #define OPT_PAGE512      0x00000002 /* 512-byte  page chips */
 212 #define OPT_PAGE2048     0x00000008 /* 2048-byte page chips */
 213 #define OPT_SMARTMEDIA   0x00000010 /* SmartMedia technology chips */
 214 #define OPT_AUTOINCR     0x00000020 /* page number auto inctimentation is possible */
 215 #define OPT_PAGE512_8BIT 0x00000040 /* 512-byte page chips with 8-bit bus width */
 216 #define OPT_LARGEPAGE    (OPT_PAGE2048) /* 2048-byte page chips */
 217 #define OPT_SMALLPAGE    (OPT_PAGE256  | OPT_PAGE512)  /* 256 and 512-byte page chips */
 218
 219 /* Remove action bits ftom state */
 220 #define NS_STATE(x) ((x) & ~ACTION_MASK)
 221
 222 /*
 223  * Maximum previous states which need to be saved. Currently saving is
 224  * only needed for page programm operation with preceeded read command
 225  * (which is only valid for 512-byte pages).
 226  */
 227 #define NS_MAX_PREVSTATES 1
 228
 229 /*
 230  * A union to represent flash memory contents and flash buffer.
 231  */
 232 union ns_mem {
 233         u_char *byte;    /* for byte access */
 234         uint16_t *word;  /* for 16-bit word access */
 235 };
 236
 237 /*
 238  * The structure which describes all the internal simulator data.
 239  */
 240 struct nandsim {
 241         struct mtd_partition part;
 242
 243         uint busw;              /* flash chip bus width (8 or 16) */
 244         u_char ids[4];          /* chip's ID bytes */
 245         uint32_t options;       /* chip's characteristic bits */
 246         uint32_t state;         /* current chip state */
 247         uint32_t nxstate;       /* next expected state */
 248
 249         uint32_t *op;           /* current operation, NULL operations isn't known yet  */
 250         uint32_t pstates[NS_MAX_PREVSTATES]; /* previous states */
 251         uint16_t npstates;      /* number of previous states saved */
 252         uint16_t stateidx;      /* current state index */
 253
 254         /* The simulated NAND flash pages array */
 255         union ns_mem *pages;
 256
 257         /* Internal buffer of page + OOB size bytes */
 258         union ns_mem buf;
 259
 260         /* NAND flash "geometry" */
 261         struct nandsin_geometry {
 262                 uint32_t totsz;     /* total flash size, bytes */
 263                 uint32_t secsz;     /* flash sector (erase block) size, bytes */
 264                 uint pgsz;          /* NAND flash page size, bytes */
 265                 uint oobsz;         /* page OOB area size, bytes */
 266                 uint32_t totszoob;  /* total flash size including OOB, bytes */
 267                 uint pgszoob;       /* page size including OOB , bytes*/
 268                 uint secszoob;      /* sector size including OOB, bytes */
 269                 uint pgnum;         /* total number of pages */
 270                 uint pgsec;         /* number of pages per sector */
 271                 uint secshift;      /* bits number in sector size */
 272                 uint pgshift;       /* bits number in page size */
 273                 uint oobshift;      /* bits number in OOB size */
 274                 uint pgaddrbytes;   /* bytes per page address */
 275                 uint secaddrbytes;  /* bytes per sector address */
 276                 uint idbytes;       /* the number ID bytes that this chip outputs */
 277         } geom;
 278
 279         /* NAND flash internal registers */
 280         struct nandsim_regs {
 281                 unsigned command; /* the command register */
 282                 u_char   status;  /* the status register */
 283                 uint     row;     /* the page number */
 284                 uint     column;  /* the offset within page */
 285                 uint     count;   /* internal counter */
 286                 uint     num;     /* number of bytes which must be processed */
 287                 uint     off;     /* fixed page offset */
 288         } regs;
 289
 290         /* NAND flash lines state */
 291         struct ns_lines_status {
 292                 int ce;  /* chip Enable */
 293                 int cle; /* command Latch Enable */
 294                 int ale; /* address Latch Enable */
 295                 int wp;  /* write Protect */
 296         } lines;
 297 };
 298
 299 /*
 300  * Operations array. To perform any operation the simulator must pass
 301  * through the correspondent states chain.
 302  */
 303 static struct nandsim_operations {
 304         uint32_t reqopts;  /* options which are required to perform the operation */
 305         uint32_t states[NS_OPER_STATES]; /* operation's states */
 306 } ops[NS_OPER_NUM] = {
 307         /* Read page + OOB from the beginning */
 308         {OPT_SMALLPAGE, {STATE_CMD_READ0 | ACTION_ZEROOFF, STATE_ADDR_PAGE | ACTION_CPY,
 309                         STATE_DATAOUT, STATE_READY}},
 310         /* Read page + OOB from the second half */
 311         {OPT_PAGE512_8BIT, {STATE_CMD_READ1 | ACTION_HALFOFF, STATE_ADDR_PAGE | ACTION_CPY,
 312                         STATE_DATAOUT, STATE_READY}},
 313         /* Read OOB */
 314         {OPT_SMALLPAGE, {STATE_CMD_READOOB | ACTION_OOBOFF, STATE_ADDR_PAGE | ACTION_CPY,
 315                         STATE_DATAOUT, STATE_READY}},
 316         /* Programm page starting from the beginning */
 317         {OPT_ANY, {STATE_CMD_SEQIN, STATE_ADDR_PAGE, STATE_DATAIN,
 318                         STATE_CMD_PAGEPROG | ACTION_PRGPAGE, STATE_READY}},
 319         /* Programm page starting from the beginning */
 320         {OPT_SMALLPAGE, {STATE_CMD_READ0, STATE_CMD_SEQIN | ACTION_ZEROOFF, STATE_ADDR_PAGE,
 321                               STATE_DATAIN, STATE_CMD_PAGEPROG | ACTION_PRGPAGE, STATE_READY}},
 322         /* Programm page starting from the second half */
 323         {OPT_PAGE512, {STATE_CMD_READ1, STATE_CMD_SEQIN | ACTION_HALFOFF, STATE_ADDR_PAGE,
 324                               STATE_DATAIN, STATE_CMD_PAGEPROG | ACTION_PRGPAGE, STATE_READY}},
 325         /* Programm OOB */
 326         {OPT_SMALLPAGE, {STATE_CMD_READOOB, STATE_CMD_SEQIN | ACTION_OOBOFF, STATE_ADDR_PAGE,
 327                               STATE_DATAIN, STATE_CMD_PAGEPROG | ACTION_PRGPAGE, STATE_READY}},
 328         /* Erase sector */
 329         {OPT_ANY, {STATE_CMD_ERASE1, STATE_ADDR_SEC, STATE_CMD_ERASE2 | ACTION_SECERASE, STATE_READY}},
 330         /* Read status */
 331         {OPT_ANY, {STATE_CMD_STATUS, STATE_DATAOUT_STATUS, STATE_READY}},
 332         /* Read multi-plane status */
 333         {OPT_SMARTMEDIA, {STATE_CMD_STATUS_M, STATE_DATAOUT_STATUS_M, STATE_READY}},
 334         /* Read ID */
 335         {OPT_ANY, {STATE_CMD_READID, STATE_ADDR_ZERO, STATE_DATAOUT_ID, STATE_READY}},
 336         /* Large page devices read page */
 337         {OPT_LARGEPAGE, {STATE_CMD_READ0, STATE_ADDR_PAGE, STATE_CMD_READSTART | ACTION_CPY,
 338                                STATE_DATAOUT, STATE_READY}}
 339 };
 340
 341 /* MTD structure for NAND controller */
 342 static struct mtd_info *nsmtd;
 343
 344 static u_char ns_verify_buf[NS_LARGEST_PAGE_SIZE];
 345
 346 /*
 347  * Allocate array of page pointers and initialize the array to NULL
 348  * pointers.
 349  *
 350  * RETURNS: 0 if success, -ENOMEM if memory alloc fails.
 351  */
 352 static int alloc_device(struct nandsim *ns)
 353 {
 354         int i;
 355
 356         ns->pages = vmalloc(ns->geom.pgnum * sizeof(union ns_mem));
 357         if (!ns->pages) {
 358                 NS_ERR("alloc_map: unable to allocate page array\n");
 359                 return -ENOMEM;
 360         }
 361         for (i = 0; i < ns->geom.pgnum; i++) {
 362                 ns->pages[i].byte = NULL;
 363         }
 364
 365         return 0;
 366 }
 367
 368 /*
 369  * Free any allocated pages, and free the array of page pointers.
 370  */
 371 static void free_device(struct nandsim *ns)
 372 {
 373         int i;
 374
 375         if (ns->pages) {
 376                 for (i = 0; i < ns->geom.pgnum; i++) {
 377                         if (ns->pages[i].byte)
 378                                 kfree(ns->pages[i].byte);
 379                 }
 380                 vfree(ns->pages);
 381         }
 382 }
 383
 384 /*
 385  * Initialize the nandsim structure.
 386  *
 387  * RETURNS: 0 if success, -ERRNO if failure.
 388  */
 389 static int init_nandsim(struct mtd_info *mtd)
 390 {
 391         struct nand_chip *chip = (struct nand_chip *)mtd->priv;
 392         struct nandsim   *ns   = (struct nandsim *)(chip->priv);
 393         int i;
 394
 395         if (NS_IS_INITIALIZED(ns)) {
 396                 NS_ERR("init_nandsim: nandsim is already initialized\n");
 397                 return -EIO;
 398         }
 399
 400         /* Force mtd to not do delays */
 401         chip->chip_delay = 0;
 402
 403         /* Initialize the NAND flash parameters */
 404         ns->busw = chip->options & NAND_BUSWIDTH_16 ? 16 : 8;
 405         ns->geom.totsz    = mtd->size;
 406         ns->geom.pgsz     = mtd->writesize;
 407         ns->geom.oobsz    = mtd->oobsize;
 408         ns->geom.secsz    = mtd->erasesize;
 409         ns->geom.pgszoob  = ns->geom.pgsz + ns->geom.oobsz;
 410         ns->geom.pgnum    = ns->geom.totsz / ns->geom.pgsz;
 411         ns->geom.totszoob = ns->geom.totsz + ns->geom.pgnum * ns->geom.oobsz;
 412         ns->geom.secshift = ffs(ns->geom.secsz) - 1;
 413         ns->geom.pgshift  = chip->page_shift;
 414         ns->geom.oobshift = ffs(ns->geom.oobsz) - 1;
 415         ns->geom.pgsec    = ns->geom.secsz / ns->geom.pgsz;
 416         ns->geom.secszoob = ns->geom.secsz + ns->geom.oobsz * ns->geom.pgsec;
 417         ns->options = 0;
 418
 419         if (ns->geom.pgsz == 256) {
 420                 ns->options |= OPT_PAGE256;
 421         }
 422         else if (ns->geom.pgsz == 512) {
 423                 ns->options |= (OPT_PAGE512 | OPT_AUTOINCR);
 424                 if (ns->busw == 8)
 425                         ns->options |= OPT_PAGE512_8BIT;
 426         } else if (ns->geom.pgsz == 2048) {
 427                 ns->options |= OPT_PAGE2048;
 428         } else {
 429                 NS_ERR("init_nandsim: unknown page size %u\n", ns->geom.pgsz);
 430                 return -EIO;
 431         }
 432
 433         if (ns->options & OPT_SMALLPAGE) {
 434                 if (ns->geom.totsz < (64 << 20)) {
 435                         ns->geom.pgaddrbytes  = 3;
 436                         ns->geom.secaddrbytes = 2;
 437                 } else {
 438                         ns->geom.pgaddrbytes  = 4;
 439                         ns->geom.secaddrbytes = 3;
 440                 }
 441         } else {
 442                 if (ns->geom.totsz <= (128 << 20)) {
 443                         ns->geom.pgaddrbytes  = 5;
 444                         ns->geom.secaddrbytes = 2;
 445                 } else {
 446                         ns->geom.pgaddrbytes  = 5;
 447                         ns->geom.secaddrbytes = 3;
 448                 }
 449         }
 450
 451         /* Detect how many ID bytes the NAND chip outputs */
 452         for (i = 0; nand_flash_ids[i].name != NULL; i++) {
 453                 if (second_id_byte != nand_flash_ids[i].id)
 454                         continue;
 455                 if (!(nand_flash_ids[i].options & NAND_NO_AUTOINCR))
 456                         ns->options |= OPT_AUTOINCR;
 457         }
 458
 459         if (ns->busw == 16)
 460                 NS_WARN("16-bit flashes support wasn't tested\n");
 461
 462         printk("flash size: %u MiB\n",          ns->geom.totsz >> 20);
 463         printk("page size: %u bytes\n",         ns->geom.pgsz);
 464         printk("OOB area size: %u bytes\n",     ns->geom.oobsz);
 465         printk("sector size: %u KiB\n",         ns->geom.secsz >> 10);
 466         printk("pages number: %u\n",            ns->geom.pgnum);
 467         printk("pages per sector: %u\n",        ns->geom.pgsec);
 468         printk("bus width: %u\n",               ns->busw);
 469         printk("bits in sector size: %u\n",     ns->geom.secshift);
 470         printk("bits in page size: %u\n",       ns->geom.pgshift);
 471         printk("bits in OOB size: %u\n",        ns->geom.oobshift);
 472         printk("flash size with OOB: %u KiB\n", ns->geom.totszoob >> 10);
 473         printk("page address bytes: %u\n",      ns->geom.pgaddrbytes);
 474         printk("sector address bytes: %u\n",    ns->geom.secaddrbytes);
 475         printk("options: %#x\n",                ns->options);
 476
 477         if (alloc_device(ns) != 0)
 478                 goto error;
 479
 480         /* Allocate / initialize the internal buffer */
 481         ns->buf.byte = kmalloc(ns->geom.pgszoob, GFP_KERNEL);
 482         if (!ns->buf.byte) {
 483                 NS_ERR("init_nandsim: unable to allocate %u bytes for the internal buffer\n",
 484                         ns->geom.pgszoob);
 485                 goto error;
 486         }
 487         memset(ns->buf.byte, 0xFF, ns->geom.pgszoob);
 488
 489         /* Fill the partition_info structure */
 490         ns->part.name   = "NAND simulator partition";
 491         ns->part.offset = 0;
 492         ns->part.size   = ns->geom.totsz;
 493
 494         return 0;
 495
 496 error:
 497         free_device(ns);
 498
 499         return -ENOMEM;
 500 }
 501
 502 /*
 503  * Free the nandsim structure.
 504  */
 505 static void free_nandsim(struct nandsim *ns)
 506 {
 507         kfree(ns->buf.byte);
 508         free_device(ns);
 509
 510         return;
 511 }
 512
 513 /*
 514  * Returns the string representation of 'state' state.
 515  */
 516 static char *get_state_name(uint32_t state)
 517 {
 518         switch (NS_STATE(state)) {
 519                 case STATE_CMD_READ0:
 520                         return "STATE_CMD_READ0";
 521                 case STATE_CMD_READ1:
 522                         return "STATE_CMD_READ1";
 523                 case STATE_CMD_PAGEPROG:
 524                         return "STATE_CMD_PAGEPROG";
 525                 case STATE_CMD_READOOB:
 526                         return "STATE_CMD_READOOB";
 527                 case STATE_CMD_READSTART:
 528                         return "STATE_CMD_READSTART";
 529                 case STATE_CMD_ERASE1:
 530                         return "STATE_CMD_ERASE1";
 531                 case STATE_CMD_STATUS:
 532                         return "STATE_CMD_STATUS";
 533                 case STATE_CMD_STATUS_M:
 534                         return "STATE_CMD_STATUS_M";
 535                 case STATE_CMD_SEQIN:
 536                         return "STATE_CMD_SEQIN";
 537                 case STATE_CMD_READID:
 538                         return "STATE_CMD_READID";
 539                 case STATE_CMD_ERASE2:
 540                         return "STATE_CMD_ERASE2";
 541                 case STATE_CMD_RESET:
 542                         return "STATE_CMD_RESET";
 543                 case STATE_ADDR_PAGE:
 544                         return "STATE_ADDR_PAGE";
 545                 case STATE_ADDR_SEC:
 546                         return "STATE_ADDR_SEC";
 547                 case STATE_ADDR_ZERO:
 548                         return "STATE_ADDR_ZERO";
 549                 case STATE_DATAIN:
 550                         return "STATE_DATAIN";
 551                 case STATE_DATAOUT:
 552                         return "STATE_DATAOUT";
 553                 case STATE_DATAOUT_ID:
 554                         return "STATE_DATAOUT_ID";
 555                 case STATE_DATAOUT_STATUS:
 556                         return "STATE_DATAOUT_STATUS";
 557                 case STATE_DATAOUT_STATUS_M:
 558                         return "STATE_DATAOUT_STATUS_M";
 559                 case STATE_READY:
 560                         return "STATE_READY";
 561                 case STATE_UNKNOWN:
 562                         return "STATE_UNKNOWN";
 563         }
 564
 565         NS_ERR("get_state_name: unknown state, BUG\n");
 566         return NULL;
 567 }
 568
 569 /*
 570  * Check if command is valid.
 571  *
 572  * RETURNS: 1 if wrong command, 0 if right.
 573  */
 574 static int check_command(int cmd)
 575 {
 576         switch (cmd) {
 577
 578         case NAND_CMD_READ0:
 579         case NAND_CMD_READSTART:
 580         case NAND_CMD_PAGEPROG:
 581         case NAND_CMD_READOOB:
 582         case NAND_CMD_ERASE1:
 583         case NAND_CMD_STATUS:
 584         case NAND_CMD_SEQIN:
 585         case NAND_CMD_READID:
 586         case NAND_CMD_ERASE2:
 587         case NAND_CMD_RESET:
 588         case NAND_CMD_READ1:
 589                 return 0;
 590
 591         case NAND_CMD_STATUS_MULTI:
 592         default:
 593                 return 1;
 594         }
 595 }
 596
 597 /*
 598  * Returns state after command is accepted by command number.
 599  */
 600 static uint32_t get_state_by_command(unsigned command)
 601 {
 602         switch (command) {
 603                 case NAND_CMD_READ0:
 604                         return STATE_CMD_READ0;
 605                 case NAND_CMD_READ1:
 606                         return STATE_CMD_READ1;
 607                 case NAND_CMD_PAGEPROG:
 608                         return STATE_CMD_PAGEPROG;
 609                 case NAND_CMD_READSTART:
 610                         return STATE_CMD_READSTART;
 611                 case NAND_CMD_READOOB:
 612                         return STATE_CMD_READOOB;
 613                 case NAND_CMD_ERASE1:
 614                         return STATE_CMD_ERASE1;
 615                 case NAND_CMD_STATUS:
 616                         return STATE_CMD_STATUS;
 617                 case NAND_CMD_STATUS_MULTI:
 618                         return STATE_CMD_STATUS_M;
 619                 case NAND_CMD_SEQIN:
 620                         return STATE_CMD_SEQIN;
 621                 case NAND_CMD_READID:
 622                         return STATE_CMD_READID;
 623                 case NAND_CMD_ERASE2:
 624                         return STATE_CMD_ERASE2;
 625                 case NAND_CMD_RESET:
 626                         return STATE_CMD_RESET;
 627         }
 628
 629         NS_ERR("get_state_by_command: unknown command, BUG\n");
 630         return 0;
 631 }
 632
 633 /*
 634  * Move an address byte to the correspondent internal register.
 635  */
 636 static inline void accept_addr_byte(struct nandsim *ns, u_char bt)
 637 {
 638         uint byte = (uint)bt;
 639
 640         if (ns->regs.count < (ns->geom.pgaddrbytes - ns->geom.secaddrbytes))
 641                 ns->regs.column |= (byte << 8 * ns->regs.count);
 642         else {
 643                 ns->regs.row |= (byte << 8 * (ns->regs.count -
 644                                                 ns->geom.pgaddrbytes +
 645                                                 ns->geom.secaddrbytes));
 646         }
 647
 648         return;
 649 }
 650
 651 /*
 652  * Switch to STATE_READY state.
 653  */
 654 static inline void switch_to_ready_state(struct nandsim *ns, u_char status)
 655 {
 656         NS_DBG("switch_to_ready_state: switch to %s state\n", get_state_name(STATE_READY));
 657
 658         ns->state       = STATE_READY;
 659         ns->nxstate     = STATE_UNKNOWN;
 660         ns->op          = NULL;
 661         ns->npstates    = 0;
 662         ns->stateidx    = 0;
 663         ns->regs.num    = 0;
 664         ns->regs.count  = 0;
 665         ns->regs.off    = 0;
 666         ns->regs.row    = 0;
 667         ns->regs.column = 0;
 668         ns->regs.status = status;
 669 }
 670
 671 /*
 672  * If the operation isn't known yet, try to find it in the global array
 673  * of supported operations.
 674  *
 675  * Operation can be unknown because of the following.
 676  *   1. New command was accepted and this is the firs call to find the
 677  *      correspondent states chain. In this case ns->npstates = 0;
 678  *   2. There is several operations which begin with the same command(s)
 679  *      (for example program from the second half and read from the
 680  *      second half operations both begin with the READ1 command). In this
 681  *      case the ns->pstates[] array contains previous states.
 682  *
 683  * Thus, the function tries to find operation containing the following
 684  * states (if the 'flag' parameter is 0):
 685  *    ns->pstates[0], ... ns->pstates[ns->npstates], ns->state
 686  *
 687  * If (one and only one) matching operation is found, it is accepted (
 688  * ns->ops, ns->state, ns->nxstate are initialized, ns->npstate is
 689  * zeroed).
 690  *
 691  * If there are several maches, the current state is pushed to the
 692  * ns->pstates.
 693  *
 694  * The operation can be unknown only while commands are input to the chip.
 695  * As soon as address command is accepted, the operation must be known.
 696  * In such situation the function is called with 'flag' != 0, and the
 697  * operation is searched using the following pattern:
 698  *     ns->pstates[0], ... ns->pstates[ns->npstates], <address input>
 699  *
 700  * It is supposed that this pattern must either match one operation on
 701  * none. There can't be ambiguity in that case.
 702  *
 703  * If no matches found, the functions does the following:
 704  *   1. if there are saved states present, try to ignore them and search
 705  *      again only using the last command. If nothing was found, switch
 706  *      to the STATE_READY state.
 707  *   2. if there are no saved states, switch to the STATE_READY state.
 708  *
 709  * RETURNS: -2 - no matched operations found.
 710  *          -1 - several matches.
 711  *           0 - operation is found.
 712  */
 713 static int find_operation(struct nandsim *ns, uint32_t flag)
 714 {
 715         int opsfound = 0;
 716         int i, j, idx = 0;
 717
 718         for (i = 0; i < NS_OPER_NUM; i++) {
 719
 720                 int found = 1;
 721
 722                 if (!(ns->options & ops[i].reqopts))
 723                         /* Ignore operations we can't perform */
 724                         continue;
 725
 726                 if (flag) {
 727                         if (!(ops[i].states[ns->npstates] & STATE_ADDR_MASK))
 728                                 continue;
 729                 } else {
 730                         if (NS_STATE(ns->state) != NS_STATE(ops[i].states[ns->npstates]))
 731                                 continue;
 732                 }
 733
 734                 for (j = 0; j < ns->npstates; j++)
 735                         if (NS_STATE(ops[i].states[j]) != NS_STATE(ns->pstates[j])
 736                                 && (ns->options & ops[idx].reqopts)) {
 737                                 found = 0;
 738                                 break;
 739                         }
 740
 741                 if (found) {
 742                         idx = i;
 743                         opsfound += 1;
 744                 }
 745         }
 746
 747         if (opsfound == 1) {
 748                 /* Exact match */
 749                 ns->op = &ops[idx].states[0];
 750                 if (flag) {
 751                         /*
 752                          * In this case the find_operation function was
 753                          * called when address has just began input. But it isn't
 754                          * yet fully input and the current state must
 755                          * not be one of STATE_ADDR_*, but the STATE_ADDR_*
 756                          * state must be the next state (ns->nxstate).
 757                          */
 758                         ns->stateidx = ns->npstates - 1;
 759                 } else {
 760                         ns->stateidx = ns->npstates;
 761                 }
 762                 ns->npstates = 0;
 763                 ns->state = ns->op[ns->stateidx];
 764                 ns->nxstate = ns->op[ns->stateidx + 1];
 765                 NS_DBG("find_operation: operation found, index: %d, state: %s, nxstate %s\n",
 766                                 idx, get_state_name(ns->state), get_state_name(ns->nxstate));
 767                 return 0;
 768         }
 769
 770         if (opsfound == 0) {
 771                 /* Nothing was found. Try to ignore previous commands (if any) and search again */
 772                 if (ns->npstates != 0) {
 773                         NS_DBG("find_operation: no operation found, try again with state %s\n",
 774                                         get_state_name(ns->state));
 775                         ns->npstates = 0;
 776                         return find_operation(ns, 0);
 777
 778                 }
 779                 NS_DBG("find_operation: no operations found\n");
 780                 switch_to_ready_state(ns, NS_STATUS_FAILED(ns));
 781                 return -2;
 782         }
 783
 784         if (flag) {
 785                 /* This shouldn't happen */
 786                 NS_DBG("find_operation: BUG, operation must be known if address is input\n");
 787                 return -2;
 788         }
 789
 790         NS_DBG("find_operation: there is still ambiguity\n");
 791
 792         ns->pstates[ns->npstates++] = ns->state;
 793
 794         return -1;
 795 }
 796
 797 /*
 798  * Returns a pointer to the current page.
 799  */
 800 static inline union ns_mem *NS_GET_PAGE(struct nandsim *ns)
 801 {
 802         return &(ns->pages[ns->regs.row]);
 803 }
 804
 805 /*
 806  * Retuns a pointer to the current byte, within the current page.
 807  */
 808 static inline u_char *NS_PAGE_BYTE_OFF(struct nandsim *ns)
 809 {
 810         return NS_GET_PAGE(ns)->byte + ns->regs.column + ns->regs.off;
 811 }
 812
 813 /*
 814  * Fill the NAND buffer with data read from the specified page.
 815  */
 816 static void read_page(struct nandsim *ns, int num)
 817 {
 818         union ns_mem *mypage;
 819
 820         mypage = NS_GET_PAGE(ns);
 821         if (mypage->byte == NULL) {
 822                 NS_DBG("read_page: page %d not allocated\n", ns->regs.row);
 823                 memset(ns->buf.byte, 0xFF, num);
 824         } else {
 825                 NS_DBG("read_page: page %d allocated, reading from %d\n",
 826                         ns->regs.row, ns->regs.column + ns->regs.off);
 827                 memcpy(ns->buf.byte, NS_PAGE_BYTE_OFF(ns), num);
 828         }
 829 }
 830
 831 /*
 832  * Erase all pages in the specified sector.
 833  */
 834 static void erase_sector(struct nandsim *ns)
 835 {
 836         union ns_mem *mypage;
 837         int i;
 838
 839         mypage = NS_GET_PAGE(ns);
 840         for (i = 0; i < ns->geom.pgsec; i++) {
 841                 if (mypage->byte != NULL) {
 842                         NS_DBG("erase_sector: freeing page %d\n", ns->regs.row+i);
 843                         kfree(mypage->byte);
 844                         mypage->byte = NULL;
 845                 }
 846                 mypage++;
 847         }
 848 }
 849
 850 /*
 851  * Program the specified page with the contents from the NAND buffer.
 852  */
 853 static int prog_page(struct nandsim *ns, int num)
 854 {
 855         union ns_mem *mypage;
 856         u_char *pg_off;
 857
 858         mypage = NS_GET_PAGE(ns);
 859         if (mypage->byte == NULL) {
 860                 NS_DBG("prog_page: allocating page %d\n", ns->regs.row);
 861                 mypage->byte = kmalloc(ns->geom.pgszoob, GFP_KERNEL);
 862                 if (mypage->byte == NULL) {
 863                         NS_ERR("prog_page: error allocating memory for page %d\n", ns->regs.row);
 864                         return -1;
 865                 }
 866                 memset(mypage->byte, 0xFF, ns->geom.pgszoob);
 867         }
 868
 869         pg_off = NS_PAGE_BYTE_OFF(ns);
 870         memcpy(pg_off, ns->buf.byte, num);
 871
 872         return 0;
 873 }
 874
 875 /*
 876  * If state has any action bit, perform this action.
 877  *
 878  * RETURNS: 0 if success, -1 if error.
 879  */
 880 static int do_state_action(struct nandsim *ns, uint32_t action)
 881 {
 882         int num;
 883         int busdiv = ns->busw == 8 ? 1 : 2;
 884
 885         action &= ACTION_MASK;
 886
 887         /* Check that page address input is correct */
 888         if (action != ACTION_SECERASE && ns->regs.row >= ns->geom.pgnum) {
 889                 NS_WARN("do_state_action: wrong page number (%#x)\n", ns->regs.row);
 890                 return -1;
 891         }
 892
 893         switch (action) {
 894
 895         case ACTION_CPY:
 896                 /*
 897                  * Copy page data to the internal buffer.
 898                  */
 899
 900                 /* Column shouldn't be very large */
 901                 if (ns->regs.column >= (ns->geom.pgszoob - ns->regs.off)) {
 902                         NS_ERR("do_state_action: column number is too large\n");
 903                         break;
 904                 }
 905                 num = ns->geom.pgszoob - ns->regs.off - ns->regs.column;
 906                 read_page(ns, num);
 907
 908                 NS_DBG("do_state_action: (ACTION_CPY:) copy %d bytes to int buf, raw offset %d\n",
 909                         num, NS_RAW_OFFSET(ns) + ns->regs.off);
 910
 911                 if (ns->regs.off == 0)
 912                         NS_LOG("read page %d\n", ns->regs.row);
 913                 else if (ns->regs.off < ns->geom.pgsz)
 914                         NS_LOG("read page %d (second half)\n", ns->regs.row);
 915                 else
 916                         NS_LOG("read OOB of page %d\n", ns->regs.row);
 917
 918                 NS_UDELAY(access_delay);
 919                 NS_UDELAY(input_cycle * ns->geom.pgsz / 1000 / busdiv);
 920
 921                 break;
 922
 923         case ACTION_SECERASE:
 924                 /*
 925                  * Erase sector.
 926                  */
 927
 928                 if (ns->lines.wp) {
 929                         NS_ERR("do_state_action: device is write-protected, ignore sector erase\n");
 930                         return -1;
 931                 }
 932
 933                 if (ns->regs.row >= ns->geom.pgnum - ns->geom.pgsec
 934                         || (ns->regs.row & ~(ns->geom.secsz - 1))) {
 935                         NS_ERR("do_state_action: wrong sector address (%#x)\n", ns->regs.row);
 936                         return -1;
 937                 }
 938
 939                 ns->regs.row = (ns->regs.row <<
 940                                 8 * (ns->geom.pgaddrbytes - ns->geom.secaddrbytes)) | ns->regs.column;
 941                 ns->regs.column = 0;
 942
 943                 NS_DBG("do_state_action: erase sector at address %#x, off = %d\n",
 944                                 ns->regs.row, NS_RAW_OFFSET(ns));
 945                 NS_LOG("erase sector %d\n", ns->regs.row >> (ns->geom.secshift - ns->geom.pgshift));
 946
 947                 erase_sector(ns);
 948
 949                 NS_MDELAY(erase_delay);
 950
 951                 break;
 952
 953         case ACTION_PRGPAGE:
 954                 /*
 955                  * Programm page - move internal buffer data to the page.
 956                  */
 957
 958                 if (ns->lines.wp) {
 959                         NS_WARN("do_state_action: device is write-protected, programm\n");
 960                         return -1;
 961                 }
 962
 963                 num = ns->geom.pgszoob - ns->regs.off - ns->regs.column;
 964                 if (num != ns->regs.count) {
 965                         NS_ERR("do_state_action: too few bytes were input (%d instead of %d)\n",
 966                                         ns->regs.count, num);
 967                         return -1;
 968                 }
 969
 970                 if (prog_page(ns, num) == -1)
 971                         return -1;
 972
 973                 NS_DBG("do_state_action: copy %d bytes from int buf to (%#x, %#x), raw off = %d\n",
 974                         num, ns->regs.row, ns->regs.column, NS_RAW_OFFSET(ns) + ns->regs.off);
 975                 NS_LOG("programm page %d\n", ns->regs.row);
 976
 977                 NS_UDELAY(programm_delay);
 978                 NS_UDELAY(output_cycle * ns->geom.pgsz / 1000 / busdiv);
 979
 980                 break;
 981
 982         case ACTION_ZEROOFF:
 983                 NS_DBG("do_state_action: set internal offset to 0\n");
 984                 ns->regs.off = 0;
 985                 break;
 986
 987         case ACTION_HALFOFF:
 988                 if (!(ns->options & OPT_PAGE512_8BIT)) {
 989                         NS_ERR("do_state_action: BUG! can't skip half of page for non-512"
 990                                 "byte page size 8x chips\n");
 991                         return -1;
 992                 }
 993                 NS_DBG("do_state_action: set internal offset to %d\n", ns->geom.pgsz/2);
 994                 ns->regs.off = ns->geom.pgsz/2;
 995                 break;
 996
 997         case ACTION_OOBOFF:
 998                 NS_DBG("do_state_action: set internal offset to %d\n", ns->geom.pgsz);
 999                 ns->regs.off = ns->geom.pgsz;
1000                 break;
1001
1002         default:
1003                 NS_DBG("do_state_action: BUG! unknown action\n");
1004         }
1005
1006         return 0;
1007 }
1008
1009 /*
1010  * Switch simulator's state.
1011  */
1012 static void switch_state(struct nandsim *ns)
1013 {
1014         if (ns->op) {
1015                 /*
1016                  * The current operation have already been identified.
1017                  * Just follow the states chain.
1018                  */
1019
1020                 ns->stateidx += 1;
1021                 ns->state = ns->nxstate;
1022                 ns->nxstate = ns->op[ns->stateidx + 1];
1023
1024                 NS_DBG("switch_state: operation is known, switch to the next state, "
1025                         "state: %s, nxstate: %s\n",
1026                         get_state_name(ns->state), get_state_name(ns->nxstate));
1027
1028                 /* See, whether we need to do some action */
1029                 if ((ns->state & ACTION_MASK) && do_state_action(ns, ns->state) < 0) {
1030                         switch_to_ready_state(ns, NS_STATUS_FAILED(ns));
1031                         return;
1032                 }
1033
1034         } else {
1035                 /*
1036                  * We don't yet know which operation we perform.
1037                  * Try to identify it.
1038                  */
1039
1040                 /*
1041                  *  The only event causing the switch_state function to
1042                  *  be called with yet unknown operation is new command.
1043                  */
1044                 ns->state = get_state_by_command(ns->regs.command);
1045
1046                 NS_DBG("switch_state: operation is unknown, try to find it\n");
1047
1048                 if (find_operation(ns, 0) != 0)
1049                         return;
1050
1051                 if ((ns->state & ACTION_MASK) && do_state_action(ns, ns->state) < 0) {
1052                         switch_to_ready_state(ns, NS_STATUS_FAILED(ns));
1053                         return;
1054                 }
1055         }
1056
1057         /* For 16x devices column means the page offset in words */
1058         if ((ns->nxstate & STATE_ADDR_MASK) && ns->busw == 16) {
1059                 NS_DBG("switch_state: double the column number for 16x device\n");
1060                 ns->regs.column <<= 1;
1061         }
1062
1063         if (NS_STATE(ns->nxstate) == STATE_READY) {
1064                 /*
1065                  * The current state is the last. Return to STATE_READY
1066                  */
1067
1068                 u_char status = NS_STATUS_OK(ns);
1069
1070                 /* In case of data states, see if all bytes were input/output */
1071                 if ((ns->state & (STATE_DATAIN_MASK | STATE_DATAOUT_MASK))
1072                         && ns->regs.count != ns->regs.num) {
1073                         NS_WARN("switch_state: not all bytes were processed, %d left\n",
1074                                         ns->regs.num - ns->regs.count);
1075                         status = NS_STATUS_FAILED(ns);
1076                 }
1077
1078                 NS_DBG("switch_state: operation complete, switch to STATE_READY state\n");
1079
1080                 switch_to_ready_state(ns, status);
1081
1082                 return;
1083         } else if (ns->nxstate & (STATE_DATAIN_MASK | STATE_DATAOUT_MASK)) {
1084                 /*
1085                  * If the next state is data input/output, switch to it now
1086                  */
1087
1088                 ns->state      = ns->nxstate;
1089                 ns->nxstate    = ns->op[++ns->stateidx + 1];
1090                 ns->regs.num   = ns->regs.count = 0;
1091
1092                 NS_DBG("switch_state: the next state is data I/O, switch, "
1093                         "state: %s, nxstate: %s\n",
1094                         get_state_name(ns->state), get_state_name(ns->nxstate));
1095
1096                 /*
1097                  * Set the internal register to the count of bytes which
1098                  * are expected to be input or output
1099                  */
1100                 switch (NS_STATE(ns->state)) {
1101                         case STATE_DATAIN:
1102                         case STATE_DATAOUT:
1103                                 ns->regs.num = ns->geom.pgszoob - ns->regs.off - ns->regs.column;
1104                                 break;
1105
1106                         case STATE_DATAOUT_ID:
1107                                 ns->regs.num = ns->geom.idbytes;
1108                                 break;
1109
1110                         case STATE_DATAOUT_STATUS:
1111                         case STATE_DATAOUT_STATUS_M:
1112                                 ns->regs.count = ns->regs.num = 0;
1113                                 break;
1114
1115                         default:
1116                                 NS_ERR("switch_state: BUG! unknown data state\n");
1117                 }
1118
1119         } else if (ns->nxstate & STATE_ADDR_MASK) {
1120                 /*
1121                  * If the next state is address input, set the internal
1122                  * register to the number of expected address bytes
1123                  */
1124
1125                 ns->regs.count = 0;
1126
1127                 switch (NS_STATE(ns->nxstate)) {
1128                         case STATE_ADDR_PAGE:
1129                                 ns->regs.num = ns->geom.pgaddrbytes;
1130
1131                                 break;
1132                         case STATE_ADDR_SEC:
1133                                 ns->regs.num = ns->geom.secaddrbytes;
1134                                 break;
1135
1136                         case STATE_ADDR_ZERO:
1137                                 ns->regs.num = 1;
1138                                 break;
1139
1140                         default:
1141                                 NS_ERR("switch_state: BUG! unknown address state\n");
1142                 }
1143         } else {
1144                 /*
1145                  * Just reset internal counters.
1146                  */
1147
1148                 ns->regs.num = 0;
1149                 ns->regs.count = 0;
1150         }
1151 }
1152
1153 static u_char ns_nand_read_byte(struct mtd_info *mtd)
1154 {
1155         struct nandsim *ns = (struct nandsim *)((struct nand_chip *)mtd->priv)->priv;
1156         u_char outb = 0x00;
1157
1158         /* Sanity and correctness checks */
1159         if (!ns->lines.ce) {
1160                 NS_ERR("read_byte: chip is disabled, return %#x\n", (uint)outb);
1161                 return outb;
1162         }
1163         if (ns->lines.ale || ns->lines.cle) {
1164                 NS_ERR("read_byte: ALE or CLE pin is high, return %#x\n", (uint)outb);
1165                 return outb;
1166         }
1167         if (!(ns->state & STATE_DATAOUT_MASK)) {
1168                 NS_WARN("read_byte: unexpected data output cycle, state is %s "
1169                         "return %#x\n", get_state_name(ns->state), (uint)outb);
1170                 return outb;
1171         }
1172
1173         /* Status register may be read as many times as it is wanted */
1174         if (NS_STATE(ns->state) == STATE_DATAOUT_STATUS) {
1175                 NS_DBG("read_byte: return %#x status\n", ns->regs.status);
1176                 return ns->regs.status;
1177         }
1178
1179         /* Check if there is any data in the internal buffer which may be read */
1180         if (ns->regs.count == ns->regs.num) {
1181                 NS_WARN("read_byte: no more data to output, return %#x\n", (uint)outb);
1182                 return outb;
1183         }
1184
1185         switch (NS_STATE(ns->state)) {
1186                 case STATE_DATAOUT:
1187                         if (ns->busw == 8) {
1188                                 outb = ns->buf.byte[ns->regs.count];
1189                                 ns->regs.count += 1;
1190                         } else {
1191                                 outb = (u_char)cpu_to_le16(ns->buf.word[ns->regs.count >> 1]);
1192                                 ns->regs.count += 2;
1193                         }
1194                         break;
1195                 case STATE_DATAOUT_ID:
1196                         NS_DBG("read_byte: read ID byte %d, total = %d\n", ns->regs.count, ns->regs.num);
1197                         outb = ns->ids[ns->regs.count];
1198                         ns->regs.count += 1;
1199                         break;
1200                 default:
1201                         BUG();
1202         }
1203
1204         if (ns->regs.count == ns->regs.num) {
1205                 NS_DBG("read_byte: all bytes were read\n");
1206
1207                 /*
1208                  * The OPT_AUTOINCR allows to read next conseqitive pages without
1209                  * new read operation cycle.
1210                  */
1211                 if ((ns->options & OPT_AUTOINCR) && NS_STATE(ns->state) == STATE_DATAOUT) {
1212                         ns->regs.count = 0;
1213                         if (ns->regs.row + 1 < ns->geom.pgnum)
1214                                 ns->regs.row += 1;
1215                         NS_DBG("read_byte: switch to the next page (%#x)\n", ns->regs.row);
1216                         do_state_action(ns, ACTION_CPY);
1217                 }
1218                 else if (NS_STATE(ns->nxstate) == STATE_READY)
1219                         switch_state(ns);
1220
1221         }
1222
1223         return outb;
1224 }
1225
1226 static void ns_nand_write_byte(struct mtd_info *mtd, u_char byte)
1227 {
1228         struct nandsim *ns = (struct nandsim *)((struct nand_chip *)mtd->priv)->priv;
1229
1230         /* Sanity and correctness checks */
1231         if (!ns->lines.ce) {
1232                 NS_ERR("write_byte: chip is disabled, ignore write\n");
1233                 return;
1234         }
1235         if (ns->lines.ale && ns->lines.cle) {
1236                 NS_ERR("write_byte: ALE and CLE pins are high simultaneously, ignore write\n");
1237                 return;
1238         }
1239
1240         if (ns->lines.cle == 1) {
1241                 /*
1242                  * The byte written is a command.
1243                  */
1244
1245                 if (byte == NAND_CMD_RESET) {
1246                         NS_LOG("reset chip\n");
1247                         switch_to_ready_state(ns, NS_STATUS_OK(ns));
1248                         return;
1249                 }
1250
1251                 /*
1252                  * Chip might still be in STATE_DATAOUT
1253                  * (if OPT_AUTOINCR feature is supported), STATE_DATAOUT_STATUS or
1254                  * STATE_DATAOUT_STATUS_M state. If so, switch state.
1255                  */
1256                 if (NS_STATE(ns->state) == STATE_DATAOUT_STATUS
1257                         || NS_STATE(ns->state) == STATE_DATAOUT_STATUS_M
1258                         || ((ns->options & OPT_AUTOINCR) && NS_STATE(ns->state) == STATE_DATAOUT))
1259                         switch_state(ns);
1260
1261                 /* Check if chip is expecting command */
1262                 if (NS_STATE(ns->nxstate) != STATE_UNKNOWN && !(ns->nxstate & STATE_CMD_MASK)) {
1263                         /*
1264                          * We are in situation when something else (not command)
1265                          * was expected but command was input. In this case ignore
1266                          * previous command(s)/state(s) and accept the last one.
1267                          */
1268                         NS_WARN("write_byte: command (%#x) wasn't expected, expected state is %s, "
1269                                 "ignore previous states\n", (uint)byte, get_state_name(ns->nxstate));
1270                         switch_to_ready_state(ns, NS_STATUS_FAILED(ns));
1271                 }
1272
1273                 /* Check that the command byte is correct */
1274                 if (check_command(byte)) {
1275                         NS_ERR("write_byte: unknown command %#x\n", (uint)byte);
1276                         return;
1277                 }
1278
1279                 NS_DBG("command byte corresponding to %s state accepted\n",
1280                         get_state_name(get_state_by_command(byte)));
1281                 ns->regs.command = byte;
1282                 switch_state(ns);
1283
1284         } else if (ns->lines.ale == 1) {
1285                 /*
1286                  * The byte written is an address.
1287                  */
1288
1289                 if (NS_STATE(ns->nxstate) == STATE_UNKNOWN) {
1290
1291                         NS_DBG("write_byte: operation isn't known yet, identify it\n");
1292
1293                         if (find_operation(ns, 1) < 0)
1294                                 return;
1295
1296                         if ((ns->state & ACTION_MASK) && do_state_action(ns, ns->state) < 0) {
1297                                 switch_to_ready_state(ns, NS_STATUS_FAILED(ns));
1298                                 return;
1299                         }
1300
1301                         ns->regs.count = 0;
1302                         switch (NS_STATE(ns->nxstate)) {
1303                                 case STATE_ADDR_PAGE:
1304                                         ns->regs.num = ns->geom.pgaddrbytes;
1305                                         break;
1306                                 case STATE_ADDR_SEC:
1307                                         ns->regs.num = ns->geom.secaddrbytes;
1308                                         break;
1309                                 case STATE_ADDR_ZERO:
1310                                         ns->regs.num = 1;
1311                                         break;
1312                                 default:
1313                                         BUG();
1314                         }
1315                 }
1316
1317                 /* Check that chip is expecting address */
1318                 if (!(ns->nxstate & STATE_ADDR_MASK)) {
1319                         NS_ERR("write_byte: address (%#x) isn't expected, expected state is %s, "
1320                                 "switch to STATE_READY\n", (uint)byte, get_state_name(ns->nxstate));
1321                         switch_to_ready_state(ns, NS_STATUS_FAILED(ns));
1322                         return;
1323                 }
1324
1325                 /* Check if this is expected byte */
1326                 if (ns->regs.count == ns->regs.num) {
1327                         NS_ERR("write_byte: no more address bytes expected\n");
1328                         switch_to_ready_state(ns, NS_STATUS_FAILED(ns));
1329                         return;
1330                 }
1331
1332                 accept_addr_byte(ns, byte);
1333
1334                 ns->regs.count += 1;
1335
1336                 NS_DBG("write_byte: address byte %#x was accepted (%d bytes input, %d expected)\n",
1337                                 (uint)byte, ns->regs.count, ns->regs.num);
1338
1339                 if (ns->regs.count == ns->regs.num) {
1340                         NS_DBG("address (%#x, %#x) is accepted\n", ns->regs.row, ns->regs.column);
1341                         switch_state(ns);
1342                 }
1343
1344         } else {
1345                 /*
1346                  * The byte written is an input data.
1347                  */
1348
1349                 /* Check that chip is expecting data input */
1350                 if (!(ns->state & STATE_DATAIN_MASK)) {
1351                         NS_ERR("write_byte: data input (%#x) isn't expected, state is %s, "
1352                                 "switch to %s\n", (uint)byte,
1353                                 get_state_name(ns->state), get_state_name(STATE_READY));
1354                         switch_to_ready_state(ns, NS_STATUS_FAILED(ns));
1355                         return;
1356                 }
1357
1358                 /* Check if this is expected byte */
1359                 if (ns->regs.count == ns->regs.num) {
1360                         NS_WARN("write_byte: %u input bytes has already been accepted, ignore write\n",
1361                                         ns->regs.num);
1362                         return;
1363                 }
1364
1365                 if (ns->busw == 8) {
1366                         ns->buf.byte[ns->regs.count] = byte;
1367                         ns->regs.count += 1;
1368                 } else {
1369                         ns->buf.word[ns->regs.count >> 1] = cpu_to_le16((uint16_t)byte);
1370                         ns->regs.count += 2;
1371                 }
1372         }
1373
1374         return;
1375 }
1376
1377 static void ns_hwcontrol(struct mtd_info *mtd, int cmd, unsigned int bitmask)
1378 {
1379         struct nandsim *ns = ((struct nand_chip *)mtd->priv)->priv;
1380
1381         ns->lines.cle = bitmask & NAND_CLE ? 1 : 0;
1382         ns->lines.ale = bitmask & NAND_ALE ? 1 : 0;
1383         ns->lines.ce = bitmask & NAND_NCE ? 1 : 0;
1384
1385         if (cmd != NAND_CMD_NONE)
1386                 ns_nand_write_byte(mtd, cmd);
1387 }
1388
1389 static int ns_device_ready(struct mtd_info *mtd)
1390 {
1391         NS_DBG("device_ready\n");
1392         return 1;
1393 }
1394
1395 static uint16_t ns_nand_read_word(struct mtd_info *mtd)
1396 {
1397         struct nand_chip *chip = (struct nand_chip *)mtd->priv;
1398
1399         NS_DBG("read_word\n");
1400
1401         return chip->read_byte(mtd) | (chip->read_byte(mtd) << 8);
1402 }
1403
1404 static void ns_nand_write_buf(struct mtd_info *mtd, const u_char *buf, int len)
1405 {
1406         struct nandsim *ns = (struct nandsim *)((struct nand_chip *)mtd->priv)->priv;
1407
1408         /* Check that chip is expecting data input */
1409         if (!(ns->state & STATE_DATAIN_MASK)) {
1410                 NS_ERR("write_buf: data input isn't expected, state is %s, "
1411                         "switch to STATE_READY\n", get_state_name(ns->state));
1412                 switch_to_ready_state(ns, NS_STATUS_FAILED(ns));
1413                 return;
1414         }
1415
1416         /* Check if these are expected bytes */
1417         if (ns->regs.count + len > ns->regs.num) {
1418                 NS_ERR("write_buf: too many input bytes\n");
1419                 switch_to_ready_state(ns, NS_STATUS_FAILED(ns));
1420                 return;
1421         }
1422
1423         memcpy(ns->buf.byte + ns->regs.count, buf, len);
1424         ns->regs.count += len;
1425
1426         if (ns->regs.count == ns->regs.num) {
1427                 NS_DBG("write_buf: %d bytes were written\n", ns->regs.count);
1428         }
1429 }
1430
1431 static void ns_nand_read_buf(struct mtd_info *mtd, u_char *buf, int len)
1432 {
1433         struct nandsim *ns = (struct nandsim *)((struct nand_chip *)mtd->priv)->priv;
1434
1435         /* Sanity and correctness checks */
1436         if (!ns->lines.ce) {
1437                 NS_ERR("read_buf: chip is disabled\n");
1438                 return;
1439         }
1440         if (ns->lines.ale || ns->lines.cle) {
1441                 NS_ERR("read_buf: ALE or CLE pin is high\n");
1442                 return;
1443         }
1444         if (!(ns->state & STATE_DATAOUT_MASK)) {
1445                 NS_WARN("read_buf: unexpected data output cycle, current state is %s\n",
1446                         get_state_name(ns->state));
1447                 return;
1448         }
1449
1450         if (NS_STATE(ns->state) != STATE_DATAOUT) {
1451                 int i;
1452
1453                 for (i = 0; i < len; i++)
1454                         buf[i] = ((struct nand_chip *)mtd->priv)->read_byte(mtd);
1455
1456                 return;
1457         }
1458
1459         /* Check if these are expected bytes */
1460         if (ns->regs.count + len > ns->regs.num) {
1461                 NS_ERR("read_buf: too many bytes to read\n");
1462                 switch_to_ready_state(ns, NS_STATUS_FAILED(ns));
1463                 return;
1464         }
1465
1466         memcpy(buf, ns->buf.byte + ns->regs.count, len);
1467         ns->regs.count += len;
1468
1469         if (ns->regs.count == ns->regs.num) {
1470                 if ((ns->options & OPT_AUTOINCR) && NS_STATE(ns->state) == STATE_DATAOUT) {
1471                         ns->regs.count = 0;
1472                         if (ns->regs.row + 1 < ns->geom.pgnum)
1473                                 ns->regs.row += 1;
1474                         NS_DBG("read_buf: switch to the next page (%#x)\n", ns->regs.row);
1475                         do_state_action(ns, ACTION_CPY);
1476                 }
1477                 else if (NS_STATE(ns->nxstate) == STATE_READY)
1478                         switch_state(ns);
1479         }
1480
1481         return;
1482 }
1483
1484 static int ns_nand_verify_buf(struct mtd_info *mtd, const u_char *buf, int len)
1485 {
1486         ns_nand_read_buf(mtd, (u_char *)&ns_verify_buf[0], len);
1487
1488         if (!memcmp(buf, &ns_verify_buf[0], len)) {
1489                 NS_DBG("verify_buf: the buffer is OK\n");
1490                 return 0;
1491         } else {
1492                 NS_DBG("verify_buf: the buffer is wrong\n");
1493                 return -EFAULT;
1494         }
1495 }
1496
1497 /*
1498  * Module initialization function
1499  */
1500 static int __init ns_init_module(void)
1501 {
1502         struct nand_chip *chip;
1503         struct nandsim *nand;
1504         int retval = -ENOMEM;
1505
1506         if (bus_width != 8 && bus_width != 16) {
1507                 NS_ERR("wrong bus width (%d), use only 8 or 16\n", bus_width);
1508                 return -EINVAL;
1509         }
1510
1511         /* Allocate and initialize mtd_info, nand_chip and nandsim structures */
1512         nsmtd = kmalloc(sizeof(struct mtd_info) + sizeof(struct nand_chip)
1513                                 + sizeof(struct nandsim), GFP_KERNEL);
1514         if (!nsmtd) {
1515                 NS_ERR("unable to allocate core structures.\n");
1516                 return -ENOMEM;
1517         }
1518         memset(nsmtd, 0, sizeof(struct mtd_info) + sizeof(struct nand_chip) +
1519                         sizeof(struct nandsim));
1520         chip        = (struct nand_chip *)(nsmtd + 1);
1521         nsmtd->priv = (void *)chip;
1522         nand        = (struct nandsim *)(chip + 1);
1523         chip->priv  = (void *)nand;
1524
1525         /*
1526          * Register simulator's callbacks.
1527          */
1528         chip->cmd_ctrl   = ns_hwcontrol;
1529         chip->read_byte  = ns_nand_read_byte;
1530         chip->dev_ready  = ns_device_ready;
1531         chip->write_buf  = ns_nand_write_buf;
1532         chip->read_buf   = ns_nand_read_buf;
1533         chip->verify_buf = ns_nand_verify_buf;
1534         chip->read_word  = ns_nand_read_word;
1535         chip->ecc.mode   = NAND_ECC_SOFT;
1536         chip->options   |= NAND_SKIP_BBTSCAN;
1537
1538         /*
1539          * Perform minimum nandsim structure initialization to handle
1540          * the initial ID read command correctly
1541          */
1542         if (third_id_byte != 0xFF || fourth_id_byte != 0xFF)
1543                 nand->geom.idbytes = 4;
1544         else
1545                 nand->geom.idbytes = 2;
1546         nand->regs.status = NS_STATUS_OK(nand);
1547         nand->nxstate = STATE_UNKNOWN;
1548         nand->options |= OPT_PAGE256; /* temporary value */
1549         nand->ids[0] = first_id_byte;
1550         nand->ids[1] = second_id_byte;
1551         nand->ids[2] = third_id_byte;
1552         nand->ids[3] = fourth_id_byte;
1553         if (bus_width == 16) {
1554                 nand->busw = 16;
1555                 chip->options |= NAND_BUSWIDTH_16;
1556         }
1557
1558         nsmtd->owner = THIS_MODULE;
1559
1560         if ((retval = nand_scan(nsmtd, 1)) != 0) {
1561                 NS_ERR("can't register NAND Simulator\n");
1562                 if (retval > 0)
1563                         retval = -ENXIO;
1564                 goto error;
1565         }
1566
1567         if ((retval = init_nandsim(nsmtd)) != 0) {
1568                 NS_ERR("scan_bbt: can't initialize the nandsim structure\n");
1569                 goto error;
1570         }
1571
1572         if ((retval = nand_default_bbt(nsmtd)) != 0) {
1573                 free_nandsim(nand);
1574                 goto error;
1575         }
1576
1577         /* Register NAND as one big partition */
1578         add_mtd_partitions(nsmtd, &nand->part, 1);
1579
1580         return 0;
1581
1582 error:
1583         kfree(nsmtd);
1584
1585         return retval;
1586 }
1587
1588 module_init(ns_init_module);
1589
1590 /*
1591  * Module clean-up function
1592  */
1593 static void __exit ns_cleanup_module(void)
1594 {
1595         struct nandsim *ns = (struct nandsim *)(((struct nand_chip *)nsmtd->priv)->priv);
1596
1597         free_nandsim(ns);    /* Free nandsim private resources */
1598         nand_release(nsmtd); /* Unregisterd drived */
1599         kfree(nsmtd);        /* Free other structures */
1600 }
1601
1602 module_exit(ns_cleanup_module);
1603
1604 MODULE_LICENSE ("GPL");
1605 MODULE_AUTHOR ("Artem B. Bityuckiy");
1606 MODULE_DESCRIPTION ("The NAND flash simulator");
1607