board/pcs440ep/flash.c

   1 /*
   2  * (C) Copyright 2006
   3  * Stefan Roese, DENX Software Engineering, sr@denx.de.
   4  *
   5  * See file CREDITS for list of people who contributed to this
   6  * project.
   7  *
   8  * This program is free software; you can redistribute it and/or
   9  * modify it under the terms of the GNU General Public License as
  10  * published by the Free Software Foundation; either version 2 of
  11  * the License, or (at your option) any later version.
  12  *
  13  * This program is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16  * GNU General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU General Public License
  19  * along with this program; if not, write to the Free Software
  20  * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
  21  * MA 02111-1307 USA
  22  */
  23
  24 #include <common.h>
  25 #include <asm/processor.h>
  26
  27 #ifndef CFG_FLASH_READ0
  28 #define CFG_FLASH_READ0         0x0000  /* 0 is standard                        */
  29 #define CFG_FLASH_READ1         0x0001  /* 1 is standard                        */
  30 #define CFG_FLASH_READ2         0x0002  /* 2 is standard                        */
  31 #endif
  32
  33 flash_info_t    flash_info[CFG_MAX_FLASH_BANKS]; /* info for FLASH chips        */
  34
  35 /*
  36  * Functions
  37  */
  38 static int write_word(flash_info_t *info, ulong dest, ulong data);
  39 static ulong flash_get_size(vu_long *addr, flash_info_t *info);
  40
  41 unsigned long flash_init(void)
  42 {
  43         unsigned long size_b0, size_b1;
  44         int i;
  45         unsigned long base_b0, base_b1;
  46
  47         /* Init: no FLASHes known */
  48         for (i = 0; i < CFG_MAX_FLASH_BANKS; ++i) {
  49                 flash_info[i].flash_id = FLASH_UNKNOWN;
  50         }
  51
  52         /* Static FLASH Bank configuration here - FIXME XXX */
  53
  54         base_b0 = FLASH_BASE0_PRELIM;
  55         size_b0 = flash_get_size ((vu_long *) base_b0, &flash_info[0]);
  56
  57         if (flash_info[0].flash_id == FLASH_UNKNOWN) {
  58                 printf ("## Unknown FLASH on Bank 0 - Size = 0x%08lx = %ld MB\n",
  59                                 size_b0, size_b0 << 20);
  60         }
  61
  62         base_b1 = FLASH_BASE1_PRELIM;
  63         size_b1 = flash_get_size ((vu_long *) base_b1, &flash_info[1]);
  64
  65         return (size_b0 + size_b1);
  66 }
  67
  68 void flash_print_info(flash_info_t *info)
  69 {
  70         int i;
  71         int k;
  72         int size;
  73         int erased;
  74         volatile unsigned long *flash;
  75
  76         if (info->flash_id == FLASH_UNKNOWN) {
  77                 printf ("missing or unknown FLASH type\n");
  78                 return;
  79         }
  80
  81         switch (info->flash_id & FLASH_VENDMASK) {
  82         case FLASH_MAN_AMD:     printf ("AMD ");                break;
  83         case FLASH_MAN_FUJ:     printf ("FUJITSU ");            break;
  84         case FLASH_MAN_SST:     printf ("SST ");                break;
  85         case FLASH_MAN_EXCEL:   printf ("Excel Semiconductor "); break;
  86         case FLASH_MAN_MX:      printf ("MXIC "); break;
  87         default:                printf ("Unknown Vendor ");     break;
  88         }
  89
  90         switch (info->flash_id & FLASH_TYPEMASK) {
  91         case FLASH_AM400B:      printf ("AM29LV400B (4 Mbit, bottom boot sect)\n");
  92                 break;
  93         case FLASH_AM400T:      printf ("AM29LV400T (4 Mbit, top boot sector)\n");
  94                 break;
  95         case FLASH_AM040:       printf ("AM29LV040B (4 Mbit, uniform sector size)\n");
  96                 break;
  97         case FLASH_AM800B:      printf ("AM29LV800B (8 Mbit, bottom boot sect)\n");
  98                 break;
  99         case FLASH_AM800T:      printf ("AM29LV800T (8 Mbit, top boot sector)\n");
 100                 break;
 101         case FLASH_AM160B:      printf ("AM29LV160B (16 Mbit, bottom boot sect)\n");
 102                 break;
 103         case FLASH_AM160T:      printf ("AM29LV160T (16 Mbit, top boot sector)\n");
 104                 break;
 105         case FLASH_AM320T:      printf ("AM29LV320T (32 M, top sector)\n");
 106                 break;
 107         case FLASH_AM320B:      printf ("AM29LV320B (32 M, bottom sector)\n");
 108                 break;
 109         case FLASH_AMDL322T:    printf ("AM29DL322T (32 M, top sector)\n");
 110                 break;
 111         case FLASH_AMDL322B:    printf ("AM29DL322B (32 M, bottom sector)\n");
 112                 break;
 113         case FLASH_AMDL323T:    printf ("AM29DL323T (32 M, top sector)\n");
 114                 break;
 115         case FLASH_AMDL323B:    printf ("AM29DL323B (32 M, bottom sector)\n");
 116                 break;
 117         case FLASH_SST020:      printf ("SST39LF/VF020 (2 Mbit, uniform sector size)\n");
 118                 break;
 119         case FLASH_SST040:      printf ("SST39LF/VF040 (4 Mbit, uniform sector size)\n");
 120                 break;
 121         default:                printf ("Unknown Chip Type\n");
 122                 break;
 123         }
 124
 125         printf ("  Size: %ld MB in %d Sectors\n",
 126                 info->size >> 20, info->sector_count);
 127
 128         printf ("  Sector Start Addresses:");
 129         for (i=0; i<info->sector_count; ++i) {
 130 #ifdef CFG_FLASH_EMPTY_INFO
 131                 /*
 132                  * Check if whole sector is erased
 133                  */
 134                 if (i != (info->sector_count-1))
 135                         size = info->start[i+1] - info->start[i];
 136                 else
 137                         size = info->start[0] + info->size - info->start[i];
 138                 erased = 1;
 139                 flash = (volatile unsigned long *)info->start[i];
 140                 size = size >> 2;       /* divide by 4 for longword access */
 141                 for (k=0; k<size; k++) {
 142                         if (*flash++ != 0xffffffff) {
 143                                 erased = 0;
 144                                 break;
 145                         }
 146                 }
 147
 148                 if ((i % 5) == 0)
 149                         printf ("\n   ");
 150                 /* print empty and read-only info */
 151                 printf (" %08lX%s%s",
 152                         info->start[i],
 153                         erased ? " E" : "  ",
 154                         info->protect[i] ? "RO " : "   ");
 155 #else
 156                 if ((i % 5) == 0)
 157                         printf ("\n   ");
 158                 printf (" %08lX%s",
 159                         info->start[i],
 160                         info->protect[i] ? " (RO)" : "     ");
 161 #endif
 162
 163         }
 164         printf ("\n");
 165         return;
 166 }
 167
 168 /*
 169  * The following code cannot be run from FLASH!
 170  */
 171 static ulong flash_get_size(vu_long *addr, flash_info_t *info)
 172 {
 173         short i;
 174         short n;
 175         volatile CFG_FLASH_WORD_SIZE value;
 176         ulong base = (ulong)addr;
 177         volatile CFG_FLASH_WORD_SIZE *addr2 = (volatile CFG_FLASH_WORD_SIZE *)addr;
 178
 179         /* Write auto select command: read Manufacturer ID */
 180         addr2[CFG_FLASH_ADDR0] = (CFG_FLASH_WORD_SIZE)0x00AA00AA;
 181         addr2[CFG_FLASH_ADDR1] = (CFG_FLASH_WORD_SIZE)0x00550055;
 182         addr2[CFG_FLASH_ADDR0] = (CFG_FLASH_WORD_SIZE)0x00900090;
 183
 184         value = addr2[CFG_FLASH_READ0];
 185
 186         switch (value) {
 187         case (CFG_FLASH_WORD_SIZE)AMD_MANUFACT:
 188                 info->flash_id = FLASH_MAN_AMD;
 189                 break;
 190         case (CFG_FLASH_WORD_SIZE)FUJ_MANUFACT:
 191                 info->flash_id = FLASH_MAN_FUJ;
 192                 break;
 193         case (CFG_FLASH_WORD_SIZE)SST_MANUFACT:
 194                 info->flash_id = FLASH_MAN_SST;
 195                 break;
 196         case (CFG_FLASH_WORD_SIZE)EXCEL_MANUFACT:
 197                 info->flash_id = FLASH_MAN_EXCEL;
 198                 break;
 199         case (CFG_FLASH_WORD_SIZE)MX_MANUFACT:
 200                 info->flash_id = FLASH_MAN_MX;
 201                 break;
 202         default:
 203                 info->flash_id = FLASH_UNKNOWN;
 204                 info->sector_count = 0;
 205                 info->size = 0;
 206                 return (0);                     /* no or unknown flash  */
 207         }
 208
 209         value = addr2[CFG_FLASH_READ1];         /* device ID    */
 210
 211         switch (value) {
 212         case (CFG_FLASH_WORD_SIZE)AMD_ID_LV400T:
 213                 info->flash_id += FLASH_AM400T;
 214                 info->sector_count = 11;
 215                 info->size = 0x00080000;
 216                 break;                          /* => 0.5 MB    */
 217
 218         case (CFG_FLASH_WORD_SIZE)AMD_ID_LV400B:
 219                 info->flash_id += FLASH_AM400B;
 220                 info->sector_count = 11;
 221                 info->size = 0x00080000;
 222                 break;                          /* => 0.5 MB    */
 223
 224         case (CFG_FLASH_WORD_SIZE)AMD_ID_LV040B:
 225                 info->flash_id += FLASH_AM040;
 226                 info->sector_count = 8;
 227                 info->size = 0x0080000;         /* => 0.5 MB    */
 228                 break;
 229
 230         case (CFG_FLASH_WORD_SIZE)AMD_ID_LV800T:
 231                 info->flash_id += FLASH_AM800T;
 232                 info->sector_count = 19;
 233                 info->size = 0x00100000;
 234                 break;                          /* => 1 MB      */
 235
 236         case (CFG_FLASH_WORD_SIZE)AMD_ID_LV800B:
 237                 info->flash_id += FLASH_AM800B;
 238                 info->sector_count = 19;
 239                 info->size = 0x00100000;
 240                 break;                          /* => 1 MB      */
 241
 242         case (CFG_FLASH_WORD_SIZE)AMD_ID_LV160T:
 243                 info->flash_id += FLASH_AM160T;
 244                 info->sector_count = 35;
 245                 info->size = 0x00200000;
 246                 break;                          /* => 2 MB      */
 247
 248         case (CFG_FLASH_WORD_SIZE)AMD_ID_LV160B:
 249                 info->flash_id += FLASH_AM160B;
 250                 info->sector_count = 35;
 251                 info->size = 0x00200000;
 252                 break;                          /* => 2 MB      */
 253
 254         case (CFG_FLASH_WORD_SIZE)AMD_ID_LV320T:
 255                 info->flash_id += FLASH_AM320T;
 256                 info->sector_count = 71;
 257                 info->size = 0x00400000;
 258                 break;                          /* => 4 MB      */
 259
 260         case (CFG_FLASH_WORD_SIZE)AMD_ID_LV320B:
 261                 info->flash_id += FLASH_AM320B;
 262                 info->sector_count = 71;
 263                 info->size = 0x00400000;
 264                 break;                          /* => 4 MB      */
 265
 266         case (CFG_FLASH_WORD_SIZE)AMD_ID_DL322T:
 267                 info->flash_id += FLASH_AMDL322T;
 268                 info->sector_count = 71;
 269                 info->size = 0x00400000;
 270                 break;                          /* => 4 MB      */
 271
 272         case (CFG_FLASH_WORD_SIZE)AMD_ID_DL322B:
 273                 info->flash_id += FLASH_AMDL322B;
 274                 info->sector_count = 71;
 275                 info->size = 0x00400000;
 276                 break;                          /* => 4 MB      */
 277
 278         case (CFG_FLASH_WORD_SIZE)AMD_ID_DL323T:
 279                 info->flash_id += FLASH_AMDL323T;
 280                 info->sector_count = 71;
 281                 info->size = 0x00400000;
 282                 break;                          /* => 4 MB      */
 283
 284         case (CFG_FLASH_WORD_SIZE)AMD_ID_DL323B:
 285                 info->flash_id += FLASH_AMDL323B;
 286                 info->sector_count = 71;
 287                 info->size = 0x00400000;
 288                 break;                          /* => 4 MB      */
 289
 290         case (CFG_FLASH_WORD_SIZE)SST_ID_xF020:
 291                 info->flash_id += FLASH_SST020;
 292                 info->sector_count = 64;
 293                 info->size = 0x00040000;
 294                 break;                          /* => 256 kB    */
 295
 296         case (CFG_FLASH_WORD_SIZE)SST_ID_xF040:
 297                 info->flash_id += FLASH_SST040;
 298                 info->sector_count = 128;
 299                 info->size = 0x00080000;
 300                 break;                          /* => 512 kB    */
 301
 302         default:
 303                 info->flash_id = FLASH_UNKNOWN;
 304                 return (0);                     /* => no or unknown flash */
 305
 306         }
 307
 308         /* set up sector start address table */
 309         if (((info->flash_id & FLASH_VENDMASK) == FLASH_MAN_SST) ||
 310             ((info->flash_id & FLASH_TYPEMASK) == FLASH_AM640U)) {
 311                 for (i = 0; i < info->sector_count; i++)
 312                         info->start[i] = base + (i * 0x00001000);
 313         } else if ((info->flash_id & FLASH_TYPEMASK) == FLASH_AM040) {
 314                 for (i = 0; i < info->sector_count; i++)
 315                         info->start[i] = base + (i * 0x00010000);
 316         } else if (((info->flash_id & FLASH_TYPEMASK) == FLASH_AMDL322B) ||
 317                    ((info->flash_id & FLASH_TYPEMASK) == FLASH_AMDL323B) ||
 318                    ((info->flash_id & FLASH_TYPEMASK) == FLASH_AM320B) ||
 319                    ((info->flash_id & FLASH_TYPEMASK) == FLASH_AMDL324B)) {
 320                 /* set sector offsets for bottom boot block type        */
 321                 for (i=0; i<8; ++i) {           /*  8 x 8k boot sectors */
 322                         info->start[i] = base;
 323                         base += 8 << 10;
 324                 }
 325                 while (i < info->sector_count) {        /* 64k regular sectors  */
 326                         info->start[i] = base;
 327                         base += 64 << 10;
 328                         ++i;
 329                 }
 330         } else if (((info->flash_id & FLASH_TYPEMASK) == FLASH_AMDL322T) ||
 331                    ((info->flash_id & FLASH_TYPEMASK) == FLASH_AMDL323T) ||
 332                    ((info->flash_id & FLASH_TYPEMASK) == FLASH_AM320T) ||
 333                    ((info->flash_id & FLASH_TYPEMASK) == FLASH_AMDL324T)) {
 334                 /* set sector offsets for top boot block type           */
 335                 base += info->size;
 336                 i = info->sector_count;
 337                 for (n=0; n<8; ++n) {           /*  8 x 8k boot sectors */
 338                         base -= 8 << 10;
 339                         --i;
 340                         info->start[i] = base;
 341                 }
 342                 while (i > 0) {                 /* 64k regular sectors  */
 343                         base -= 64 << 10;
 344                         --i;
 345                         info->start[i] = base;
 346                 }
 347         } else {
 348                 if (info->flash_id & FLASH_BTYPE) {
 349                         /* set sector offsets for bottom boot block type        */
 350                         info->start[0] = base + 0x00000000;
 351                         info->start[1] = base + 0x00004000;
 352                         info->start[2] = base + 0x00006000;
 353                         info->start[3] = base + 0x00008000;
 354                         for (i = 4; i < info->sector_count; i++) {
 355                                 info->start[i] = base + (i * 0x00010000) - 0x00030000;
 356                         }
 357                 } else {
 358                         /* set sector offsets for top boot block type           */
 359                         i = info->sector_count - 1;
 360                         info->start[i--] = base + info->size - 0x00004000;
 361                         info->start[i--] = base + info->size - 0x00006000;
 362                         info->start[i--] = base + info->size - 0x00008000;
 363                         for (; i >= 0; i--) {
 364                                 info->start[i] = base + i * 0x00010000;
 365                         }
 366                 }
 367         }
 368
 369         /* check for protected sectors */
 370         for (i = 0; i < info->sector_count; i++) {
 371                 /* read sector protection at sector address, (A7 .. A0) = 0x02 */
 372                 /* D0 = 1 if protected */
 373                 addr2 = (volatile CFG_FLASH_WORD_SIZE *)(info->start[i]);
 374                 if ((info->flash_id & FLASH_VENDMASK) != FLASH_MAN_AMD)
 375                         info->protect[i] = 0;
 376                 else
 377                         info->protect[i] = addr2[CFG_FLASH_READ2] & 1;
 378         }
 379
 380         /*
 381          * Prevent writes to uninitialized FLASH.
 382          */
 383         if (info->flash_id != FLASH_UNKNOWN) {
 384                 addr2 = (CFG_FLASH_WORD_SIZE *)info->start[0];
 385                 *addr2 = (CFG_FLASH_WORD_SIZE)0x00F000F0;       /* reset bank */
 386         }
 387
 388         return (info->size);
 389 }
 390
 391
 392 int flash_erase(flash_info_t *info, int s_first, int s_last)
 393 {
 394         volatile CFG_FLASH_WORD_SIZE *addr = (CFG_FLASH_WORD_SIZE *)(info->start[0]);
 395         volatile CFG_FLASH_WORD_SIZE *addr2;
 396         int flag, prot, sect, l_sect;
 397         ulong start, now, last;
 398
 399         if ((s_first < 0) || (s_first > s_last)) {
 400                 if (info->flash_id == FLASH_UNKNOWN)
 401                         printf ("- missing\n");
 402                 else
 403                         printf ("- no sectors to erase\n");
 404                 return 1;
 405         }
 406
 407         if (info->flash_id == FLASH_UNKNOWN) {
 408                 printf ("Can't erase unknown flash type - aborted\n");
 409                 return 1;
 410         }
 411
 412         prot = 0;
 413         for (sect=s_first; sect<=s_last; ++sect)
 414                 if (info->protect[sect])
 415                         prot++;
 416
 417         if (prot)
 418                 printf ("- Warning: %d protected sectors will not be erased!\n", prot);
 419         else
 420                 printf ("\n");
 421
 422         l_sect = -1;
 423
 424         /* Disable interrupts which might cause a timeout here */
 425         flag = disable_interrupts();
 426
 427         /* Start erase on unprotected sectors */
 428         for (sect = s_first; sect<=s_last; sect++) {
 429                 if (info->protect[sect] == 0) { /* not protected */
 430                         addr2 = (CFG_FLASH_WORD_SIZE *)(info->start[sect]);
 431                         if ((info->flash_id & FLASH_VENDMASK) == FLASH_MAN_SST) {
 432                                 addr[CFG_FLASH_ADDR0] = (CFG_FLASH_WORD_SIZE)0x00AA00AA;
 433                                 addr[CFG_FLASH_ADDR1] = (CFG_FLASH_WORD_SIZE)0x00550055;
 434                                 addr[CFG_FLASH_ADDR0] = (CFG_FLASH_WORD_SIZE)0x00800080;
 435                                 addr[CFG_FLASH_ADDR0] = (CFG_FLASH_WORD_SIZE)0x00AA00AA;
 436                                 addr[CFG_FLASH_ADDR1] = (CFG_FLASH_WORD_SIZE)0x00550055;
 437                                 addr2[0] = (CFG_FLASH_WORD_SIZE)0x00300030;  /* sector erase */
 438
 439                                 /* re-enable interrupts if necessary */
 440                                 if (flag) {
 441                                         enable_interrupts();
 442                                         flag = 0;
 443                                 }
 444
 445                                 /* data polling for D7 */
 446                                 start = get_timer (0);
 447                                 while ((addr2[0] & (CFG_FLASH_WORD_SIZE)0x00800080) !=
 448                                        (CFG_FLASH_WORD_SIZE)0x00800080) {
 449                                         if (get_timer(start) > CFG_FLASH_WRITE_TOUT)
 450                                                 return (1);
 451                                 }
 452                         } else {
 453                                 if (sect == s_first) {
 454                                         addr[CFG_FLASH_ADDR0] = (CFG_FLASH_WORD_SIZE)0x00AA00AA;
 455                                         addr[CFG_FLASH_ADDR1] = (CFG_FLASH_WORD_SIZE)0x00550055;
 456                                         addr[CFG_FLASH_ADDR0] = (CFG_FLASH_WORD_SIZE)0x00800080;
 457                                         addr[CFG_FLASH_ADDR0] = (CFG_FLASH_WORD_SIZE)0x00AA00AA;
 458                                         addr[CFG_FLASH_ADDR1] = (CFG_FLASH_WORD_SIZE)0x00550055;
 459                                 }
 460                                 addr2[0] = (CFG_FLASH_WORD_SIZE)0x00300030;  /* sector erase */
 461                         }
 462                         l_sect = sect;
 463                 }
 464         }
 465
 466         /* re-enable interrupts if necessary */
 467         if (flag)
 468                 enable_interrupts();
 469
 470         /* wait at least 80us - let's wait 1 ms */
 471         udelay (1000);
 472
 473         /*
 474          * We wait for the last triggered sector
 475          */
 476         if (l_sect < 0)
 477                 goto DONE;
 478
 479         start = get_timer (0);
 480         last  = start;
 481         addr = (CFG_FLASH_WORD_SIZE *)(info->start[l_sect]);
 482         while ((addr[0] & (CFG_FLASH_WORD_SIZE)0x00800080) != (CFG_FLASH_WORD_SIZE)0x00800080) {
 483                 if ((now = get_timer(start)) > CFG_FLASH_ERASE_TOUT) {
 484                         printf ("Timeout\n");
 485                         return 1;
 486                 }
 487                 /* show that we're waiting */
 488                 if ((now - last) > 1000) {      /* every second */
 489                         putc ('.');
 490                         last = now;
 491                 }
 492         }
 493
 494 DONE:
 495         /* reset to read mode */
 496         addr = (CFG_FLASH_WORD_SIZE *)info->start[0];
 497         addr[0] = (CFG_FLASH_WORD_SIZE)0x00F000F0;      /* reset bank */
 498
 499         printf (" done\n");
 500         return 0;
 501 }
 502
 503 /*
 504  * Copy memory to flash, returns:
 505  * 0 - OK
 506  * 1 - write timeout
 507  * 2 - Flash not erased
 508  */
 509 int write_buff(flash_info_t *info, uchar *src, ulong addr, ulong cnt)
 510 {
 511         ulong cp, wp, data;
 512         int i, l, rc;
 513
 514         wp = (addr & ~3);       /* get lower word aligned address */
 515
 516         /*
 517          * handle unaligned start bytes
 518          */
 519         if ((l = addr - wp) != 0) {
 520                 data = 0;
 521                 for (i=0, cp=wp; i<l; ++i, ++cp) {
 522                         data = (data << 8) | (*(uchar *)cp);
 523                 }
 524                 for (; i<4 && cnt>0; ++i) {
 525                         data = (data << 8) | *src++;
 526                         --cnt;
 527                         ++cp;
 528                 }
 529                 for (; cnt==0 && i<4; ++i, ++cp) {
 530                         data = (data << 8) | (*(uchar *)cp);
 531                 }
 532
 533                 if ((rc = write_word(info, wp, data)) != 0) {
 534                         return (rc);
 535                 }
 536                 wp += 4;
 537         }
 538
 539         /*
 540          * handle word aligned part
 541          */
 542         while (cnt >= 4) {
 543                 data = 0;
 544                 for (i=0; i<4; ++i)
 545                         data = (data << 8) | *src++;
 546                 if ((rc = write_word(info, wp, data)) != 0)
 547                         return (rc);
 548                 wp  += 4;
 549                 cnt -= 4;
 550         }
 551
 552         if (cnt == 0)
 553                 return (0);
 554
 555         /*
 556          * handle unaligned tail bytes
 557          */
 558         data = 0;
 559         for (i=0, cp=wp; i<4 && cnt>0; ++i, ++cp) {
 560                 data = (data << 8) | *src++;
 561                 --cnt;
 562         }
 563         for (; i<4; ++i, ++cp)
 564                 data = (data << 8) | (*(uchar *)cp);
 565
 566         return (write_word(info, wp, data));
 567 }
 568
 569 /*
 570  * Write a word to Flash, returns:
 571  * 0 - OK
 572  * 1 - write timeout
 573  * 2 - Flash not erased
 574  */
 575 static int write_word(flash_info_t *info, ulong dest, ulong data)
 576 {
 577         volatile CFG_FLASH_WORD_SIZE *addr2 = (CFG_FLASH_WORD_SIZE *)(info->start[0]);
 578         volatile CFG_FLASH_WORD_SIZE *dest2 = (CFG_FLASH_WORD_SIZE *)dest;
 579         volatile CFG_FLASH_WORD_SIZE *data2 = (CFG_FLASH_WORD_SIZE *)&data;
 580         ulong start;
 581         int flag;
 582         int i;
 583
 584         /* Check if Flash is (sufficiently) erased */
 585         if ((*((vu_long *)dest) & data) != data)
 586                 return (2);
 587
 588         /* Disable interrupts which might cause a timeout here */
 589         flag = disable_interrupts();
 590
 591         for (i=0; i<4/sizeof(CFG_FLASH_WORD_SIZE); i++) {
 592                 addr2[CFG_FLASH_ADDR0] = (CFG_FLASH_WORD_SIZE)0x00AA00AA;
 593                 addr2[CFG_FLASH_ADDR1] = (CFG_FLASH_WORD_SIZE)0x00550055;
 594                 addr2[CFG_FLASH_ADDR0] = (CFG_FLASH_WORD_SIZE)0x00A000A0;
 595
 596                 dest2[i] = data2[i];
 597
 598                 /* re-enable interrupts if necessary */
 599                 if (flag)
 600                         enable_interrupts();
 601
 602                 /* data polling for D7 */
 603                 start = get_timer (0);
 604                 while ((dest2[i] & (CFG_FLASH_WORD_SIZE)0x00800080) !=
 605                        (data2[i] & (CFG_FLASH_WORD_SIZE)0x00800080)) {
 606                         if (get_timer(start) > CFG_FLASH_WRITE_TOUT)
 607                                 return (1);
 608                 }
 609         }
 610
 611         return (0);
 612 }