drivers/char/nwflash.c

   1 /*
   2  * Flash memory interface rev.5 driver for the Intel
   3  * Flash chips used on the NetWinder.
   4  *
   5  * 20/08/2000   RMK     use __ioremap to map flash into virtual memory
   6  *                      make a few more places use "volatile"
   7  * 22/05/2001   RMK     - Lock read against write
   8  *                      - merge printk level changes (with mods) from Alan Cox.
   9  *                      - use *ppos as the file position, not file->f_pos.
  10  *                      - fix check for out of range pos and r/w size
  11  *
  12  * Please note that we are tampering with the only flash chip in the
  13  * machine, which contains the bootup code.  We therefore have the
  14  * power to convert these machines into doorstops...
  15  */
  16
  17 #include <linux/module.h>
  18 #include <linux/types.h>
  19 #include <linux/fs.h>
  20 #include <linux/errno.h>
  21 #include <linux/mm.h>
  22 #include <linux/delay.h>
  23 #include <linux/proc_fs.h>
  24 #include <linux/miscdevice.h>
  25 #include <linux/spinlock.h>
  26 #include <linux/rwsem.h>
  27 #include <linux/init.h>
  28 #include <linux/smp_lock.h>
  29 #include <linux/mutex.h>
  30
  31 #include <asm/hardware/dec21285.h>
  32 #include <asm/io.h>
  33 #include <asm/leds.h>
  34 #include <asm/mach-types.h>
  35 #include <asm/system.h>
  36 #include <asm/uaccess.h>
  37
  38 /*****************************************************************************/
  39 #include <asm/nwflash.h>
  40
  41 #define NWFLASH_VERSION "6.4"
  42
  43 static void kick_open(void);
  44 static int get_flash_id(void);
  45 static int erase_block(int nBlock);
  46 static int write_block(unsigned long p, const char __user *buf, int count);
  47
  48 #define KFLASH_SIZE     1024*1024       //1 Meg
  49 #define KFLASH_SIZE4    4*1024*1024     //4 Meg
  50 #define KFLASH_ID       0x89A6          //Intel flash
  51 #define KFLASH_ID4      0xB0D4          //Intel flash 4Meg
  52
  53 static int flashdebug;          //if set - we will display progress msgs
  54
  55 static int gbWriteEnable;
  56 static int gbWriteBase64Enable;
  57 static volatile unsigned char *FLASH_BASE;
  58 static int gbFlashSize = KFLASH_SIZE;
  59 static DEFINE_MUTEX(nwflash_mutex);
  60
  61 extern spinlock_t gpio_lock;
  62
  63 static int get_flash_id(void)
  64 {
  65         volatile unsigned int c1, c2;
  66
  67         /*
  68          * try to get flash chip ID
  69          */
  70         kick_open();
  71         c2 = inb(0x80);
  72         *(volatile unsigned char *) (FLASH_BASE + 0x8000) = 0x90;
  73         udelay(15);
  74         c1 = *(volatile unsigned char *) FLASH_BASE;
  75         c2 = inb(0x80);
  76
  77         /*
  78          * on 4 Meg flash the second byte is actually at offset 2...
  79          */
  80         if (c1 == 0xB0)
  81                 c2 = *(volatile unsigned char *) (FLASH_BASE + 2);
  82         else
  83                 c2 = *(volatile unsigned char *) (FLASH_BASE + 1);
  84
  85         c2 += (c1 << 8);
  86
  87         /*
  88          * set it back to read mode
  89          */
  90         *(volatile unsigned char *) (FLASH_BASE + 0x8000) = 0xFF;
  91
  92         if (c2 == KFLASH_ID4)
  93                 gbFlashSize = KFLASH_SIZE4;
  94
  95         return c2;
  96 }
  97
  98 static int flash_ioctl(struct inode *inodep, struct file *filep, unsigned int cmd, unsigned long arg)
  99 {
 100         switch (cmd) {
 101         case CMD_WRITE_DISABLE:
 102                 gbWriteBase64Enable = 0;
 103                 gbWriteEnable = 0;
 104                 break;
 105
 106         case CMD_WRITE_ENABLE:
 107                 gbWriteEnable = 1;
 108                 break;
 109
 110         case CMD_WRITE_BASE64K_ENABLE:
 111                 gbWriteBase64Enable = 1;
 112                 break;
 113
 114         default:
 115                 gbWriteBase64Enable = 0;
 116                 gbWriteEnable = 0;
 117                 return -EINVAL;
 118         }
 119         return 0;
 120 }
 121
 122 static ssize_t flash_read(struct file *file, char __user *buf, size_t size,
 123                           loff_t *ppos)
 124 {
 125         unsigned long p = *ppos;
 126         unsigned int count = size;
 127         int ret = 0;
 128
 129         if (flashdebug)
 130                 printk(KERN_DEBUG "flash_read: flash_read: offset=0x%lX, "
 131                        "buffer=%p, count=0x%X.\n", p, buf, count);
 132
 133         if (count)
 134                 ret = -ENXIO;
 135
 136         if (p < gbFlashSize) {
 137                 if (count > gbFlashSize - p)
 138                         count = gbFlashSize - p;
 139
 140                 /*
 141                  * We now lock against reads and writes. --rmk
 142                  */
 143                 if (mutex_lock_interruptible(&nwflash_mutex))
 144                         return -ERESTARTSYS;
 145
 146                 ret = copy_to_user(buf, (void *)(FLASH_BASE + p), count);
 147                 if (ret == 0) {
 148                         ret = count;
 149                         *ppos += count;
 150                 } else
 151                         ret = -EFAULT;
 152                 mutex_unlock(&nwflash_mutex);
 153         }
 154         return ret;
 155 }
 156
 157 static ssize_t flash_write(struct file *file, const char __user *buf,
 158                            size_t size, loff_t * ppos)
 159 {
 160         unsigned long p = *ppos;
 161         unsigned int count = size;
 162         int written;
 163         int nBlock, temp, rc;
 164         int i, j;
 165
 166         if (flashdebug)
 167                 printk("flash_write: offset=0x%lX, buffer=0x%p, count=0x%X.\n",
 168                        p, buf, count);
 169
 170         if (!gbWriteEnable)
 171                 return -EINVAL;
 172
 173         if (p < 64 * 1024 && (!gbWriteBase64Enable))
 174                 return -EINVAL;
 175
 176         /*
 177          * check for out of range pos or count
 178          */
 179         if (p >= gbFlashSize)
 180                 return count ? -ENXIO : 0;
 181
 182         if (count > gbFlashSize - p)
 183                 count = gbFlashSize - p;
 184
 185         if (!access_ok(VERIFY_READ, buf, count))
 186                 return -EFAULT;
 187
 188         /*
 189          * We now lock against reads and writes. --rmk
 190          */
 191         if (mutex_lock_interruptible(&nwflash_mutex))
 192                 return -ERESTARTSYS;
 193
 194         written = 0;
 195
 196         leds_event(led_claim);
 197         leds_event(led_green_on);
 198
 199         nBlock = (int) p >> 16; //block # of 64K bytes
 200
 201         /*
 202          * # of 64K blocks to erase and write
 203          */
 204         temp = ((int) (p + count) >> 16) - nBlock + 1;
 205
 206         /*
 207          * write ends at exactly 64k boundary?
 208          */
 209         if (((int) (p + count) & 0xFFFF) == 0)
 210                 temp -= 1;
 211
 212         if (flashdebug)
 213                 printk(KERN_DEBUG "flash_write: writing %d block(s) "
 214                         "starting at %d.\n", temp, nBlock);
 215
 216         for (; temp; temp--, nBlock++) {
 217                 if (flashdebug)
 218                         printk(KERN_DEBUG "flash_write: erasing block %d.\n", nBlock);
 219
 220                 /*
 221                  * first we have to erase the block(s), where we will write...
 222                  */
 223                 i = 0;
 224                 j = 0;
 225           RetryBlock:
 226                 do {
 227                         rc = erase_block(nBlock);
 228                         i++;
 229                 } while (rc && i < 10);
 230
 231                 if (rc) {
 232                         printk(KERN_ERR "flash_write: erase error %x\n", rc);
 233                         break;
 234                 }
 235                 if (flashdebug)
 236                         printk(KERN_DEBUG "flash_write: writing offset %lX, "
 237                                "from buf %p, bytes left %X.\n", p, buf,
 238                                count - written);
 239
 240                 /*
 241                  * write_block will limit write to space left in this block
 242                  */
 243                 rc = write_block(p, buf, count - written);
 244                 j++;
 245
 246                 /*
 247                  * if somehow write verify failed? Can't happen??
 248                  */
 249                 if (!rc) {
 250                         /*
 251                          * retry up to 10 times
 252                          */
 253                         if (j < 10)
 254                                 goto RetryBlock;
 255                         else
 256                                 /*
 257                                  * else quit with error...
 258                                  */
 259                                 rc = -1;
 260
 261                 }
 262                 if (rc < 0) {
 263                         printk(KERN_ERR "flash_write: write error %X\n", rc);
 264                         break;
 265                 }
 266                 p += rc;
 267                 buf += rc;
 268                 written += rc;
 269                 *ppos += rc;
 270
 271                 if (flashdebug)
 272                         printk(KERN_DEBUG "flash_write: written 0x%X bytes OK.\n", written);
 273         }
 274
 275         /*
 276          * restore reg on exit
 277          */
 278         leds_event(led_release);
 279
 280         mutex_unlock(&nwflash_mutex);
 281
 282         return written;
 283 }
 284
 285
 286 /*
 287  * The memory devices use the full 32/64 bits of the offset, and so we cannot
 288  * check against negative addresses: they are ok. The return value is weird,
 289  * though, in that case (0).
 290  *
 291  * also note that seeking relative to the "end of file" isn't supported:
 292  * it has no meaning, so it returns -EINVAL.
 293  */
 294 static loff_t flash_llseek(struct file *file, loff_t offset, int orig)
 295 {
 296         loff_t ret;
 297
 298         lock_kernel();
 299         if (flashdebug)
 300                 printk(KERN_DEBUG "flash_llseek: offset=0x%X, orig=0x%X.\n",
 301                        (unsigned int) offset, orig);
 302
 303         switch (orig) {
 304         case 0:
 305                 if (offset < 0) {
 306                         ret = -EINVAL;
 307                         break;
 308                 }
 309
 310                 if ((unsigned int) offset > gbFlashSize) {
 311                         ret = -EINVAL;
 312                         break;
 313                 }
 314
 315                 file->f_pos = (unsigned int) offset;
 316                 ret = file->f_pos;
 317                 break;
 318         case 1:
 319                 if ((file->f_pos + offset) > gbFlashSize) {
 320                         ret = -EINVAL;
 321                         break;
 322                 }
 323                 if ((file->f_pos + offset) < 0) {
 324                         ret = -EINVAL;
 325                         break;
 326                 }
 327                 file->f_pos += offset;
 328                 ret = file->f_pos;
 329                 break;
 330         default:
 331                 ret = -EINVAL;
 332         }
 333         unlock_kernel();
 334         return ret;
 335 }
 336
 337
 338 /*
 339  * assume that main Write routine did the parameter checking...
 340  * so just go ahead and erase, what requested!
 341  */
 342
 343 static int erase_block(int nBlock)
 344 {
 345         volatile unsigned int c1;
 346         volatile unsigned char *pWritePtr;
 347         unsigned long timeout;
 348         int temp, temp1;
 349
 350         /*
 351          * orange LED == erase
 352          */
 353         leds_event(led_amber_on);
 354
 355         /*
 356          * reset footbridge to the correct offset 0 (...0..3)
 357          */
 358         *CSR_ROMWRITEREG = 0;
 359
 360         /*
 361          * dummy ROM read
 362          */
 363         c1 = *(volatile unsigned char *) (FLASH_BASE + 0x8000);
 364
 365         kick_open();
 366         /*
 367          * reset status if old errors
 368          */
 369         *(volatile unsigned char *) (FLASH_BASE + 0x8000) = 0x50;
 370
 371         /*
 372          * erase a block...
 373          * aim at the middle of a current block...
 374          */
 375         pWritePtr = (unsigned char *) ((unsigned int) (FLASH_BASE + 0x8000 + (nBlock << 16)));
 376         /*
 377          * dummy read
 378          */
 379         c1 = *pWritePtr;
 380
 381         kick_open();
 382         /*
 383          * erase
 384          */
 385         *(volatile unsigned char *) pWritePtr = 0x20;
 386
 387         /*
 388          * confirm
 389          */
 390         *(volatile unsigned char *) pWritePtr = 0xD0;
 391
 392         /*
 393          * wait 10 ms
 394          */
 395         msleep(10);
 396
 397         /*
 398          * wait while erasing in process (up to 10 sec)
 399          */
 400         timeout = jiffies + 10 * HZ;
 401         c1 = 0;
 402         while (!(c1 & 0x80) && time_before(jiffies, timeout)) {
 403                 msleep(10);
 404                 /*
 405                  * read any address
 406                  */
 407                 c1 = *(volatile unsigned char *) (pWritePtr);
 408                 //              printk("Flash_erase: status=%X.\n",c1);
 409         }
 410
 411         /*
 412          * set flash for normal read access
 413          */
 414         kick_open();
 415 //      *(volatile unsigned char*)(FLASH_BASE+0x8000) = 0xFF;
 416         *(volatile unsigned char *) pWritePtr = 0xFF;   //back to normal operation
 417
 418         /*
 419          * check if erase errors were reported
 420          */
 421         if (c1 & 0x20) {
 422                 printk(KERN_ERR "flash_erase: err at %p\n", pWritePtr);
 423
 424                 /*
 425                  * reset error
 426                  */
 427                 *(volatile unsigned char *) (FLASH_BASE + 0x8000) = 0x50;
 428                 return -2;
 429         }
 430
 431         /*
 432          * just to make sure - verify if erased OK...
 433          */
 434         msleep(10);
 435
 436         pWritePtr = (unsigned char *) ((unsigned int) (FLASH_BASE + (nBlock << 16)));
 437
 438         for (temp = 0; temp < 16 * 1024; temp++, pWritePtr += 4) {
 439                 if ((temp1 = *(volatile unsigned int *) pWritePtr) != 0xFFFFFFFF) {
 440                         printk(KERN_ERR "flash_erase: verify err at %p = %X\n",
 441                                pWritePtr, temp1);
 442                         return -1;
 443                 }
 444         }
 445
 446         return 0;
 447
 448 }
 449
 450 /*
 451  * write_block will limit number of bytes written to the space in this block
 452  */
 453 static int write_block(unsigned long p, const char __user *buf, int count)
 454 {
 455         volatile unsigned int c1;
 456         volatile unsigned int c2;
 457         unsigned char *pWritePtr;
 458         unsigned int uAddress;
 459         unsigned int offset;
 460         unsigned long timeout;
 461         unsigned long timeout1;
 462
 463         /*
 464          * red LED == write
 465          */
 466         leds_event(led_amber_off);
 467         leds_event(led_red_on);
 468
 469         pWritePtr = (unsigned char *) ((unsigned int) (FLASH_BASE + p));
 470
 471         /*
 472          * check if write will end in this block....
 473          */
 474         offset = p & 0xFFFF;
 475
 476         if (offset + count > 0x10000)
 477                 count = 0x10000 - offset;
 478
 479         /*
 480          * wait up to 30 sec for this block
 481          */
 482         timeout = jiffies + 30 * HZ;
 483
 484         for (offset = 0; offset < count; offset++, pWritePtr++) {
 485                 uAddress = (unsigned int) pWritePtr;
 486                 uAddress &= 0xFFFFFFFC;
 487                 if (__get_user(c2, buf + offset))
 488                         return -EFAULT;
 489
 490           WriteRetry:
 491                 /*
 492                  * dummy read
 493                  */
 494                 c1 = *(volatile unsigned char *) (FLASH_BASE + 0x8000);
 495
 496                 /*
 497                  * kick open the write gate
 498                  */
 499                 kick_open();
 500
 501                 /*
 502                  * program footbridge to the correct offset...0..3
 503                  */
 504                 *CSR_ROMWRITEREG = (unsigned int) pWritePtr & 3;
 505
 506                 /*
 507                  * write cmd
 508                  */
 509                 *(volatile unsigned char *) (uAddress) = 0x40;
 510
 511                 /*
 512                  * data to write
 513                  */
 514                 *(volatile unsigned char *) (uAddress) = c2;
 515
 516                 /*
 517                  * get status
 518                  */
 519                 *(volatile unsigned char *) (FLASH_BASE + 0x10000) = 0x70;
 520
 521                 c1 = 0;
 522
 523                 /*
 524                  * wait up to 1 sec for this byte
 525                  */
 526                 timeout1 = jiffies + 1 * HZ;
 527
 528                 /*
 529                  * while not ready...
 530                  */
 531                 while (!(c1 & 0x80) && time_before(jiffies, timeout1))
 532                         c1 = *(volatile unsigned char *) (FLASH_BASE + 0x8000);
 533
 534                 /*
 535                  * if timeout getting status
 536                  */
 537                 if (time_after_eq(jiffies, timeout1)) {
 538                         kick_open();
 539                         /*
 540                          * reset err
 541                          */
 542                         *(volatile unsigned char *) (FLASH_BASE + 0x8000) = 0x50;
 543
 544                         goto WriteRetry;
 545                 }
 546                 /*
 547                  * switch on read access, as a default flash operation mode
 548                  */
 549                 kick_open();
 550                 /*
 551                  * read access
 552                  */
 553                 *(volatile unsigned char *) (FLASH_BASE + 0x8000) = 0xFF;
 554
 555                 /*
 556                  * if hardware reports an error writing, and not timeout -
 557                  * reset the chip and retry
 558                  */
 559                 if (c1 & 0x10) {
 560                         kick_open();
 561                         /*
 562                          * reset err
 563                          */
 564                         *(volatile unsigned char *) (FLASH_BASE + 0x8000) = 0x50;
 565
 566                         /*
 567                          * before timeout?
 568                          */
 569                         if (time_before(jiffies, timeout)) {
 570                                 if (flashdebug)
 571                                         printk(KERN_DEBUG "write_block: Retrying write at 0x%X)n",
 572                                                pWritePtr - FLASH_BASE);
 573
 574                                 /*
 575                                  * no LED == waiting
 576                                  */
 577                                 leds_event(led_amber_off);
 578                                 /*
 579                                  * wait couple ms
 580                                  */
 581                                 msleep(10);
 582                                 /*
 583                                  * red LED == write
 584                                  */
 585                                 leds_event(led_red_on);
 586
 587                                 goto WriteRetry;
 588                         } else {
 589                                 printk(KERN_ERR "write_block: timeout at 0x%X\n",
 590                                        pWritePtr - FLASH_BASE);
 591                                 /*
 592                                  * return error -2
 593                                  */
 594                                 return -2;
 595
 596                         }
 597                 }
 598         }
 599
 600         /*
 601          * green LED == read/verify
 602          */
 603         leds_event(led_amber_off);
 604         leds_event(led_green_on);
 605
 606         msleep(10);
 607
 608         pWritePtr = (unsigned char *) ((unsigned int) (FLASH_BASE + p));
 609
 610         for (offset = 0; offset < count; offset++) {
 611                 char c, c1;
 612                 if (__get_user(c, buf))
 613                         return -EFAULT;
 614                 buf++;
 615                 if ((c1 = *pWritePtr++) != c) {
 616                         printk(KERN_ERR "write_block: verify error at 0x%X (%02X!=%02X)\n",
 617                                pWritePtr - FLASH_BASE, c1, c);
 618                         return 0;
 619                 }
 620         }
 621
 622         return count;
 623 }
 624
 625
 626 static void kick_open(void)
 627 {
 628         unsigned long flags;
 629
 630         /*
 631          * we want to write a bit pattern XXX1 to Xilinx to enable
 632          * the write gate, which will be open for about the next 2ms.
 633          */
 634         spin_lock_irqsave(&gpio_lock, flags);
 635         cpld_modify(1, 1);
 636         spin_unlock_irqrestore(&gpio_lock, flags);
 637
 638         /*
 639          * let the ISA bus to catch on...
 640          */
 641         udelay(25);
 642 }
 643
 644 static const struct file_operations flash_fops =
 645 {
 646         .owner          = THIS_MODULE,
 647         .llseek         = flash_llseek,
 648         .read           = flash_read,
 649         .write          = flash_write,
 650         .ioctl          = flash_ioctl,
 651 };
 652
 653 static struct miscdevice flash_miscdev =
 654 {
 655         FLASH_MINOR,
 656         "nwflash",
 657         &flash_fops
 658 };
 659
 660 static int __init nwflash_init(void)
 661 {
 662         int ret = -ENODEV;
 663
 664         if (machine_is_netwinder()) {
 665                 int id;
 666
 667                 FLASH_BASE = ioremap(DC21285_FLASH, KFLASH_SIZE4);
 668                 if (!FLASH_BASE)
 669                         goto out;
 670
 671                 id = get_flash_id();
 672                 if ((id != KFLASH_ID) && (id != KFLASH_ID4)) {
 673                         ret = -ENXIO;
 674                         iounmap((void *)FLASH_BASE);
 675                         printk("Flash: incorrect ID 0x%04X.\n", id);
 676                         goto out;
 677                 }
 678
 679                 printk("Flash ROM driver v.%s, flash device ID 0x%04X, size %d Mb.\n",
 680                        NWFLASH_VERSION, id, gbFlashSize / (1024 * 1024));
 681
 682                 ret = misc_register(&flash_miscdev);
 683                 if (ret < 0) {
 684                         iounmap((void *)FLASH_BASE);
 685                 }
 686         }
 687 out:
 688         return ret;
 689 }
 690
 691 static void __exit nwflash_exit(void)
 692 {
 693         misc_deregister(&flash_miscdev);
 694         iounmap((void *)FLASH_BASE);
 695 }
 696
 697 MODULE_LICENSE("GPL");
 698
 699 module_param(flashdebug, bool, 0644);
 700
 701 module_init(nwflash_init);
 702 module_exit(nwflash_exit);