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