target/linux/brcm-2.4/files/arch/mips/bcm947xx/nvram_linux.c

   1 /*
   2  * NVRAM variable manipulation (Linux kernel half)
   3  *
   4  * Copyright 2006, Broadcom Corporation
   5  * All Rights Reserved.
   6  *
   7  * THIS SOFTWARE IS OFFERED "AS IS", AND BROADCOM GRANTS NO WARRANTIES OF ANY
   8  * KIND, EXPRESS OR IMPLIED, BY STATUTE, COMMUNICATION OR OTHERWISE. BROADCOM
   9  * SPECIFICALLY DISCLAIMS ANY IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS
  10  * FOR A SPECIFIC PURPOSE OR NONINFRINGEMENT CONCERNING THIS SOFTWARE.
  11  *
  12  * $Id: nvram_linux.c,v 1.19 2006/04/08 07:12:42 honor Exp $
  13  */
  14
  15 #include <linux/config.h>
  16 #include <linux/init.h>
  17 #include <linux/module.h>
  18 #include <linux/kernel.h>
  19 #include <linux/string.h>
  20 #include <linux/interrupt.h>
  21 #include <linux/spinlock.h>
  22 #include <linux/slab.h>
  23 #include <linux/bootmem.h>
  24 #include <linux/wrapper.h>
  25 #include <linux/fs.h>
  26 #include <linux/miscdevice.h>
  27 #include <linux/mtd/mtd.h>
  28 #include <asm/addrspace.h>
  29 #include <asm/io.h>
  30 #include <asm/uaccess.h>
  31
  32 #include <typedefs.h>
  33 #include <osl.h>
  34 #include <bcmendian.h>
  35 #include <bcmnvram.h>
  36 #include <sbconfig.h>
  37 #include <sbchipc.h>
  38 #include <sbutils.h>
  39 #include <hndmips.h>
  40 #include <sflash.h>
  41
  42 /* In BSS to minimize text size and page aligned so it can be mmap()-ed */
  43 static char nvram_buf[NVRAM_SPACE] __attribute__((aligned(PAGE_SIZE)));
  44
  45 #ifdef MODULE
  46
  47 #define early_nvram_get(name) nvram_get(name)
  48
  49 #else /* !MODULE */
  50
  51 /* Global SB handle */
  52 extern void *bcm947xx_sbh;
  53 extern spinlock_t bcm947xx_sbh_lock;
  54
  55 static int cfe_env;
  56 extern char *cfe_env_get(char *nv_buf, const char *name);
  57
  58 /* Convenience */
  59 #define sbh bcm947xx_sbh
  60 #define sbh_lock bcm947xx_sbh_lock
  61 #define KB * 1024
  62 #define MB * 1024 * 1024
  63
  64 /* Probe for NVRAM header */
  65 static void __init
  66 early_nvram_init(void)
  67 {
  68         struct nvram_header *header;
  69         chipcregs_t *cc;
  70         struct sflash *info = NULL;
  71         int i;
  72         uint32 base, off, lim;
  73         u32 *src, *dst;
  74
  75         if ((cc = sb_setcore(sbh, SB_CC, 0)) != NULL) {
  76                 base = KSEG1ADDR(SB_FLASH2);
  77                 switch (readl(&cc->capabilities) & CC_CAP_FLASH_MASK) {
  78                 case PFLASH:
  79                         lim = SB_FLASH2_SZ;
  80                         break;
  81
  82                 case SFLASH_ST:
  83                 case SFLASH_AT:
  84                         if ((info = sflash_init(sbh,cc)) == NULL)
  85                                 return;
  86                         lim = info->size;
  87                         break;
  88
  89                 case FLASH_NONE:
  90                 default:
  91                         return;
  92                 }
  93         } else {
  94                 /* extif assumed, Stop at 4 MB */
  95                 base = KSEG1ADDR(SB_FLASH1);
  96                 lim = SB_FLASH1_SZ;
  97         }
  98
  99         /* XXX: hack for supporting the CFE environment stuff on WGT634U */
 100         src = (u32 *) KSEG1ADDR(base + 8 * 1024 * 1024 - 0x2000);
 101         dst = (u32 *) nvram_buf;
 102         if ((lim == 0x02000000) && ((*src & 0xff00ff) == 0x000001)) {
 103                 printk("early_nvram_init: WGT634U NVRAM found.\n");
 104
 105                 for (i = 0; i < 0x1ff0; i++) {
 106                         if (*src == 0xFFFFFFFF)
 107                                 break;
 108                         *dst++ = *src++;
 109                 }
 110                 cfe_env = 1;
 111                 return;
 112         }
 113
 114         off = FLASH_MIN;
 115         while (off <= lim) {
 116                 /* Windowed flash access */
 117                 header = (struct nvram_header *) KSEG1ADDR(base + off - NVRAM_SPACE);
 118                 if (header->magic == NVRAM_MAGIC)
 119                         goto found;
 120                 off <<= 1;
 121         }
 122
 123         /* Try embedded NVRAM at 4 KB and 1 KB as last resorts */
 124         header = (struct nvram_header *) KSEG1ADDR(base + 4 KB);
 125         if (header->magic == NVRAM_MAGIC)
 126                 goto found;
 127
 128         header = (struct nvram_header *) KSEG1ADDR(base + 1 KB);
 129         if (header->magic == NVRAM_MAGIC)
 130                 goto found;
 131
 132         printk("early_nvram_init: NVRAM not found\n");
 133         return;
 134
 135 found:
 136         src = (u32 *) header;
 137         dst = (u32 *) nvram_buf;
 138         for (i = 0; i < sizeof(struct nvram_header); i += 4)
 139                 *dst++ = *src++;
 140         for (; i < header->len && i < NVRAM_SPACE; i += 4)
 141                 *dst++ = ltoh32(*src++);
 142 }
 143
 144 /* Early (before mm or mtd) read-only access to NVRAM */
 145 static char * __init
 146 early_nvram_get(const char *name)
 147 {
 148         char *var, *value, *end, *eq;
 149
 150         if (!name)
 151                 return NULL;
 152
 153         /* Too early? */
 154         if (sbh == NULL)
 155                 return NULL;
 156
 157         if (!nvram_buf[0])
 158                 early_nvram_init();
 159
 160         if (cfe_env)
 161                 return cfe_env_get(nvram_buf, name);
 162
 163         /* Look for name=value and return value */
 164         var = &nvram_buf[sizeof(struct nvram_header)];
 165         end = nvram_buf + sizeof(nvram_buf) - 2;
 166         end[0] = end[1] = '\0';
 167         for (; *var; var = value + strlen(value) + 1) {
 168                 if (!(eq = strchr(var, '=')))
 169                         break;
 170                 value = eq + 1;
 171                 if ((eq - var) == strlen(name) && strncmp(var, name, (eq - var)) == 0)
 172                         return value;
 173         }
 174
 175         return NULL;
 176 }
 177
 178 static int __init
 179 early_nvram_getall(char *buf, int count)
 180 {
 181         char *var, *end;
 182         int len = 0;
 183
 184         /* Too early? */
 185         if (sbh == NULL)
 186                 return -1;
 187
 188         if (!nvram_buf[0])
 189                 early_nvram_init();
 190
 191         bzero(buf, count);
 192
 193         /* Write name=value\0 ... \0\0 */
 194         var = &nvram_buf[sizeof(struct nvram_header)];
 195         end = nvram_buf + sizeof(nvram_buf) - 2;
 196         end[0] = end[1] = '\0';
 197         for (; *var; var += strlen(var) + 1) {
 198                 if ((count - len) <= (strlen(var) + 1))
 199                         break;
 200                 len += sprintf(buf + len, "%s", var) + 1;
 201         }
 202
 203         return 0;
 204 }
 205 #endif /* !MODULE */
 206
 207 extern char * _nvram_get(const char *name);
 208 extern int _nvram_set(const char *name, const char *value);
 209 extern int _nvram_unset(const char *name);
 210 extern int _nvram_getall(char *buf, int count);
 211 extern int _nvram_commit(struct nvram_header *header);
 212 extern int _nvram_init(void *sbh);
 213 extern void _nvram_exit(void);
 214
 215 /* Globals */
 216 static spinlock_t nvram_lock = SPIN_LOCK_UNLOCKED;
 217 static struct semaphore nvram_sem;
 218 static unsigned long nvram_offset = 0;
 219 static int nvram_major = -1;
 220 static devfs_handle_t nvram_handle = NULL;
 221 static struct mtd_info *nvram_mtd = NULL;
 222
 223 int
 224 _nvram_read(char *buf)
 225 {
 226         struct nvram_header *header = (struct nvram_header *) buf;
 227         size_t len;
 228
 229         if (!nvram_mtd ||
 230             MTD_READ(nvram_mtd, nvram_mtd->size - NVRAM_SPACE, NVRAM_SPACE, &len, buf) ||
 231             len != NVRAM_SPACE ||
 232             header->magic != NVRAM_MAGIC) {
 233                 /* Maybe we can recover some data from early initialization */
 234                 memcpy(buf, nvram_buf, NVRAM_SPACE);
 235         }
 236
 237         return 0;
 238 }
 239
 240 struct nvram_tuple *
 241 _nvram_realloc(struct nvram_tuple *t, const char *name, const char *value)
 242 {
 243         if ((nvram_offset + strlen(value) + 1) > NVRAM_SPACE)
 244                 return NULL;
 245
 246         if (!t) {
 247                 if (!(t = kmalloc(sizeof(struct nvram_tuple) + strlen(name) + 1, GFP_ATOMIC)))
 248                         return NULL;
 249
 250                 /* Copy name */
 251                 t->name = (char *) &t[1];
 252                 strcpy(t->name, name);
 253
 254                 t->value = NULL;
 255         }
 256
 257         /* Copy value */
 258         if (!t->value || strcmp(t->value, value)) {
 259                 t->value = &nvram_buf[nvram_offset];
 260                 strcpy(t->value, value);
 261                 nvram_offset += strlen(value) + 1;
 262         }
 263
 264         return t;
 265 }
 266
 267 void
 268 _nvram_free(struct nvram_tuple *t)
 269 {
 270         if (!t)
 271                 nvram_offset = 0;
 272         else
 273                 kfree(t);
 274 }
 275
 276 int
 277 nvram_set(const char *name, const char *value)
 278 {
 279         unsigned long flags;
 280         int ret;
 281         struct nvram_header *header;
 282
 283         spin_lock_irqsave(&nvram_lock, flags);
 284         if ((ret = _nvram_set(name, value))) {
 285                 /* Consolidate space and try again */
 286                 if ((header = kmalloc(NVRAM_SPACE, GFP_ATOMIC))) {
 287                         if (_nvram_commit(header) == 0)
 288                                 ret = _nvram_set(name, value);
 289                         kfree(header);
 290                 }
 291         }
 292         spin_unlock_irqrestore(&nvram_lock, flags);
 293
 294         return ret;
 295 }
 296
 297 char *
 298 real_nvram_get(const char *name)
 299 {
 300         unsigned long flags;
 301         char *value;
 302
 303         spin_lock_irqsave(&nvram_lock, flags);
 304         value = _nvram_get(name);
 305         spin_unlock_irqrestore(&nvram_lock, flags);
 306
 307         return value;
 308 }
 309
 310 char *
 311 nvram_get(const char *name)
 312 {
 313         if (nvram_major >= 0)
 314                 return real_nvram_get(name);
 315         else
 316                 return early_nvram_get(name);
 317 }
 318
 319 int
 320 nvram_unset(const char *name)
 321 {
 322         unsigned long flags;
 323         int ret;
 324
 325         spin_lock_irqsave(&nvram_lock, flags);
 326         ret = _nvram_unset(name);
 327         spin_unlock_irqrestore(&nvram_lock, flags);
 328
 329         return ret;
 330 }
 331
 332 static void
 333 erase_callback(struct erase_info *done)
 334 {
 335         wait_queue_head_t *wait_q = (wait_queue_head_t *) done->priv;
 336         wake_up(wait_q);
 337 }
 338
 339 int
 340 nvram_commit(void)
 341 {
 342         char *buf;
 343         size_t erasesize, len, magic_len;
 344         unsigned int i;
 345         int ret;
 346         struct nvram_header *header;
 347         unsigned long flags;
 348         u_int32_t offset;
 349         DECLARE_WAITQUEUE(wait, current);
 350         wait_queue_head_t wait_q;
 351         struct erase_info erase;
 352         u_int32_t magic_offset = 0; /* Offset for writing MAGIC # */
 353
 354         if (!nvram_mtd) {
 355                 printk("nvram_commit: NVRAM not found\n");
 356                 return -ENODEV;
 357         }
 358
 359         if (in_interrupt()) {
 360                 printk("nvram_commit: not committing in interrupt\n");
 361                 return -EINVAL;
 362         }
 363
 364         /* Backup sector blocks to be erased */
 365         erasesize = ROUNDUP(NVRAM_SPACE, nvram_mtd->erasesize);
 366         if (!(buf = kmalloc(erasesize, GFP_KERNEL))) {
 367                 printk("nvram_commit: out of memory\n");
 368                 return -ENOMEM;
 369         }
 370
 371         down(&nvram_sem);
 372
 373         if ((i = erasesize - NVRAM_SPACE) > 0) {
 374                 offset = nvram_mtd->size - erasesize;
 375                 len = 0;
 376                 ret = MTD_READ(nvram_mtd, offset, i, &len, buf);
 377                 if (ret || len != i) {
 378                         printk("nvram_commit: read error ret = %d, len = %d/%d\n", ret, len, i);
 379                         ret = -EIO;
 380                         goto done;
 381                 }
 382                 header = (struct nvram_header *)(buf + i);
 383                 magic_offset = i + ((void *)&header->magic - (void *)header);
 384         } else {
 385                 offset = nvram_mtd->size - NVRAM_SPACE;
 386                 magic_offset = ((void *)&header->magic - (void *)header);
 387                 header = (struct nvram_header *)buf;
 388         }
 389
 390         /* clear the existing magic # to mark the NVRAM as unusable
 391                  we can pull MAGIC bits low without erase       */
 392         header->magic = NVRAM_CLEAR_MAGIC; /* All zeros magic */
 393
 394         /* Unlock sector blocks (for Intel 28F320C3B flash) , 20060309 */
 395         if(nvram_mtd->unlock)
 396                 nvram_mtd->unlock(nvram_mtd, offset, nvram_mtd->erasesize);
 397
 398         ret = MTD_WRITE(nvram_mtd, offset + magic_offset, sizeof(header->magic),
 399                                                                         &magic_len, (char *)&header->magic);
 400         if (ret || magic_len != sizeof(header->magic)) {
 401                 printk("nvram_commit: clear MAGIC error\n");
 402                 ret = -EIO;
 403                 goto done;
 404         }
 405
 406         header->magic = NVRAM_MAGIC; /* reset MAGIC before we regenerate the NVRAM,
 407                                                                                                                                 otherwise we'll have an incorrect CRC */
 408         /* Regenerate NVRAM */
 409         spin_lock_irqsave(&nvram_lock, flags);
 410         ret = _nvram_commit(header);
 411         spin_unlock_irqrestore(&nvram_lock, flags);
 412         if (ret)
 413                 goto done;
 414
 415         /* Erase sector blocks */
 416         init_waitqueue_head(&wait_q);
 417         for (; offset < nvram_mtd->size - NVRAM_SPACE + header->len; offset += nvram_mtd->erasesize) {
 418                 erase.mtd = nvram_mtd;
 419                 erase.addr = offset;
 420                 erase.len = nvram_mtd->erasesize;
 421                 erase.callback = erase_callback;
 422                 erase.priv = (u_long) &wait_q;
 423
 424                 set_current_state(TASK_INTERRUPTIBLE);
 425                 add_wait_queue(&wait_q, &wait);
 426
 427                 /* Unlock sector blocks */
 428                 if (nvram_mtd->unlock)
 429                         nvram_mtd->unlock(nvram_mtd, offset, nvram_mtd->erasesize);
 430
 431                 if ((ret = MTD_ERASE(nvram_mtd, &erase))) {
 432                         set_current_state(TASK_RUNNING);
 433                         remove_wait_queue(&wait_q, &wait);
 434                         printk("nvram_commit: erase error\n");
 435                         goto done;
 436                 }
 437
 438                 /* Wait for erase to finish */
 439                 schedule();
 440                 remove_wait_queue(&wait_q, &wait);
 441         }
 442
 443         /* Write partition up to end of data area */
 444         header->magic = NVRAM_INVALID_MAGIC; /* All ones magic */
 445         offset = nvram_mtd->size - erasesize;
 446         i = erasesize - NVRAM_SPACE + header->len;
 447         ret = MTD_WRITE(nvram_mtd, offset, i, &len, buf);
 448         if (ret || len != i) {
 449                 printk("nvram_commit: write error\n");
 450                 ret = -EIO;
 451                 goto done;
 452         }
 453
 454         /* Now mark the NVRAM in flash as "valid" by setting the correct
 455                  MAGIC # */
 456         header->magic = NVRAM_MAGIC;
 457         ret = MTD_WRITE(nvram_mtd, offset + magic_offset, sizeof(header->magic),
 458                                                                         &magic_len, (char *)&header->magic);
 459         if (ret || magic_len != sizeof(header->magic)) {
 460                 printk("nvram_commit: write MAGIC error\n");
 461                 ret = -EIO;
 462                 goto done;
 463         }
 464
 465         /*
 466          * Reading a few bytes back here will put the device
 467          * back to the correct mode on certain flashes */
 468         offset = nvram_mtd->size - erasesize;
 469         ret = MTD_READ(nvram_mtd, offset, 4, &len, buf);
 470
 471  done:
 472         up(&nvram_sem);
 473         kfree(buf);
 474
 475         return ret;
 476 }
 477
 478 int
 479 nvram_getall(char *buf, int count)
 480 {
 481         unsigned long flags;
 482         int ret;
 483
 484         spin_lock_irqsave(&nvram_lock, flags);
 485         if (nvram_major >= 0)
 486                 ret = _nvram_getall(buf, count);
 487         else
 488                 ret = early_nvram_getall(buf, count);
 489         spin_unlock_irqrestore(&nvram_lock, flags);
 490
 491         return ret;
 492 }
 493
 494
 495
 496
 497
 498
 499
 500 /* User mode interface below */
 501
 502 static ssize_t
 503 dev_nvram_read(struct file *file, char *buf, size_t count, loff_t *ppos)
 504 {
 505         char tmp[100], *name = tmp, *value;
 506         ssize_t ret;
 507         unsigned long off;
 508
 509         if (count > sizeof(tmp)) {
 510                 if (!(name = kmalloc(count, GFP_KERNEL)))
 511                         return -ENOMEM;
 512         }
 513
 514         if (copy_from_user(name, buf, count)) {
 515                 ret = -EFAULT;
 516                 goto done;
 517         }
 518
 519         if (*name == '\0') {
 520                 /* Get all variables */
 521                 ret = nvram_getall(name, count);
 522                 if (ret == 0) {
 523                         if (copy_to_user(buf, name, count)) {
 524                                 ret = -EFAULT;
 525                                 goto done;
 526                         }
 527                         ret = count;
 528                 }
 529         } else {
 530                 if (!(value = nvram_get(name))) {
 531                         ret = 0;
 532                         goto done;
 533                 }
 534
 535                 /* Provide the offset into mmap() space */
 536                 off = (unsigned long) value - (unsigned long) nvram_buf;
 537
 538                 if (put_user(off, (unsigned long *) buf)) {
 539                         ret = -EFAULT;
 540                         goto done;
 541                 }
 542
 543                 ret = sizeof(unsigned long);
 544         }
 545
 546         flush_cache_all();
 547
 548 done:
 549         if (name != tmp)
 550                 kfree(name);
 551
 552         return ret;
 553 }
 554
 555 static ssize_t
 556 dev_nvram_write(struct file *file, const char *buf, size_t count, loff_t *ppos)
 557 {
 558         char tmp[100], *name = tmp, *value;
 559         ssize_t ret;
 560
 561         if (count > sizeof(tmp)) {
 562                 if (!(name = kmalloc(count, GFP_KERNEL)))
 563                         return -ENOMEM;
 564         }
 565
 566         if (copy_from_user(name, buf, count)) {
 567                 ret = -EFAULT;
 568                 goto done;
 569         }
 570
 571         value = name;
 572         name = strsep(&value, "=");
 573         if (value)
 574                 ret = nvram_set(name, value) ? : count;
 575         else
 576                 ret = nvram_unset(name) ? : count;
 577
 578  done:
 579         if (name != tmp)
 580                 kfree(name);
 581
 582         return ret;
 583 }
 584
 585 static int
 586 dev_nvram_ioctl(struct inode *inode, struct file *file, unsigned int cmd, unsigned long arg)
 587 {
 588         if (cmd != NVRAM_MAGIC)
 589                 return -EINVAL;
 590
 591         return nvram_commit();
 592 }
 593
 594 static int
 595 dev_nvram_mmap(struct file *file, struct vm_area_struct *vma)
 596 {
 597         unsigned long offset = virt_to_phys(nvram_buf);
 598
 599         if (remap_page_range(vma->vm_start, offset, vma->vm_end-vma->vm_start,
 600                              vma->vm_page_prot))
 601                 return -EAGAIN;
 602
 603         return 0;
 604 }
 605
 606 static int
 607 dev_nvram_open(struct inode *inode, struct file * file)
 608 {
 609         MOD_INC_USE_COUNT;
 610         return 0;
 611 }
 612
 613 static int
 614 dev_nvram_release(struct inode *inode, struct file * file)
 615 {
 616         MOD_DEC_USE_COUNT;
 617         return 0;
 618 }
 619
 620 static struct file_operations dev_nvram_fops = {
 621         owner:          THIS_MODULE,
 622         open:           dev_nvram_open,
 623         release:        dev_nvram_release,
 624         read:           dev_nvram_read,
 625         write:          dev_nvram_write,
 626         ioctl:          dev_nvram_ioctl,
 627         mmap:           dev_nvram_mmap,
 628 };
 629
 630 static void
 631 dev_nvram_exit(void)
 632 {
 633         int order = 0;
 634         struct page *page, *end;
 635
 636         if (nvram_handle)
 637                 devfs_unregister(nvram_handle);
 638
 639         if (nvram_major >= 0)
 640                 devfs_unregister_chrdev(nvram_major, "nvram");
 641
 642         if (nvram_mtd)
 643                 put_mtd_device(nvram_mtd);
 644
 645         while ((PAGE_SIZE << order) < NVRAM_SPACE)
 646                 order++;
 647         end = virt_to_page(nvram_buf + (PAGE_SIZE << order) - 1);
 648         for (page = virt_to_page(nvram_buf); page <= end; page++)
 649                 mem_map_unreserve(page);
 650
 651         _nvram_exit();
 652 }
 653
 654 static int __init
 655 dev_nvram_init(void)
 656 {
 657         int order = 0, ret = 0;
 658         struct page *page, *end;
 659         unsigned int i;
 660
 661         /* Allocate and reserve memory to mmap() */
 662         while ((PAGE_SIZE << order) < NVRAM_SPACE)
 663                 order++;
 664         end = virt_to_page(nvram_buf + (PAGE_SIZE << order) - 1);
 665         for (page = virt_to_page(nvram_buf); page <= end; page++)
 666                 mem_map_reserve(page);
 667
 668 #ifdef CONFIG_MTD
 669         /* Find associated MTD device */
 670         for (i = 0; i < MAX_MTD_DEVICES; i++) {
 671                 nvram_mtd = get_mtd_device(NULL, i);
 672                 if (nvram_mtd) {
 673                         if (!strcmp(nvram_mtd->name, "nvram") &&
 674                             nvram_mtd->size >= NVRAM_SPACE)
 675                                 break;
 676                         put_mtd_device(nvram_mtd);
 677                 }
 678         }
 679         if (i >= MAX_MTD_DEVICES)
 680                 nvram_mtd = NULL;
 681 #endif
 682
 683         /* Initialize hash table lock */
 684         spin_lock_init(&nvram_lock);
 685
 686         /* Initialize commit semaphore */
 687         init_MUTEX(&nvram_sem);
 688
 689         /* Register char device */
 690         if ((nvram_major = devfs_register_chrdev(0, "nvram", &dev_nvram_fops)) < 0) {
 691                 ret = nvram_major;
 692                 goto err;
 693         }
 694
 695         /* Initialize hash table */
 696         _nvram_init(sbh);
 697
 698         /* Create /dev/nvram handle */
 699         nvram_handle = devfs_register(NULL, "nvram", DEVFS_FL_NONE, nvram_major, 0,
 700                                       S_IFCHR | S_IRUSR | S_IWUSR | S_IRGRP, &dev_nvram_fops, NULL);
 701
 702         /* Set the SDRAM NCDL value into NVRAM if not already done */
 703         if (getintvar(NULL, "sdram_ncdl") == 0) {
 704                 unsigned int ncdl;
 705                 char buf[] = "0x00000000";
 706
 707                 if ((ncdl = sb_memc_get_ncdl(sbh))) {
 708                         sprintf(buf, "0x%08x", ncdl);
 709                         nvram_set("sdram_ncdl", buf);
 710                         nvram_commit();
 711                 }
 712         }
 713
 714         return 0;
 715
 716  err:
 717         dev_nvram_exit();
 718         return ret;
 719 }
 720
 721 module_init(dev_nvram_init);
 722 module_exit(dev_nvram_exit);