arch/powerpc/kernel/nvram_64.c

   1 /*
   2  *  c 2001 PPC 64 Team, IBM Corp
   3  *
   4  *      This program is free software; you can redistribute it and/or
   5  *      modify it under the terms of the GNU General Public License
   6  *      as published by the Free Software Foundation; either version
   7  *      2 of the License, or (at your option) any later version.
   8  *
   9  * /dev/nvram driver for PPC64
  10  *
  11  * This perhaps should live in drivers/char
  12  *
  13  * TODO: Split the /dev/nvram part (that one can use
  14  *       drivers/char/generic_nvram.c) from the arch & partition
  15  *       parsing code.
  16  */
  17
  18 #include <linux/module.h>
  19
  20 #include <linux/types.h>
  21 #include <linux/errno.h>
  22 #include <linux/fs.h>
  23 #include <linux/miscdevice.h>
  24 #include <linux/fcntl.h>
  25 #include <linux/nvram.h>
  26 #include <linux/init.h>
  27 #include <linux/slab.h>
  28 #include <linux/spinlock.h>
  29 #include <asm/uaccess.h>
  30 #include <asm/nvram.h>
  31 #include <asm/rtas.h>
  32 #include <asm/prom.h>
  33 #include <asm/machdep.h>
  34
  35 #undef DEBUG_NVRAM
  36
  37 static struct nvram_partition * nvram_part;
  38 static long nvram_error_log_index = -1;
  39 static long nvram_error_log_size = 0;
  40
  41 struct err_log_info {
  42         int error_type;
  43         unsigned int seq_num;
  44 };
  45
  46 static loff_t dev_nvram_llseek(struct file *file, loff_t offset, int origin)
  47 {
  48         int size;
  49
  50         if (ppc_md.nvram_size == NULL)
  51                 return -ENODEV;
  52         size = ppc_md.nvram_size();
  53
  54         switch (origin) {
  55         case 1:
  56                 offset += file->f_pos;
  57                 break;
  58         case 2:
  59                 offset += size;
  60                 break;
  61         }
  62         if (offset < 0)
  63                 return -EINVAL;
  64         file->f_pos = offset;
  65         return file->f_pos;
  66 }
  67
  68
  69 static ssize_t dev_nvram_read(struct file *file, char __user *buf,
  70                           size_t count, loff_t *ppos)
  71 {
  72         ssize_t ret;
  73         char *tmp = NULL;
  74         ssize_t size;
  75
  76         ret = -ENODEV;
  77         if (!ppc_md.nvram_size)
  78                 goto out;
  79
  80         ret = 0;
  81         size = ppc_md.nvram_size();
  82         if (*ppos >= size || size < 0)
  83                 goto out;
  84
  85         count = min_t(size_t, count, size - *ppos);
  86         count = min(count, PAGE_SIZE);
  87
  88         ret = -ENOMEM;
  89         tmp = kmalloc(count, GFP_KERNEL);
  90         if (!tmp)
  91                 goto out;
  92
  93         ret = ppc_md.nvram_read(tmp, count, ppos);
  94         if (ret <= 0)
  95                 goto out;
  96
  97         if (copy_to_user(buf, tmp, ret))
  98                 ret = -EFAULT;
  99
 100 out:
 101         kfree(tmp);
 102         return ret;
 103
 104 }
 105
 106 static ssize_t dev_nvram_write(struct file *file, const char __user *buf,
 107                           size_t count, loff_t *ppos)
 108 {
 109         ssize_t ret;
 110         char *tmp = NULL;
 111         ssize_t size;
 112
 113         ret = -ENODEV;
 114         if (!ppc_md.nvram_size)
 115                 goto out;
 116
 117         ret = 0;
 118         size = ppc_md.nvram_size();
 119         if (*ppos >= size || size < 0)
 120                 goto out;
 121
 122         count = min_t(size_t, count, size - *ppos);
 123         count = min(count, PAGE_SIZE);
 124
 125         ret = -ENOMEM;
 126         tmp = kmalloc(count, GFP_KERNEL);
 127         if (!tmp)
 128                 goto out;
 129
 130         ret = -EFAULT;
 131         if (copy_from_user(tmp, buf, count))
 132                 goto out;
 133
 134         ret = ppc_md.nvram_write(tmp, count, ppos);
 135
 136 out:
 137         kfree(tmp);
 138         return ret;
 139
 140 }
 141
 142 static int dev_nvram_ioctl(struct inode *inode, struct file *file,
 143         unsigned int cmd, unsigned long arg)
 144 {
 145         switch(cmd) {
 146 #ifdef CONFIG_PPC_PMAC
 147         case OBSOLETE_PMAC_NVRAM_GET_OFFSET:
 148                 printk(KERN_WARNING "nvram: Using obsolete PMAC_NVRAM_GET_OFFSET ioctl\n");
 149         case IOC_NVRAM_GET_OFFSET: {
 150                 int part, offset;
 151
 152                 if (!machine_is(powermac))
 153                         return -EINVAL;
 154                 if (copy_from_user(&part, (void __user*)arg, sizeof(part)) != 0)
 155                         return -EFAULT;
 156                 if (part < pmac_nvram_OF || part > pmac_nvram_NR)
 157                         return -EINVAL;
 158                 offset = pmac_get_partition(part);
 159                 if (offset < 0)
 160                         return offset;
 161                 if (copy_to_user((void __user*)arg, &offset, sizeof(offset)) != 0)
 162                         return -EFAULT;
 163                 return 0;
 164         }
 165 #endif /* CONFIG_PPC_PMAC */
 166         default:
 167                 return -EINVAL;
 168         }
 169 }
 170
 171 const struct file_operations nvram_fops = {
 172         .owner =        THIS_MODULE,
 173         .llseek =       dev_nvram_llseek,
 174         .read =         dev_nvram_read,
 175         .write =        dev_nvram_write,
 176         .ioctl =        dev_nvram_ioctl,
 177 };
 178
 179 static struct miscdevice nvram_dev = {
 180         NVRAM_MINOR,
 181         "nvram",
 182         &nvram_fops
 183 };
 184
 185
 186 #ifdef DEBUG_NVRAM
 187 static void nvram_print_partitions(char * label)
 188 {
 189         struct list_head * p;
 190         struct nvram_partition * tmp_part;
 191
 192         printk(KERN_WARNING "--------%s---------\n", label);
 193         printk(KERN_WARNING "indx\t\tsig\tchks\tlen\tname\n");
 194         list_for_each(p, &nvram_part->partition) {
 195                 tmp_part = list_entry(p, struct nvram_partition, partition);
 196                 printk(KERN_WARNING "%4d    \t%02x\t%02x\t%d\t%s\n",
 197                        tmp_part->index, tmp_part->header.signature,
 198                        tmp_part->header.checksum, tmp_part->header.length,
 199                        tmp_part->header.name);
 200         }
 201 }
 202 #endif
 203
 204
 205 static int nvram_write_header(struct nvram_partition * part)
 206 {
 207         loff_t tmp_index;
 208         int rc;
 209
 210         tmp_index = part->index;
 211         rc = ppc_md.nvram_write((char *)&part->header, NVRAM_HEADER_LEN, &tmp_index);
 212
 213         return rc;
 214 }
 215
 216
 217 static unsigned char nvram_checksum(struct nvram_header *p)
 218 {
 219         unsigned int c_sum, c_sum2;
 220         unsigned short *sp = (unsigned short *)p->name; /* assume 6 shorts */
 221         c_sum = p->signature + p->length + sp[0] + sp[1] + sp[2] + sp[3] + sp[4] + sp[5];
 222
 223         /* The sum may have spilled into the 3rd byte.  Fold it back. */
 224         c_sum = ((c_sum & 0xffff) + (c_sum >> 16)) & 0xffff;
 225         /* The sum cannot exceed 2 bytes.  Fold it into a checksum */
 226         c_sum2 = (c_sum >> 8) + (c_sum << 8);
 227         c_sum = ((c_sum + c_sum2) >> 8) & 0xff;
 228         return c_sum;
 229 }
 230
 231
 232 /*
 233  * Find an nvram partition, sig can be 0 for any
 234  * partition or name can be NULL for any name, else
 235  * tries to match both
 236  */
 237 struct nvram_partition *nvram_find_partition(int sig, const char *name)
 238 {
 239         struct nvram_partition * part;
 240         struct list_head * p;
 241
 242         list_for_each(p, &nvram_part->partition) {
 243                 part = list_entry(p, struct nvram_partition, partition);
 244
 245                 if (sig && part->header.signature != sig)
 246                         continue;
 247                 if (name && 0 != strncmp(name, part->header.name, 12))
 248                         continue;
 249                 return part;
 250         }
 251         return NULL;
 252 }
 253 EXPORT_SYMBOL(nvram_find_partition);
 254
 255
 256 static int nvram_remove_os_partition(void)
 257 {
 258         struct list_head *i;
 259         struct list_head *j;
 260         struct nvram_partition * part;
 261         struct nvram_partition * cur_part;
 262         int rc;
 263
 264         list_for_each(i, &nvram_part->partition) {
 265                 part = list_entry(i, struct nvram_partition, partition);
 266                 if (part->header.signature != NVRAM_SIG_OS)
 267                         continue;
 268
 269                 /* Make os partition a free partition */
 270                 part->header.signature = NVRAM_SIG_FREE;
 271                 sprintf(part->header.name, "wwwwwwwwwwww");
 272                 part->header.checksum = nvram_checksum(&part->header);
 273
 274                 /* Merge contiguous free partitions backwards */
 275                 list_for_each_prev(j, &part->partition) {
 276                         cur_part = list_entry(j, struct nvram_partition, partition);
 277                         if (cur_part == nvram_part || cur_part->header.signature != NVRAM_SIG_FREE) {
 278                                 break;
 279                         }
 280
 281                         part->header.length += cur_part->header.length;
 282                         part->header.checksum = nvram_checksum(&part->header);
 283                         part->index = cur_part->index;
 284
 285                         list_del(&cur_part->partition);
 286                         kfree(cur_part);
 287                         j = &part->partition; /* fixup our loop */
 288                 }
 289
 290                 /* Merge contiguous free partitions forwards */
 291                 list_for_each(j, &part->partition) {
 292                         cur_part = list_entry(j, struct nvram_partition, partition);
 293                         if (cur_part == nvram_part || cur_part->header.signature != NVRAM_SIG_FREE) {
 294                                 break;
 295                         }
 296
 297                         part->header.length += cur_part->header.length;
 298                         part->header.checksum = nvram_checksum(&part->header);
 299
 300                         list_del(&cur_part->partition);
 301                         kfree(cur_part);
 302                         j = &part->partition; /* fixup our loop */
 303                 }
 304
 305                 rc = nvram_write_header(part);
 306                 if (rc <= 0) {
 307                         printk(KERN_ERR "nvram_remove_os_partition: nvram_write failed (%d)\n", rc);
 308                         return rc;
 309                 }
 310
 311         }
 312
 313         return 0;
 314 }
 315
 316 /* nvram_create_os_partition
 317  *
 318  * Create a OS linux partition to buffer error logs.
 319  * Will create a partition starting at the first free
 320  * space found if space has enough room.
 321  */
 322 static int nvram_create_os_partition(void)
 323 {
 324         struct nvram_partition *part;
 325         struct nvram_partition *new_part;
 326         struct nvram_partition *free_part = NULL;
 327         int seq_init[2] = { 0, 0 };
 328         loff_t tmp_index;
 329         long size = 0;
 330         int rc;
 331
 332         /* Find a free partition that will give us the maximum needed size
 333            If can't find one that will give us the minimum size needed */
 334         list_for_each_entry(part, &nvram_part->partition, partition) {
 335                 if (part->header.signature != NVRAM_SIG_FREE)
 336                         continue;
 337
 338                 if (part->header.length >= NVRAM_MAX_REQ) {
 339                         size = NVRAM_MAX_REQ;
 340                         free_part = part;
 341                         break;
 342                 }
 343                 if (!size && part->header.length >= NVRAM_MIN_REQ) {
 344                         size = NVRAM_MIN_REQ;
 345                         free_part = part;
 346                 }
 347         }
 348         if (!size)
 349                 return -ENOSPC;
 350
 351         /* Create our OS partition */
 352         new_part = kmalloc(sizeof(*new_part), GFP_KERNEL);
 353         if (!new_part) {
 354                 printk(KERN_ERR "nvram_create_os_partition: kmalloc failed\n");
 355                 return -ENOMEM;
 356         }
 357
 358         new_part->index = free_part->index;
 359         new_part->header.signature = NVRAM_SIG_OS;
 360         new_part->header.length = size;
 361         strcpy(new_part->header.name, "ppc64,linux");
 362         new_part->header.checksum = nvram_checksum(&new_part->header);
 363
 364         rc = nvram_write_header(new_part);
 365         if (rc <= 0) {
 366                 printk(KERN_ERR "nvram_create_os_partition: nvram_write_header \
 367                                 failed (%d)\n", rc);
 368                 return rc;
 369         }
 370
 371         /* make sure and initialize to zero the sequence number and the error
 372            type logged */
 373         tmp_index = new_part->index + NVRAM_HEADER_LEN;
 374         rc = ppc_md.nvram_write((char *)&seq_init, sizeof(seq_init), &tmp_index);
 375         if (rc <= 0) {
 376                 printk(KERN_ERR "nvram_create_os_partition: nvram_write "
 377                                 "failed (%d)\n", rc);
 378                 return rc;
 379         }
 380
 381         nvram_error_log_index = new_part->index + NVRAM_HEADER_LEN;
 382         nvram_error_log_size = ((part->header.length - 1) *
 383                                 NVRAM_BLOCK_LEN) - sizeof(struct err_log_info);
 384
 385         list_add_tail(&new_part->partition, &free_part->partition);
 386
 387         if (free_part->header.length <= size) {
 388                 list_del(&free_part->partition);
 389                 kfree(free_part);
 390                 return 0;
 391         }
 392
 393         /* Adjust the partition we stole the space from */
 394         free_part->index += size * NVRAM_BLOCK_LEN;
 395         free_part->header.length -= size;
 396         free_part->header.checksum = nvram_checksum(&free_part->header);
 397
 398         rc = nvram_write_header(free_part);
 399         if (rc <= 0) {
 400                 printk(KERN_ERR "nvram_create_os_partition: nvram_write_header "
 401                        "failed (%d)\n", rc);
 402                 return rc;
 403         }
 404
 405         return 0;
 406 }
 407
 408
 409 /* nvram_setup_partition
 410  *
 411  * This will setup the partition we need for buffering the
 412  * error logs and cleanup partitions if needed.
 413  *
 414  * The general strategy is the following:
 415  * 1.) If there is ppc64,linux partition large enough then use it.
 416  * 2.) If there is not a ppc64,linux partition large enough, search
 417  * for a free partition that is large enough.
 418  * 3.) If there is not a free partition large enough remove
 419  * _all_ OS partitions and consolidate the space.
 420  * 4.) Will first try getting a chunk that will satisfy the maximum
 421  * error log size (NVRAM_MAX_REQ).
 422  * 5.) If the max chunk cannot be allocated then try finding a chunk
 423  * that will satisfy the minum needed (NVRAM_MIN_REQ).
 424  */
 425 static int nvram_setup_partition(void)
 426 {
 427         struct list_head * p;
 428         struct nvram_partition * part;
 429         int rc;
 430
 431         /* For now, we don't do any of this on pmac, until I
 432          * have figured out if it's worth killing some unused stuffs
 433          * in our nvram, as Apple defined partitions use pretty much
 434          * all of the space
 435          */
 436         if (machine_is(powermac))
 437                 return -ENOSPC;
 438
 439         /* see if we have an OS partition that meets our needs.
 440            will try getting the max we need.  If not we'll delete
 441            partitions and try again. */
 442         list_for_each(p, &nvram_part->partition) {
 443                 part = list_entry(p, struct nvram_partition, partition);
 444                 if (part->header.signature != NVRAM_SIG_OS)
 445                         continue;
 446
 447                 if (strcmp(part->header.name, "ppc64,linux"))
 448                         continue;
 449
 450                 if (part->header.length >= NVRAM_MIN_REQ) {
 451                         /* found our partition */
 452                         nvram_error_log_index = part->index + NVRAM_HEADER_LEN;
 453                         nvram_error_log_size = ((part->header.length - 1) *
 454                                                 NVRAM_BLOCK_LEN) - sizeof(struct err_log_info);
 455                         return 0;
 456                 }
 457         }
 458
 459         /* try creating a partition with the free space we have */
 460         rc = nvram_create_os_partition();
 461         if (!rc) {
 462                 return 0;
 463         }
 464
 465         /* need to free up some space */
 466         rc = nvram_remove_os_partition();
 467         if (rc) {
 468                 return rc;
 469         }
 470
 471         /* create a partition in this new space */
 472         rc = nvram_create_os_partition();
 473         if (rc) {
 474                 printk(KERN_ERR "nvram_create_os_partition: Could not find a "
 475                        "NVRAM partition large enough\n");
 476                 return rc;
 477         }
 478
 479         return 0;
 480 }
 481
 482
 483 static int nvram_scan_partitions(void)
 484 {
 485         loff_t cur_index = 0;
 486         struct nvram_header phead;
 487         struct nvram_partition * tmp_part;
 488         unsigned char c_sum;
 489         char * header;
 490         int total_size;
 491         int err;
 492
 493         if (ppc_md.nvram_size == NULL)
 494                 return -ENODEV;
 495         total_size = ppc_md.nvram_size();
 496
 497         header = kmalloc(NVRAM_HEADER_LEN, GFP_KERNEL);
 498         if (!header) {
 499                 printk(KERN_ERR "nvram_scan_partitions: Failed kmalloc\n");
 500                 return -ENOMEM;
 501         }
 502
 503         while (cur_index < total_size) {
 504
 505                 err = ppc_md.nvram_read(header, NVRAM_HEADER_LEN, &cur_index);
 506                 if (err != NVRAM_HEADER_LEN) {
 507                         printk(KERN_ERR "nvram_scan_partitions: Error parsing "
 508                                "nvram partitions\n");
 509                         goto out;
 510                 }
 511
 512                 cur_index -= NVRAM_HEADER_LEN; /* nvram_read will advance us */
 513
 514                 memcpy(&phead, header, NVRAM_HEADER_LEN);
 515
 516                 err = 0;
 517                 c_sum = nvram_checksum(&phead);
 518                 if (c_sum != phead.checksum) {
 519                         printk(KERN_WARNING "WARNING: nvram partition checksum"
 520                                " was %02x, should be %02x!\n",
 521                                phead.checksum, c_sum);
 522                         printk(KERN_WARNING "Terminating nvram partition scan\n");
 523                         goto out;
 524                 }
 525                 if (!phead.length) {
 526                         printk(KERN_WARNING "WARNING: nvram corruption "
 527                                "detected: 0-length partition\n");
 528                         goto out;
 529                 }
 530                 tmp_part = (struct nvram_partition *)
 531                         kmalloc(sizeof(struct nvram_partition), GFP_KERNEL);
 532                 err = -ENOMEM;
 533                 if (!tmp_part) {
 534                         printk(KERN_ERR "nvram_scan_partitions: kmalloc failed\n");
 535                         goto out;
 536                 }
 537
 538                 memcpy(&tmp_part->header, &phead, NVRAM_HEADER_LEN);
 539                 tmp_part->index = cur_index;
 540                 list_add_tail(&tmp_part->partition, &nvram_part->partition);
 541
 542                 cur_index += phead.length * NVRAM_BLOCK_LEN;
 543         }
 544         err = 0;
 545
 546  out:
 547         kfree(header);
 548         return err;
 549 }
 550
 551 static int __init nvram_init(void)
 552 {
 553         int error;
 554         int rc;
 555
 556         if (ppc_md.nvram_size == NULL || ppc_md.nvram_size() <= 0)
 557                 return  -ENODEV;
 558
 559         rc = misc_register(&nvram_dev);
 560         if (rc != 0) {
 561                 printk(KERN_ERR "nvram_init: failed to register device\n");
 562                 return rc;
 563         }
 564
 565         /* initialize our anchor for the nvram partition list */
 566         nvram_part = kmalloc(sizeof(struct nvram_partition), GFP_KERNEL);
 567         if (!nvram_part) {
 568                 printk(KERN_ERR "nvram_init: Failed kmalloc\n");
 569                 return -ENOMEM;
 570         }
 571         INIT_LIST_HEAD(&nvram_part->partition);
 572
 573         /* Get all the NVRAM partitions */
 574         error = nvram_scan_partitions();
 575         if (error) {
 576                 printk(KERN_ERR "nvram_init: Failed nvram_scan_partitions\n");
 577                 return error;
 578         }
 579
 580         if(nvram_setup_partition())
 581                 printk(KERN_WARNING "nvram_init: Could not find nvram partition"
 582                        " for nvram buffered error logging.\n");
 583
 584 #ifdef DEBUG_NVRAM
 585         nvram_print_partitions("NVRAM Partitions");
 586 #endif
 587
 588         return rc;
 589 }
 590
 591 void __exit nvram_cleanup(void)
 592 {
 593         misc_deregister( &nvram_dev );
 594 }
 595
 596
 597 #ifdef CONFIG_PPC_PSERIES
 598
 599 /* nvram_write_error_log
 600  *
 601  * We need to buffer the error logs into nvram to ensure that we have
 602  * the failure information to decode.  If we have a severe error there
 603  * is no way to guarantee that the OS or the machine is in a state to
 604  * get back to user land and write the error to disk.  For example if
 605  * the SCSI device driver causes a Machine Check by writing to a bad
 606  * IO address, there is no way of guaranteeing that the device driver
 607  * is in any state that is would also be able to write the error data
 608  * captured to disk, thus we buffer it in NVRAM for analysis on the
 609  * next boot.
 610  *
 611  * In NVRAM the partition containing the error log buffer will looks like:
 612  * Header (in bytes):
 613  * +-----------+----------+--------+------------+------------------+
 614  * | signature | checksum | length | name       | data             |
 615  * |0          |1         |2      3|4         15|16        length-1|
 616  * +-----------+----------+--------+------------+------------------+
 617  *
 618  * The 'data' section would look like (in bytes):
 619  * +--------------+------------+-----------------------------------+
 620  * | event_logged | sequence # | error log                         |
 621  * |0            3|4          7|8            nvram_error_log_size-1|
 622  * +--------------+------------+-----------------------------------+
 623  *
 624  * event_logged: 0 if event has not been logged to syslog, 1 if it has
 625  * sequence #: The unique sequence # for each event. (until it wraps)
 626  * error log: The error log from event_scan
 627  */
 628 int nvram_write_error_log(char * buff, int length,
 629                           unsigned int err_type, unsigned int error_log_cnt)
 630 {
 631         int rc;
 632         loff_t tmp_index;
 633         struct err_log_info info;
 634
 635         if (nvram_error_log_index == -1) {
 636                 return -ESPIPE;
 637         }
 638
 639         if (length > nvram_error_log_size) {
 640                 length = nvram_error_log_size;
 641         }
 642
 643         info.error_type = err_type;
 644         info.seq_num = error_log_cnt;
 645
 646         tmp_index = nvram_error_log_index;
 647
 648         rc = ppc_md.nvram_write((char *)&info, sizeof(struct err_log_info), &tmp_index);
 649         if (rc <= 0) {
 650                 printk(KERN_ERR "nvram_write_error_log: Failed nvram_write (%d)\n", rc);
 651                 return rc;
 652         }
 653
 654         rc = ppc_md.nvram_write(buff, length, &tmp_index);
 655         if (rc <= 0) {
 656                 printk(KERN_ERR "nvram_write_error_log: Failed nvram_write (%d)\n", rc);
 657                 return rc;
 658         }
 659
 660         return 0;
 661 }
 662
 663 /* nvram_read_error_log
 664  *
 665  * Reads nvram for error log for at most 'length'
 666  */
 667 int nvram_read_error_log(char * buff, int length,
 668                          unsigned int * err_type, unsigned int * error_log_cnt)
 669 {
 670         int rc;
 671         loff_t tmp_index;
 672         struct err_log_info info;
 673
 674         if (nvram_error_log_index == -1)
 675                 return -1;
 676
 677         if (length > nvram_error_log_size)
 678                 length = nvram_error_log_size;
 679
 680         tmp_index = nvram_error_log_index;
 681
 682         rc = ppc_md.nvram_read((char *)&info, sizeof(struct err_log_info), &tmp_index);
 683         if (rc <= 0) {
 684                 printk(KERN_ERR "nvram_read_error_log: Failed nvram_read (%d)\n", rc);
 685                 return rc;
 686         }
 687
 688         rc = ppc_md.nvram_read(buff, length, &tmp_index);
 689         if (rc <= 0) {
 690                 printk(KERN_ERR "nvram_read_error_log: Failed nvram_read (%d)\n", rc);
 691                 return rc;
 692         }
 693
 694         *error_log_cnt = info.seq_num;
 695         *err_type = info.error_type;
 696
 697         return 0;
 698 }
 699
 700 /* This doesn't actually zero anything, but it sets the event_logged
 701  * word to tell that this event is safely in syslog.
 702  */
 703 int nvram_clear_error_log(void)
 704 {
 705         loff_t tmp_index;
 706         int clear_word = ERR_FLAG_ALREADY_LOGGED;
 707         int rc;
 708
 709         tmp_index = nvram_error_log_index;
 710
 711         rc = ppc_md.nvram_write((char *)&clear_word, sizeof(int), &tmp_index);
 712         if (rc <= 0) {
 713                 printk(KERN_ERR "nvram_clear_error_log: Failed nvram_write (%d)\n", rc);
 714                 return rc;
 715         }
 716
 717         return 0;
 718 }
 719
 720 #endif /* CONFIG_PPC_PSERIES */
 721
 722 module_init(nvram_init);
 723 module_exit(nvram_cleanup);
 724 MODULE_LICENSE("GPL");