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 int nvram_scan_partitions(void);
  38 static int nvram_setup_partition(void);
  39 static int nvram_create_os_partition(void);
  40 static int nvram_remove_os_partition(void);
  41
  42 static struct nvram_partition * nvram_part;
  43 static long nvram_error_log_index = -1;
  44 static long nvram_error_log_size = 0;
  45
  46 int no_logging = 1;     /* Until we initialize everything,
  47                          * make sure we don't try logging
  48                          * anything */
  49
  50 extern volatile int error_log_cnt;
  51
  52 struct err_log_info {
  53         int error_type;
  54         unsigned int seq_num;
  55 };
  56
  57 static loff_t dev_nvram_llseek(struct file *file, loff_t offset, int origin)
  58 {
  59         int size;
  60
  61         if (ppc_md.nvram_size == NULL)
  62                 return -ENODEV;
  63         size = ppc_md.nvram_size();
  64
  65         switch (origin) {
  66         case 1:
  67                 offset += file->f_pos;
  68                 break;
  69         case 2:
  70                 offset += size;
  71                 break;
  72         }
  73         if (offset < 0)
  74                 return -EINVAL;
  75         file->f_pos = offset;
  76         return file->f_pos;
  77 }
  78
  79
  80 static ssize_t dev_nvram_read(struct file *file, char __user *buf,
  81                           size_t count, loff_t *ppos)
  82 {
  83         ssize_t ret;
  84         char *tmp = NULL;
  85         ssize_t size;
  86
  87         ret = -ENODEV;
  88         if (!ppc_md.nvram_size)
  89                 goto out;
  90
  91         ret = 0;
  92         size = ppc_md.nvram_size();
  93         if (*ppos >= size || size < 0)
  94                 goto out;
  95
  96         count = min_t(size_t, count, size - *ppos);
  97         count = min(count, PAGE_SIZE);
  98
  99         ret = -ENOMEM;
 100         tmp = kmalloc(count, GFP_KERNEL);
 101         if (!tmp)
 102                 goto out;
 103
 104         ret = ppc_md.nvram_read(tmp, count, ppos);
 105         if (ret <= 0)
 106                 goto out;
 107
 108         if (copy_to_user(buf, tmp, ret))
 109                 ret = -EFAULT;
 110
 111 out:
 112         kfree(tmp);
 113         return ret;
 114
 115 }
 116
 117 static ssize_t dev_nvram_write(struct file *file, const char __user *buf,
 118                           size_t count, loff_t *ppos)
 119 {
 120         ssize_t ret;
 121         char *tmp = NULL;
 122         ssize_t size;
 123
 124         ret = -ENODEV;
 125         if (!ppc_md.nvram_size)
 126                 goto out;
 127
 128         ret = 0;
 129         size = ppc_md.nvram_size();
 130         if (*ppos >= size || size < 0)
 131                 goto out;
 132
 133         count = min_t(size_t, count, size - *ppos);
 134         count = min(count, PAGE_SIZE);
 135
 136         ret = -ENOMEM;
 137         tmp = kmalloc(count, GFP_KERNEL);
 138         if (!tmp)
 139                 goto out;
 140
 141         ret = -EFAULT;
 142         if (copy_from_user(tmp, buf, count))
 143                 goto out;
 144
 145         ret = ppc_md.nvram_write(tmp, count, ppos);
 146
 147 out:
 148         kfree(tmp);
 149         return ret;
 150
 151 }
 152
 153 static int dev_nvram_ioctl(struct inode *inode, struct file *file,
 154         unsigned int cmd, unsigned long arg)
 155 {
 156         switch(cmd) {
 157 #ifdef CONFIG_PPC_PMAC
 158         case OBSOLETE_PMAC_NVRAM_GET_OFFSET:
 159                 printk(KERN_WARNING "nvram: Using obsolete PMAC_NVRAM_GET_OFFSET ioctl\n");
 160         case IOC_NVRAM_GET_OFFSET: {
 161                 int part, offset;
 162
 163                 if (!machine_is(powermac))
 164                         return -EINVAL;
 165                 if (copy_from_user(&part, (void __user*)arg, sizeof(part)) != 0)
 166                         return -EFAULT;
 167                 if (part < pmac_nvram_OF || part > pmac_nvram_NR)
 168                         return -EINVAL;
 169                 offset = pmac_get_partition(part);
 170                 if (offset < 0)
 171                         return offset;
 172                 if (copy_to_user((void __user*)arg, &offset, sizeof(offset)) != 0)
 173                         return -EFAULT;
 174                 return 0;
 175         }
 176 #endif /* CONFIG_PPC_PMAC */
 177         default:
 178                 return -EINVAL;
 179         }
 180 }
 181
 182 struct file_operations nvram_fops = {
 183         .owner =        THIS_MODULE,
 184         .llseek =       dev_nvram_llseek,
 185         .read =         dev_nvram_read,
 186         .write =        dev_nvram_write,
 187         .ioctl =        dev_nvram_ioctl,
 188 };
 189
 190 static struct miscdevice nvram_dev = {
 191         NVRAM_MINOR,
 192         "nvram",
 193         &nvram_fops
 194 };
 195
 196
 197 #ifdef DEBUG_NVRAM
 198 static void nvram_print_partitions(char * label)
 199 {
 200         struct list_head * p;
 201         struct nvram_partition * tmp_part;
 202
 203         printk(KERN_WARNING "--------%s---------\n", label);
 204         printk(KERN_WARNING "indx\t\tsig\tchks\tlen\tname\n");
 205         list_for_each(p, &nvram_part->partition) {
 206                 tmp_part = list_entry(p, struct nvram_partition, partition);
 207                 printk(KERN_WARNING "%4d    \t%02x\t%02x\t%d\t%s\n",
 208                        tmp_part->index, tmp_part->header.signature,
 209                        tmp_part->header.checksum, tmp_part->header.length,
 210                        tmp_part->header.name);
 211         }
 212 }
 213 #endif
 214
 215
 216 static int nvram_write_header(struct nvram_partition * part)
 217 {
 218         loff_t tmp_index;
 219         int rc;
 220
 221         tmp_index = part->index;
 222         rc = ppc_md.nvram_write((char *)&part->header, NVRAM_HEADER_LEN, &tmp_index);
 223
 224         return rc;
 225 }
 226
 227
 228 static unsigned char nvram_checksum(struct nvram_header *p)
 229 {
 230         unsigned int c_sum, c_sum2;
 231         unsigned short *sp = (unsigned short *)p->name; /* assume 6 shorts */
 232         c_sum = p->signature + p->length + sp[0] + sp[1] + sp[2] + sp[3] + sp[4] + sp[5];
 233
 234         /* The sum may have spilled into the 3rd byte.  Fold it back. */
 235         c_sum = ((c_sum & 0xffff) + (c_sum >> 16)) & 0xffff;
 236         /* The sum cannot exceed 2 bytes.  Fold it into a checksum */
 237         c_sum2 = (c_sum >> 8) + (c_sum << 8);
 238         c_sum = ((c_sum + c_sum2) >> 8) & 0xff;
 239         return c_sum;
 240 }
 241
 242
 243 /*
 244  * Find an nvram partition, sig can be 0 for any
 245  * partition or name can be NULL for any name, else
 246  * tries to match both
 247  */
 248 struct nvram_partition *nvram_find_partition(int sig, const char *name)
 249 {
 250         struct nvram_partition * part;
 251         struct list_head * p;
 252
 253         list_for_each(p, &nvram_part->partition) {
 254                 part = list_entry(p, struct nvram_partition, partition);
 255
 256                 if (sig && part->header.signature != sig)
 257                         continue;
 258                 if (name && 0 != strncmp(name, part->header.name, 12))
 259                         continue;
 260                 return part;
 261         }
 262         return NULL;
 263 }
 264 EXPORT_SYMBOL(nvram_find_partition);
 265
 266
 267 static int nvram_remove_os_partition(void)
 268 {
 269         struct list_head *i;
 270         struct list_head *j;
 271         struct nvram_partition * part;
 272         struct nvram_partition * cur_part;
 273         int rc;
 274
 275         list_for_each(i, &nvram_part->partition) {
 276                 part = list_entry(i, struct nvram_partition, partition);
 277                 if (part->header.signature != NVRAM_SIG_OS)
 278                         continue;
 279
 280                 /* Make os partition a free partition */
 281                 part->header.signature = NVRAM_SIG_FREE;
 282                 sprintf(part->header.name, "wwwwwwwwwwww");
 283                 part->header.checksum = nvram_checksum(&part->header);
 284
 285                 /* Merge contiguous free partitions backwards */
 286                 list_for_each_prev(j, &part->partition) {
 287                         cur_part = list_entry(j, struct nvram_partition, partition);
 288                         if (cur_part == nvram_part || cur_part->header.signature != NVRAM_SIG_FREE) {
 289                                 break;
 290                         }
 291
 292                         part->header.length += cur_part->header.length;
 293                         part->header.checksum = nvram_checksum(&part->header);
 294                         part->index = cur_part->index;
 295
 296                         list_del(&cur_part->partition);
 297                         kfree(cur_part);
 298                         j = &part->partition; /* fixup our loop */
 299                 }
 300
 301                 /* Merge contiguous free partitions forwards */
 302                 list_for_each(j, &part->partition) {
 303                         cur_part = list_entry(j, struct nvram_partition, partition);
 304                         if (cur_part == nvram_part || cur_part->header.signature != NVRAM_SIG_FREE) {
 305                                 break;
 306                         }
 307
 308                         part->header.length += cur_part->header.length;
 309                         part->header.checksum = nvram_checksum(&part->header);
 310
 311                         list_del(&cur_part->partition);
 312                         kfree(cur_part);
 313                         j = &part->partition; /* fixup our loop */
 314                 }
 315
 316                 rc = nvram_write_header(part);
 317                 if (rc <= 0) {
 318                         printk(KERN_ERR "nvram_remove_os_partition: nvram_write failed (%d)\n", rc);
 319                         return rc;
 320                 }
 321
 322         }
 323
 324         return 0;
 325 }
 326
 327 /* nvram_create_os_partition
 328  *
 329  * Create a OS linux partition to buffer error logs.
 330  * Will create a partition starting at the first free
 331  * space found if space has enough room.
 332  */
 333 static int nvram_create_os_partition(void)
 334 {
 335         struct nvram_partition *part;
 336         struct nvram_partition *new_part;
 337         struct nvram_partition *free_part = NULL;
 338         int seq_init[2] = { 0, 0 };
 339         loff_t tmp_index;
 340         long size = 0;
 341         int rc;
 342
 343         /* Find a free partition that will give us the maximum needed size
 344            If can't find one that will give us the minimum size needed */
 345         list_for_each_entry(part, &nvram_part->partition, partition) {
 346                 if (part->header.signature != NVRAM_SIG_FREE)
 347                         continue;
 348
 349                 if (part->header.length >= NVRAM_MAX_REQ) {
 350                         size = NVRAM_MAX_REQ;
 351                         free_part = part;
 352                         break;
 353                 }
 354                 if (!size && part->header.length >= NVRAM_MIN_REQ) {
 355                         size = NVRAM_MIN_REQ;
 356                         free_part = part;
 357                 }
 358         }
 359         if (!size)
 360                 return -ENOSPC;
 361
 362         /* Create our OS partition */
 363         new_part = kmalloc(sizeof(*new_part), GFP_KERNEL);
 364         if (!new_part) {
 365                 printk(KERN_ERR "nvram_create_os_partition: kmalloc failed\n");
 366                 return -ENOMEM;
 367         }
 368
 369         new_part->index = free_part->index;
 370         new_part->header.signature = NVRAM_SIG_OS;
 371         new_part->header.length = size;
 372         strcpy(new_part->header.name, "ppc64,linux");
 373         new_part->header.checksum = nvram_checksum(&new_part->header);
 374
 375         rc = nvram_write_header(new_part);
 376         if (rc <= 0) {
 377                 printk(KERN_ERR "nvram_create_os_partition: nvram_write_header \
 378                                 failed (%d)\n", rc);
 379                 return rc;
 380         }
 381
 382         /* make sure and initialize to zero the sequence number and the error
 383            type logged */
 384         tmp_index = new_part->index + NVRAM_HEADER_LEN;
 385         rc = ppc_md.nvram_write((char *)&seq_init, sizeof(seq_init), &tmp_index);
 386         if (rc <= 0) {
 387                 printk(KERN_ERR "nvram_create_os_partition: nvram_write "
 388                                 "failed (%d)\n", rc);
 389                 return rc;
 390         }
 391
 392         nvram_error_log_index = new_part->index + NVRAM_HEADER_LEN;
 393         nvram_error_log_size = ((part->header.length - 1) *
 394                                 NVRAM_BLOCK_LEN) - sizeof(struct err_log_info);
 395
 396         list_add_tail(&new_part->partition, &free_part->partition);
 397
 398         if (free_part->header.length <= size) {
 399                 list_del(&free_part->partition);
 400                 kfree(free_part);
 401                 return 0;
 402         }
 403
 404         /* Adjust the partition we stole the space from */
 405         free_part->index += size * NVRAM_BLOCK_LEN;
 406         free_part->header.length -= size;
 407         free_part->header.checksum = nvram_checksum(&free_part->header);
 408
 409         rc = nvram_write_header(free_part);
 410         if (rc <= 0) {
 411                 printk(KERN_ERR "nvram_create_os_partition: nvram_write_header "
 412                        "failed (%d)\n", rc);
 413                 return rc;
 414         }
 415
 416         return 0;
 417 }
 418
 419
 420 /* nvram_setup_partition
 421  *
 422  * This will setup the partition we need for buffering the
 423  * error logs and cleanup partitions if needed.
 424  *
 425  * The general strategy is the following:
 426  * 1.) If there is ppc64,linux partition large enough then use it.
 427  * 2.) If there is not a ppc64,linux partition large enough, search
 428  * for a free partition that is large enough.
 429  * 3.) If there is not a free partition large enough remove
 430  * _all_ OS partitions and consolidate the space.
 431  * 4.) Will first try getting a chunk that will satisfy the maximum
 432  * error log size (NVRAM_MAX_REQ).
 433  * 5.) If the max chunk cannot be allocated then try finding a chunk
 434  * that will satisfy the minum needed (NVRAM_MIN_REQ).
 435  */
 436 static int nvram_setup_partition(void)
 437 {
 438         struct list_head * p;
 439         struct nvram_partition * part;
 440         int rc;
 441
 442         /* For now, we don't do any of this on pmac, until I
 443          * have figured out if it's worth killing some unused stuffs
 444          * in our nvram, as Apple defined partitions use pretty much
 445          * all of the space
 446          */
 447         if (machine_is(powermac))
 448                 return -ENOSPC;
 449
 450         /* see if we have an OS partition that meets our needs.
 451            will try getting the max we need.  If not we'll delete
 452            partitions and try again. */
 453         list_for_each(p, &nvram_part->partition) {
 454                 part = list_entry(p, struct nvram_partition, partition);
 455                 if (part->header.signature != NVRAM_SIG_OS)
 456                         continue;
 457
 458                 if (strcmp(part->header.name, "ppc64,linux"))
 459                         continue;
 460
 461                 if (part->header.length >= NVRAM_MIN_REQ) {
 462                         /* found our partition */
 463                         nvram_error_log_index = part->index + NVRAM_HEADER_LEN;
 464                         nvram_error_log_size = ((part->header.length - 1) *
 465                                                 NVRAM_BLOCK_LEN) - sizeof(struct err_log_info);
 466                         return 0;
 467                 }
 468         }
 469
 470         /* try creating a partition with the free space we have */
 471         rc = nvram_create_os_partition();
 472         if (!rc) {
 473                 return 0;
 474         }
 475
 476         /* need to free up some space */
 477         rc = nvram_remove_os_partition();
 478         if (rc) {
 479                 return rc;
 480         }
 481
 482         /* create a partition in this new space */
 483         rc = nvram_create_os_partition();
 484         if (rc) {
 485                 printk(KERN_ERR "nvram_create_os_partition: Could not find a "
 486                        "NVRAM partition large enough\n");
 487                 return rc;
 488         }
 489
 490         return 0;
 491 }
 492
 493
 494 static int nvram_scan_partitions(void)
 495 {
 496         loff_t cur_index = 0;
 497         struct nvram_header phead;
 498         struct nvram_partition * tmp_part;
 499         unsigned char c_sum;
 500         char * header;
 501         int total_size;
 502         int err;
 503
 504         if (ppc_md.nvram_size == NULL)
 505                 return -ENODEV;
 506         total_size = ppc_md.nvram_size();
 507
 508         header = (char *) kmalloc(NVRAM_HEADER_LEN, GFP_KERNEL);
 509         if (!header) {
 510                 printk(KERN_ERR "nvram_scan_partitions: Failed kmalloc\n");
 511                 return -ENOMEM;
 512         }
 513
 514         while (cur_index < total_size) {
 515
 516                 err = ppc_md.nvram_read(header, NVRAM_HEADER_LEN, &cur_index);
 517                 if (err != NVRAM_HEADER_LEN) {
 518                         printk(KERN_ERR "nvram_scan_partitions: Error parsing "
 519                                "nvram partitions\n");
 520                         goto out;
 521                 }
 522
 523                 cur_index -= NVRAM_HEADER_LEN; /* nvram_read will advance us */
 524
 525                 memcpy(&phead, header, NVRAM_HEADER_LEN);
 526
 527                 err = 0;
 528                 c_sum = nvram_checksum(&phead);
 529                 if (c_sum != phead.checksum) {
 530                         printk(KERN_WARNING "WARNING: nvram partition checksum"
 531                                " was %02x, should be %02x!\n",
 532                                phead.checksum, c_sum);
 533                         printk(KERN_WARNING "Terminating nvram partition scan\n");
 534                         goto out;
 535                 }
 536                 if (!phead.length) {
 537                         printk(KERN_WARNING "WARNING: nvram corruption "
 538                                "detected: 0-length partition\n");
 539                         goto out;
 540                 }
 541                 tmp_part = (struct nvram_partition *)
 542                         kmalloc(sizeof(struct nvram_partition), GFP_KERNEL);
 543                 err = -ENOMEM;
 544                 if (!tmp_part) {
 545                         printk(KERN_ERR "nvram_scan_partitions: kmalloc failed\n");
 546                         goto out;
 547                 }
 548
 549                 memcpy(&tmp_part->header, &phead, NVRAM_HEADER_LEN);
 550                 tmp_part->index = cur_index;
 551                 list_add_tail(&tmp_part->partition, &nvram_part->partition);
 552
 553                 cur_index += phead.length * NVRAM_BLOCK_LEN;
 554         }
 555         err = 0;
 556
 557  out:
 558         kfree(header);
 559         return err;
 560 }
 561
 562 static int __init nvram_init(void)
 563 {
 564         int error;
 565         int rc;
 566
 567         if (ppc_md.nvram_size == NULL || ppc_md.nvram_size() <= 0)
 568                 return  -ENODEV;
 569
 570         rc = misc_register(&nvram_dev);
 571         if (rc != 0) {
 572                 printk(KERN_ERR "nvram_init: failed to register device\n");
 573                 return rc;
 574         }
 575
 576         /* initialize our anchor for the nvram partition list */
 577         nvram_part = (struct nvram_partition *) kmalloc(sizeof(struct nvram_partition), GFP_KERNEL);
 578         if (!nvram_part) {
 579                 printk(KERN_ERR "nvram_init: Failed kmalloc\n");
 580                 return -ENOMEM;
 581         }
 582         INIT_LIST_HEAD(&nvram_part->partition);
 583
 584         /* Get all the NVRAM partitions */
 585         error = nvram_scan_partitions();
 586         if (error) {
 587                 printk(KERN_ERR "nvram_init: Failed nvram_scan_partitions\n");
 588                 return error;
 589         }
 590
 591         if(nvram_setup_partition())
 592                 printk(KERN_WARNING "nvram_init: Could not find nvram partition"
 593                        " for nvram buffered error logging.\n");
 594
 595 #ifdef DEBUG_NVRAM
 596         nvram_print_partitions("NVRAM Partitions");
 597 #endif
 598
 599         return rc;
 600 }
 601
 602 void __exit nvram_cleanup(void)
 603 {
 604         misc_deregister( &nvram_dev );
 605 }
 606
 607
 608 #ifdef CONFIG_PPC_PSERIES
 609
 610 /* nvram_write_error_log
 611  *
 612  * We need to buffer the error logs into nvram to ensure that we have
 613  * the failure information to decode.  If we have a severe error there
 614  * is no way to guarantee that the OS or the machine is in a state to
 615  * get back to user land and write the error to disk.  For example if
 616  * the SCSI device driver causes a Machine Check by writing to a bad
 617  * IO address, there is no way of guaranteeing that the device driver
 618  * is in any state that is would also be able to write the error data
 619  * captured to disk, thus we buffer it in NVRAM for analysis on the
 620  * next boot.
 621  *
 622  * In NVRAM the partition containing the error log buffer will looks like:
 623  * Header (in bytes):
 624  * +-----------+----------+--------+------------+------------------+
 625  * | signature | checksum | length | name       | data             |
 626  * |0          |1         |2      3|4         15|16        length-1|
 627  * +-----------+----------+--------+------------+------------------+
 628  *
 629  * The 'data' section would look like (in bytes):
 630  * +--------------+------------+-----------------------------------+
 631  * | event_logged | sequence # | error log                         |
 632  * |0            3|4          7|8            nvram_error_log_size-1|
 633  * +--------------+------------+-----------------------------------+
 634  *
 635  * event_logged: 0 if event has not been logged to syslog, 1 if it has
 636  * sequence #: The unique sequence # for each event. (until it wraps)
 637  * error log: The error log from event_scan
 638  */
 639 int nvram_write_error_log(char * buff, int length, unsigned int err_type)
 640 {
 641         int rc;
 642         loff_t tmp_index;
 643         struct err_log_info info;
 644
 645         if (no_logging) {
 646                 return -EPERM;
 647         }
 648
 649         if (nvram_error_log_index == -1) {
 650                 return -ESPIPE;
 651         }
 652
 653         if (length > nvram_error_log_size) {
 654                 length = nvram_error_log_size;
 655         }
 656
 657         info.error_type = err_type;
 658         info.seq_num = error_log_cnt;
 659
 660         tmp_index = nvram_error_log_index;
 661
 662         rc = ppc_md.nvram_write((char *)&info, sizeof(struct err_log_info), &tmp_index);
 663         if (rc <= 0) {
 664                 printk(KERN_ERR "nvram_write_error_log: Failed nvram_write (%d)\n", rc);
 665                 return rc;
 666         }
 667
 668         rc = ppc_md.nvram_write(buff, length, &tmp_index);
 669         if (rc <= 0) {
 670                 printk(KERN_ERR "nvram_write_error_log: Failed nvram_write (%d)\n", rc);
 671                 return rc;
 672         }
 673
 674         return 0;
 675 }
 676
 677 /* nvram_read_error_log
 678  *
 679  * Reads nvram for error log for at most 'length'
 680  */
 681 int nvram_read_error_log(char * buff, int length, unsigned int * err_type)
 682 {
 683         int rc;
 684         loff_t tmp_index;
 685         struct err_log_info info;
 686
 687         if (nvram_error_log_index == -1)
 688                 return -1;
 689
 690         if (length > nvram_error_log_size)
 691                 length = nvram_error_log_size;
 692
 693         tmp_index = nvram_error_log_index;
 694
 695         rc = ppc_md.nvram_read((char *)&info, sizeof(struct err_log_info), &tmp_index);
 696         if (rc <= 0) {
 697                 printk(KERN_ERR "nvram_read_error_log: Failed nvram_read (%d)\n", rc);
 698                 return rc;
 699         }
 700
 701         rc = ppc_md.nvram_read(buff, length, &tmp_index);
 702         if (rc <= 0) {
 703                 printk(KERN_ERR "nvram_read_error_log: Failed nvram_read (%d)\n", rc);
 704                 return rc;
 705         }
 706
 707         error_log_cnt = info.seq_num;
 708         *err_type = info.error_type;
 709
 710         return 0;
 711 }
 712
 713 /* This doesn't actually zero anything, but it sets the event_logged
 714  * word to tell that this event is safely in syslog.
 715  */
 716 int nvram_clear_error_log(void)
 717 {
 718         loff_t tmp_index;
 719         int clear_word = ERR_FLAG_ALREADY_LOGGED;
 720         int rc;
 721
 722         tmp_index = nvram_error_log_index;
 723
 724         rc = ppc_md.nvram_write((char *)&clear_word, sizeof(int), &tmp_index);
 725         if (rc <= 0) {
 726                 printk(KERN_ERR "nvram_clear_error_log: Failed nvram_write (%d)\n", rc);
 727                 return rc;
 728         }
 729
 730         return 0;
 731 }
 732
 733 #endif /* CONFIG_PPC_PSERIES */
 734
 735 module_init(nvram_init);
 736 module_exit(nvram_cleanup);
 737 MODULE_LICENSE("GPL");