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 #define NVRAM_HEADER_LEN        sizeof(struct nvram_header)
  38 #define NVRAM_BLOCK_LEN         NVRAM_HEADER_LEN
  39
  40 /* If change this size, then change the size of NVNAME_LEN */
  41 struct nvram_header {
  42         unsigned char signature;
  43         unsigned char checksum;
  44         unsigned short length;
  45         /* Terminating null required only for names < 12 chars. */
  46         char name[12];
  47 };
  48
  49 struct nvram_partition {
  50         struct list_head partition;
  51         struct nvram_header header;
  52         unsigned int index;
  53 };
  54
  55 static LIST_HEAD(nvram_partitions);
  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         if (!ppc_md.nvram_size) {
  88                 ret = -ENODEV;
  89                 goto out;
  90         }
  91
  92         size = ppc_md.nvram_size();
  93         if (size < 0) {
  94                 ret = size;
  95                 goto out;
  96         }
  97
  98         if (*ppos >= size) {
  99                 ret = 0;
 100                 goto out;
 101         }
 102
 103         count = min_t(size_t, count, size - *ppos);
 104         count = min(count, PAGE_SIZE);
 105
 106         tmp = kmalloc(count, GFP_KERNEL);
 107         if (!tmp) {
 108                 ret = -ENOMEM;
 109                 goto out;
 110         }
 111
 112         ret = ppc_md.nvram_read(tmp, count, ppos);
 113         if (ret <= 0)
 114                 goto out;
 115
 116         if (copy_to_user(buf, tmp, ret))
 117                 ret = -EFAULT;
 118
 119 out:
 120         kfree(tmp);
 121         return ret;
 122
 123 }
 124
 125 static ssize_t dev_nvram_write(struct file *file, const char __user *buf,
 126                           size_t count, loff_t *ppos)
 127 {
 128         ssize_t ret;
 129         char *tmp = NULL;
 130         ssize_t size;
 131
 132         ret = -ENODEV;
 133         if (!ppc_md.nvram_size)
 134                 goto out;
 135
 136         ret = 0;
 137         size = ppc_md.nvram_size();
 138         if (*ppos >= size || size < 0)
 139                 goto out;
 140
 141         count = min_t(size_t, count, size - *ppos);
 142         count = min(count, PAGE_SIZE);
 143
 144         ret = -ENOMEM;
 145         tmp = kmalloc(count, GFP_KERNEL);
 146         if (!tmp)
 147                 goto out;
 148
 149         ret = -EFAULT;
 150         if (copy_from_user(tmp, buf, count))
 151                 goto out;
 152
 153         ret = ppc_md.nvram_write(tmp, count, ppos);
 154
 155 out:
 156         kfree(tmp);
 157         return ret;
 158
 159 }
 160
 161 static long dev_nvram_ioctl(struct file *file, unsigned int cmd,
 162                             unsigned long arg)
 163 {
 164         switch(cmd) {
 165 #ifdef CONFIG_PPC_PMAC
 166         case OBSOLETE_PMAC_NVRAM_GET_OFFSET:
 167                 printk(KERN_WARNING "nvram: Using obsolete PMAC_NVRAM_GET_OFFSET ioctl\n");
 168         case IOC_NVRAM_GET_OFFSET: {
 169                 int part, offset;
 170
 171                 if (!machine_is(powermac))
 172                         return -EINVAL;
 173                 if (copy_from_user(&part, (void __user*)arg, sizeof(part)) != 0)
 174                         return -EFAULT;
 175                 if (part < pmac_nvram_OF || part > pmac_nvram_NR)
 176                         return -EINVAL;
 177                 offset = pmac_get_partition(part);
 178                 if (offset < 0)
 179                         return offset;
 180                 if (copy_to_user((void __user*)arg, &offset, sizeof(offset)) != 0)
 181                         return -EFAULT;
 182                 return 0;
 183         }
 184 #endif /* CONFIG_PPC_PMAC */
 185         default:
 186                 return -EINVAL;
 187         }
 188 }
 189
 190 const struct file_operations nvram_fops = {
 191         .owner          = THIS_MODULE,
 192         .llseek         = dev_nvram_llseek,
 193         .read           = dev_nvram_read,
 194         .write          = dev_nvram_write,
 195         .unlocked_ioctl = dev_nvram_ioctl,
 196 };
 197
 198 static struct miscdevice nvram_dev = {
 199         NVRAM_MINOR,
 200         "nvram",
 201         &nvram_fops
 202 };
 203
 204
 205 #ifdef DEBUG_NVRAM
 206 static void __init nvram_print_partitions(char * label)
 207 {
 208         struct nvram_partition * tmp_part;
 209
 210         printk(KERN_WARNING "--------%s---------\n", label);
 211         printk(KERN_WARNING "indx\t\tsig\tchks\tlen\tname\n");
 212         list_for_each_entry(tmp_part, &nvram_partitions, partition) {
 213                 printk(KERN_WARNING "%4d    \t%02x\t%02x\t%d\t%12s\n",
 214                        tmp_part->index, tmp_part->header.signature,
 215                        tmp_part->header.checksum, tmp_part->header.length,
 216                        tmp_part->header.name);
 217         }
 218 }
 219 #endif
 220
 221
 222 static int __init nvram_write_header(struct nvram_partition * part)
 223 {
 224         loff_t tmp_index;
 225         int rc;
 226
 227         tmp_index = part->index;
 228         rc = ppc_md.nvram_write((char *)&part->header, NVRAM_HEADER_LEN, &tmp_index);
 229
 230         return rc;
 231 }
 232
 233
 234 static unsigned char __init nvram_checksum(struct nvram_header *p)
 235 {
 236         unsigned int c_sum, c_sum2;
 237         unsigned short *sp = (unsigned short *)p->name; /* assume 6 shorts */
 238         c_sum = p->signature + p->length + sp[0] + sp[1] + sp[2] + sp[3] + sp[4] + sp[5];
 239
 240         /* The sum may have spilled into the 3rd byte.  Fold it back. */
 241         c_sum = ((c_sum & 0xffff) + (c_sum >> 16)) & 0xffff;
 242         /* The sum cannot exceed 2 bytes.  Fold it into a checksum */
 243         c_sum2 = (c_sum >> 8) + (c_sum << 8);
 244         c_sum = ((c_sum + c_sum2) >> 8) & 0xff;
 245         return c_sum;
 246 }
 247
 248 /*
 249  * Per the criteria passed via nvram_remove_partition(), should this
 250  * partition be removed?  1=remove, 0=keep
 251  */
 252 static int nvram_can_remove_partition(struct nvram_partition *part,
 253                 const char *name, int sig, const char *exceptions[])
 254 {
 255         if (part->header.signature != sig)
 256                 return 0;
 257         if (name) {
 258                 if (strncmp(name, part->header.name, 12))
 259                         return 0;
 260         } else if (exceptions) {
 261                 const char **except;
 262                 for (except = exceptions; *except; except++) {
 263                         if (!strncmp(*except, part->header.name, 12))
 264                                 return 0;
 265                 }
 266         }
 267         return 1;
 268 }
 269
 270 /**
 271  * nvram_remove_partition - Remove one or more partitions in nvram
 272  * @name: name of the partition to remove, or NULL for a
 273  *        signature only match
 274  * @sig: signature of the partition(s) to remove
 275  * @exceptions: When removing all partitions with a matching signature,
 276  *        leave these alone.
 277  */
 278
 279 int __init nvram_remove_partition(const char *name, int sig,
 280                                                 const char *exceptions[])
 281 {
 282         struct nvram_partition *part, *prev, *tmp;
 283         int rc;
 284
 285         list_for_each_entry(part, &nvram_partitions, partition) {
 286                 if (!nvram_can_remove_partition(part, name, sig, exceptions))
 287                         continue;
 288
 289                 /* Make partition a free partition */
 290                 part->header.signature = NVRAM_SIG_FREE;
 291                 strncpy(part->header.name, "wwwwwwwwwwww", 12);
 292                 part->header.checksum = nvram_checksum(&part->header);
 293                 rc = nvram_write_header(part);
 294                 if (rc <= 0) {
 295                         printk(KERN_ERR "nvram_remove_partition: nvram_write failed (%d)\n", rc);
 296                         return rc;
 297                 }
 298         }
 299
 300         /* Merge contiguous ones */
 301         prev = NULL;
 302         list_for_each_entry_safe(part, tmp, &nvram_partitions, partition) {
 303                 if (part->header.signature != NVRAM_SIG_FREE) {
 304                         prev = NULL;
 305                         continue;
 306                 }
 307                 if (prev) {
 308                         prev->header.length += part->header.length;
 309                         prev->header.checksum = nvram_checksum(&part->header);
 310                         rc = nvram_write_header(part);
 311                         if (rc <= 0) {
 312                                 printk(KERN_ERR "nvram_remove_partition: nvram_write failed (%d)\n", rc);
 313                                 return rc;
 314                         }
 315                         list_del(&part->partition);
 316                         kfree(part);
 317                 } else
 318                         prev = part;
 319         }
 320
 321         return 0;
 322 }
 323
 324 /**
 325  * nvram_create_partition - Create a partition in nvram
 326  * @name: name of the partition to create
 327  * @sig: signature of the partition to create
 328  * @req_size: size of data to allocate in bytes
 329  * @min_size: minimum acceptable size (0 means req_size)
 330  *
 331  * Returns a negative error code or a positive nvram index
 332  * of the beginning of the data area of the newly created
 333  * partition. If you provided a min_size smaller than req_size
 334  * you need to query for the actual size yourself after the
 335  * call using nvram_partition_get_size().
 336  */
 337 loff_t __init nvram_create_partition(const char *name, int sig,
 338                                      int req_size, int min_size)
 339 {
 340         struct nvram_partition *part;
 341         struct nvram_partition *new_part;
 342         struct nvram_partition *free_part = NULL;
 343         static char nv_init_vals[16];
 344         loff_t tmp_index;
 345         long size = 0;
 346         int rc;
 347
 348         /* Convert sizes from bytes to blocks */
 349         req_size = _ALIGN_UP(req_size, NVRAM_BLOCK_LEN) / NVRAM_BLOCK_LEN;
 350         min_size = _ALIGN_UP(min_size, NVRAM_BLOCK_LEN) / NVRAM_BLOCK_LEN;
 351
 352         /* If no minimum size specified, make it the same as the
 353          * requested size
 354          */
 355         if (min_size == 0)
 356                 min_size = req_size;
 357         if (min_size > req_size)
 358                 return -EINVAL;
 359
 360         /* Now add one block to each for the header */
 361         req_size += 1;
 362         min_size += 1;
 363
 364         /* Find a free partition that will give us the maximum needed size
 365            If can't find one that will give us the minimum size needed */
 366         list_for_each_entry(part, &nvram_partitions, partition) {
 367                 if (part->header.signature != NVRAM_SIG_FREE)
 368                         continue;
 369
 370                 if (part->header.length >= req_size) {
 371                         size = req_size;
 372                         free_part = part;
 373                         break;
 374                 }
 375                 if (part->header.length > size &&
 376                     part->header.length >= min_size) {
 377                         size = part->header.length;
 378                         free_part = part;
 379                 }
 380         }
 381         if (!size)
 382                 return -ENOSPC;
 383
 384         /* Create our OS partition */
 385         new_part = kmalloc(sizeof(*new_part), GFP_KERNEL);
 386         if (!new_part) {
 387                 pr_err("nvram_create_os_partition: kmalloc failed\n");
 388                 return -ENOMEM;
 389         }
 390
 391         new_part->index = free_part->index;
 392         new_part->header.signature = sig;
 393         new_part->header.length = size;
 394         strncpy(new_part->header.name, name, 12);
 395         new_part->header.checksum = nvram_checksum(&new_part->header);
 396
 397         rc = nvram_write_header(new_part);
 398         if (rc <= 0) {
 399                 pr_err("nvram_create_os_partition: nvram_write_header "
 400                        "failed (%d)\n", rc);
 401                 return rc;
 402         }
 403         list_add_tail(&new_part->partition, &free_part->partition);
 404
 405         /* Adjust or remove the partition we stole the space from */
 406         if (free_part->header.length > size) {
 407                 free_part->index += size * NVRAM_BLOCK_LEN;
 408                 free_part->header.length -= size;
 409                 free_part->header.checksum = nvram_checksum(&free_part->header);
 410                 rc = nvram_write_header(free_part);
 411                 if (rc <= 0) {
 412                         pr_err("nvram_create_os_partition: nvram_write_header "
 413                                "failed (%d)\n", rc);
 414                         return rc;
 415                 }
 416         } else {
 417                 list_del(&free_part->partition);
 418                 kfree(free_part);
 419         }
 420
 421         /* Clear the new partition */
 422         for (tmp_index = new_part->index + NVRAM_HEADER_LEN;
 423              tmp_index <  ((size - 1) * NVRAM_BLOCK_LEN);
 424              tmp_index += NVRAM_BLOCK_LEN) {
 425                 rc = ppc_md.nvram_write(nv_init_vals, NVRAM_BLOCK_LEN, &tmp_index);
 426                 if (rc <= 0) {
 427                         pr_err("nvram_create_partition: nvram_write failed (%d)\n", rc);
 428                         return rc;
 429                 }
 430         }
 431
 432         return new_part->index + NVRAM_HEADER_LEN;
 433 }
 434
 435 /**
 436  * nvram_get_partition_size - Get the data size of an nvram partition
 437  * @data_index: This is the offset of the start of the data of
 438  *              the partition. The same value that is returned by
 439  *              nvram_create_partition().
 440  */
 441 int nvram_get_partition_size(loff_t data_index)
 442 {
 443         struct nvram_partition *part;
 444
 445         list_for_each_entry(part, &nvram_partitions, partition) {
 446                 if (part->index + NVRAM_HEADER_LEN == data_index)
 447                         return (part->header.length - 1) * NVRAM_BLOCK_LEN;
 448         }
 449         return -1;
 450 }
 451
 452
 453 /**
 454  * nvram_find_partition - Find an nvram partition by signature and name
 455  * @name: Name of the partition or NULL for any name
 456  * @sig: Signature to test against
 457  * @out_size: if non-NULL, returns the size of the data part of the partition
 458  */
 459 loff_t nvram_find_partition(const char *name, int sig, int *out_size)
 460 {
 461         struct nvram_partition *p;
 462
 463         list_for_each_entry(p, &nvram_partitions, partition) {
 464                 if (p->header.signature == sig &&
 465                     (!name || !strncmp(p->header.name, name, 12))) {
 466                         if (out_size)
 467                                 *out_size = (p->header.length - 1) *
 468                                         NVRAM_BLOCK_LEN;
 469                         return p->index + NVRAM_HEADER_LEN;
 470                 }
 471         }
 472         return 0;
 473 }
 474
 475 int __init nvram_scan_partitions(void)
 476 {
 477         loff_t cur_index = 0;
 478         struct nvram_header phead;
 479         struct nvram_partition * tmp_part;
 480         unsigned char c_sum;
 481         char * header;
 482         int total_size;
 483         int err;
 484
 485         if (ppc_md.nvram_size == NULL || ppc_md.nvram_size() <= 0)
 486                 return -ENODEV;
 487         total_size = ppc_md.nvram_size();
 488
 489         header = kmalloc(NVRAM_HEADER_LEN, GFP_KERNEL);
 490         if (!header) {
 491                 printk(KERN_ERR "nvram_scan_partitions: Failed kmalloc\n");
 492                 return -ENOMEM;
 493         }
 494
 495         while (cur_index < total_size) {
 496
 497                 err = ppc_md.nvram_read(header, NVRAM_HEADER_LEN, &cur_index);
 498                 if (err != NVRAM_HEADER_LEN) {
 499                         printk(KERN_ERR "nvram_scan_partitions: Error parsing "
 500                                "nvram partitions\n");
 501                         goto out;
 502                 }
 503
 504                 cur_index -= NVRAM_HEADER_LEN; /* nvram_read will advance us */
 505
 506                 memcpy(&phead, header, NVRAM_HEADER_LEN);
 507
 508                 err = 0;
 509                 c_sum = nvram_checksum(&phead);
 510                 if (c_sum != phead.checksum) {
 511                         printk(KERN_WARNING "WARNING: nvram partition checksum"
 512                                " was %02x, should be %02x!\n",
 513                                phead.checksum, c_sum);
 514                         printk(KERN_WARNING "Terminating nvram partition scan\n");
 515                         goto out;
 516                 }
 517                 if (!phead.length) {
 518                         printk(KERN_WARNING "WARNING: nvram corruption "
 519                                "detected: 0-length partition\n");
 520                         goto out;
 521                 }
 522                 tmp_part = kmalloc(sizeof(struct nvram_partition), GFP_KERNEL);
 523                 err = -ENOMEM;
 524                 if (!tmp_part) {
 525                         printk(KERN_ERR "nvram_scan_partitions: kmalloc failed\n");
 526                         goto out;
 527                 }
 528
 529                 memcpy(&tmp_part->header, &phead, NVRAM_HEADER_LEN);
 530                 tmp_part->index = cur_index;
 531                 list_add_tail(&tmp_part->partition, &nvram_partitions);
 532
 533                 cur_index += phead.length * NVRAM_BLOCK_LEN;
 534         }
 535         err = 0;
 536
 537 #ifdef DEBUG_NVRAM
 538         nvram_print_partitions("NVRAM Partitions");
 539 #endif
 540
 541  out:
 542         kfree(header);
 543         return err;
 544 }
 545
 546 static int __init nvram_init(void)
 547 {
 548         int rc;
 549
 550         BUILD_BUG_ON(NVRAM_BLOCK_LEN != 16);
 551
 552         if (ppc_md.nvram_size == NULL || ppc_md.nvram_size() <= 0)
 553                 return  -ENODEV;
 554
 555         rc = misc_register(&nvram_dev);
 556         if (rc != 0) {
 557                 printk(KERN_ERR "nvram_init: failed to register device\n");
 558                 return rc;
 559         }
 560
 561         return rc;
 562 }
 563
 564 void __exit nvram_cleanup(void)
 565 {
 566         misc_deregister( &nvram_dev );
 567 }
 568
 569 module_init(nvram_init);
 570 module_exit(nvram_cleanup);
 571 MODULE_LICENSE("GPL");