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         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 long dev_nvram_ioctl(struct file *file, unsigned int cmd,
 154                             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 const 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         .unlocked_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 __init nvram_print_partitions(char * label)
 199 {
 200         struct nvram_partition * tmp_part;
 201
 202         printk(KERN_WARNING "--------%s---------\n", label);
 203         printk(KERN_WARNING "indx\t\tsig\tchks\tlen\tname\n");
 204         list_for_each_entry(tmp_part, &nvram_partitions, partition) {
 205                 printk(KERN_WARNING "%4d    \t%02x\t%02x\t%d\t%12s\n",
 206                        tmp_part->index, tmp_part->header.signature,
 207                        tmp_part->header.checksum, tmp_part->header.length,
 208                        tmp_part->header.name);
 209         }
 210 }
 211 #endif
 212
 213
 214 static int __init nvram_write_header(struct nvram_partition * part)
 215 {
 216         loff_t tmp_index;
 217         int rc;
 218
 219         tmp_index = part->index;
 220         rc = ppc_md.nvram_write((char *)&part->header, NVRAM_HEADER_LEN, &tmp_index);
 221
 222         return rc;
 223 }
 224
 225
 226 static unsigned char __init nvram_checksum(struct nvram_header *p)
 227 {
 228         unsigned int c_sum, c_sum2;
 229         unsigned short *sp = (unsigned short *)p->name; /* assume 6 shorts */
 230         c_sum = p->signature + p->length + sp[0] + sp[1] + sp[2] + sp[3] + sp[4] + sp[5];
 231
 232         /* The sum may have spilled into the 3rd byte.  Fold it back. */
 233         c_sum = ((c_sum & 0xffff) + (c_sum >> 16)) & 0xffff;
 234         /* The sum cannot exceed 2 bytes.  Fold it into a checksum */
 235         c_sum2 = (c_sum >> 8) + (c_sum << 8);
 236         c_sum = ((c_sum + c_sum2) >> 8) & 0xff;
 237         return c_sum;
 238 }
 239
 240 /*
 241  * Per the criteria passed via nvram_remove_partition(), should this
 242  * partition be removed?  1=remove, 0=keep
 243  */
 244 static int nvram_can_remove_partition(struct nvram_partition *part,
 245                 const char *name, int sig, const char *exceptions[])
 246 {
 247         if (part->header.signature != sig)
 248                 return 0;
 249         if (name) {
 250                 if (strncmp(name, part->header.name, 12))
 251                         return 0;
 252         } else if (exceptions) {
 253                 const char **except;
 254                 for (except = exceptions; *except; except++) {
 255                         if (!strncmp(*except, part->header.name, 12))
 256                                 return 0;
 257                 }
 258         }
 259         return 1;
 260 }
 261
 262 /**
 263  * nvram_remove_partition - Remove one or more partitions in nvram
 264  * @name: name of the partition to remove, or NULL for a
 265  *        signature only match
 266  * @sig: signature of the partition(s) to remove
 267  * @exceptions: When removing all partitions with a matching signature,
 268  *        leave these alone.
 269  */
 270
 271 int __init nvram_remove_partition(const char *name, int sig,
 272                                                 const char *exceptions[])
 273 {
 274         struct nvram_partition *part, *prev, *tmp;
 275         int rc;
 276
 277         list_for_each_entry(part, &nvram_partitions, partition) {
 278                 if (!nvram_can_remove_partition(part, name, sig, exceptions))
 279                         continue;
 280
 281                 /* Make partition a free partition */
 282                 part->header.signature = NVRAM_SIG_FREE;
 283                 strncpy(part->header.name, "wwwwwwwwwwww", 12);
 284                 part->header.checksum = nvram_checksum(&part->header);
 285                 rc = nvram_write_header(part);
 286                 if (rc <= 0) {
 287                         printk(KERN_ERR "nvram_remove_partition: nvram_write failed (%d)\n", rc);
 288                         return rc;
 289                 }
 290         }
 291
 292         /* Merge contiguous ones */
 293         prev = NULL;
 294         list_for_each_entry_safe(part, tmp, &nvram_partitions, partition) {
 295                 if (part->header.signature != NVRAM_SIG_FREE) {
 296                         prev = NULL;
 297                         continue;
 298                 }
 299                 if (prev) {
 300                         prev->header.length += part->header.length;
 301                         prev->header.checksum = nvram_checksum(&part->header);
 302                         rc = nvram_write_header(part);
 303                         if (rc <= 0) {
 304                                 printk(KERN_ERR "nvram_remove_partition: nvram_write failed (%d)\n", rc);
 305                                 return rc;
 306                         }
 307                         list_del(&part->partition);
 308                         kfree(part);
 309                 } else
 310                         prev = part;
 311         }
 312
 313         return 0;
 314 }
 315
 316 /**
 317  * nvram_create_partition - Create a partition in nvram
 318  * @name: name of the partition to create
 319  * @sig: signature of the partition to create
 320  * @req_size: size of data to allocate in bytes
 321  * @min_size: minimum acceptable size (0 means req_size)
 322  *
 323  * Returns a negative error code or a positive nvram index
 324  * of the beginning of the data area of the newly created
 325  * partition. If you provided a min_size smaller than req_size
 326  * you need to query for the actual size yourself after the
 327  * call using nvram_partition_get_size().
 328  */
 329 loff_t __init nvram_create_partition(const char *name, int sig,
 330                                      int req_size, int min_size)
 331 {
 332         struct nvram_partition *part;
 333         struct nvram_partition *new_part;
 334         struct nvram_partition *free_part = NULL;
 335         static char nv_init_vals[16];
 336         loff_t tmp_index;
 337         long size = 0;
 338         int rc;
 339
 340         /* Convert sizes from bytes to blocks */
 341         req_size = _ALIGN_UP(req_size, NVRAM_BLOCK_LEN) / NVRAM_BLOCK_LEN;
 342         min_size = _ALIGN_UP(min_size, NVRAM_BLOCK_LEN) / NVRAM_BLOCK_LEN;
 343
 344         /* If no minimum size specified, make it the same as the
 345          * requested size
 346          */
 347         if (min_size == 0)
 348                 min_size = req_size;
 349         if (min_size > req_size)
 350                 return -EINVAL;
 351
 352         /* Now add one block to each for the header */
 353         req_size += 1;
 354         min_size += 1;
 355
 356         /* Find a free partition that will give us the maximum needed size
 357            If can't find one that will give us the minimum size needed */
 358         list_for_each_entry(part, &nvram_partitions, partition) {
 359                 if (part->header.signature != NVRAM_SIG_FREE)
 360                         continue;
 361
 362                 if (part->header.length >= req_size) {
 363                         size = req_size;
 364                         free_part = part;
 365                         break;
 366                 }
 367                 if (part->header.length > size &&
 368                     part->header.length >= min_size) {
 369                         size = part->header.length;
 370                         free_part = part;
 371                 }
 372         }
 373         if (!size)
 374                 return -ENOSPC;
 375
 376         /* Create our OS partition */
 377         new_part = kmalloc(sizeof(*new_part), GFP_KERNEL);
 378         if (!new_part) {
 379                 pr_err("nvram_create_os_partition: kmalloc failed\n");
 380                 return -ENOMEM;
 381         }
 382
 383         new_part->index = free_part->index;
 384         new_part->header.signature = sig;
 385         new_part->header.length = size;
 386         strncpy(new_part->header.name, name, 12);
 387         new_part->header.checksum = nvram_checksum(&new_part->header);
 388
 389         rc = nvram_write_header(new_part);
 390         if (rc <= 0) {
 391                 pr_err("nvram_create_os_partition: nvram_write_header "
 392                        "failed (%d)\n", rc);
 393                 return rc;
 394         }
 395         list_add_tail(&new_part->partition, &free_part->partition);
 396
 397         /* Adjust or remove the partition we stole the space from */
 398         if (free_part->header.length > size) {
 399                 free_part->index += size * NVRAM_BLOCK_LEN;
 400                 free_part->header.length -= size;
 401                 free_part->header.checksum = nvram_checksum(&free_part->header);
 402                 rc = nvram_write_header(free_part);
 403                 if (rc <= 0) {
 404                         pr_err("nvram_create_os_partition: nvram_write_header "
 405                                "failed (%d)\n", rc);
 406                         return rc;
 407                 }
 408         } else {
 409                 list_del(&free_part->partition);
 410                 kfree(free_part);
 411         }
 412
 413         /* Clear the new partition */
 414         for (tmp_index = new_part->index + NVRAM_HEADER_LEN;
 415              tmp_index <  ((size - 1) * NVRAM_BLOCK_LEN);
 416              tmp_index += NVRAM_BLOCK_LEN) {
 417                 rc = ppc_md.nvram_write(nv_init_vals, NVRAM_BLOCK_LEN, &tmp_index);
 418                 if (rc <= 0) {
 419                         pr_err("nvram_create_partition: nvram_write failed (%d)\n", rc);
 420                         return rc;
 421                 }
 422         }
 423
 424         return new_part->index + NVRAM_HEADER_LEN;
 425 }
 426
 427 /**
 428  * nvram_get_partition_size - Get the data size of an nvram partition
 429  * @data_index: This is the offset of the start of the data of
 430  *              the partition. The same value that is returned by
 431  *              nvram_create_partition().
 432  */
 433 int nvram_get_partition_size(loff_t data_index)
 434 {
 435         struct nvram_partition *part;
 436
 437         list_for_each_entry(part, &nvram_partitions, partition) {
 438                 if (part->index + NVRAM_HEADER_LEN == data_index)
 439                         return (part->header.length - 1) * NVRAM_BLOCK_LEN;
 440         }
 441         return -1;
 442 }
 443
 444
 445 /**
 446  * nvram_find_partition - Find an nvram partition by signature and name
 447  * @name: Name of the partition or NULL for any name
 448  * @sig: Signature to test against
 449  * @out_size: if non-NULL, returns the size of the data part of the partition
 450  */
 451 loff_t nvram_find_partition(const char *name, int sig, int *out_size)
 452 {
 453         struct nvram_partition *p;
 454
 455         list_for_each_entry(p, &nvram_partitions, partition) {
 456                 if (p->header.signature == sig &&
 457                     (!name || !strncmp(p->header.name, name, 12))) {
 458                         if (out_size)
 459                                 *out_size = (p->header.length - 1) *
 460                                         NVRAM_BLOCK_LEN;
 461                         return p->index + NVRAM_HEADER_LEN;
 462                 }
 463         }
 464         return 0;
 465 }
 466
 467 int __init nvram_scan_partitions(void)
 468 {
 469         loff_t cur_index = 0;
 470         struct nvram_header phead;
 471         struct nvram_partition * tmp_part;
 472         unsigned char c_sum;
 473         char * header;
 474         int total_size;
 475         int err;
 476
 477         if (ppc_md.nvram_size == NULL || ppc_md.nvram_size() <= 0)
 478                 return -ENODEV;
 479         total_size = ppc_md.nvram_size();
 480
 481         header = kmalloc(NVRAM_HEADER_LEN, GFP_KERNEL);
 482         if (!header) {
 483                 printk(KERN_ERR "nvram_scan_partitions: Failed kmalloc\n");
 484                 return -ENOMEM;
 485         }
 486
 487         while (cur_index < total_size) {
 488
 489                 err = ppc_md.nvram_read(header, NVRAM_HEADER_LEN, &cur_index);
 490                 if (err != NVRAM_HEADER_LEN) {
 491                         printk(KERN_ERR "nvram_scan_partitions: Error parsing "
 492                                "nvram partitions\n");
 493                         goto out;
 494                 }
 495
 496                 cur_index -= NVRAM_HEADER_LEN; /* nvram_read will advance us */
 497
 498                 memcpy(&phead, header, NVRAM_HEADER_LEN);
 499
 500                 err = 0;
 501                 c_sum = nvram_checksum(&phead);
 502                 if (c_sum != phead.checksum) {
 503                         printk(KERN_WARNING "WARNING: nvram partition checksum"
 504                                " was %02x, should be %02x!\n",
 505                                phead.checksum, c_sum);
 506                         printk(KERN_WARNING "Terminating nvram partition scan\n");
 507                         goto out;
 508                 }
 509                 if (!phead.length) {
 510                         printk(KERN_WARNING "WARNING: nvram corruption "
 511                                "detected: 0-length partition\n");
 512                         goto out;
 513                 }
 514                 tmp_part = (struct nvram_partition *)
 515                         kmalloc(sizeof(struct nvram_partition), GFP_KERNEL);
 516                 err = -ENOMEM;
 517                 if (!tmp_part) {
 518                         printk(KERN_ERR "nvram_scan_partitions: kmalloc failed\n");
 519                         goto out;
 520                 }
 521
 522                 memcpy(&tmp_part->header, &phead, NVRAM_HEADER_LEN);
 523                 tmp_part->index = cur_index;
 524                 list_add_tail(&tmp_part->partition, &nvram_partitions);
 525
 526                 cur_index += phead.length * NVRAM_BLOCK_LEN;
 527         }
 528         err = 0;
 529
 530 #ifdef DEBUG_NVRAM
 531         nvram_print_partitions("NVRAM Partitions");
 532 #endif
 533
 534  out:
 535         kfree(header);
 536         return err;
 537 }
 538
 539 static int __init nvram_init(void)
 540 {
 541         int rc;
 542
 543         BUILD_BUG_ON(NVRAM_BLOCK_LEN != 16);
 544
 545         if (ppc_md.nvram_size == NULL || ppc_md.nvram_size() <= 0)
 546                 return  -ENODEV;
 547
 548         rc = misc_register(&nvram_dev);
 549         if (rc != 0) {
 550                 printk(KERN_ERR "nvram_init: failed to register device\n");
 551                 return rc;
 552         }
 553
 554         return rc;
 555 }
 556
 557 void __exit nvram_cleanup(void)
 558 {
 559         misc_deregister( &nvram_dev );
 560 }
 561
 562 module_init(nvram_init);
 563 module_exit(nvram_cleanup);
 564 MODULE_LICENSE("GPL");