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%12.12s\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         struct nvram_header phead;
 227
 228         memcpy(&phead, &part->header, NVRAM_HEADER_LEN);
 229         phead.length = cpu_to_be16(phead.length);
 230
 231         tmp_index = part->index;
 232         rc = ppc_md.nvram_write((char *)&phead, NVRAM_HEADER_LEN, &tmp_index);
 233
 234         return rc;
 235 }
 236
 237
 238 static unsigned char __init nvram_checksum(struct nvram_header *p)
 239 {
 240         unsigned int c_sum, c_sum2;
 241         unsigned short *sp = (unsigned short *)p->name; /* assume 6 shorts */
 242         c_sum = p->signature + p->length + sp[0] + sp[1] + sp[2] + sp[3] + sp[4] + sp[5];
 243
 244         /* The sum may have spilled into the 3rd byte.  Fold it back. */
 245         c_sum = ((c_sum & 0xffff) + (c_sum >> 16)) & 0xffff;
 246         /* The sum cannot exceed 2 bytes.  Fold it into a checksum */
 247         c_sum2 = (c_sum >> 8) + (c_sum << 8);
 248         c_sum = ((c_sum + c_sum2) >> 8) & 0xff;
 249         return c_sum;
 250 }
 251
 252 /*
 253  * Per the criteria passed via nvram_remove_partition(), should this
 254  * partition be removed?  1=remove, 0=keep
 255  */
 256 static int nvram_can_remove_partition(struct nvram_partition *part,
 257                 const char *name, int sig, const char *exceptions[])
 258 {
 259         if (part->header.signature != sig)
 260                 return 0;
 261         if (name) {
 262                 if (strncmp(name, part->header.name, 12))
 263                         return 0;
 264         } else if (exceptions) {
 265                 const char **except;
 266                 for (except = exceptions; *except; except++) {
 267                         if (!strncmp(*except, part->header.name, 12))
 268                                 return 0;
 269                 }
 270         }
 271         return 1;
 272 }
 273
 274 /**
 275  * nvram_remove_partition - Remove one or more partitions in nvram
 276  * @name: name of the partition to remove, or NULL for a
 277  *        signature only match
 278  * @sig: signature of the partition(s) to remove
 279  * @exceptions: When removing all partitions with a matching signature,
 280  *        leave these alone.
 281  */
 282
 283 int __init nvram_remove_partition(const char *name, int sig,
 284                                                 const char *exceptions[])
 285 {
 286         struct nvram_partition *part, *prev, *tmp;
 287         int rc;
 288
 289         list_for_each_entry(part, &nvram_partitions, partition) {
 290                 if (!nvram_can_remove_partition(part, name, sig, exceptions))
 291                         continue;
 292
 293                 /* Make partition a free partition */
 294                 part->header.signature = NVRAM_SIG_FREE;
 295                 strncpy(part->header.name, "wwwwwwwwwwww", 12);
 296                 part->header.checksum = nvram_checksum(&part->header);
 297                 rc = nvram_write_header(part);
 298                 if (rc <= 0) {
 299                         printk(KERN_ERR "nvram_remove_partition: nvram_write failed (%d)\n", rc);
 300                         return rc;
 301                 }
 302         }
 303
 304         /* Merge contiguous ones */
 305         prev = NULL;
 306         list_for_each_entry_safe(part, tmp, &nvram_partitions, partition) {
 307                 if (part->header.signature != NVRAM_SIG_FREE) {
 308                         prev = NULL;
 309                         continue;
 310                 }
 311                 if (prev) {
 312                         prev->header.length += part->header.length;
 313                         prev->header.checksum = nvram_checksum(&part->header);
 314                         rc = nvram_write_header(part);
 315                         if (rc <= 0) {
 316                                 printk(KERN_ERR "nvram_remove_partition: nvram_write failed (%d)\n", rc);
 317                                 return rc;
 318                         }
 319                         list_del(&part->partition);
 320                         kfree(part);
 321                 } else
 322                         prev = part;
 323         }
 324
 325         return 0;
 326 }
 327
 328 /**
 329  * nvram_create_partition - Create a partition in nvram
 330  * @name: name of the partition to create
 331  * @sig: signature of the partition to create
 332  * @req_size: size of data to allocate in bytes
 333  * @min_size: minimum acceptable size (0 means req_size)
 334  *
 335  * Returns a negative error code or a positive nvram index
 336  * of the beginning of the data area of the newly created
 337  * partition. If you provided a min_size smaller than req_size
 338  * you need to query for the actual size yourself after the
 339  * call using nvram_partition_get_size().
 340  */
 341 loff_t __init nvram_create_partition(const char *name, int sig,
 342                                      int req_size, int min_size)
 343 {
 344         struct nvram_partition *part;
 345         struct nvram_partition *new_part;
 346         struct nvram_partition *free_part = NULL;
 347         static char nv_init_vals[16];
 348         loff_t tmp_index;
 349         long size = 0;
 350         int rc;
 351
 352         /* Convert sizes from bytes to blocks */
 353         req_size = _ALIGN_UP(req_size, NVRAM_BLOCK_LEN) / NVRAM_BLOCK_LEN;
 354         min_size = _ALIGN_UP(min_size, NVRAM_BLOCK_LEN) / NVRAM_BLOCK_LEN;
 355
 356         /* If no minimum size specified, make it the same as the
 357          * requested size
 358          */
 359         if (min_size == 0)
 360                 min_size = req_size;
 361         if (min_size > req_size)
 362                 return -EINVAL;
 363
 364         /* Now add one block to each for the header */
 365         req_size += 1;
 366         min_size += 1;
 367
 368         /* Find a free partition that will give us the maximum needed size
 369            If can't find one that will give us the minimum size needed */
 370         list_for_each_entry(part, &nvram_partitions, partition) {
 371                 if (part->header.signature != NVRAM_SIG_FREE)
 372                         continue;
 373
 374                 if (part->header.length >= req_size) {
 375                         size = req_size;
 376                         free_part = part;
 377                         break;
 378                 }
 379                 if (part->header.length > size &&
 380                     part->header.length >= min_size) {
 381                         size = part->header.length;
 382                         free_part = part;
 383                 }
 384         }
 385         if (!size)
 386                 return -ENOSPC;
 387
 388         /* Create our OS partition */
 389         new_part = kmalloc(sizeof(*new_part), GFP_KERNEL);
 390         if (!new_part) {
 391                 pr_err("nvram_create_os_partition: kmalloc failed\n");
 392                 return -ENOMEM;
 393         }
 394
 395         new_part->index = free_part->index;
 396         new_part->header.signature = sig;
 397         new_part->header.length = size;
 398         strncpy(new_part->header.name, name, 12);
 399         new_part->header.checksum = nvram_checksum(&new_part->header);
 400
 401         rc = nvram_write_header(new_part);
 402         if (rc <= 0) {
 403                 pr_err("nvram_create_os_partition: nvram_write_header "
 404                        "failed (%d)\n", rc);
 405                 return rc;
 406         }
 407         list_add_tail(&new_part->partition, &free_part->partition);
 408
 409         /* Adjust or remove the partition we stole the space from */
 410         if (free_part->header.length > size) {
 411                 free_part->index += size * NVRAM_BLOCK_LEN;
 412                 free_part->header.length -= size;
 413                 free_part->header.checksum = nvram_checksum(&free_part->header);
 414                 rc = nvram_write_header(free_part);
 415                 if (rc <= 0) {
 416                         pr_err("nvram_create_os_partition: nvram_write_header "
 417                                "failed (%d)\n", rc);
 418                         return rc;
 419                 }
 420         } else {
 421                 list_del(&free_part->partition);
 422                 kfree(free_part);
 423         }
 424
 425         /* Clear the new partition */
 426         for (tmp_index = new_part->index + NVRAM_HEADER_LEN;
 427              tmp_index <  ((size - 1) * NVRAM_BLOCK_LEN);
 428              tmp_index += NVRAM_BLOCK_LEN) {
 429                 rc = ppc_md.nvram_write(nv_init_vals, NVRAM_BLOCK_LEN, &tmp_index);
 430                 if (rc <= 0) {
 431                         pr_err("nvram_create_partition: nvram_write failed (%d)\n", rc);
 432                         return rc;
 433                 }
 434         }
 435
 436         return new_part->index + NVRAM_HEADER_LEN;
 437 }
 438
 439 /**
 440  * nvram_get_partition_size - Get the data size of an nvram partition
 441  * @data_index: This is the offset of the start of the data of
 442  *              the partition. The same value that is returned by
 443  *              nvram_create_partition().
 444  */
 445 int nvram_get_partition_size(loff_t data_index)
 446 {
 447         struct nvram_partition *part;
 448
 449         list_for_each_entry(part, &nvram_partitions, partition) {
 450                 if (part->index + NVRAM_HEADER_LEN == data_index)
 451                         return (part->header.length - 1) * NVRAM_BLOCK_LEN;
 452         }
 453         return -1;
 454 }
 455
 456
 457 /**
 458  * nvram_find_partition - Find an nvram partition by signature and name
 459  * @name: Name of the partition or NULL for any name
 460  * @sig: Signature to test against
 461  * @out_size: if non-NULL, returns the size of the data part of the partition
 462  */
 463 loff_t nvram_find_partition(const char *name, int sig, int *out_size)
 464 {
 465         struct nvram_partition *p;
 466
 467         list_for_each_entry(p, &nvram_partitions, partition) {
 468                 if (p->header.signature == sig &&
 469                     (!name || !strncmp(p->header.name, name, 12))) {
 470                         if (out_size)
 471                                 *out_size = (p->header.length - 1) *
 472                                         NVRAM_BLOCK_LEN;
 473                         return p->index + NVRAM_HEADER_LEN;
 474                 }
 475         }
 476         return 0;
 477 }
 478
 479 int __init nvram_scan_partitions(void)
 480 {
 481         loff_t cur_index = 0;
 482         struct nvram_header phead;
 483         struct nvram_partition * tmp_part;
 484         unsigned char c_sum;
 485         char * header;
 486         int total_size;
 487         int err;
 488
 489         if (ppc_md.nvram_size == NULL || ppc_md.nvram_size() <= 0)
 490                 return -ENODEV;
 491         total_size = ppc_md.nvram_size();
 492
 493         header = kmalloc(NVRAM_HEADER_LEN, GFP_KERNEL);
 494         if (!header) {
 495                 printk(KERN_ERR "nvram_scan_partitions: Failed kmalloc\n");
 496                 return -ENOMEM;
 497         }
 498
 499         while (cur_index < total_size) {
 500
 501                 err = ppc_md.nvram_read(header, NVRAM_HEADER_LEN, &cur_index);
 502                 if (err != NVRAM_HEADER_LEN) {
 503                         printk(KERN_ERR "nvram_scan_partitions: Error parsing "
 504                                "nvram partitions\n");
 505                         goto out;
 506                 }
 507
 508                 cur_index -= NVRAM_HEADER_LEN; /* nvram_read will advance us */
 509
 510                 memcpy(&phead, header, NVRAM_HEADER_LEN);
 511
 512                 phead.length = be16_to_cpu(phead.length);
 513
 514                 err = 0;
 515                 c_sum = nvram_checksum(&phead);
 516                 if (c_sum != phead.checksum) {
 517                         printk(KERN_WARNING "WARNING: nvram partition checksum"
 518                                " was %02x, should be %02x!\n",
 519                                phead.checksum, c_sum);
 520                         printk(KERN_WARNING "Terminating nvram partition scan\n");
 521                         goto out;
 522                 }
 523                 if (!phead.length) {
 524                         printk(KERN_WARNING "WARNING: nvram corruption "
 525                                "detected: 0-length partition\n");
 526                         goto out;
 527                 }
 528                 tmp_part = kmalloc(sizeof(struct nvram_partition), GFP_KERNEL);
 529                 err = -ENOMEM;
 530                 if (!tmp_part) {
 531                         printk(KERN_ERR "nvram_scan_partitions: kmalloc failed\n");
 532                         goto out;
 533                 }
 534
 535                 memcpy(&tmp_part->header, &phead, NVRAM_HEADER_LEN);
 536                 tmp_part->index = cur_index;
 537                 list_add_tail(&tmp_part->partition, &nvram_partitions);
 538
 539                 cur_index += phead.length * NVRAM_BLOCK_LEN;
 540         }
 541         err = 0;
 542
 543 #ifdef DEBUG_NVRAM
 544         nvram_print_partitions("NVRAM Partitions");
 545 #endif
 546
 547  out:
 548         kfree(header);
 549         return err;
 550 }
 551
 552 static int __init nvram_init(void)
 553 {
 554         int rc;
 555
 556         BUILD_BUG_ON(NVRAM_BLOCK_LEN != 16);
 557
 558         if (ppc_md.nvram_size == NULL || ppc_md.nvram_size() <= 0)
 559                 return  -ENODEV;
 560
 561         rc = misc_register(&nvram_dev);
 562         if (rc != 0) {
 563                 printk(KERN_ERR "nvram_init: failed to register device\n");
 564                 return rc;
 565         }
 566
 567         return rc;
 568 }
 569
 570 void __exit nvram_cleanup(void)
 571 {
 572         misc_deregister( &nvram_dev );
 573 }
 574
 575 module_init(nvram_init);
 576 module_exit(nvram_cleanup);
 577 MODULE_LICENSE("GPL");