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         char name[12];
  46 };
  47
  48 struct nvram_partition {
  49         struct list_head partition;
  50         struct nvram_header header;
  51         unsigned int index;
  52 };
  53
  54 static struct nvram_partition * nvram_part;
  55
  56 static loff_t dev_nvram_llseek(struct file *file, loff_t offset, int origin)
  57 {
  58         int size;
  59
  60         if (ppc_md.nvram_size == NULL)
  61                 return -ENODEV;
  62         size = ppc_md.nvram_size();
  63
  64         switch (origin) {
  65         case 1:
  66                 offset += file->f_pos;
  67                 break;
  68         case 2:
  69                 offset += size;
  70                 break;
  71         }
  72         if (offset < 0)
  73                 return -EINVAL;
  74         file->f_pos = offset;
  75         return file->f_pos;
  76 }
  77
  78
  79 static ssize_t dev_nvram_read(struct file *file, char __user *buf,
  80                           size_t count, loff_t *ppos)
  81 {
  82         ssize_t ret;
  83         char *tmp = NULL;
  84         ssize_t size;
  85
  86         ret = -ENODEV;
  87         if (!ppc_md.nvram_size)
  88                 goto out;
  89
  90         ret = 0;
  91         size = ppc_md.nvram_size();
  92         if (*ppos >= size || size < 0)
  93                 goto out;
  94
  95         count = min_t(size_t, count, size - *ppos);
  96         count = min(count, PAGE_SIZE);
  97
  98         ret = -ENOMEM;
  99         tmp = kmalloc(count, GFP_KERNEL);
 100         if (!tmp)
 101                 goto out;
 102
 103         ret = ppc_md.nvram_read(tmp, count, ppos);
 104         if (ret <= 0)
 105                 goto out;
 106
 107         if (copy_to_user(buf, tmp, ret))
 108                 ret = -EFAULT;
 109
 110 out:
 111         kfree(tmp);
 112         return ret;
 113
 114 }
 115
 116 static ssize_t dev_nvram_write(struct file *file, const char __user *buf,
 117                           size_t count, loff_t *ppos)
 118 {
 119         ssize_t ret;
 120         char *tmp = NULL;
 121         ssize_t size;
 122
 123         ret = -ENODEV;
 124         if (!ppc_md.nvram_size)
 125                 goto out;
 126
 127         ret = 0;
 128         size = ppc_md.nvram_size();
 129         if (*ppos >= size || size < 0)
 130                 goto out;
 131
 132         count = min_t(size_t, count, size - *ppos);
 133         count = min(count, PAGE_SIZE);
 134
 135         ret = -ENOMEM;
 136         tmp = kmalloc(count, GFP_KERNEL);
 137         if (!tmp)
 138                 goto out;
 139
 140         ret = -EFAULT;
 141         if (copy_from_user(tmp, buf, count))
 142                 goto out;
 143
 144         ret = ppc_md.nvram_write(tmp, count, ppos);
 145
 146 out:
 147         kfree(tmp);
 148         return ret;
 149
 150 }
 151
 152 static long dev_nvram_ioctl(struct file *file, unsigned int cmd,
 153                             unsigned long arg)
 154 {
 155         switch(cmd) {
 156 #ifdef CONFIG_PPC_PMAC
 157         case OBSOLETE_PMAC_NVRAM_GET_OFFSET:
 158                 printk(KERN_WARNING "nvram: Using obsolete PMAC_NVRAM_GET_OFFSET ioctl\n");
 159         case IOC_NVRAM_GET_OFFSET: {
 160                 int part, offset;
 161
 162                 if (!machine_is(powermac))
 163                         return -EINVAL;
 164                 if (copy_from_user(&part, (void __user*)arg, sizeof(part)) != 0)
 165                         return -EFAULT;
 166                 if (part < pmac_nvram_OF || part > pmac_nvram_NR)
 167                         return -EINVAL;
 168                 offset = pmac_get_partition(part);
 169                 if (offset < 0)
 170                         return offset;
 171                 if (copy_to_user((void __user*)arg, &offset, sizeof(offset)) != 0)
 172                         return -EFAULT;
 173                 return 0;
 174         }
 175 #endif /* CONFIG_PPC_PMAC */
 176         default:
 177                 return -EINVAL;
 178         }
 179 }
 180
 181 const struct file_operations nvram_fops = {
 182         .owner          = THIS_MODULE,
 183         .llseek         = dev_nvram_llseek,
 184         .read           = dev_nvram_read,
 185         .write          = dev_nvram_write,
 186         .unlocked_ioctl = dev_nvram_ioctl,
 187 };
 188
 189 static struct miscdevice nvram_dev = {
 190         NVRAM_MINOR,
 191         "nvram",
 192         &nvram_fops
 193 };
 194
 195
 196 #ifdef DEBUG_NVRAM
 197 static void __init nvram_print_partitions(char * label)
 198 {
 199         struct list_head * p;
 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(p, &nvram_part->partition) {
 205                 tmp_part = list_entry(p, struct nvram_partition, partition);
 206                 printk(KERN_WARNING "%4d    \t%02x\t%02x\t%d\t%s\n",
 207                        tmp_part->index, tmp_part->header.signature,
 208                        tmp_part->header.checksum, tmp_part->header.length,
 209                        tmp_part->header.name);
 210         }
 211 }
 212 #endif
 213
 214
 215 static int __init nvram_write_header(struct nvram_partition * part)
 216 {
 217         loff_t tmp_index;
 218         int rc;
 219
 220         tmp_index = part->index;
 221         rc = ppc_md.nvram_write((char *)&part->header, NVRAM_HEADER_LEN, &tmp_index);
 222
 223         return rc;
 224 }
 225
 226
 227 static unsigned char __init nvram_checksum(struct nvram_header *p)
 228 {
 229         unsigned int c_sum, c_sum2;
 230         unsigned short *sp = (unsigned short *)p->name; /* assume 6 shorts */
 231         c_sum = p->signature + p->length + sp[0] + sp[1] + sp[2] + sp[3] + sp[4] + sp[5];
 232
 233         /* The sum may have spilled into the 3rd byte.  Fold it back. */
 234         c_sum = ((c_sum & 0xffff) + (c_sum >> 16)) & 0xffff;
 235         /* The sum cannot exceed 2 bytes.  Fold it into a checksum */
 236         c_sum2 = (c_sum >> 8) + (c_sum << 8);
 237         c_sum = ((c_sum + c_sum2) >> 8) & 0xff;
 238         return c_sum;
 239 }
 240
 241 /**
 242  * nvram_remove_partition - Remove one or more partitions in nvram
 243  * @name: name of the partition to remove, or NULL for a
 244  *        signature only match
 245  * @sig: signature of the partition(s) to remove
 246  */
 247
 248 int __init nvram_remove_partition(const char *name, int sig)
 249 {
 250         struct nvram_partition *part, *prev, *tmp;
 251         int rc;
 252
 253         list_for_each_entry(part, &nvram_part->partition, partition) {
 254                 if (part->header.signature != sig)
 255                         continue;
 256                 if (name && strncmp(name, part->header.name, 12))
 257                         continue;
 258
 259                 /* Make partition a free partition */
 260                 part->header.signature = NVRAM_SIG_FREE;
 261                 sprintf(part->header.name, "wwwwwwwwwwww");
 262                 part->header.checksum = nvram_checksum(&part->header);
 263                 rc = nvram_write_header(part);
 264                 if (rc <= 0) {
 265                         printk(KERN_ERR "nvram_remove_partition: nvram_write failed (%d)\n", rc);
 266                         return rc;
 267                 }
 268         }
 269
 270         /* Merge contiguous ones */
 271         prev = NULL;
 272         list_for_each_entry_safe(part, tmp, &nvram_part->partition, partition) {
 273                 if (part->header.signature != NVRAM_SIG_FREE) {
 274                         prev = NULL;
 275                         continue;
 276                 }
 277                 if (prev) {
 278                         prev->header.length += part->header.length;
 279                         prev->header.checksum = nvram_checksum(&part->header);
 280                         rc = nvram_write_header(part);
 281                         if (rc <= 0) {
 282                                 printk(KERN_ERR "nvram_remove_partition: nvram_write failed (%d)\n", rc);
 283                                 return rc;
 284                         }
 285                         list_del(&part->partition);
 286                         kfree(part);
 287                 } else
 288                         prev = part;
 289         }
 290
 291         return 0;
 292 }
 293
 294 /**
 295  * nvram_create_partition - Create a partition in nvram
 296  * @name: name of the partition to create
 297  * @sig: signature of the partition to create
 298  * @req_size: size of data to allocate in bytes
 299  * @min_size: minimum acceptable size (0 means req_size)
 300  *
 301  * Returns a negative error code or a positive nvram index
 302  * of the beginning of the data area of the newly created
 303  * partition. If you provided a min_size smaller than req_size
 304  * you need to query for the actual size yourself after the
 305  * call using nvram_partition_get_size().
 306  */
 307 loff_t __init nvram_create_partition(const char *name, int sig,
 308                                      int req_size, int min_size)
 309 {
 310         struct nvram_partition *part;
 311         struct nvram_partition *new_part;
 312         struct nvram_partition *free_part = NULL;
 313         static char nv_init_vals[16];
 314         loff_t tmp_index;
 315         long size = 0;
 316         int rc;
 317
 318         /* Convert sizes from bytes to blocks */
 319         req_size = _ALIGN_UP(req_size, NVRAM_BLOCK_LEN) / NVRAM_BLOCK_LEN;
 320         min_size = _ALIGN_UP(min_size, NVRAM_BLOCK_LEN) / NVRAM_BLOCK_LEN;
 321
 322         /* If no minimum size specified, make it the same as the
 323          * requested size
 324          */
 325         if (min_size == 0)
 326                 min_size = req_size;
 327         if (min_size > req_size)
 328                 return -EINVAL;
 329
 330         /* Now add one block to each for the header */
 331         req_size += 1;
 332         min_size += 1;
 333
 334         /* Find a free partition that will give us the maximum needed size
 335            If can't find one that will give us the minimum size needed */
 336         list_for_each_entry(part, &nvram_part->partition, partition) {
 337                 if (part->header.signature != NVRAM_SIG_FREE)
 338                         continue;
 339
 340                 if (part->header.length >= req_size) {
 341                         size = req_size;
 342                         free_part = part;
 343                         break;
 344                 }
 345                 if (part->header.length > size &&
 346                     part->header.length >= min_size) {
 347                         size = part->header.length;
 348                         free_part = part;
 349                 }
 350         }
 351         if (!size)
 352                 return -ENOSPC;
 353
 354         /* Create our OS partition */
 355         new_part = kmalloc(sizeof(*new_part), GFP_KERNEL);
 356         if (!new_part) {
 357                 pr_err("nvram_create_os_partition: kmalloc failed\n");
 358                 return -ENOMEM;
 359         }
 360
 361         new_part->index = free_part->index;
 362         new_part->header.signature = sig;
 363         new_part->header.length = size;
 364         strncpy(new_part->header.name, name, 12);
 365         new_part->header.checksum = nvram_checksum(&new_part->header);
 366
 367         rc = nvram_write_header(new_part);
 368         if (rc <= 0) {
 369                 pr_err("nvram_create_os_partition: nvram_write_header "
 370                        "failed (%d)\n", rc);
 371                 return rc;
 372         }
 373         list_add_tail(&new_part->partition, &free_part->partition);
 374
 375         /* Adjust or remove the partition we stole the space from */
 376         if (free_part->header.length > size) {
 377                 free_part->index += size * NVRAM_BLOCK_LEN;
 378                 free_part->header.length -= size;
 379                 free_part->header.checksum = nvram_checksum(&free_part->header);
 380                 rc = nvram_write_header(free_part);
 381                 if (rc <= 0) {
 382                         pr_err("nvram_create_os_partition: nvram_write_header "
 383                                "failed (%d)\n", rc);
 384                         return rc;
 385                 }
 386         } else {
 387                 list_del(&free_part->partition);
 388                 kfree(free_part);
 389         }
 390
 391         /* Clear the new partition */
 392         for (tmp_index = new_part->index + NVRAM_HEADER_LEN;
 393              tmp_index <  ((size - 1) * NVRAM_BLOCK_LEN);
 394              tmp_index += NVRAM_BLOCK_LEN) {
 395                 rc = ppc_md.nvram_write(nv_init_vals, NVRAM_BLOCK_LEN, &tmp_index);
 396                 if (rc <= 0) {
 397                         pr_err("nvram_create_partition: nvram_write failed (%d)\n", rc);
 398                         return rc;
 399                 }
 400         }
 401
 402         return new_part->index + NVRAM_HEADER_LEN;
 403 }
 404
 405 /**
 406  * nvram_get_partition_size - Get the data size of an nvram partition
 407  * @data_index: This is the offset of the start of the data of
 408  *              the partition. The same value that is returned by
 409  *              nvram_create_partition().
 410  */
 411 int nvram_get_partition_size(loff_t data_index)
 412 {
 413         struct nvram_partition *part;
 414
 415         list_for_each_entry(part, &nvram_part->partition, partition) {
 416                 if (part->index + NVRAM_HEADER_LEN == data_index)
 417                         return (part->header.length - 1) * NVRAM_BLOCK_LEN;
 418         }
 419         return -1;
 420 }
 421
 422
 423 /**
 424  * nvram_find_partition - Find an nvram partition by signature and name
 425  * @name: Name of the partition or NULL for any name
 426  * @sig: Signature to test against
 427  * @out_size: if non-NULL, returns the size of the data part of the partition
 428  */
 429 loff_t nvram_find_partition(const char *name, int sig, int *out_size)
 430 {
 431         struct nvram_partition *p;
 432
 433         list_for_each_entry(p, &nvram_part->partition, partition) {
 434                 if (p->header.signature == sig &&
 435                     (!name || !strncmp(p->header.name, name, 12))) {
 436                         if (out_size)
 437                                 *out_size = (p->header.length - 1) *
 438                                         NVRAM_BLOCK_LEN;
 439                         return p->index + NVRAM_HEADER_LEN;
 440                 }
 441         }
 442         return 0;
 443 }
 444
 445 int __init nvram_scan_partitions(void)
 446 {
 447         loff_t cur_index = 0;
 448         struct nvram_header phead;
 449         struct nvram_partition * tmp_part;
 450         unsigned char c_sum;
 451         char * header;
 452         int total_size;
 453         int err;
 454
 455         /* Initialize our anchor for the nvram partition list */
 456         nvram_part = kmalloc(sizeof(struct nvram_partition), GFP_KERNEL);
 457         if (!nvram_part) {
 458                 printk(KERN_ERR "nvram_init: Failed kmalloc\n");
 459                 return -ENOMEM;
 460         }
 461         INIT_LIST_HEAD(&nvram_part->partition);
 462
 463         if (ppc_md.nvram_size == NULL || ppc_md.nvram_size() <= 0)
 464                 return -ENODEV;
 465         total_size = ppc_md.nvram_size();
 466
 467         header = kmalloc(NVRAM_HEADER_LEN, GFP_KERNEL);
 468         if (!header) {
 469                 printk(KERN_ERR "nvram_scan_partitions: Failed kmalloc\n");
 470                 return -ENOMEM;
 471         }
 472
 473         while (cur_index < total_size) {
 474
 475                 err = ppc_md.nvram_read(header, NVRAM_HEADER_LEN, &cur_index);
 476                 if (err != NVRAM_HEADER_LEN) {
 477                         printk(KERN_ERR "nvram_scan_partitions: Error parsing "
 478                                "nvram partitions\n");
 479                         goto out;
 480                 }
 481
 482                 cur_index -= NVRAM_HEADER_LEN; /* nvram_read will advance us */
 483
 484                 memcpy(&phead, header, NVRAM_HEADER_LEN);
 485
 486                 err = 0;
 487                 c_sum = nvram_checksum(&phead);
 488                 if (c_sum != phead.checksum) {
 489                         printk(KERN_WARNING "WARNING: nvram partition checksum"
 490                                " was %02x, should be %02x!\n",
 491                                phead.checksum, c_sum);
 492                         printk(KERN_WARNING "Terminating nvram partition scan\n");
 493                         goto out;
 494                 }
 495                 if (!phead.length) {
 496                         printk(KERN_WARNING "WARNING: nvram corruption "
 497                                "detected: 0-length partition\n");
 498                         goto out;
 499                 }
 500                 tmp_part = (struct nvram_partition *)
 501                         kmalloc(sizeof(struct nvram_partition), GFP_KERNEL);
 502                 err = -ENOMEM;
 503                 if (!tmp_part) {
 504                         printk(KERN_ERR "nvram_scan_partitions: kmalloc failed\n");
 505                         goto out;
 506                 }
 507
 508                 memcpy(&tmp_part->header, &phead, NVRAM_HEADER_LEN);
 509                 tmp_part->index = cur_index;
 510                 list_add_tail(&tmp_part->partition, &nvram_part->partition);
 511
 512                 cur_index += phead.length * NVRAM_BLOCK_LEN;
 513         }
 514         err = 0;
 515
 516 #ifdef DEBUG_NVRAM
 517         nvram_print_partitions("NVRAM Partitions");
 518 #endif
 519
 520  out:
 521         kfree(header);
 522         return err;
 523 }
 524
 525 static int __init nvram_init(void)
 526 {
 527         int rc;
 528
 529         BUILD_BUG_ON(NVRAM_BLOCK_LEN != 16);
 530
 531         if (ppc_md.nvram_size == NULL || ppc_md.nvram_size() <= 0)
 532                 return  -ENODEV;
 533
 534         rc = misc_register(&nvram_dev);
 535         if (rc != 0) {
 536                 printk(KERN_ERR "nvram_init: failed to register device\n");
 537                 return rc;
 538         }
 539
 540         return rc;
 541 }
 542
 543 void __exit nvram_cleanup(void)
 544 {
 545         misc_deregister( &nvram_dev );
 546 }
 547
 548 module_init(nvram_init);
 549 module_exit(nvram_cleanup);
 550 MODULE_LICENSE("GPL");