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"); 572