1 /* 2 * CMOS/NV-RAM driver for Linux 3 * 4 * Copyright (C) 1997 Roman Hodek <Roman.Hodek@informatik.uni-erlangen.de> 5 * idea by and with help from Richard Jelinek <rj@suse.de> 6 * Portions copyright (c) 2001,2002 Sun Microsystems (thockin@sun.com) 7 * 8 * This driver allows you to access the contents of the non-volatile memory in 9 * the mc146818rtc.h real-time clock. This chip is built into all PCs and into 10 * many Atari machines. In the former it's called "CMOS-RAM", in the latter 11 * "NVRAM" (NV stands for non-volatile). 12 * 13 * The data are supplied as a (seekable) character device, /dev/nvram. The 14 * size of this file is dependent on the controller. The usual size is 114, 15 * the number of freely available bytes in the memory (i.e., not used by the 16 * RTC itself). 17 * 18 * Checksums over the NVRAM contents are managed by this driver. In case of a 19 * bad checksum, reads and writes return -EIO. The checksum can be initialized 20 * to a sane state either by ioctl(NVRAM_INIT) (clear whole NVRAM) or 21 * ioctl(NVRAM_SETCKS) (doesn't change contents, just makes checksum valid 22 * again; use with care!) 23 * 24 * This file also provides some functions for other parts of the kernel that 25 * want to access the NVRAM: nvram_{read,write,check_checksum,set_checksum}. 26 * Obviously this can be used only if this driver is always configured into 27 * the kernel and is not a module. Since the functions are used by some Atari 28 * drivers, this is the case on the Atari. 29 * 30 * 31 * 1.1 Cesar Barros: SMP locking fixes 32 * added changelog 33 * 1.2 Erik Gilling: Cobalt Networks support 34 * Tim Hockin: general cleanup, Cobalt support 35 */ 36 37 #define NVRAM_VERSION "1.2" 38 39 #include <linux/module.h> 40 #include <linux/smp_lock.h> 41 #include <linux/nvram.h> 42 43 #define PC 1 44 #define ATARI 2 45 46 /* select machine configuration */ 47 #if defined(CONFIG_ATARI) 48 # define MACH ATARI 49 #elif defined(__i386__) || defined(__x86_64__) || defined(__arm__) /* and others?? */ 50 # define MACH PC 51 #else 52 # error Cannot build nvram driver for this machine configuration. 53 #endif 54 55 #if MACH == PC 56 57 /* RTC in a PC */ 58 #define CHECK_DRIVER_INIT() 1 59 60 /* On PCs, the checksum is built only over bytes 2..31 */ 61 #define PC_CKS_RANGE_START 2 62 #define PC_CKS_RANGE_END 31 63 #define PC_CKS_LOC 32 64 #define NVRAM_BYTES (128-NVRAM_FIRST_BYTE) 65 66 #define mach_check_checksum pc_check_checksum 67 #define mach_set_checksum pc_set_checksum 68 #define mach_proc_infos pc_proc_infos 69 70 #endif 71 72 #if MACH == ATARI 73 74 /* Special parameters for RTC in Atari machines */ 75 #include <asm/atarihw.h> 76 #include <asm/atariints.h> 77 #define RTC_PORT(x) (TT_RTC_BAS + 2*(x)) 78 #define CHECK_DRIVER_INIT() (MACH_IS_ATARI && ATARIHW_PRESENT(TT_CLK)) 79 80 #define NVRAM_BYTES 50 81 82 /* On Ataris, the checksum is over all bytes except the checksum bytes 83 * themselves; these are at the very end */ 84 #define ATARI_CKS_RANGE_START 0 85 #define ATARI_CKS_RANGE_END 47 86 #define ATARI_CKS_LOC 48 87 88 #define mach_check_checksum atari_check_checksum 89 #define mach_set_checksum atari_set_checksum 90 #define mach_proc_infos atari_proc_infos 91 92 #endif 93 94 /* Note that *all* calls to CMOS_READ and CMOS_WRITE must be done with 95 * rtc_lock held. Due to the index-port/data-port design of the RTC, we 96 * don't want two different things trying to get to it at once. (e.g. the 97 * periodic 11 min sync from time.c vs. this driver.) 98 */ 99 100 #include <linux/types.h> 101 #include <linux/errno.h> 102 #include <linux/miscdevice.h> 103 #include <linux/slab.h> 104 #include <linux/ioport.h> 105 #include <linux/fcntl.h> 106 #include <linux/mc146818rtc.h> 107 #include <linux/init.h> 108 #include <linux/proc_fs.h> 109 #include <linux/spinlock.h> 110 111 #include <asm/io.h> 112 #include <asm/uaccess.h> 113 #include <asm/system.h> 114 115 static DEFINE_SPINLOCK(nvram_state_lock); 116 static int nvram_open_cnt; /* #times opened */ 117 static int nvram_open_mode; /* special open modes */ 118 #define NVRAM_WRITE 1 /* opened for writing (exclusive) */ 119 #define NVRAM_EXCL 2 /* opened with O_EXCL */ 120 121 static int mach_check_checksum(void); 122 static void mach_set_checksum(void); 123 124 #ifdef CONFIG_PROC_FS 125 static int mach_proc_infos(unsigned char *contents, char *buffer, int *len, 126 off_t *begin, off_t offset, int size); 127 #endif 128 129 /* 130 * These functions are provided to be called internally or by other parts of 131 * the kernel. It's up to the caller to ensure correct checksum before reading 132 * or after writing (needs to be done only once). 133 * 134 * It is worth noting that these functions all access bytes of general 135 * purpose memory in the NVRAM - that is to say, they all add the 136 * NVRAM_FIRST_BYTE offset. Pass them offsets into NVRAM as if you did not 137 * know about the RTC cruft. 138 */ 139 140 unsigned char 141 __nvram_read_byte(int i) 142 { 143 return CMOS_READ(NVRAM_FIRST_BYTE + i); 144 } 145 146 unsigned char 147 nvram_read_byte(int i) 148 { 149 unsigned long flags; 150 unsigned char c; 151 152 spin_lock_irqsave(&rtc_lock, flags); 153 c = __nvram_read_byte(i); 154 spin_unlock_irqrestore(&rtc_lock, flags); 155 return c; 156 } 157 158 /* This races nicely with trying to read with checksum checking (nvram_read) */ 159 void 160 __nvram_write_byte(unsigned char c, int i) 161 { 162 CMOS_WRITE(c, NVRAM_FIRST_BYTE + i); 163 } 164 165 void 166 nvram_write_byte(unsigned char c, int i) 167 { 168 unsigned long flags; 169 170 spin_lock_irqsave(&rtc_lock, flags); 171 __nvram_write_byte(c, i); 172 spin_unlock_irqrestore(&rtc_lock, flags); 173 } 174 175 int 176 __nvram_check_checksum(void) 177 { 178 return mach_check_checksum(); 179 } 180 181 int 182 nvram_check_checksum(void) 183 { 184 unsigned long flags; 185 int rv; 186 187 spin_lock_irqsave(&rtc_lock, flags); 188 rv = __nvram_check_checksum(); 189 spin_unlock_irqrestore(&rtc_lock, flags); 190 return rv; 191 } 192 193 static void 194 __nvram_set_checksum(void) 195 { 196 mach_set_checksum(); 197 } 198 199 #if 0 200 void 201 nvram_set_checksum(void) 202 { 203 unsigned long flags; 204 205 spin_lock_irqsave(&rtc_lock, flags); 206 __nvram_set_checksum(); 207 spin_unlock_irqrestore(&rtc_lock, flags); 208 } 209 #endif /* 0 */ 210 211 /* 212 * The are the file operation function for user access to /dev/nvram 213 */ 214 215 static loff_t nvram_llseek(struct file *file,loff_t offset, int origin ) 216 { 217 lock_kernel(); 218 switch (origin) { 219 case 0: 220 /* nothing to do */ 221 break; 222 case 1: 223 offset += file->f_pos; 224 break; 225 case 2: 226 offset += NVRAM_BYTES; 227 break; 228 } 229 unlock_kernel(); 230 return (offset >= 0) ? (file->f_pos = offset) : -EINVAL; 231 } 232 233 static ssize_t 234 nvram_read(struct file *file, char __user *buf, size_t count, loff_t *ppos) 235 { 236 unsigned char contents[NVRAM_BYTES]; 237 unsigned i = *ppos; 238 unsigned char *tmp; 239 240 spin_lock_irq(&rtc_lock); 241 242 if (!__nvram_check_checksum()) 243 goto checksum_err; 244 245 for (tmp = contents; count-- > 0 && i < NVRAM_BYTES; ++i, ++tmp) 246 *tmp = __nvram_read_byte(i); 247 248 spin_unlock_irq(&rtc_lock); 249 250 if (copy_to_user(buf, contents, tmp - contents)) 251 return -EFAULT; 252 253 *ppos = i; 254 255 return tmp - contents; 256 257 checksum_err: 258 spin_unlock_irq(&rtc_lock); 259 return -EIO; 260 } 261 262 static ssize_t 263 nvram_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos) 264 { 265 unsigned char contents[NVRAM_BYTES]; 266 unsigned i = *ppos; 267 unsigned char *tmp; 268 int len; 269 270 len = (NVRAM_BYTES - i) < count ? (NVRAM_BYTES - i) : count; 271 if (copy_from_user(contents, buf, len)) 272 return -EFAULT; 273 274 spin_lock_irq(&rtc_lock); 275 276 if (!__nvram_check_checksum()) 277 goto checksum_err; 278 279 for (tmp = contents; count-- > 0 && i < NVRAM_BYTES; ++i, ++tmp) 280 __nvram_write_byte(*tmp, i); 281 282 __nvram_set_checksum(); 283 284 spin_unlock_irq(&rtc_lock); 285 286 *ppos = i; 287 288 return tmp - contents; 289 290 checksum_err: 291 spin_unlock_irq(&rtc_lock); 292 return -EIO; 293 } 294 295 static int 296 nvram_ioctl(struct inode *inode, struct file *file, 297 unsigned int cmd, unsigned long arg) 298 { 299 int i; 300 301 switch (cmd) { 302 303 case NVRAM_INIT: 304 /* initialize NVRAM contents and checksum */ 305 if (!capable(CAP_SYS_ADMIN)) 306 return -EACCES; 307 308 spin_lock_irq(&rtc_lock); 309 310 for (i = 0; i < NVRAM_BYTES; ++i) 311 __nvram_write_byte(0, i); 312 __nvram_set_checksum(); 313 314 spin_unlock_irq(&rtc_lock); 315 return 0; 316 317 case NVRAM_SETCKS: 318 /* just set checksum, contents unchanged (maybe useful after 319 * checksum garbaged somehow...) */ 320 if (!capable(CAP_SYS_ADMIN)) 321 return -EACCES; 322 323 spin_lock_irq(&rtc_lock); 324 __nvram_set_checksum(); 325 spin_unlock_irq(&rtc_lock); 326 return 0; 327 328 default: 329 return -ENOTTY; 330 } 331 } 332 333 static int 334 nvram_open(struct inode *inode, struct file *file) 335 { 336 lock_kernel(); 337 spin_lock(&nvram_state_lock); 338 339 if ((nvram_open_cnt && (file->f_flags & O_EXCL)) || 340 (nvram_open_mode & NVRAM_EXCL) || 341 ((file->f_mode & FMODE_WRITE) && (nvram_open_mode & NVRAM_WRITE))) { 342 spin_unlock(&nvram_state_lock); 343 unlock_kernel(); 344 return -EBUSY; 345 } 346 347 if (file->f_flags & O_EXCL) 348 nvram_open_mode |= NVRAM_EXCL; 349 if (file->f_mode & FMODE_WRITE) 350 nvram_open_mode |= NVRAM_WRITE; 351 nvram_open_cnt++; 352 353 spin_unlock(&nvram_state_lock); 354 unlock_kernel(); 355 356 return 0; 357 } 358 359 static int 360 nvram_release(struct inode *inode, struct file *file) 361 { 362 spin_lock(&nvram_state_lock); 363 364 nvram_open_cnt--; 365 366 /* if only one instance is open, clear the EXCL bit */ 367 if (nvram_open_mode & NVRAM_EXCL) 368 nvram_open_mode &= ~NVRAM_EXCL; 369 if (file->f_mode & FMODE_WRITE) 370 nvram_open_mode &= ~NVRAM_WRITE; 371 372 spin_unlock(&nvram_state_lock); 373 374 return 0; 375 } 376 377 #ifndef CONFIG_PROC_FS 378 static int 379 nvram_read_proc(char *buffer, char **start, off_t offset, 380 int size, int *eof, void *data) 381 { 382 return 0; 383 } 384 #else 385 386 static int 387 nvram_read_proc(char *buffer, char **start, off_t offset, 388 int size, int *eof, void *data) 389 { 390 unsigned char contents[NVRAM_BYTES]; 391 int i, len = 0; 392 off_t begin = 0; 393 394 spin_lock_irq(&rtc_lock); 395 for (i = 0; i < NVRAM_BYTES; ++i) 396 contents[i] = __nvram_read_byte(i); 397 spin_unlock_irq(&rtc_lock); 398 399 *eof = mach_proc_infos(contents, buffer, &len, &begin, offset, size); 400 401 if (offset >= begin + len) 402 return 0; 403 *start = buffer + (offset - begin); 404 return (size < begin + len - offset) ? size : begin + len - offset; 405 406 } 407 408 /* This macro frees the machine specific function from bounds checking and 409 * this like that... */ 410 #define PRINT_PROC(fmt,args...) \ 411 do { \ 412 *len += sprintf(buffer+*len, fmt, ##args); \ 413 if (*begin + *len > offset + size) \ 414 return 0; \ 415 if (*begin + *len < offset) { \ 416 *begin += *len; \ 417 *len = 0; \ 418 } \ 419 } while(0) 420 421 #endif /* CONFIG_PROC_FS */ 422 423 static const struct file_operations nvram_fops = { 424 .owner = THIS_MODULE, 425 .llseek = nvram_llseek, 426 .read = nvram_read, 427 .write = nvram_write, 428 .ioctl = nvram_ioctl, 429 .open = nvram_open, 430 .release = nvram_release, 431 }; 432 433 static struct miscdevice nvram_dev = { 434 NVRAM_MINOR, 435 "nvram", 436 &nvram_fops 437 }; 438 439 static int __init 440 nvram_init(void) 441 { 442 int ret; 443 444 /* First test whether the driver should init at all */ 445 if (!CHECK_DRIVER_INIT()) 446 return -ENODEV; 447 448 ret = misc_register(&nvram_dev); 449 if (ret) { 450 printk(KERN_ERR "nvram: can't misc_register on minor=%d\n", 451 NVRAM_MINOR); 452 goto out; 453 } 454 if (!create_proc_read_entry("driver/nvram", 0, NULL, nvram_read_proc, 455 NULL)) { 456 printk(KERN_ERR "nvram: can't create /proc/driver/nvram\n"); 457 ret = -ENOMEM; 458 goto outmisc; 459 } 460 ret = 0; 461 printk(KERN_INFO "Non-volatile memory driver v" NVRAM_VERSION "\n"); 462 out: 463 return ret; 464 outmisc: 465 misc_deregister(&nvram_dev); 466 goto out; 467 } 468 469 static void __exit 470 nvram_cleanup_module(void) 471 { 472 remove_proc_entry("driver/nvram", NULL); 473 misc_deregister(&nvram_dev); 474 } 475 476 module_init(nvram_init); 477 module_exit(nvram_cleanup_module); 478 479 /* 480 * Machine specific functions 481 */ 482 483 #if MACH == PC 484 485 static int 486 pc_check_checksum(void) 487 { 488 int i; 489 unsigned short sum = 0; 490 unsigned short expect; 491 492 for (i = PC_CKS_RANGE_START; i <= PC_CKS_RANGE_END; ++i) 493 sum += __nvram_read_byte(i); 494 expect = __nvram_read_byte(PC_CKS_LOC)<<8 | 495 __nvram_read_byte(PC_CKS_LOC+1); 496 return ((sum & 0xffff) == expect); 497 } 498 499 static void 500 pc_set_checksum(void) 501 { 502 int i; 503 unsigned short sum = 0; 504 505 for (i = PC_CKS_RANGE_START; i <= PC_CKS_RANGE_END; ++i) 506 sum += __nvram_read_byte(i); 507 __nvram_write_byte(sum >> 8, PC_CKS_LOC); 508 __nvram_write_byte(sum & 0xff, PC_CKS_LOC + 1); 509 } 510 511 #ifdef CONFIG_PROC_FS 512 513 static char *floppy_types[] = { 514 "none", "5.25'' 360k", "5.25'' 1.2M", "3.5'' 720k", "3.5'' 1.44M", 515 "3.5'' 2.88M", "3.5'' 2.88M" 516 }; 517 518 static char *gfx_types[] = { 519 "EGA, VGA, ... (with BIOS)", 520 "CGA (40 cols)", 521 "CGA (80 cols)", 522 "monochrome", 523 }; 524 525 static int 526 pc_proc_infos(unsigned char *nvram, char *buffer, int *len, 527 off_t *begin, off_t offset, int size) 528 { 529 int checksum; 530 int type; 531 532 spin_lock_irq(&rtc_lock); 533 checksum = __nvram_check_checksum(); 534 spin_unlock_irq(&rtc_lock); 535 536 PRINT_PROC("Checksum status: %svalid\n", checksum ? "" : "not "); 537 538 PRINT_PROC("# floppies : %d\n", 539 (nvram[6] & 1) ? (nvram[6] >> 6) + 1 : 0); 540 PRINT_PROC("Floppy 0 type : "); 541 type = nvram[2] >> 4; 542 if (type < ARRAY_SIZE(floppy_types)) 543 PRINT_PROC("%s\n", floppy_types[type]); 544 else 545 PRINT_PROC("%d (unknown)\n", type); 546 PRINT_PROC("Floppy 1 type : "); 547 type = nvram[2] & 0x0f; 548 if (type < ARRAY_SIZE(floppy_types)) 549 PRINT_PROC("%s\n", floppy_types[type]); 550 else 551 PRINT_PROC("%d (unknown)\n", type); 552 553 PRINT_PROC("HD 0 type : "); 554 type = nvram[4] >> 4; 555 if (type) 556 PRINT_PROC("%02x\n", type == 0x0f ? nvram[11] : type); 557 else 558 PRINT_PROC("none\n"); 559 560 PRINT_PROC("HD 1 type : "); 561 type = nvram[4] & 0x0f; 562 if (type) 563 PRINT_PROC("%02x\n", type == 0x0f ? nvram[12] : type); 564 else 565 PRINT_PROC("none\n"); 566 567 PRINT_PROC("HD type 48 data: %d/%d/%d C/H/S, precomp %d, lz %d\n", 568 nvram[18] | (nvram[19] << 8), 569 nvram[20], nvram[25], 570 nvram[21] | (nvram[22] << 8), nvram[23] | (nvram[24] << 8)); 571 PRINT_PROC("HD type 49 data: %d/%d/%d C/H/S, precomp %d, lz %d\n", 572 nvram[39] | (nvram[40] << 8), 573 nvram[41], nvram[46], 574 nvram[42] | (nvram[43] << 8), nvram[44] | (nvram[45] << 8)); 575 576 PRINT_PROC("DOS base memory: %d kB\n", nvram[7] | (nvram[8] << 8)); 577 PRINT_PROC("Extended memory: %d kB (configured), %d kB (tested)\n", 578 nvram[9] | (nvram[10] << 8), nvram[34] | (nvram[35] << 8)); 579 580 PRINT_PROC("Gfx adapter : %s\n", gfx_types[(nvram[6] >> 4) & 3]); 581 582 PRINT_PROC("FPU : %sinstalled\n", 583 (nvram[6] & 2) ? "" : "not "); 584 585 return 1; 586 } 587 #endif 588 589 #endif /* MACH == PC */ 590 591 #if MACH == ATARI 592 593 static int 594 atari_check_checksum(void) 595 { 596 int i; 597 unsigned char sum = 0; 598 599 for (i = ATARI_CKS_RANGE_START; i <= ATARI_CKS_RANGE_END; ++i) 600 sum += __nvram_read_byte(i); 601 return (__nvram_read_byte(ATARI_CKS_LOC) == (~sum & 0xff) && 602 __nvram_read_byte(ATARI_CKS_LOC + 1) == (sum & 0xff)); 603 } 604 605 static void 606 atari_set_checksum(void) 607 { 608 int i; 609 unsigned char sum = 0; 610 611 for (i = ATARI_CKS_RANGE_START; i <= ATARI_CKS_RANGE_END; ++i) 612 sum += __nvram_read_byte(i); 613 __nvram_write_byte(~sum, ATARI_CKS_LOC); 614 __nvram_write_byte(sum, ATARI_CKS_LOC + 1); 615 } 616 617 #ifdef CONFIG_PROC_FS 618 619 static struct { 620 unsigned char val; 621 char *name; 622 } boot_prefs[] = { 623 { 0x80, "TOS" }, 624 { 0x40, "ASV" }, 625 { 0x20, "NetBSD (?)" }, 626 { 0x10, "Linux" }, 627 { 0x00, "unspecified" } 628 }; 629 630 static char *languages[] = { 631 "English (US)", 632 "German", 633 "French", 634 "English (UK)", 635 "Spanish", 636 "Italian", 637 "6 (undefined)", 638 "Swiss (French)", 639 "Swiss (German)" 640 }; 641 642 static char *dateformat[] = { 643 "MM%cDD%cYY", 644 "DD%cMM%cYY", 645 "YY%cMM%cDD", 646 "YY%cDD%cMM", 647 "4 (undefined)", 648 "5 (undefined)", 649 "6 (undefined)", 650 "7 (undefined)" 651 }; 652 653 static char *colors[] = { 654 "2", "4", "16", "256", "65536", "??", "??", "??" 655 }; 656 657 static int 658 atari_proc_infos(unsigned char *nvram, char *buffer, int *len, 659 off_t *begin, off_t offset, int size) 660 { 661 int checksum = nvram_check_checksum(); 662 int i; 663 unsigned vmode; 664 665 PRINT_PROC("Checksum status : %svalid\n", checksum ? "" : "not "); 666 667 PRINT_PROC("Boot preference : "); 668 for (i = ARRAY_SIZE(boot_prefs) - 1; i >= 0; --i) { 669 if (nvram[1] == boot_prefs[i].val) { 670 PRINT_PROC("%s\n", boot_prefs[i].name); 671 break; 672 } 673 } 674 if (i < 0) 675 PRINT_PROC("0x%02x (undefined)\n", nvram[1]); 676 677 PRINT_PROC("SCSI arbitration : %s\n", 678 (nvram[16] & 0x80) ? "on" : "off"); 679 PRINT_PROC("SCSI host ID : "); 680 if (nvram[16] & 0x80) 681 PRINT_PROC("%d\n", nvram[16] & 7); 682 else 683 PRINT_PROC("n/a\n"); 684 685 /* the following entries are defined only for the Falcon */ 686 if ((atari_mch_cookie >> 16) != ATARI_MCH_FALCON) 687 return 1; 688 689 PRINT_PROC("OS language : "); 690 if (nvram[6] < ARRAY_SIZE(languages)) 691 PRINT_PROC("%s\n", languages[nvram[6]]); 692 else 693 PRINT_PROC("%u (undefined)\n", nvram[6]); 694 PRINT_PROC("Keyboard language: "); 695 if (nvram[7] < ARRAY_SIZE(languages)) 696 PRINT_PROC("%s\n", languages[nvram[7]]); 697 else 698 PRINT_PROC("%u (undefined)\n", nvram[7]); 699 PRINT_PROC("Date format : "); 700 PRINT_PROC(dateformat[nvram[8] & 7], 701 nvram[9] ? nvram[9] : '/', nvram[9] ? nvram[9] : '/'); 702 PRINT_PROC(", %dh clock\n", nvram[8] & 16 ? 24 : 12); 703 PRINT_PROC("Boot delay : "); 704 if (nvram[10] == 0) 705 PRINT_PROC("default"); 706 else 707 PRINT_PROC("%ds%s\n", nvram[10], 708 nvram[10] < 8 ? ", no memory test" : ""); 709 710 vmode = (nvram[14] << 8) || nvram[15]; 711 PRINT_PROC("Video mode : %s colors, %d columns, %s %s monitor\n", 712 colors[vmode & 7], 713 vmode & 8 ? 80 : 40, 714 vmode & 16 ? "VGA" : "TV", vmode & 32 ? "PAL" : "NTSC"); 715 PRINT_PROC(" %soverscan, compat. mode %s%s\n", 716 vmode & 64 ? "" : "no ", 717 vmode & 128 ? "on" : "off", 718 vmode & 256 ? 719 (vmode & 16 ? ", line doubling" : ", half screen") : ""); 720 721 return 1; 722 } 723 #endif 724 725 #endif /* MACH == ATARI */ 726 727 MODULE_LICENSE("GPL"); 728 729 EXPORT_SYMBOL(__nvram_read_byte); 730 EXPORT_SYMBOL(nvram_read_byte); 731 EXPORT_SYMBOL(__nvram_write_byte); 732 EXPORT_SYMBOL(nvram_write_byte); 733 EXPORT_SYMBOL(__nvram_check_checksum); 734 EXPORT_SYMBOL(nvram_check_checksum); 735 MODULE_ALIAS_MISCDEV(NVRAM_MINOR); 736