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 * 1.3 Wim Van Sebroeck: convert PRINT_PROC to seq_file 36 */ 37 38 #define NVRAM_VERSION "1.3" 39 40 #include <linux/module.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 ?? */ 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 kernel/time/ntp.c vs. this driver.) 98 */ 99 100 #include <linux/types.h> 101 #include <linux/errno.h> 102 #include <linux/miscdevice.h> 103 #include <linux/ioport.h> 104 #include <linux/fcntl.h> 105 #include <linux/mc146818rtc.h> 106 #include <linux/init.h> 107 #include <linux/proc_fs.h> 108 #include <linux/seq_file.h> 109 #include <linux/spinlock.h> 110 #include <linux/io.h> 111 #include <linux/uaccess.h> 112 #include <linux/mutex.h> 113 #include <linux/pagemap.h> 114 115 116 static DEFINE_MUTEX(nvram_mutex); 117 static DEFINE_SPINLOCK(nvram_state_lock); 118 static int nvram_open_cnt; /* #times opened */ 119 static int nvram_open_mode; /* special open modes */ 120 #define NVRAM_WRITE 1 /* opened for writing (exclusive) */ 121 #define NVRAM_EXCL 2 /* opened with O_EXCL */ 122 123 static int mach_check_checksum(void); 124 static void mach_set_checksum(void); 125 126 #ifdef CONFIG_PROC_FS 127 static void mach_proc_infos(unsigned char *contents, struct seq_file *seq, 128 void *offset); 129 #endif 130 131 /* 132 * These functions are provided to be called internally or by other parts of 133 * the kernel. It's up to the caller to ensure correct checksum before reading 134 * or after writing (needs to be done only once). 135 * 136 * It is worth noting that these functions all access bytes of general 137 * purpose memory in the NVRAM - that is to say, they all add the 138 * NVRAM_FIRST_BYTE offset. Pass them offsets into NVRAM as if you did not 139 * know about the RTC cruft. 140 */ 141 142 unsigned char __nvram_read_byte(int i) 143 { 144 return CMOS_READ(NVRAM_FIRST_BYTE + i); 145 } 146 EXPORT_SYMBOL(__nvram_read_byte); 147 148 unsigned char nvram_read_byte(int i) 149 { 150 unsigned long flags; 151 unsigned char c; 152 153 spin_lock_irqsave(&rtc_lock, flags); 154 c = __nvram_read_byte(i); 155 spin_unlock_irqrestore(&rtc_lock, flags); 156 return c; 157 } 158 EXPORT_SYMBOL(nvram_read_byte); 159 160 /* This races nicely with trying to read with checksum checking (nvram_read) */ 161 void __nvram_write_byte(unsigned char c, int i) 162 { 163 CMOS_WRITE(c, NVRAM_FIRST_BYTE + i); 164 } 165 EXPORT_SYMBOL(__nvram_write_byte); 166 167 void nvram_write_byte(unsigned char c, int i) 168 { 169 unsigned long flags; 170 171 spin_lock_irqsave(&rtc_lock, flags); 172 __nvram_write_byte(c, i); 173 spin_unlock_irqrestore(&rtc_lock, flags); 174 } 175 EXPORT_SYMBOL(nvram_write_byte); 176 177 int __nvram_check_checksum(void) 178 { 179 return mach_check_checksum(); 180 } 181 EXPORT_SYMBOL(__nvram_check_checksum); 182 183 int nvram_check_checksum(void) 184 { 185 unsigned long flags; 186 int rv; 187 188 spin_lock_irqsave(&rtc_lock, flags); 189 rv = __nvram_check_checksum(); 190 spin_unlock_irqrestore(&rtc_lock, flags); 191 return rv; 192 } 193 EXPORT_SYMBOL(nvram_check_checksum); 194 195 static void __nvram_set_checksum(void) 196 { 197 mach_set_checksum(); 198 } 199 200 #if 0 201 void 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 return generic_file_llseek_size(file, offset, origin, MAX_LFS_FILESIZE, 218 NVRAM_BYTES); 219 } 220 221 static ssize_t nvram_read(struct file *file, char __user *buf, 222 size_t count, loff_t *ppos) 223 { 224 unsigned char contents[NVRAM_BYTES]; 225 unsigned i = *ppos; 226 unsigned char *tmp; 227 228 spin_lock_irq(&rtc_lock); 229 230 if (!__nvram_check_checksum()) 231 goto checksum_err; 232 233 for (tmp = contents; count-- > 0 && i < NVRAM_BYTES; ++i, ++tmp) 234 *tmp = __nvram_read_byte(i); 235 236 spin_unlock_irq(&rtc_lock); 237 238 if (copy_to_user(buf, contents, tmp - contents)) 239 return -EFAULT; 240 241 *ppos = i; 242 243 return tmp - contents; 244 245 checksum_err: 246 spin_unlock_irq(&rtc_lock); 247 return -EIO; 248 } 249 250 static ssize_t nvram_write(struct file *file, const char __user *buf, 251 size_t count, loff_t *ppos) 252 { 253 unsigned char contents[NVRAM_BYTES]; 254 unsigned i = *ppos; 255 unsigned char *tmp; 256 257 if (i >= NVRAM_BYTES) 258 return 0; /* Past EOF */ 259 260 if (count > NVRAM_BYTES - i) 261 count = NVRAM_BYTES - i; 262 if (count > NVRAM_BYTES) 263 return -EFAULT; /* Can't happen, but prove it to gcc */ 264 265 if (copy_from_user(contents, buf, count)) 266 return -EFAULT; 267 268 spin_lock_irq(&rtc_lock); 269 270 if (!__nvram_check_checksum()) 271 goto checksum_err; 272 273 for (tmp = contents; count--; ++i, ++tmp) 274 __nvram_write_byte(*tmp, i); 275 276 __nvram_set_checksum(); 277 278 spin_unlock_irq(&rtc_lock); 279 280 *ppos = i; 281 282 return tmp - contents; 283 284 checksum_err: 285 spin_unlock_irq(&rtc_lock); 286 return -EIO; 287 } 288 289 static long nvram_ioctl(struct file *file, unsigned int cmd, 290 unsigned long arg) 291 { 292 int i; 293 294 switch (cmd) { 295 296 case NVRAM_INIT: 297 /* initialize NVRAM contents and checksum */ 298 if (!capable(CAP_SYS_ADMIN)) 299 return -EACCES; 300 301 mutex_lock(&nvram_mutex); 302 spin_lock_irq(&rtc_lock); 303 304 for (i = 0; i < NVRAM_BYTES; ++i) 305 __nvram_write_byte(0, i); 306 __nvram_set_checksum(); 307 308 spin_unlock_irq(&rtc_lock); 309 mutex_unlock(&nvram_mutex); 310 return 0; 311 312 case NVRAM_SETCKS: 313 /* just set checksum, contents unchanged (maybe useful after 314 * checksum garbaged somehow...) */ 315 if (!capable(CAP_SYS_ADMIN)) 316 return -EACCES; 317 318 mutex_lock(&nvram_mutex); 319 spin_lock_irq(&rtc_lock); 320 __nvram_set_checksum(); 321 spin_unlock_irq(&rtc_lock); 322 mutex_unlock(&nvram_mutex); 323 return 0; 324 325 default: 326 return -ENOTTY; 327 } 328 } 329 330 static int nvram_open(struct inode *inode, struct file *file) 331 { 332 spin_lock(&nvram_state_lock); 333 334 if ((nvram_open_cnt && (file->f_flags & O_EXCL)) || 335 (nvram_open_mode & NVRAM_EXCL) || 336 ((file->f_mode & FMODE_WRITE) && (nvram_open_mode & NVRAM_WRITE))) { 337 spin_unlock(&nvram_state_lock); 338 return -EBUSY; 339 } 340 341 if (file->f_flags & O_EXCL) 342 nvram_open_mode |= NVRAM_EXCL; 343 if (file->f_mode & FMODE_WRITE) 344 nvram_open_mode |= NVRAM_WRITE; 345 nvram_open_cnt++; 346 347 spin_unlock(&nvram_state_lock); 348 349 return 0; 350 } 351 352 static int nvram_release(struct inode *inode, struct file *file) 353 { 354 spin_lock(&nvram_state_lock); 355 356 nvram_open_cnt--; 357 358 /* if only one instance is open, clear the EXCL bit */ 359 if (nvram_open_mode & NVRAM_EXCL) 360 nvram_open_mode &= ~NVRAM_EXCL; 361 if (file->f_mode & FMODE_WRITE) 362 nvram_open_mode &= ~NVRAM_WRITE; 363 364 spin_unlock(&nvram_state_lock); 365 366 return 0; 367 } 368 369 #ifndef CONFIG_PROC_FS 370 static int nvram_add_proc_fs(void) 371 { 372 return 0; 373 } 374 375 #else 376 377 static int nvram_proc_read(struct seq_file *seq, void *offset) 378 { 379 unsigned char contents[NVRAM_BYTES]; 380 int i = 0; 381 382 spin_lock_irq(&rtc_lock); 383 for (i = 0; i < NVRAM_BYTES; ++i) 384 contents[i] = __nvram_read_byte(i); 385 spin_unlock_irq(&rtc_lock); 386 387 mach_proc_infos(contents, seq, offset); 388 389 return 0; 390 } 391 392 static int nvram_add_proc_fs(void) 393 { 394 if (!proc_create_single("driver/nvram", 0, NULL, nvram_proc_read)) 395 return -ENOMEM; 396 return 0; 397 } 398 399 #endif /* CONFIG_PROC_FS */ 400 401 static const struct file_operations nvram_fops = { 402 .owner = THIS_MODULE, 403 .llseek = nvram_llseek, 404 .read = nvram_read, 405 .write = nvram_write, 406 .unlocked_ioctl = nvram_ioctl, 407 .open = nvram_open, 408 .release = nvram_release, 409 }; 410 411 static struct miscdevice nvram_dev = { 412 NVRAM_MINOR, 413 "nvram", 414 &nvram_fops 415 }; 416 417 static int __init nvram_init(void) 418 { 419 int ret; 420 421 /* First test whether the driver should init at all */ 422 if (!CHECK_DRIVER_INIT()) 423 return -ENODEV; 424 425 ret = misc_register(&nvram_dev); 426 if (ret) { 427 printk(KERN_ERR "nvram: can't misc_register on minor=%d\n", 428 NVRAM_MINOR); 429 goto out; 430 } 431 ret = nvram_add_proc_fs(); 432 if (ret) { 433 printk(KERN_ERR "nvram: can't create /proc/driver/nvram\n"); 434 goto outmisc; 435 } 436 ret = 0; 437 printk(KERN_INFO "Non-volatile memory driver v" NVRAM_VERSION "\n"); 438 out: 439 return ret; 440 outmisc: 441 misc_deregister(&nvram_dev); 442 goto out; 443 } 444 445 static void __exit nvram_cleanup_module(void) 446 { 447 remove_proc_entry("driver/nvram", NULL); 448 misc_deregister(&nvram_dev); 449 } 450 451 module_init(nvram_init); 452 module_exit(nvram_cleanup_module); 453 454 /* 455 * Machine specific functions 456 */ 457 458 #if MACH == PC 459 460 static int pc_check_checksum(void) 461 { 462 int i; 463 unsigned short sum = 0; 464 unsigned short expect; 465 466 for (i = PC_CKS_RANGE_START; i <= PC_CKS_RANGE_END; ++i) 467 sum += __nvram_read_byte(i); 468 expect = __nvram_read_byte(PC_CKS_LOC)<<8 | 469 __nvram_read_byte(PC_CKS_LOC+1); 470 return (sum & 0xffff) == expect; 471 } 472 473 static void pc_set_checksum(void) 474 { 475 int i; 476 unsigned short sum = 0; 477 478 for (i = PC_CKS_RANGE_START; i <= PC_CKS_RANGE_END; ++i) 479 sum += __nvram_read_byte(i); 480 __nvram_write_byte(sum >> 8, PC_CKS_LOC); 481 __nvram_write_byte(sum & 0xff, PC_CKS_LOC + 1); 482 } 483 484 #ifdef CONFIG_PROC_FS 485 486 static const char * const floppy_types[] = { 487 "none", "5.25'' 360k", "5.25'' 1.2M", "3.5'' 720k", "3.5'' 1.44M", 488 "3.5'' 2.88M", "3.5'' 2.88M" 489 }; 490 491 static const char * const gfx_types[] = { 492 "EGA, VGA, ... (with BIOS)", 493 "CGA (40 cols)", 494 "CGA (80 cols)", 495 "monochrome", 496 }; 497 498 static void pc_proc_infos(unsigned char *nvram, struct seq_file *seq, 499 void *offset) 500 { 501 int checksum; 502 int type; 503 504 spin_lock_irq(&rtc_lock); 505 checksum = __nvram_check_checksum(); 506 spin_unlock_irq(&rtc_lock); 507 508 seq_printf(seq, "Checksum status: %svalid\n", checksum ? "" : "not "); 509 510 seq_printf(seq, "# floppies : %d\n", 511 (nvram[6] & 1) ? (nvram[6] >> 6) + 1 : 0); 512 seq_printf(seq, "Floppy 0 type : "); 513 type = nvram[2] >> 4; 514 if (type < ARRAY_SIZE(floppy_types)) 515 seq_printf(seq, "%s\n", floppy_types[type]); 516 else 517 seq_printf(seq, "%d (unknown)\n", type); 518 seq_printf(seq, "Floppy 1 type : "); 519 type = nvram[2] & 0x0f; 520 if (type < ARRAY_SIZE(floppy_types)) 521 seq_printf(seq, "%s\n", floppy_types[type]); 522 else 523 seq_printf(seq, "%d (unknown)\n", type); 524 525 seq_printf(seq, "HD 0 type : "); 526 type = nvram[4] >> 4; 527 if (type) 528 seq_printf(seq, "%02x\n", type == 0x0f ? nvram[11] : type); 529 else 530 seq_printf(seq, "none\n"); 531 532 seq_printf(seq, "HD 1 type : "); 533 type = nvram[4] & 0x0f; 534 if (type) 535 seq_printf(seq, "%02x\n", type == 0x0f ? nvram[12] : type); 536 else 537 seq_printf(seq, "none\n"); 538 539 seq_printf(seq, "HD type 48 data: %d/%d/%d C/H/S, precomp %d, lz %d\n", 540 nvram[18] | (nvram[19] << 8), 541 nvram[20], nvram[25], 542 nvram[21] | (nvram[22] << 8), nvram[23] | (nvram[24] << 8)); 543 seq_printf(seq, "HD type 49 data: %d/%d/%d C/H/S, precomp %d, lz %d\n", 544 nvram[39] | (nvram[40] << 8), 545 nvram[41], nvram[46], 546 nvram[42] | (nvram[43] << 8), nvram[44] | (nvram[45] << 8)); 547 548 seq_printf(seq, "DOS base memory: %d kB\n", nvram[7] | (nvram[8] << 8)); 549 seq_printf(seq, "Extended memory: %d kB (configured), %d kB (tested)\n", 550 nvram[9] | (nvram[10] << 8), nvram[34] | (nvram[35] << 8)); 551 552 seq_printf(seq, "Gfx adapter : %s\n", 553 gfx_types[(nvram[6] >> 4) & 3]); 554 555 seq_printf(seq, "FPU : %sinstalled\n", 556 (nvram[6] & 2) ? "" : "not "); 557 558 return; 559 } 560 #endif 561 562 #endif /* MACH == PC */ 563 564 #if MACH == ATARI 565 566 static int atari_check_checksum(void) 567 { 568 int i; 569 unsigned char sum = 0; 570 571 for (i = ATARI_CKS_RANGE_START; i <= ATARI_CKS_RANGE_END; ++i) 572 sum += __nvram_read_byte(i); 573 return (__nvram_read_byte(ATARI_CKS_LOC) == (~sum & 0xff)) && 574 (__nvram_read_byte(ATARI_CKS_LOC + 1) == (sum & 0xff)); 575 } 576 577 static void atari_set_checksum(void) 578 { 579 int i; 580 unsigned char sum = 0; 581 582 for (i = ATARI_CKS_RANGE_START; i <= ATARI_CKS_RANGE_END; ++i) 583 sum += __nvram_read_byte(i); 584 __nvram_write_byte(~sum, ATARI_CKS_LOC); 585 __nvram_write_byte(sum, ATARI_CKS_LOC + 1); 586 } 587 588 #ifdef CONFIG_PROC_FS 589 590 static struct { 591 unsigned char val; 592 const char *name; 593 } boot_prefs[] = { 594 { 0x80, "TOS" }, 595 { 0x40, "ASV" }, 596 { 0x20, "NetBSD (?)" }, 597 { 0x10, "Linux" }, 598 { 0x00, "unspecified" } 599 }; 600 601 static const char * const languages[] = { 602 "English (US)", 603 "German", 604 "French", 605 "English (UK)", 606 "Spanish", 607 "Italian", 608 "6 (undefined)", 609 "Swiss (French)", 610 "Swiss (German)" 611 }; 612 613 static const char * const dateformat[] = { 614 "MM%cDD%cYY", 615 "DD%cMM%cYY", 616 "YY%cMM%cDD", 617 "YY%cDD%cMM", 618 "4 (undefined)", 619 "5 (undefined)", 620 "6 (undefined)", 621 "7 (undefined)" 622 }; 623 624 static const char * const colors[] = { 625 "2", "4", "16", "256", "65536", "??", "??", "??" 626 }; 627 628 static void atari_proc_infos(unsigned char *nvram, struct seq_file *seq, 629 void *offset) 630 { 631 int checksum = nvram_check_checksum(); 632 int i; 633 unsigned vmode; 634 635 seq_printf(seq, "Checksum status : %svalid\n", checksum ? "" : "not "); 636 637 seq_printf(seq, "Boot preference : "); 638 for (i = ARRAY_SIZE(boot_prefs) - 1; i >= 0; --i) { 639 if (nvram[1] == boot_prefs[i].val) { 640 seq_printf(seq, "%s\n", boot_prefs[i].name); 641 break; 642 } 643 } 644 if (i < 0) 645 seq_printf(seq, "0x%02x (undefined)\n", nvram[1]); 646 647 seq_printf(seq, "SCSI arbitration : %s\n", 648 (nvram[16] & 0x80) ? "on" : "off"); 649 seq_printf(seq, "SCSI host ID : "); 650 if (nvram[16] & 0x80) 651 seq_printf(seq, "%d\n", nvram[16] & 7); 652 else 653 seq_printf(seq, "n/a\n"); 654 655 /* the following entries are defined only for the Falcon */ 656 if ((atari_mch_cookie >> 16) != ATARI_MCH_FALCON) 657 return; 658 659 seq_printf(seq, "OS language : "); 660 if (nvram[6] < ARRAY_SIZE(languages)) 661 seq_printf(seq, "%s\n", languages[nvram[6]]); 662 else 663 seq_printf(seq, "%u (undefined)\n", nvram[6]); 664 seq_printf(seq, "Keyboard language: "); 665 if (nvram[7] < ARRAY_SIZE(languages)) 666 seq_printf(seq, "%s\n", languages[nvram[7]]); 667 else 668 seq_printf(seq, "%u (undefined)\n", nvram[7]); 669 seq_printf(seq, "Date format : "); 670 seq_printf(seq, dateformat[nvram[8] & 7], 671 nvram[9] ? nvram[9] : '/', nvram[9] ? nvram[9] : '/'); 672 seq_printf(seq, ", %dh clock\n", nvram[8] & 16 ? 24 : 12); 673 seq_printf(seq, "Boot delay : "); 674 if (nvram[10] == 0) 675 seq_printf(seq, "default"); 676 else 677 seq_printf(seq, "%ds%s\n", nvram[10], 678 nvram[10] < 8 ? ", no memory test" : ""); 679 680 vmode = (nvram[14] << 8) | nvram[15]; 681 seq_printf(seq, 682 "Video mode : %s colors, %d columns, %s %s monitor\n", 683 colors[vmode & 7], 684 vmode & 8 ? 80 : 40, 685 vmode & 16 ? "VGA" : "TV", vmode & 32 ? "PAL" : "NTSC"); 686 seq_printf(seq, " %soverscan, compat. mode %s%s\n", 687 vmode & 64 ? "" : "no ", 688 vmode & 128 ? "on" : "off", 689 vmode & 256 ? 690 (vmode & 16 ? ", line doubling" : ", half screen") : ""); 691 692 return; 693 } 694 #endif 695 696 #endif /* MACH == ATARI */ 697 698 MODULE_LICENSE("GPL"); 699 MODULE_ALIAS_MISCDEV(NVRAM_MINOR); 700