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 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/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/smp_lock.h> 113 114#include <asm/system.h> 115 116static DEFINE_SPINLOCK(nvram_state_lock); 117static int nvram_open_cnt; /* #times opened */ 118static int nvram_open_mode; /* special open modes */ 119#define NVRAM_WRITE 1 /* opened for writing (exclusive) */ 120#define NVRAM_EXCL 2 /* opened with O_EXCL */ 121 122static int mach_check_checksum(void); 123static void mach_set_checksum(void); 124 125#ifdef CONFIG_PROC_FS 126static void mach_proc_infos(unsigned char *contents, struct seq_file *seq, 127 void *offset); 128#endif 129 130/* 131 * These functions are provided to be called internally or by other parts of 132 * the kernel. It's up to the caller to ensure correct checksum before reading 133 * or after writing (needs to be done only once). 134 * 135 * It is worth noting that these functions all access bytes of general 136 * purpose memory in the NVRAM - that is to say, they all add the 137 * NVRAM_FIRST_BYTE offset. Pass them offsets into NVRAM as if you did not 138 * know about the RTC cruft. 139 */ 140 141unsigned char __nvram_read_byte(int i) 142{ 143 return CMOS_READ(NVRAM_FIRST_BYTE + i); 144} 145EXPORT_SYMBOL(__nvram_read_byte); 146 147unsigned char 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} 157EXPORT_SYMBOL(nvram_read_byte); 158 159/* This races nicely with trying to read with checksum checking (nvram_read) */ 160void __nvram_write_byte(unsigned char c, int i) 161{ 162 CMOS_WRITE(c, NVRAM_FIRST_BYTE + i); 163} 164EXPORT_SYMBOL(__nvram_write_byte); 165 166void 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} 174EXPORT_SYMBOL(nvram_write_byte); 175 176int __nvram_check_checksum(void) 177{ 178 return mach_check_checksum(); 179} 180EXPORT_SYMBOL(__nvram_check_checksum); 181 182int 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} 192EXPORT_SYMBOL(nvram_check_checksum); 193 194static void __nvram_set_checksum(void) 195{ 196 mach_set_checksum(); 197} 198 199 200/* 201 * The are the file operation function for user access to /dev/nvram 202 */ 203 204static loff_t nvram_llseek(struct file *file, loff_t offset, int origin) 205{ 206 switch (origin) { 207 case 0: 208 /* nothing to do */ 209 break; 210 case 1: 211 offset += file->f_pos; 212 break; 213 case 2: 214 offset += NVRAM_BYTES; 215 break; 216 } 217 218 return (offset >= 0) ? (file->f_pos = offset) : -EINVAL; 219} 220 221static 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 245checksum_err: 246 spin_unlock_irq(&rtc_lock); 247 return -EIO; 248} 249 250static 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 284checksum_err: 285 spin_unlock_irq(&rtc_lock); 286 return -EIO; 287} 288 289static 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 lock_kernel(); 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 unlock_kernel(); 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 lock_kernel(); 319 spin_lock_irq(&rtc_lock); 320 __nvram_set_checksum(); 321 spin_unlock_irq(&rtc_lock); 322 unlock_kernel(); 323 return 0; 324 325 default: 326 return -ENOTTY; 327 } 328} 329 330static 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 352static 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 370static int nvram_add_proc_fs(void) 371{ 372 return 0; 373} 374 375#else 376 377static 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 392static int nvram_proc_open(struct inode *inode, struct file *file) 393{ 394 return single_open(file, nvram_proc_read, NULL); 395} 396 397static const struct file_operations nvram_proc_fops = { 398 .owner = THIS_MODULE, 399 .open = nvram_proc_open, 400 .read = seq_read, 401 .llseek = seq_lseek, 402 .release = single_release, 403}; 404 405static int nvram_add_proc_fs(void) 406{ 407 if (!proc_create("driver/nvram", 0, NULL, &nvram_proc_fops)) 408 return -ENOMEM; 409 return 0; 410} 411 412#endif /* CONFIG_PROC_FS */ 413 414static const struct file_operations nvram_fops = { 415 .owner = THIS_MODULE, 416 .llseek = nvram_llseek, 417 .read = nvram_read, 418 .write = nvram_write, 419 .unlocked_ioctl = nvram_ioctl, 420 .open = nvram_open, 421 .release = nvram_release, 422}; 423 424static struct miscdevice nvram_dev = { 425 NVRAM_MINOR, 426 "nvram", 427 &nvram_fops 428}; 429 430static int __init nvram_init(void) 431{ 432 int ret; 433 434 /* First test whether the driver should init at all */ 435 if (!CHECK_DRIVER_INIT()) 436 return -ENODEV; 437 438 ret = misc_register(&nvram_dev); 439 if (ret) { 440 printk(KERN_ERR "nvram: can't misc_register on minor=%d\n", 441 NVRAM_MINOR); 442 goto out; 443 } 444 ret = nvram_add_proc_fs(); 445 if (ret) { 446 printk(KERN_ERR "nvram: can't create /proc/driver/nvram\n"); 447 goto outmisc; 448 } 449 ret = 0; 450 printk(KERN_INFO "Non-volatile memory driver v" NVRAM_VERSION "\n"); 451out: 452 return ret; 453outmisc: 454 misc_deregister(&nvram_dev); 455 goto out; 456} 457 458static void __exit nvram_cleanup_module(void) 459{ 460 remove_proc_entry("driver/nvram", NULL); 461 misc_deregister(&nvram_dev); 462} 463 464module_init(nvram_init); 465module_exit(nvram_cleanup_module); 466 467/* 468 * Machine specific functions 469 */ 470 471#if MACH == PC 472 473static int pc_check_checksum(void) 474{ 475 int i; 476 unsigned short sum = 0; 477 unsigned short expect; 478 479 for (i = PC_CKS_RANGE_START; i <= PC_CKS_RANGE_END; ++i) 480 sum += __nvram_read_byte(i); 481 expect = __nvram_read_byte(PC_CKS_LOC)<<8 | 482 __nvram_read_byte(PC_CKS_LOC+1); 483 return (sum & 0xffff) == expect; 484} 485 486static void pc_set_checksum(void) 487{ 488 int i; 489 unsigned short sum = 0; 490 491 for (i = PC_CKS_RANGE_START; i <= PC_CKS_RANGE_END; ++i) 492 sum += __nvram_read_byte(i); 493 __nvram_write_byte(sum >> 8, PC_CKS_LOC); 494 __nvram_write_byte(sum & 0xff, PC_CKS_LOC + 1); 495} 496 497#ifdef CONFIG_PROC_FS 498 499static char *floppy_types[] = { 500 "none", "5.25'' 360k", "5.25'' 1.2M", "3.5'' 720k", "3.5'' 1.44M", 501 "3.5'' 2.88M", "3.5'' 2.88M" 502}; 503 504static char *gfx_types[] = { 505 "EGA, VGA, ... (with BIOS)", 506 "CGA (40 cols)", 507 "CGA (80 cols)", 508 "monochrome", 509}; 510 511static void pc_proc_infos(unsigned char *nvram, struct seq_file *seq, 512 void *offset) 513{ 514 int checksum; 515 int type; 516 517 spin_lock_irq(&rtc_lock); 518 checksum = __nvram_check_checksum(); 519 spin_unlock_irq(&rtc_lock); 520 521 seq_printf(seq, "Checksum status: %svalid\n", checksum ? "" : "not "); 522 523 seq_printf(seq, "# floppies : %d\n", 524 (nvram[6] & 1) ? (nvram[6] >> 6) + 1 : 0); 525 seq_printf(seq, "Floppy 0 type : "); 526 type = nvram[2] >> 4; 527 if (type < ARRAY_SIZE(floppy_types)) 528 seq_printf(seq, "%s\n", floppy_types[type]); 529 else 530 seq_printf(seq, "%d (unknown)\n", type); 531 seq_printf(seq, "Floppy 1 type : "); 532 type = nvram[2] & 0x0f; 533 if (type < ARRAY_SIZE(floppy_types)) 534 seq_printf(seq, "%s\n", floppy_types[type]); 535 else 536 seq_printf(seq, "%d (unknown)\n", type); 537 538 seq_printf(seq, "HD 0 type : "); 539 type = nvram[4] >> 4; 540 if (type) 541 seq_printf(seq, "%02x\n", type == 0x0f ? nvram[11] : type); 542 else 543 seq_printf(seq, "none\n"); 544 545 seq_printf(seq, "HD 1 type : "); 546 type = nvram[4] & 0x0f; 547 if (type) 548 seq_printf(seq, "%02x\n", type == 0x0f ? nvram[12] : type); 549 else 550 seq_printf(seq, "none\n"); 551 552 seq_printf(seq, "HD type 48 data: %d/%d/%d C/H/S, precomp %d, lz %d\n", 553 nvram[18] | (nvram[19] << 8), 554 nvram[20], nvram[25], 555 nvram[21] | (nvram[22] << 8), nvram[23] | (nvram[24] << 8)); 556 seq_printf(seq, "HD type 49 data: %d/%d/%d C/H/S, precomp %d, lz %d\n", 557 nvram[39] | (nvram[40] << 8), 558 nvram[41], nvram[46], 559 nvram[42] | (nvram[43] << 8), nvram[44] | (nvram[45] << 8)); 560 561 seq_printf(seq, "DOS base memory: %d kB\n", nvram[7] | (nvram[8] << 8)); 562 seq_printf(seq, "Extended memory: %d kB (configured), %d kB (tested)\n", 563 nvram[9] | (nvram[10] << 8), nvram[34] | (nvram[35] << 8)); 564 565 seq_printf(seq, "Gfx adapter : %s\n", 566 gfx_types[(nvram[6] >> 4) & 3]); 567 568 seq_printf(seq, "FPU : %sinstalled\n", 569 (nvram[6] & 2) ? "" : "not "); 570 571 return; 572} 573#endif 574 575#endif /* MACH == PC */ 576 577#if MACH == ATARI 578 579static int atari_check_checksum(void) 580{ 581 int i; 582 unsigned char sum = 0; 583 584 for (i = ATARI_CKS_RANGE_START; i <= ATARI_CKS_RANGE_END; ++i) 585 sum += __nvram_read_byte(i); 586 return (__nvram_read_byte(ATARI_CKS_LOC) == (~sum & 0xff)) && 587 (__nvram_read_byte(ATARI_CKS_LOC + 1) == (sum & 0xff)); 588} 589 590static void atari_set_checksum(void) 591{ 592 int i; 593 unsigned char sum = 0; 594 595 for (i = ATARI_CKS_RANGE_START; i <= ATARI_CKS_RANGE_END; ++i) 596 sum += __nvram_read_byte(i); 597 __nvram_write_byte(~sum, ATARI_CKS_LOC); 598 __nvram_write_byte(sum, ATARI_CKS_LOC + 1); 599} 600 601#ifdef CONFIG_PROC_FS 602 603static struct { 604 unsigned char val; 605 char *name; 606} boot_prefs[] = { 607 { 0x80, "TOS" }, 608 { 0x40, "ASV" }, 609 { 0x20, "NetBSD (?)" }, 610 { 0x10, "Linux" }, 611 { 0x00, "unspecified" } 612}; 613 614static char *languages[] = { 615 "English (US)", 616 "German", 617 "French", 618 "English (UK)", 619 "Spanish", 620 "Italian", 621 "6 (undefined)", 622 "Swiss (French)", 623 "Swiss (German)" 624}; 625 626static char *dateformat[] = { 627 "MM%cDD%cYY", 628 "DD%cMM%cYY", 629 "YY%cMM%cDD", 630 "YY%cDD%cMM", 631 "4 (undefined)", 632 "5 (undefined)", 633 "6 (undefined)", 634 "7 (undefined)" 635}; 636 637static char *colors[] = { 638 "2", "4", "16", "256", "65536", "??", "??", "??" 639}; 640 641static void atari_proc_infos(unsigned char *nvram, struct seq_file *seq, 642 void *offset) 643{ 644 int checksum = nvram_check_checksum(); 645 int i; 646 unsigned vmode; 647 648 seq_printf(seq, "Checksum status : %svalid\n", checksum ? "" : "not "); 649 650 seq_printf(seq, "Boot preference : "); 651 for (i = ARRAY_SIZE(boot_prefs) - 1; i >= 0; --i) { 652 if (nvram[1] == boot_prefs[i].val) { 653 seq_printf(seq, "%s\n", boot_prefs[i].name); 654 break; 655 } 656 } 657 if (i < 0) 658 seq_printf(seq, "0x%02x (undefined)\n", nvram[1]); 659 660 seq_printf(seq, "SCSI arbitration : %s\n", 661 (nvram[16] & 0x80) ? "on" : "off"); 662 seq_printf(seq, "SCSI host ID : "); 663 if (nvram[16] & 0x80) 664 seq_printf(seq, "%d\n", nvram[16] & 7); 665 else 666 seq_printf(seq, "n/a\n"); 667 668 /* the following entries are defined only for the Falcon */ 669 if ((atari_mch_cookie >> 16) != ATARI_MCH_FALCON) 670 return; 671 672 seq_printf(seq, "OS language : "); 673 if (nvram[6] < ARRAY_SIZE(languages)) 674 seq_printf(seq, "%s\n", languages[nvram[6]]); 675 else 676 seq_printf(seq, "%u (undefined)\n", nvram[6]); 677 seq_printf(seq, "Keyboard language: "); 678 if (nvram[7] < ARRAY_SIZE(languages)) 679 seq_printf(seq, "%s\n", languages[nvram[7]]); 680 else 681 seq_printf(seq, "%u (undefined)\n", nvram[7]); 682 seq_printf(seq, "Date format : "); 683 seq_printf(seq, dateformat[nvram[8] & 7], 684 nvram[9] ? nvram[9] : '/', nvram[9] ? nvram[9] : '/'); 685 seq_printf(seq, ", %dh clock\n", nvram[8] & 16 ? 24 : 12); 686 seq_printf(seq, "Boot delay : "); 687 if (nvram[10] == 0) 688 seq_printf(seq, "default"); 689 else 690 seq_printf(seq, "%ds%s\n", nvram[10], 691 nvram[10] < 8 ? ", no memory test" : ""); 692 693 vmode = (nvram[14] << 8) || nvram[15]; 694 seq_printf(seq, 695 "Video mode : %s colors, %d columns, %s %s monitor\n", 696 colors[vmode & 7], 697 vmode & 8 ? 80 : 40, 698 vmode & 16 ? "VGA" : "TV", vmode & 32 ? "PAL" : "NTSC"); 699 seq_printf(seq, " %soverscan, compat. mode %s%s\n", 700 vmode & 64 ? "" : "no ", 701 vmode & 128 ? "on" : "off", 702 vmode & 256 ? 703 (vmode & 16 ? ", line doubling" : ", half screen") : ""); 704 705 return; 706} 707#endif 708 709#endif /* MACH == ATARI */ 710 711MODULE_LICENSE("GPL"); 712MODULE_ALIAS_MISCDEV(NVRAM_MINOR); 713