drivers/char/nvram.c

   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
 116 static DEFINE_SPINLOCK(nvram_state_lock);
 117 static int nvram_open_cnt;      /* #times opened */
 118 static 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
 122 static int mach_check_checksum(void);
 123 static void mach_set_checksum(void);
 124
 125 #ifdef CONFIG_PROC_FS
 126 static 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
 141 unsigned char __nvram_read_byte(int i)
 142 {
 143         return CMOS_READ(NVRAM_FIRST_BYTE + i);
 144 }
 145 EXPORT_SYMBOL(__nvram_read_byte);
 146
 147 unsigned 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 }
 157 EXPORT_SYMBOL(nvram_read_byte);
 158
 159 /* This races nicely with trying to read with checksum checking (nvram_read) */
 160 void __nvram_write_byte(unsigned char c, int i)
 161 {
 162         CMOS_WRITE(c, NVRAM_FIRST_BYTE + i);
 163 }
 164 EXPORT_SYMBOL(__nvram_write_byte);
 165
 166 void 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 EXPORT_SYMBOL(nvram_write_byte);
 175
 176 int __nvram_check_checksum(void)
 177 {
 178         return mach_check_checksum();
 179 }
 180 EXPORT_SYMBOL(__nvram_check_checksum);
 181
 182 int 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 EXPORT_SYMBOL(nvram_check_checksum);
 193
 194 static void __nvram_set_checksum(void)
 195 {
 196         mach_set_checksum();
 197 }
 198
 199 #if 0
 200 void nvram_set_checksum(void)
 201 {
 202         unsigned long flags;
 203
 204         spin_lock_irqsave(&rtc_lock, flags);
 205         __nvram_set_checksum();
 206         spin_unlock_irqrestore(&rtc_lock, flags);
 207 }
 208 #endif  /*  0  */
 209
 210 /*
 211  * The are the file operation function for user access to /dev/nvram
 212  */
 213
 214 static loff_t nvram_llseek(struct file *file, loff_t offset, int origin)
 215 {
 216         switch (origin) {
 217         case 0:
 218                 /* nothing to do */
 219                 break;
 220         case 1:
 221                 offset += file->f_pos;
 222                 break;
 223         case 2:
 224                 offset += NVRAM_BYTES;
 225                 break;
 226         }
 227
 228         return (offset >= 0) ? (file->f_pos = offset) : -EINVAL;
 229 }
 230
 231 static ssize_t nvram_read(struct file *file, char __user *buf,
 232                                                 size_t count, loff_t *ppos)
 233 {
 234         unsigned char contents[NVRAM_BYTES];
 235         unsigned i = *ppos;
 236         unsigned char *tmp;
 237
 238         spin_lock_irq(&rtc_lock);
 239
 240         if (!__nvram_check_checksum())
 241                 goto checksum_err;
 242
 243         for (tmp = contents; count-- > 0 && i < NVRAM_BYTES; ++i, ++tmp)
 244                 *tmp = __nvram_read_byte(i);
 245
 246         spin_unlock_irq(&rtc_lock);
 247
 248         if (copy_to_user(buf, contents, tmp - contents))
 249                 return -EFAULT;
 250
 251         *ppos = i;
 252
 253         return tmp - contents;
 254
 255 checksum_err:
 256         spin_unlock_irq(&rtc_lock);
 257         return -EIO;
 258 }
 259
 260 static ssize_t nvram_write(struct file *file, const char __user *buf,
 261                                                 size_t count, loff_t *ppos)
 262 {
 263         unsigned char contents[NVRAM_BYTES];
 264         unsigned i = *ppos;
 265         unsigned char *tmp;
 266
 267         if (i >= NVRAM_BYTES)
 268                 return 0;       /* Past EOF */
 269
 270         if (count > NVRAM_BYTES - i)
 271                 count = NVRAM_BYTES - i;
 272         if (count > NVRAM_BYTES)
 273                 return -EFAULT; /* Can't happen, but prove it to gcc */
 274
 275         if (copy_from_user(contents, buf, count))
 276                 return -EFAULT;
 277
 278         spin_lock_irq(&rtc_lock);
 279
 280         if (!__nvram_check_checksum())
 281                 goto checksum_err;
 282
 283         for (tmp = contents; count--; ++i, ++tmp)
 284                 __nvram_write_byte(*tmp, i);
 285
 286         __nvram_set_checksum();
 287
 288         spin_unlock_irq(&rtc_lock);
 289
 290         *ppos = i;
 291
 292         return tmp - contents;
 293
 294 checksum_err:
 295         spin_unlock_irq(&rtc_lock);
 296         return -EIO;
 297 }
 298
 299 static long nvram_ioctl(struct file *file, unsigned int cmd,
 300                         unsigned long arg)
 301 {
 302         int i;
 303
 304         switch (cmd) {
 305
 306         case NVRAM_INIT:
 307                 /* initialize NVRAM contents and checksum */
 308                 if (!capable(CAP_SYS_ADMIN))
 309                         return -EACCES;
 310
 311                 lock_kernel();
 312                 spin_lock_irq(&rtc_lock);
 313
 314                 for (i = 0; i < NVRAM_BYTES; ++i)
 315                         __nvram_write_byte(0, i);
 316                 __nvram_set_checksum();
 317
 318                 spin_unlock_irq(&rtc_lock);
 319                 unlock_kernel();
 320                 return 0;
 321
 322         case NVRAM_SETCKS:
 323                 /* just set checksum, contents unchanged (maybe useful after
 324                  * checksum garbaged somehow...) */
 325                 if (!capable(CAP_SYS_ADMIN))
 326                         return -EACCES;
 327
 328                 lock_kernel();
 329                 spin_lock_irq(&rtc_lock);
 330                 __nvram_set_checksum();
 331                 spin_unlock_irq(&rtc_lock);
 332                 unlock_kernel();
 333                 return 0;
 334
 335         default:
 336                 return -ENOTTY;
 337         }
 338 }
 339
 340 static int nvram_open(struct inode *inode, struct file *file)
 341 {
 342         spin_lock(&nvram_state_lock);
 343
 344         if ((nvram_open_cnt && (file->f_flags & O_EXCL)) ||
 345             (nvram_open_mode & NVRAM_EXCL) ||
 346             ((file->f_mode & FMODE_WRITE) && (nvram_open_mode & NVRAM_WRITE))) {
 347                 spin_unlock(&nvram_state_lock);
 348                 return -EBUSY;
 349         }
 350
 351         if (file->f_flags & O_EXCL)
 352                 nvram_open_mode |= NVRAM_EXCL;
 353         if (file->f_mode & FMODE_WRITE)
 354                 nvram_open_mode |= NVRAM_WRITE;
 355         nvram_open_cnt++;
 356
 357         spin_unlock(&nvram_state_lock);
 358
 359         return 0;
 360 }
 361
 362 static int nvram_release(struct inode *inode, struct file *file)
 363 {
 364         spin_lock(&nvram_state_lock);
 365
 366         nvram_open_cnt--;
 367
 368         /* if only one instance is open, clear the EXCL bit */
 369         if (nvram_open_mode & NVRAM_EXCL)
 370                 nvram_open_mode &= ~NVRAM_EXCL;
 371         if (file->f_mode & FMODE_WRITE)
 372                 nvram_open_mode &= ~NVRAM_WRITE;
 373
 374         spin_unlock(&nvram_state_lock);
 375
 376         return 0;
 377 }
 378
 379 #ifndef CONFIG_PROC_FS
 380 static int nvram_add_proc_fs(void)
 381 {
 382         return 0;
 383 }
 384
 385 #else
 386
 387 static int nvram_proc_read(struct seq_file *seq, void *offset)
 388 {
 389         unsigned char contents[NVRAM_BYTES];
 390         int i = 0;
 391
 392         spin_lock_irq(&rtc_lock);
 393         for (i = 0; i < NVRAM_BYTES; ++i)
 394                 contents[i] = __nvram_read_byte(i);
 395         spin_unlock_irq(&rtc_lock);
 396
 397         mach_proc_infos(contents, seq, offset);
 398
 399         return 0;
 400 }
 401
 402 static int nvram_proc_open(struct inode *inode, struct file *file)
 403 {
 404         return single_open(file, nvram_proc_read, NULL);
 405 }
 406
 407 static const struct file_operations nvram_proc_fops = {
 408         .owner          = THIS_MODULE,
 409         .open           = nvram_proc_open,
 410         .read           = seq_read,
 411         .llseek         = seq_lseek,
 412         .release        = single_release,
 413 };
 414
 415 static int nvram_add_proc_fs(void)
 416 {
 417         if (!proc_create("driver/nvram", 0, NULL, &nvram_proc_fops))
 418                 return -ENOMEM;
 419         return 0;
 420 }
 421
 422 #endif /* CONFIG_PROC_FS */
 423
 424 static const struct file_operations nvram_fops = {
 425         .owner          = THIS_MODULE,
 426         .llseek         = nvram_llseek,
 427         .read           = nvram_read,
 428         .write          = nvram_write,
 429         .unlocked_ioctl = nvram_ioctl,
 430         .open           = nvram_open,
 431         .release        = nvram_release,
 432 };
 433
 434 static struct miscdevice nvram_dev = {
 435         NVRAM_MINOR,
 436         "nvram",
 437         &nvram_fops
 438 };
 439
 440 static int __init 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         ret = nvram_add_proc_fs();
 455         if (ret) {
 456                 printk(KERN_ERR "nvram: can't create /proc/driver/nvram\n");
 457                 goto outmisc;
 458         }
 459         ret = 0;
 460         printk(KERN_INFO "Non-volatile memory driver v" NVRAM_VERSION "\n");
 461 out:
 462         return ret;
 463 outmisc:
 464         misc_deregister(&nvram_dev);
 465         goto out;
 466 }
 467
 468 static void __exit nvram_cleanup_module(void)
 469 {
 470         remove_proc_entry("driver/nvram", NULL);
 471         misc_deregister(&nvram_dev);
 472 }
 473
 474 module_init(nvram_init);
 475 module_exit(nvram_cleanup_module);
 476
 477 /*
 478  * Machine specific functions
 479  */
 480
 481 #if MACH == PC
 482
 483 static int pc_check_checksum(void)
 484 {
 485         int i;
 486         unsigned short sum = 0;
 487         unsigned short expect;
 488
 489         for (i = PC_CKS_RANGE_START; i <= PC_CKS_RANGE_END; ++i)
 490                 sum += __nvram_read_byte(i);
 491         expect = __nvram_read_byte(PC_CKS_LOC)<<8 |
 492             __nvram_read_byte(PC_CKS_LOC+1);
 493         return (sum & 0xffff) == expect;
 494 }
 495
 496 static void pc_set_checksum(void)
 497 {
 498         int i;
 499         unsigned short sum = 0;
 500
 501         for (i = PC_CKS_RANGE_START; i <= PC_CKS_RANGE_END; ++i)
 502                 sum += __nvram_read_byte(i);
 503         __nvram_write_byte(sum >> 8, PC_CKS_LOC);
 504         __nvram_write_byte(sum & 0xff, PC_CKS_LOC + 1);
 505 }
 506
 507 #ifdef CONFIG_PROC_FS
 508
 509 static char *floppy_types[] = {
 510         "none", "5.25'' 360k", "5.25'' 1.2M", "3.5'' 720k", "3.5'' 1.44M",
 511         "3.5'' 2.88M", "3.5'' 2.88M"
 512 };
 513
 514 static char *gfx_types[] = {
 515         "EGA, VGA, ... (with BIOS)",
 516         "CGA (40 cols)",
 517         "CGA (80 cols)",
 518         "monochrome",
 519 };
 520
 521 static void pc_proc_infos(unsigned char *nvram, struct seq_file *seq,
 522                                                                 void *offset)
 523 {
 524         int checksum;
 525         int type;
 526
 527         spin_lock_irq(&rtc_lock);
 528         checksum = __nvram_check_checksum();
 529         spin_unlock_irq(&rtc_lock);
 530
 531         seq_printf(seq, "Checksum status: %svalid\n", checksum ? "" : "not ");
 532
 533         seq_printf(seq, "# floppies     : %d\n",
 534             (nvram[6] & 1) ? (nvram[6] >> 6) + 1 : 0);
 535         seq_printf(seq, "Floppy 0 type  : ");
 536         type = nvram[2] >> 4;
 537         if (type < ARRAY_SIZE(floppy_types))
 538                 seq_printf(seq, "%s\n", floppy_types[type]);
 539         else
 540                 seq_printf(seq, "%d (unknown)\n", type);
 541         seq_printf(seq, "Floppy 1 type  : ");
 542         type = nvram[2] & 0x0f;
 543         if (type < ARRAY_SIZE(floppy_types))
 544                 seq_printf(seq, "%s\n", floppy_types[type]);
 545         else
 546                 seq_printf(seq, "%d (unknown)\n", type);
 547
 548         seq_printf(seq, "HD 0 type      : ");
 549         type = nvram[4] >> 4;
 550         if (type)
 551                 seq_printf(seq, "%02x\n", type == 0x0f ? nvram[11] : type);
 552         else
 553                 seq_printf(seq, "none\n");
 554
 555         seq_printf(seq, "HD 1 type      : ");
 556         type = nvram[4] & 0x0f;
 557         if (type)
 558                 seq_printf(seq, "%02x\n", type == 0x0f ? nvram[12] : type);
 559         else
 560                 seq_printf(seq, "none\n");
 561
 562         seq_printf(seq, "HD type 48 data: %d/%d/%d C/H/S, precomp %d, lz %d\n",
 563             nvram[18] | (nvram[19] << 8),
 564             nvram[20], nvram[25],
 565             nvram[21] | (nvram[22] << 8), nvram[23] | (nvram[24] << 8));
 566         seq_printf(seq, "HD type 49 data: %d/%d/%d C/H/S, precomp %d, lz %d\n",
 567             nvram[39] | (nvram[40] << 8),
 568             nvram[41], nvram[46],
 569             nvram[42] | (nvram[43] << 8), nvram[44] | (nvram[45] << 8));
 570
 571         seq_printf(seq, "DOS base memory: %d kB\n", nvram[7] | (nvram[8] << 8));
 572         seq_printf(seq, "Extended memory: %d kB (configured), %d kB (tested)\n",
 573             nvram[9] | (nvram[10] << 8), nvram[34] | (nvram[35] << 8));
 574
 575         seq_printf(seq, "Gfx adapter    : %s\n",
 576             gfx_types[(nvram[6] >> 4) & 3]);
 577
 578         seq_printf(seq, "FPU            : %sinstalled\n",
 579             (nvram[6] & 2) ? "" : "not ");
 580
 581         return;
 582 }
 583 #endif
 584
 585 #endif /* MACH == PC */
 586
 587 #if MACH == ATARI
 588
 589 static int atari_check_checksum(void)
 590 {
 591         int i;
 592         unsigned char sum = 0;
 593
 594         for (i = ATARI_CKS_RANGE_START; i <= ATARI_CKS_RANGE_END; ++i)
 595                 sum += __nvram_read_byte(i);
 596         return (__nvram_read_byte(ATARI_CKS_LOC) == (~sum & 0xff)) &&
 597             (__nvram_read_byte(ATARI_CKS_LOC + 1) == (sum & 0xff));
 598 }
 599
 600 static void atari_set_checksum(void)
 601 {
 602         int i;
 603         unsigned char sum = 0;
 604
 605         for (i = ATARI_CKS_RANGE_START; i <= ATARI_CKS_RANGE_END; ++i)
 606                 sum += __nvram_read_byte(i);
 607         __nvram_write_byte(~sum, ATARI_CKS_LOC);
 608         __nvram_write_byte(sum, ATARI_CKS_LOC + 1);
 609 }
 610
 611 #ifdef CONFIG_PROC_FS
 612
 613 static struct {
 614         unsigned char val;
 615         char *name;
 616 } boot_prefs[] = {
 617         { 0x80, "TOS" },
 618         { 0x40, "ASV" },
 619         { 0x20, "NetBSD (?)" },
 620         { 0x10, "Linux" },
 621         { 0x00, "unspecified" }
 622 };
 623
 624 static char *languages[] = {
 625         "English (US)",
 626         "German",
 627         "French",
 628         "English (UK)",
 629         "Spanish",
 630         "Italian",
 631         "6 (undefined)",
 632         "Swiss (French)",
 633         "Swiss (German)"
 634 };
 635
 636 static char *dateformat[] = {
 637         "MM%cDD%cYY",
 638         "DD%cMM%cYY",
 639         "YY%cMM%cDD",
 640         "YY%cDD%cMM",
 641         "4 (undefined)",
 642         "5 (undefined)",
 643         "6 (undefined)",
 644         "7 (undefined)"
 645 };
 646
 647 static char *colors[] = {
 648         "2", "4", "16", "256", "65536", "??", "??", "??"
 649 };
 650
 651 static void atari_proc_infos(unsigned char *nvram, struct seq_file *seq,
 652                                                                 void *offset)
 653 {
 654         int checksum = nvram_check_checksum();
 655         int i;
 656         unsigned vmode;
 657
 658         seq_printf(seq, "Checksum status  : %svalid\n", checksum ? "" : "not ");
 659
 660         seq_printf(seq, "Boot preference  : ");
 661         for (i = ARRAY_SIZE(boot_prefs) - 1; i >= 0; --i) {
 662                 if (nvram[1] == boot_prefs[i].val) {
 663                         seq_printf(seq, "%s\n", boot_prefs[i].name);
 664                         break;
 665                 }
 666         }
 667         if (i < 0)
 668                 seq_printf(seq, "0x%02x (undefined)\n", nvram[1]);
 669
 670         seq_printf(seq, "SCSI arbitration : %s\n",
 671             (nvram[16] & 0x80) ? "on" : "off");
 672         seq_printf(seq, "SCSI host ID     : ");
 673         if (nvram[16] & 0x80)
 674                 seq_printf(seq, "%d\n", nvram[16] & 7);
 675         else
 676                 seq_printf(seq, "n/a\n");
 677
 678         /* the following entries are defined only for the Falcon */
 679         if ((atari_mch_cookie >> 16) != ATARI_MCH_FALCON)
 680                 return;
 681
 682         seq_printf(seq, "OS language      : ");
 683         if (nvram[6] < ARRAY_SIZE(languages))
 684                 seq_printf(seq, "%s\n", languages[nvram[6]]);
 685         else
 686                 seq_printf(seq, "%u (undefined)\n", nvram[6]);
 687         seq_printf(seq, "Keyboard language: ");
 688         if (nvram[7] < ARRAY_SIZE(languages))
 689                 seq_printf(seq, "%s\n", languages[nvram[7]]);
 690         else
 691                 seq_printf(seq, "%u (undefined)\n", nvram[7]);
 692         seq_printf(seq, "Date format      : ");
 693         seq_printf(seq, dateformat[nvram[8] & 7],
 694             nvram[9] ? nvram[9] : '/', nvram[9] ? nvram[9] : '/');
 695         seq_printf(seq, ", %dh clock\n", nvram[8] & 16 ? 24 : 12);
 696         seq_printf(seq, "Boot delay       : ");
 697         if (nvram[10] == 0)
 698                 seq_printf(seq, "default");
 699         else
 700                 seq_printf(seq, "%ds%s\n", nvram[10],
 701                     nvram[10] < 8 ? ", no memory test" : "");
 702
 703         vmode = (nvram[14] << 8) || nvram[15];
 704         seq_printf(seq,
 705             "Video mode       : %s colors, %d columns, %s %s monitor\n",
 706             colors[vmode & 7],
 707             vmode & 8 ? 80 : 40,
 708             vmode & 16 ? "VGA" : "TV", vmode & 32 ? "PAL" : "NTSC");
 709         seq_printf(seq, "                   %soverscan, compat. mode %s%s\n",
 710             vmode & 64 ? "" : "no ",
 711             vmode & 128 ? "on" : "off",
 712             vmode & 256 ?
 713             (vmode & 16 ? ", line doubling" : ", half screen") : "");
 714
 715         return;
 716 }
 717 #endif
 718
 719 #endif /* MACH == ATARI */
 720
 721 MODULE_LICENSE("GPL");
 722 MODULE_ALIAS_MISCDEV(NVRAM_MINOR);