x86: hpet: provide separate functions to stop and start the counter
[linux-2.6/linux-acpi-2.6/ibm-acpi-2.6.git] / drivers / char / nvram.c
blob88cee4099be940c294127d0a172996d90c597912
1 /*
2 * CMOS/NV-RAM driver for Linux
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)
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).
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).
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!)
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.
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
38 #define NVRAM_VERSION "1.3"
40 #include <linux/module.h>
41 #include <linux/smp_lock.h>
42 #include <linux/nvram.h>
44 #define PC 1
45 #define ATARI 2
47 /* select machine configuration */
48 #if defined(CONFIG_ATARI)
49 # define MACH ATARI
50 #elif defined(__i386__) || defined(__x86_64__) || defined(__arm__) /* and ?? */
51 # define MACH PC
52 #else
53 # error Cannot build nvram driver for this machine configuration.
54 #endif
56 #if MACH == PC
58 /* RTC in a PC */
59 #define CHECK_DRIVER_INIT() 1
61 /* On PCs, the checksum is built only over bytes 2..31 */
62 #define PC_CKS_RANGE_START 2
63 #define PC_CKS_RANGE_END 31
64 #define PC_CKS_LOC 32
65 #define NVRAM_BYTES (128-NVRAM_FIRST_BYTE)
67 #define mach_check_checksum pc_check_checksum
68 #define mach_set_checksum pc_set_checksum
69 #define mach_proc_infos pc_proc_infos
71 #endif
73 #if MACH == ATARI
75 /* Special parameters for RTC in Atari machines */
76 #include <asm/atarihw.h>
77 #include <asm/atariints.h>
78 #define RTC_PORT(x) (TT_RTC_BAS + 2*(x))
79 #define CHECK_DRIVER_INIT() (MACH_IS_ATARI && ATARIHW_PRESENT(TT_CLK))
81 #define NVRAM_BYTES 50
83 /* On Ataris, the checksum is over all bytes except the checksum bytes
84 * themselves; these are at the very end */
85 #define ATARI_CKS_RANGE_START 0
86 #define ATARI_CKS_RANGE_END 47
87 #define ATARI_CKS_LOC 48
89 #define mach_check_checksum atari_check_checksum
90 #define mach_set_checksum atari_set_checksum
91 #define mach_proc_infos atari_proc_infos
93 #endif
95 /* Note that *all* calls to CMOS_READ and CMOS_WRITE must be done with
96 * rtc_lock held. Due to the index-port/data-port design of the RTC, we
97 * don't want two different things trying to get to it at once. (e.g. the
98 * periodic 11 min sync from time.c vs. this driver.)
101 #include <linux/types.h>
102 #include <linux/errno.h>
103 #include <linux/miscdevice.h>
104 #include <linux/slab.h>
105 #include <linux/ioport.h>
106 #include <linux/fcntl.h>
107 #include <linux/mc146818rtc.h>
108 #include <linux/init.h>
109 #include <linux/proc_fs.h>
110 #include <linux/seq_file.h>
111 #include <linux/spinlock.h>
112 #include <linux/io.h>
113 #include <linux/uaccess.h>
115 #include <asm/system.h>
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 */
123 static int mach_check_checksum(void);
124 static void mach_set_checksum(void);
126 #ifdef CONFIG_PROC_FS
127 static void mach_proc_infos(unsigned char *contents, struct seq_file *seq,
128 void *offset);
129 #endif
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).
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.
142 unsigned char __nvram_read_byte(int i)
144 return CMOS_READ(NVRAM_FIRST_BYTE + i);
146 EXPORT_SYMBOL(__nvram_read_byte);
148 unsigned char nvram_read_byte(int i)
150 unsigned long flags;
151 unsigned char c;
153 spin_lock_irqsave(&rtc_lock, flags);
154 c = __nvram_read_byte(i);
155 spin_unlock_irqrestore(&rtc_lock, flags);
156 return c;
158 EXPORT_SYMBOL(nvram_read_byte);
160 /* This races nicely with trying to read with checksum checking (nvram_read) */
161 void __nvram_write_byte(unsigned char c, int i)
163 CMOS_WRITE(c, NVRAM_FIRST_BYTE + i);
165 EXPORT_SYMBOL(__nvram_write_byte);
167 void nvram_write_byte(unsigned char c, int i)
169 unsigned long flags;
171 spin_lock_irqsave(&rtc_lock, flags);
172 __nvram_write_byte(c, i);
173 spin_unlock_irqrestore(&rtc_lock, flags);
175 EXPORT_SYMBOL(nvram_write_byte);
177 int __nvram_check_checksum(void)
179 return mach_check_checksum();
181 EXPORT_SYMBOL(__nvram_check_checksum);
183 int nvram_check_checksum(void)
185 unsigned long flags;
186 int rv;
188 spin_lock_irqsave(&rtc_lock, flags);
189 rv = __nvram_check_checksum();
190 spin_unlock_irqrestore(&rtc_lock, flags);
191 return rv;
193 EXPORT_SYMBOL(nvram_check_checksum);
195 static void __nvram_set_checksum(void)
197 mach_set_checksum();
200 #if 0
201 void nvram_set_checksum(void)
203 unsigned long flags;
205 spin_lock_irqsave(&rtc_lock, flags);
206 __nvram_set_checksum();
207 spin_unlock_irqrestore(&rtc_lock, flags);
209 #endif /* 0 */
212 * The are the file operation function for user access to /dev/nvram
215 static loff_t nvram_llseek(struct file *file, loff_t offset, int origin)
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;
229 unlock_kernel();
230 return (offset >= 0) ? (file->f_pos = offset) : -EINVAL;
233 static ssize_t nvram_read(struct file *file, char __user *buf,
234 size_t count, loff_t *ppos)
236 unsigned char contents[NVRAM_BYTES];
237 unsigned i = *ppos;
238 unsigned char *tmp;
240 spin_lock_irq(&rtc_lock);
242 if (!__nvram_check_checksum())
243 goto checksum_err;
245 for (tmp = contents; count-- > 0 && i < NVRAM_BYTES; ++i, ++tmp)
246 *tmp = __nvram_read_byte(i);
248 spin_unlock_irq(&rtc_lock);
250 if (copy_to_user(buf, contents, tmp - contents))
251 return -EFAULT;
253 *ppos = i;
255 return tmp - contents;
257 checksum_err:
258 spin_unlock_irq(&rtc_lock);
259 return -EIO;
262 static ssize_t nvram_write(struct file *file, const char __user *buf,
263 size_t count, loff_t *ppos)
265 unsigned char contents[NVRAM_BYTES];
266 unsigned i = *ppos;
267 unsigned char *tmp;
268 int len;
270 len = (NVRAM_BYTES - i) < count ? (NVRAM_BYTES - i) : count;
271 if (copy_from_user(contents, buf, len))
272 return -EFAULT;
274 spin_lock_irq(&rtc_lock);
276 if (!__nvram_check_checksum())
277 goto checksum_err;
279 for (tmp = contents; count-- > 0 && i < NVRAM_BYTES; ++i, ++tmp)
280 __nvram_write_byte(*tmp, i);
282 __nvram_set_checksum();
284 spin_unlock_irq(&rtc_lock);
286 *ppos = i;
288 return tmp - contents;
290 checksum_err:
291 spin_unlock_irq(&rtc_lock);
292 return -EIO;
295 static int nvram_ioctl(struct inode *inode, struct file *file,
296 unsigned int cmd, unsigned long arg)
298 int i;
300 switch (cmd) {
302 case NVRAM_INIT:
303 /* initialize NVRAM contents and checksum */
304 if (!capable(CAP_SYS_ADMIN))
305 return -EACCES;
307 spin_lock_irq(&rtc_lock);
309 for (i = 0; i < NVRAM_BYTES; ++i)
310 __nvram_write_byte(0, i);
311 __nvram_set_checksum();
313 spin_unlock_irq(&rtc_lock);
314 return 0;
316 case NVRAM_SETCKS:
317 /* just set checksum, contents unchanged (maybe useful after
318 * checksum garbaged somehow...) */
319 if (!capable(CAP_SYS_ADMIN))
320 return -EACCES;
322 spin_lock_irq(&rtc_lock);
323 __nvram_set_checksum();
324 spin_unlock_irq(&rtc_lock);
325 return 0;
327 default:
328 return -ENOTTY;
332 static int nvram_open(struct inode *inode, struct file *file)
334 lock_kernel();
335 spin_lock(&nvram_state_lock);
337 if ((nvram_open_cnt && (file->f_flags & O_EXCL)) ||
338 (nvram_open_mode & NVRAM_EXCL) ||
339 ((file->f_mode & FMODE_WRITE) && (nvram_open_mode & NVRAM_WRITE))) {
340 spin_unlock(&nvram_state_lock);
341 unlock_kernel();
342 return -EBUSY;
345 if (file->f_flags & O_EXCL)
346 nvram_open_mode |= NVRAM_EXCL;
347 if (file->f_mode & FMODE_WRITE)
348 nvram_open_mode |= NVRAM_WRITE;
349 nvram_open_cnt++;
351 spin_unlock(&nvram_state_lock);
352 unlock_kernel();
354 return 0;
357 static int nvram_release(struct inode *inode, struct file *file)
359 spin_lock(&nvram_state_lock);
361 nvram_open_cnt--;
363 /* if only one instance is open, clear the EXCL bit */
364 if (nvram_open_mode & NVRAM_EXCL)
365 nvram_open_mode &= ~NVRAM_EXCL;
366 if (file->f_mode & FMODE_WRITE)
367 nvram_open_mode &= ~NVRAM_WRITE;
369 spin_unlock(&nvram_state_lock);
371 return 0;
374 #ifndef CONFIG_PROC_FS
375 static int nvram_add_proc_fs(void)
377 return 0;
380 #else
382 static int nvram_proc_read(struct seq_file *seq, void *offset)
384 unsigned char contents[NVRAM_BYTES];
385 int i = 0;
387 spin_lock_irq(&rtc_lock);
388 for (i = 0; i < NVRAM_BYTES; ++i)
389 contents[i] = __nvram_read_byte(i);
390 spin_unlock_irq(&rtc_lock);
392 mach_proc_infos(contents, seq, offset);
394 return 0;
397 static int nvram_proc_open(struct inode *inode, struct file *file)
399 return single_open(file, nvram_proc_read, NULL);
402 static const struct file_operations nvram_proc_fops = {
403 .owner = THIS_MODULE,
404 .open = nvram_proc_open,
405 .read = seq_read,
406 .llseek = seq_lseek,
407 .release = single_release,
410 static int nvram_add_proc_fs(void)
412 if (!proc_create("driver/nvram", 0, NULL, &nvram_proc_fops))
413 return -ENOMEM;
414 return 0;
417 #endif /* CONFIG_PROC_FS */
419 static const struct file_operations nvram_fops = {
420 .owner = THIS_MODULE,
421 .llseek = nvram_llseek,
422 .read = nvram_read,
423 .write = nvram_write,
424 .ioctl = nvram_ioctl,
425 .open = nvram_open,
426 .release = nvram_release,
429 static struct miscdevice nvram_dev = {
430 NVRAM_MINOR,
431 "nvram",
432 &nvram_fops
435 static int __init nvram_init(void)
437 int ret;
439 /* First test whether the driver should init at all */
440 if (!CHECK_DRIVER_INIT())
441 return -ENODEV;
443 ret = misc_register(&nvram_dev);
444 if (ret) {
445 printk(KERN_ERR "nvram: can't misc_register on minor=%d\n",
446 NVRAM_MINOR);
447 goto out;
449 ret = nvram_add_proc_fs();
450 if (ret) {
451 printk(KERN_ERR "nvram: can't create /proc/driver/nvram\n");
452 goto outmisc;
454 ret = 0;
455 printk(KERN_INFO "Non-volatile memory driver v" NVRAM_VERSION "\n");
456 out:
457 return ret;
458 outmisc:
459 misc_deregister(&nvram_dev);
460 goto out;
463 static void __exit nvram_cleanup_module(void)
465 remove_proc_entry("driver/nvram", NULL);
466 misc_deregister(&nvram_dev);
469 module_init(nvram_init);
470 module_exit(nvram_cleanup_module);
473 * Machine specific functions
476 #if MACH == PC
478 static int pc_check_checksum(void)
480 int i;
481 unsigned short sum = 0;
482 unsigned short expect;
484 for (i = PC_CKS_RANGE_START; i <= PC_CKS_RANGE_END; ++i)
485 sum += __nvram_read_byte(i);
486 expect = __nvram_read_byte(PC_CKS_LOC)<<8 |
487 __nvram_read_byte(PC_CKS_LOC+1);
488 return (sum & 0xffff) == expect;
491 static void pc_set_checksum(void)
493 int i;
494 unsigned short sum = 0;
496 for (i = PC_CKS_RANGE_START; i <= PC_CKS_RANGE_END; ++i)
497 sum += __nvram_read_byte(i);
498 __nvram_write_byte(sum >> 8, PC_CKS_LOC);
499 __nvram_write_byte(sum & 0xff, PC_CKS_LOC + 1);
502 #ifdef CONFIG_PROC_FS
504 static char *floppy_types[] = {
505 "none", "5.25'' 360k", "5.25'' 1.2M", "3.5'' 720k", "3.5'' 1.44M",
506 "3.5'' 2.88M", "3.5'' 2.88M"
509 static char *gfx_types[] = {
510 "EGA, VGA, ... (with BIOS)",
511 "CGA (40 cols)",
512 "CGA (80 cols)",
513 "monochrome",
516 static void pc_proc_infos(unsigned char *nvram, struct seq_file *seq,
517 void *offset)
519 int checksum;
520 int type;
522 spin_lock_irq(&rtc_lock);
523 checksum = __nvram_check_checksum();
524 spin_unlock_irq(&rtc_lock);
526 seq_printf(seq, "Checksum status: %svalid\n", checksum ? "" : "not ");
528 seq_printf(seq, "# floppies : %d\n",
529 (nvram[6] & 1) ? (nvram[6] >> 6) + 1 : 0);
530 seq_printf(seq, "Floppy 0 type : ");
531 type = nvram[2] >> 4;
532 if (type < ARRAY_SIZE(floppy_types))
533 seq_printf(seq, "%s\n", floppy_types[type]);
534 else
535 seq_printf(seq, "%d (unknown)\n", type);
536 seq_printf(seq, "Floppy 1 type : ");
537 type = nvram[2] & 0x0f;
538 if (type < ARRAY_SIZE(floppy_types))
539 seq_printf(seq, "%s\n", floppy_types[type]);
540 else
541 seq_printf(seq, "%d (unknown)\n", type);
543 seq_printf(seq, "HD 0 type : ");
544 type = nvram[4] >> 4;
545 if (type)
546 seq_printf(seq, "%02x\n", type == 0x0f ? nvram[11] : type);
547 else
548 seq_printf(seq, "none\n");
550 seq_printf(seq, "HD 1 type : ");
551 type = nvram[4] & 0x0f;
552 if (type)
553 seq_printf(seq, "%02x\n", type == 0x0f ? nvram[12] : type);
554 else
555 seq_printf(seq, "none\n");
557 seq_printf(seq, "HD type 48 data: %d/%d/%d C/H/S, precomp %d, lz %d\n",
558 nvram[18] | (nvram[19] << 8),
559 nvram[20], nvram[25],
560 nvram[21] | (nvram[22] << 8), nvram[23] | (nvram[24] << 8));
561 seq_printf(seq, "HD type 49 data: %d/%d/%d C/H/S, precomp %d, lz %d\n",
562 nvram[39] | (nvram[40] << 8),
563 nvram[41], nvram[46],
564 nvram[42] | (nvram[43] << 8), nvram[44] | (nvram[45] << 8));
566 seq_printf(seq, "DOS base memory: %d kB\n", nvram[7] | (nvram[8] << 8));
567 seq_printf(seq, "Extended memory: %d kB (configured), %d kB (tested)\n",
568 nvram[9] | (nvram[10] << 8), nvram[34] | (nvram[35] << 8));
570 seq_printf(seq, "Gfx adapter : %s\n",
571 gfx_types[(nvram[6] >> 4) & 3]);
573 seq_printf(seq, "FPU : %sinstalled\n",
574 (nvram[6] & 2) ? "" : "not ");
576 return;
578 #endif
580 #endif /* MACH == PC */
582 #if MACH == ATARI
584 static int atari_check_checksum(void)
586 int i;
587 unsigned char sum = 0;
589 for (i = ATARI_CKS_RANGE_START; i <= ATARI_CKS_RANGE_END; ++i)
590 sum += __nvram_read_byte(i);
591 return (__nvram_read_byte(ATARI_CKS_LOC) == (~sum & 0xff)) &&
592 (__nvram_read_byte(ATARI_CKS_LOC + 1) == (sum & 0xff));
595 static void atari_set_checksum(void)
597 int i;
598 unsigned char sum = 0;
600 for (i = ATARI_CKS_RANGE_START; i <= ATARI_CKS_RANGE_END; ++i)
601 sum += __nvram_read_byte(i);
602 __nvram_write_byte(~sum, ATARI_CKS_LOC);
603 __nvram_write_byte(sum, ATARI_CKS_LOC + 1);
606 #ifdef CONFIG_PROC_FS
608 static struct {
609 unsigned char val;
610 char *name;
611 } boot_prefs[] = {
612 { 0x80, "TOS" },
613 { 0x40, "ASV" },
614 { 0x20, "NetBSD (?)" },
615 { 0x10, "Linux" },
616 { 0x00, "unspecified" }
619 static char *languages[] = {
620 "English (US)",
621 "German",
622 "French",
623 "English (UK)",
624 "Spanish",
625 "Italian",
626 "6 (undefined)",
627 "Swiss (French)",
628 "Swiss (German)"
631 static char *dateformat[] = {
632 "MM%cDD%cYY",
633 "DD%cMM%cYY",
634 "YY%cMM%cDD",
635 "YY%cDD%cMM",
636 "4 (undefined)",
637 "5 (undefined)",
638 "6 (undefined)",
639 "7 (undefined)"
642 static char *colors[] = {
643 "2", "4", "16", "256", "65536", "??", "??", "??"
646 static void atari_proc_infos(unsigned char *nvram, struct seq_file *seq,
647 void *offset)
649 int checksum = nvram_check_checksum();
650 int i;
651 unsigned vmode;
653 seq_printf(seq, "Checksum status : %svalid\n", checksum ? "" : "not ");
655 seq_printf(seq, "Boot preference : ");
656 for (i = ARRAY_SIZE(boot_prefs) - 1; i >= 0; --i) {
657 if (nvram[1] == boot_prefs[i].val) {
658 seq_printf(seq, "%s\n", boot_prefs[i].name);
659 break;
662 if (i < 0)
663 seq_printf(seq, "0x%02x (undefined)\n", nvram[1]);
665 seq_printf(seq, "SCSI arbitration : %s\n",
666 (nvram[16] & 0x80) ? "on" : "off");
667 seq_printf(seq, "SCSI host ID : ");
668 if (nvram[16] & 0x80)
669 seq_printf(seq, "%d\n", nvram[16] & 7);
670 else
671 seq_printf(seq, "n/a\n");
673 /* the following entries are defined only for the Falcon */
674 if ((atari_mch_cookie >> 16) != ATARI_MCH_FALCON)
675 return;
677 seq_printf(seq, "OS language : ");
678 if (nvram[6] < ARRAY_SIZE(languages))
679 seq_printf(seq, "%s\n", languages[nvram[6]]);
680 else
681 seq_printf(seq, "%u (undefined)\n", nvram[6]);
682 seq_printf(seq, "Keyboard language: ");
683 if (nvram[7] < ARRAY_SIZE(languages))
684 seq_printf(seq, "%s\n", languages[nvram[7]]);
685 else
686 seq_printf(seq, "%u (undefined)\n", nvram[7]);
687 seq_printf(seq, "Date format : ");
688 seq_printf(seq, dateformat[nvram[8] & 7],
689 nvram[9] ? nvram[9] : '/', nvram[9] ? nvram[9] : '/');
690 seq_printf(seq, ", %dh clock\n", nvram[8] & 16 ? 24 : 12);
691 seq_printf(seq, "Boot delay : ");
692 if (nvram[10] == 0)
693 seq_printf(seq, "default");
694 else
695 seq_printf(seq, "%ds%s\n", nvram[10],
696 nvram[10] < 8 ? ", no memory test" : "");
698 vmode = (nvram[14] << 8) || nvram[15];
699 seq_printf(seq,
700 "Video mode : %s colors, %d columns, %s %s monitor\n",
701 colors[vmode & 7],
702 vmode & 8 ? 80 : 40,
703 vmode & 16 ? "VGA" : "TV", vmode & 32 ? "PAL" : "NTSC");
704 seq_printf(seq, " %soverscan, compat. mode %s%s\n",
705 vmode & 64 ? "" : "no ",
706 vmode & 128 ? "on" : "off",
707 vmode & 256 ?
708 (vmode & 16 ? ", line doubling" : ", half screen") : "");
710 return;
712 #endif
714 #endif /* MACH == ATARI */
716 MODULE_LICENSE("GPL");
717 MODULE_ALIAS_MISCDEV(NVRAM_MINOR);