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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/mutex.h>
113
114#include <asm/system.h>
115
116static DEFINE_MUTEX(nvram_mutex);
117static DEFINE_SPINLOCK(nvram_state_lock);
118static int nvram_open_cnt; /* #times opened */
119static 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
123static int mach_check_checksum(void);
124static void mach_set_checksum(void);
125
126#ifdef CONFIG_PROC_FS
127static 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
142unsigned char __nvram_read_byte(int i)
143{
144 return CMOS_READ(NVRAM_FIRST_BYTE + i);
145}
146EXPORT_SYMBOL(__nvram_read_byte);
147
148unsigned 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}
158EXPORT_SYMBOL(nvram_read_byte);
159
160/* This races nicely with trying to read with checksum checking (nvram_read) */
161void __nvram_write_byte(unsigned char c, int i)
162{
163 CMOS_WRITE(c, NVRAM_FIRST_BYTE + i);
164}
165EXPORT_SYMBOL(__nvram_write_byte);
166
167void 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}
175EXPORT_SYMBOL(nvram_write_byte);
176
177int __nvram_check_checksum(void)
178{
179 return mach_check_checksum();
180}
181EXPORT_SYMBOL(__nvram_check_checksum);
182
183int 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}
193EXPORT_SYMBOL(nvram_check_checksum);
194
195static void __nvram_set_checksum(void)
196{
197 mach_set_checksum();
198}
199
200#if 0
201void 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
215static loff_t nvram_llseek(struct file *file, loff_t offset, int origin)
216{
217 switch (origin) {
218 case 0:
219 /* nothing to do */
220 break;
221 case 1:
222 offset += file->f_pos;
223 break;
224 case 2:
225 offset += NVRAM_BYTES;
226 break;
227 default:
228 return -EINVAL;
229 }
230
231 return (offset >= 0) ? (file->f_pos = offset) : -EINVAL;
232}
233
234static ssize_t nvram_read(struct file *file, char __user *buf,
235 size_t count, loff_t *ppos)
236{
237 unsigned char contents[NVRAM_BYTES];
238 unsigned i = *ppos;
239 unsigned char *tmp;
240
241 spin_lock_irq(&rtc_lock);
242
243 if (!__nvram_check_checksum())
244 goto checksum_err;
245
246 for (tmp = contents; count-- > 0 && i < NVRAM_BYTES; ++i, ++tmp)
247 *tmp = __nvram_read_byte(i);
248
249 spin_unlock_irq(&rtc_lock);
250
251 if (copy_to_user(buf, contents, tmp - contents))
252 return -EFAULT;
253
254 *ppos = i;
255
256 return tmp - contents;
257
258checksum_err:
259 spin_unlock_irq(&rtc_lock);
260 return -EIO;
261}
262
263static ssize_t nvram_write(struct file *file, const char __user *buf,
264 size_t count, loff_t *ppos)
265{
266 unsigned char contents[NVRAM_BYTES];
267 unsigned i = *ppos;
268 unsigned char *tmp;
269
270 if (i >= NVRAM_BYTES)
271 return 0; /* Past EOF */
272
273 if (count > NVRAM_BYTES - i)
274 count = NVRAM_BYTES - i;
275 if (count > NVRAM_BYTES)
276 return -EFAULT; /* Can't happen, but prove it to gcc */
277
278 if (copy_from_user(contents, buf, count))
279 return -EFAULT;
280
281 spin_lock_irq(&rtc_lock);
282
283 if (!__nvram_check_checksum())
284 goto checksum_err;
285
286 for (tmp = contents; count--; ++i, ++tmp)
287 __nvram_write_byte(*tmp, i);
288
289 __nvram_set_checksum();
290
291 spin_unlock_irq(&rtc_lock);
292
293 *ppos = i;
294
295 return tmp - contents;
296
297checksum_err:
298 spin_unlock_irq(&rtc_lock);
299 return -EIO;
300}
301
302static long nvram_ioctl(struct file *file, unsigned int cmd,
303 unsigned long arg)
304{
305 int i;
306
307 switch (cmd) {
308
309 case NVRAM_INIT:
310 /* initialize NVRAM contents and checksum */
311 if (!capable(CAP_SYS_ADMIN))
312 return -EACCES;
313
314 mutex_lock(&nvram_mutex);
315 spin_lock_irq(&rtc_lock);
316
317 for (i = 0; i < NVRAM_BYTES; ++i)
318 __nvram_write_byte(0, i);
319 __nvram_set_checksum();
320
321 spin_unlock_irq(&rtc_lock);
322 mutex_unlock(&nvram_mutex);
323 return 0;
324
325 case NVRAM_SETCKS:
326 /* just set checksum, contents unchanged (maybe useful after
327 * checksum garbaged somehow...) */
328 if (!capable(CAP_SYS_ADMIN))
329 return -EACCES;
330
331 mutex_lock(&nvram_mutex);
332 spin_lock_irq(&rtc_lock);
333 __nvram_set_checksum();
334 spin_unlock_irq(&rtc_lock);
335 mutex_unlock(&nvram_mutex);
336 return 0;
337
338 default:
339 return -ENOTTY;
340 }
341}
342
343static int nvram_open(struct inode *inode, struct file *file)
344{
345 spin_lock(&nvram_state_lock);
346
347 if ((nvram_open_cnt && (file->f_flags & O_EXCL)) ||
348 (nvram_open_mode & NVRAM_EXCL) ||
349 ((file->f_mode & FMODE_WRITE) && (nvram_open_mode & NVRAM_WRITE))) {
350 spin_unlock(&nvram_state_lock);
351 return -EBUSY;
352 }
353
354 if (file->f_flags & O_EXCL)
355 nvram_open_mode |= NVRAM_EXCL;
356 if (file->f_mode & FMODE_WRITE)
357 nvram_open_mode |= NVRAM_WRITE;
358 nvram_open_cnt++;
359
360 spin_unlock(&nvram_state_lock);
361
362 return 0;
363}
364
365static int nvram_release(struct inode *inode, struct file *file)
366{
367 spin_lock(&nvram_state_lock);
368
369 nvram_open_cnt--;
370
371 /* if only one instance is open, clear the EXCL bit */
372 if (nvram_open_mode & NVRAM_EXCL)
373 nvram_open_mode &= ~NVRAM_EXCL;
374 if (file->f_mode & FMODE_WRITE)
375 nvram_open_mode &= ~NVRAM_WRITE;
376
377 spin_unlock(&nvram_state_lock);
378
379 return 0;
380}
381
382#ifndef CONFIG_PROC_FS
383static int nvram_add_proc_fs(void)
384{
385 return 0;
386}
387
388#else
389
390static int nvram_proc_read(struct seq_file *seq, void *offset)
391{
392 unsigned char contents[NVRAM_BYTES];
393 int i = 0;
394
395 spin_lock_irq(&rtc_lock);
396 for (i = 0; i < NVRAM_BYTES; ++i)
397 contents[i] = __nvram_read_byte(i);
398 spin_unlock_irq(&rtc_lock);
399
400 mach_proc_infos(contents, seq, offset);
401
402 return 0;
403}
404
405static int nvram_proc_open(struct inode *inode, struct file *file)
406{
407 return single_open(file, nvram_proc_read, NULL);
408}
409
410static const struct file_operations nvram_proc_fops = {
411 .owner = THIS_MODULE,
412 .open = nvram_proc_open,
413 .read = seq_read,
414 .llseek = seq_lseek,
415 .release = single_release,
416};
417
418static int nvram_add_proc_fs(void)
419{
420 if (!proc_create("driver/nvram", 0, NULL, &nvram_proc_fops))
421 return -ENOMEM;
422 return 0;
423}
424
425#endif /* CONFIG_PROC_FS */
426
427static const struct file_operations nvram_fops = {
428 .owner = THIS_MODULE,
429 .llseek = nvram_llseek,
430 .read = nvram_read,
431 .write = nvram_write,
432 .unlocked_ioctl = nvram_ioctl,
433 .open = nvram_open,
434 .release = nvram_release,
435};
436
437static struct miscdevice nvram_dev = {
438 NVRAM_MINOR,
439 "nvram",
440 &nvram_fops
441};
442
443static int __init nvram_init(void)
444{
445 int ret;
446
447 /* First test whether the driver should init at all */
448 if (!CHECK_DRIVER_INIT())
449 return -ENODEV;
450
451 ret = misc_register(&nvram_dev);
452 if (ret) {
453 printk(KERN_ERR "nvram: can't misc_register on minor=%d\n",
454 NVRAM_MINOR);
455 goto out;
456 }
457 ret = nvram_add_proc_fs();
458 if (ret) {
459 printk(KERN_ERR "nvram: can't create /proc/driver/nvram\n");
460 goto outmisc;
461 }
462 ret = 0;
463 printk(KERN_INFO "Non-volatile memory driver v" NVRAM_VERSION "\n");
464out:
465 return ret;
466outmisc:
467 misc_deregister(&nvram_dev);
468 goto out;
469}
470
471static void __exit nvram_cleanup_module(void)
472{
473 remove_proc_entry("driver/nvram", NULL);
474 misc_deregister(&nvram_dev);
475}
476
477module_init(nvram_init);
478module_exit(nvram_cleanup_module);
479
480/*
481 * Machine specific functions
482 */
483
484#if MACH == PC
485
486static int 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
499static void pc_set_checksum(void)
500{
501 int i;
502 unsigned short sum = 0;
503
504 for (i = PC_CKS_RANGE_START; i <= PC_CKS_RANGE_END; ++i)
505 sum += __nvram_read_byte(i);
506 __nvram_write_byte(sum >> 8, PC_CKS_LOC);
507 __nvram_write_byte(sum & 0xff, PC_CKS_LOC + 1);
508}
509
510#ifdef CONFIG_PROC_FS
511
512static char *floppy_types[] = {
513 "none", "5.25'' 360k", "5.25'' 1.2M", "3.5'' 720k", "3.5'' 1.44M",
514 "3.5'' 2.88M", "3.5'' 2.88M"
515};
516
517static char *gfx_types[] = {
518 "EGA, VGA, ... (with BIOS)",
519 "CGA (40 cols)",
520 "CGA (80 cols)",
521 "monochrome",
522};
523
524static void pc_proc_infos(unsigned char *nvram, struct seq_file *seq,
525 void *offset)
526{
527 int checksum;
528 int type;
529
530 spin_lock_irq(&rtc_lock);
531 checksum = __nvram_check_checksum();
532 spin_unlock_irq(&rtc_lock);
533
534 seq_printf(seq, "Checksum status: %svalid\n", checksum ? "" : "not ");
535
536 seq_printf(seq, "# floppies : %d\n",
537 (nvram[6] & 1) ? (nvram[6] >> 6) + 1 : 0);
538 seq_printf(seq, "Floppy 0 type : ");
539 type = nvram[2] >> 4;
540 if (type < ARRAY_SIZE(floppy_types))
541 seq_printf(seq, "%s\n", floppy_types[type]);
542 else
543 seq_printf(seq, "%d (unknown)\n", type);
544 seq_printf(seq, "Floppy 1 type : ");
545 type = nvram[2] & 0x0f;
546 if (type < ARRAY_SIZE(floppy_types))
547 seq_printf(seq, "%s\n", floppy_types[type]);
548 else
549 seq_printf(seq, "%d (unknown)\n", type);
550
551 seq_printf(seq, "HD 0 type : ");
552 type = nvram[4] >> 4;
553 if (type)
554 seq_printf(seq, "%02x\n", type == 0x0f ? nvram[11] : type);
555 else
556 seq_printf(seq, "none\n");
557
558 seq_printf(seq, "HD 1 type : ");
559 type = nvram[4] & 0x0f;
560 if (type)
561 seq_printf(seq, "%02x\n", type == 0x0f ? nvram[12] : type);
562 else
563 seq_printf(seq, "none\n");
564
565 seq_printf(seq, "HD type 48 data: %d/%d/%d C/H/S, precomp %d, lz %d\n",
566 nvram[18] | (nvram[19] << 8),
567 nvram[20], nvram[25],
568 nvram[21] | (nvram[22] << 8), nvram[23] | (nvram[24] << 8));
569 seq_printf(seq, "HD type 49 data: %d/%d/%d C/H/S, precomp %d, lz %d\n",
570 nvram[39] | (nvram[40] << 8),
571 nvram[41], nvram[46],
572 nvram[42] | (nvram[43] << 8), nvram[44] | (nvram[45] << 8));
573
574 seq_printf(seq, "DOS base memory: %d kB\n", nvram[7] | (nvram[8] << 8));
575 seq_printf(seq, "Extended memory: %d kB (configured), %d kB (tested)\n",
576 nvram[9] | (nvram[10] << 8), nvram[34] | (nvram[35] << 8));
577
578 seq_printf(seq, "Gfx adapter : %s\n",
579 gfx_types[(nvram[6] >> 4) & 3]);
580
581 seq_printf(seq, "FPU : %sinstalled\n",
582 (nvram[6] & 2) ? "" : "not ");
583
584 return;
585}
586#endif
587
588#endif /* MACH == PC */
589
590#if MACH == ATARI
591
592static int atari_check_checksum(void)
593{
594 int i;
595 unsigned char sum = 0;
596
597 for (i = ATARI_CKS_RANGE_START; i <= ATARI_CKS_RANGE_END; ++i)
598 sum += __nvram_read_byte(i);
599 return (__nvram_read_byte(ATARI_CKS_LOC) == (~sum & 0xff)) &&
600 (__nvram_read_byte(ATARI_CKS_LOC + 1) == (sum & 0xff));
601}
602
603static void atari_set_checksum(void)
604{
605 int i;
606 unsigned char sum = 0;
607
608 for (i = ATARI_CKS_RANGE_START; i <= ATARI_CKS_RANGE_END; ++i)
609 sum += __nvram_read_byte(i);
610 __nvram_write_byte(~sum, ATARI_CKS_LOC);
611 __nvram_write_byte(sum, ATARI_CKS_LOC + 1);
612}
613
614#ifdef CONFIG_PROC_FS
615
616static struct {
617 unsigned char val;
618 char *name;
619} boot_prefs[] = {
620 { 0x80, "TOS" },
621 { 0x40, "ASV" },
622 { 0x20, "NetBSD (?)" },
623 { 0x10, "Linux" },
624 { 0x00, "unspecified" }
625};
626
627static char *languages[] = {
628 "English (US)",
629 "German",
630 "French",
631 "English (UK)",
632 "Spanish",
633 "Italian",
634 "6 (undefined)",
635 "Swiss (French)",
636 "Swiss (German)"
637};
638
639static char *dateformat[] = {
640 "MM%cDD%cYY",
641 "DD%cMM%cYY",
642 "YY%cMM%cDD",
643 "YY%cDD%cMM",
644 "4 (undefined)",
645 "5 (undefined)",
646 "6 (undefined)",
647 "7 (undefined)"
648};
649
650static char *colors[] = {
651 "2", "4", "16", "256", "65536", "??", "??", "??"
652};
653
654static void atari_proc_infos(unsigned char *nvram, struct seq_file *seq,
655 void *offset)
656{
657 int checksum = nvram_check_checksum();
658 int i;
659 unsigned vmode;
660
661 seq_printf(seq, "Checksum status : %svalid\n", checksum ? "" : "not ");
662
663 seq_printf(seq, "Boot preference : ");
664 for (i = ARRAY_SIZE(boot_prefs) - 1; i >= 0; --i) {
665 if (nvram[1] == boot_prefs[i].val) {
666 seq_printf(seq, "%s\n", boot_prefs[i].name);
667 break;
668 }
669 }
670 if (i < 0)
671 seq_printf(seq, "0x%02x (undefined)\n", nvram[1]);
672
673 seq_printf(seq, "SCSI arbitration : %s\n",
674 (nvram[16] & 0x80) ? "on" : "off");
675 seq_printf(seq, "SCSI host ID : ");
676 if (nvram[16] & 0x80)
677 seq_printf(seq, "%d\n", nvram[16] & 7);
678 else
679 seq_printf(seq, "n/a\n");
680
681 /* the following entries are defined only for the Falcon */
682 if ((atari_mch_cookie >> 16) != ATARI_MCH_FALCON)
683 return;
684
685 seq_printf(seq, "OS language : ");
686 if (nvram[6] < ARRAY_SIZE(languages))
687 seq_printf(seq, "%s\n", languages[nvram[6]]);
688 else
689 seq_printf(seq, "%u (undefined)\n", nvram[6]);
690 seq_printf(seq, "Keyboard language: ");
691 if (nvram[7] < ARRAY_SIZE(languages))
692 seq_printf(seq, "%s\n", languages[nvram[7]]);
693 else
694 seq_printf(seq, "%u (undefined)\n", nvram[7]);
695 seq_printf(seq, "Date format : ");
696 seq_printf(seq, dateformat[nvram[8] & 7],
697 nvram[9] ? nvram[9] : '/', nvram[9] ? nvram[9] : '/');
698 seq_printf(seq, ", %dh clock\n", nvram[8] & 16 ? 24 : 12);
699 seq_printf(seq, "Boot delay : ");
700 if (nvram[10] == 0)
701 seq_printf(seq, "default");
702 else
703 seq_printf(seq, "%ds%s\n", nvram[10],
704 nvram[10] < 8 ? ", no memory test" : "");
705
706 vmode = (nvram[14] << 8) || nvram[15];
707 seq_printf(seq,
708 "Video mode : %s colors, %d columns, %s %s monitor\n",
709 colors[vmode & 7],
710 vmode & 8 ? 80 : 40,
711 vmode & 16 ? "VGA" : "TV", vmode & 32 ? "PAL" : "NTSC");
712 seq_printf(seq, " %soverscan, compat. mode %s%s\n",
713 vmode & 64 ? "" : "no ",
714 vmode & 128 ? "on" : "off",
715 vmode & 256 ?
716 (vmode & 16 ? ", line doubling" : ", half screen") : "");
717
718 return;
719}
720#endif
721
722#endif /* MACH == ATARI */
723
724MODULE_LICENSE("GPL");
725MODULE_ALIAS_MISCDEV(NVRAM_MINOR);
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
114
115static DEFINE_MUTEX(nvram_mutex);
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#if 0
200void 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
214static 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 default:
227 return -EINVAL;
228 }
229
230 return (offset >= 0) ? (file->f_pos = offset) : -EINVAL;
231}
232
233static ssize_t nvram_read(struct file *file, char __user *buf,
234 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
257checksum_err:
258 spin_unlock_irq(&rtc_lock);
259 return -EIO;
260}
261
262static ssize_t nvram_write(struct file *file, const char __user *buf,
263 size_t count, loff_t *ppos)
264{
265 unsigned char contents[NVRAM_BYTES];
266 unsigned i = *ppos;
267 unsigned char *tmp;
268
269 if (i >= NVRAM_BYTES)
270 return 0; /* Past EOF */
271
272 if (count > NVRAM_BYTES - i)
273 count = NVRAM_BYTES - i;
274 if (count > NVRAM_BYTES)
275 return -EFAULT; /* Can't happen, but prove it to gcc */
276
277 if (copy_from_user(contents, buf, count))
278 return -EFAULT;
279
280 spin_lock_irq(&rtc_lock);
281
282 if (!__nvram_check_checksum())
283 goto checksum_err;
284
285 for (tmp = contents; count--; ++i, ++tmp)
286 __nvram_write_byte(*tmp, i);
287
288 __nvram_set_checksum();
289
290 spin_unlock_irq(&rtc_lock);
291
292 *ppos = i;
293
294 return tmp - contents;
295
296checksum_err:
297 spin_unlock_irq(&rtc_lock);
298 return -EIO;
299}
300
301static long nvram_ioctl(struct file *file, unsigned int cmd,
302 unsigned long arg)
303{
304 int i;
305
306 switch (cmd) {
307
308 case NVRAM_INIT:
309 /* initialize NVRAM contents and checksum */
310 if (!capable(CAP_SYS_ADMIN))
311 return -EACCES;
312
313 mutex_lock(&nvram_mutex);
314 spin_lock_irq(&rtc_lock);
315
316 for (i = 0; i < NVRAM_BYTES; ++i)
317 __nvram_write_byte(0, i);
318 __nvram_set_checksum();
319
320 spin_unlock_irq(&rtc_lock);
321 mutex_unlock(&nvram_mutex);
322 return 0;
323
324 case NVRAM_SETCKS:
325 /* just set checksum, contents unchanged (maybe useful after
326 * checksum garbaged somehow...) */
327 if (!capable(CAP_SYS_ADMIN))
328 return -EACCES;
329
330 mutex_lock(&nvram_mutex);
331 spin_lock_irq(&rtc_lock);
332 __nvram_set_checksum();
333 spin_unlock_irq(&rtc_lock);
334 mutex_unlock(&nvram_mutex);
335 return 0;
336
337 default:
338 return -ENOTTY;
339 }
340}
341
342static int nvram_open(struct inode *inode, struct file *file)
343{
344 spin_lock(&nvram_state_lock);
345
346 if ((nvram_open_cnt && (file->f_flags & O_EXCL)) ||
347 (nvram_open_mode & NVRAM_EXCL) ||
348 ((file->f_mode & FMODE_WRITE) && (nvram_open_mode & NVRAM_WRITE))) {
349 spin_unlock(&nvram_state_lock);
350 return -EBUSY;
351 }
352
353 if (file->f_flags & O_EXCL)
354 nvram_open_mode |= NVRAM_EXCL;
355 if (file->f_mode & FMODE_WRITE)
356 nvram_open_mode |= NVRAM_WRITE;
357 nvram_open_cnt++;
358
359 spin_unlock(&nvram_state_lock);
360
361 return 0;
362}
363
364static int nvram_release(struct inode *inode, struct file *file)
365{
366 spin_lock(&nvram_state_lock);
367
368 nvram_open_cnt--;
369
370 /* if only one instance is open, clear the EXCL bit */
371 if (nvram_open_mode & NVRAM_EXCL)
372 nvram_open_mode &= ~NVRAM_EXCL;
373 if (file->f_mode & FMODE_WRITE)
374 nvram_open_mode &= ~NVRAM_WRITE;
375
376 spin_unlock(&nvram_state_lock);
377
378 return 0;
379}
380
381#ifndef CONFIG_PROC_FS
382static int nvram_add_proc_fs(void)
383{
384 return 0;
385}
386
387#else
388
389static int nvram_proc_read(struct seq_file *seq, void *offset)
390{
391 unsigned char contents[NVRAM_BYTES];
392 int i = 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 mach_proc_infos(contents, seq, offset);
400
401 return 0;
402}
403
404static int nvram_proc_open(struct inode *inode, struct file *file)
405{
406 return single_open(file, nvram_proc_read, NULL);
407}
408
409static const struct file_operations nvram_proc_fops = {
410 .owner = THIS_MODULE,
411 .open = nvram_proc_open,
412 .read = seq_read,
413 .llseek = seq_lseek,
414 .release = single_release,
415};
416
417static int nvram_add_proc_fs(void)
418{
419 if (!proc_create("driver/nvram", 0, NULL, &nvram_proc_fops))
420 return -ENOMEM;
421 return 0;
422}
423
424#endif /* CONFIG_PROC_FS */
425
426static const struct file_operations nvram_fops = {
427 .owner = THIS_MODULE,
428 .llseek = nvram_llseek,
429 .read = nvram_read,
430 .write = nvram_write,
431 .unlocked_ioctl = nvram_ioctl,
432 .open = nvram_open,
433 .release = nvram_release,
434};
435
436static struct miscdevice nvram_dev = {
437 NVRAM_MINOR,
438 "nvram",
439 &nvram_fops
440};
441
442static int __init nvram_init(void)
443{
444 int ret;
445
446 /* First test whether the driver should init at all */
447 if (!CHECK_DRIVER_INIT())
448 return -ENODEV;
449
450 ret = misc_register(&nvram_dev);
451 if (ret) {
452 printk(KERN_ERR "nvram: can't misc_register on minor=%d\n",
453 NVRAM_MINOR);
454 goto out;
455 }
456 ret = nvram_add_proc_fs();
457 if (ret) {
458 printk(KERN_ERR "nvram: can't create /proc/driver/nvram\n");
459 goto outmisc;
460 }
461 ret = 0;
462 printk(KERN_INFO "Non-volatile memory driver v" NVRAM_VERSION "\n");
463out:
464 return ret;
465outmisc:
466 misc_deregister(&nvram_dev);
467 goto out;
468}
469
470static void __exit nvram_cleanup_module(void)
471{
472 remove_proc_entry("driver/nvram", NULL);
473 misc_deregister(&nvram_dev);
474}
475
476module_init(nvram_init);
477module_exit(nvram_cleanup_module);
478
479/*
480 * Machine specific functions
481 */
482
483#if MACH == PC
484
485static int pc_check_checksum(void)
486{
487 int i;
488 unsigned short sum = 0;
489 unsigned short expect;
490
491 for (i = PC_CKS_RANGE_START; i <= PC_CKS_RANGE_END; ++i)
492 sum += __nvram_read_byte(i);
493 expect = __nvram_read_byte(PC_CKS_LOC)<<8 |
494 __nvram_read_byte(PC_CKS_LOC+1);
495 return (sum & 0xffff) == expect;
496}
497
498static void pc_set_checksum(void)
499{
500 int i;
501 unsigned short sum = 0;
502
503 for (i = PC_CKS_RANGE_START; i <= PC_CKS_RANGE_END; ++i)
504 sum += __nvram_read_byte(i);
505 __nvram_write_byte(sum >> 8, PC_CKS_LOC);
506 __nvram_write_byte(sum & 0xff, PC_CKS_LOC + 1);
507}
508
509#ifdef CONFIG_PROC_FS
510
511static char *floppy_types[] = {
512 "none", "5.25'' 360k", "5.25'' 1.2M", "3.5'' 720k", "3.5'' 1.44M",
513 "3.5'' 2.88M", "3.5'' 2.88M"
514};
515
516static char *gfx_types[] = {
517 "EGA, VGA, ... (with BIOS)",
518 "CGA (40 cols)",
519 "CGA (80 cols)",
520 "monochrome",
521};
522
523static void pc_proc_infos(unsigned char *nvram, struct seq_file *seq,
524 void *offset)
525{
526 int checksum;
527 int type;
528
529 spin_lock_irq(&rtc_lock);
530 checksum = __nvram_check_checksum();
531 spin_unlock_irq(&rtc_lock);
532
533 seq_printf(seq, "Checksum status: %svalid\n", checksum ? "" : "not ");
534
535 seq_printf(seq, "# floppies : %d\n",
536 (nvram[6] & 1) ? (nvram[6] >> 6) + 1 : 0);
537 seq_printf(seq, "Floppy 0 type : ");
538 type = nvram[2] >> 4;
539 if (type < ARRAY_SIZE(floppy_types))
540 seq_printf(seq, "%s\n", floppy_types[type]);
541 else
542 seq_printf(seq, "%d (unknown)\n", type);
543 seq_printf(seq, "Floppy 1 type : ");
544 type = nvram[2] & 0x0f;
545 if (type < ARRAY_SIZE(floppy_types))
546 seq_printf(seq, "%s\n", floppy_types[type]);
547 else
548 seq_printf(seq, "%d (unknown)\n", type);
549
550 seq_printf(seq, "HD 0 type : ");
551 type = nvram[4] >> 4;
552 if (type)
553 seq_printf(seq, "%02x\n", type == 0x0f ? nvram[11] : type);
554 else
555 seq_printf(seq, "none\n");
556
557 seq_printf(seq, "HD 1 type : ");
558 type = nvram[4] & 0x0f;
559 if (type)
560 seq_printf(seq, "%02x\n", type == 0x0f ? nvram[12] : type);
561 else
562 seq_printf(seq, "none\n");
563
564 seq_printf(seq, "HD type 48 data: %d/%d/%d C/H/S, precomp %d, lz %d\n",
565 nvram[18] | (nvram[19] << 8),
566 nvram[20], nvram[25],
567 nvram[21] | (nvram[22] << 8), nvram[23] | (nvram[24] << 8));
568 seq_printf(seq, "HD type 49 data: %d/%d/%d C/H/S, precomp %d, lz %d\n",
569 nvram[39] | (nvram[40] << 8),
570 nvram[41], nvram[46],
571 nvram[42] | (nvram[43] << 8), nvram[44] | (nvram[45] << 8));
572
573 seq_printf(seq, "DOS base memory: %d kB\n", nvram[7] | (nvram[8] << 8));
574 seq_printf(seq, "Extended memory: %d kB (configured), %d kB (tested)\n",
575 nvram[9] | (nvram[10] << 8), nvram[34] | (nvram[35] << 8));
576
577 seq_printf(seq, "Gfx adapter : %s\n",
578 gfx_types[(nvram[6] >> 4) & 3]);
579
580 seq_printf(seq, "FPU : %sinstalled\n",
581 (nvram[6] & 2) ? "" : "not ");
582
583 return;
584}
585#endif
586
587#endif /* MACH == PC */
588
589#if MACH == ATARI
590
591static int atari_check_checksum(void)
592{
593 int i;
594 unsigned char sum = 0;
595
596 for (i = ATARI_CKS_RANGE_START; i <= ATARI_CKS_RANGE_END; ++i)
597 sum += __nvram_read_byte(i);
598 return (__nvram_read_byte(ATARI_CKS_LOC) == (~sum & 0xff)) &&
599 (__nvram_read_byte(ATARI_CKS_LOC + 1) == (sum & 0xff));
600}
601
602static void atari_set_checksum(void)
603{
604 int i;
605 unsigned char sum = 0;
606
607 for (i = ATARI_CKS_RANGE_START; i <= ATARI_CKS_RANGE_END; ++i)
608 sum += __nvram_read_byte(i);
609 __nvram_write_byte(~sum, ATARI_CKS_LOC);
610 __nvram_write_byte(sum, ATARI_CKS_LOC + 1);
611}
612
613#ifdef CONFIG_PROC_FS
614
615static struct {
616 unsigned char val;
617 char *name;
618} boot_prefs[] = {
619 { 0x80, "TOS" },
620 { 0x40, "ASV" },
621 { 0x20, "NetBSD (?)" },
622 { 0x10, "Linux" },
623 { 0x00, "unspecified" }
624};
625
626static char *languages[] = {
627 "English (US)",
628 "German",
629 "French",
630 "English (UK)",
631 "Spanish",
632 "Italian",
633 "6 (undefined)",
634 "Swiss (French)",
635 "Swiss (German)"
636};
637
638static char *dateformat[] = {
639 "MM%cDD%cYY",
640 "DD%cMM%cYY",
641 "YY%cMM%cDD",
642 "YY%cDD%cMM",
643 "4 (undefined)",
644 "5 (undefined)",
645 "6 (undefined)",
646 "7 (undefined)"
647};
648
649static char *colors[] = {
650 "2", "4", "16", "256", "65536", "??", "??", "??"
651};
652
653static void atari_proc_infos(unsigned char *nvram, struct seq_file *seq,
654 void *offset)
655{
656 int checksum = nvram_check_checksum();
657 int i;
658 unsigned vmode;
659
660 seq_printf(seq, "Checksum status : %svalid\n", checksum ? "" : "not ");
661
662 seq_printf(seq, "Boot preference : ");
663 for (i = ARRAY_SIZE(boot_prefs) - 1; i >= 0; --i) {
664 if (nvram[1] == boot_prefs[i].val) {
665 seq_printf(seq, "%s\n", boot_prefs[i].name);
666 break;
667 }
668 }
669 if (i < 0)
670 seq_printf(seq, "0x%02x (undefined)\n", nvram[1]);
671
672 seq_printf(seq, "SCSI arbitration : %s\n",
673 (nvram[16] & 0x80) ? "on" : "off");
674 seq_printf(seq, "SCSI host ID : ");
675 if (nvram[16] & 0x80)
676 seq_printf(seq, "%d\n", nvram[16] & 7);
677 else
678 seq_printf(seq, "n/a\n");
679
680 /* the following entries are defined only for the Falcon */
681 if ((atari_mch_cookie >> 16) != ATARI_MCH_FALCON)
682 return;
683
684 seq_printf(seq, "OS language : ");
685 if (nvram[6] < ARRAY_SIZE(languages))
686 seq_printf(seq, "%s\n", languages[nvram[6]]);
687 else
688 seq_printf(seq, "%u (undefined)\n", nvram[6]);
689 seq_printf(seq, "Keyboard language: ");
690 if (nvram[7] < ARRAY_SIZE(languages))
691 seq_printf(seq, "%s\n", languages[nvram[7]]);
692 else
693 seq_printf(seq, "%u (undefined)\n", nvram[7]);
694 seq_printf(seq, "Date format : ");
695 seq_printf(seq, dateformat[nvram[8] & 7],
696 nvram[9] ? nvram[9] : '/', nvram[9] ? nvram[9] : '/');
697 seq_printf(seq, ", %dh clock\n", nvram[8] & 16 ? 24 : 12);
698 seq_printf(seq, "Boot delay : ");
699 if (nvram[10] == 0)
700 seq_printf(seq, "default");
701 else
702 seq_printf(seq, "%ds%s\n", nvram[10],
703 nvram[10] < 8 ? ", no memory test" : "");
704
705 vmode = (nvram[14] << 8) || nvram[15];
706 seq_printf(seq,
707 "Video mode : %s colors, %d columns, %s %s monitor\n",
708 colors[vmode & 7],
709 vmode & 8 ? 80 : 40,
710 vmode & 16 ? "VGA" : "TV", vmode & 32 ? "PAL" : "NTSC");
711 seq_printf(seq, " %soverscan, compat. mode %s%s\n",
712 vmode & 64 ? "" : "no ",
713 vmode & 128 ? "on" : "off",
714 vmode & 256 ?
715 (vmode & 16 ? ", line doubling" : ", half screen") : "");
716
717 return;
718}
719#endif
720
721#endif /* MACH == ATARI */
722
723MODULE_LICENSE("GPL");
724MODULE_ALIAS_MISCDEV(NVRAM_MINOR);