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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#include <linux/pagemap.h>
114
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 return generic_file_llseek_size(file, offset, origin, MAX_LFS_FILESIZE,
218 NVRAM_BYTES);
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 mutex_lock(&nvram_mutex);
302 spin_lock_irq(&rtc_lock);
303
304 for (i = 0; i < NVRAM_BYTES; ++i)
305 __nvram_write_byte(0, i);
306 __nvram_set_checksum();
307
308 spin_unlock_irq(&rtc_lock);
309 mutex_unlock(&nvram_mutex);
310 return 0;
311
312 case NVRAM_SETCKS:
313 /* just set checksum, contents unchanged (maybe useful after
314 * checksum garbaged somehow...) */
315 if (!capable(CAP_SYS_ADMIN))
316 return -EACCES;
317
318 mutex_lock(&nvram_mutex);
319 spin_lock_irq(&rtc_lock);
320 __nvram_set_checksum();
321 spin_unlock_irq(&rtc_lock);
322 mutex_unlock(&nvram_mutex);
323 return 0;
324
325 default:
326 return -ENOTTY;
327 }
328}
329
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 const char * const 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 const char * const 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 const char *name;
606} boot_prefs[] = {
607 { 0x80, "TOS" },
608 { 0x40, "ASV" },
609 { 0x20, "NetBSD (?)" },
610 { 0x10, "Linux" },
611 { 0x00, "unspecified" }
612};
613
614static const char * const 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 const char * const 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 const char * const 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);