reset: zynq: add driver Kconfig option
[linux/fpc-iii.git] / drivers / char / nvram.c
blob678fa97e41fbe5583a52ad474de8eaab1ed8aaab
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/nvram.h>
43 #define PC 1
44 #define ATARI 2
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
55 #if MACH == PC
57 /* RTC in a PC */
58 #define CHECK_DRIVER_INIT() 1
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)
66 #define mach_check_checksum pc_check_checksum
67 #define mach_set_checksum pc_set_checksum
68 #define mach_proc_infos pc_proc_infos
70 #endif
72 #if MACH == ATARI
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))
80 #define NVRAM_BYTES 50
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
88 #define mach_check_checksum atari_check_checksum
89 #define mach_set_checksum atari_set_checksum
90 #define mach_proc_infos atari_proc_infos
92 #endif
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.)
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>
116 static DEFINE_MUTEX(nvram_mutex);
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 return generic_file_llseek_size(file, offset, origin, MAX_LFS_FILESIZE,
218 NVRAM_BYTES);
221 static ssize_t nvram_read(struct file *file, char __user *buf,
222 size_t count, loff_t *ppos)
224 unsigned char contents[NVRAM_BYTES];
225 unsigned i = *ppos;
226 unsigned char *tmp;
228 spin_lock_irq(&rtc_lock);
230 if (!__nvram_check_checksum())
231 goto checksum_err;
233 for (tmp = contents; count-- > 0 && i < NVRAM_BYTES; ++i, ++tmp)
234 *tmp = __nvram_read_byte(i);
236 spin_unlock_irq(&rtc_lock);
238 if (copy_to_user(buf, contents, tmp - contents))
239 return -EFAULT;
241 *ppos = i;
243 return tmp - contents;
245 checksum_err:
246 spin_unlock_irq(&rtc_lock);
247 return -EIO;
250 static ssize_t nvram_write(struct file *file, const char __user *buf,
251 size_t count, loff_t *ppos)
253 unsigned char contents[NVRAM_BYTES];
254 unsigned i = *ppos;
255 unsigned char *tmp;
257 if (i >= NVRAM_BYTES)
258 return 0; /* Past EOF */
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 */
265 if (copy_from_user(contents, buf, count))
266 return -EFAULT;
268 spin_lock_irq(&rtc_lock);
270 if (!__nvram_check_checksum())
271 goto checksum_err;
273 for (tmp = contents; count--; ++i, ++tmp)
274 __nvram_write_byte(*tmp, i);
276 __nvram_set_checksum();
278 spin_unlock_irq(&rtc_lock);
280 *ppos = i;
282 return tmp - contents;
284 checksum_err:
285 spin_unlock_irq(&rtc_lock);
286 return -EIO;
289 static long nvram_ioctl(struct file *file, unsigned int cmd,
290 unsigned long arg)
292 int i;
294 switch (cmd) {
296 case NVRAM_INIT:
297 /* initialize NVRAM contents and checksum */
298 if (!capable(CAP_SYS_ADMIN))
299 return -EACCES;
301 mutex_lock(&nvram_mutex);
302 spin_lock_irq(&rtc_lock);
304 for (i = 0; i < NVRAM_BYTES; ++i)
305 __nvram_write_byte(0, i);
306 __nvram_set_checksum();
308 spin_unlock_irq(&rtc_lock);
309 mutex_unlock(&nvram_mutex);
310 return 0;
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;
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;
325 default:
326 return -ENOTTY;
330 static int nvram_open(struct inode *inode, struct file *file)
332 spin_lock(&nvram_state_lock);
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;
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++;
347 spin_unlock(&nvram_state_lock);
349 return 0;
352 static int nvram_release(struct inode *inode, struct file *file)
354 spin_lock(&nvram_state_lock);
356 nvram_open_cnt--;
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;
364 spin_unlock(&nvram_state_lock);
366 return 0;
369 #ifndef CONFIG_PROC_FS
370 static int nvram_add_proc_fs(void)
372 return 0;
375 #else
377 static int nvram_proc_read(struct seq_file *seq, void *offset)
379 unsigned char contents[NVRAM_BYTES];
380 int i = 0;
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);
387 mach_proc_infos(contents, seq, offset);
389 return 0;
392 static int nvram_proc_open(struct inode *inode, struct file *file)
394 return single_open(file, nvram_proc_read, NULL);
397 static 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,
405 static int nvram_add_proc_fs(void)
407 if (!proc_create("driver/nvram", 0, NULL, &nvram_proc_fops))
408 return -ENOMEM;
409 return 0;
412 #endif /* CONFIG_PROC_FS */
414 static 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,
424 static struct miscdevice nvram_dev = {
425 NVRAM_MINOR,
426 "nvram",
427 &nvram_fops
430 static int __init nvram_init(void)
432 int ret;
434 /* First test whether the driver should init at all */
435 if (!CHECK_DRIVER_INIT())
436 return -ENODEV;
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;
444 ret = nvram_add_proc_fs();
445 if (ret) {
446 printk(KERN_ERR "nvram: can't create /proc/driver/nvram\n");
447 goto outmisc;
449 ret = 0;
450 printk(KERN_INFO "Non-volatile memory driver v" NVRAM_VERSION "\n");
451 out:
452 return ret;
453 outmisc:
454 misc_deregister(&nvram_dev);
455 goto out;
458 static void __exit nvram_cleanup_module(void)
460 remove_proc_entry("driver/nvram", NULL);
461 misc_deregister(&nvram_dev);
464 module_init(nvram_init);
465 module_exit(nvram_cleanup_module);
468 * Machine specific functions
471 #if MACH == PC
473 static int pc_check_checksum(void)
475 int i;
476 unsigned short sum = 0;
477 unsigned short expect;
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;
486 static void pc_set_checksum(void)
488 int i;
489 unsigned short sum = 0;
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);
497 #ifdef CONFIG_PROC_FS
499 static 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"
504 static const char * const gfx_types[] = {
505 "EGA, VGA, ... (with BIOS)",
506 "CGA (40 cols)",
507 "CGA (80 cols)",
508 "monochrome",
511 static void pc_proc_infos(unsigned char *nvram, struct seq_file *seq,
512 void *offset)
514 int checksum;
515 int type;
517 spin_lock_irq(&rtc_lock);
518 checksum = __nvram_check_checksum();
519 spin_unlock_irq(&rtc_lock);
521 seq_printf(seq, "Checksum status: %svalid\n", checksum ? "" : "not ");
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);
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");
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");
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));
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));
565 seq_printf(seq, "Gfx adapter : %s\n",
566 gfx_types[(nvram[6] >> 4) & 3]);
568 seq_printf(seq, "FPU : %sinstalled\n",
569 (nvram[6] & 2) ? "" : "not ");
571 return;
573 #endif
575 #endif /* MACH == PC */
577 #if MACH == ATARI
579 static int atari_check_checksum(void)
581 int i;
582 unsigned char sum = 0;
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));
590 static void atari_set_checksum(void)
592 int i;
593 unsigned char sum = 0;
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);
601 #ifdef CONFIG_PROC_FS
603 static 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" }
614 static 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)"
626 static 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)"
637 static const char * const colors[] = {
638 "2", "4", "16", "256", "65536", "??", "??", "??"
641 static void atari_proc_infos(unsigned char *nvram, struct seq_file *seq,
642 void *offset)
644 int checksum = nvram_check_checksum();
645 int i;
646 unsigned vmode;
648 seq_printf(seq, "Checksum status : %svalid\n", checksum ? "" : "not ");
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;
657 if (i < 0)
658 seq_printf(seq, "0x%02x (undefined)\n", nvram[1]);
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");
668 /* the following entries are defined only for the Falcon */
669 if ((atari_mch_cookie >> 16) != ATARI_MCH_FALCON)
670 return;
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" : "");
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") : "");
705 return;
707 #endif
709 #endif /* MACH == ATARI */
711 MODULE_LICENSE("GPL");
712 MODULE_ALIAS_MISCDEV(NVRAM_MINOR);