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
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
33 * 1.2 Erik Gilling: Cobalt Networks support
34 * Tim Hockin: general cleanup, Cobalt support
37 #define NVRAM_VERSION "1.2"
39 #include <linux/module.h>
40 #include <linux/smp_lock.h>
41 #include <linux/nvram.h>
46 /* select machine configuration */
47 #if defined(CONFIG_ATARI)
49 #elif defined(__i386__) || defined(__x86_64__) || defined(__arm__) /* and others?? */
52 # error Cannot build nvram driver for this machine configuration.
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
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
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
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.)
100 #include <linux/types.h>
101 #include <linux/errno.h>
102 #include <linux/miscdevice.h>
103 #include <linux/slab.h>
104 #include <linux/ioport.h>
105 #include <linux/fcntl.h>
106 #include <linux/mc146818rtc.h>
107 #include <linux/init.h>
108 #include <linux/proc_fs.h>
109 #include <linux/spinlock.h>
110 #include <linux/smp_lock.h>
113 #include <asm/uaccess.h>
114 #include <asm/system.h>
116 static DEFINE_SPINLOCK(nvram_state_lock);
117 static int nvram_open_cnt; /* #times opened */
118 static int nvram_open_mode; /* special open modes */
119 #define NVRAM_WRITE 1 /* opened for writing (exclusive) */
120 #define NVRAM_EXCL 2 /* opened with O_EXCL */
122 static int mach_check_checksum(void);
123 static void mach_set_checksum(void);
125 #ifdef CONFIG_PROC_FS
126 static int mach_proc_infos(unsigned char *contents, char *buffer, int *len,
127 off_t *begin, off_t offset, int size);
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).
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.
142 __nvram_read_byte(int i)
144 return CMOS_READ(NVRAM_FIRST_BYTE + i);
148 nvram_read_byte(int i)
153 spin_lock_irqsave(&rtc_lock, flags);
154 c = __nvram_read_byte(i);
155 spin_unlock_irqrestore(&rtc_lock, flags);
159 /* This races nicely with trying to read with checksum checking (nvram_read) */
161 __nvram_write_byte(unsigned char c, int i)
163 CMOS_WRITE(c, NVRAM_FIRST_BYTE + i);
167 nvram_write_byte(unsigned char c, int i)
171 spin_lock_irqsave(&rtc_lock, flags);
172 __nvram_write_byte(c, i);
173 spin_unlock_irqrestore(&rtc_lock, flags);
177 __nvram_check_checksum(void)
179 return mach_check_checksum();
183 nvram_check_checksum(void)
188 spin_lock_irqsave(&rtc_lock, flags);
189 rv = __nvram_check_checksum();
190 spin_unlock_irqrestore(&rtc_lock, flags);
195 __nvram_set_checksum(void)
202 nvram_set_checksum(void)
206 spin_lock_irqsave(&rtc_lock, flags);
207 __nvram_set_checksum();
208 spin_unlock_irqrestore(&rtc_lock, flags);
213 * The are the file operation function for user access to /dev/nvram
216 static loff_t nvram_llseek(struct file *file,loff_t offset, int origin )
224 offset += file->f_pos;
227 offset += NVRAM_BYTES;
231 return (offset >= 0) ? (file->f_pos = offset) : -EINVAL;
235 nvram_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
237 unsigned char contents[NVRAM_BYTES];
241 spin_lock_irq(&rtc_lock);
243 if (!__nvram_check_checksum())
246 for (tmp = contents; count-- > 0 && i < NVRAM_BYTES; ++i, ++tmp)
247 *tmp = __nvram_read_byte(i);
249 spin_unlock_irq(&rtc_lock);
251 if (copy_to_user(buf, contents, tmp - contents))
256 return tmp - contents;
259 spin_unlock_irq(&rtc_lock);
264 nvram_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos)
266 unsigned char contents[NVRAM_BYTES];
271 len = (NVRAM_BYTES - i) < count ? (NVRAM_BYTES - i) : count;
272 if (copy_from_user(contents, buf, len))
275 spin_lock_irq(&rtc_lock);
277 if (!__nvram_check_checksum())
280 for (tmp = contents; count-- > 0 && i < NVRAM_BYTES; ++i, ++tmp)
281 __nvram_write_byte(*tmp, i);
283 __nvram_set_checksum();
285 spin_unlock_irq(&rtc_lock);
289 return tmp - contents;
292 spin_unlock_irq(&rtc_lock);
297 nvram_ioctl(struct inode *inode, struct file *file,
298 unsigned int cmd, unsigned long arg)
305 /* initialize NVRAM contents and checksum */
306 if (!capable(CAP_SYS_ADMIN))
309 spin_lock_irq(&rtc_lock);
311 for (i = 0; i < NVRAM_BYTES; ++i)
312 __nvram_write_byte(0, i);
313 __nvram_set_checksum();
315 spin_unlock_irq(&rtc_lock);
319 /* just set checksum, contents unchanged (maybe useful after
320 * checksum garbaged somehow...) */
321 if (!capable(CAP_SYS_ADMIN))
324 spin_lock_irq(&rtc_lock);
325 __nvram_set_checksum();
326 spin_unlock_irq(&rtc_lock);
335 nvram_open(struct inode *inode, struct file *file)
338 spin_lock(&nvram_state_lock);
340 if ((nvram_open_cnt && (file->f_flags & O_EXCL)) ||
341 (nvram_open_mode & NVRAM_EXCL) ||
342 ((file->f_mode & 2) && (nvram_open_mode & NVRAM_WRITE))) {
343 spin_unlock(&nvram_state_lock);
348 if (file->f_flags & O_EXCL)
349 nvram_open_mode |= NVRAM_EXCL;
350 if (file->f_mode & 2)
351 nvram_open_mode |= NVRAM_WRITE;
354 spin_unlock(&nvram_state_lock);
361 nvram_release(struct inode *inode, struct file *file)
363 spin_lock(&nvram_state_lock);
367 /* if only one instance is open, clear the EXCL bit */
368 if (nvram_open_mode & NVRAM_EXCL)
369 nvram_open_mode &= ~NVRAM_EXCL;
370 if (file->f_mode & 2)
371 nvram_open_mode &= ~NVRAM_WRITE;
373 spin_unlock(&nvram_state_lock);
378 #ifndef CONFIG_PROC_FS
380 nvram_read_proc(char *buffer, char **start, off_t offset,
381 int size, int *eof, void *data)
388 nvram_read_proc(char *buffer, char **start, off_t offset,
389 int size, int *eof, void *data)
391 unsigned char contents[NVRAM_BYTES];
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);
400 *eof = mach_proc_infos(contents, buffer, &len, &begin, offset, size);
402 if (offset >= begin + len)
404 *start = buffer + (offset - begin);
405 return (size < begin + len - offset) ? size : begin + len - offset;
409 /* This macro frees the machine specific function from bounds checking and
410 * this like that... */
411 #define PRINT_PROC(fmt,args...) \
413 *len += sprintf(buffer+*len, fmt, ##args); \
414 if (*begin + *len > offset + size) \
416 if (*begin + *len < offset) { \
422 #endif /* CONFIG_PROC_FS */
424 static const struct file_operations nvram_fops = {
425 .owner = THIS_MODULE,
426 .llseek = nvram_llseek,
428 .write = nvram_write,
429 .ioctl = nvram_ioctl,
431 .release = nvram_release,
434 static struct miscdevice nvram_dev = {
445 /* First test whether the driver should init at all */
446 if (!CHECK_DRIVER_INIT())
449 ret = misc_register(&nvram_dev);
451 printk(KERN_ERR "nvram: can't misc_register on minor=%d\n",
455 if (!create_proc_read_entry("driver/nvram", 0, NULL, nvram_read_proc,
457 printk(KERN_ERR "nvram: can't create /proc/driver/nvram\n");
462 printk(KERN_INFO "Non-volatile memory driver v" NVRAM_VERSION "\n");
466 misc_deregister(&nvram_dev);
471 nvram_cleanup_module(void)
473 remove_proc_entry("driver/nvram", NULL);
474 misc_deregister(&nvram_dev);
477 module_init(nvram_init);
478 module_exit(nvram_cleanup_module);
481 * Machine specific functions
487 pc_check_checksum(void)
490 unsigned short sum = 0;
491 unsigned short expect;
493 for (i = PC_CKS_RANGE_START; i <= PC_CKS_RANGE_END; ++i)
494 sum += __nvram_read_byte(i);
495 expect = __nvram_read_byte(PC_CKS_LOC)<<8 |
496 __nvram_read_byte(PC_CKS_LOC+1);
497 return ((sum & 0xffff) == expect);
501 pc_set_checksum(void)
504 unsigned short sum = 0;
506 for (i = PC_CKS_RANGE_START; i <= PC_CKS_RANGE_END; ++i)
507 sum += __nvram_read_byte(i);
508 __nvram_write_byte(sum >> 8, PC_CKS_LOC);
509 __nvram_write_byte(sum & 0xff, PC_CKS_LOC + 1);
512 #ifdef CONFIG_PROC_FS
514 static char *floppy_types[] = {
515 "none", "5.25'' 360k", "5.25'' 1.2M", "3.5'' 720k", "3.5'' 1.44M",
516 "3.5'' 2.88M", "3.5'' 2.88M"
519 static char *gfx_types[] = {
520 "EGA, VGA, ... (with BIOS)",
527 pc_proc_infos(unsigned char *nvram, char *buffer, int *len,
528 off_t *begin, off_t offset, int size)
533 spin_lock_irq(&rtc_lock);
534 checksum = __nvram_check_checksum();
535 spin_unlock_irq(&rtc_lock);
537 PRINT_PROC("Checksum status: %svalid\n", checksum ? "" : "not ");
539 PRINT_PROC("# floppies : %d\n",
540 (nvram[6] & 1) ? (nvram[6] >> 6) + 1 : 0);
541 PRINT_PROC("Floppy 0 type : ");
542 type = nvram[2] >> 4;
543 if (type < ARRAY_SIZE(floppy_types))
544 PRINT_PROC("%s\n", floppy_types[type]);
546 PRINT_PROC("%d (unknown)\n", type);
547 PRINT_PROC("Floppy 1 type : ");
548 type = nvram[2] & 0x0f;
549 if (type < ARRAY_SIZE(floppy_types))
550 PRINT_PROC("%s\n", floppy_types[type]);
552 PRINT_PROC("%d (unknown)\n", type);
554 PRINT_PROC("HD 0 type : ");
555 type = nvram[4] >> 4;
557 PRINT_PROC("%02x\n", type == 0x0f ? nvram[11] : type);
559 PRINT_PROC("none\n");
561 PRINT_PROC("HD 1 type : ");
562 type = nvram[4] & 0x0f;
564 PRINT_PROC("%02x\n", type == 0x0f ? nvram[12] : type);
566 PRINT_PROC("none\n");
568 PRINT_PROC("HD type 48 data: %d/%d/%d C/H/S, precomp %d, lz %d\n",
569 nvram[18] | (nvram[19] << 8),
570 nvram[20], nvram[25],
571 nvram[21] | (nvram[22] << 8), nvram[23] | (nvram[24] << 8));
572 PRINT_PROC("HD type 49 data: %d/%d/%d C/H/S, precomp %d, lz %d\n",
573 nvram[39] | (nvram[40] << 8),
574 nvram[41], nvram[46],
575 nvram[42] | (nvram[43] << 8), nvram[44] | (nvram[45] << 8));
577 PRINT_PROC("DOS base memory: %d kB\n", nvram[7] | (nvram[8] << 8));
578 PRINT_PROC("Extended memory: %d kB (configured), %d kB (tested)\n",
579 nvram[9] | (nvram[10] << 8), nvram[34] | (nvram[35] << 8));
581 PRINT_PROC("Gfx adapter : %s\n", gfx_types[(nvram[6] >> 4) & 3]);
583 PRINT_PROC("FPU : %sinstalled\n",
584 (nvram[6] & 2) ? "" : "not ");
590 #endif /* MACH == PC */
595 atari_check_checksum(void)
598 unsigned char sum = 0;
600 for (i = ATARI_CKS_RANGE_START; i <= ATARI_CKS_RANGE_END; ++i)
601 sum += __nvram_read_byte(i);
602 return (__nvram_read_byte(ATARI_CKS_LOC) == (~sum & 0xff) &&
603 __nvram_read_byte(ATARI_CKS_LOC + 1) == (sum & 0xff));
607 atari_set_checksum(void)
610 unsigned char sum = 0;
612 for (i = ATARI_CKS_RANGE_START; i <= ATARI_CKS_RANGE_END; ++i)
613 sum += __nvram_read_byte(i);
614 __nvram_write_byte(~sum, ATARI_CKS_LOC);
615 __nvram_write_byte(sum, ATARI_CKS_LOC + 1);
618 #ifdef CONFIG_PROC_FS
626 { 0x20, "NetBSD (?)" },
628 { 0x00, "unspecified" }
631 static char *languages[] = {
643 static char *dateformat[] = {
654 static char *colors[] = {
655 "2", "4", "16", "256", "65536", "??", "??", "??"
659 atari_proc_infos(unsigned char *nvram, char *buffer, int *len,
660 off_t *begin, off_t offset, int size)
662 int checksum = nvram_check_checksum();
666 PRINT_PROC("Checksum status : %svalid\n", checksum ? "" : "not ");
668 PRINT_PROC("Boot preference : ");
669 for (i = ARRAY_SIZE(boot_prefs) - 1; i >= 0; --i) {
670 if (nvram[1] == boot_prefs[i].val) {
671 PRINT_PROC("%s\n", boot_prefs[i].name);
676 PRINT_PROC("0x%02x (undefined)\n", nvram[1]);
678 PRINT_PROC("SCSI arbitration : %s\n",
679 (nvram[16] & 0x80) ? "on" : "off");
680 PRINT_PROC("SCSI host ID : ");
681 if (nvram[16] & 0x80)
682 PRINT_PROC("%d\n", nvram[16] & 7);
686 /* the following entries are defined only for the Falcon */
687 if ((atari_mch_cookie >> 16) != ATARI_MCH_FALCON)
690 PRINT_PROC("OS language : ");
691 if (nvram[6] < ARRAY_SIZE(languages))
692 PRINT_PROC("%s\n", languages[nvram[6]]);
694 PRINT_PROC("%u (undefined)\n", nvram[6]);
695 PRINT_PROC("Keyboard language: ");
696 if (nvram[7] < ARRAY_SIZE(languages))
697 PRINT_PROC("%s\n", languages[nvram[7]]);
699 PRINT_PROC("%u (undefined)\n", nvram[7]);
700 PRINT_PROC("Date format : ");
701 PRINT_PROC(dateformat[nvram[8] & 7],
702 nvram[9] ? nvram[9] : '/', nvram[9] ? nvram[9] : '/');
703 PRINT_PROC(", %dh clock\n", nvram[8] & 16 ? 24 : 12);
704 PRINT_PROC("Boot delay : ");
706 PRINT_PROC("default");
708 PRINT_PROC("%ds%s\n", nvram[10],
709 nvram[10] < 8 ? ", no memory test" : "");
711 vmode = (nvram[14] << 8) || nvram[15];
712 PRINT_PROC("Video mode : %s colors, %d columns, %s %s monitor\n",
715 vmode & 16 ? "VGA" : "TV", vmode & 32 ? "PAL" : "NTSC");
716 PRINT_PROC(" %soverscan, compat. mode %s%s\n",
717 vmode & 64 ? "" : "no ",
718 vmode & 128 ? "on" : "off",
720 (vmode & 16 ? ", line doubling" : ", half screen") : "");
726 #endif /* MACH == ATARI */
728 MODULE_LICENSE("GPL");
730 EXPORT_SYMBOL(__nvram_read_byte);
731 EXPORT_SYMBOL(nvram_read_byte);
732 EXPORT_SYMBOL(__nvram_write_byte);
733 EXPORT_SYMBOL(nvram_write_byte);
734 EXPORT_SYMBOL(__nvram_check_checksum);
735 EXPORT_SYMBOL(nvram_check_checksum);
736 MODULE_ALIAS_MISCDEV(NVRAM_MINOR);