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
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>
46 /* select machine configuration */
47 #if defined(CONFIG_ATARI)
49 #elif defined(__i386__) || defined(__x86_64__) || defined(__arm__) /* and ?? */
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/seq_file.h>
110 #include <linux/spinlock.h>
111 #include <linux/io.h>
112 #include <linux/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 void mach_proc_infos(unsigned char *contents, struct seq_file *seq,
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.
141 unsigned char __nvram_read_byte(int i)
143 return CMOS_READ(NVRAM_FIRST_BYTE + i);
145 EXPORT_SYMBOL(__nvram_read_byte);
147 unsigned char nvram_read_byte(int i)
152 spin_lock_irqsave(&rtc_lock, flags);
153 c = __nvram_read_byte(i);
154 spin_unlock_irqrestore(&rtc_lock, flags);
157 EXPORT_SYMBOL(nvram_read_byte);
159 /* This races nicely with trying to read with checksum checking (nvram_read) */
160 void __nvram_write_byte(unsigned char c, int i)
162 CMOS_WRITE(c, NVRAM_FIRST_BYTE + i);
164 EXPORT_SYMBOL(__nvram_write_byte);
166 void nvram_write_byte(unsigned char c, int i)
170 spin_lock_irqsave(&rtc_lock, flags);
171 __nvram_write_byte(c, i);
172 spin_unlock_irqrestore(&rtc_lock, flags);
174 EXPORT_SYMBOL(nvram_write_byte);
176 int __nvram_check_checksum(void)
178 return mach_check_checksum();
180 EXPORT_SYMBOL(__nvram_check_checksum);
182 int nvram_check_checksum(void)
187 spin_lock_irqsave(&rtc_lock, flags);
188 rv = __nvram_check_checksum();
189 spin_unlock_irqrestore(&rtc_lock, flags);
192 EXPORT_SYMBOL(nvram_check_checksum);
194 static void __nvram_set_checksum(void)
200 void nvram_set_checksum(void)
204 spin_lock_irqsave(&rtc_lock, flags);
205 __nvram_set_checksum();
206 spin_unlock_irqrestore(&rtc_lock, flags);
211 * The are the file operation function for user access to /dev/nvram
214 static loff_t nvram_llseek(struct file *file, loff_t offset, int origin)
221 offset += file->f_pos;
224 offset += NVRAM_BYTES;
228 return (offset >= 0) ? (file->f_pos = offset) : -EINVAL;
231 static ssize_t nvram_read(struct file *file, char __user *buf,
232 size_t count, loff_t *ppos)
234 unsigned char contents[NVRAM_BYTES];
238 spin_lock_irq(&rtc_lock);
240 if (!__nvram_check_checksum())
243 for (tmp = contents; count-- > 0 && i < NVRAM_BYTES; ++i, ++tmp)
244 *tmp = __nvram_read_byte(i);
246 spin_unlock_irq(&rtc_lock);
248 if (copy_to_user(buf, contents, tmp - contents))
253 return tmp - contents;
256 spin_unlock_irq(&rtc_lock);
260 static ssize_t nvram_write(struct file *file, const char __user *buf,
261 size_t count, loff_t *ppos)
263 unsigned char contents[NVRAM_BYTES];
268 len = (NVRAM_BYTES - i) < count ? (NVRAM_BYTES - i) : count;
269 if (copy_from_user(contents, buf, len))
272 spin_lock_irq(&rtc_lock);
274 if (!__nvram_check_checksum())
277 for (tmp = contents; count-- > 0 && i < NVRAM_BYTES; ++i, ++tmp)
278 __nvram_write_byte(*tmp, i);
280 __nvram_set_checksum();
282 spin_unlock_irq(&rtc_lock);
286 return tmp - contents;
289 spin_unlock_irq(&rtc_lock);
293 static int nvram_ioctl(struct inode *inode, struct file *file,
294 unsigned int cmd, unsigned long arg)
301 /* initialize NVRAM contents and checksum */
302 if (!capable(CAP_SYS_ADMIN))
305 spin_lock_irq(&rtc_lock);
307 for (i = 0; i < NVRAM_BYTES; ++i)
308 __nvram_write_byte(0, i);
309 __nvram_set_checksum();
311 spin_unlock_irq(&rtc_lock);
315 /* just set checksum, contents unchanged (maybe useful after
316 * checksum garbaged somehow...) */
317 if (!capable(CAP_SYS_ADMIN))
320 spin_lock_irq(&rtc_lock);
321 __nvram_set_checksum();
322 spin_unlock_irq(&rtc_lock);
330 static int nvram_open(struct inode *inode, struct file *file)
333 spin_lock(&nvram_state_lock);
335 if ((nvram_open_cnt && (file->f_flags & O_EXCL)) ||
336 (nvram_open_mode & NVRAM_EXCL) ||
337 ((file->f_mode & FMODE_WRITE) && (nvram_open_mode & NVRAM_WRITE))) {
338 spin_unlock(&nvram_state_lock);
343 if (file->f_flags & O_EXCL)
344 nvram_open_mode |= NVRAM_EXCL;
345 if (file->f_mode & FMODE_WRITE)
346 nvram_open_mode |= NVRAM_WRITE;
349 spin_unlock(&nvram_state_lock);
355 static int nvram_release(struct inode *inode, struct file *file)
357 spin_lock(&nvram_state_lock);
361 /* if only one instance is open, clear the EXCL bit */
362 if (nvram_open_mode & NVRAM_EXCL)
363 nvram_open_mode &= ~NVRAM_EXCL;
364 if (file->f_mode & FMODE_WRITE)
365 nvram_open_mode &= ~NVRAM_WRITE;
367 spin_unlock(&nvram_state_lock);
372 #ifndef CONFIG_PROC_FS
373 static int nvram_add_proc_fs(void)
380 static int nvram_proc_read(struct seq_file *seq, void *offset)
382 unsigned char contents[NVRAM_BYTES];
385 spin_lock_irq(&rtc_lock);
386 for (i = 0; i < NVRAM_BYTES; ++i)
387 contents[i] = __nvram_read_byte(i);
388 spin_unlock_irq(&rtc_lock);
390 mach_proc_infos(contents, seq, offset);
395 static int nvram_proc_open(struct inode *inode, struct file *file)
397 return single_open(file, nvram_proc_read, NULL);
400 static const struct file_operations nvram_proc_fops = {
401 .owner = THIS_MODULE,
402 .open = nvram_proc_open,
405 .release = single_release,
408 static int nvram_add_proc_fs(void)
410 if (!proc_create("driver/nvram", 0, NULL, &nvram_proc_fops))
415 #endif /* CONFIG_PROC_FS */
417 static const struct file_operations nvram_fops = {
418 .owner = THIS_MODULE,
419 .llseek = nvram_llseek,
421 .write = nvram_write,
422 .ioctl = nvram_ioctl,
424 .release = nvram_release,
427 static struct miscdevice nvram_dev = {
433 static int __init nvram_init(void)
437 /* First test whether the driver should init at all */
438 if (!CHECK_DRIVER_INIT())
441 ret = misc_register(&nvram_dev);
443 printk(KERN_ERR "nvram: can't misc_register on minor=%d\n",
447 ret = nvram_add_proc_fs();
449 printk(KERN_ERR "nvram: can't create /proc/driver/nvram\n");
453 printk(KERN_INFO "Non-volatile memory driver v" NVRAM_VERSION "\n");
457 misc_deregister(&nvram_dev);
461 static void __exit nvram_cleanup_module(void)
463 remove_proc_entry("driver/nvram", NULL);
464 misc_deregister(&nvram_dev);
467 module_init(nvram_init);
468 module_exit(nvram_cleanup_module);
471 * Machine specific functions
476 static int pc_check_checksum(void)
479 unsigned short sum = 0;
480 unsigned short expect;
482 for (i = PC_CKS_RANGE_START; i <= PC_CKS_RANGE_END; ++i)
483 sum += __nvram_read_byte(i);
484 expect = __nvram_read_byte(PC_CKS_LOC)<<8 |
485 __nvram_read_byte(PC_CKS_LOC+1);
486 return (sum & 0xffff) == expect;
489 static void pc_set_checksum(void)
492 unsigned short sum = 0;
494 for (i = PC_CKS_RANGE_START; i <= PC_CKS_RANGE_END; ++i)
495 sum += __nvram_read_byte(i);
496 __nvram_write_byte(sum >> 8, PC_CKS_LOC);
497 __nvram_write_byte(sum & 0xff, PC_CKS_LOC + 1);
500 #ifdef CONFIG_PROC_FS
502 static char *floppy_types[] = {
503 "none", "5.25'' 360k", "5.25'' 1.2M", "3.5'' 720k", "3.5'' 1.44M",
504 "3.5'' 2.88M", "3.5'' 2.88M"
507 static char *gfx_types[] = {
508 "EGA, VGA, ... (with BIOS)",
514 static void pc_proc_infos(unsigned char *nvram, struct seq_file *seq,
520 spin_lock_irq(&rtc_lock);
521 checksum = __nvram_check_checksum();
522 spin_unlock_irq(&rtc_lock);
524 seq_printf(seq, "Checksum status: %svalid\n", checksum ? "" : "not ");
526 seq_printf(seq, "# floppies : %d\n",
527 (nvram[6] & 1) ? (nvram[6] >> 6) + 1 : 0);
528 seq_printf(seq, "Floppy 0 type : ");
529 type = nvram[2] >> 4;
530 if (type < ARRAY_SIZE(floppy_types))
531 seq_printf(seq, "%s\n", floppy_types[type]);
533 seq_printf(seq, "%d (unknown)\n", type);
534 seq_printf(seq, "Floppy 1 type : ");
535 type = nvram[2] & 0x0f;
536 if (type < ARRAY_SIZE(floppy_types))
537 seq_printf(seq, "%s\n", floppy_types[type]);
539 seq_printf(seq, "%d (unknown)\n", type);
541 seq_printf(seq, "HD 0 type : ");
542 type = nvram[4] >> 4;
544 seq_printf(seq, "%02x\n", type == 0x0f ? nvram[11] : type);
546 seq_printf(seq, "none\n");
548 seq_printf(seq, "HD 1 type : ");
549 type = nvram[4] & 0x0f;
551 seq_printf(seq, "%02x\n", type == 0x0f ? nvram[12] : type);
553 seq_printf(seq, "none\n");
555 seq_printf(seq, "HD type 48 data: %d/%d/%d C/H/S, precomp %d, lz %d\n",
556 nvram[18] | (nvram[19] << 8),
557 nvram[20], nvram[25],
558 nvram[21] | (nvram[22] << 8), nvram[23] | (nvram[24] << 8));
559 seq_printf(seq, "HD type 49 data: %d/%d/%d C/H/S, precomp %d, lz %d\n",
560 nvram[39] | (nvram[40] << 8),
561 nvram[41], nvram[46],
562 nvram[42] | (nvram[43] << 8), nvram[44] | (nvram[45] << 8));
564 seq_printf(seq, "DOS base memory: %d kB\n", nvram[7] | (nvram[8] << 8));
565 seq_printf(seq, "Extended memory: %d kB (configured), %d kB (tested)\n",
566 nvram[9] | (nvram[10] << 8), nvram[34] | (nvram[35] << 8));
568 seq_printf(seq, "Gfx adapter : %s\n",
569 gfx_types[(nvram[6] >> 4) & 3]);
571 seq_printf(seq, "FPU : %sinstalled\n",
572 (nvram[6] & 2) ? "" : "not ");
578 #endif /* MACH == PC */
582 static int atari_check_checksum(void)
585 unsigned char sum = 0;
587 for (i = ATARI_CKS_RANGE_START; i <= ATARI_CKS_RANGE_END; ++i)
588 sum += __nvram_read_byte(i);
589 return (__nvram_read_byte(ATARI_CKS_LOC) == (~sum & 0xff)) &&
590 (__nvram_read_byte(ATARI_CKS_LOC + 1) == (sum & 0xff));
593 static void atari_set_checksum(void)
596 unsigned char sum = 0;
598 for (i = ATARI_CKS_RANGE_START; i <= ATARI_CKS_RANGE_END; ++i)
599 sum += __nvram_read_byte(i);
600 __nvram_write_byte(~sum, ATARI_CKS_LOC);
601 __nvram_write_byte(sum, ATARI_CKS_LOC + 1);
604 #ifdef CONFIG_PROC_FS
612 { 0x20, "NetBSD (?)" },
614 { 0x00, "unspecified" }
617 static char *languages[] = {
629 static char *dateformat[] = {
640 static char *colors[] = {
641 "2", "4", "16", "256", "65536", "??", "??", "??"
644 static void atari_proc_infos(unsigned char *nvram, struct seq_file *seq,
647 int checksum = nvram_check_checksum();
651 seq_printf(seq, "Checksum status : %svalid\n", checksum ? "" : "not ");
653 seq_printf(seq, "Boot preference : ");
654 for (i = ARRAY_SIZE(boot_prefs) - 1; i >= 0; --i) {
655 if (nvram[1] == boot_prefs[i].val) {
656 seq_printf(seq, "%s\n", boot_prefs[i].name);
661 seq_printf(seq, "0x%02x (undefined)\n", nvram[1]);
663 seq_printf(seq, "SCSI arbitration : %s\n",
664 (nvram[16] & 0x80) ? "on" : "off");
665 seq_printf(seq, "SCSI host ID : ");
666 if (nvram[16] & 0x80)
667 seq_printf(seq, "%d\n", nvram[16] & 7);
669 seq_printf(seq, "n/a\n");
671 /* the following entries are defined only for the Falcon */
672 if ((atari_mch_cookie >> 16) != ATARI_MCH_FALCON)
675 seq_printf(seq, "OS language : ");
676 if (nvram[6] < ARRAY_SIZE(languages))
677 seq_printf(seq, "%s\n", languages[nvram[6]]);
679 seq_printf(seq, "%u (undefined)\n", nvram[6]);
680 seq_printf(seq, "Keyboard language: ");
681 if (nvram[7] < ARRAY_SIZE(languages))
682 seq_printf(seq, "%s\n", languages[nvram[7]]);
684 seq_printf(seq, "%u (undefined)\n", nvram[7]);
685 seq_printf(seq, "Date format : ");
686 seq_printf(seq, dateformat[nvram[8] & 7],
687 nvram[9] ? nvram[9] : '/', nvram[9] ? nvram[9] : '/');
688 seq_printf(seq, ", %dh clock\n", nvram[8] & 16 ? 24 : 12);
689 seq_printf(seq, "Boot delay : ");
691 seq_printf(seq, "default");
693 seq_printf(seq, "%ds%s\n", nvram[10],
694 nvram[10] < 8 ? ", no memory test" : "");
696 vmode = (nvram[14] << 8) || nvram[15];
698 "Video mode : %s colors, %d columns, %s %s monitor\n",
701 vmode & 16 ? "VGA" : "TV", vmode & 32 ? "PAL" : "NTSC");
702 seq_printf(seq, " %soverscan, compat. mode %s%s\n",
703 vmode & 64 ? "" : "no ",
704 vmode & 128 ? "on" : "off",
706 (vmode & 16 ? ", line doubling" : ", half screen") : "");
712 #endif /* MACH == ATARI */
714 MODULE_LICENSE("GPL");
715 MODULE_ALIAS_MISCDEV(NVRAM_MINOR);