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 ?? */
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/io.h>
111 #include <linux/uaccess.h>
113 #include <asm/system.h>
115 static DEFINE_SPINLOCK(nvram_state_lock
);
116 static int nvram_open_cnt
; /* #times opened */
117 static int nvram_open_mode
; /* special open modes */
118 #define NVRAM_WRITE 1 /* opened for writing (exclusive) */
119 #define NVRAM_EXCL 2 /* opened with O_EXCL */
121 static int mach_check_checksum(void);
122 static void mach_set_checksum(void);
124 #ifdef CONFIG_PROC_FS
125 static int mach_proc_infos(unsigned char *contents
, char *buffer
, int *len
,
126 off_t
*begin
, off_t offset
, int size
);
130 * These functions are provided to be called internally or by other parts of
131 * the kernel. It's up to the caller to ensure correct checksum before reading
132 * or after writing (needs to be done only once).
134 * It is worth noting that these functions all access bytes of general
135 * purpose memory in the NVRAM - that is to say, they all add the
136 * NVRAM_FIRST_BYTE offset. Pass them offsets into NVRAM as if you did not
137 * know about the RTC cruft.
140 unsigned char __nvram_read_byte(int i
)
142 return CMOS_READ(NVRAM_FIRST_BYTE
+ i
);
144 EXPORT_SYMBOL(__nvram_read_byte
);
146 unsigned char nvram_read_byte(int i
)
151 spin_lock_irqsave(&rtc_lock
, flags
);
152 c
= __nvram_read_byte(i
);
153 spin_unlock_irqrestore(&rtc_lock
, flags
);
156 EXPORT_SYMBOL(nvram_read_byte
);
158 /* This races nicely with trying to read with checksum checking (nvram_read) */
159 void __nvram_write_byte(unsigned char c
, int i
)
161 CMOS_WRITE(c
, NVRAM_FIRST_BYTE
+ i
);
163 EXPORT_SYMBOL(__nvram_write_byte
);
165 void nvram_write_byte(unsigned char c
, int i
)
169 spin_lock_irqsave(&rtc_lock
, flags
);
170 __nvram_write_byte(c
, i
);
171 spin_unlock_irqrestore(&rtc_lock
, flags
);
173 EXPORT_SYMBOL(nvram_write_byte
);
175 int __nvram_check_checksum(void)
177 return mach_check_checksum();
179 EXPORT_SYMBOL(__nvram_check_checksum
);
181 int nvram_check_checksum(void)
186 spin_lock_irqsave(&rtc_lock
, flags
);
187 rv
= __nvram_check_checksum();
188 spin_unlock_irqrestore(&rtc_lock
, flags
);
191 EXPORT_SYMBOL(nvram_check_checksum
);
193 static void __nvram_set_checksum(void)
199 void nvram_set_checksum(void)
203 spin_lock_irqsave(&rtc_lock
, flags
);
204 __nvram_set_checksum();
205 spin_unlock_irqrestore(&rtc_lock
, flags
);
210 * The are the file operation function for user access to /dev/nvram
213 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_read_proc(char *buffer
, char **start
, off_t offset
,
374 int size
, int *eof
, void *data
)
380 static int nvram_read_proc(char *buffer
, char **start
, off_t offset
,
381 int size
, int *eof
, void *data
)
383 unsigned char contents
[NVRAM_BYTES
];
387 spin_lock_irq(&rtc_lock
);
388 for (i
= 0; i
< NVRAM_BYTES
; ++i
)
389 contents
[i
] = __nvram_read_byte(i
);
390 spin_unlock_irq(&rtc_lock
);
392 *eof
= mach_proc_infos(contents
, buffer
, &len
, &begin
, offset
, size
);
394 if (offset
>= begin
+ len
)
396 *start
= buffer
+ (offset
- begin
);
397 return (size
< begin
+ len
- offset
) ? size
: begin
+ len
- offset
;
401 /* This macro frees the machine specific function from bounds checking and
402 * this like that... */
403 #define PRINT_PROC(fmt,args...) \
405 *len += sprintf(buffer + *len, fmt, ##args); \
406 if (*begin + *len > offset + size) \
408 if (*begin + *len < offset) { \
414 #endif /* CONFIG_PROC_FS */
416 static const struct file_operations nvram_fops
= {
417 .owner
= THIS_MODULE
,
418 .llseek
= nvram_llseek
,
420 .write
= nvram_write
,
421 .ioctl
= nvram_ioctl
,
423 .release
= nvram_release
,
426 static struct miscdevice nvram_dev
= {
432 static int __init
nvram_init(void)
436 /* First test whether the driver should init at all */
437 if (!CHECK_DRIVER_INIT())
440 ret
= misc_register(&nvram_dev
);
442 printk(KERN_ERR
"nvram: can't misc_register on minor=%d\n",
446 if (!create_proc_read_entry("driver/nvram", 0, NULL
, nvram_read_proc
,
448 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 int pc_proc_infos(unsigned char *nvram
, char *buffer
, int *len
,
515 off_t
*begin
, off_t offset
, int size
)
520 spin_lock_irq(&rtc_lock
);
521 checksum
= __nvram_check_checksum();
522 spin_unlock_irq(&rtc_lock
);
524 PRINT_PROC("Checksum status: %svalid\n", checksum
? "" : "not ");
526 PRINT_PROC("# floppies : %d\n",
527 (nvram
[6] & 1) ? (nvram
[6] >> 6) + 1 : 0);
528 PRINT_PROC("Floppy 0 type : ");
529 type
= nvram
[2] >> 4;
530 if (type
< ARRAY_SIZE(floppy_types
))
531 PRINT_PROC("%s\n", floppy_types
[type
]);
533 PRINT_PROC("%d (unknown)\n", type
);
534 PRINT_PROC("Floppy 1 type : ");
535 type
= nvram
[2] & 0x0f;
536 if (type
< ARRAY_SIZE(floppy_types
))
537 PRINT_PROC("%s\n", floppy_types
[type
]);
539 PRINT_PROC("%d (unknown)\n", type
);
541 PRINT_PROC("HD 0 type : ");
542 type
= nvram
[4] >> 4;
544 PRINT_PROC("%02x\n", type
== 0x0f ? nvram
[11] : type
);
546 PRINT_PROC("none\n");
548 PRINT_PROC("HD 1 type : ");
549 type
= nvram
[4] & 0x0f;
551 PRINT_PROC("%02x\n", type
== 0x0f ? nvram
[12] : type
);
553 PRINT_PROC("none\n");
555 PRINT_PROC("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 PRINT_PROC("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 PRINT_PROC("DOS base memory: %d kB\n", nvram
[7] | (nvram
[8] << 8));
565 PRINT_PROC("Extended memory: %d kB (configured), %d kB (tested)\n",
566 nvram
[9] | (nvram
[10] << 8), nvram
[34] | (nvram
[35] << 8));
568 PRINT_PROC("Gfx adapter : %s\n", gfx_types
[(nvram
[6] >> 4) & 3]);
570 PRINT_PROC("FPU : %sinstalled\n",
571 (nvram
[6] & 2) ? "" : "not ");
577 #endif /* MACH == PC */
581 static int atari_check_checksum(void)
584 unsigned char sum
= 0;
586 for (i
= ATARI_CKS_RANGE_START
; i
<= ATARI_CKS_RANGE_END
; ++i
)
587 sum
+= __nvram_read_byte(i
);
588 return (__nvram_read_byte(ATARI_CKS_LOC
) == (~sum
& 0xff)) &&
589 (__nvram_read_byte(ATARI_CKS_LOC
+ 1) == (sum
& 0xff));
592 static void atari_set_checksum(void)
595 unsigned char sum
= 0;
597 for (i
= ATARI_CKS_RANGE_START
; i
<= ATARI_CKS_RANGE_END
; ++i
)
598 sum
+= __nvram_read_byte(i
);
599 __nvram_write_byte(~sum
, ATARI_CKS_LOC
);
600 __nvram_write_byte(sum
, ATARI_CKS_LOC
+ 1);
603 #ifdef CONFIG_PROC_FS
611 { 0x20, "NetBSD (?)" },
613 { 0x00, "unspecified" }
616 static char *languages
[] = {
628 static char *dateformat
[] = {
639 static char *colors
[] = {
640 "2", "4", "16", "256", "65536", "??", "??", "??"
643 static int atari_proc_infos(unsigned char *nvram
, char *buffer
, int *len
,
644 off_t
*begin
, off_t offset
, int size
)
646 int checksum
= nvram_check_checksum();
650 PRINT_PROC("Checksum status : %svalid\n", checksum
? "" : "not ");
652 PRINT_PROC("Boot preference : ");
653 for (i
= ARRAY_SIZE(boot_prefs
) - 1; i
>= 0; --i
) {
654 if (nvram
[1] == boot_prefs
[i
].val
) {
655 PRINT_PROC("%s\n", boot_prefs
[i
].name
);
660 PRINT_PROC("0x%02x (undefined)\n", nvram
[1]);
662 PRINT_PROC("SCSI arbitration : %s\n",
663 (nvram
[16] & 0x80) ? "on" : "off");
664 PRINT_PROC("SCSI host ID : ");
665 if (nvram
[16] & 0x80)
666 PRINT_PROC("%d\n", nvram
[16] & 7);
670 /* the following entries are defined only for the Falcon */
671 if ((atari_mch_cookie
>> 16) != ATARI_MCH_FALCON
)
674 PRINT_PROC("OS language : ");
675 if (nvram
[6] < ARRAY_SIZE(languages
))
676 PRINT_PROC("%s\n", languages
[nvram
[6]]);
678 PRINT_PROC("%u (undefined)\n", nvram
[6]);
679 PRINT_PROC("Keyboard language: ");
680 if (nvram
[7] < ARRAY_SIZE(languages
))
681 PRINT_PROC("%s\n", languages
[nvram
[7]]);
683 PRINT_PROC("%u (undefined)\n", nvram
[7]);
684 PRINT_PROC("Date format : ");
685 PRINT_PROC(dateformat
[nvram
[8] & 7],
686 nvram
[9] ? nvram
[9] : '/', nvram
[9] ? nvram
[9] : '/');
687 PRINT_PROC(", %dh clock\n", nvram
[8] & 16 ? 24 : 12);
688 PRINT_PROC("Boot delay : ");
690 PRINT_PROC("default");
692 PRINT_PROC("%ds%s\n", nvram
[10],
693 nvram
[10] < 8 ? ", no memory test" : "");
695 vmode
= (nvram
[14] << 8) || nvram
[15];
696 PRINT_PROC("Video mode : %s colors, %d columns, %s %s monitor\n",
699 vmode
& 16 ? "VGA" : "TV", vmode
& 32 ? "PAL" : "NTSC");
700 PRINT_PROC(" %soverscan, compat. mode %s%s\n",
701 vmode
& 64 ? "" : "no ",
702 vmode
& 128 ? "on" : "off",
704 (vmode
& 16 ? ", line doubling" : ", half screen") : "");
710 #endif /* MACH == ATARI */
712 MODULE_LICENSE("GPL");
713 MODULE_ALIAS_MISCDEV(NVRAM_MINOR
);