xref: /linux/drivers/char/nvram.c (revision 14b42963f64b98ab61fa9723c03d71aa5ef4f862)
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  */
36 
37 #define NVRAM_VERSION	"1.2"
38 
39 #include <linux/module.h>
40 #include <linux/sched.h>
41 #include <linux/smp_lock.h>
42 #include <linux/nvram.h>
43 
44 #define PC		1
45 #define ATARI		2
46 #define COBALT		3
47 
48 /* select machine configuration */
49 #if defined(CONFIG_ATARI)
50 #  define MACH ATARI
51 #elif defined(__i386__) || defined(__x86_64__) || defined(__arm__)  /* and others?? */
52 #define MACH PC
53 #  if defined(CONFIG_COBALT)
54 #    include <linux/cobalt-nvram.h>
55 #    define MACH COBALT
56 #  else
57 #    define MACH PC
58 #  endif
59 #else
60 #  error Cannot build nvram driver for this machine configuration.
61 #endif
62 
63 #if MACH == PC
64 
65 /* RTC in a PC */
66 #define CHECK_DRIVER_INIT()	1
67 
68 /* On PCs, the checksum is built only over bytes 2..31 */
69 #define PC_CKS_RANGE_START	2
70 #define PC_CKS_RANGE_END	31
71 #define PC_CKS_LOC		32
72 #define NVRAM_BYTES		(128-NVRAM_FIRST_BYTE)
73 
74 #define mach_check_checksum	pc_check_checksum
75 #define mach_set_checksum	pc_set_checksum
76 #define mach_proc_infos		pc_proc_infos
77 
78 #endif
79 
80 #if MACH == COBALT
81 
82 #define CHECK_DRIVER_INIT()     1
83 
84 #define NVRAM_BYTES		(128-NVRAM_FIRST_BYTE)
85 
86 #define mach_check_checksum	cobalt_check_checksum
87 #define mach_set_checksum	cobalt_set_checksum
88 #define mach_proc_infos		cobalt_proc_infos
89 
90 #endif
91 
92 #if MACH == ATARI
93 
94 /* Special parameters for RTC in Atari machines */
95 #include <asm/atarihw.h>
96 #include <asm/atariints.h>
97 #define RTC_PORT(x)		(TT_RTC_BAS + 2*(x))
98 #define CHECK_DRIVER_INIT()	(MACH_IS_ATARI && ATARIHW_PRESENT(TT_CLK))
99 
100 #define NVRAM_BYTES		50
101 
102 /* On Ataris, the checksum is over all bytes except the checksum bytes
103  * themselves; these are at the very end */
104 #define ATARI_CKS_RANGE_START	0
105 #define ATARI_CKS_RANGE_END	47
106 #define ATARI_CKS_LOC		48
107 
108 #define mach_check_checksum	atari_check_checksum
109 #define mach_set_checksum	atari_set_checksum
110 #define mach_proc_infos		atari_proc_infos
111 
112 #endif
113 
114 /* Note that *all* calls to CMOS_READ and CMOS_WRITE must be done with
115  * rtc_lock held. Due to the index-port/data-port design of the RTC, we
116  * don't want two different things trying to get to it at once. (e.g. the
117  * periodic 11 min sync from time.c vs. this driver.)
118  */
119 
120 #include <linux/types.h>
121 #include <linux/errno.h>
122 #include <linux/miscdevice.h>
123 #include <linux/slab.h>
124 #include <linux/ioport.h>
125 #include <linux/fcntl.h>
126 #include <linux/mc146818rtc.h>
127 #include <linux/init.h>
128 #include <linux/proc_fs.h>
129 #include <linux/spinlock.h>
130 
131 #include <asm/io.h>
132 #include <asm/uaccess.h>
133 #include <asm/system.h>
134 
135 static DEFINE_SPINLOCK(nvram_state_lock);
136 static int nvram_open_cnt;	/* #times opened */
137 static int nvram_open_mode;	/* special open modes */
138 #define NVRAM_WRITE		1 /* opened for writing (exclusive) */
139 #define NVRAM_EXCL		2 /* opened with O_EXCL */
140 
141 static int mach_check_checksum(void);
142 static void mach_set_checksum(void);
143 
144 #ifdef CONFIG_PROC_FS
145 static int mach_proc_infos(unsigned char *contents, char *buffer, int *len,
146     off_t *begin, off_t offset, int size);
147 #endif
148 
149 /*
150  * These functions are provided to be called internally or by other parts of
151  * the kernel. It's up to the caller to ensure correct checksum before reading
152  * or after writing (needs to be done only once).
153  *
154  * It is worth noting that these functions all access bytes of general
155  * purpose memory in the NVRAM - that is to say, they all add the
156  * NVRAM_FIRST_BYTE offset.  Pass them offsets into NVRAM as if you did not
157  * know about the RTC cruft.
158  */
159 
160 unsigned char
161 __nvram_read_byte(int i)
162 {
163 	return CMOS_READ(NVRAM_FIRST_BYTE + i);
164 }
165 
166 unsigned char
167 nvram_read_byte(int i)
168 {
169 	unsigned long flags;
170 	unsigned char c;
171 
172 	spin_lock_irqsave(&rtc_lock, flags);
173 	c = __nvram_read_byte(i);
174 	spin_unlock_irqrestore(&rtc_lock, flags);
175 	return c;
176 }
177 
178 /* This races nicely with trying to read with checksum checking (nvram_read) */
179 void
180 __nvram_write_byte(unsigned char c, int i)
181 {
182 	CMOS_WRITE(c, NVRAM_FIRST_BYTE + i);
183 }
184 
185 void
186 nvram_write_byte(unsigned char c, int i)
187 {
188 	unsigned long flags;
189 
190 	spin_lock_irqsave(&rtc_lock, flags);
191 	__nvram_write_byte(c, i);
192 	spin_unlock_irqrestore(&rtc_lock, flags);
193 }
194 
195 int
196 __nvram_check_checksum(void)
197 {
198 	return mach_check_checksum();
199 }
200 
201 int
202 nvram_check_checksum(void)
203 {
204 	unsigned long flags;
205 	int rv;
206 
207 	spin_lock_irqsave(&rtc_lock, flags);
208 	rv = __nvram_check_checksum();
209 	spin_unlock_irqrestore(&rtc_lock, flags);
210 	return rv;
211 }
212 
213 static void
214 __nvram_set_checksum(void)
215 {
216 	mach_set_checksum();
217 }
218 
219 #if 0
220 void
221 nvram_set_checksum(void)
222 {
223 	unsigned long flags;
224 
225 	spin_lock_irqsave(&rtc_lock, flags);
226 	__nvram_set_checksum();
227 	spin_unlock_irqrestore(&rtc_lock, flags);
228 }
229 #endif  /*  0  */
230 
231 /*
232  * The are the file operation function for user access to /dev/nvram
233  */
234 
235 static loff_t nvram_llseek(struct file *file,loff_t offset, int origin )
236 {
237 	lock_kernel();
238 	switch (origin) {
239 	case 0:
240 		/* nothing to do */
241 		break;
242 	case 1:
243 		offset += file->f_pos;
244 		break;
245 	case 2:
246 		offset += NVRAM_BYTES;
247 		break;
248 	}
249 	unlock_kernel();
250 	return (offset >= 0) ? (file->f_pos = offset) : -EINVAL;
251 }
252 
253 static ssize_t
254 nvram_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
255 {
256 	unsigned char contents[NVRAM_BYTES];
257 	unsigned i = *ppos;
258 	unsigned char *tmp;
259 
260 	spin_lock_irq(&rtc_lock);
261 
262 	if (!__nvram_check_checksum())
263 		goto checksum_err;
264 
265 	for (tmp = contents; count-- > 0 && i < NVRAM_BYTES; ++i, ++tmp)
266 		*tmp = __nvram_read_byte(i);
267 
268 	spin_unlock_irq(&rtc_lock);
269 
270 	if (copy_to_user(buf, contents, tmp - contents))
271 		return -EFAULT;
272 
273 	*ppos = i;
274 
275 	return tmp - contents;
276 
277       checksum_err:
278 	spin_unlock_irq(&rtc_lock);
279 	return -EIO;
280 }
281 
282 static ssize_t
283 nvram_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos)
284 {
285 	unsigned char contents[NVRAM_BYTES];
286 	unsigned i = *ppos;
287 	unsigned char *tmp;
288 	int len;
289 
290 	len = (NVRAM_BYTES - i) < count ? (NVRAM_BYTES - i) : count;
291 	if (copy_from_user(contents, buf, len))
292 		return -EFAULT;
293 
294 	spin_lock_irq(&rtc_lock);
295 
296 	if (!__nvram_check_checksum())
297 		goto checksum_err;
298 
299 	for (tmp = contents; count-- > 0 && i < NVRAM_BYTES; ++i, ++tmp)
300 		__nvram_write_byte(*tmp, i);
301 
302 	__nvram_set_checksum();
303 
304 	spin_unlock_irq(&rtc_lock);
305 
306 	*ppos = i;
307 
308 	return tmp - contents;
309 
310       checksum_err:
311 	spin_unlock_irq(&rtc_lock);
312 	return -EIO;
313 }
314 
315 static int
316 nvram_ioctl(struct inode *inode, struct file *file,
317     unsigned int cmd, unsigned long arg)
318 {
319 	int i;
320 
321 	switch (cmd) {
322 
323 	case NVRAM_INIT:
324 		/* initialize NVRAM contents and checksum */
325 		if (!capable(CAP_SYS_ADMIN))
326 			return -EACCES;
327 
328 		spin_lock_irq(&rtc_lock);
329 
330 		for (i = 0; i < NVRAM_BYTES; ++i)
331 			__nvram_write_byte(0, i);
332 		__nvram_set_checksum();
333 
334 		spin_unlock_irq(&rtc_lock);
335 		return 0;
336 
337 	case NVRAM_SETCKS:
338 		/* just set checksum, contents unchanged (maybe useful after
339 		 * checksum garbaged somehow...) */
340 		if (!capable(CAP_SYS_ADMIN))
341 			return -EACCES;
342 
343 		spin_lock_irq(&rtc_lock);
344 		__nvram_set_checksum();
345 		spin_unlock_irq(&rtc_lock);
346 		return 0;
347 
348 	default:
349 		return -ENOTTY;
350 	}
351 }
352 
353 static int
354 nvram_open(struct inode *inode, struct file *file)
355 {
356 	spin_lock(&nvram_state_lock);
357 
358 	if ((nvram_open_cnt && (file->f_flags & O_EXCL)) ||
359 	    (nvram_open_mode & NVRAM_EXCL) ||
360 	    ((file->f_mode & 2) && (nvram_open_mode & NVRAM_WRITE))) {
361 		spin_unlock(&nvram_state_lock);
362 		return -EBUSY;
363 	}
364 
365 	if (file->f_flags & O_EXCL)
366 		nvram_open_mode |= NVRAM_EXCL;
367 	if (file->f_mode & 2)
368 		nvram_open_mode |= NVRAM_WRITE;
369 	nvram_open_cnt++;
370 
371 	spin_unlock(&nvram_state_lock);
372 
373 	return 0;
374 }
375 
376 static int
377 nvram_release(struct inode *inode, struct file *file)
378 {
379 	spin_lock(&nvram_state_lock);
380 
381 	nvram_open_cnt--;
382 
383 	/* if only one instance is open, clear the EXCL bit */
384 	if (nvram_open_mode & NVRAM_EXCL)
385 		nvram_open_mode &= ~NVRAM_EXCL;
386 	if (file->f_mode & 2)
387 		nvram_open_mode &= ~NVRAM_WRITE;
388 
389 	spin_unlock(&nvram_state_lock);
390 
391 	return 0;
392 }
393 
394 #ifndef CONFIG_PROC_FS
395 static int
396 nvram_read_proc(char *buffer, char **start, off_t offset,
397     int size, int *eof, void *data)
398 {
399 	return 0;
400 }
401 #else
402 
403 static int
404 nvram_read_proc(char *buffer, char **start, off_t offset,
405     int size, int *eof, void *data)
406 {
407 	unsigned char contents[NVRAM_BYTES];
408 	int i, len = 0;
409 	off_t begin = 0;
410 
411 	spin_lock_irq(&rtc_lock);
412 	for (i = 0; i < NVRAM_BYTES; ++i)
413 		contents[i] = __nvram_read_byte(i);
414 	spin_unlock_irq(&rtc_lock);
415 
416 	*eof = mach_proc_infos(contents, buffer, &len, &begin, offset, size);
417 
418 	if (offset >= begin + len)
419 		return 0;
420 	*start = buffer + (offset - begin);
421 	return (size < begin + len - offset) ? size : begin + len - offset;
422 
423 }
424 
425 /* This macro frees the machine specific function from bounds checking and
426  * this like that... */
427 #define PRINT_PROC(fmt,args...)					\
428 	do {							\
429 		*len += sprintf(buffer+*len, fmt, ##args);	\
430 		if (*begin + *len > offset + size)		\
431 			return 0;				\
432 		if (*begin + *len < offset) {			\
433 			*begin += *len;				\
434 			*len = 0;				\
435 		}						\
436 	} while(0)
437 
438 #endif /* CONFIG_PROC_FS */
439 
440 static const struct file_operations nvram_fops = {
441 	.owner		= THIS_MODULE,
442 	.llseek		= nvram_llseek,
443 	.read		= nvram_read,
444 	.write		= nvram_write,
445 	.ioctl		= nvram_ioctl,
446 	.open		= nvram_open,
447 	.release	= nvram_release,
448 };
449 
450 static struct miscdevice nvram_dev = {
451 	NVRAM_MINOR,
452 	"nvram",
453 	&nvram_fops
454 };
455 
456 static int __init
457 nvram_init(void)
458 {
459 	int ret;
460 
461 	/* First test whether the driver should init at all */
462 	if (!CHECK_DRIVER_INIT())
463 		return -ENXIO;
464 
465 	ret = misc_register(&nvram_dev);
466 	if (ret) {
467 		printk(KERN_ERR "nvram: can't misc_register on minor=%d\n",
468 		    NVRAM_MINOR);
469 		goto out;
470 	}
471 	if (!create_proc_read_entry("driver/nvram", 0, NULL, nvram_read_proc,
472 		NULL)) {
473 		printk(KERN_ERR "nvram: can't create /proc/driver/nvram\n");
474 		ret = -ENOMEM;
475 		goto outmisc;
476 	}
477 	ret = 0;
478 	printk(KERN_INFO "Non-volatile memory driver v" NVRAM_VERSION "\n");
479       out:
480 	return ret;
481       outmisc:
482 	misc_deregister(&nvram_dev);
483 	goto out;
484 }
485 
486 static void __exit
487 nvram_cleanup_module(void)
488 {
489 	remove_proc_entry("driver/nvram", NULL);
490 	misc_deregister(&nvram_dev);
491 }
492 
493 module_init(nvram_init);
494 module_exit(nvram_cleanup_module);
495 
496 /*
497  * Machine specific functions
498  */
499 
500 #if MACH == PC
501 
502 static int
503 pc_check_checksum(void)
504 {
505 	int i;
506 	unsigned short sum = 0;
507 	unsigned short expect;
508 
509 	for (i = PC_CKS_RANGE_START; i <= PC_CKS_RANGE_END; ++i)
510 		sum += __nvram_read_byte(i);
511 	expect = __nvram_read_byte(PC_CKS_LOC)<<8 |
512 	    __nvram_read_byte(PC_CKS_LOC+1);
513 	return ((sum & 0xffff) == expect);
514 }
515 
516 static void
517 pc_set_checksum(void)
518 {
519 	int i;
520 	unsigned short sum = 0;
521 
522 	for (i = PC_CKS_RANGE_START; i <= PC_CKS_RANGE_END; ++i)
523 		sum += __nvram_read_byte(i);
524 	__nvram_write_byte(sum >> 8, PC_CKS_LOC);
525 	__nvram_write_byte(sum & 0xff, PC_CKS_LOC + 1);
526 }
527 
528 #ifdef CONFIG_PROC_FS
529 
530 static char *floppy_types[] = {
531 	"none", "5.25'' 360k", "5.25'' 1.2M", "3.5'' 720k", "3.5'' 1.44M",
532 	"3.5'' 2.88M", "3.5'' 2.88M"
533 };
534 
535 static char *gfx_types[] = {
536 	"EGA, VGA, ... (with BIOS)",
537 	"CGA (40 cols)",
538 	"CGA (80 cols)",
539 	"monochrome",
540 };
541 
542 static int
543 pc_proc_infos(unsigned char *nvram, char *buffer, int *len,
544     off_t *begin, off_t offset, int size)
545 {
546 	int checksum;
547 	int type;
548 
549 	spin_lock_irq(&rtc_lock);
550 	checksum = __nvram_check_checksum();
551 	spin_unlock_irq(&rtc_lock);
552 
553 	PRINT_PROC("Checksum status: %svalid\n", checksum ? "" : "not ");
554 
555 	PRINT_PROC("# floppies     : %d\n",
556 	    (nvram[6] & 1) ? (nvram[6] >> 6) + 1 : 0);
557 	PRINT_PROC("Floppy 0 type  : ");
558 	type = nvram[2] >> 4;
559 	if (type < ARRAY_SIZE(floppy_types))
560 		PRINT_PROC("%s\n", floppy_types[type]);
561 	else
562 		PRINT_PROC("%d (unknown)\n", type);
563 	PRINT_PROC("Floppy 1 type  : ");
564 	type = nvram[2] & 0x0f;
565 	if (type < ARRAY_SIZE(floppy_types))
566 		PRINT_PROC("%s\n", floppy_types[type]);
567 	else
568 		PRINT_PROC("%d (unknown)\n", type);
569 
570 	PRINT_PROC("HD 0 type      : ");
571 	type = nvram[4] >> 4;
572 	if (type)
573 		PRINT_PROC("%02x\n", type == 0x0f ? nvram[11] : type);
574 	else
575 		PRINT_PROC("none\n");
576 
577 	PRINT_PROC("HD 1 type      : ");
578 	type = nvram[4] & 0x0f;
579 	if (type)
580 		PRINT_PROC("%02x\n", type == 0x0f ? nvram[12] : type);
581 	else
582 		PRINT_PROC("none\n");
583 
584 	PRINT_PROC("HD type 48 data: %d/%d/%d C/H/S, precomp %d, lz %d\n",
585 	    nvram[18] | (nvram[19] << 8),
586 	    nvram[20], nvram[25],
587 	    nvram[21] | (nvram[22] << 8), nvram[23] | (nvram[24] << 8));
588 	PRINT_PROC("HD type 49 data: %d/%d/%d C/H/S, precomp %d, lz %d\n",
589 	    nvram[39] | (nvram[40] << 8),
590 	    nvram[41], nvram[46],
591 	    nvram[42] | (nvram[43] << 8), nvram[44] | (nvram[45] << 8));
592 
593 	PRINT_PROC("DOS base memory: %d kB\n", nvram[7] | (nvram[8] << 8));
594 	PRINT_PROC("Extended memory: %d kB (configured), %d kB (tested)\n",
595 	    nvram[9] | (nvram[10] << 8), nvram[34] | (nvram[35] << 8));
596 
597 	PRINT_PROC("Gfx adapter    : %s\n", gfx_types[(nvram[6] >> 4) & 3]);
598 
599 	PRINT_PROC("FPU            : %sinstalled\n",
600 	    (nvram[6] & 2) ? "" : "not ");
601 
602 	return 1;
603 }
604 #endif
605 
606 #endif /* MACH == PC */
607 
608 #if MACH == COBALT
609 
610 /* the cobalt CMOS has a wider range of its checksum */
611 static int cobalt_check_checksum(void)
612 {
613 	int i;
614 	unsigned short sum = 0;
615 	unsigned short expect;
616 
617 	for (i = COBT_CMOS_CKS_START; i <= COBT_CMOS_CKS_END; ++i) {
618 		if ((i == COBT_CMOS_CHECKSUM) || (i == (COBT_CMOS_CHECKSUM+1)))
619 			continue;
620 
621 		sum += __nvram_read_byte(i);
622 	}
623 	expect = __nvram_read_byte(COBT_CMOS_CHECKSUM) << 8 |
624 	    __nvram_read_byte(COBT_CMOS_CHECKSUM+1);
625 	return ((sum & 0xffff) == expect);
626 }
627 
628 static void cobalt_set_checksum(void)
629 {
630 	int i;
631 	unsigned short sum = 0;
632 
633 	for (i = COBT_CMOS_CKS_START; i <= COBT_CMOS_CKS_END; ++i) {
634 		if ((i == COBT_CMOS_CHECKSUM) || (i == (COBT_CMOS_CHECKSUM+1)))
635 			continue;
636 
637 		sum += __nvram_read_byte(i);
638 	}
639 
640 	__nvram_write_byte(sum >> 8, COBT_CMOS_CHECKSUM);
641 	__nvram_write_byte(sum & 0xff, COBT_CMOS_CHECKSUM+1);
642 }
643 
644 #ifdef CONFIG_PROC_FS
645 
646 static int cobalt_proc_infos(unsigned char *nvram, char *buffer, int *len,
647 	off_t *begin, off_t offset, int size)
648 {
649 	int i;
650 	unsigned int checksum;
651 	unsigned int flags;
652 	char sernum[14];
653 	char *key = "cNoEbTaWlOtR!";
654 	unsigned char bto_csum;
655 
656 	spin_lock_irq(&rtc_lock);
657 	checksum = __nvram_check_checksum();
658 	spin_unlock_irq(&rtc_lock);
659 
660 	PRINT_PROC("Checksum status: %svalid\n", checksum ? "" : "not ");
661 
662 	flags = nvram[COBT_CMOS_FLAG_BYTE_0] << 8
663 	    | nvram[COBT_CMOS_FLAG_BYTE_1];
664 
665 	PRINT_PROC("Console: %s\n",
666 		flags & COBT_CMOS_CONSOLE_FLAG ?  "on": "off");
667 
668 	PRINT_PROC("Firmware Debug Messages: %s\n",
669 		flags & COBT_CMOS_DEBUG_FLAG ? "on": "off");
670 
671 	PRINT_PROC("Auto Prompt: %s\n",
672 		flags & COBT_CMOS_AUTO_PROMPT_FLAG ? "on": "off");
673 
674 	PRINT_PROC("Shutdown Status: %s\n",
675 		flags & COBT_CMOS_CLEAN_BOOT_FLAG ? "clean": "dirty");
676 
677 	PRINT_PROC("Hardware Probe: %s\n",
678 		flags & COBT_CMOS_HW_NOPROBE_FLAG ? "partial": "full");
679 
680 	PRINT_PROC("System Fault: %sdetected\n",
681 		flags & COBT_CMOS_SYSFAULT_FLAG ? "": "not ");
682 
683 	PRINT_PROC("Panic on OOPS: %s\n",
684 		flags & COBT_CMOS_OOPSPANIC_FLAG ? "yes": "no");
685 
686 	PRINT_PROC("Delayed Cache Initialization: %s\n",
687 		flags & COBT_CMOS_DELAY_CACHE_FLAG ? "yes": "no");
688 
689 	PRINT_PROC("Show Logo at Boot: %s\n",
690 		flags & COBT_CMOS_NOLOGO_FLAG ? "no": "yes");
691 
692 	PRINT_PROC("Boot Method: ");
693 	switch (nvram[COBT_CMOS_BOOT_METHOD]) {
694 	case COBT_CMOS_BOOT_METHOD_DISK:
695 		PRINT_PROC("disk\n");
696 		break;
697 
698 	case COBT_CMOS_BOOT_METHOD_ROM:
699 		PRINT_PROC("rom\n");
700 		break;
701 
702 	case COBT_CMOS_BOOT_METHOD_NET:
703 		PRINT_PROC("net\n");
704 		break;
705 
706 	default:
707 		PRINT_PROC("unknown\n");
708 		break;
709 	}
710 
711 	PRINT_PROC("Primary Boot Device: %d:%d\n",
712 		nvram[COBT_CMOS_BOOT_DEV0_MAJ],
713 		nvram[COBT_CMOS_BOOT_DEV0_MIN] );
714 	PRINT_PROC("Secondary Boot Device: %d:%d\n",
715 		nvram[COBT_CMOS_BOOT_DEV1_MAJ],
716 		nvram[COBT_CMOS_BOOT_DEV1_MIN] );
717 	PRINT_PROC("Tertiary Boot Device: %d:%d\n",
718 		nvram[COBT_CMOS_BOOT_DEV2_MAJ],
719 		nvram[COBT_CMOS_BOOT_DEV2_MIN] );
720 
721 	PRINT_PROC("Uptime: %d\n",
722 		nvram[COBT_CMOS_UPTIME_0] << 24 |
723 		nvram[COBT_CMOS_UPTIME_1] << 16 |
724 		nvram[COBT_CMOS_UPTIME_2] << 8  |
725 		nvram[COBT_CMOS_UPTIME_3]);
726 
727 	PRINT_PROC("Boot Count: %d\n",
728 		nvram[COBT_CMOS_BOOTCOUNT_0] << 24 |
729 		nvram[COBT_CMOS_BOOTCOUNT_1] << 16 |
730 		nvram[COBT_CMOS_BOOTCOUNT_2] << 8  |
731 		nvram[COBT_CMOS_BOOTCOUNT_3]);
732 
733 	/* 13 bytes of serial num */
734 	for (i=0 ; i<13 ; i++) {
735 		sernum[i] = nvram[COBT_CMOS_SYS_SERNUM_0 + i];
736 	}
737 	sernum[13] = '\0';
738 
739 	checksum = 0;
740 	for (i=0 ; i<13 ; i++) {
741 		checksum += sernum[i] ^ key[i];
742 	}
743 	checksum = ((checksum & 0x7f) ^ (0xd6)) & 0xff;
744 
745 	PRINT_PROC("Serial Number: %s", sernum);
746 	if (checksum != nvram[COBT_CMOS_SYS_SERNUM_CSUM]) {
747 		PRINT_PROC(" (invalid checksum)");
748 	}
749 	PRINT_PROC("\n");
750 
751 	PRINT_PROC("Rom Revison: %d.%d.%d\n", nvram[COBT_CMOS_ROM_REV_MAJ],
752 		nvram[COBT_CMOS_ROM_REV_MIN], nvram[COBT_CMOS_ROM_REV_REV]);
753 
754 	PRINT_PROC("BTO Server: %d.%d.%d.%d", nvram[COBT_CMOS_BTO_IP_0],
755 		nvram[COBT_CMOS_BTO_IP_1], nvram[COBT_CMOS_BTO_IP_2],
756 		nvram[COBT_CMOS_BTO_IP_3]);
757 	bto_csum = nvram[COBT_CMOS_BTO_IP_0] + nvram[COBT_CMOS_BTO_IP_1]
758 		+ nvram[COBT_CMOS_BTO_IP_2] + nvram[COBT_CMOS_BTO_IP_3];
759 	if (bto_csum != nvram[COBT_CMOS_BTO_IP_CSUM]) {
760 		PRINT_PROC(" (invalid checksum)");
761 	}
762 	PRINT_PROC("\n");
763 
764 	if (flags & COBT_CMOS_VERSION_FLAG
765 	 && nvram[COBT_CMOS_VERSION] >= COBT_CMOS_VER_BTOCODE) {
766 		PRINT_PROC("BTO Code: 0x%x\n",
767 			nvram[COBT_CMOS_BTO_CODE_0] << 24 |
768 			nvram[COBT_CMOS_BTO_CODE_1] << 16 |
769 			nvram[COBT_CMOS_BTO_CODE_2] << 8 |
770 			nvram[COBT_CMOS_BTO_CODE_3]);
771 	}
772 
773 	return 1;
774 }
775 #endif /* CONFIG_PROC_FS */
776 
777 #endif /* MACH == COBALT */
778 
779 #if MACH == ATARI
780 
781 static int
782 atari_check_checksum(void)
783 {
784 	int i;
785 	unsigned char sum = 0;
786 
787 	for (i = ATARI_CKS_RANGE_START; i <= ATARI_CKS_RANGE_END; ++i)
788 		sum += __nvram_read_byte(i);
789 	return (__nvram_read_byte(ATARI_CKS_LOC) == (~sum & 0xff) &&
790 	    __nvram_read_byte(ATARI_CKS_LOC + 1) == (sum & 0xff));
791 }
792 
793 static void
794 atari_set_checksum(void)
795 {
796 	int i;
797 	unsigned char sum = 0;
798 
799 	for (i = ATARI_CKS_RANGE_START; i <= ATARI_CKS_RANGE_END; ++i)
800 		sum += __nvram_read_byte(i);
801 	__nvram_write_byte(~sum, ATARI_CKS_LOC);
802 	__nvram_write_byte(sum, ATARI_CKS_LOC + 1);
803 }
804 
805 #ifdef CONFIG_PROC_FS
806 
807 static struct {
808 	unsigned char val;
809 	char *name;
810 } boot_prefs[] = {
811 	{ 0x80, "TOS" },
812 	{ 0x40, "ASV" },
813 	{ 0x20, "NetBSD (?)" },
814 	{ 0x10, "Linux" },
815 	{ 0x00, "unspecified" }
816 };
817 
818 static char *languages[] = {
819 	"English (US)",
820 	"German",
821 	"French",
822 	"English (UK)",
823 	"Spanish",
824 	"Italian",
825 	"6 (undefined)",
826 	"Swiss (French)",
827 	"Swiss (German)"
828 };
829 
830 static char *dateformat[] = {
831 	"MM%cDD%cYY",
832 	"DD%cMM%cYY",
833 	"YY%cMM%cDD",
834 	"YY%cDD%cMM",
835 	"4 (undefined)",
836 	"5 (undefined)",
837 	"6 (undefined)",
838 	"7 (undefined)"
839 };
840 
841 static char *colors[] = {
842 	"2", "4", "16", "256", "65536", "??", "??", "??"
843 };
844 
845 static int
846 atari_proc_infos(unsigned char *nvram, char *buffer, int *len,
847     off_t *begin, off_t offset, int size)
848 {
849 	int checksum = nvram_check_checksum();
850 	int i;
851 	unsigned vmode;
852 
853 	PRINT_PROC("Checksum status  : %svalid\n", checksum ? "" : "not ");
854 
855 	PRINT_PROC("Boot preference  : ");
856 	for (i = ARRAY_SIZE(boot_prefs) - 1; i >= 0; --i) {
857 		if (nvram[1] == boot_prefs[i].val) {
858 			PRINT_PROC("%s\n", boot_prefs[i].name);
859 			break;
860 		}
861 	}
862 	if (i < 0)
863 		PRINT_PROC("0x%02x (undefined)\n", nvram[1]);
864 
865 	PRINT_PROC("SCSI arbitration : %s\n",
866 	    (nvram[16] & 0x80) ? "on" : "off");
867 	PRINT_PROC("SCSI host ID     : ");
868 	if (nvram[16] & 0x80)
869 		PRINT_PROC("%d\n", nvram[16] & 7);
870 	else
871 		PRINT_PROC("n/a\n");
872 
873 	/* the following entries are defined only for the Falcon */
874 	if ((atari_mch_cookie >> 16) != ATARI_MCH_FALCON)
875 		return 1;
876 
877 	PRINT_PROC("OS language      : ");
878 	if (nvram[6] < ARRAY_SIZE(languages))
879 		PRINT_PROC("%s\n", languages[nvram[6]]);
880 	else
881 		PRINT_PROC("%u (undefined)\n", nvram[6]);
882 	PRINT_PROC("Keyboard language: ");
883 	if (nvram[7] < ARRAY_SIZE(languages))
884 		PRINT_PROC("%s\n", languages[nvram[7]]);
885 	else
886 		PRINT_PROC("%u (undefined)\n", nvram[7]);
887 	PRINT_PROC("Date format      : ");
888 	PRINT_PROC(dateformat[nvram[8] & 7],
889 	    nvram[9] ? nvram[9] : '/', nvram[9] ? nvram[9] : '/');
890 	PRINT_PROC(", %dh clock\n", nvram[8] & 16 ? 24 : 12);
891 	PRINT_PROC("Boot delay       : ");
892 	if (nvram[10] == 0)
893 		PRINT_PROC("default");
894 	else
895 		PRINT_PROC("%ds%s\n", nvram[10],
896 		    nvram[10] < 8 ? ", no memory test" : "");
897 
898 	vmode = (nvram[14] << 8) || nvram[15];
899 	PRINT_PROC("Video mode       : %s colors, %d columns, %s %s monitor\n",
900 	    colors[vmode & 7],
901 	    vmode & 8 ? 80 : 40,
902 	    vmode & 16 ? "VGA" : "TV", vmode & 32 ? "PAL" : "NTSC");
903 	PRINT_PROC("                   %soverscan, compat. mode %s%s\n",
904 	    vmode & 64 ? "" : "no ",
905 	    vmode & 128 ? "on" : "off",
906 	    vmode & 256 ?
907 	    (vmode & 16 ? ", line doubling" : ", half screen") : "");
908 
909 	return 1;
910 }
911 #endif
912 
913 #endif /* MACH == ATARI */
914 
915 MODULE_LICENSE("GPL");
916 
917 EXPORT_SYMBOL(__nvram_read_byte);
918 EXPORT_SYMBOL(nvram_read_byte);
919 EXPORT_SYMBOL(__nvram_write_byte);
920 EXPORT_SYMBOL(nvram_write_byte);
921 EXPORT_SYMBOL(__nvram_check_checksum);
922 EXPORT_SYMBOL(nvram_check_checksum);
923 MODULE_ALIAS_MISCDEV(NVRAM_MINOR);
924