xref: /linux/drivers/char/nvram.c (revision 4dc7ccf7e9d9bca1989b840be9e8e84911387cf2)
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  * 	1.3	Wim Van Sebroeck: convert PRINT_PROC to seq_file
36  */
37 
38 #define NVRAM_VERSION	"1.3"
39 
40 #include <linux/module.h>
41 #include <linux/nvram.h>
42 
43 #define PC		1
44 #define ATARI		2
45 
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
54 
55 #if MACH == PC
56 
57 /* RTC in a PC */
58 #define CHECK_DRIVER_INIT()	1
59 
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)
65 
66 #define mach_check_checksum	pc_check_checksum
67 #define mach_set_checksum	pc_set_checksum
68 #define mach_proc_infos		pc_proc_infos
69 
70 #endif
71 
72 #if MACH == ATARI
73 
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))
79 
80 #define NVRAM_BYTES		50
81 
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
87 
88 #define mach_check_checksum	atari_check_checksum
89 #define mach_set_checksum	atari_set_checksum
90 #define mach_proc_infos		atari_proc_infos
91 
92 #endif
93 
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.)
98  */
99 
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/smp_lock.h>
113 
114 #include <asm/system.h>
115 
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 */
121 
122 static int mach_check_checksum(void);
123 static void mach_set_checksum(void);
124 
125 #ifdef CONFIG_PROC_FS
126 static void mach_proc_infos(unsigned char *contents, struct seq_file *seq,
127 								void *offset);
128 #endif
129 
130 /*
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).
134  *
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.
139  */
140 
141 unsigned char __nvram_read_byte(int i)
142 {
143 	return CMOS_READ(NVRAM_FIRST_BYTE + i);
144 }
145 EXPORT_SYMBOL(__nvram_read_byte);
146 
147 unsigned char nvram_read_byte(int i)
148 {
149 	unsigned long flags;
150 	unsigned char c;
151 
152 	spin_lock_irqsave(&rtc_lock, flags);
153 	c = __nvram_read_byte(i);
154 	spin_unlock_irqrestore(&rtc_lock, flags);
155 	return c;
156 }
157 EXPORT_SYMBOL(nvram_read_byte);
158 
159 /* This races nicely with trying to read with checksum checking (nvram_read) */
160 void __nvram_write_byte(unsigned char c, int i)
161 {
162 	CMOS_WRITE(c, NVRAM_FIRST_BYTE + i);
163 }
164 EXPORT_SYMBOL(__nvram_write_byte);
165 
166 void nvram_write_byte(unsigned char c, int i)
167 {
168 	unsigned long flags;
169 
170 	spin_lock_irqsave(&rtc_lock, flags);
171 	__nvram_write_byte(c, i);
172 	spin_unlock_irqrestore(&rtc_lock, flags);
173 }
174 EXPORT_SYMBOL(nvram_write_byte);
175 
176 int __nvram_check_checksum(void)
177 {
178 	return mach_check_checksum();
179 }
180 EXPORT_SYMBOL(__nvram_check_checksum);
181 
182 int nvram_check_checksum(void)
183 {
184 	unsigned long flags;
185 	int rv;
186 
187 	spin_lock_irqsave(&rtc_lock, flags);
188 	rv = __nvram_check_checksum();
189 	spin_unlock_irqrestore(&rtc_lock, flags);
190 	return rv;
191 }
192 EXPORT_SYMBOL(nvram_check_checksum);
193 
194 static void __nvram_set_checksum(void)
195 {
196 	mach_set_checksum();
197 }
198 
199 #if 0
200 void nvram_set_checksum(void)
201 {
202 	unsigned long flags;
203 
204 	spin_lock_irqsave(&rtc_lock, flags);
205 	__nvram_set_checksum();
206 	spin_unlock_irqrestore(&rtc_lock, flags);
207 }
208 #endif  /*  0  */
209 
210 /*
211  * The are the file operation function for user access to /dev/nvram
212  */
213 
214 static loff_t nvram_llseek(struct file *file, loff_t offset, int origin)
215 {
216 	switch (origin) {
217 	case 0:
218 		/* nothing to do */
219 		break;
220 	case 1:
221 		offset += file->f_pos;
222 		break;
223 	case 2:
224 		offset += NVRAM_BYTES;
225 		break;
226 	}
227 
228 	return (offset >= 0) ? (file->f_pos = offset) : -EINVAL;
229 }
230 
231 static ssize_t nvram_read(struct file *file, char __user *buf,
232 						size_t count, loff_t *ppos)
233 {
234 	unsigned char contents[NVRAM_BYTES];
235 	unsigned i = *ppos;
236 	unsigned char *tmp;
237 
238 	spin_lock_irq(&rtc_lock);
239 
240 	if (!__nvram_check_checksum())
241 		goto checksum_err;
242 
243 	for (tmp = contents; count-- > 0 && i < NVRAM_BYTES; ++i, ++tmp)
244 		*tmp = __nvram_read_byte(i);
245 
246 	spin_unlock_irq(&rtc_lock);
247 
248 	if (copy_to_user(buf, contents, tmp - contents))
249 		return -EFAULT;
250 
251 	*ppos = i;
252 
253 	return tmp - contents;
254 
255 checksum_err:
256 	spin_unlock_irq(&rtc_lock);
257 	return -EIO;
258 }
259 
260 static ssize_t nvram_write(struct file *file, const char __user *buf,
261 						size_t count, loff_t *ppos)
262 {
263 	unsigned char contents[NVRAM_BYTES];
264 	unsigned i = *ppos;
265 	unsigned char *tmp;
266 
267 	if (i >= NVRAM_BYTES)
268 		return 0;	/* Past EOF */
269 
270 	if (count > NVRAM_BYTES - i)
271 		count = NVRAM_BYTES - i;
272 	if (count > NVRAM_BYTES)
273 		return -EFAULT;	/* Can't happen, but prove it to gcc */
274 
275 	if (copy_from_user(contents, buf, count))
276 		return -EFAULT;
277 
278 	spin_lock_irq(&rtc_lock);
279 
280 	if (!__nvram_check_checksum())
281 		goto checksum_err;
282 
283 	for (tmp = contents; count--; ++i, ++tmp)
284 		__nvram_write_byte(*tmp, i);
285 
286 	__nvram_set_checksum();
287 
288 	spin_unlock_irq(&rtc_lock);
289 
290 	*ppos = i;
291 
292 	return tmp - contents;
293 
294 checksum_err:
295 	spin_unlock_irq(&rtc_lock);
296 	return -EIO;
297 }
298 
299 static int nvram_ioctl(struct inode *inode, struct file *file,
300 					unsigned int cmd, unsigned long arg)
301 {
302 	int i;
303 
304 	switch (cmd) {
305 
306 	case NVRAM_INIT:
307 		/* initialize NVRAM contents and checksum */
308 		if (!capable(CAP_SYS_ADMIN))
309 			return -EACCES;
310 
311 		spin_lock_irq(&rtc_lock);
312 
313 		for (i = 0; i < NVRAM_BYTES; ++i)
314 			__nvram_write_byte(0, i);
315 		__nvram_set_checksum();
316 
317 		spin_unlock_irq(&rtc_lock);
318 		return 0;
319 
320 	case NVRAM_SETCKS:
321 		/* just set checksum, contents unchanged (maybe useful after
322 		 * checksum garbaged somehow...) */
323 		if (!capable(CAP_SYS_ADMIN))
324 			return -EACCES;
325 
326 		spin_lock_irq(&rtc_lock);
327 		__nvram_set_checksum();
328 		spin_unlock_irq(&rtc_lock);
329 		return 0;
330 
331 	default:
332 		return -ENOTTY;
333 	}
334 }
335 
336 static int nvram_open(struct inode *inode, struct file *file)
337 {
338 	spin_lock(&nvram_state_lock);
339 
340 	if ((nvram_open_cnt && (file->f_flags & O_EXCL)) ||
341 	    (nvram_open_mode & NVRAM_EXCL) ||
342 	    ((file->f_mode & FMODE_WRITE) && (nvram_open_mode & NVRAM_WRITE))) {
343 		spin_unlock(&nvram_state_lock);
344 		return -EBUSY;
345 	}
346 
347 	if (file->f_flags & O_EXCL)
348 		nvram_open_mode |= NVRAM_EXCL;
349 	if (file->f_mode & FMODE_WRITE)
350 		nvram_open_mode |= NVRAM_WRITE;
351 	nvram_open_cnt++;
352 
353 	spin_unlock(&nvram_state_lock);
354 
355 	return 0;
356 }
357 
358 static int nvram_release(struct inode *inode, struct file *file)
359 {
360 	spin_lock(&nvram_state_lock);
361 
362 	nvram_open_cnt--;
363 
364 	/* if only one instance is open, clear the EXCL bit */
365 	if (nvram_open_mode & NVRAM_EXCL)
366 		nvram_open_mode &= ~NVRAM_EXCL;
367 	if (file->f_mode & FMODE_WRITE)
368 		nvram_open_mode &= ~NVRAM_WRITE;
369 
370 	spin_unlock(&nvram_state_lock);
371 
372 	return 0;
373 }
374 
375 #ifndef CONFIG_PROC_FS
376 static int nvram_add_proc_fs(void)
377 {
378 	return 0;
379 }
380 
381 #else
382 
383 static int nvram_proc_read(struct seq_file *seq, void *offset)
384 {
385 	unsigned char contents[NVRAM_BYTES];
386 	int i = 0;
387 
388 	spin_lock_irq(&rtc_lock);
389 	for (i = 0; i < NVRAM_BYTES; ++i)
390 		contents[i] = __nvram_read_byte(i);
391 	spin_unlock_irq(&rtc_lock);
392 
393 	mach_proc_infos(contents, seq, offset);
394 
395 	return 0;
396 }
397 
398 static int nvram_proc_open(struct inode *inode, struct file *file)
399 {
400 	return single_open(file, nvram_proc_read, NULL);
401 }
402 
403 static const struct file_operations nvram_proc_fops = {
404 	.owner		= THIS_MODULE,
405 	.open		= nvram_proc_open,
406 	.read		= seq_read,
407 	.llseek		= seq_lseek,
408 	.release	= single_release,
409 };
410 
411 static int nvram_add_proc_fs(void)
412 {
413 	if (!proc_create("driver/nvram", 0, NULL, &nvram_proc_fops))
414 		return -ENOMEM;
415 	return 0;
416 }
417 
418 #endif /* CONFIG_PROC_FS */
419 
420 static const struct file_operations nvram_fops = {
421 	.owner		= THIS_MODULE,
422 	.llseek		= nvram_llseek,
423 	.read		= nvram_read,
424 	.write		= nvram_write,
425 	.ioctl		= nvram_ioctl,
426 	.open		= nvram_open,
427 	.release	= nvram_release,
428 };
429 
430 static struct miscdevice nvram_dev = {
431 	NVRAM_MINOR,
432 	"nvram",
433 	&nvram_fops
434 };
435 
436 static int __init nvram_init(void)
437 {
438 	int ret;
439 
440 	/* First test whether the driver should init at all */
441 	if (!CHECK_DRIVER_INIT())
442 		return -ENODEV;
443 
444 	ret = misc_register(&nvram_dev);
445 	if (ret) {
446 		printk(KERN_ERR "nvram: can't misc_register on minor=%d\n",
447 		    NVRAM_MINOR);
448 		goto out;
449 	}
450 	ret = nvram_add_proc_fs();
451 	if (ret) {
452 		printk(KERN_ERR "nvram: can't create /proc/driver/nvram\n");
453 		goto outmisc;
454 	}
455 	ret = 0;
456 	printk(KERN_INFO "Non-volatile memory driver v" NVRAM_VERSION "\n");
457 out:
458 	return ret;
459 outmisc:
460 	misc_deregister(&nvram_dev);
461 	goto out;
462 }
463 
464 static void __exit nvram_cleanup_module(void)
465 {
466 	remove_proc_entry("driver/nvram", NULL);
467 	misc_deregister(&nvram_dev);
468 }
469 
470 module_init(nvram_init);
471 module_exit(nvram_cleanup_module);
472 
473 /*
474  * Machine specific functions
475  */
476 
477 #if MACH == PC
478 
479 static int pc_check_checksum(void)
480 {
481 	int i;
482 	unsigned short sum = 0;
483 	unsigned short expect;
484 
485 	for (i = PC_CKS_RANGE_START; i <= PC_CKS_RANGE_END; ++i)
486 		sum += __nvram_read_byte(i);
487 	expect = __nvram_read_byte(PC_CKS_LOC)<<8 |
488 	    __nvram_read_byte(PC_CKS_LOC+1);
489 	return (sum & 0xffff) == expect;
490 }
491 
492 static void pc_set_checksum(void)
493 {
494 	int i;
495 	unsigned short sum = 0;
496 
497 	for (i = PC_CKS_RANGE_START; i <= PC_CKS_RANGE_END; ++i)
498 		sum += __nvram_read_byte(i);
499 	__nvram_write_byte(sum >> 8, PC_CKS_LOC);
500 	__nvram_write_byte(sum & 0xff, PC_CKS_LOC + 1);
501 }
502 
503 #ifdef CONFIG_PROC_FS
504 
505 static char *floppy_types[] = {
506 	"none", "5.25'' 360k", "5.25'' 1.2M", "3.5'' 720k", "3.5'' 1.44M",
507 	"3.5'' 2.88M", "3.5'' 2.88M"
508 };
509 
510 static char *gfx_types[] = {
511 	"EGA, VGA, ... (with BIOS)",
512 	"CGA (40 cols)",
513 	"CGA (80 cols)",
514 	"monochrome",
515 };
516 
517 static void pc_proc_infos(unsigned char *nvram, struct seq_file *seq,
518 								void *offset)
519 {
520 	int checksum;
521 	int type;
522 
523 	spin_lock_irq(&rtc_lock);
524 	checksum = __nvram_check_checksum();
525 	spin_unlock_irq(&rtc_lock);
526 
527 	seq_printf(seq, "Checksum status: %svalid\n", checksum ? "" : "not ");
528 
529 	seq_printf(seq, "# floppies     : %d\n",
530 	    (nvram[6] & 1) ? (nvram[6] >> 6) + 1 : 0);
531 	seq_printf(seq, "Floppy 0 type  : ");
532 	type = nvram[2] >> 4;
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);
537 	seq_printf(seq, "Floppy 1 type  : ");
538 	type = nvram[2] & 0x0f;
539 	if (type < ARRAY_SIZE(floppy_types))
540 		seq_printf(seq, "%s\n", floppy_types[type]);
541 	else
542 		seq_printf(seq, "%d (unknown)\n", type);
543 
544 	seq_printf(seq, "HD 0 type      : ");
545 	type = nvram[4] >> 4;
546 	if (type)
547 		seq_printf(seq, "%02x\n", type == 0x0f ? nvram[11] : type);
548 	else
549 		seq_printf(seq, "none\n");
550 
551 	seq_printf(seq, "HD 1 type      : ");
552 	type = nvram[4] & 0x0f;
553 	if (type)
554 		seq_printf(seq, "%02x\n", type == 0x0f ? nvram[12] : type);
555 	else
556 		seq_printf(seq, "none\n");
557 
558 	seq_printf(seq, "HD type 48 data: %d/%d/%d C/H/S, precomp %d, lz %d\n",
559 	    nvram[18] | (nvram[19] << 8),
560 	    nvram[20], nvram[25],
561 	    nvram[21] | (nvram[22] << 8), nvram[23] | (nvram[24] << 8));
562 	seq_printf(seq, "HD type 49 data: %d/%d/%d C/H/S, precomp %d, lz %d\n",
563 	    nvram[39] | (nvram[40] << 8),
564 	    nvram[41], nvram[46],
565 	    nvram[42] | (nvram[43] << 8), nvram[44] | (nvram[45] << 8));
566 
567 	seq_printf(seq, "DOS base memory: %d kB\n", nvram[7] | (nvram[8] << 8));
568 	seq_printf(seq, "Extended memory: %d kB (configured), %d kB (tested)\n",
569 	    nvram[9] | (nvram[10] << 8), nvram[34] | (nvram[35] << 8));
570 
571 	seq_printf(seq, "Gfx adapter    : %s\n",
572 	    gfx_types[(nvram[6] >> 4) & 3]);
573 
574 	seq_printf(seq, "FPU            : %sinstalled\n",
575 	    (nvram[6] & 2) ? "" : "not ");
576 
577 	return;
578 }
579 #endif
580 
581 #endif /* MACH == PC */
582 
583 #if MACH == ATARI
584 
585 static int atari_check_checksum(void)
586 {
587 	int i;
588 	unsigned char sum = 0;
589 
590 	for (i = ATARI_CKS_RANGE_START; i <= ATARI_CKS_RANGE_END; ++i)
591 		sum += __nvram_read_byte(i);
592 	return (__nvram_read_byte(ATARI_CKS_LOC) == (~sum & 0xff)) &&
593 	    (__nvram_read_byte(ATARI_CKS_LOC + 1) == (sum & 0xff));
594 }
595 
596 static void atari_set_checksum(void)
597 {
598 	int i;
599 	unsigned char sum = 0;
600 
601 	for (i = ATARI_CKS_RANGE_START; i <= ATARI_CKS_RANGE_END; ++i)
602 		sum += __nvram_read_byte(i);
603 	__nvram_write_byte(~sum, ATARI_CKS_LOC);
604 	__nvram_write_byte(sum, ATARI_CKS_LOC + 1);
605 }
606 
607 #ifdef CONFIG_PROC_FS
608 
609 static struct {
610 	unsigned char val;
611 	char *name;
612 } boot_prefs[] = {
613 	{ 0x80, "TOS" },
614 	{ 0x40, "ASV" },
615 	{ 0x20, "NetBSD (?)" },
616 	{ 0x10, "Linux" },
617 	{ 0x00, "unspecified" }
618 };
619 
620 static char *languages[] = {
621 	"English (US)",
622 	"German",
623 	"French",
624 	"English (UK)",
625 	"Spanish",
626 	"Italian",
627 	"6 (undefined)",
628 	"Swiss (French)",
629 	"Swiss (German)"
630 };
631 
632 static char *dateformat[] = {
633 	"MM%cDD%cYY",
634 	"DD%cMM%cYY",
635 	"YY%cMM%cDD",
636 	"YY%cDD%cMM",
637 	"4 (undefined)",
638 	"5 (undefined)",
639 	"6 (undefined)",
640 	"7 (undefined)"
641 };
642 
643 static char *colors[] = {
644 	"2", "4", "16", "256", "65536", "??", "??", "??"
645 };
646 
647 static void atari_proc_infos(unsigned char *nvram, struct seq_file *seq,
648 								void *offset)
649 {
650 	int checksum = nvram_check_checksum();
651 	int i;
652 	unsigned vmode;
653 
654 	seq_printf(seq, "Checksum status  : %svalid\n", checksum ? "" : "not ");
655 
656 	seq_printf(seq, "Boot preference  : ");
657 	for (i = ARRAY_SIZE(boot_prefs) - 1; i >= 0; --i) {
658 		if (nvram[1] == boot_prefs[i].val) {
659 			seq_printf(seq, "%s\n", boot_prefs[i].name);
660 			break;
661 		}
662 	}
663 	if (i < 0)
664 		seq_printf(seq, "0x%02x (undefined)\n", nvram[1]);
665 
666 	seq_printf(seq, "SCSI arbitration : %s\n",
667 	    (nvram[16] & 0x80) ? "on" : "off");
668 	seq_printf(seq, "SCSI host ID     : ");
669 	if (nvram[16] & 0x80)
670 		seq_printf(seq, "%d\n", nvram[16] & 7);
671 	else
672 		seq_printf(seq, "n/a\n");
673 
674 	/* the following entries are defined only for the Falcon */
675 	if ((atari_mch_cookie >> 16) != ATARI_MCH_FALCON)
676 		return;
677 
678 	seq_printf(seq, "OS language      : ");
679 	if (nvram[6] < ARRAY_SIZE(languages))
680 		seq_printf(seq, "%s\n", languages[nvram[6]]);
681 	else
682 		seq_printf(seq, "%u (undefined)\n", nvram[6]);
683 	seq_printf(seq, "Keyboard language: ");
684 	if (nvram[7] < ARRAY_SIZE(languages))
685 		seq_printf(seq, "%s\n", languages[nvram[7]]);
686 	else
687 		seq_printf(seq, "%u (undefined)\n", nvram[7]);
688 	seq_printf(seq, "Date format      : ");
689 	seq_printf(seq, dateformat[nvram[8] & 7],
690 	    nvram[9] ? nvram[9] : '/', nvram[9] ? nvram[9] : '/');
691 	seq_printf(seq, ", %dh clock\n", nvram[8] & 16 ? 24 : 12);
692 	seq_printf(seq, "Boot delay       : ");
693 	if (nvram[10] == 0)
694 		seq_printf(seq, "default");
695 	else
696 		seq_printf(seq, "%ds%s\n", nvram[10],
697 		    nvram[10] < 8 ? ", no memory test" : "");
698 
699 	vmode = (nvram[14] << 8) || nvram[15];
700 	seq_printf(seq,
701 	    "Video mode       : %s colors, %d columns, %s %s monitor\n",
702 	    colors[vmode & 7],
703 	    vmode & 8 ? 80 : 40,
704 	    vmode & 16 ? "VGA" : "TV", vmode & 32 ? "PAL" : "NTSC");
705 	seq_printf(seq, "                   %soverscan, compat. mode %s%s\n",
706 	    vmode & 64 ? "" : "no ",
707 	    vmode & 128 ? "on" : "off",
708 	    vmode & 256 ?
709 	    (vmode & 16 ? ", line doubling" : ", half screen") : "");
710 
711 	return;
712 }
713 #endif
714 
715 #endif /* MACH == ATARI */
716 
717 MODULE_LICENSE("GPL");
718 MODULE_ALIAS_MISCDEV(NVRAM_MINOR);
719