xref: /openbmc/linux/drivers/char/nvram.c (revision 8c749ce9)
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 kernel/time/ntp.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/mutex.h>
113 #include <linux/pagemap.h>
114 
115 
116 static DEFINE_MUTEX(nvram_mutex);
117 static DEFINE_SPINLOCK(nvram_state_lock);
118 static int nvram_open_cnt;	/* #times opened */
119 static int nvram_open_mode;	/* special open modes */
120 #define NVRAM_WRITE		1 /* opened for writing (exclusive) */
121 #define NVRAM_EXCL		2 /* opened with O_EXCL */
122 
123 static int mach_check_checksum(void);
124 static void mach_set_checksum(void);
125 
126 #ifdef CONFIG_PROC_FS
127 static void mach_proc_infos(unsigned char *contents, struct seq_file *seq,
128 								void *offset);
129 #endif
130 
131 /*
132  * These functions are provided to be called internally or by other parts of
133  * the kernel. It's up to the caller to ensure correct checksum before reading
134  * or after writing (needs to be done only once).
135  *
136  * It is worth noting that these functions all access bytes of general
137  * purpose memory in the NVRAM - that is to say, they all add the
138  * NVRAM_FIRST_BYTE offset.  Pass them offsets into NVRAM as if you did not
139  * know about the RTC cruft.
140  */
141 
142 unsigned char __nvram_read_byte(int i)
143 {
144 	return CMOS_READ(NVRAM_FIRST_BYTE + i);
145 }
146 EXPORT_SYMBOL(__nvram_read_byte);
147 
148 unsigned char nvram_read_byte(int i)
149 {
150 	unsigned long flags;
151 	unsigned char c;
152 
153 	spin_lock_irqsave(&rtc_lock, flags);
154 	c = __nvram_read_byte(i);
155 	spin_unlock_irqrestore(&rtc_lock, flags);
156 	return c;
157 }
158 EXPORT_SYMBOL(nvram_read_byte);
159 
160 /* This races nicely with trying to read with checksum checking (nvram_read) */
161 void __nvram_write_byte(unsigned char c, int i)
162 {
163 	CMOS_WRITE(c, NVRAM_FIRST_BYTE + i);
164 }
165 EXPORT_SYMBOL(__nvram_write_byte);
166 
167 void nvram_write_byte(unsigned char c, int i)
168 {
169 	unsigned long flags;
170 
171 	spin_lock_irqsave(&rtc_lock, flags);
172 	__nvram_write_byte(c, i);
173 	spin_unlock_irqrestore(&rtc_lock, flags);
174 }
175 EXPORT_SYMBOL(nvram_write_byte);
176 
177 int __nvram_check_checksum(void)
178 {
179 	return mach_check_checksum();
180 }
181 EXPORT_SYMBOL(__nvram_check_checksum);
182 
183 int nvram_check_checksum(void)
184 {
185 	unsigned long flags;
186 	int rv;
187 
188 	spin_lock_irqsave(&rtc_lock, flags);
189 	rv = __nvram_check_checksum();
190 	spin_unlock_irqrestore(&rtc_lock, flags);
191 	return rv;
192 }
193 EXPORT_SYMBOL(nvram_check_checksum);
194 
195 static void __nvram_set_checksum(void)
196 {
197 	mach_set_checksum();
198 }
199 
200 #if 0
201 void nvram_set_checksum(void)
202 {
203 	unsigned long flags;
204 
205 	spin_lock_irqsave(&rtc_lock, flags);
206 	__nvram_set_checksum();
207 	spin_unlock_irqrestore(&rtc_lock, flags);
208 }
209 #endif  /*  0  */
210 
211 /*
212  * The are the file operation function for user access to /dev/nvram
213  */
214 
215 static loff_t nvram_llseek(struct file *file, loff_t offset, int origin)
216 {
217 	return generic_file_llseek_size(file, offset, origin, MAX_LFS_FILESIZE,
218 					NVRAM_BYTES);
219 }
220 
221 static ssize_t nvram_read(struct file *file, char __user *buf,
222 						size_t count, loff_t *ppos)
223 {
224 	unsigned char contents[NVRAM_BYTES];
225 	unsigned i = *ppos;
226 	unsigned char *tmp;
227 
228 	spin_lock_irq(&rtc_lock);
229 
230 	if (!__nvram_check_checksum())
231 		goto checksum_err;
232 
233 	for (tmp = contents; count-- > 0 && i < NVRAM_BYTES; ++i, ++tmp)
234 		*tmp = __nvram_read_byte(i);
235 
236 	spin_unlock_irq(&rtc_lock);
237 
238 	if (copy_to_user(buf, contents, tmp - contents))
239 		return -EFAULT;
240 
241 	*ppos = i;
242 
243 	return tmp - contents;
244 
245 checksum_err:
246 	spin_unlock_irq(&rtc_lock);
247 	return -EIO;
248 }
249 
250 static ssize_t nvram_write(struct file *file, const char __user *buf,
251 						size_t count, loff_t *ppos)
252 {
253 	unsigned char contents[NVRAM_BYTES];
254 	unsigned i = *ppos;
255 	unsigned char *tmp;
256 
257 	if (i >= NVRAM_BYTES)
258 		return 0;	/* Past EOF */
259 
260 	if (count > NVRAM_BYTES - i)
261 		count = NVRAM_BYTES - i;
262 	if (count > NVRAM_BYTES)
263 		return -EFAULT;	/* Can't happen, but prove it to gcc */
264 
265 	if (copy_from_user(contents, buf, count))
266 		return -EFAULT;
267 
268 	spin_lock_irq(&rtc_lock);
269 
270 	if (!__nvram_check_checksum())
271 		goto checksum_err;
272 
273 	for (tmp = contents; count--; ++i, ++tmp)
274 		__nvram_write_byte(*tmp, i);
275 
276 	__nvram_set_checksum();
277 
278 	spin_unlock_irq(&rtc_lock);
279 
280 	*ppos = i;
281 
282 	return tmp - contents;
283 
284 checksum_err:
285 	spin_unlock_irq(&rtc_lock);
286 	return -EIO;
287 }
288 
289 static long nvram_ioctl(struct file *file, unsigned int cmd,
290 			unsigned long arg)
291 {
292 	int i;
293 
294 	switch (cmd) {
295 
296 	case NVRAM_INIT:
297 		/* initialize NVRAM contents and checksum */
298 		if (!capable(CAP_SYS_ADMIN))
299 			return -EACCES;
300 
301 		mutex_lock(&nvram_mutex);
302 		spin_lock_irq(&rtc_lock);
303 
304 		for (i = 0; i < NVRAM_BYTES; ++i)
305 			__nvram_write_byte(0, i);
306 		__nvram_set_checksum();
307 
308 		spin_unlock_irq(&rtc_lock);
309 		mutex_unlock(&nvram_mutex);
310 		return 0;
311 
312 	case NVRAM_SETCKS:
313 		/* just set checksum, contents unchanged (maybe useful after
314 		 * checksum garbaged somehow...) */
315 		if (!capable(CAP_SYS_ADMIN))
316 			return -EACCES;
317 
318 		mutex_lock(&nvram_mutex);
319 		spin_lock_irq(&rtc_lock);
320 		__nvram_set_checksum();
321 		spin_unlock_irq(&rtc_lock);
322 		mutex_unlock(&nvram_mutex);
323 		return 0;
324 
325 	default:
326 		return -ENOTTY;
327 	}
328 }
329 
330 static int nvram_open(struct inode *inode, struct file *file)
331 {
332 	spin_lock(&nvram_state_lock);
333 
334 	if ((nvram_open_cnt && (file->f_flags & O_EXCL)) ||
335 	    (nvram_open_mode & NVRAM_EXCL) ||
336 	    ((file->f_mode & FMODE_WRITE) && (nvram_open_mode & NVRAM_WRITE))) {
337 		spin_unlock(&nvram_state_lock);
338 		return -EBUSY;
339 	}
340 
341 	if (file->f_flags & O_EXCL)
342 		nvram_open_mode |= NVRAM_EXCL;
343 	if (file->f_mode & FMODE_WRITE)
344 		nvram_open_mode |= NVRAM_WRITE;
345 	nvram_open_cnt++;
346 
347 	spin_unlock(&nvram_state_lock);
348 
349 	return 0;
350 }
351 
352 static int nvram_release(struct inode *inode, struct file *file)
353 {
354 	spin_lock(&nvram_state_lock);
355 
356 	nvram_open_cnt--;
357 
358 	/* if only one instance is open, clear the EXCL bit */
359 	if (nvram_open_mode & NVRAM_EXCL)
360 		nvram_open_mode &= ~NVRAM_EXCL;
361 	if (file->f_mode & FMODE_WRITE)
362 		nvram_open_mode &= ~NVRAM_WRITE;
363 
364 	spin_unlock(&nvram_state_lock);
365 
366 	return 0;
367 }
368 
369 #ifndef CONFIG_PROC_FS
370 static int nvram_add_proc_fs(void)
371 {
372 	return 0;
373 }
374 
375 #else
376 
377 static int nvram_proc_read(struct seq_file *seq, void *offset)
378 {
379 	unsigned char contents[NVRAM_BYTES];
380 	int i = 0;
381 
382 	spin_lock_irq(&rtc_lock);
383 	for (i = 0; i < NVRAM_BYTES; ++i)
384 		contents[i] = __nvram_read_byte(i);
385 	spin_unlock_irq(&rtc_lock);
386 
387 	mach_proc_infos(contents, seq, offset);
388 
389 	return 0;
390 }
391 
392 static int nvram_proc_open(struct inode *inode, struct file *file)
393 {
394 	return single_open(file, nvram_proc_read, NULL);
395 }
396 
397 static const struct file_operations nvram_proc_fops = {
398 	.owner		= THIS_MODULE,
399 	.open		= nvram_proc_open,
400 	.read		= seq_read,
401 	.llseek		= seq_lseek,
402 	.release	= single_release,
403 };
404 
405 static int nvram_add_proc_fs(void)
406 {
407 	if (!proc_create("driver/nvram", 0, NULL, &nvram_proc_fops))
408 		return -ENOMEM;
409 	return 0;
410 }
411 
412 #endif /* CONFIG_PROC_FS */
413 
414 static const struct file_operations nvram_fops = {
415 	.owner		= THIS_MODULE,
416 	.llseek		= nvram_llseek,
417 	.read		= nvram_read,
418 	.write		= nvram_write,
419 	.unlocked_ioctl	= nvram_ioctl,
420 	.open		= nvram_open,
421 	.release	= nvram_release,
422 };
423 
424 static struct miscdevice nvram_dev = {
425 	NVRAM_MINOR,
426 	"nvram",
427 	&nvram_fops
428 };
429 
430 static int __init nvram_init(void)
431 {
432 	int ret;
433 
434 	/* First test whether the driver should init at all */
435 	if (!CHECK_DRIVER_INIT())
436 		return -ENODEV;
437 
438 	ret = misc_register(&nvram_dev);
439 	if (ret) {
440 		printk(KERN_ERR "nvram: can't misc_register on minor=%d\n",
441 		    NVRAM_MINOR);
442 		goto out;
443 	}
444 	ret = nvram_add_proc_fs();
445 	if (ret) {
446 		printk(KERN_ERR "nvram: can't create /proc/driver/nvram\n");
447 		goto outmisc;
448 	}
449 	ret = 0;
450 	printk(KERN_INFO "Non-volatile memory driver v" NVRAM_VERSION "\n");
451 out:
452 	return ret;
453 outmisc:
454 	misc_deregister(&nvram_dev);
455 	goto out;
456 }
457 
458 static void __exit nvram_cleanup_module(void)
459 {
460 	remove_proc_entry("driver/nvram", NULL);
461 	misc_deregister(&nvram_dev);
462 }
463 
464 module_init(nvram_init);
465 module_exit(nvram_cleanup_module);
466 
467 /*
468  * Machine specific functions
469  */
470 
471 #if MACH == PC
472 
473 static int pc_check_checksum(void)
474 {
475 	int i;
476 	unsigned short sum = 0;
477 	unsigned short expect;
478 
479 	for (i = PC_CKS_RANGE_START; i <= PC_CKS_RANGE_END; ++i)
480 		sum += __nvram_read_byte(i);
481 	expect = __nvram_read_byte(PC_CKS_LOC)<<8 |
482 	    __nvram_read_byte(PC_CKS_LOC+1);
483 	return (sum & 0xffff) == expect;
484 }
485 
486 static void pc_set_checksum(void)
487 {
488 	int i;
489 	unsigned short sum = 0;
490 
491 	for (i = PC_CKS_RANGE_START; i <= PC_CKS_RANGE_END; ++i)
492 		sum += __nvram_read_byte(i);
493 	__nvram_write_byte(sum >> 8, PC_CKS_LOC);
494 	__nvram_write_byte(sum & 0xff, PC_CKS_LOC + 1);
495 }
496 
497 #ifdef CONFIG_PROC_FS
498 
499 static char *floppy_types[] = {
500 	"none", "5.25'' 360k", "5.25'' 1.2M", "3.5'' 720k", "3.5'' 1.44M",
501 	"3.5'' 2.88M", "3.5'' 2.88M"
502 };
503 
504 static char *gfx_types[] = {
505 	"EGA, VGA, ... (with BIOS)",
506 	"CGA (40 cols)",
507 	"CGA (80 cols)",
508 	"monochrome",
509 };
510 
511 static void pc_proc_infos(unsigned char *nvram, struct seq_file *seq,
512 								void *offset)
513 {
514 	int checksum;
515 	int type;
516 
517 	spin_lock_irq(&rtc_lock);
518 	checksum = __nvram_check_checksum();
519 	spin_unlock_irq(&rtc_lock);
520 
521 	seq_printf(seq, "Checksum status: %svalid\n", checksum ? "" : "not ");
522 
523 	seq_printf(seq, "# floppies     : %d\n",
524 	    (nvram[6] & 1) ? (nvram[6] >> 6) + 1 : 0);
525 	seq_printf(seq, "Floppy 0 type  : ");
526 	type = nvram[2] >> 4;
527 	if (type < ARRAY_SIZE(floppy_types))
528 		seq_printf(seq, "%s\n", floppy_types[type]);
529 	else
530 		seq_printf(seq, "%d (unknown)\n", type);
531 	seq_printf(seq, "Floppy 1 type  : ");
532 	type = nvram[2] & 0x0f;
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 
538 	seq_printf(seq, "HD 0 type      : ");
539 	type = nvram[4] >> 4;
540 	if (type)
541 		seq_printf(seq, "%02x\n", type == 0x0f ? nvram[11] : type);
542 	else
543 		seq_printf(seq, "none\n");
544 
545 	seq_printf(seq, "HD 1 type      : ");
546 	type = nvram[4] & 0x0f;
547 	if (type)
548 		seq_printf(seq, "%02x\n", type == 0x0f ? nvram[12] : type);
549 	else
550 		seq_printf(seq, "none\n");
551 
552 	seq_printf(seq, "HD type 48 data: %d/%d/%d C/H/S, precomp %d, lz %d\n",
553 	    nvram[18] | (nvram[19] << 8),
554 	    nvram[20], nvram[25],
555 	    nvram[21] | (nvram[22] << 8), nvram[23] | (nvram[24] << 8));
556 	seq_printf(seq, "HD type 49 data: %d/%d/%d C/H/S, precomp %d, lz %d\n",
557 	    nvram[39] | (nvram[40] << 8),
558 	    nvram[41], nvram[46],
559 	    nvram[42] | (nvram[43] << 8), nvram[44] | (nvram[45] << 8));
560 
561 	seq_printf(seq, "DOS base memory: %d kB\n", nvram[7] | (nvram[8] << 8));
562 	seq_printf(seq, "Extended memory: %d kB (configured), %d kB (tested)\n",
563 	    nvram[9] | (nvram[10] << 8), nvram[34] | (nvram[35] << 8));
564 
565 	seq_printf(seq, "Gfx adapter    : %s\n",
566 	    gfx_types[(nvram[6] >> 4) & 3]);
567 
568 	seq_printf(seq, "FPU            : %sinstalled\n",
569 	    (nvram[6] & 2) ? "" : "not ");
570 
571 	return;
572 }
573 #endif
574 
575 #endif /* MACH == PC */
576 
577 #if MACH == ATARI
578 
579 static int atari_check_checksum(void)
580 {
581 	int i;
582 	unsigned char sum = 0;
583 
584 	for (i = ATARI_CKS_RANGE_START; i <= ATARI_CKS_RANGE_END; ++i)
585 		sum += __nvram_read_byte(i);
586 	return (__nvram_read_byte(ATARI_CKS_LOC) == (~sum & 0xff)) &&
587 	    (__nvram_read_byte(ATARI_CKS_LOC + 1) == (sum & 0xff));
588 }
589 
590 static void atari_set_checksum(void)
591 {
592 	int i;
593 	unsigned char sum = 0;
594 
595 	for (i = ATARI_CKS_RANGE_START; i <= ATARI_CKS_RANGE_END; ++i)
596 		sum += __nvram_read_byte(i);
597 	__nvram_write_byte(~sum, ATARI_CKS_LOC);
598 	__nvram_write_byte(sum, ATARI_CKS_LOC + 1);
599 }
600 
601 #ifdef CONFIG_PROC_FS
602 
603 static struct {
604 	unsigned char val;
605 	char *name;
606 } boot_prefs[] = {
607 	{ 0x80, "TOS" },
608 	{ 0x40, "ASV" },
609 	{ 0x20, "NetBSD (?)" },
610 	{ 0x10, "Linux" },
611 	{ 0x00, "unspecified" }
612 };
613 
614 static char *languages[] = {
615 	"English (US)",
616 	"German",
617 	"French",
618 	"English (UK)",
619 	"Spanish",
620 	"Italian",
621 	"6 (undefined)",
622 	"Swiss (French)",
623 	"Swiss (German)"
624 };
625 
626 static char *dateformat[] = {
627 	"MM%cDD%cYY",
628 	"DD%cMM%cYY",
629 	"YY%cMM%cDD",
630 	"YY%cDD%cMM",
631 	"4 (undefined)",
632 	"5 (undefined)",
633 	"6 (undefined)",
634 	"7 (undefined)"
635 };
636 
637 static char *colors[] = {
638 	"2", "4", "16", "256", "65536", "??", "??", "??"
639 };
640 
641 static void atari_proc_infos(unsigned char *nvram, struct seq_file *seq,
642 								void *offset)
643 {
644 	int checksum = nvram_check_checksum();
645 	int i;
646 	unsigned vmode;
647 
648 	seq_printf(seq, "Checksum status  : %svalid\n", checksum ? "" : "not ");
649 
650 	seq_printf(seq, "Boot preference  : ");
651 	for (i = ARRAY_SIZE(boot_prefs) - 1; i >= 0; --i) {
652 		if (nvram[1] == boot_prefs[i].val) {
653 			seq_printf(seq, "%s\n", boot_prefs[i].name);
654 			break;
655 		}
656 	}
657 	if (i < 0)
658 		seq_printf(seq, "0x%02x (undefined)\n", nvram[1]);
659 
660 	seq_printf(seq, "SCSI arbitration : %s\n",
661 	    (nvram[16] & 0x80) ? "on" : "off");
662 	seq_printf(seq, "SCSI host ID     : ");
663 	if (nvram[16] & 0x80)
664 		seq_printf(seq, "%d\n", nvram[16] & 7);
665 	else
666 		seq_printf(seq, "n/a\n");
667 
668 	/* the following entries are defined only for the Falcon */
669 	if ((atari_mch_cookie >> 16) != ATARI_MCH_FALCON)
670 		return;
671 
672 	seq_printf(seq, "OS language      : ");
673 	if (nvram[6] < ARRAY_SIZE(languages))
674 		seq_printf(seq, "%s\n", languages[nvram[6]]);
675 	else
676 		seq_printf(seq, "%u (undefined)\n", nvram[6]);
677 	seq_printf(seq, "Keyboard language: ");
678 	if (nvram[7] < ARRAY_SIZE(languages))
679 		seq_printf(seq, "%s\n", languages[nvram[7]]);
680 	else
681 		seq_printf(seq, "%u (undefined)\n", nvram[7]);
682 	seq_printf(seq, "Date format      : ");
683 	seq_printf(seq, dateformat[nvram[8] & 7],
684 	    nvram[9] ? nvram[9] : '/', nvram[9] ? nvram[9] : '/');
685 	seq_printf(seq, ", %dh clock\n", nvram[8] & 16 ? 24 : 12);
686 	seq_printf(seq, "Boot delay       : ");
687 	if (nvram[10] == 0)
688 		seq_printf(seq, "default");
689 	else
690 		seq_printf(seq, "%ds%s\n", nvram[10],
691 		    nvram[10] < 8 ? ", no memory test" : "");
692 
693 	vmode = (nvram[14] << 8) | nvram[15];
694 	seq_printf(seq,
695 	    "Video mode       : %s colors, %d columns, %s %s monitor\n",
696 	    colors[vmode & 7],
697 	    vmode & 8 ? 80 : 40,
698 	    vmode & 16 ? "VGA" : "TV", vmode & 32 ? "PAL" : "NTSC");
699 	seq_printf(seq, "                   %soverscan, compat. mode %s%s\n",
700 	    vmode & 64 ? "" : "no ",
701 	    vmode & 128 ? "on" : "off",
702 	    vmode & 256 ?
703 	    (vmode & 16 ? ", line doubling" : ", half screen") : "");
704 
705 	return;
706 }
707 #endif
708 
709 #endif /* MACH == ATARI */
710 
711 MODULE_LICENSE("GPL");
712 MODULE_ALIAS_MISCDEV(NVRAM_MINOR);
713