xref: /openbmc/linux/drivers/char/nvram.c (revision 79a56ed0)
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/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>
113 #include <linux/smp_lock.h>
114 
115 #include <asm/system.h>
116 
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 	switch (origin) {
218 	case 0:
219 		/* nothing to do */
220 		break;
221 	case 1:
222 		offset += file->f_pos;
223 		break;
224 	case 2:
225 		offset += NVRAM_BYTES;
226 		break;
227 	}
228 
229 	return (offset >= 0) ? (file->f_pos = offset) : -EINVAL;
230 }
231 
232 static ssize_t nvram_read(struct file *file, char __user *buf,
233 						size_t count, loff_t *ppos)
234 {
235 	unsigned char contents[NVRAM_BYTES];
236 	unsigned i = *ppos;
237 	unsigned char *tmp;
238 
239 	spin_lock_irq(&rtc_lock);
240 
241 	if (!__nvram_check_checksum())
242 		goto checksum_err;
243 
244 	for (tmp = contents; count-- > 0 && i < NVRAM_BYTES; ++i, ++tmp)
245 		*tmp = __nvram_read_byte(i);
246 
247 	spin_unlock_irq(&rtc_lock);
248 
249 	if (copy_to_user(buf, contents, tmp - contents))
250 		return -EFAULT;
251 
252 	*ppos = i;
253 
254 	return tmp - contents;
255 
256 checksum_err:
257 	spin_unlock_irq(&rtc_lock);
258 	return -EIO;
259 }
260 
261 static ssize_t nvram_write(struct file *file, const char __user *buf,
262 						size_t count, loff_t *ppos)
263 {
264 	unsigned char contents[NVRAM_BYTES];
265 	unsigned i = *ppos;
266 	unsigned char *tmp;
267 	int len;
268 
269 	len = (NVRAM_BYTES - i) < count ? (NVRAM_BYTES - i) : count;
270 	if (copy_from_user(contents, buf, len))
271 		return -EFAULT;
272 
273 	spin_lock_irq(&rtc_lock);
274 
275 	if (!__nvram_check_checksum())
276 		goto checksum_err;
277 
278 	for (tmp = contents; count-- > 0 && i < NVRAM_BYTES; ++i, ++tmp)
279 		__nvram_write_byte(*tmp, i);
280 
281 	__nvram_set_checksum();
282 
283 	spin_unlock_irq(&rtc_lock);
284 
285 	*ppos = i;
286 
287 	return tmp - contents;
288 
289 checksum_err:
290 	spin_unlock_irq(&rtc_lock);
291 	return -EIO;
292 }
293 
294 static int nvram_ioctl(struct inode *inode, struct file *file,
295 					unsigned int cmd, unsigned long arg)
296 {
297 	int i;
298 
299 	switch (cmd) {
300 
301 	case NVRAM_INIT:
302 		/* initialize NVRAM contents and checksum */
303 		if (!capable(CAP_SYS_ADMIN))
304 			return -EACCES;
305 
306 		spin_lock_irq(&rtc_lock);
307 
308 		for (i = 0; i < NVRAM_BYTES; ++i)
309 			__nvram_write_byte(0, i);
310 		__nvram_set_checksum();
311 
312 		spin_unlock_irq(&rtc_lock);
313 		return 0;
314 
315 	case NVRAM_SETCKS:
316 		/* just set checksum, contents unchanged (maybe useful after
317 		 * checksum garbaged somehow...) */
318 		if (!capable(CAP_SYS_ADMIN))
319 			return -EACCES;
320 
321 		spin_lock_irq(&rtc_lock);
322 		__nvram_set_checksum();
323 		spin_unlock_irq(&rtc_lock);
324 		return 0;
325 
326 	default:
327 		return -ENOTTY;
328 	}
329 }
330 
331 static int nvram_open(struct inode *inode, struct file *file)
332 {
333 	lock_kernel();
334 	spin_lock(&nvram_state_lock);
335 
336 	if ((nvram_open_cnt && (file->f_flags & O_EXCL)) ||
337 	    (nvram_open_mode & NVRAM_EXCL) ||
338 	    ((file->f_mode & FMODE_WRITE) && (nvram_open_mode & NVRAM_WRITE))) {
339 		spin_unlock(&nvram_state_lock);
340 		unlock_kernel();
341 		return -EBUSY;
342 	}
343 
344 	if (file->f_flags & O_EXCL)
345 		nvram_open_mode |= NVRAM_EXCL;
346 	if (file->f_mode & FMODE_WRITE)
347 		nvram_open_mode |= NVRAM_WRITE;
348 	nvram_open_cnt++;
349 
350 	spin_unlock(&nvram_state_lock);
351 	unlock_kernel();
352 
353 	return 0;
354 }
355 
356 static int nvram_release(struct inode *inode, struct file *file)
357 {
358 	spin_lock(&nvram_state_lock);
359 
360 	nvram_open_cnt--;
361 
362 	/* if only one instance is open, clear the EXCL bit */
363 	if (nvram_open_mode & NVRAM_EXCL)
364 		nvram_open_mode &= ~NVRAM_EXCL;
365 	if (file->f_mode & FMODE_WRITE)
366 		nvram_open_mode &= ~NVRAM_WRITE;
367 
368 	spin_unlock(&nvram_state_lock);
369 
370 	return 0;
371 }
372 
373 #ifndef CONFIG_PROC_FS
374 static int nvram_add_proc_fs(void)
375 {
376 	return 0;
377 }
378 
379 #else
380 
381 static int nvram_proc_read(struct seq_file *seq, void *offset)
382 {
383 	unsigned char contents[NVRAM_BYTES];
384 	int i = 0;
385 
386 	spin_lock_irq(&rtc_lock);
387 	for (i = 0; i < NVRAM_BYTES; ++i)
388 		contents[i] = __nvram_read_byte(i);
389 	spin_unlock_irq(&rtc_lock);
390 
391 	mach_proc_infos(contents, seq, offset);
392 
393 	return 0;
394 }
395 
396 static int nvram_proc_open(struct inode *inode, struct file *file)
397 {
398 	return single_open(file, nvram_proc_read, NULL);
399 }
400 
401 static const struct file_operations nvram_proc_fops = {
402 	.owner		= THIS_MODULE,
403 	.open		= nvram_proc_open,
404 	.read		= seq_read,
405 	.llseek		= seq_lseek,
406 	.release	= single_release,
407 };
408 
409 static int nvram_add_proc_fs(void)
410 {
411 	if (!proc_create("driver/nvram", 0, NULL, &nvram_proc_fops))
412 		return -ENOMEM;
413 	return 0;
414 }
415 
416 #endif /* CONFIG_PROC_FS */
417 
418 static const struct file_operations nvram_fops = {
419 	.owner		= THIS_MODULE,
420 	.llseek		= nvram_llseek,
421 	.read		= nvram_read,
422 	.write		= nvram_write,
423 	.ioctl		= nvram_ioctl,
424 	.open		= nvram_open,
425 	.release	= nvram_release,
426 };
427 
428 static struct miscdevice nvram_dev = {
429 	NVRAM_MINOR,
430 	"nvram",
431 	&nvram_fops
432 };
433 
434 static int __init nvram_init(void)
435 {
436 	int ret;
437 
438 	/* First test whether the driver should init at all */
439 	if (!CHECK_DRIVER_INIT())
440 		return -ENODEV;
441 
442 	ret = misc_register(&nvram_dev);
443 	if (ret) {
444 		printk(KERN_ERR "nvram: can't misc_register on minor=%d\n",
445 		    NVRAM_MINOR);
446 		goto out;
447 	}
448 	ret = nvram_add_proc_fs();
449 	if (ret) {
450 		printk(KERN_ERR "nvram: can't create /proc/driver/nvram\n");
451 		goto outmisc;
452 	}
453 	ret = 0;
454 	printk(KERN_INFO "Non-volatile memory driver v" NVRAM_VERSION "\n");
455 out:
456 	return ret;
457 outmisc:
458 	misc_deregister(&nvram_dev);
459 	goto out;
460 }
461 
462 static void __exit nvram_cleanup_module(void)
463 {
464 	remove_proc_entry("driver/nvram", NULL);
465 	misc_deregister(&nvram_dev);
466 }
467 
468 module_init(nvram_init);
469 module_exit(nvram_cleanup_module);
470 
471 /*
472  * Machine specific functions
473  */
474 
475 #if MACH == PC
476 
477 static int pc_check_checksum(void)
478 {
479 	int i;
480 	unsigned short sum = 0;
481 	unsigned short expect;
482 
483 	for (i = PC_CKS_RANGE_START; i <= PC_CKS_RANGE_END; ++i)
484 		sum += __nvram_read_byte(i);
485 	expect = __nvram_read_byte(PC_CKS_LOC)<<8 |
486 	    __nvram_read_byte(PC_CKS_LOC+1);
487 	return (sum & 0xffff) == expect;
488 }
489 
490 static void pc_set_checksum(void)
491 {
492 	int i;
493 	unsigned short sum = 0;
494 
495 	for (i = PC_CKS_RANGE_START; i <= PC_CKS_RANGE_END; ++i)
496 		sum += __nvram_read_byte(i);
497 	__nvram_write_byte(sum >> 8, PC_CKS_LOC);
498 	__nvram_write_byte(sum & 0xff, PC_CKS_LOC + 1);
499 }
500 
501 #ifdef CONFIG_PROC_FS
502 
503 static char *floppy_types[] = {
504 	"none", "5.25'' 360k", "5.25'' 1.2M", "3.5'' 720k", "3.5'' 1.44M",
505 	"3.5'' 2.88M", "3.5'' 2.88M"
506 };
507 
508 static char *gfx_types[] = {
509 	"EGA, VGA, ... (with BIOS)",
510 	"CGA (40 cols)",
511 	"CGA (80 cols)",
512 	"monochrome",
513 };
514 
515 static void pc_proc_infos(unsigned char *nvram, struct seq_file *seq,
516 								void *offset)
517 {
518 	int checksum;
519 	int type;
520 
521 	spin_lock_irq(&rtc_lock);
522 	checksum = __nvram_check_checksum();
523 	spin_unlock_irq(&rtc_lock);
524 
525 	seq_printf(seq, "Checksum status: %svalid\n", checksum ? "" : "not ");
526 
527 	seq_printf(seq, "# floppies     : %d\n",
528 	    (nvram[6] & 1) ? (nvram[6] >> 6) + 1 : 0);
529 	seq_printf(seq, "Floppy 0 type  : ");
530 	type = nvram[2] >> 4;
531 	if (type < ARRAY_SIZE(floppy_types))
532 		seq_printf(seq, "%s\n", floppy_types[type]);
533 	else
534 		seq_printf(seq, "%d (unknown)\n", type);
535 	seq_printf(seq, "Floppy 1 type  : ");
536 	type = nvram[2] & 0x0f;
537 	if (type < ARRAY_SIZE(floppy_types))
538 		seq_printf(seq, "%s\n", floppy_types[type]);
539 	else
540 		seq_printf(seq, "%d (unknown)\n", type);
541 
542 	seq_printf(seq, "HD 0 type      : ");
543 	type = nvram[4] >> 4;
544 	if (type)
545 		seq_printf(seq, "%02x\n", type == 0x0f ? nvram[11] : type);
546 	else
547 		seq_printf(seq, "none\n");
548 
549 	seq_printf(seq, "HD 1 type      : ");
550 	type = nvram[4] & 0x0f;
551 	if (type)
552 		seq_printf(seq, "%02x\n", type == 0x0f ? nvram[12] : type);
553 	else
554 		seq_printf(seq, "none\n");
555 
556 	seq_printf(seq, "HD type 48 data: %d/%d/%d C/H/S, precomp %d, lz %d\n",
557 	    nvram[18] | (nvram[19] << 8),
558 	    nvram[20], nvram[25],
559 	    nvram[21] | (nvram[22] << 8), nvram[23] | (nvram[24] << 8));
560 	seq_printf(seq, "HD type 49 data: %d/%d/%d C/H/S, precomp %d, lz %d\n",
561 	    nvram[39] | (nvram[40] << 8),
562 	    nvram[41], nvram[46],
563 	    nvram[42] | (nvram[43] << 8), nvram[44] | (nvram[45] << 8));
564 
565 	seq_printf(seq, "DOS base memory: %d kB\n", nvram[7] | (nvram[8] << 8));
566 	seq_printf(seq, "Extended memory: %d kB (configured), %d kB (tested)\n",
567 	    nvram[9] | (nvram[10] << 8), nvram[34] | (nvram[35] << 8));
568 
569 	seq_printf(seq, "Gfx adapter    : %s\n",
570 	    gfx_types[(nvram[6] >> 4) & 3]);
571 
572 	seq_printf(seq, "FPU            : %sinstalled\n",
573 	    (nvram[6] & 2) ? "" : "not ");
574 
575 	return;
576 }
577 #endif
578 
579 #endif /* MACH == PC */
580 
581 #if MACH == ATARI
582 
583 static int atari_check_checksum(void)
584 {
585 	int i;
586 	unsigned char sum = 0;
587 
588 	for (i = ATARI_CKS_RANGE_START; i <= ATARI_CKS_RANGE_END; ++i)
589 		sum += __nvram_read_byte(i);
590 	return (__nvram_read_byte(ATARI_CKS_LOC) == (~sum & 0xff)) &&
591 	    (__nvram_read_byte(ATARI_CKS_LOC + 1) == (sum & 0xff));
592 }
593 
594 static void atari_set_checksum(void)
595 {
596 	int i;
597 	unsigned char sum = 0;
598 
599 	for (i = ATARI_CKS_RANGE_START; i <= ATARI_CKS_RANGE_END; ++i)
600 		sum += __nvram_read_byte(i);
601 	__nvram_write_byte(~sum, ATARI_CKS_LOC);
602 	__nvram_write_byte(sum, ATARI_CKS_LOC + 1);
603 }
604 
605 #ifdef CONFIG_PROC_FS
606 
607 static struct {
608 	unsigned char val;
609 	char *name;
610 } boot_prefs[] = {
611 	{ 0x80, "TOS" },
612 	{ 0x40, "ASV" },
613 	{ 0x20, "NetBSD (?)" },
614 	{ 0x10, "Linux" },
615 	{ 0x00, "unspecified" }
616 };
617 
618 static char *languages[] = {
619 	"English (US)",
620 	"German",
621 	"French",
622 	"English (UK)",
623 	"Spanish",
624 	"Italian",
625 	"6 (undefined)",
626 	"Swiss (French)",
627 	"Swiss (German)"
628 };
629 
630 static char *dateformat[] = {
631 	"MM%cDD%cYY",
632 	"DD%cMM%cYY",
633 	"YY%cMM%cDD",
634 	"YY%cDD%cMM",
635 	"4 (undefined)",
636 	"5 (undefined)",
637 	"6 (undefined)",
638 	"7 (undefined)"
639 };
640 
641 static char *colors[] = {
642 	"2", "4", "16", "256", "65536", "??", "??", "??"
643 };
644 
645 static void atari_proc_infos(unsigned char *nvram, struct seq_file *seq,
646 								void *offset)
647 {
648 	int checksum = nvram_check_checksum();
649 	int i;
650 	unsigned vmode;
651 
652 	seq_printf(seq, "Checksum status  : %svalid\n", checksum ? "" : "not ");
653 
654 	seq_printf(seq, "Boot preference  : ");
655 	for (i = ARRAY_SIZE(boot_prefs) - 1; i >= 0; --i) {
656 		if (nvram[1] == boot_prefs[i].val) {
657 			seq_printf(seq, "%s\n", boot_prefs[i].name);
658 			break;
659 		}
660 	}
661 	if (i < 0)
662 		seq_printf(seq, "0x%02x (undefined)\n", nvram[1]);
663 
664 	seq_printf(seq, "SCSI arbitration : %s\n",
665 	    (nvram[16] & 0x80) ? "on" : "off");
666 	seq_printf(seq, "SCSI host ID     : ");
667 	if (nvram[16] & 0x80)
668 		seq_printf(seq, "%d\n", nvram[16] & 7);
669 	else
670 		seq_printf(seq, "n/a\n");
671 
672 	/* the following entries are defined only for the Falcon */
673 	if ((atari_mch_cookie >> 16) != ATARI_MCH_FALCON)
674 		return;
675 
676 	seq_printf(seq, "OS language      : ");
677 	if (nvram[6] < ARRAY_SIZE(languages))
678 		seq_printf(seq, "%s\n", languages[nvram[6]]);
679 	else
680 		seq_printf(seq, "%u (undefined)\n", nvram[6]);
681 	seq_printf(seq, "Keyboard language: ");
682 	if (nvram[7] < ARRAY_SIZE(languages))
683 		seq_printf(seq, "%s\n", languages[nvram[7]]);
684 	else
685 		seq_printf(seq, "%u (undefined)\n", nvram[7]);
686 	seq_printf(seq, "Date format      : ");
687 	seq_printf(seq, dateformat[nvram[8] & 7],
688 	    nvram[9] ? nvram[9] : '/', nvram[9] ? nvram[9] : '/');
689 	seq_printf(seq, ", %dh clock\n", nvram[8] & 16 ? 24 : 12);
690 	seq_printf(seq, "Boot delay       : ");
691 	if (nvram[10] == 0)
692 		seq_printf(seq, "default");
693 	else
694 		seq_printf(seq, "%ds%s\n", nvram[10],
695 		    nvram[10] < 8 ? ", no memory test" : "");
696 
697 	vmode = (nvram[14] << 8) || nvram[15];
698 	seq_printf(seq,
699 	    "Video mode       : %s colors, %d columns, %s %s monitor\n",
700 	    colors[vmode & 7],
701 	    vmode & 8 ? 80 : 40,
702 	    vmode & 16 ? "VGA" : "TV", vmode & 32 ? "PAL" : "NTSC");
703 	seq_printf(seq, "                   %soverscan, compat. mode %s%s\n",
704 	    vmode & 64 ? "" : "no ",
705 	    vmode & 128 ? "on" : "off",
706 	    vmode & 256 ?
707 	    (vmode & 16 ? ", line doubling" : ", half screen") : "");
708 
709 	return;
710 }
711 #endif
712 
713 #endif /* MACH == ATARI */
714 
715 MODULE_LICENSE("GPL");
716 MODULE_ALIAS_MISCDEV(NVRAM_MINOR);
717