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 *
7 * This driver allows you to access the contents of the non-volatile memory in
8 * the mc146818rtc.h real-time clock. This chip is built into all PCs and into
9 * many Atari machines. In the former it's called "CMOS-RAM", in the latter
10 * "NVRAM" (NV stands for non-volatile).
11 *
12 * The data are supplied as a (seekable) character device, /dev/nvram. The
13 * size of this file is 50, the number of freely available bytes in the memory
14 * (i.e., not used by the RTC itself).
15 *
16 * Checksums over the NVRAM contents are managed by this driver. In case of a
17 * bad checksum, reads and writes return -EIO. The checksum can be initialized
18 * to a sane state either by ioctl(NVRAM_INIT) (clear whole NVRAM) or
19 * ioctl(NVRAM_SETCKS) (doesn't change contents, just makes checksum valid
20 * again; use with care!)
21 *
22 * This file also provides some functions for other parts of the kernel that
23 * want to access the NVRAM: nvram_{read,write,check_checksum,set_checksum}.
24 * Obviously this can be used only if this driver is always configured into
25 * the kernel and is not a module. Since the functions are used by some Atari
26 * drivers, this is the case on the Atari.
27 *
28 *
29 * 1.1 Cesar Barros: SMP locking fixes
30 * added changelog
31 */
32
33 #define NVRAM_VERSION "1.1"
34
35 #include <linux/module.h>
36 #include <linux/config.h>
37 #include <linux/sched.h>
38 #include <linux/smp_lock.h>
39
40 #define PC 1
41 #define ATARI 2
42
43 /* select machine configuration */
44 #if defined(CONFIG_ATARI)
45 #define MACH ATARI
46 #elif defined(__i386__) || defined(__arm__) /* and others?? */
47 #define MACH PC
48 #else
49 #error Cannot build nvram driver for this machine configuration.
50 #endif
51
52 #if MACH == PC
53
54 /* RTC in a PC */
55 #define CHECK_DRIVER_INIT() 1
56
57 /* On PCs, the checksum is built only over bytes 2..31 */
58 #define PC_CKS_RANGE_START 2
59 #define PC_CKS_RANGE_END 31
60 #define PC_CKS_LOC 32
61
62 #define mach_check_checksum pc_check_checksum
63 #define mach_set_checksum pc_set_checksum
64 #define mach_proc_infos pc_proc_infos
65
66 #endif
67
68 #if MACH == ATARI
69
70 /* Special parameters for RTC in Atari machines */
71 #include <asm/atarihw.h>
72 #include <asm/atariints.h>
73 #define RTC_PORT(x) (TT_RTC_BAS + 2*(x))
74 #define CHECK_DRIVER_INIT() (MACH_IS_ATARI && ATARIHW_PRESENT(TT_CLK))
75
76 /* On Ataris, the checksum is over all bytes except the checksum bytes
77 * themselves; these are at the very end */
78 #define ATARI_CKS_RANGE_START 0
79 #define ATARI_CKS_RANGE_END 47
80 #define ATARI_CKS_LOC 48
81
82 #define mach_check_checksum atari_check_checksum
83 #define mach_set_checksum atari_set_checksum
84 #define mach_proc_infos atari_proc_infos
85
86 #endif
87
88 /* Note that *all* calls to CMOS_READ and CMOS_WRITE must be done with
89 * rtc_lock held. Due to the index-port/data-port design of the RTC, we
90 * don't want two different things trying to get to it at once. (e.g. the
91 * periodic 11 min sync from time.c vs. this driver.)
92 */
93
94 #include <linux/types.h>
95 #include <linux/errno.h>
96 #include <linux/miscdevice.h>
97 #include <linux/malloc.h>
98 #include <linux/ioport.h>
99 #include <linux/fcntl.h>
100 #include <linux/mc146818rtc.h>
101 #include <linux/nvram.h>
102 #include <linux/init.h>
103 #include <linux/proc_fs.h>
104 #include <linux/spinlock.h>
105
106 #include <asm/io.h>
107 #include <asm/uaccess.h>
108 #include <asm/system.h>
109
110 static int nvram_open_cnt; /* #times opened */
111 static int nvram_open_mode; /* special open modes */
112 #define NVRAM_WRITE 1 /* opened for writing (exclusive) */
113 #define NVRAM_EXCL 2 /* opened with O_EXCL */
114
115 #define RTC_FIRST_BYTE 14 /* RTC register number of first NVRAM byte */
116 #define NVRAM_BYTES 50 /* number of NVRAM bytes */
117
118
119 static int mach_check_checksum( void );
120 static void mach_set_checksum( void );
121 #ifdef CONFIG_PROC_FS
122 static int mach_proc_infos( unsigned char *contents, char *buffer, int *len,
123 off_t *begin, off_t offset, int size );
124 #endif
125
126
127 /*
128 * These are the internal NVRAM access functions, which do NOT disable
129 * interrupts and do not check the checksum. Both tasks are left to higher
130 * level function, so they need to be done only once per syscall.
131 */
132
133 static __inline__ unsigned char nvram_read_int( int i )
134 {
135 return( CMOS_READ( RTC_FIRST_BYTE+i ) );
136 }
137
138 static __inline__ void nvram_write_int( unsigned char c, int i )
139 {
140 CMOS_WRITE( c, RTC_FIRST_BYTE+i );
141 }
142
143 static __inline__ int nvram_check_checksum_int( void )
144 {
145 return( mach_check_checksum() );
146 }
147
148 static __inline__ void nvram_set_checksum_int( void )
149 {
150 mach_set_checksum();
151 }
152
153 #if MACH == ATARI
154
155 /*
156 * These non-internal functions are provided to be called by other parts of
157 * the kernel. It's up to the caller to ensure correct checksum before reading
158 * or after writing (needs to be done only once).
159 *
160 * They're only built if CONFIG_ATARI is defined, because Atari drivers use
161 * them. For other configurations (PC), the rest of the kernel can't rely on
162 * them being present (this driver may not be configured at all, or as a
163 * module), so they access config information themselves.
164 */
165
166 unsigned char nvram_read_byte( int i )
167 {
168 unsigned long flags;
169 unsigned char c;
170
171 spin_lock_irqsave (&rtc_lock, flags);
172 c = nvram_read_int( i );
173 spin_unlock_irqrestore (&rtc_lock, flags);
174 return( c );
175 }
176
177 /* This races nicely with trying to read with checksum checking (nvram_read) */
178 void nvram_write_byte( unsigned char c, int i )
179 {
180 unsigned long flags;
181
182 spin_lock_irqsave (&rtc_lock, flags);
183 nvram_write_int( c, i );
184 spin_unlock_irqrestore (&rtc_lock, flags);
185 }
186
187 int nvram_check_checksum( void )
188 {
189 unsigned long flags;
190 int rv;
191
192 spin_lock_irqsave (&rtc_lock, flags);
193 rv = nvram_check_checksum_int();
194 spin_unlock_irqrestore (&rtc_lock, flags);
195 return( rv );
196 }
197
198 void nvram_set_checksum( void )
199 {
200 unsigned long flags;
201
202 spin_lock_irqsave (&rtc_lock, flags);
203 nvram_set_checksum_int();
204 spin_unlock_irqrestore (&rtc_lock, flags);
205 }
206
207 #endif /* MACH == ATARI */
208
209
210 /*
211 * The are the file operation function for user access to /dev/nvram
212 */
213
214 static long long 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 return( (offset >= 0) ? (file->f_pos = offset) : -EINVAL );
228 }
229
230 static ssize_t nvram_read(struct file * file,
231 char * buf, size_t count, loff_t *ppos )
232 {
233 char contents [NVRAM_BYTES];
234 unsigned i = *ppos;
235 char *tmp;
236
237 spin_lock_irq (&rtc_lock);
238
239 if (!nvram_check_checksum_int())
240 goto checksum_err;
241
242 for (tmp = contents; count-- > 0 && i < NVRAM_BYTES; ++i, ++tmp)
243 *tmp = nvram_read_int(i);
244
245 spin_unlock_irq (&rtc_lock);
246
247 if (copy_to_user (buf, contents, tmp - contents))
248 return -EFAULT;
249
250 *ppos = i;
251
252 return (tmp - contents);
253
254 checksum_err:
255 spin_unlock_irq (&rtc_lock);
256 return -EIO;
257 }
258
259 static ssize_t nvram_write(struct file * file,
260 const char * buf, size_t count, loff_t *ppos )
261 {
262 char contents [NVRAM_BYTES];
263 unsigned i = *ppos;
264 char * tmp;
265
266 if (copy_from_user (contents, buf, (NVRAM_BYTES - i) < count ?
267 (NVRAM_BYTES - i) : count))
268 return -EFAULT;
269
270 spin_lock_irq (&rtc_lock);
271
272 if (!nvram_check_checksum_int())
273 goto checksum_err;
274
275 for (tmp = contents; count-- > 0 && i < NVRAM_BYTES; ++i, ++tmp)
276 nvram_write_int (*tmp, i);
277
278 nvram_set_checksum_int();
279
280 spin_unlock_irq (&rtc_lock);
281
282 *ppos = i;
283
284 return (tmp - contents);
285
286 checksum_err:
287 spin_unlock_irq (&rtc_lock);
288 return -EIO;
289 }
290
291 static int nvram_ioctl( struct inode *inode, struct file *file,
292 unsigned int cmd, unsigned long arg )
293 {
294 int i;
295
296 switch( cmd ) {
297
298 case NVRAM_INIT: /* initialize NVRAM contents and checksum */
299 if (!capable(CAP_SYS_ADMIN))
300 return( -EACCES );
301
302 spin_lock_irq (&rtc_lock);
303
304 for( i = 0; i < NVRAM_BYTES; ++i )
305 nvram_write_int( 0, i );
306 nvram_set_checksum_int();
307
308 spin_unlock_irq (&rtc_lock);
309 return( 0 );
310
311 case NVRAM_SETCKS: /* just set checksum, contents unchanged
312 * (maybe useful after checksum garbaged
313 * somehow...) */
314 if (!capable(CAP_SYS_ADMIN))
315 return( -EACCES );
316
317 spin_lock_irq (&rtc_lock);
318 nvram_set_checksum_int();
319 spin_unlock_irq (&rtc_lock);
320 return( 0 );
321
322 default:
323 return( -EINVAL );
324 }
325 }
326
327 static int nvram_open( struct inode *inode, struct file *file )
328 {
329 if ((nvram_open_cnt && (file->f_flags & O_EXCL)) ||
330 (nvram_open_mode & NVRAM_EXCL) ||
331 ((file->f_mode & 2) && (nvram_open_mode & NVRAM_WRITE)))
332 return( -EBUSY );
333
334 if (file->f_flags & O_EXCL)
335 nvram_open_mode |= NVRAM_EXCL;
336 if (file->f_mode & 2)
337 nvram_open_mode |= NVRAM_WRITE;
338 nvram_open_cnt++;
339 return( 0 );
340 }
341
342 static int nvram_release( struct inode *inode, struct file *file )
343 {
344 lock_kernel();
345 nvram_open_cnt--;
346 if (file->f_flags & O_EXCL)
347 nvram_open_mode &= ~NVRAM_EXCL;
348 if (file->f_mode & 2)
349 nvram_open_mode &= ~NVRAM_WRITE;
350 unlock_kernel();
351
352 return( 0 );
353 }
354
355
356 #ifndef CONFIG_PROC_FS
357 static int nvram_read_proc( char *buffer, char **start, off_t offset,
358 int size, int *eof, void *data) { return 0; }
359 #else
360
361 static int nvram_read_proc( char *buffer, char **start, off_t offset,
362 int size, int *eof, void *data )
363 {
364 unsigned char contents[NVRAM_BYTES];
365 int i, len = 0;
366 off_t begin = 0;
367
368 spin_lock_irq (&rtc_lock);
369 for( i = 0; i < NVRAM_BYTES; ++i )
370 contents[i] = nvram_read_int( i );
371 spin_unlock_irq (&rtc_lock);
372
373 *eof = mach_proc_infos( contents, buffer, &len, &begin, offset, size );
374
375 if (offset >= begin + len)
376 return( 0 );
377 *start = buffer + (offset - begin);
378 return( size < begin + len - offset ? size : begin + len - offset );
379
380 }
381
382 /* This macro frees the machine specific function from bounds checking and
383 * this like that... */
384 #define PRINT_PROC(fmt,args...) \
385 do { \
386 *len += sprintf( buffer+*len, fmt, ##args ); \
387 if (*begin + *len > offset + size) \
388 return( 0 ); \
389 if (*begin + *len < offset) { \
390 *begin += *len; \
391 *len = 0; \
392 } \
393 } while(0)
394
395 #endif /* CONFIG_PROC_FS */
396
397 static struct file_operations nvram_fops = {
398 owner: THIS_MODULE,
399 llseek: nvram_llseek,
400 read: nvram_read,
401 write: nvram_write,
402 ioctl: nvram_ioctl,
403 open: nvram_open,
404 release: nvram_release,
405 };
406
407 static struct miscdevice nvram_dev = {
408 NVRAM_MINOR,
409 "nvram",
410 &nvram_fops
411 };
412
413
414 static int __init nvram_init(void)
415 {
416 int ret;
417
418 /* First test whether the driver should init at all */
419 if (!CHECK_DRIVER_INIT())
420 return( -ENXIO );
421
422 ret = misc_register( &nvram_dev );
423 if (ret) {
424 printk(KERN_ERR "nvram: can't misc_register on minor=%d\n", NVRAM_MINOR);
425 goto out;
426 }
427 if (!create_proc_read_entry("driver/nvram",0,0,nvram_read_proc,NULL)) {
428 printk(KERN_ERR "nvram: can't create /proc/driver/nvram\n");
429 ret = -ENOMEM;
430 goto outmisc;
431 }
432 ret = 0;
433 printk(KERN_INFO "Non-volatile memory driver v" NVRAM_VERSION "\n");
434 out:
435 return( ret );
436 outmisc:
437 misc_deregister( &nvram_dev );
438 goto out;
439 }
440
441 static void __exit nvram_cleanup_module (void)
442 {
443 remove_proc_entry( "driver/nvram", 0 );
444 misc_deregister( &nvram_dev );
445 }
446
447 module_init(nvram_init);
448 module_exit(nvram_cleanup_module);
449
450
451 /*
452 * Machine specific functions
453 */
454
455
456 #if MACH == PC
457
458 static int pc_check_checksum( void )
459 {
460 int i;
461 unsigned short sum = 0;
462
463 for( i = PC_CKS_RANGE_START; i <= PC_CKS_RANGE_END; ++i )
464 sum += nvram_read_int( i );
465 return( (sum & 0xffff) ==
466 ((nvram_read_int(PC_CKS_LOC) << 8) |
467 nvram_read_int(PC_CKS_LOC+1)) );
468 }
469
470 static void pc_set_checksum( void )
471 {
472 int i;
473 unsigned short sum = 0;
474
475 for( i = PC_CKS_RANGE_START; i <= PC_CKS_RANGE_END; ++i )
476 sum += nvram_read_int( i );
477 nvram_write_int( sum >> 8, PC_CKS_LOC );
478 nvram_write_int( sum & 0xff, PC_CKS_LOC+1 );
479 }
480
481 #ifdef CONFIG_PROC_FS
482
483 static char *floppy_types[] = {
484 "none", "5.25'' 360k", "5.25'' 1.2M", "3.5'' 720k", "3.5'' 1.44M", "3.5'' 2.88M"
485 };
486
487 static char *gfx_types[] = {
488 "EGA, VGA, ... (with BIOS)",
489 "CGA (40 cols)",
490 "CGA (80 cols)",
491 "monochrome",
492 };
493
494 static int pc_proc_infos( unsigned char *nvram, char *buffer, int *len,
495 off_t *begin, off_t offset, int size )
496 {
497 int checksum;
498 int type;
499
500 spin_lock_irq (&rtc_lock);
501 checksum = nvram_check_checksum_int();
502 spin_unlock_irq (&rtc_lock);
503
504 PRINT_PROC( "Checksum status: %svalid\n", checksum ? "" : "not " );
505
506 PRINT_PROC( "# floppies : %d\n",
507 (nvram[6] & 1) ? (nvram[6] >> 6) + 1 : 0 );
508 PRINT_PROC( "Floppy 0 type : " );
509 type = nvram[2] >> 4;
510 if (type < sizeof(floppy_types)/sizeof(*floppy_types))
511 PRINT_PROC( "%s\n", floppy_types[type] );
512 else
513 PRINT_PROC( "%d (unknown)\n", type );
514 PRINT_PROC( "Floppy 1 type : " );
515 type = nvram[2] & 0x0f;
516 if (type < sizeof(floppy_types)/sizeof(*floppy_types))
517 PRINT_PROC( "%s\n", floppy_types[type] );
518 else
519 PRINT_PROC( "%d (unknown)\n", type );
520
521 PRINT_PROC( "HD 0 type : " );
522 type = nvram[4] >> 4;
523 if (type)
524 PRINT_PROC( "%02x\n", type == 0x0f ? nvram[11] : type );
525 else
526 PRINT_PROC( "none\n" );
527
528 PRINT_PROC( "HD 1 type : " );
529 type = nvram[4] & 0x0f;
530 if (type)
531 PRINT_PROC( "%02x\n", type == 0x0f ? nvram[12] : type );
532 else
533 PRINT_PROC( "none\n" );
534
535 PRINT_PROC( "HD type 48 data: %d/%d/%d C/H/S, precomp %d, lz %d\n",
536 nvram[18] | (nvram[19] << 8),
537 nvram[20], nvram[25],
538 nvram[21] | (nvram[22] << 8),
539 nvram[23] | (nvram[24] << 8) );
540 PRINT_PROC( "HD type 49 data: %d/%d/%d C/H/S, precomp %d, lz %d\n",
541 nvram[39] | (nvram[40] << 8),
542 nvram[41], nvram[46],
543 nvram[42] | (nvram[43] << 8),
544 nvram[44] | (nvram[45] << 8) );
545
546 PRINT_PROC( "DOS base memory: %d kB\n", nvram[7] | (nvram[8] << 8) );
547 PRINT_PROC( "Extended memory: %d kB (configured), %d kB (tested)\n",
548 nvram[9] | (nvram[10] << 8),
549 nvram[34] | (nvram[35] << 8) );
550
551 PRINT_PROC( "Gfx adapter : %s\n", gfx_types[ (nvram[6] >> 4)&3 ] );
552
553 PRINT_PROC( "FPU : %sinstalled\n",
554 (nvram[6] & 2) ? "" : "not " );
555
556 return( 1 );
557 }
558 #endif
559
560 #endif /* MACH == PC */
561
562 #if MACH == ATARI
563
564 static int atari_check_checksum( void )
565 {
566 int i;
567 unsigned char sum = 0;
568
569 for( i = ATARI_CKS_RANGE_START; i <= ATARI_CKS_RANGE_END; ++i )
570 sum += nvram_read_int( i );
571 return( nvram_read_int( ATARI_CKS_LOC ) == (~sum & 0xff) &&
572 nvram_read_int( ATARI_CKS_LOC+1 ) == (sum & 0xff) );
573 }
574
575 static void atari_set_checksum( void )
576 {
577 int i;
578 unsigned char sum = 0;
579
580 for( i = ATARI_CKS_RANGE_START; i <= ATARI_CKS_RANGE_END; ++i )
581 sum += nvram_read_int( i );
582 nvram_write_int( ~sum, ATARI_CKS_LOC );
583 nvram_write_int( sum, ATARI_CKS_LOC+1 );
584 }
585
586 #ifdef CONFIG_PROC_FS
587
588 static struct {
589 unsigned char val;
590 char *name;
591 } boot_prefs[] = {
592 { 0x80, "TOS" },
593 { 0x40, "ASV" },
594 { 0x20, "NetBSD (?)" },
595 { 0x10, "Linux" },
596 { 0x00, "unspecified" }
597 };
598
599 static char *languages[] = {
600 "English (US)",
601 "German",
602 "French",
603 "English (UK)",
604 "Spanish",
605 "Italian",
606 "6 (undefined)",
607 "Swiss (French)",
608 "Swiss (German)"
609 };
610
611 static char *dateformat[] = {
612 "MM%cDD%cYY",
613 "DD%cMM%cYY",
614 "YY%cMM%cDD",
615 "YY%cDD%cMM",
616 "4 (undefined)",
617 "5 (undefined)",
618 "6 (undefined)",
619 "7 (undefined)"
620 };
621
622 static char *colors[] = {
623 "2", "4", "16", "256", "65536", "??", "??", "??"
624 };
625
626 #define fieldsize(a) (sizeof(a)/sizeof(*a))
627
628 static int atari_proc_infos( unsigned char *nvram, char *buffer, int *len,
629 off_t *begin, off_t offset, int size )
630 {
631 int checksum = nvram_check_checksum();
632 int i;
633 unsigned vmode;
634
635 PRINT_PROC( "Checksum status : %svalid\n", checksum ? "" : "not " );
636
637 PRINT_PROC( "Boot preference : " );
638 for( i = fieldsize(boot_prefs)-1; i >= 0; --i ) {
639 if (nvram[1] == boot_prefs[i].val) {
640 PRINT_PROC( "%s\n", boot_prefs[i].name );
641 break;
642 }
643 }
644 if (i < 0)
645 PRINT_PROC( "0x%02x (undefined)\n", nvram[1] );
646
647 PRINT_PROC( "SCSI arbitration : %s\n", (nvram[16] & 0x80) ? "on" : "off" );
648 PRINT_PROC( "SCSI host ID : " );
649 if (nvram[16] & 0x80)
650 PRINT_PROC( "%d\n", nvram[16] & 7 );
651 else
652 PRINT_PROC( "n/a\n" );
653
654 /* the following entries are defined only for the Falcon */
655 if ((atari_mch_cookie >> 16) != ATARI_MCH_FALCON)
656 return 1;
657
658 PRINT_PROC( "OS language : " );
659 if (nvram[6] < fieldsize(languages))
660 PRINT_PROC( "%s\n", languages[nvram[6]] );
661 else
662 PRINT_PROC( "%u (undefined)\n", nvram[6] );
663 PRINT_PROC( "Keyboard language: " );
664 if (nvram[7] < fieldsize(languages))
665 PRINT_PROC( "%s\n", languages[nvram[7]] );
666 else
667 PRINT_PROC( "%u (undefined)\n", nvram[7] );
668 PRINT_PROC( "Date format : " );
669 PRINT_PROC( dateformat[nvram[8]&7],
670 nvram[9] ? nvram[9] : '/', nvram[9] ? nvram[9] : '/' );
671 PRINT_PROC( ", %dh clock\n", nvram[8] & 16 ? 24 : 12 );
672 PRINT_PROC( "Boot delay : " );
673 if (nvram[10] == 0)
674 PRINT_PROC( "default" );
675 else
676 PRINT_PROC( "%ds%s\n", nvram[10],
677 nvram[10] < 8 ? ", no memory test" : "" );
678
679 vmode = (nvram[14] << 8) || nvram[15];
680 PRINT_PROC( "Video mode : %s colors, %d columns, %s %s monitor\n",
681 colors[vmode & 7],
682 vmode & 8 ? 80 : 40,
683 vmode & 16 ? "VGA" : "TV",
684 vmode & 32 ? "PAL" : "NTSC" );
685 PRINT_PROC( " %soverscan, compat. mode %s%s\n",
686 vmode & 64 ? "" : "no ",
687 vmode & 128 ? "on" : "off",
688 vmode & 256 ?
689 (vmode & 16 ? ", line doubling" : ", half screen") : "" );
690
691 return( 1 );
692 }
693 #endif
694
695 #endif /* MACH == ATARI */
696
697 /*
698 * Local variables:
699 * c-indent-level: 4
700 * tab-width: 4
701 * End:
702 */
703
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