readahead: combine file_ra_state.prev_index/prev_offset into prev_pos
[linux-2.6.git] / drivers / char / nwflash.c
1 /*
2  * Flash memory interface rev.5 driver for the Intel
3  * Flash chips used on the NetWinder.
4  *
5  * 20/08/2000   RMK     use __ioremap to map flash into virtual memory
6  *                      make a few more places use "volatile"
7  * 22/05/2001   RMK     - Lock read against write
8  *                      - merge printk level changes (with mods) from Alan Cox.
9  *                      - use *ppos as the file position, not file->f_pos.
10  *                      - fix check for out of range pos and r/w size
11  *
12  * Please note that we are tampering with the only flash chip in the
13  * machine, which contains the bootup code.  We therefore have the
14  * power to convert these machines into doorstops...
15  */
16
17 #include <linux/module.h>
18 #include <linux/types.h>
19 #include <linux/fs.h>
20 #include <linux/errno.h>
21 #include <linux/mm.h>
22 #include <linux/delay.h>
23 #include <linux/proc_fs.h>
24 #include <linux/miscdevice.h>
25 #include <linux/spinlock.h>
26 #include <linux/rwsem.h>
27 #include <linux/init.h>
28 #include <linux/smp_lock.h>
29 #include <linux/mutex.h>
30
31 #include <asm/hardware/dec21285.h>
32 #include <asm/io.h>
33 #include <asm/leds.h>
34 #include <asm/mach-types.h>
35 #include <asm/system.h>
36 #include <asm/uaccess.h>
37
38 /*****************************************************************************/
39 #include <asm/nwflash.h>
40
41 #define NWFLASH_VERSION "6.4"
42
43 static void kick_open(void);
44 static int get_flash_id(void);
45 static int erase_block(int nBlock);
46 static int write_block(unsigned long p, const char __user *buf, int count);
47
48 #define KFLASH_SIZE     1024*1024       //1 Meg
49 #define KFLASH_SIZE4    4*1024*1024     //4 Meg
50 #define KFLASH_ID       0x89A6          //Intel flash
51 #define KFLASH_ID4      0xB0D4          //Intel flash 4Meg
52
53 static int flashdebug;          //if set - we will display progress msgs
54
55 static int gbWriteEnable;
56 static int gbWriteBase64Enable;
57 static volatile unsigned char *FLASH_BASE;
58 static int gbFlashSize = KFLASH_SIZE;
59 static DEFINE_MUTEX(nwflash_mutex);
60
61 extern spinlock_t gpio_lock;
62
63 static int get_flash_id(void)
64 {
65         volatile unsigned int c1, c2;
66
67         /*
68          * try to get flash chip ID
69          */
70         kick_open();
71         c2 = inb(0x80);
72         *(volatile unsigned char *) (FLASH_BASE + 0x8000) = 0x90;
73         udelay(15);
74         c1 = *(volatile unsigned char *) FLASH_BASE;
75         c2 = inb(0x80);
76
77         /*
78          * on 4 Meg flash the second byte is actually at offset 2...
79          */
80         if (c1 == 0xB0)
81                 c2 = *(volatile unsigned char *) (FLASH_BASE + 2);
82         else
83                 c2 = *(volatile unsigned char *) (FLASH_BASE + 1);
84
85         c2 += (c1 << 8);
86
87         /*
88          * set it back to read mode
89          */
90         *(volatile unsigned char *) (FLASH_BASE + 0x8000) = 0xFF;
91
92         if (c2 == KFLASH_ID4)
93                 gbFlashSize = KFLASH_SIZE4;
94
95         return c2;
96 }
97
98 static int flash_ioctl(struct inode *inodep, struct file *filep, unsigned int cmd, unsigned long arg)
99 {
100         switch (cmd) {
101         case CMD_WRITE_DISABLE:
102                 gbWriteBase64Enable = 0;
103                 gbWriteEnable = 0;
104                 break;
105
106         case CMD_WRITE_ENABLE:
107                 gbWriteEnable = 1;
108                 break;
109
110         case CMD_WRITE_BASE64K_ENABLE:
111                 gbWriteBase64Enable = 1;
112                 break;
113
114         default:
115                 gbWriteBase64Enable = 0;
116                 gbWriteEnable = 0;
117                 return -EINVAL;
118         }
119         return 0;
120 }
121
122 static ssize_t flash_read(struct file *file, char __user *buf, size_t size,
123                           loff_t *ppos)
124 {
125         unsigned long p = *ppos;
126         unsigned int count = size;
127         int ret = 0;
128
129         if (flashdebug)
130                 printk(KERN_DEBUG "flash_read: flash_read: offset=0x%lX, "
131                        "buffer=%p, count=0x%X.\n", p, buf, count);
132
133         if (count)
134                 ret = -ENXIO;
135
136         if (p < gbFlashSize) {
137                 if (count > gbFlashSize - p)
138                         count = gbFlashSize - p;
139
140                 /*
141                  * We now lock against reads and writes. --rmk
142                  */
143                 if (mutex_lock_interruptible(&nwflash_mutex))
144                         return -ERESTARTSYS;
145
146                 ret = copy_to_user(buf, (void *)(FLASH_BASE + p), count);
147                 if (ret == 0) {
148                         ret = count;
149                         *ppos += count;
150                 } else
151                         ret = -EFAULT;
152                 mutex_unlock(&nwflash_mutex);
153         }
154         return ret;
155 }
156
157 static ssize_t flash_write(struct file *file, const char __user *buf,
158                            size_t size, loff_t * ppos)
159 {
160         unsigned long p = *ppos;
161         unsigned int count = size;
162         int written;
163         int nBlock, temp, rc;
164         int i, j;
165
166         if (flashdebug)
167                 printk("flash_write: offset=0x%lX, buffer=0x%p, count=0x%X.\n",
168                        p, buf, count);
169
170         if (!gbWriteEnable)
171                 return -EINVAL;
172
173         if (p < 64 * 1024 && (!gbWriteBase64Enable))
174                 return -EINVAL;
175
176         /*
177          * check for out of range pos or count
178          */
179         if (p >= gbFlashSize)
180                 return count ? -ENXIO : 0;
181
182         if (count > gbFlashSize - p)
183                 count = gbFlashSize - p;
184                         
185         if (!access_ok(VERIFY_READ, buf, count))
186                 return -EFAULT;
187
188         /*
189          * We now lock against reads and writes. --rmk
190          */
191         if (mutex_lock_interruptible(&nwflash_mutex))
192                 return -ERESTARTSYS;
193
194         written = 0;
195
196         leds_event(led_claim);
197         leds_event(led_green_on);
198
199         nBlock = (int) p >> 16; //block # of 64K bytes
200
201         /*
202          * # of 64K blocks to erase and write
203          */
204         temp = ((int) (p + count) >> 16) - nBlock + 1;
205
206         /*
207          * write ends at exactly 64k boundary?
208          */
209         if (((int) (p + count) & 0xFFFF) == 0)
210                 temp -= 1;
211
212         if (flashdebug)
213                 printk(KERN_DEBUG "flash_write: writing %d block(s) "
214                         "starting at %d.\n", temp, nBlock);
215
216         for (; temp; temp--, nBlock++) {
217                 if (flashdebug)
218                         printk(KERN_DEBUG "flash_write: erasing block %d.\n", nBlock);
219
220                 /*
221                  * first we have to erase the block(s), where we will write...
222                  */
223                 i = 0;
224                 j = 0;
225           RetryBlock:
226                 do {
227                         rc = erase_block(nBlock);
228                         i++;
229                 } while (rc && i < 10);
230
231                 if (rc) {
232                         printk(KERN_ERR "flash_write: erase error %x\n", rc);
233                         break;
234                 }
235                 if (flashdebug)
236                         printk(KERN_DEBUG "flash_write: writing offset %lX, "
237                                "from buf %p, bytes left %X.\n", p, buf,
238                                count - written);
239
240                 /*
241                  * write_block will limit write to space left in this block
242                  */
243                 rc = write_block(p, buf, count - written);
244                 j++;
245
246                 /*
247                  * if somehow write verify failed? Can't happen??
248                  */
249                 if (!rc) {
250                         /*
251                          * retry up to 10 times
252                          */
253                         if (j < 10)
254                                 goto RetryBlock;
255                         else
256                                 /*
257                                  * else quit with error...
258                                  */
259                                 rc = -1;
260
261                 }
262                 if (rc < 0) {
263                         printk(KERN_ERR "flash_write: write error %X\n", rc);
264                         break;
265                 }
266                 p += rc;
267                 buf += rc;
268                 written += rc;
269                 *ppos += rc;
270
271                 if (flashdebug)
272                         printk(KERN_DEBUG "flash_write: written 0x%X bytes OK.\n", written);
273         }
274
275         /*
276          * restore reg on exit
277          */
278         leds_event(led_release);
279
280         mutex_unlock(&nwflash_mutex);
281
282         return written;
283 }
284
285
286 /*
287  * The memory devices use the full 32/64 bits of the offset, and so we cannot
288  * check against negative addresses: they are ok. The return value is weird,
289  * though, in that case (0).
290  *
291  * also note that seeking relative to the "end of file" isn't supported:
292  * it has no meaning, so it returns -EINVAL.
293  */
294 static loff_t flash_llseek(struct file *file, loff_t offset, int orig)
295 {
296         loff_t ret;
297
298         lock_kernel();
299         if (flashdebug)
300                 printk(KERN_DEBUG "flash_llseek: offset=0x%X, orig=0x%X.\n",
301                        (unsigned int) offset, orig);
302
303         switch (orig) {
304         case 0:
305                 if (offset < 0) {
306                         ret = -EINVAL;
307                         break;
308                 }
309
310                 if ((unsigned int) offset > gbFlashSize) {
311                         ret = -EINVAL;
312                         break;
313                 }
314
315                 file->f_pos = (unsigned int) offset;
316                 ret = file->f_pos;
317                 break;
318         case 1:
319                 if ((file->f_pos + offset) > gbFlashSize) {
320                         ret = -EINVAL;
321                         break;
322                 }
323                 if ((file->f_pos + offset) < 0) {
324                         ret = -EINVAL;
325                         break;
326                 }
327                 file->f_pos += offset;
328                 ret = file->f_pos;
329                 break;
330         default:
331                 ret = -EINVAL;
332         }
333         unlock_kernel();
334         return ret;
335 }
336
337
338 /*
339  * assume that main Write routine did the parameter checking...
340  * so just go ahead and erase, what requested!
341  */
342
343 static int erase_block(int nBlock)
344 {
345         volatile unsigned int c1;
346         volatile unsigned char *pWritePtr;
347         unsigned long timeout;
348         int temp, temp1;
349
350         /*
351          * orange LED == erase
352          */
353         leds_event(led_amber_on);
354
355         /*
356          * reset footbridge to the correct offset 0 (...0..3)
357          */
358         *CSR_ROMWRITEREG = 0;
359
360         /*
361          * dummy ROM read
362          */
363         c1 = *(volatile unsigned char *) (FLASH_BASE + 0x8000);
364
365         kick_open();
366         /*
367          * reset status if old errors
368          */
369         *(volatile unsigned char *) (FLASH_BASE + 0x8000) = 0x50;
370
371         /*
372          * erase a block...
373          * aim at the middle of a current block...
374          */
375         pWritePtr = (unsigned char *) ((unsigned int) (FLASH_BASE + 0x8000 + (nBlock << 16)));
376         /*
377          * dummy read
378          */
379         c1 = *pWritePtr;
380
381         kick_open();
382         /*
383          * erase
384          */
385         *(volatile unsigned char *) pWritePtr = 0x20;
386
387         /*
388          * confirm
389          */
390         *(volatile unsigned char *) pWritePtr = 0xD0;
391
392         /*
393          * wait 10 ms
394          */
395         msleep(10);
396
397         /*
398          * wait while erasing in process (up to 10 sec)
399          */
400         timeout = jiffies + 10 * HZ;
401         c1 = 0;
402         while (!(c1 & 0x80) && time_before(jiffies, timeout)) {
403                 msleep(10);
404                 /*
405                  * read any address
406                  */
407                 c1 = *(volatile unsigned char *) (pWritePtr);
408                 //              printk("Flash_erase: status=%X.\n",c1);
409         }
410
411         /*
412          * set flash for normal read access
413          */
414         kick_open();
415 //      *(volatile unsigned char*)(FLASH_BASE+0x8000) = 0xFF;
416         *(volatile unsigned char *) pWritePtr = 0xFF;   //back to normal operation
417
418         /*
419          * check if erase errors were reported
420          */
421         if (c1 & 0x20) {
422                 printk(KERN_ERR "flash_erase: err at %p\n", pWritePtr);
423
424                 /*
425                  * reset error
426                  */
427                 *(volatile unsigned char *) (FLASH_BASE + 0x8000) = 0x50;
428                 return -2;
429         }
430
431         /*
432          * just to make sure - verify if erased OK...
433          */
434         msleep(10);
435
436         pWritePtr = (unsigned char *) ((unsigned int) (FLASH_BASE + (nBlock << 16)));
437
438         for (temp = 0; temp < 16 * 1024; temp++, pWritePtr += 4) {
439                 if ((temp1 = *(volatile unsigned int *) pWritePtr) != 0xFFFFFFFF) {
440                         printk(KERN_ERR "flash_erase: verify err at %p = %X\n",
441                                pWritePtr, temp1);
442                         return -1;
443                 }
444         }
445
446         return 0;
447
448 }
449
450 /*
451  * write_block will limit number of bytes written to the space in this block
452  */
453 static int write_block(unsigned long p, const char __user *buf, int count)
454 {
455         volatile unsigned int c1;
456         volatile unsigned int c2;
457         unsigned char *pWritePtr;
458         unsigned int uAddress;
459         unsigned int offset;
460         unsigned long timeout;
461         unsigned long timeout1;
462
463         /*
464          * red LED == write
465          */
466         leds_event(led_amber_off);
467         leds_event(led_red_on);
468
469         pWritePtr = (unsigned char *) ((unsigned int) (FLASH_BASE + p));
470
471         /*
472          * check if write will end in this block....
473          */
474         offset = p & 0xFFFF;
475
476         if (offset + count > 0x10000)
477                 count = 0x10000 - offset;
478
479         /*
480          * wait up to 30 sec for this block
481          */
482         timeout = jiffies + 30 * HZ;
483
484         for (offset = 0; offset < count; offset++, pWritePtr++) {
485                 uAddress = (unsigned int) pWritePtr;
486                 uAddress &= 0xFFFFFFFC;
487                 if (__get_user(c2, buf + offset))
488                         return -EFAULT;
489
490           WriteRetry:
491                 /*
492                  * dummy read
493                  */
494                 c1 = *(volatile unsigned char *) (FLASH_BASE + 0x8000);
495
496                 /*
497                  * kick open the write gate
498                  */
499                 kick_open();
500
501                 /*
502                  * program footbridge to the correct offset...0..3
503                  */
504                 *CSR_ROMWRITEREG = (unsigned int) pWritePtr & 3;
505
506                 /*
507                  * write cmd
508                  */
509                 *(volatile unsigned char *) (uAddress) = 0x40;
510
511                 /*
512                  * data to write
513                  */
514                 *(volatile unsigned char *) (uAddress) = c2;
515
516                 /*
517                  * get status
518                  */
519                 *(volatile unsigned char *) (FLASH_BASE + 0x10000) = 0x70;
520
521                 c1 = 0;
522
523                 /*
524                  * wait up to 1 sec for this byte
525                  */
526                 timeout1 = jiffies + 1 * HZ;
527
528                 /*
529                  * while not ready...
530                  */
531                 while (!(c1 & 0x80) && time_before(jiffies, timeout1))
532                         c1 = *(volatile unsigned char *) (FLASH_BASE + 0x8000);
533
534                 /*
535                  * if timeout getting status
536                  */
537                 if (time_after_eq(jiffies, timeout1)) {
538                         kick_open();
539                         /*
540                          * reset err
541                          */
542                         *(volatile unsigned char *) (FLASH_BASE + 0x8000) = 0x50;
543
544                         goto WriteRetry;
545                 }
546                 /*
547                  * switch on read access, as a default flash operation mode
548                  */
549                 kick_open();
550                 /*
551                  * read access
552                  */
553                 *(volatile unsigned char *) (FLASH_BASE + 0x8000) = 0xFF;
554
555                 /*
556                  * if hardware reports an error writing, and not timeout - 
557                  * reset the chip and retry
558                  */
559                 if (c1 & 0x10) {
560                         kick_open();
561                         /*
562                          * reset err
563                          */
564                         *(volatile unsigned char *) (FLASH_BASE + 0x8000) = 0x50;
565
566                         /*
567                          * before timeout?
568                          */
569                         if (time_before(jiffies, timeout)) {
570                                 if (flashdebug)
571                                         printk(KERN_DEBUG "write_block: Retrying write at 0x%X)n",
572                                                pWritePtr - FLASH_BASE);
573
574                                 /*
575                                  * no LED == waiting
576                                  */
577                                 leds_event(led_amber_off);
578                                 /*
579                                  * wait couple ms
580                                  */
581                                 msleep(10);
582                                 /*
583                                  * red LED == write
584                                  */
585                                 leds_event(led_red_on);
586
587                                 goto WriteRetry;
588                         } else {
589                                 printk(KERN_ERR "write_block: timeout at 0x%X\n",
590                                        pWritePtr - FLASH_BASE);
591                                 /*
592                                  * return error -2
593                                  */
594                                 return -2;
595
596                         }
597                 }
598         }
599
600         /*
601          * green LED == read/verify
602          */
603         leds_event(led_amber_off);
604         leds_event(led_green_on);
605
606         msleep(10);
607
608         pWritePtr = (unsigned char *) ((unsigned int) (FLASH_BASE + p));
609
610         for (offset = 0; offset < count; offset++) {
611                 char c, c1;
612                 if (__get_user(c, buf))
613                         return -EFAULT;
614                 buf++;
615                 if ((c1 = *pWritePtr++) != c) {
616                         printk(KERN_ERR "write_block: verify error at 0x%X (%02X!=%02X)\n",
617                                pWritePtr - FLASH_BASE, c1, c);
618                         return 0;
619                 }
620         }
621
622         return count;
623 }
624
625
626 static void kick_open(void)
627 {
628         unsigned long flags;
629
630         /*
631          * we want to write a bit pattern XXX1 to Xilinx to enable
632          * the write gate, which will be open for about the next 2ms.
633          */
634         spin_lock_irqsave(&gpio_lock, flags);
635         cpld_modify(1, 1);
636         spin_unlock_irqrestore(&gpio_lock, flags);
637
638         /*
639          * let the ISA bus to catch on...
640          */
641         udelay(25);
642 }
643
644 static const struct file_operations flash_fops =
645 {
646         .owner          = THIS_MODULE,
647         .llseek         = flash_llseek,
648         .read           = flash_read,
649         .write          = flash_write,
650         .ioctl          = flash_ioctl,
651 };
652
653 static struct miscdevice flash_miscdev =
654 {
655         FLASH_MINOR,
656         "nwflash",
657         &flash_fops
658 };
659
660 static int __init nwflash_init(void)
661 {
662         int ret = -ENODEV;
663
664         if (machine_is_netwinder()) {
665                 int id;
666
667                 FLASH_BASE = ioremap(DC21285_FLASH, KFLASH_SIZE4);
668                 if (!FLASH_BASE)
669                         goto out;
670
671                 id = get_flash_id();
672                 if ((id != KFLASH_ID) && (id != KFLASH_ID4)) {
673                         ret = -ENXIO;
674                         iounmap((void *)FLASH_BASE);
675                         printk("Flash: incorrect ID 0x%04X.\n", id);
676                         goto out;
677                 }
678
679                 printk("Flash ROM driver v.%s, flash device ID 0x%04X, size %d Mb.\n",
680                        NWFLASH_VERSION, id, gbFlashSize / (1024 * 1024));
681
682                 ret = misc_register(&flash_miscdev);
683                 if (ret < 0) {
684                         iounmap((void *)FLASH_BASE);
685                 }
686         }
687 out:
688         return ret;
689 }
690
691 static void __exit nwflash_exit(void)
692 {
693         misc_deregister(&flash_miscdev);
694         iounmap((void *)FLASH_BASE);
695 }
696
697 MODULE_LICENSE("GPL");
698
699 module_param(flashdebug, bool, 0644);
700
701 module_init(nwflash_init);
702 module_exit(nwflash_exit);