e3e40f4403235540dc5ad5f6e3efd35aa981f647
[linux-2.6.git] / drivers / mtd / mtdoops.c
1 /*
2  * MTD Oops/Panic logger
3  *
4  * Copyright © 2007 Nokia Corporation. All rights reserved.
5  *
6  * Author: Richard Purdie <rpurdie@openedhand.com>
7  *
8  * This program is free software; you can redistribute it and/or
9  * modify it under the terms of the GNU General Public License
10  * version 2 as published by the Free Software Foundation.
11  *
12  * This program is distributed in the hope that it will be useful, but
13  * WITHOUT ANY WARRANTY; without even the implied warranty of
14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
15  * General Public License for more details.
16  *
17  * You should have received a copy of the GNU General Public License
18  * along with this program; if not, write to the Free Software
19  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
20  * 02110-1301 USA
21  *
22  */
23
24 #include <linux/kernel.h>
25 #include <linux/module.h>
26 #include <linux/console.h>
27 #include <linux/vmalloc.h>
28 #include <linux/workqueue.h>
29 #include <linux/sched.h>
30 #include <linux/wait.h>
31 #include <linux/delay.h>
32 #include <linux/interrupt.h>
33 #include <linux/mtd/mtd.h>
34 #include <linux/kmsg_dump.h>
35
36 /* Maximum MTD partition size */
37 #define MTDOOPS_MAX_MTD_SIZE (8 * 1024 * 1024)
38
39 #define MTDOOPS_KERNMSG_MAGIC 0x5d005d00
40 #define MTDOOPS_HEADER_SIZE   8
41
42 static unsigned long record_size = 4096;
43 module_param(record_size, ulong, 0400);
44 MODULE_PARM_DESC(record_size,
45                 "record size for MTD OOPS pages in bytes (default 4096)");
46
47 static char mtddev[80];
48 module_param_string(mtddev, mtddev, 80, 0400);
49 MODULE_PARM_DESC(mtddev,
50                 "name or index number of the MTD device to use");
51
52 static int dump_oops = 1;
53 module_param(dump_oops, int, 0600);
54 MODULE_PARM_DESC(dump_oops,
55                 "set to 1 to dump oopses, 0 to only dump panics (default 1)");
56
57 static struct mtdoops_context {
58         struct kmsg_dumper dump;
59
60         int mtd_index;
61         struct work_struct work_erase;
62         struct work_struct work_write;
63         struct mtd_info *mtd;
64         int oops_pages;
65         int nextpage;
66         int nextcount;
67         unsigned long *oops_page_used;
68
69         void *oops_buf;
70 } oops_cxt;
71
72 static void mark_page_used(struct mtdoops_context *cxt, int page)
73 {
74         set_bit(page, cxt->oops_page_used);
75 }
76
77 static void mark_page_unused(struct mtdoops_context *cxt, int page)
78 {
79         clear_bit(page, cxt->oops_page_used);
80 }
81
82 static int page_is_used(struct mtdoops_context *cxt, int page)
83 {
84         return test_bit(page, cxt->oops_page_used);
85 }
86
87 static void mtdoops_erase_callback(struct erase_info *done)
88 {
89         wait_queue_head_t *wait_q = (wait_queue_head_t *)done->priv;
90         wake_up(wait_q);
91 }
92
93 static int mtdoops_erase_block(struct mtdoops_context *cxt, int offset)
94 {
95         struct mtd_info *mtd = cxt->mtd;
96         u32 start_page_offset = mtd_div_by_eb(offset, mtd) * mtd->erasesize;
97         u32 start_page = start_page_offset / record_size;
98         u32 erase_pages = mtd->erasesize / record_size;
99         struct erase_info erase;
100         DECLARE_WAITQUEUE(wait, current);
101         wait_queue_head_t wait_q;
102         int ret;
103         int page;
104
105         init_waitqueue_head(&wait_q);
106         erase.mtd = mtd;
107         erase.callback = mtdoops_erase_callback;
108         erase.addr = offset;
109         erase.len = mtd->erasesize;
110         erase.priv = (u_long)&wait_q;
111
112         set_current_state(TASK_INTERRUPTIBLE);
113         add_wait_queue(&wait_q, &wait);
114
115         ret = mtd->erase(mtd, &erase);
116         if (ret) {
117                 set_current_state(TASK_RUNNING);
118                 remove_wait_queue(&wait_q, &wait);
119                 printk(KERN_WARNING "mtdoops: erase of region [0x%llx, 0x%llx] on \"%s\" failed\n",
120                        (unsigned long long)erase.addr,
121                        (unsigned long long)erase.len, mtddev);
122                 return ret;
123         }
124
125         schedule();  /* Wait for erase to finish. */
126         remove_wait_queue(&wait_q, &wait);
127
128         /* Mark pages as unused */
129         for (page = start_page; page < start_page + erase_pages; page++)
130                 mark_page_unused(cxt, page);
131
132         return 0;
133 }
134
135 static void mtdoops_inc_counter(struct mtdoops_context *cxt)
136 {
137         cxt->nextpage++;
138         if (cxt->nextpage >= cxt->oops_pages)
139                 cxt->nextpage = 0;
140         cxt->nextcount++;
141         if (cxt->nextcount == 0xffffffff)
142                 cxt->nextcount = 0;
143
144         if (page_is_used(cxt, cxt->nextpage)) {
145                 schedule_work(&cxt->work_erase);
146                 return;
147         }
148
149         printk(KERN_DEBUG "mtdoops: ready %d, %d (no erase)\n",
150                cxt->nextpage, cxt->nextcount);
151 }
152
153 /* Scheduled work - when we can't proceed without erasing a block */
154 static void mtdoops_workfunc_erase(struct work_struct *work)
155 {
156         struct mtdoops_context *cxt =
157                         container_of(work, struct mtdoops_context, work_erase);
158         struct mtd_info *mtd = cxt->mtd;
159         int i = 0, j, ret, mod;
160
161         /* We were unregistered */
162         if (!mtd)
163                 return;
164
165         mod = (cxt->nextpage * record_size) % mtd->erasesize;
166         if (mod != 0) {
167                 cxt->nextpage = cxt->nextpage + ((mtd->erasesize - mod) / record_size);
168                 if (cxt->nextpage >= cxt->oops_pages)
169                         cxt->nextpage = 0;
170         }
171
172         while (mtd->block_isbad) {
173                 ret = mtd->block_isbad(mtd, cxt->nextpage * record_size);
174                 if (!ret)
175                         break;
176                 if (ret < 0) {
177                         printk(KERN_ERR "mtdoops: block_isbad failed, aborting\n");
178                         return;
179                 }
180 badblock:
181                 printk(KERN_WARNING "mtdoops: bad block at %08lx\n",
182                        cxt->nextpage * record_size);
183                 i++;
184                 cxt->nextpage = cxt->nextpage + (mtd->erasesize / record_size);
185                 if (cxt->nextpage >= cxt->oops_pages)
186                         cxt->nextpage = 0;
187                 if (i == cxt->oops_pages / (mtd->erasesize / record_size)) {
188                         printk(KERN_ERR "mtdoops: all blocks bad!\n");
189                         return;
190                 }
191         }
192
193         for (j = 0, ret = -1; (j < 3) && (ret < 0); j++)
194                 ret = mtdoops_erase_block(cxt, cxt->nextpage * record_size);
195
196         if (ret >= 0) {
197                 printk(KERN_DEBUG "mtdoops: ready %d, %d\n",
198                        cxt->nextpage, cxt->nextcount);
199                 return;
200         }
201
202         if (mtd->block_markbad && ret == -EIO) {
203                 ret = mtd->block_markbad(mtd, cxt->nextpage * record_size);
204                 if (ret < 0) {
205                         printk(KERN_ERR "mtdoops: block_markbad failed, aborting\n");
206                         return;
207                 }
208         }
209         goto badblock;
210 }
211
212 static void mtdoops_write(struct mtdoops_context *cxt, int panic)
213 {
214         struct mtd_info *mtd = cxt->mtd;
215         size_t retlen;
216         u32 *hdr;
217         int ret;
218
219         /* Add mtdoops header to the buffer */
220         hdr = cxt->oops_buf;
221         hdr[0] = cxt->nextcount;
222         hdr[1] = MTDOOPS_KERNMSG_MAGIC;
223
224         if (panic)
225                 ret = mtd->panic_write(mtd, cxt->nextpage * record_size,
226                                         record_size, &retlen, cxt->oops_buf);
227         else
228                 ret = mtd->write(mtd, cxt->nextpage * record_size,
229                                         record_size, &retlen, cxt->oops_buf);
230
231         if (retlen != record_size || ret < 0)
232                 printk(KERN_ERR "mtdoops: write failure at %ld (%td of %ld written), error %d\n",
233                        cxt->nextpage * record_size, retlen, record_size, ret);
234         mark_page_used(cxt, cxt->nextpage);
235         memset(cxt->oops_buf, 0xff, record_size);
236
237         mtdoops_inc_counter(cxt);
238 }
239
240 static void mtdoops_workfunc_write(struct work_struct *work)
241 {
242         struct mtdoops_context *cxt =
243                         container_of(work, struct mtdoops_context, work_write);
244
245         mtdoops_write(cxt, 0);
246 }
247
248 static void find_next_position(struct mtdoops_context *cxt)
249 {
250         struct mtd_info *mtd = cxt->mtd;
251         int ret, page, maxpos = 0;
252         u32 count[2], maxcount = 0xffffffff;
253         size_t retlen;
254
255         for (page = 0; page < cxt->oops_pages; page++) {
256                 /* Assume the page is used */
257                 mark_page_used(cxt, page);
258                 ret = mtd->read(mtd, page * record_size, MTDOOPS_HEADER_SIZE,
259                                 &retlen, (u_char *) &count[0]);
260                 if (retlen != MTDOOPS_HEADER_SIZE ||
261                                 (ret < 0 && ret != -EUCLEAN)) {
262                         printk(KERN_ERR "mtdoops: read failure at %ld (%td of %d read), err %d\n",
263                                page * record_size, retlen,
264                                MTDOOPS_HEADER_SIZE, ret);
265                         continue;
266                 }
267
268                 if (count[0] == 0xffffffff && count[1] == 0xffffffff)
269                         mark_page_unused(cxt, page);
270                 if (count[0] == 0xffffffff)
271                         continue;
272                 if (maxcount == 0xffffffff) {
273                         maxcount = count[0];
274                         maxpos = page;
275                 } else if (count[0] < 0x40000000 && maxcount > 0xc0000000) {
276                         maxcount = count[0];
277                         maxpos = page;
278                 } else if (count[0] > maxcount && count[0] < 0xc0000000) {
279                         maxcount = count[0];
280                         maxpos = page;
281                 } else if (count[0] > maxcount && count[0] > 0xc0000000
282                                         && maxcount > 0x80000000) {
283                         maxcount = count[0];
284                         maxpos = page;
285                 }
286         }
287         if (maxcount == 0xffffffff) {
288                 cxt->nextpage = 0;
289                 cxt->nextcount = 1;
290                 schedule_work(&cxt->work_erase);
291                 return;
292         }
293
294         cxt->nextpage = maxpos;
295         cxt->nextcount = maxcount;
296
297         mtdoops_inc_counter(cxt);
298 }
299
300 static void mtdoops_do_dump(struct kmsg_dumper *dumper,
301                 enum kmsg_dump_reason reason, const char *s1, unsigned long l1,
302                 const char *s2, unsigned long l2)
303 {
304         struct mtdoops_context *cxt = container_of(dumper,
305                         struct mtdoops_context, dump);
306         unsigned long s1_start, s2_start;
307         unsigned long l1_cpy, l2_cpy;
308         char *dst;
309
310         if (reason != KMSG_DUMP_OOPS &&
311             reason != KMSG_DUMP_PANIC &&
312             reason != KMSG_DUMP_KEXEC)
313                 return;
314
315         /* Only dump oopses if dump_oops is set */
316         if (reason == KMSG_DUMP_OOPS && !dump_oops)
317                 return;
318
319         dst = cxt->oops_buf + MTDOOPS_HEADER_SIZE; /* Skip the header */
320         l2_cpy = min(l2, record_size - MTDOOPS_HEADER_SIZE);
321         l1_cpy = min(l1, record_size - MTDOOPS_HEADER_SIZE - l2_cpy);
322
323         s2_start = l2 - l2_cpy;
324         s1_start = l1 - l1_cpy;
325
326         memcpy(dst, s1 + s1_start, l1_cpy);
327         memcpy(dst + l1_cpy, s2 + s2_start, l2_cpy);
328
329         /* Panics must be written immediately */
330         if (reason != KMSG_DUMP_OOPS) {
331                 if (!cxt->mtd->panic_write)
332                         printk(KERN_ERR "mtdoops: Cannot write from panic without panic_write\n");
333                 else
334                         mtdoops_write(cxt, 1);
335                 return;
336         }
337
338         /* For other cases, schedule work to write it "nicely" */
339         schedule_work(&cxt->work_write);
340 }
341
342 static void mtdoops_notify_add(struct mtd_info *mtd)
343 {
344         struct mtdoops_context *cxt = &oops_cxt;
345         u64 mtdoops_pages = div_u64(mtd->size, record_size);
346         int err;
347
348         if (!strcmp(mtd->name, mtddev))
349                 cxt->mtd_index = mtd->index;
350
351         if (mtd->index != cxt->mtd_index || cxt->mtd_index < 0)
352                 return;
353
354         if (mtd->size < mtd->erasesize * 2) {
355                 printk(KERN_ERR "mtdoops: MTD partition %d not big enough for mtdoops\n",
356                        mtd->index);
357                 return;
358         }
359         if (mtd->erasesize < record_size) {
360                 printk(KERN_ERR "mtdoops: eraseblock size of MTD partition %d too small\n",
361                        mtd->index);
362                 return;
363         }
364         if (mtd->size > MTDOOPS_MAX_MTD_SIZE) {
365                 printk(KERN_ERR "mtdoops: mtd%d is too large (limit is %d MiB)\n",
366                        mtd->index, MTDOOPS_MAX_MTD_SIZE / 1024 / 1024);
367                 return;
368         }
369
370         /* oops_page_used is a bit field */
371         cxt->oops_page_used = vmalloc(DIV_ROUND_UP(mtdoops_pages,
372                         BITS_PER_LONG));
373         if (!cxt->oops_page_used) {
374                 printk(KERN_ERR "mtdoops: could not allocate page array\n");
375                 return;
376         }
377
378         cxt->dump.dump = mtdoops_do_dump;
379         err = kmsg_dump_register(&cxt->dump);
380         if (err) {
381                 printk(KERN_ERR "mtdoops: registering kmsg dumper failed, error %d\n", err);
382                 vfree(cxt->oops_page_used);
383                 cxt->oops_page_used = NULL;
384                 return;
385         }
386
387         cxt->mtd = mtd;
388         cxt->oops_pages = (int)mtd->size / record_size;
389         find_next_position(cxt);
390         printk(KERN_INFO "mtdoops: Attached to MTD device %d\n", mtd->index);
391 }
392
393 static void mtdoops_notify_remove(struct mtd_info *mtd)
394 {
395         struct mtdoops_context *cxt = &oops_cxt;
396
397         if (mtd->index != cxt->mtd_index || cxt->mtd_index < 0)
398                 return;
399
400         if (kmsg_dump_unregister(&cxt->dump) < 0)
401                 printk(KERN_WARNING "mtdoops: could not unregister kmsg_dumper\n");
402
403         cxt->mtd = NULL;
404         flush_work_sync(&cxt->work_erase);
405         flush_work_sync(&cxt->work_write);
406 }
407
408
409 static struct mtd_notifier mtdoops_notifier = {
410         .add    = mtdoops_notify_add,
411         .remove = mtdoops_notify_remove,
412 };
413
414 static int __init mtdoops_init(void)
415 {
416         struct mtdoops_context *cxt = &oops_cxt;
417         int mtd_index;
418         char *endp;
419
420         if (strlen(mtddev) == 0) {
421                 printk(KERN_ERR "mtdoops: mtd device (mtddev=name/number) must be supplied\n");
422                 return -EINVAL;
423         }
424         if ((record_size & 4095) != 0) {
425                 printk(KERN_ERR "mtdoops: record_size must be a multiple of 4096\n");
426                 return -EINVAL;
427         }
428         if (record_size < 4096) {
429                 printk(KERN_ERR "mtdoops: record_size must be over 4096 bytes\n");
430                 return -EINVAL;
431         }
432
433         /* Setup the MTD device to use */
434         cxt->mtd_index = -1;
435         mtd_index = simple_strtoul(mtddev, &endp, 0);
436         if (*endp == '\0')
437                 cxt->mtd_index = mtd_index;
438
439         cxt->oops_buf = vmalloc(record_size);
440         if (!cxt->oops_buf) {
441                 printk(KERN_ERR "mtdoops: failed to allocate buffer workspace\n");
442                 return -ENOMEM;
443         }
444         memset(cxt->oops_buf, 0xff, record_size);
445
446         INIT_WORK(&cxt->work_erase, mtdoops_workfunc_erase);
447         INIT_WORK(&cxt->work_write, mtdoops_workfunc_write);
448
449         register_mtd_user(&mtdoops_notifier);
450         return 0;
451 }
452
453 static void __exit mtdoops_exit(void)
454 {
455         struct mtdoops_context *cxt = &oops_cxt;
456
457         unregister_mtd_user(&mtdoops_notifier);
458         vfree(cxt->oops_buf);
459         vfree(cxt->oops_page_used);
460 }
461
462
463 module_init(mtdoops_init);
464 module_exit(mtdoops_exit);
465
466 MODULE_LICENSE("GPL");
467 MODULE_AUTHOR("Richard Purdie <rpurdie@openedhand.com>");
468 MODULE_DESCRIPTION("MTD Oops/Panic console logger/driver");