[MTD] mtdoops: allow MTD selection by name
[linux-2.6.git] / drivers / mtd / mtdoops.c
1 /*
2  * MTD Oops/Panic logger
3  *
4  * Copyright (C) 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/spinlock.h>
33 #include <linux/interrupt.h>
34 #include <linux/mtd/mtd.h>
35
36 #define MTDOOPS_KERNMSG_MAGIC 0x5d005d00
37 #define OOPS_PAGE_SIZE 4096
38
39 static struct mtdoops_context {
40         int mtd_index;
41         struct work_struct work_erase;
42         struct work_struct work_write;
43         struct mtd_info *mtd;
44         int oops_pages;
45         int nextpage;
46         int nextcount;
47         char *name;
48
49         void *oops_buf;
50
51         /* writecount and disabling ready are spin lock protected */
52         spinlock_t writecount_lock;
53         int ready;
54         int writecount;
55 } oops_cxt;
56
57 static void mtdoops_erase_callback(struct erase_info *done)
58 {
59         wait_queue_head_t *wait_q = (wait_queue_head_t *)done->priv;
60         wake_up(wait_q);
61 }
62
63 static int mtdoops_erase_block(struct mtd_info *mtd, int offset)
64 {
65         struct erase_info erase;
66         DECLARE_WAITQUEUE(wait, current);
67         wait_queue_head_t wait_q;
68         int ret;
69
70         init_waitqueue_head(&wait_q);
71         erase.mtd = mtd;
72         erase.callback = mtdoops_erase_callback;
73         erase.addr = offset;
74         erase.len = mtd->erasesize;
75         erase.priv = (u_long)&wait_q;
76
77         set_current_state(TASK_INTERRUPTIBLE);
78         add_wait_queue(&wait_q, &wait);
79
80         ret = mtd->erase(mtd, &erase);
81         if (ret) {
82                 set_current_state(TASK_RUNNING);
83                 remove_wait_queue(&wait_q, &wait);
84                 printk (KERN_WARNING "mtdoops: erase of region [0x%llx, 0x%llx] "
85                                      "on \"%s\" failed\n",
86                         (unsigned long long)erase.addr, (unsigned long long)erase.len, mtd->name);
87                 return ret;
88         }
89
90         schedule();  /* Wait for erase to finish. */
91         remove_wait_queue(&wait_q, &wait);
92
93         return 0;
94 }
95
96 static void mtdoops_inc_counter(struct mtdoops_context *cxt)
97 {
98         struct mtd_info *mtd = cxt->mtd;
99         size_t retlen;
100         u32 count;
101         int ret;
102
103         cxt->nextpage++;
104         if (cxt->nextpage >= cxt->oops_pages)
105                 cxt->nextpage = 0;
106         cxt->nextcount++;
107         if (cxt->nextcount == 0xffffffff)
108                 cxt->nextcount = 0;
109
110         ret = mtd->read(mtd, cxt->nextpage * OOPS_PAGE_SIZE, 4,
111                         &retlen, (u_char *) &count);
112         if ((retlen != 4) || ((ret < 0) && (ret != -EUCLEAN))) {
113                 printk(KERN_ERR "mtdoops: Read failure at %d (%td of 4 read)"
114                                 ", err %d.\n", cxt->nextpage * OOPS_PAGE_SIZE,
115                                 retlen, ret);
116                 schedule_work(&cxt->work_erase);
117                 return;
118         }
119
120         /* See if we need to erase the next block */
121         if (count != 0xffffffff) {
122                 schedule_work(&cxt->work_erase);
123                 return;
124         }
125
126         printk(KERN_DEBUG "mtdoops: Ready %d, %d (no erase)\n",
127                         cxt->nextpage, cxt->nextcount);
128         cxt->ready = 1;
129 }
130
131 /* Scheduled work - when we can't proceed without erasing a block */
132 static void mtdoops_workfunc_erase(struct work_struct *work)
133 {
134         struct mtdoops_context *cxt =
135                         container_of(work, struct mtdoops_context, work_erase);
136         struct mtd_info *mtd = cxt->mtd;
137         int i = 0, j, ret, mod;
138
139         /* We were unregistered */
140         if (!mtd)
141                 return;
142
143         mod = (cxt->nextpage * OOPS_PAGE_SIZE) % mtd->erasesize;
144         if (mod != 0) {
145                 cxt->nextpage = cxt->nextpage + ((mtd->erasesize - mod) / OOPS_PAGE_SIZE);
146                 if (cxt->nextpage >= cxt->oops_pages)
147                         cxt->nextpage = 0;
148         }
149
150         while (mtd->block_isbad) {
151                 ret = mtd->block_isbad(mtd, cxt->nextpage * OOPS_PAGE_SIZE);
152                 if (!ret)
153                         break;
154                 if (ret < 0) {
155                         printk(KERN_ERR "mtdoops: block_isbad failed, aborting.\n");
156                         return;
157                 }
158 badblock:
159                 printk(KERN_WARNING "mtdoops: Bad block at %08x\n",
160                                 cxt->nextpage * OOPS_PAGE_SIZE);
161                 i++;
162                 cxt->nextpage = cxt->nextpage + (mtd->erasesize / OOPS_PAGE_SIZE);
163                 if (cxt->nextpage >= cxt->oops_pages)
164                         cxt->nextpage = 0;
165                 if (i == (cxt->oops_pages / (mtd->erasesize / OOPS_PAGE_SIZE))) {
166                         printk(KERN_ERR "mtdoops: All blocks bad!\n");
167                         return;
168                 }
169         }
170
171         for (j = 0, ret = -1; (j < 3) && (ret < 0); j++)
172                 ret = mtdoops_erase_block(mtd, cxt->nextpage * OOPS_PAGE_SIZE);
173
174         if (ret >= 0) {
175                 printk(KERN_DEBUG "mtdoops: Ready %d, %d \n", cxt->nextpage, cxt->nextcount);
176                 cxt->ready = 1;
177                 return;
178         }
179
180         if (mtd->block_markbad && (ret == -EIO)) {
181                 ret = mtd->block_markbad(mtd, cxt->nextpage * OOPS_PAGE_SIZE);
182                 if (ret < 0) {
183                         printk(KERN_ERR "mtdoops: block_markbad failed, aborting.\n");
184                         return;
185                 }
186         }
187         goto badblock;
188 }
189
190 static void mtdoops_write(struct mtdoops_context *cxt, int panic)
191 {
192         struct mtd_info *mtd = cxt->mtd;
193         size_t retlen;
194         int ret;
195
196         if (cxt->writecount < OOPS_PAGE_SIZE)
197                 memset(cxt->oops_buf + cxt->writecount, 0xff,
198                                         OOPS_PAGE_SIZE - cxt->writecount);
199
200         if (panic)
201                 ret = mtd->panic_write(mtd, cxt->nextpage * OOPS_PAGE_SIZE,
202                                         OOPS_PAGE_SIZE, &retlen, cxt->oops_buf);
203         else
204                 ret = mtd->write(mtd, cxt->nextpage * OOPS_PAGE_SIZE,
205                                         OOPS_PAGE_SIZE, &retlen, cxt->oops_buf);
206
207         cxt->writecount = 0;
208
209         if ((retlen != OOPS_PAGE_SIZE) || (ret < 0))
210                 printk(KERN_ERR "mtdoops: Write failure at %d (%td of %d written), err %d.\n",
211                         cxt->nextpage * OOPS_PAGE_SIZE, retlen, OOPS_PAGE_SIZE, ret);
212
213         mtdoops_inc_counter(cxt);
214 }
215
216
217 static void mtdoops_workfunc_write(struct work_struct *work)
218 {
219         struct mtdoops_context *cxt =
220                         container_of(work, struct mtdoops_context, work_write);
221
222         mtdoops_write(cxt, 0);
223 }                                       
224
225 static void find_next_position(struct mtdoops_context *cxt)
226 {
227         struct mtd_info *mtd = cxt->mtd;
228         int ret, page, maxpos = 0;
229         u32 count[2], maxcount = 0xffffffff;
230         size_t retlen;
231
232         for (page = 0; page < cxt->oops_pages; page++) {
233                 ret = mtd->read(mtd, page * OOPS_PAGE_SIZE, 8, &retlen, (u_char *) &count[0]);
234                 if ((retlen != 8) || ((ret < 0) && (ret != -EUCLEAN))) {
235                         printk(KERN_ERR "mtdoops: Read failure at %d (%td of 8 read)"
236                                 ", err %d.\n", page * OOPS_PAGE_SIZE, retlen, ret);
237                         continue;
238                 }
239
240                 if (count[1] != MTDOOPS_KERNMSG_MAGIC)
241                         continue;
242                 if (count[0] == 0xffffffff)
243                         continue;
244                 if (maxcount == 0xffffffff) {
245                         maxcount = count[0];
246                         maxpos = page;
247                 } else if ((count[0] < 0x40000000) && (maxcount > 0xc0000000)) {
248                         maxcount = count[0];
249                         maxpos = page;
250                 } else if ((count[0] > maxcount) && (count[0] < 0xc0000000)) {
251                         maxcount = count[0];
252                         maxpos = page;
253                 } else if ((count[0] > maxcount) && (count[0] > 0xc0000000)
254                                         && (maxcount > 0x80000000)) {
255                         maxcount = count[0];
256                         maxpos = page;
257                 }
258         }
259         if (maxcount == 0xffffffff) {
260                 cxt->nextpage = 0;
261                 cxt->nextcount = 1;
262                 schedule_work(&cxt->work_erase);
263                 return;
264         }
265
266         cxt->nextpage = maxpos;
267         cxt->nextcount = maxcount;
268
269         mtdoops_inc_counter(cxt);
270 }
271
272
273 static void mtdoops_notify_add(struct mtd_info *mtd)
274 {
275         struct mtdoops_context *cxt = &oops_cxt;
276
277         if (cxt->name && !strcmp(mtd->name, cxt->name))
278                 cxt->mtd_index = mtd->index;
279
280         if ((mtd->index != cxt->mtd_index) || cxt->mtd_index < 0)
281                 return;
282
283         if (mtd->size < (mtd->erasesize * 2)) {
284                 printk(KERN_ERR "MTD partition %d not big enough for mtdoops\n",
285                                 mtd->index);
286                 return;
287         }
288
289         if (mtd->erasesize < OOPS_PAGE_SIZE) {
290                 printk(KERN_ERR "Eraseblock size of MTD partition %d too small\n",
291                                 mtd->index);
292                 return;
293         }
294
295         cxt->mtd = mtd;
296         if (mtd->size > INT_MAX)
297                 cxt->oops_pages = INT_MAX / OOPS_PAGE_SIZE;
298         else
299                 cxt->oops_pages = (int)mtd->size / OOPS_PAGE_SIZE;
300
301         find_next_position(cxt);
302
303         printk(KERN_INFO "mtdoops: Attached to MTD device %d\n", mtd->index);
304 }
305
306 static void mtdoops_notify_remove(struct mtd_info *mtd)
307 {
308         struct mtdoops_context *cxt = &oops_cxt;
309
310         if ((mtd->index != cxt->mtd_index) || cxt->mtd_index < 0)
311                 return;
312
313         cxt->mtd = NULL;
314         flush_scheduled_work();
315 }
316
317 static void mtdoops_console_sync(void)
318 {
319         struct mtdoops_context *cxt = &oops_cxt;
320         struct mtd_info *mtd = cxt->mtd;
321         unsigned long flags;
322
323         if (!cxt->ready || !mtd || cxt->writecount == 0)
324                 return;
325
326         /* 
327          *  Once ready is 0 and we've held the lock no further writes to the 
328          *  buffer will happen
329          */
330         spin_lock_irqsave(&cxt->writecount_lock, flags);
331         if (!cxt->ready) {
332                 spin_unlock_irqrestore(&cxt->writecount_lock, flags);
333                 return;
334         }
335         cxt->ready = 0;
336         spin_unlock_irqrestore(&cxt->writecount_lock, flags);
337
338         if (mtd->panic_write && in_interrupt())
339                 /* Interrupt context, we're going to panic so try and log */
340                 mtdoops_write(cxt, 1);
341         else
342                 schedule_work(&cxt->work_write);
343 }
344
345 static void
346 mtdoops_console_write(struct console *co, const char *s, unsigned int count)
347 {
348         struct mtdoops_context *cxt = co->data;
349         struct mtd_info *mtd = cxt->mtd;
350         unsigned long flags;
351
352         if (!oops_in_progress) {
353                 mtdoops_console_sync();
354                 return;
355         }
356
357         if (!cxt->ready || !mtd)
358                 return;
359
360         /* Locking on writecount ensures sequential writes to the buffer */
361         spin_lock_irqsave(&cxt->writecount_lock, flags);
362
363         /* Check ready status didn't change whilst waiting for the lock */
364         if (!cxt->ready)
365                 return;
366
367         if (cxt->writecount == 0) {
368                 u32 *stamp = cxt->oops_buf;
369                 *stamp++ = cxt->nextcount;
370                 *stamp = MTDOOPS_KERNMSG_MAGIC;
371                 cxt->writecount = 8;
372         }
373
374         if ((count + cxt->writecount) > OOPS_PAGE_SIZE)
375                 count = OOPS_PAGE_SIZE - cxt->writecount;
376
377         memcpy(cxt->oops_buf + cxt->writecount, s, count);
378         cxt->writecount += count;
379
380         spin_unlock_irqrestore(&cxt->writecount_lock, flags);
381
382         if (cxt->writecount == OOPS_PAGE_SIZE)
383                 mtdoops_console_sync();
384 }
385
386 static int __init mtdoops_console_setup(struct console *co, char *options)
387 {
388         struct mtdoops_context *cxt = co->data;
389
390         if (cxt->mtd_index != -1 || cxt->name)
391                 return -EBUSY;
392         if (options) {
393                 cxt->name = kstrdup(options, GFP_KERNEL);
394                 return 0;
395         }
396         if (co->index == -1)
397                 return -EINVAL;
398
399         cxt->mtd_index = co->index;
400         return 0;
401 }
402
403 static struct mtd_notifier mtdoops_notifier = {
404         .add    = mtdoops_notify_add,
405         .remove = mtdoops_notify_remove,
406 };
407
408 static struct console mtdoops_console = {
409         .name           = "ttyMTD",
410         .write          = mtdoops_console_write,
411         .setup          = mtdoops_console_setup,
412         .unblank        = mtdoops_console_sync,
413         .index          = -1,
414         .data           = &oops_cxt,
415 };
416
417 static int __init mtdoops_console_init(void)
418 {
419         struct mtdoops_context *cxt = &oops_cxt;
420
421         cxt->mtd_index = -1;
422         cxt->oops_buf = vmalloc(OOPS_PAGE_SIZE);
423
424         if (!cxt->oops_buf) {
425                 printk(KERN_ERR "Failed to allocate mtdoops buffer workspace\n");
426                 return -ENOMEM;
427         }
428
429         INIT_WORK(&cxt->work_erase, mtdoops_workfunc_erase);
430         INIT_WORK(&cxt->work_write, mtdoops_workfunc_write);
431
432         register_console(&mtdoops_console);
433         register_mtd_user(&mtdoops_notifier);
434         return 0;
435 }
436
437 static void __exit mtdoops_console_exit(void)
438 {
439         struct mtdoops_context *cxt = &oops_cxt;
440
441         unregister_mtd_user(&mtdoops_notifier);
442         unregister_console(&mtdoops_console);
443         kfree(cxt->name);
444         vfree(cxt->oops_buf);
445 }
446
447
448 subsys_initcall(mtdoops_console_init);
449 module_exit(mtdoops_console_exit);
450
451 MODULE_LICENSE("GPL");
452 MODULE_AUTHOR("Richard Purdie <rpurdie@openedhand.com>");
453 MODULE_DESCRIPTION("MTD Oops/Panic console logger/driver");