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