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