[MTD] mtdoops: Perform write operations in a workqueue
[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/mtd/mtd.h>
32
33 #define OOPS_PAGE_SIZE 4096
34
35 struct mtdoops_context {
36         int mtd_index;
37         struct work_struct work_erase;
38         struct work_struct work_write;
39         struct mtd_info *mtd;
40         int oops_pages;
41         int nextpage;
42         int nextcount;
43
44         void *oops_buf;
45         int ready;
46         int writecount;
47 } oops_cxt;
48
49 static void mtdoops_erase_callback(struct erase_info *done)
50 {
51         wait_queue_head_t *wait_q = (wait_queue_head_t *)done->priv;
52         wake_up(wait_q);
53 }
54
55 static int mtdoops_erase_block(struct mtd_info *mtd, int offset)
56 {
57         struct erase_info erase;
58         DECLARE_WAITQUEUE(wait, current);
59         wait_queue_head_t wait_q;
60         int ret;
61
62         init_waitqueue_head(&wait_q);
63         erase.mtd = mtd;
64         erase.callback = mtdoops_erase_callback;
65         erase.addr = offset;
66         if (mtd->erasesize < OOPS_PAGE_SIZE)
67                 erase.len = OOPS_PAGE_SIZE;
68         else
69                 erase.len = mtd->erasesize;
70         erase.priv = (u_long)&wait_q;
71
72         set_current_state(TASK_INTERRUPTIBLE);
73         add_wait_queue(&wait_q, &wait);
74
75         ret = mtd->erase(mtd, &erase);
76         if (ret) {
77                 set_current_state(TASK_RUNNING);
78                 remove_wait_queue(&wait_q, &wait);
79                 printk (KERN_WARNING "mtdoops: erase of region [0x%x, 0x%x] "
80                                      "on \"%s\" failed\n",
81                         erase.addr, erase.len, mtd->name);
82                 return ret;
83         }
84
85         schedule();  /* Wait for erase to finish. */
86         remove_wait_queue(&wait_q, &wait);
87
88         return 0;
89 }
90
91 static void mtdoops_inc_counter(struct mtdoops_context *cxt)
92 {
93         struct mtd_info *mtd = cxt->mtd;
94         size_t retlen;
95         u32 count;
96         int ret;
97
98         cxt->nextpage++;
99         if (cxt->nextpage > cxt->oops_pages)
100                 cxt->nextpage = 0;
101         cxt->nextcount++;
102         if (cxt->nextcount == 0xffffffff)
103                 cxt->nextcount = 0;
104
105         ret = mtd->read(mtd, cxt->nextpage * OOPS_PAGE_SIZE, 4,
106                         &retlen, (u_char *) &count);
107         if ((retlen != 4) || ((ret < 0) && (ret != -EUCLEAN))) {
108                 printk(KERN_ERR "mtdoops: Read failure at %d (%td of 4 read)"
109                                 ", err %d.\n", cxt->nextpage * OOPS_PAGE_SIZE,
110                                 retlen, ret);
111                 schedule_work(&cxt->work_erase);
112                 return;
113         }
114
115         /* See if we need to erase the next block */
116         if (count != 0xffffffff) {
117                 schedule_work(&cxt->work_erase);
118                 return;
119         }
120
121         printk(KERN_DEBUG "mtdoops: Ready %d, %d (no erase)\n",
122                         cxt->nextpage, cxt->nextcount);
123         cxt->ready = 1;
124 }
125
126 /* Scheduled work - when we can't proceed without erasing a block */
127 static void mtdoops_workfunc_erase(struct work_struct *work)
128 {
129         struct mtdoops_context *cxt =
130                         container_of(work, struct mtdoops_context, work_erase);
131         struct mtd_info *mtd = cxt->mtd;
132         int i = 0, j, ret, mod;
133
134         /* We were unregistered */
135         if (!mtd)
136                 return;
137
138         mod = (cxt->nextpage * OOPS_PAGE_SIZE) % mtd->erasesize;
139         if (mod != 0) {
140                 cxt->nextpage = cxt->nextpage + ((mtd->erasesize - mod) / OOPS_PAGE_SIZE);
141                 if (cxt->nextpage > cxt->oops_pages)
142                         cxt->nextpage = 0;
143         }
144
145         while (mtd->block_isbad) {
146                 ret = mtd->block_isbad(mtd, cxt->nextpage * OOPS_PAGE_SIZE);
147                 if (!ret)
148                         break;
149                 if (ret < 0) {
150                         printk(KERN_ERR "mtdoops: block_isbad failed, aborting.\n");
151                         return;
152                 }
153 badblock:
154                 printk(KERN_WARNING "mtdoops: Bad block at %08x\n",
155                                 cxt->nextpage * OOPS_PAGE_SIZE);
156                 i++;
157                 cxt->nextpage = cxt->nextpage + (mtd->erasesize / OOPS_PAGE_SIZE);
158                 if (cxt->nextpage > cxt->oops_pages)
159                         cxt->nextpage = 0;
160                 if (i == (cxt->oops_pages / (mtd->erasesize / OOPS_PAGE_SIZE))) {
161                         printk(KERN_ERR "mtdoops: All blocks bad!\n");
162                         return;
163                 }
164         }
165
166         for (j = 0, ret = -1; (j < 3) && (ret < 0); j++)
167                 ret = mtdoops_erase_block(mtd, cxt->nextpage * OOPS_PAGE_SIZE);
168
169         if (ret >= 0) {
170                 printk(KERN_DEBUG "mtdoops: Ready %d, %d \n", cxt->nextpage, cxt->nextcount);
171                 cxt->ready = 1;
172                 return;
173         }
174
175         if (mtd->block_markbad && (ret == -EIO)) {
176                 ret = mtd->block_markbad(mtd, cxt->nextpage * OOPS_PAGE_SIZE);
177                 if (ret < 0) {
178                         printk(KERN_ERR "mtdoops: block_markbad failed, aborting.\n");
179                         return;
180                 }
181         }
182         goto badblock;
183 }
184
185 static void mtdoops_workfunc_write(struct work_struct *work)
186 {
187         struct mtdoops_context *cxt =
188                         container_of(work, struct mtdoops_context, work_write);
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         ret = mtd->write(mtd, cxt->nextpage * OOPS_PAGE_SIZE,
198                                         OOPS_PAGE_SIZE, &retlen, cxt->oops_buf);
199
200         cxt->writecount = 0;
201
202         if ((retlen != OOPS_PAGE_SIZE) || (ret < 0))
203                 printk(KERN_ERR "mtdoops: Write failure at %d (%td of %d written), err %d.\n",
204                         cxt->nextpage * OOPS_PAGE_SIZE, retlen, OOPS_PAGE_SIZE, ret);
205
206         mtdoops_inc_counter(cxt);
207 }                                       
208
209 static void find_next_position(struct mtdoops_context *cxt)
210 {
211         struct mtd_info *mtd = cxt->mtd;
212         int ret, page, maxpos = 0;
213         u32 count, maxcount = 0xffffffff;
214         size_t retlen;
215
216         for (page = 0; page < cxt->oops_pages; page++) {
217                 ret = mtd->read(mtd, page * OOPS_PAGE_SIZE, 4, &retlen, (u_char *) &count);
218                 if ((retlen != 4) || ((ret < 0) && (ret != -EUCLEAN))) {
219                         printk(KERN_ERR "mtdoops: Read failure at %d (%td of 4 read)"
220                                 ", err %d.\n", page * OOPS_PAGE_SIZE, retlen, ret);
221                         continue;
222                 }
223
224                 if (count == 0xffffffff)
225                         continue;
226                 if (maxcount == 0xffffffff) {
227                         maxcount = count;
228                         maxpos = page;
229                 } else if ((count < 0x40000000) && (maxcount > 0xc0000000)) {
230                         maxcount = count;
231                         maxpos = page;
232                 } else if ((count > maxcount) && (count < 0xc0000000)) {
233                         maxcount = count;
234                         maxpos = page;
235                 } else if ((count > maxcount) && (count > 0xc0000000)
236                                         && (maxcount > 0x80000000)) {
237                         maxcount = count;
238                         maxpos = page;
239                 }
240         }
241         if (maxcount == 0xffffffff) {
242                 cxt->nextpage = 0;
243                 cxt->nextcount = 1;
244                 cxt->ready = 1;
245                 printk(KERN_DEBUG "mtdoops: Ready %d, %d (first init)\n",
246                                 cxt->nextpage, cxt->nextcount);
247                 return;
248         }
249
250         cxt->nextpage = maxpos;
251         cxt->nextcount = maxcount;
252
253         mtdoops_inc_counter(cxt);
254 }
255
256
257 static void mtdoops_notify_add(struct mtd_info *mtd)
258 {
259         struct mtdoops_context *cxt = &oops_cxt;
260
261         if ((mtd->index != cxt->mtd_index) || cxt->mtd_index < 0)
262                 return;
263
264         if (mtd->size < (mtd->erasesize * 2)) {
265                 printk(KERN_ERR "MTD partition %d not big enough for mtdoops\n",
266                                 mtd->index);
267                 return;
268         }
269
270         cxt->mtd = mtd;
271         cxt->oops_pages = mtd->size / OOPS_PAGE_SIZE;
272
273         find_next_position(cxt);
274
275         printk(KERN_DEBUG "mtdoops: Attached to MTD device %d\n", mtd->index);
276 }
277
278 static void mtdoops_notify_remove(struct mtd_info *mtd)
279 {
280         struct mtdoops_context *cxt = &oops_cxt;
281
282         if ((mtd->index != cxt->mtd_index) || cxt->mtd_index < 0)
283                 return;
284
285         cxt->mtd = NULL;
286         flush_scheduled_work();
287 }
288
289 static void mtdoops_console_sync(void)
290 {
291         struct mtdoops_context *cxt = &oops_cxt;
292         struct mtd_info *mtd = cxt->mtd;
293
294         if (!cxt->ready || !mtd || cxt->writecount == 0)
295                 return;
296
297         cxt->ready = 0;
298
299         schedule_work(&cxt->work_write);
300 }
301
302 static void
303 mtdoops_console_write(struct console *co, const char *s, unsigned int count)
304 {
305         struct mtdoops_context *cxt = co->data;
306         struct mtd_info *mtd = cxt->mtd;
307
308         if (!oops_in_progress) {
309                 mtdoops_console_sync();
310                 return;
311         }
312
313         if (!cxt->ready || !mtd)
314                 return;
315
316         if (cxt->writecount == 0) {
317                 u32 *stamp = cxt->oops_buf;
318                 *stamp = cxt->nextcount;
319                 cxt->writecount = 4;
320         }
321
322         if ((count + cxt->writecount) > OOPS_PAGE_SIZE)
323                 count = OOPS_PAGE_SIZE - cxt->writecount;
324
325         memcpy(cxt->oops_buf + cxt->writecount, s, count);
326         cxt->writecount += count;
327 }
328
329 static int __init mtdoops_console_setup(struct console *co, char *options)
330 {
331         struct mtdoops_context *cxt = co->data;
332
333         if (cxt->mtd_index != -1)
334                 return -EBUSY;
335         if (co->index == -1)
336                 return -EINVAL;
337
338         cxt->mtd_index = co->index;
339         return 0;
340 }
341
342 static struct mtd_notifier mtdoops_notifier = {
343         .add    = mtdoops_notify_add,
344         .remove = mtdoops_notify_remove,
345 };
346
347 static struct console mtdoops_console = {
348         .name           = "ttyMTD",
349         .write          = mtdoops_console_write,
350         .setup          = mtdoops_console_setup,
351         .unblank        = mtdoops_console_sync,
352         .flags          = CON_PRINTBUFFER,
353         .index          = -1,
354         .data           = &oops_cxt,
355 };
356
357 static int __init mtdoops_console_init(void)
358 {
359         struct mtdoops_context *cxt = &oops_cxt;
360
361         cxt->mtd_index = -1;
362         cxt->oops_buf = vmalloc(OOPS_PAGE_SIZE);
363
364         if (!cxt->oops_buf) {
365                 printk(KERN_ERR "Failed to allocate oops buffer workspace\n");
366                 return -ENOMEM;
367         }
368
369         INIT_WORK(&cxt->work_erase, mtdoops_workfunc_erase);
370         INIT_WORK(&cxt->work_write, mtdoops_workfunc_write);
371
372         register_console(&mtdoops_console);
373         register_mtd_user(&mtdoops_notifier);
374         return 0;
375 }
376
377 static void __exit mtdoops_console_exit(void)
378 {
379         struct mtdoops_context *cxt = &oops_cxt;
380
381         unregister_mtd_user(&mtdoops_notifier);
382         unregister_console(&mtdoops_console);
383         vfree(cxt->oops_buf);
384 }
385
386
387 subsys_initcall(mtdoops_console_init);
388 module_exit(mtdoops_console_exit);
389
390 MODULE_LICENSE("GPL");
391 MODULE_AUTHOR("Richard Purdie <rpurdie@openedhand.com>");
392 MODULE_DESCRIPTION("MTD Oops/Panic console logger/driver");