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