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
mtdoops_erase_callback(struct erase_info * done)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
mtdoops_erase_block(struct mtd_info * mtd,int offset)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%llx, 0x%llx] "
84 "on \"%s\" failed\n",
85 (unsigned long long)erase.addr, (unsigned long long)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
mtdoops_inc_counter(struct mtdoops_context * cxt)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 */
mtdoops_workfunc_erase(struct work_struct * work)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
mtdoops_write(struct mtdoops_context * cxt,int panic)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
mtdoops_workfunc_write(struct work_struct * work)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
find_next_position(struct mtdoops_context * cxt)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
mtdoops_notify_add(struct mtd_info * mtd)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 if (mtd->size > INT_MAX)
293 cxt->oops_pages = INT_MAX / OOPS_PAGE_SIZE;
294 else
295 cxt->oops_pages = (int)mtd->size / OOPS_PAGE_SIZE;
296
297 find_next_position(cxt);
298
299 printk(KERN_INFO "mtdoops: Attached to MTD device %d\n", mtd->index);
300 }
301
mtdoops_notify_remove(struct mtd_info * mtd)302 static void mtdoops_notify_remove(struct mtd_info *mtd)
303 {
304 struct mtdoops_context *cxt = &oops_cxt;
305
306 if ((mtd->index != cxt->mtd_index) || cxt->mtd_index < 0)
307 return;
308
309 cxt->mtd = NULL;
310 flush_scheduled_work();
311 }
312
mtdoops_console_sync(void)313 static void mtdoops_console_sync(void)
314 {
315 struct mtdoops_context *cxt = &oops_cxt;
316 struct mtd_info *mtd = cxt->mtd;
317 unsigned long flags;
318
319 if (!cxt->ready || !mtd || cxt->writecount == 0)
320 return;
321
322 /*
323 * Once ready is 0 and we've held the lock no further writes to the
324 * buffer will happen
325 */
326 spin_lock_irqsave(&cxt->writecount_lock, flags);
327 if (!cxt->ready) {
328 spin_unlock_irqrestore(&cxt->writecount_lock, flags);
329 return;
330 }
331 cxt->ready = 0;
332 spin_unlock_irqrestore(&cxt->writecount_lock, flags);
333
334 if (mtd->panic_write && in_interrupt())
335 /* Interrupt context, we're going to panic so try and log */
336 mtdoops_write(cxt, 1);
337 else
338 schedule_work(&cxt->work_write);
339 }
340
341 static void
mtdoops_console_write(struct console * co,const char * s,unsigned int count)342 mtdoops_console_write(struct console *co, const char *s, unsigned int count)
343 {
344 struct mtdoops_context *cxt = co->data;
345 struct mtd_info *mtd = cxt->mtd;
346 unsigned long flags;
347
348 if (!oops_in_progress) {
349 mtdoops_console_sync();
350 return;
351 }
352
353 if (!cxt->ready || !mtd)
354 return;
355
356 /* Locking on writecount ensures sequential writes to the buffer */
357 spin_lock_irqsave(&cxt->writecount_lock, flags);
358
359 /* Check ready status didn't change whilst waiting for the lock */
360 if (!cxt->ready)
361 return;
362
363 if (cxt->writecount == 0) {
364 u32 *stamp = cxt->oops_buf;
365 *stamp++ = cxt->nextcount;
366 *stamp = MTDOOPS_KERNMSG_MAGIC;
367 cxt->writecount = 8;
368 }
369
370 if ((count + cxt->writecount) > OOPS_PAGE_SIZE)
371 count = OOPS_PAGE_SIZE - cxt->writecount;
372
373 memcpy(cxt->oops_buf + cxt->writecount, s, count);
374 cxt->writecount += count;
375
376 spin_unlock_irqrestore(&cxt->writecount_lock, flags);
377
378 if (cxt->writecount == OOPS_PAGE_SIZE)
379 mtdoops_console_sync();
380 }
381
mtdoops_console_setup(struct console * co,char * options)382 static int __init mtdoops_console_setup(struct console *co, char *options)
383 {
384 struct mtdoops_context *cxt = co->data;
385
386 if (cxt->mtd_index != -1)
387 return -EBUSY;
388 if (co->index == -1)
389 return -EINVAL;
390
391 cxt->mtd_index = co->index;
392 return 0;
393 }
394
395 static struct mtd_notifier mtdoops_notifier = {
396 .add = mtdoops_notify_add,
397 .remove = mtdoops_notify_remove,
398 };
399
400 static struct console mtdoops_console = {
401 .name = "ttyMTD",
402 .write = mtdoops_console_write,
403 .setup = mtdoops_console_setup,
404 .unblank = mtdoops_console_sync,
405 .index = -1,
406 .data = &oops_cxt,
407 };
408
mtdoops_console_init(void)409 static int __init mtdoops_console_init(void)
410 {
411 struct mtdoops_context *cxt = &oops_cxt;
412
413 cxt->mtd_index = -1;
414 cxt->oops_buf = vmalloc(OOPS_PAGE_SIZE);
415
416 if (!cxt->oops_buf) {
417 printk(KERN_ERR "Failed to allocate mtdoops buffer workspace\n");
418 return -ENOMEM;
419 }
420
421 INIT_WORK(&cxt->work_erase, mtdoops_workfunc_erase);
422 INIT_WORK(&cxt->work_write, mtdoops_workfunc_write);
423
424 register_console(&mtdoops_console);
425 register_mtd_user(&mtdoops_notifier);
426 return 0;
427 }
428
mtdoops_console_exit(void)429 static void __exit mtdoops_console_exit(void)
430 {
431 struct mtdoops_context *cxt = &oops_cxt;
432
433 unregister_mtd_user(&mtdoops_notifier);
434 unregister_console(&mtdoops_console);
435 vfree(cxt->oops_buf);
436 }
437
438
439 subsys_initcall(mtdoops_console_init);
440 module_exit(mtdoops_console_exit);
441
442 MODULE_LICENSE("GPL");
443 MODULE_AUTHOR("Richard Purdie <rpurdie@openedhand.com>");
444 MODULE_DESCRIPTION("MTD Oops/Panic console logger/driver");
445