Merge branch 'linux-linaro-lsk-v4.4' into linux-linaro-lsk-v4.4-android
[firefly-linux-kernel-4.4.55.git] / drivers / mtd / mtdoops.c
1 /*
2  * MTD Oops/Panic logger
3  *
4  * Copyright © 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/interrupt.h>
33 #include <linux/mtd/mtd.h>
34 #include <linux/kmsg_dump.h>
35
36 /* Maximum MTD partition size */
37 #define MTDOOPS_MAX_MTD_SIZE (8 * 1024 * 1024)
38
39 #define MTDOOPS_KERNMSG_MAGIC 0x5d005d00
40 #define MTDOOPS_HEADER_SIZE   8
41
42 static unsigned long record_size = 4096;
43 module_param(record_size, ulong, 0400);
44 MODULE_PARM_DESC(record_size,
45                 "record size for MTD OOPS pages in bytes (default 4096)");
46
47 static char mtddev[80];
48 module_param_string(mtddev, mtddev, 80, 0400);
49 MODULE_PARM_DESC(mtddev,
50                 "name or index number of the MTD device to use");
51
52 static int dump_oops = 1;
53 module_param(dump_oops, int, 0600);
54 MODULE_PARM_DESC(dump_oops,
55                 "set to 1 to dump oopses, 0 to only dump panics (default 1)");
56
57 static struct mtdoops_context {
58         struct kmsg_dumper dump;
59
60         int mtd_index;
61         struct work_struct work_erase;
62         struct work_struct work_write;
63         struct mtd_info *mtd;
64         int oops_pages;
65         int nextpage;
66         int nextcount;
67         unsigned long *oops_page_used;
68
69         void *oops_buf;
70 } oops_cxt;
71
72 static void mark_page_used(struct mtdoops_context *cxt, int page)
73 {
74         set_bit(page, cxt->oops_page_used);
75 }
76
77 static void mark_page_unused(struct mtdoops_context *cxt, int page)
78 {
79         clear_bit(page, cxt->oops_page_used);
80 }
81
82 static int page_is_used(struct mtdoops_context *cxt, int page)
83 {
84         return test_bit(page, cxt->oops_page_used);
85 }
86
87 static void mtdoops_erase_callback(struct erase_info *done)
88 {
89         wait_queue_head_t *wait_q = (wait_queue_head_t *)done->priv;
90         wake_up(wait_q);
91 }
92
93 static int mtdoops_erase_block(struct mtdoops_context *cxt, int offset)
94 {
95         struct mtd_info *mtd = cxt->mtd;
96         u32 start_page_offset = mtd_div_by_eb(offset, mtd) * mtd->erasesize;
97         u32 start_page = start_page_offset / record_size;
98         u32 erase_pages = mtd->erasesize / record_size;
99         struct erase_info erase;
100         DECLARE_WAITQUEUE(wait, current);
101         wait_queue_head_t wait_q;
102         int ret;
103         int page;
104
105         init_waitqueue_head(&wait_q);
106         erase.mtd = mtd;
107         erase.callback = mtdoops_erase_callback;
108         erase.addr = offset;
109         erase.len = mtd->erasesize;
110         erase.priv = (u_long)&wait_q;
111
112         set_current_state(TASK_INTERRUPTIBLE);
113         add_wait_queue(&wait_q, &wait);
114
115         ret = mtd_erase(mtd, &erase);
116         if (ret) {
117                 set_current_state(TASK_RUNNING);
118                 remove_wait_queue(&wait_q, &wait);
119                 printk(KERN_WARNING "mtdoops: erase of region [0x%llx, 0x%llx] on \"%s\" failed\n",
120                        (unsigned long long)erase.addr,
121                        (unsigned long long)erase.len, mtddev);
122                 return ret;
123         }
124
125         schedule();  /* Wait for erase to finish. */
126         remove_wait_queue(&wait_q, &wait);
127
128         /* Mark pages as unused */
129         for (page = start_page; page < start_page + erase_pages; page++)
130                 mark_page_unused(cxt, page);
131
132         return 0;
133 }
134
135 static void mtdoops_inc_counter(struct mtdoops_context *cxt)
136 {
137         cxt->nextpage++;
138         if (cxt->nextpage >= cxt->oops_pages)
139                 cxt->nextpage = 0;
140         cxt->nextcount++;
141         if (cxt->nextcount == 0xffffffff)
142                 cxt->nextcount = 0;
143
144         if (page_is_used(cxt, cxt->nextpage)) {
145                 schedule_work(&cxt->work_erase);
146                 return;
147         }
148
149         printk(KERN_DEBUG "mtdoops: ready %d, %d (no erase)\n",
150                cxt->nextpage, cxt->nextcount);
151 }
152
153 /* Scheduled work - when we can't proceed without erasing a block */
154 static void mtdoops_workfunc_erase(struct work_struct *work)
155 {
156         struct mtdoops_context *cxt =
157                         container_of(work, struct mtdoops_context, work_erase);
158         struct mtd_info *mtd = cxt->mtd;
159         int i = 0, j, ret, mod;
160
161         /* We were unregistered */
162         if (!mtd)
163                 return;
164
165         mod = (cxt->nextpage * record_size) % mtd->erasesize;
166         if (mod != 0) {
167                 cxt->nextpage = cxt->nextpage + ((mtd->erasesize - mod) / record_size);
168                 if (cxt->nextpage >= cxt->oops_pages)
169                         cxt->nextpage = 0;
170         }
171
172         while ((ret = mtd_block_isbad(mtd, cxt->nextpage * record_size)) > 0) {
173 badblock:
174                 printk(KERN_WARNING "mtdoops: bad block at %08lx\n",
175                        cxt->nextpage * record_size);
176                 i++;
177                 cxt->nextpage = cxt->nextpage + (mtd->erasesize / record_size);
178                 if (cxt->nextpage >= cxt->oops_pages)
179                         cxt->nextpage = 0;
180                 if (i == cxt->oops_pages / (mtd->erasesize / record_size)) {
181                         printk(KERN_ERR "mtdoops: all blocks bad!\n");
182                         return;
183                 }
184         }
185
186         if (ret < 0) {
187                 printk(KERN_ERR "mtdoops: mtd_block_isbad failed, aborting\n");
188                 return;
189         }
190
191         for (j = 0, ret = -1; (j < 3) && (ret < 0); j++)
192                 ret = mtdoops_erase_block(cxt, cxt->nextpage * record_size);
193
194         if (ret >= 0) {
195                 printk(KERN_DEBUG "mtdoops: ready %d, %d\n",
196                        cxt->nextpage, cxt->nextcount);
197                 return;
198         }
199
200         if (ret == -EIO) {
201                 ret = mtd_block_markbad(mtd, cxt->nextpage * record_size);
202                 if (ret < 0 && ret != -EOPNOTSUPP) {
203                         printk(KERN_ERR "mtdoops: block_markbad failed, aborting\n");
204                         return;
205                 }
206         }
207         goto badblock;
208 }
209
210 static void mtdoops_write(struct mtdoops_context *cxt, int panic)
211 {
212         struct mtd_info *mtd = cxt->mtd;
213         size_t retlen;
214         u32 *hdr;
215         int ret;
216
217         /* Add mtdoops header to the buffer */
218         hdr = cxt->oops_buf;
219         hdr[0] = cxt->nextcount;
220         hdr[1] = MTDOOPS_KERNMSG_MAGIC;
221
222         if (panic) {
223                 ret = mtd_panic_write(mtd, cxt->nextpage * record_size,
224                                       record_size, &retlen, cxt->oops_buf);
225                 if (ret == -EOPNOTSUPP) {
226                         printk(KERN_ERR "mtdoops: Cannot write from panic without panic_write\n");
227                         return;
228                 }
229         } else
230                 ret = mtd_write(mtd, cxt->nextpage * record_size,
231                                 record_size, &retlen, cxt->oops_buf);
232
233         if (retlen != record_size || ret < 0)
234                 printk(KERN_ERR "mtdoops: write failure at %ld (%td of %ld written), error %d\n",
235                        cxt->nextpage * record_size, retlen, record_size, ret);
236         mark_page_used(cxt, cxt->nextpage);
237         memset(cxt->oops_buf, 0xff, record_size);
238
239         mtdoops_inc_counter(cxt);
240 }
241
242 static void mtdoops_workfunc_write(struct work_struct *work)
243 {
244         struct mtdoops_context *cxt =
245                         container_of(work, struct mtdoops_context, work_write);
246
247         mtdoops_write(cxt, 0);
248 }
249
250 static void find_next_position(struct mtdoops_context *cxt)
251 {
252         struct mtd_info *mtd = cxt->mtd;
253         int ret, page, maxpos = 0;
254         u32 count[2], maxcount = 0xffffffff;
255         size_t retlen;
256
257         for (page = 0; page < cxt->oops_pages; page++) {
258                 if (mtd_block_isbad(mtd, page * record_size))
259                         continue;
260                 /* Assume the page is used */
261                 mark_page_used(cxt, page);
262                 ret = mtd_read(mtd, page * record_size, MTDOOPS_HEADER_SIZE,
263                                &retlen, (u_char *)&count[0]);
264                 if (retlen != MTDOOPS_HEADER_SIZE ||
265                                 (ret < 0 && !mtd_is_bitflip(ret))) {
266                         printk(KERN_ERR "mtdoops: read failure at %ld (%td of %d read), err %d\n",
267                                page * record_size, retlen,
268                                MTDOOPS_HEADER_SIZE, ret);
269                         continue;
270                 }
271
272                 if (count[0] == 0xffffffff && count[1] == 0xffffffff)
273                         mark_page_unused(cxt, page);
274                 if (count[0] == 0xffffffff || count[1] != MTDOOPS_KERNMSG_MAGIC)
275                         continue;
276                 if (maxcount == 0xffffffff) {
277                         maxcount = count[0];
278                         maxpos = page;
279                 } else if (count[0] < 0x40000000 && maxcount > 0xc0000000) {
280                         maxcount = count[0];
281                         maxpos = page;
282                 } else if (count[0] > maxcount && count[0] < 0xc0000000) {
283                         maxcount = count[0];
284                         maxpos = page;
285                 } else if (count[0] > maxcount && count[0] > 0xc0000000
286                                         && maxcount > 0x80000000) {
287                         maxcount = count[0];
288                         maxpos = page;
289                 }
290         }
291         if (maxcount == 0xffffffff) {
292                 cxt->nextpage = cxt->oops_pages - 1;
293                 cxt->nextcount = 0;
294         }
295         else {
296                 cxt->nextpage = maxpos;
297                 cxt->nextcount = maxcount;
298         }
299
300         mtdoops_inc_counter(cxt);
301 }
302
303 static void mtdoops_do_dump(struct kmsg_dumper *dumper,
304                             enum kmsg_dump_reason reason)
305 {
306         struct mtdoops_context *cxt = container_of(dumper,
307                         struct mtdoops_context, dump);
308
309         /* Only dump oopses if dump_oops is set */
310         if (reason == KMSG_DUMP_OOPS && !dump_oops)
311                 return;
312
313         kmsg_dump_get_buffer(dumper, true, cxt->oops_buf + MTDOOPS_HEADER_SIZE,
314                              record_size - MTDOOPS_HEADER_SIZE, NULL);
315
316         /* Panics must be written immediately */
317         if (reason != KMSG_DUMP_OOPS)
318                 mtdoops_write(cxt, 1);
319
320         /* For other cases, schedule work to write it "nicely" */
321         schedule_work(&cxt->work_write);
322 }
323
324 static void mtdoops_notify_add(struct mtd_info *mtd)
325 {
326         struct mtdoops_context *cxt = &oops_cxt;
327         u64 mtdoops_pages = div_u64(mtd->size, record_size);
328         int err;
329
330         if (!strcmp(mtd->name, mtddev))
331                 cxt->mtd_index = mtd->index;
332
333         if (mtd->index != cxt->mtd_index || cxt->mtd_index < 0)
334                 return;
335
336         if (mtd->size < mtd->erasesize * 2) {
337                 printk(KERN_ERR "mtdoops: MTD partition %d not big enough for mtdoops\n",
338                        mtd->index);
339                 return;
340         }
341         if (mtd->erasesize < record_size) {
342                 printk(KERN_ERR "mtdoops: eraseblock size of MTD partition %d too small\n",
343                        mtd->index);
344                 return;
345         }
346         if (mtd->size > MTDOOPS_MAX_MTD_SIZE) {
347                 printk(KERN_ERR "mtdoops: mtd%d is too large (limit is %d MiB)\n",
348                        mtd->index, MTDOOPS_MAX_MTD_SIZE / 1024 / 1024);
349                 return;
350         }
351
352         /* oops_page_used is a bit field */
353         cxt->oops_page_used = vmalloc(DIV_ROUND_UP(mtdoops_pages,
354                         BITS_PER_LONG) * sizeof(unsigned long));
355         if (!cxt->oops_page_used) {
356                 printk(KERN_ERR "mtdoops: could not allocate page array\n");
357                 return;
358         }
359
360         cxt->dump.max_reason = KMSG_DUMP_OOPS;
361         cxt->dump.dump = mtdoops_do_dump;
362         err = kmsg_dump_register(&cxt->dump);
363         if (err) {
364                 printk(KERN_ERR "mtdoops: registering kmsg dumper failed, error %d\n", err);
365                 vfree(cxt->oops_page_used);
366                 cxt->oops_page_used = NULL;
367                 return;
368         }
369
370         cxt->mtd = mtd;
371         cxt->oops_pages = (int)mtd->size / record_size;
372         find_next_position(cxt);
373         printk(KERN_INFO "mtdoops: Attached to MTD device %d\n", mtd->index);
374 }
375
376 static void mtdoops_notify_remove(struct mtd_info *mtd)
377 {
378         struct mtdoops_context *cxt = &oops_cxt;
379
380         if (mtd->index != cxt->mtd_index || cxt->mtd_index < 0)
381                 return;
382
383         if (kmsg_dump_unregister(&cxt->dump) < 0)
384                 printk(KERN_WARNING "mtdoops: could not unregister kmsg_dumper\n");
385
386         cxt->mtd = NULL;
387         flush_work(&cxt->work_erase);
388         flush_work(&cxt->work_write);
389 }
390
391
392 static struct mtd_notifier mtdoops_notifier = {
393         .add    = mtdoops_notify_add,
394         .remove = mtdoops_notify_remove,
395 };
396
397 static int __init mtdoops_init(void)
398 {
399         struct mtdoops_context *cxt = &oops_cxt;
400         int mtd_index;
401         char *endp;
402
403         if (strlen(mtddev) == 0) {
404                 printk(KERN_ERR "mtdoops: mtd device (mtddev=name/number) must be supplied\n");
405                 return -EINVAL;
406         }
407         if ((record_size & 4095) != 0) {
408                 printk(KERN_ERR "mtdoops: record_size must be a multiple of 4096\n");
409                 return -EINVAL;
410         }
411         if (record_size < 4096) {
412                 printk(KERN_ERR "mtdoops: record_size must be over 4096 bytes\n");
413                 return -EINVAL;
414         }
415
416         /* Setup the MTD device to use */
417         cxt->mtd_index = -1;
418         mtd_index = simple_strtoul(mtddev, &endp, 0);
419         if (*endp == '\0')
420                 cxt->mtd_index = mtd_index;
421
422         cxt->oops_buf = vmalloc(record_size);
423         if (!cxt->oops_buf) {
424                 printk(KERN_ERR "mtdoops: failed to allocate buffer workspace\n");
425                 return -ENOMEM;
426         }
427         memset(cxt->oops_buf, 0xff, record_size);
428
429         INIT_WORK(&cxt->work_erase, mtdoops_workfunc_erase);
430         INIT_WORK(&cxt->work_write, mtdoops_workfunc_write);
431
432         register_mtd_user(&mtdoops_notifier);
433         return 0;
434 }
435
436 static void __exit mtdoops_exit(void)
437 {
438         struct mtdoops_context *cxt = &oops_cxt;
439
440         unregister_mtd_user(&mtdoops_notifier);
441         vfree(cxt->oops_buf);
442         vfree(cxt->oops_page_used);
443 }
444
445
446 module_init(mtdoops_init);
447 module_exit(mtdoops_exit);
448
449 MODULE_LICENSE("GPL");
450 MODULE_AUTHOR("Richard Purdie <rpurdie@openedhand.com>");
451 MODULE_DESCRIPTION("MTD Oops/Panic console logger/driver");