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
42static unsigned long record_size = 4096;
43module_param(record_size, ulong, 0400);
44MODULE_PARM_DESC(record_size,
45		"record size for MTD OOPS pages in bytes (default 4096)");
46
47static char mtddev[80];
48module_param_string(mtddev, mtddev, 80, 0400);
49MODULE_PARM_DESC(mtddev,
50		"name or index number of the MTD device to use");
51
52static int dump_oops = 1;
53module_param(dump_oops, int, 0600);
54MODULE_PARM_DESC(dump_oops,
55		"set to 1 to dump oopses, 0 to only dump panics (default 1)");
56
57static 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
72static void mark_page_used(struct mtdoops_context *cxt, int page)
73{
74	set_bit(page, cxt->oops_page_used);
75}
76
77static void mark_page_unused(struct mtdoops_context *cxt, int page)
78{
79	clear_bit(page, cxt->oops_page_used);
80}
81
82static int page_is_used(struct mtdoops_context *cxt, int page)
83{
84	return test_bit(page, cxt->oops_page_used);
85}
86
87static 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
93static 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
135static 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 */
154static 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) {
173badblock:
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
210static 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
242static 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
250static 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
303static 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
324static 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
376static 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
392static struct mtd_notifier mtdoops_notifier = {
393	.add	= mtdoops_notify_add,
394	.remove	= mtdoops_notify_remove,
395};
396
397static 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
436static 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
446module_init(mtdoops_init);
447module_exit(mtdoops_exit);
448
449MODULE_LICENSE("GPL");
450MODULE_AUTHOR("Richard Purdie <rpurdie@openedhand.com>");
451MODULE_DESCRIPTION("MTD Oops/Panic console logger/driver");
452