[linux.git] / drivers / mtd / mtdoops.c

/*
 * MTD Oops/Panic logger
 *
 * Copyright © 2007 Nokia Corporation. All rights reserved.
 *
 * Author: Richard Purdie <[email protected]>
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * version 2 as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
 * 02110-1301 USA
 *
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/console.h>
#include <linux/vmalloc.h>
#include <linux/workqueue.h>
#include <linux/sched.h>
#include <linux/wait.h>
#include <linux/delay.h>
#include <linux/interrupt.h>
#include <linux/mtd/mtd.h>
#include <linux/kmsg_dump.h>

/* Maximum MTD partition size */
#define MTDOOPS_MAX_MTD_SIZE (8 * 1024 * 1024)

#define MTDOOPS_KERNMSG_MAGIC 0x5d005d00
#define MTDOOPS_HEADER_SIZE   8

static unsigned long record_size = 4096;
module_param(record_size, ulong, 0400);
MODULE_PARM_DESC(record_size,
		"record size for MTD OOPS pages in bytes (default 4096)");

static char mtddev[80];
module_param_string(mtddev, mtddev, 80, 0400);
MODULE_PARM_DESC(mtddev,
		"name or index number of the MTD device to use");

static int dump_oops = 1;
module_param(dump_oops, int, 0600);
MODULE_PARM_DESC(dump_oops,
		"set to 1 to dump oopses, 0 to only dump panics (default 1)");

static struct mtdoops_context {
	struct kmsg_dumper dump;

	int mtd_index;
	struct work_struct work_erase;
	struct work_struct work_write;
	struct mtd_info *mtd;
	int oops_pages;
	int nextpage;
	int nextcount;
	unsigned long *oops_page_used;

	void *oops_buf;
} oops_cxt;

static void mark_page_used(struct mtdoops_context *cxt, int page)
{
	set_bit(page, cxt->oops_page_used);
}

static void mark_page_unused(struct mtdoops_context *cxt, int page)
{
	clear_bit(page, cxt->oops_page_used);
}

static int page_is_used(struct mtdoops_context *cxt, int page)
{
	return test_bit(page, cxt->oops_page_used);
}

static int mtdoops_erase_block(struct mtdoops_context *cxt, int offset)
{
	struct mtd_info *mtd = cxt->mtd;
	u32 start_page_offset = mtd_div_by_eb(offset, mtd) * mtd->erasesize;
	u32 start_page = start_page_offset / record_size;
	u32 erase_pages = mtd->erasesize / record_size;
	struct erase_info erase;
	int ret;
	int page;

	erase.addr = offset;
	erase.len = mtd->erasesize;

	ret = mtd_erase(mtd, &erase);
	if (ret) {
		printk(KERN_WARNING "mtdoops: erase of region [0x%llx, 0x%llx] on \"%s\" failed\n",
		       (unsigned long long)erase.addr,
		       (unsigned long long)erase.len, mtddev);
		return ret;
	}

	/* Mark pages as unused */
	for (page = start_page; page < start_page + erase_pages; page++)
		mark_page_unused(cxt, page);

	return 0;
}

static void mtdoops_inc_counter(struct mtdoops_context *cxt)
{
	cxt->nextpage++;
	if (cxt->nextpage >= cxt->oops_pages)
		cxt->nextpage = 0;
	cxt->nextcount++;
	if (cxt->nextcount == 0xffffffff)
		cxt->nextcount = 0;

	if (page_is_used(cxt, cxt->nextpage)) {
		schedule_work(&cxt->work_erase);
		return;
	}

	printk(KERN_DEBUG "mtdoops: ready %d, %d (no erase)\n",
	       cxt->nextpage, cxt->nextcount);
}

/* Scheduled work - when we can't proceed without erasing a block */
static void mtdoops_workfunc_erase(struct work_struct *work)
{
	struct mtdoops_context *cxt =
			container_of(work, struct mtdoops_context, work_erase);
	struct mtd_info *mtd = cxt->mtd;
	int i = 0, j, ret, mod;

	/* We were unregistered */
	if (!mtd)
		return;

	mod = (cxt->nextpage * record_size) % mtd->erasesize;
	if (mod != 0) {
		cxt->nextpage = cxt->nextpage + ((mtd->erasesize - mod) / record_size);
		if (cxt->nextpage >= cxt->oops_pages)
			cxt->nextpage = 0;
	}

	while ((ret = mtd_block_isbad(mtd, cxt->nextpage * record_size)) > 0) {
badblock:
		printk(KERN_WARNING "mtdoops: bad block at %08lx\n",
		       cxt->nextpage * record_size);
		i++;
		cxt->nextpage = cxt->nextpage + (mtd->erasesize / record_size);
		if (cxt->nextpage >= cxt->oops_pages)
			cxt->nextpage = 0;
		if (i == cxt->oops_pages / (mtd->erasesize / record_size)) {
			printk(KERN_ERR "mtdoops: all blocks bad!\n");
			return;
		}
	}

	if (ret < 0) {
		printk(KERN_ERR "mtdoops: mtd_block_isbad failed, aborting\n");
		return;
	}

	for (j = 0, ret = -1; (j < 3) && (ret < 0); j++)
		ret = mtdoops_erase_block(cxt, cxt->nextpage * record_size);

	if (ret >= 0) {
		printk(KERN_DEBUG "mtdoops: ready %d, %d\n",
		       cxt->nextpage, cxt->nextcount);
		return;
	}

	if (ret == -EIO) {
		ret = mtd_block_markbad(mtd, cxt->nextpage * record_size);
		if (ret < 0 && ret != -EOPNOTSUPP) {
			printk(KERN_ERR "mtdoops: block_markbad failed, aborting\n");
			return;
		}
	}
	goto badblock;
}

static void mtdoops_write(struct mtdoops_context *cxt, int panic)
{
	struct mtd_info *mtd = cxt->mtd;
	size_t retlen;
	u32 *hdr;
	int ret;

	/* Add mtdoops header to the buffer */
	hdr = cxt->oops_buf;
	hdr[0] = cxt->nextcount;
	hdr[1] = MTDOOPS_KERNMSG_MAGIC;

	if (panic) {
		ret = mtd_panic_write(mtd, cxt->nextpage * record_size,
				      record_size, &retlen, cxt->oops_buf);
		if (ret == -EOPNOTSUPP) {
			printk(KERN_ERR "mtdoops: Cannot write from panic without panic_write\n");
			return;
		}
	} else
		ret = mtd_write(mtd, cxt->nextpage * record_size,
				record_size, &retlen, cxt->oops_buf);

	if (retlen != record_size || ret < 0)
		printk(KERN_ERR "mtdoops: write failure at %ld (%td of %ld written), error %d\n",
		       cxt->nextpage * record_size, retlen, record_size, ret);
	mark_page_used(cxt, cxt->nextpage);
	memset(cxt->oops_buf, 0xff, record_size);

	mtdoops_inc_counter(cxt);
}

static void mtdoops_workfunc_write(struct work_struct *work)
{
	struct mtdoops_context *cxt =
			container_of(work, struct mtdoops_context, work_write);

	mtdoops_write(cxt, 0);
}

static void find_next_position(struct mtdoops_context *cxt)
{
	struct mtd_info *mtd = cxt->mtd;
	int ret, page, maxpos = 0;
	u32 count[2], maxcount = 0xffffffff;
	size_t retlen;

	for (page = 0; page < cxt->oops_pages; page++) {
		if (mtd_block_isbad(mtd, page * record_size))
			continue;
		/* Assume the page is used */
		mark_page_used(cxt, page);
		ret = mtd_read(mtd, page * record_size, MTDOOPS_HEADER_SIZE,
			       &retlen, (u_char *)&count[0]);
		if (retlen != MTDOOPS_HEADER_SIZE ||
				(ret < 0 && !mtd_is_bitflip(ret))) {
			printk(KERN_ERR "mtdoops: read failure at %ld (%td of %d read), err %d\n",
			       page * record_size, retlen,
			       MTDOOPS_HEADER_SIZE, ret);
			continue;
		}

		if (count[0] == 0xffffffff && count[1] == 0xffffffff)
			mark_page_unused(cxt, page);
		if (count[0] == 0xffffffff || count[1] != MTDOOPS_KERNMSG_MAGIC)
			continue;
		if (maxcount == 0xffffffff) {
			maxcount = count[0];
			maxpos = page;
		} else if (count[0] < 0x40000000 && maxcount > 0xc0000000) {
			maxcount = count[0];
			maxpos = page;
		} else if (count[0] > maxcount && count[0] < 0xc0000000) {
			maxcount = count[0];
			maxpos = page;
		} else if (count[0] > maxcount && count[0] > 0xc0000000
					&& maxcount > 0x80000000) {
			maxcount = count[0];
			maxpos = page;
		}
	}
	if (maxcount == 0xffffffff) {
		cxt->nextpage = cxt->oops_pages - 1;
		cxt->nextcount = 0;
	}
	else {
		cxt->nextpage = maxpos;
		cxt->nextcount = maxcount;
	}

	mtdoops_inc_counter(cxt);
}

static void mtdoops_do_dump(struct kmsg_dumper *dumper,
			    enum kmsg_dump_reason reason)
{
	struct mtdoops_context *cxt = container_of(dumper,
			struct mtdoops_context, dump);

	/* Only dump oopses if dump_oops is set */
	if (reason == KMSG_DUMP_OOPS && !dump_oops)
		return;

	kmsg_dump_get_buffer(dumper, true, cxt->oops_buf + MTDOOPS_HEADER_SIZE,
			     record_size - MTDOOPS_HEADER_SIZE, NULL);

	/* Panics must be written immediately */
	if (reason != KMSG_DUMP_OOPS)
		mtdoops_write(cxt, 1);

	/* For other cases, schedule work to write it "nicely" */
	schedule_work(&cxt->work_write);
}

static void mtdoops_notify_add(struct mtd_info *mtd)
{
	struct mtdoops_context *cxt = &oops_cxt;
	u64 mtdoops_pages = div_u64(mtd->size, record_size);
	int err;

	if (!strcmp(mtd->name, mtddev))
		cxt->mtd_index = mtd->index;

	if (mtd->index != cxt->mtd_index || cxt->mtd_index < 0)
		return;

	if (mtd->size < mtd->erasesize * 2) {
		printk(KERN_ERR "mtdoops: MTD partition %d not big enough for mtdoops\n",
		       mtd->index);
		return;
	}
	if (mtd->erasesize < record_size) {
		printk(KERN_ERR "mtdoops: eraseblock size of MTD partition %d too small\n",
		       mtd->index);
		return;
	}
	if (mtd->size > MTDOOPS_MAX_MTD_SIZE) {
		printk(KERN_ERR "mtdoops: mtd%d is too large (limit is %d MiB)\n",
		       mtd->index, MTDOOPS_MAX_MTD_SIZE / 1024 / 1024);
		return;
	}

	/* oops_page_used is a bit field */
	cxt->oops_page_used =
		vmalloc(array_size(sizeof(unsigned long),
				   DIV_ROUND_UP(mtdoops_pages,
						BITS_PER_LONG)));
	if (!cxt->oops_page_used) {
		printk(KERN_ERR "mtdoops: could not allocate page array\n");
		return;
	}

	cxt->dump.max_reason = KMSG_DUMP_OOPS;
	cxt->dump.dump = mtdoops_do_dump;
	err = kmsg_dump_register(&cxt->dump);
	if (err) {
		printk(KERN_ERR "mtdoops: registering kmsg dumper failed, error %d\n", err);
		vfree(cxt->oops_page_used);
		cxt->oops_page_used = NULL;
		return;
	}

	cxt->mtd = mtd;
	cxt->oops_pages = (int)mtd->size / record_size;
	find_next_position(cxt);
	printk(KERN_INFO "mtdoops: Attached to MTD device %d\n", mtd->index);
}

static void mtdoops_notify_remove(struct mtd_info *mtd)
{
	struct mtdoops_context *cxt = &oops_cxt;

	if (mtd->index != cxt->mtd_index || cxt->mtd_index < 0)
		return;

	if (kmsg_dump_unregister(&cxt->dump) < 0)
		printk(KERN_WARNING "mtdoops: could not unregister kmsg_dumper\n");

	cxt->mtd = NULL;
	flush_work(&cxt->work_erase);
	flush_work(&cxt->work_write);
}


static struct mtd_notifier mtdoops_notifier = {
	.add	= mtdoops_notify_add,
	.remove	= mtdoops_notify_remove,
};

static int __init mtdoops_init(void)
{
	struct mtdoops_context *cxt = &oops_cxt;
	int mtd_index;
	char *endp;

	if (strlen(mtddev) == 0) {
		printk(KERN_ERR "mtdoops: mtd device (mtddev=name/number) must be supplied\n");
		return -EINVAL;
	}
	if ((record_size & 4095) != 0) {
		printk(KERN_ERR "mtdoops: record_size must be a multiple of 4096\n");
		return -EINVAL;
	}
	if (record_size < 4096) {
		printk(KERN_ERR "mtdoops: record_size must be over 4096 bytes\n");
		return -EINVAL;
	}

	/* Setup the MTD device to use */
	cxt->mtd_index = -1;
	mtd_index = simple_strtoul(mtddev, &endp, 0);
	if (*endp == '\0')
		cxt->mtd_index = mtd_index;

	cxt->oops_buf = vmalloc(record_size);
	if (!cxt->oops_buf) {
		printk(KERN_ERR "mtdoops: failed to allocate buffer workspace\n");
		return -ENOMEM;
	}
	memset(cxt->oops_buf, 0xff, record_size);

	INIT_WORK(&cxt->work_erase, mtdoops_workfunc_erase);
	INIT_WORK(&cxt->work_write, mtdoops_workfunc_write);

	register_mtd_user(&mtdoops_notifier);
	return 0;
}

static void __exit mtdoops_exit(void)
{
	struct mtdoops_context *cxt = &oops_cxt;

	unregister_mtd_user(&mtdoops_notifier);
	vfree(cxt->oops_buf);
	vfree(cxt->oops_page_used);
}


module_init(mtdoops_init);
module_exit(mtdoops_exit);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Richard Purdie <[email protected]>");
MODULE_DESCRIPTION("MTD Oops/Panic console logger/driver");
Commit	Line	Data
4b23aff0 RP	1	/*
	2	* MTD Oops/Panic logger
	3	*
a1452a37	4	* Copyright © 2007 Nokia Corporation. All rights reserved.
4b23aff0 RP	5	*
	6	* Author: Richard Purdie <[email protected]>
	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>
621e4f8e	31	#include <linux/delay.h>
f9f7dd22	32	#include <linux/interrupt.h>
4b23aff0	33	#include <linux/mtd/mtd.h>
2e386e4b	34	#include <linux/kmsg_dump.h>
4b23aff0	35
1114e3d0 SK	36	/* Maximum MTD partition size */
	37	#define MTDOOPS_MAX_MTD_SIZE (8 * 1024 * 1024)
	38
f0482ee3	39	#define MTDOOPS_KERNMSG_MAGIC 0x5d005d00
2e386e4b	40	#define MTDOOPS_HEADER_SIZE 8
9507b0c8 SK	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)");
4b23aff0	46
2e386e4b SK	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
7903cbab	57	static struct mtdoops_context {
2e386e4b SK	58	struct kmsg_dumper dump;
2e386e4b SK	59
4b23aff0	60	int mtd_index;
6ce0a856 RP	61	struct work_struct work_erase;
6ce0a856 RP	62	struct work_struct work_write;
4b23aff0 RP	63	struct mtd_info *mtd;
	64	int oops_pages;
	65	int nextpage;
	66	int nextcount;
be95745f	67	unsigned long *oops_page_used;
4b23aff0 RP	68
4b23aff0 RP	69	void *oops_buf;
4b23aff0 RP	70	} oops_cxt;
4b23aff0 RP	71
be95745f SK	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
be95745f	87	static int mtdoops_erase_block(struct mtdoops_context *cxt, int offset)
4b23aff0	88	{
be95745f SK	89	struct mtd_info *mtd = cxt->mtd;
be95745f SK	90	u32 start_page_offset = mtd_div_by_eb(offset, mtd) * mtd->erasesize;
9507b0c8 SK	91	u32 start_page = start_page_offset / record_size;
9507b0c8 SK	92	u32 erase_pages = mtd->erasesize / record_size;
4b23aff0	93	struct erase_info erase;
4b23aff0	94	int ret;
be95745f	95	int page;
4b23aff0	96
4b23aff0	97	erase.addr = offset;
79dcd8e9	98	erase.len = mtd->erasesize;
4b23aff0	99
7e1f0dc0	100	ret = mtd_erase(mtd, &erase);
4b23aff0	101	if (ret) {
a15b124f AB	102	printk(KERN_WARNING "mtdoops: erase of region [0x%llx, 0x%llx] on \"%s\" failed\n",
a15b124f AB	103	(unsigned long long)erase.addr,
2e386e4b	104	(unsigned long long)erase.len, mtddev);
4b23aff0 RP	105	return ret;
	106	}
	107
be95745f SK	108	/* Mark pages as unused */
	109	for (page = start_page; page < start_page + erase_pages; page++)
	110	mark_page_unused(cxt, page);
	111
4b23aff0 RP	112	return 0;
	113	}
	114
6ce0a856	115	static void mtdoops_inc_counter(struct mtdoops_context *cxt)
4b23aff0	116	{
4b23aff0	117	cxt->nextpage++;
ecd5b310	118	if (cxt->nextpage >= cxt->oops_pages)
4b23aff0 RP	119	cxt->nextpage = 0;
	120	cxt->nextcount++;
	121	if (cxt->nextcount == 0xffffffff)
	122	cxt->nextcount = 0;
	123
be95745f	124	if (page_is_used(cxt, cxt->nextpage)) {
6ce0a856 RP	125	schedule_work(&cxt->work_erase);
	126	return;
	127	}
4b23aff0	128
a15b124f AB	129	printk(KERN_DEBUG "mtdoops: ready %d, %d (no erase)\n",
a15b124f AB	130	cxt->nextpage, cxt->nextcount);
4b23aff0 RP	131	}
4b23aff0 RP	132
6ce0a856 RP	133	/* Scheduled work - when we can't proceed without erasing a block */
6ce0a856 RP	134	static void mtdoops_workfunc_erase(struct work_struct *work)
4b23aff0	135	{
6ce0a856 RP	136	struct mtdoops_context *cxt =
6ce0a856 RP	137	container_of(work, struct mtdoops_context, work_erase);
4b23aff0 RP	138	struct mtd_info *mtd = cxt->mtd;
	139	int i = 0, j, ret, mod;
	140
	141	/* We were unregistered */
	142	if (!mtd)
	143	return;
	144
9507b0c8	145	mod = (cxt->nextpage * record_size) % mtd->erasesize;
4b23aff0	146	if (mod != 0) {
9507b0c8	147	cxt->nextpage = cxt->nextpage + ((mtd->erasesize - mod) / record_size);
ecd5b310	148	if (cxt->nextpage >= cxt->oops_pages)
4b23aff0 RP	149	cxt->nextpage = 0;
	150	}
	151
9cb93fbb	152	while ((ret = mtd_block_isbad(mtd, cxt->nextpage * record_size)) > 0) {
4b23aff0	153	badblock:
9507b0c8 SK	154	printk(KERN_WARNING "mtdoops: bad block at %08lx\n",
9507b0c8 SK	155	cxt->nextpage * record_size);
4b23aff0	156	i++;
9507b0c8	157	cxt->nextpage = cxt->nextpage + (mtd->erasesize / record_size);
ecd5b310	158	if (cxt->nextpage >= cxt->oops_pages)
4b23aff0	159	cxt->nextpage = 0;
9507b0c8	160	if (i == cxt->oops_pages / (mtd->erasesize / record_size)) {
a15b124f	161	printk(KERN_ERR "mtdoops: all blocks bad!\n");
4b23aff0 RP	162	return;
	163	}
	164	}
	165
9cb93fbb BN	166	if (ret < 0) {
	167	printk(KERN_ERR "mtdoops: mtd_block_isbad failed, aborting\n");
	168	return;
	169	}
	170
4b23aff0	171	for (j = 0, ret = -1; (j < 3) && (ret < 0); j++)
9507b0c8	172	ret = mtdoops_erase_block(cxt, cxt->nextpage * record_size);
4b23aff0	173
2986bd2a	174	if (ret >= 0) {
a15b124f AB	175	printk(KERN_DEBUG "mtdoops: ready %d, %d\n",
a15b124f AB	176	cxt->nextpage, cxt->nextcount);
2986bd2a	177	return;
4b23aff0 RP	178	}
4b23aff0 RP	179
bb4a0986	180	if (ret == -EIO) {
5942ddbc	181	ret = mtd_block_markbad(mtd, cxt->nextpage * record_size);
bb4a0986	182	if (ret < 0 && ret != -EOPNOTSUPP) {
a15b124f	183	printk(KERN_ERR "mtdoops: block_markbad failed, aborting\n");
2986bd2a RP	184	return;
	185	}
	186	}
	187	goto badblock;
4b23aff0 RP	188	}
4b23aff0 RP	189
621e4f8e	190	static void mtdoops_write(struct mtdoops_context *cxt, int panic)
4b23aff0	191	{
6ce0a856 RP	192	struct mtd_info *mtd = cxt->mtd;
6ce0a856 RP	193	size_t retlen;
2e386e4b	194	u32 *hdr;
6ce0a856	195	int ret;
4b23aff0	196
2e386e4b SK	197	/* Add mtdoops header to the buffer */
	198	hdr = cxt->oops_buf;
	199	hdr[0] = cxt->nextcount;
	200	hdr[1] = MTDOOPS_KERNMSG_MAGIC;
6ce0a856	201
016c1291	202	if (panic) {
7ae79d7f AB	203	ret = mtd_panic_write(mtd, cxt->nextpage * record_size,
7ae79d7f AB	204	record_size, &retlen, cxt->oops_buf);
016c1291 AB	205	if (ret == -EOPNOTSUPP) {
	206	printk(KERN_ERR "mtdoops: Cannot write from panic without panic_write\n");
	207	return;
	208	}
	209	} else
eda95cbf AB	210	ret = mtd_write(mtd, cxt->nextpage * record_size,
eda95cbf AB	211	record_size, &retlen, cxt->oops_buf);
6ce0a856	212
9507b0c8 SK	213	if (retlen != record_size \|\| ret < 0)
	214	printk(KERN_ERR "mtdoops: write failure at %ld (%td of %ld written), error %d\n",
	215	cxt->nextpage * record_size, retlen, record_size, ret);
be95745f	216	mark_page_used(cxt, cxt->nextpage);
2e386e4b	217	memset(cxt->oops_buf, 0xff, record_size);
6ce0a856 RP	218
6ce0a856 RP	219	mtdoops_inc_counter(cxt);
621e4f8e RP	220	}
621e4f8e RP	221
621e4f8e RP	222	static void mtdoops_workfunc_write(struct work_struct *work)
	223	{
	224	struct mtdoops_context *cxt =
	225	container_of(work, struct mtdoops_context, work_write);
	226
	227	mtdoops_write(cxt, 0);
a15b124f	228	}
4b23aff0	229
6ce0a856	230	static void find_next_position(struct mtdoops_context *cxt)
4b23aff0 RP	231	{
4b23aff0 RP	232	struct mtd_info *mtd = cxt->mtd;
2986bd2a	233	int ret, page, maxpos = 0;
f0482ee3	234	u32 count[2], maxcount = 0xffffffff;
4b23aff0 RP	235	size_t retlen;
	236
	237	for (page = 0; page < cxt->oops_pages; page++) {
bb4a0986	238	if (mtd_block_isbad(mtd, page * record_size))
3538c563	239	continue;
be95745f SK	240	/* Assume the page is used */
be95745f SK	241	mark_page_used(cxt, page);
329ad399 AB	242	ret = mtd_read(mtd, page * record_size, MTDOOPS_HEADER_SIZE,
329ad399 AB	243	&retlen, (u_char *)&count[0]);
2e386e4b	244	if (retlen != MTDOOPS_HEADER_SIZE \|\|
d57f4054	245	(ret < 0 && !mtd_is_bitflip(ret))) {
2e386e4b SK	246	printk(KERN_ERR "mtdoops: read failure at %ld (%td of %d read), err %d\n",
	247	page * record_size, retlen,
	248	MTDOOPS_HEADER_SIZE, ret);
2986bd2a RP	249	continue;
	250	}
	251
be95745f SK	252	if (count[0] == 0xffffffff && count[1] == 0xffffffff)
be95745f SK	253	mark_page_unused(cxt, page);
cd409c61	254	if (count[0] == 0xffffffff \|\| count[1] != MTDOOPS_KERNMSG_MAGIC)
4b23aff0 RP	255	continue;
4b23aff0 RP	256	if (maxcount == 0xffffffff) {
f0482ee3	257	maxcount = count[0];
4b23aff0	258	maxpos = page;
a15b124f	259	} else if (count[0] < 0x40000000 && maxcount > 0xc0000000) {
f0482ee3	260	maxcount = count[0];
4b23aff0	261	maxpos = page;
a15b124f	262	} else if (count[0] > maxcount && count[0] < 0xc0000000) {
f0482ee3	263	maxcount = count[0];
4b23aff0	264	maxpos = page;
a15b124f AB	265	} else if (count[0] > maxcount && count[0] > 0xc0000000
a15b124f AB	266	&& maxcount > 0x80000000) {
f0482ee3	267	maxcount = count[0];
4b23aff0 RP	268	maxpos = page;
	269	}
	270	}
	271	if (maxcount == 0xffffffff) {
cd409c61 MC	272	cxt->nextpage = cxt->oops_pages - 1;
	273	cxt->nextcount = 0;
	274	}
	275	else {
	276	cxt->nextpage = maxpos;
	277	cxt->nextcount = maxcount;
4b23aff0	278	}
4b23aff0	279
6ce0a856	280	mtdoops_inc_counter(cxt);
4b23aff0 RP	281	}
4b23aff0 RP	282
2e386e4b	283	static void mtdoops_do_dump(struct kmsg_dumper *dumper,
e2ae715d	284	enum kmsg_dump_reason reason)
2e386e4b SK	285	{
	286	struct mtdoops_context *cxt = container_of(dumper,
	287	struct mtdoops_context, dump);
fc2d557c	288
2e386e4b SK	289	/* Only dump oopses if dump_oops is set */
	290	if (reason == KMSG_DUMP_OOPS && !dump_oops)
	291	return;
	292
e2ae715d KS	293	kmsg_dump_get_buffer(dumper, true, cxt->oops_buf + MTDOOPS_HEADER_SIZE,
e2ae715d KS	294	record_size - MTDOOPS_HEADER_SIZE, NULL);
2e386e4b SK	295
2e386e4b SK	296	/* Panics must be written immediately */
016c1291 AB	297	if (reason != KMSG_DUMP_OOPS)
016c1291 AB	298	mtdoops_write(cxt, 1);
2e386e4b SK	299
	300	/* For other cases, schedule work to write it "nicely" */
	301	schedule_work(&cxt->work_write);
	302	}
4b23aff0 RP	303
	304	static void mtdoops_notify_add(struct mtd_info *mtd)
	305	{
	306	struct mtdoops_context *cxt = &oops_cxt;
2e386e4b SK	307	u64 mtdoops_pages = div_u64(mtd->size, record_size);
2e386e4b SK	308	int err;
4b23aff0	309
2e386e4b	310	if (!strcmp(mtd->name, mtddev))
e2a0f25b AH	311	cxt->mtd_index = mtd->index;
e2a0f25b AH	312
a15b124f	313	if (mtd->index != cxt->mtd_index \|\| cxt->mtd_index < 0)
4b23aff0 RP	314	return;
4b23aff0 RP	315
a15b124f AB	316	if (mtd->size < mtd->erasesize * 2) {
	317	printk(KERN_ERR "mtdoops: MTD partition %d not big enough for mtdoops\n",
	318	mtd->index);
4b23aff0 RP	319	return;
4b23aff0 RP	320	}
9507b0c8	321	if (mtd->erasesize < record_size) {
a15b124f AB	322	printk(KERN_ERR "mtdoops: eraseblock size of MTD partition %d too small\n",
a15b124f AB	323	mtd->index);
79dcd8e9 RP	324	return;
79dcd8e9 RP	325	}
1114e3d0 SK	326	if (mtd->size > MTDOOPS_MAX_MTD_SIZE) {
	327	printk(KERN_ERR "mtdoops: mtd%d is too large (limit is %d MiB)\n",
	328	mtd->index, MTDOOPS_MAX_MTD_SIZE / 1024 / 1024);
	329	return;
	330	}
	331
be95745f	332	/* oops_page_used is a bit field */
42bc47b3 KC	333	cxt->oops_page_used =
	334	vmalloc(array_size(sizeof(unsigned long),
	335	DIV_ROUND_UP(mtdoops_pages,
	336	BITS_PER_LONG)));
be95745f	337	if (!cxt->oops_page_used) {
2e386e4b SK	338	printk(KERN_ERR "mtdoops: could not allocate page array\n");
	339	return;
	340	}
	341
e2ae715d	342	cxt->dump.max_reason = KMSG_DUMP_OOPS;
2e386e4b SK	343	cxt->dump.dump = mtdoops_do_dump;
	344	err = kmsg_dump_register(&cxt->dump);
	345	if (err) {
	346	printk(KERN_ERR "mtdoops: registering kmsg dumper failed, error %d\n", err);
	347	vfree(cxt->oops_page_used);
	348	cxt->oops_page_used = NULL;
be95745f SK	349	return;
be95745f SK	350	}
4b23aff0	351
1114e3d0	352	cxt->mtd = mtd;
9507b0c8	353	cxt->oops_pages = (int)mtd->size / record_size;
6ce0a856	354	find_next_position(cxt);
79dcd8e9	355	printk(KERN_INFO "mtdoops: Attached to MTD device %d\n", mtd->index);
4b23aff0 RP	356	}
	357
	358	static void mtdoops_notify_remove(struct mtd_info *mtd)
	359	{
	360	struct mtdoops_context *cxt = &oops_cxt;
	361
a15b124f	362	if (mtd->index != cxt->mtd_index \|\| cxt->mtd_index < 0)
4b23aff0 RP	363	return;
4b23aff0 RP	364
2e386e4b SK	365	if (kmsg_dump_unregister(&cxt->dump) < 0)
	366	printk(KERN_WARNING "mtdoops: could not unregister kmsg_dumper\n");
	367
4b23aff0	368	cxt->mtd = NULL;
43829731 TH	369	flush_work(&cxt->work_erase);
43829731 TH	370	flush_work(&cxt->work_write);
4b23aff0 RP	371	}
4b23aff0 RP	372
4b23aff0 RP	373
	374	static struct mtd_notifier mtdoops_notifier = {
	375	.add = mtdoops_notify_add,
	376	.remove = mtdoops_notify_remove,
	377	};
	378
2e386e4b	379	static int __init mtdoops_init(void)
4b23aff0 RP	380	{
4b23aff0 RP	381	struct mtdoops_context *cxt = &oops_cxt;
2e386e4b SK	382	int mtd_index;
2e386e4b SK	383	char *endp;
4b23aff0	384
2e386e4b SK	385	if (strlen(mtddev) == 0) {
	386	printk(KERN_ERR "mtdoops: mtd device (mtddev=name/number) must be supplied\n");
	387	return -EINVAL;
	388	}
9507b0c8 SK	389	if ((record_size & 4095) != 0) {
	390	printk(KERN_ERR "mtdoops: record_size must be a multiple of 4096\n");
	391	return -EINVAL;
	392	}
	393	if (record_size < 4096) {
	394	printk(KERN_ERR "mtdoops: record_size must be over 4096 bytes\n");
	395	return -EINVAL;
	396	}
2e386e4b SK	397
2e386e4b SK	398	/* Setup the MTD device to use */
4b23aff0	399	cxt->mtd_index = -1;
2e386e4b SK	400	mtd_index = simple_strtoul(mtddev, &endp, 0);
	401	if (*endp == '\0')
	402	cxt->mtd_index = mtd_index;
2e386e4b	403
9507b0c8	404	cxt->oops_buf = vmalloc(record_size);
4b23aff0	405	if (!cxt->oops_buf) {
a15b124f	406	printk(KERN_ERR "mtdoops: failed to allocate buffer workspace\n");
4b23aff0 RP	407	return -ENOMEM;
4b23aff0 RP	408	}
2e386e4b	409	memset(cxt->oops_buf, 0xff, record_size);
4b23aff0	410
6ce0a856 RP	411	INIT_WORK(&cxt->work_erase, mtdoops_workfunc_erase);
6ce0a856 RP	412	INIT_WORK(&cxt->work_write, mtdoops_workfunc_write);
4b23aff0	413
4b23aff0 RP	414	register_mtd_user(&mtdoops_notifier);
	415	return 0;
	416	}
	417
2e386e4b	418	static void __exit mtdoops_exit(void)
4b23aff0 RP	419	{
	420	struct mtdoops_context *cxt = &oops_cxt;
	421
	422	unregister_mtd_user(&mtdoops_notifier);
4b23aff0	423	vfree(cxt->oops_buf);
be95745f	424	vfree(cxt->oops_page_used);
4b23aff0 RP	425	}
	426
	427
2e386e4b SK	428	module_init(mtdoops_init);
2e386e4b SK	429	module_exit(mtdoops_exit);
4b23aff0 RP	430
	431	MODULE_LICENSE("GPL");
	432	MODULE_AUTHOR("Richard Purdie <[email protected]>");
	433	MODULE_DESCRIPTION("MTD Oops/Panic console logger/driver");