[mirror_ubuntu-hirsute-kernel.git] / drivers / mtd / mtdoops.c

// SPDX-License-Identifier: GPL-2.0-only
/*
 * MTD Oops/Panic logger
 *
 * Copyright © 2007 Nokia Corporation. All rights reserved.
 *
 * Author: Richard Purdie <rpurdie@openedhand.com>
 */

#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);

	if (reason != KMSG_DUMP_OOPS) {
		/* Panics must be written immediately */
		mtdoops_write(cxt, 1);
	} else {
		/* 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 <rpurdie@openedhand.com>");
MODULE_DESCRIPTION("MTD Oops/Panic console logger/driver");
Commit	Line	Data
2b27bdcc	1	// SPDX-License-Identifier: GPL-2.0-only
4b23aff0 RP	2	/*
	3	* MTD Oops/Panic logger
	4	*
a1452a37	5	* Copyright © 2007 Nokia Corporation. All rights reserved.
4b23aff0 RP	6	*
4b23aff0 RP	7	* Author: Richard Purdie <rpurdie@openedhand.com>
4b23aff0 RP	8	*/
	9
	10	#include <linux/kernel.h>
	11	#include <linux/module.h>
	12	#include <linux/console.h>
	13	#include <linux/vmalloc.h>
	14	#include <linux/workqueue.h>
	15	#include <linux/sched.h>
	16	#include <linux/wait.h>
621e4f8e	17	#include <linux/delay.h>
f9f7dd22	18	#include <linux/interrupt.h>
4b23aff0	19	#include <linux/mtd/mtd.h>
2e386e4b	20	#include <linux/kmsg_dump.h>
4b23aff0	21
1114e3d0 SK	22	/* Maximum MTD partition size */
	23	#define MTDOOPS_MAX_MTD_SIZE (8 * 1024 * 1024)
	24
f0482ee3	25	#define MTDOOPS_KERNMSG_MAGIC 0x5d005d00
2e386e4b	26	#define MTDOOPS_HEADER_SIZE 8
9507b0c8 SK	27
	28	static unsigned long record_size = 4096;
	29	module_param(record_size, ulong, 0400);
	30	MODULE_PARM_DESC(record_size,
	31	"record size for MTD OOPS pages in bytes (default 4096)");
4b23aff0	32
2e386e4b SK	33	static char mtddev[80];
	34	module_param_string(mtddev, mtddev, 80, 0400);
	35	MODULE_PARM_DESC(mtddev,
	36	"name or index number of the MTD device to use");
	37
	38	static int dump_oops = 1;
	39	module_param(dump_oops, int, 0600);
	40	MODULE_PARM_DESC(dump_oops,
	41	"set to 1 to dump oopses, 0 to only dump panics (default 1)");
	42
7903cbab	43	static struct mtdoops_context {
2e386e4b SK	44	struct kmsg_dumper dump;
2e386e4b SK	45
4b23aff0	46	int mtd_index;
6ce0a856 RP	47	struct work_struct work_erase;
6ce0a856 RP	48	struct work_struct work_write;
4b23aff0 RP	49	struct mtd_info *mtd;
	50	int oops_pages;
	51	int nextpage;
	52	int nextcount;
be95745f	53	unsigned long *oops_page_used;
4b23aff0 RP	54
4b23aff0 RP	55	void *oops_buf;
4b23aff0 RP	56	} oops_cxt;
4b23aff0 RP	57
be95745f SK	58	static void mark_page_used(struct mtdoops_context *cxt, int page)
	59	{
	60	set_bit(page, cxt->oops_page_used);
	61	}
	62
	63	static void mark_page_unused(struct mtdoops_context *cxt, int page)
	64	{
	65	clear_bit(page, cxt->oops_page_used);
	66	}
	67
	68	static int page_is_used(struct mtdoops_context *cxt, int page)
	69	{
	70	return test_bit(page, cxt->oops_page_used);
	71	}
	72
be95745f	73	static int mtdoops_erase_block(struct mtdoops_context *cxt, int offset)
4b23aff0	74	{
be95745f SK	75	struct mtd_info *mtd = cxt->mtd;
be95745f SK	76	u32 start_page_offset = mtd_div_by_eb(offset, mtd) * mtd->erasesize;
9507b0c8 SK	77	u32 start_page = start_page_offset / record_size;
9507b0c8 SK	78	u32 erase_pages = mtd->erasesize / record_size;
4b23aff0	79	struct erase_info erase;
4b23aff0	80	int ret;
be95745f	81	int page;
4b23aff0	82
4b23aff0	83	erase.addr = offset;
79dcd8e9	84	erase.len = mtd->erasesize;
4b23aff0	85
7e1f0dc0	86	ret = mtd_erase(mtd, &erase);
4b23aff0	87	if (ret) {
a15b124f AB	88	printk(KERN_WARNING "mtdoops: erase of region [0x%llx, 0x%llx] on \"%s\" failed\n",
a15b124f AB	89	(unsigned long long)erase.addr,
2e386e4b	90	(unsigned long long)erase.len, mtddev);
4b23aff0 RP	91	return ret;
	92	}
	93
be95745f SK	94	/* Mark pages as unused */
	95	for (page = start_page; page < start_page + erase_pages; page++)
	96	mark_page_unused(cxt, page);
	97
4b23aff0 RP	98	return 0;
	99	}
	100
6ce0a856	101	static void mtdoops_inc_counter(struct mtdoops_context *cxt)
4b23aff0	102	{
4b23aff0	103	cxt->nextpage++;
ecd5b310	104	if (cxt->nextpage >= cxt->oops_pages)
4b23aff0 RP	105	cxt->nextpage = 0;
	106	cxt->nextcount++;
	107	if (cxt->nextcount == 0xffffffff)
	108	cxt->nextcount = 0;
	109
be95745f	110	if (page_is_used(cxt, cxt->nextpage)) {
6ce0a856 RP	111	schedule_work(&cxt->work_erase);
	112	return;
	113	}
4b23aff0	114
a15b124f AB	115	printk(KERN_DEBUG "mtdoops: ready %d, %d (no erase)\n",
a15b124f AB	116	cxt->nextpage, cxt->nextcount);
4b23aff0 RP	117	}
4b23aff0 RP	118
6ce0a856 RP	119	/* Scheduled work - when we can't proceed without erasing a block */
6ce0a856 RP	120	static void mtdoops_workfunc_erase(struct work_struct *work)
4b23aff0	121	{
6ce0a856 RP	122	struct mtdoops_context *cxt =
6ce0a856 RP	123	container_of(work, struct mtdoops_context, work_erase);
4b23aff0 RP	124	struct mtd_info *mtd = cxt->mtd;
	125	int i = 0, j, ret, mod;
	126
	127	/* We were unregistered */
	128	if (!mtd)
	129	return;
	130
9507b0c8	131	mod = (cxt->nextpage * record_size) % mtd->erasesize;
4b23aff0	132	if (mod != 0) {
9507b0c8	133	cxt->nextpage = cxt->nextpage + ((mtd->erasesize - mod) / record_size);
ecd5b310	134	if (cxt->nextpage >= cxt->oops_pages)
4b23aff0 RP	135	cxt->nextpage = 0;
	136	}
	137
9cb93fbb	138	while ((ret = mtd_block_isbad(mtd, cxt->nextpage * record_size)) > 0) {
4b23aff0	139	badblock:
9507b0c8 SK	140	printk(KERN_WARNING "mtdoops: bad block at %08lx\n",
9507b0c8 SK	141	cxt->nextpage * record_size);
4b23aff0	142	i++;
9507b0c8	143	cxt->nextpage = cxt->nextpage + (mtd->erasesize / record_size);
ecd5b310	144	if (cxt->nextpage >= cxt->oops_pages)
4b23aff0	145	cxt->nextpage = 0;
9507b0c8	146	if (i == cxt->oops_pages / (mtd->erasesize / record_size)) {
a15b124f	147	printk(KERN_ERR "mtdoops: all blocks bad!\n");
4b23aff0 RP	148	return;
	149	}
	150	}
	151
9cb93fbb BN	152	if (ret < 0) {
	153	printk(KERN_ERR "mtdoops: mtd_block_isbad failed, aborting\n");
	154	return;
	155	}
	156
4b23aff0	157	for (j = 0, ret = -1; (j < 3) && (ret < 0); j++)
9507b0c8	158	ret = mtdoops_erase_block(cxt, cxt->nextpage * record_size);
4b23aff0	159
2986bd2a	160	if (ret >= 0) {
a15b124f AB	161	printk(KERN_DEBUG "mtdoops: ready %d, %d\n",
a15b124f AB	162	cxt->nextpage, cxt->nextcount);
2986bd2a	163	return;
4b23aff0 RP	164	}
4b23aff0 RP	165
bb4a0986	166	if (ret == -EIO) {
5942ddbc	167	ret = mtd_block_markbad(mtd, cxt->nextpage * record_size);
bb4a0986	168	if (ret < 0 && ret != -EOPNOTSUPP) {
a15b124f	169	printk(KERN_ERR "mtdoops: block_markbad failed, aborting\n");
2986bd2a RP	170	return;
	171	}
	172	}
	173	goto badblock;
4b23aff0 RP	174	}
4b23aff0 RP	175
621e4f8e	176	static void mtdoops_write(struct mtdoops_context *cxt, int panic)
4b23aff0	177	{
6ce0a856 RP	178	struct mtd_info *mtd = cxt->mtd;
6ce0a856 RP	179	size_t retlen;
2e386e4b	180	u32 *hdr;
6ce0a856	181	int ret;
4b23aff0	182
2e386e4b SK	183	/* Add mtdoops header to the buffer */
	184	hdr = cxt->oops_buf;
	185	hdr[0] = cxt->nextcount;
	186	hdr[1] = MTDOOPS_KERNMSG_MAGIC;
6ce0a856	187
016c1291	188	if (panic) {
7ae79d7f AB	189	ret = mtd_panic_write(mtd, cxt->nextpage * record_size,
7ae79d7f AB	190	record_size, &retlen, cxt->oops_buf);
016c1291 AB	191	if (ret == -EOPNOTSUPP) {
	192	printk(KERN_ERR "mtdoops: Cannot write from panic without panic_write\n");
	193	return;
	194	}
	195	} else
eda95cbf AB	196	ret = mtd_write(mtd, cxt->nextpage * record_size,
eda95cbf AB	197	record_size, &retlen, cxt->oops_buf);
6ce0a856	198
9507b0c8 SK	199	if (retlen != record_size \|\| ret < 0)
	200	printk(KERN_ERR "mtdoops: write failure at %ld (%td of %ld written), error %d\n",
	201	cxt->nextpage * record_size, retlen, record_size, ret);
be95745f	202	mark_page_used(cxt, cxt->nextpage);
2e386e4b	203	memset(cxt->oops_buf, 0xff, record_size);
6ce0a856 RP	204
6ce0a856 RP	205	mtdoops_inc_counter(cxt);
621e4f8e RP	206	}
621e4f8e RP	207
621e4f8e RP	208	static void mtdoops_workfunc_write(struct work_struct *work)
	209	{
	210	struct mtdoops_context *cxt =
	211	container_of(work, struct mtdoops_context, work_write);
	212
	213	mtdoops_write(cxt, 0);
a15b124f	214	}
4b23aff0	215
6ce0a856	216	static void find_next_position(struct mtdoops_context *cxt)
4b23aff0 RP	217	{
4b23aff0 RP	218	struct mtd_info *mtd = cxt->mtd;
2986bd2a	219	int ret, page, maxpos = 0;
f0482ee3	220	u32 count[2], maxcount = 0xffffffff;
4b23aff0 RP	221	size_t retlen;
	222
	223	for (page = 0; page < cxt->oops_pages; page++) {
bb4a0986	224	if (mtd_block_isbad(mtd, page * record_size))
3538c563	225	continue;
be95745f SK	226	/* Assume the page is used */
be95745f SK	227	mark_page_used(cxt, page);
329ad399 AB	228	ret = mtd_read(mtd, page * record_size, MTDOOPS_HEADER_SIZE,
329ad399 AB	229	&retlen, (u_char *)&count[0]);
2e386e4b	230	if (retlen != MTDOOPS_HEADER_SIZE \|\|
d57f4054	231	(ret < 0 && !mtd_is_bitflip(ret))) {
2e386e4b SK	232	printk(KERN_ERR "mtdoops: read failure at %ld (%td of %d read), err %d\n",
	233	page * record_size, retlen,
	234	MTDOOPS_HEADER_SIZE, ret);
2986bd2a RP	235	continue;
	236	}
	237
be95745f SK	238	if (count[0] == 0xffffffff && count[1] == 0xffffffff)
be95745f SK	239	mark_page_unused(cxt, page);
cd409c61	240	if (count[0] == 0xffffffff \|\| count[1] != MTDOOPS_KERNMSG_MAGIC)
4b23aff0 RP	241	continue;
4b23aff0 RP	242	if (maxcount == 0xffffffff) {
f0482ee3	243	maxcount = count[0];
4b23aff0	244	maxpos = page;
a15b124f	245	} else if (count[0] < 0x40000000 && maxcount > 0xc0000000) {
f0482ee3	246	maxcount = count[0];
4b23aff0	247	maxpos = page;
a15b124f	248	} else if (count[0] > maxcount && count[0] < 0xc0000000) {
f0482ee3	249	maxcount = count[0];
4b23aff0	250	maxpos = page;
a15b124f AB	251	} else if (count[0] > maxcount && count[0] > 0xc0000000
a15b124f AB	252	&& maxcount > 0x80000000) {
f0482ee3	253	maxcount = count[0];
4b23aff0 RP	254	maxpos = page;
	255	}
	256	}
	257	if (maxcount == 0xffffffff) {
cd409c61 MC	258	cxt->nextpage = cxt->oops_pages - 1;
	259	cxt->nextcount = 0;
	260	}
	261	else {
	262	cxt->nextpage = maxpos;
	263	cxt->nextcount = maxcount;
4b23aff0	264	}
4b23aff0	265
6ce0a856	266	mtdoops_inc_counter(cxt);
4b23aff0 RP	267	}
4b23aff0 RP	268
2e386e4b	269	static void mtdoops_do_dump(struct kmsg_dumper *dumper,
e2ae715d	270	enum kmsg_dump_reason reason)
2e386e4b SK	271	{
	272	struct mtdoops_context *cxt = container_of(dumper,
	273	struct mtdoops_context, dump);
fc2d557c	274
2e386e4b SK	275	/* Only dump oopses if dump_oops is set */
	276	if (reason == KMSG_DUMP_OOPS && !dump_oops)
	277	return;
	278
e2ae715d KS	279	kmsg_dump_get_buffer(dumper, true, cxt->oops_buf + MTDOOPS_HEADER_SIZE,
e2ae715d KS	280	record_size - MTDOOPS_HEADER_SIZE, NULL);
2e386e4b	281
c1cf1d57 MT	282	if (reason != KMSG_DUMP_OOPS) {
c1cf1d57 MT	283	/* Panics must be written immediately */
016c1291	284	mtdoops_write(cxt, 1);
c1cf1d57 MT	285	} else {
	286	/* For other cases, schedule work to write it "nicely" */
	287	schedule_work(&cxt->work_write);
	288	}
2e386e4b	289	}
4b23aff0 RP	290
	291	static void mtdoops_notify_add(struct mtd_info *mtd)
	292	{
	293	struct mtdoops_context *cxt = &oops_cxt;
2e386e4b SK	294	u64 mtdoops_pages = div_u64(mtd->size, record_size);
2e386e4b SK	295	int err;
4b23aff0	296
2e386e4b	297	if (!strcmp(mtd->name, mtddev))
e2a0f25b AH	298	cxt->mtd_index = mtd->index;
e2a0f25b AH	299
a15b124f	300	if (mtd->index != cxt->mtd_index \|\| cxt->mtd_index < 0)
4b23aff0 RP	301	return;
4b23aff0 RP	302
a15b124f AB	303	if (mtd->size < mtd->erasesize * 2) {
	304	printk(KERN_ERR "mtdoops: MTD partition %d not big enough for mtdoops\n",
	305	mtd->index);
4b23aff0 RP	306	return;
4b23aff0 RP	307	}
9507b0c8	308	if (mtd->erasesize < record_size) {
a15b124f AB	309	printk(KERN_ERR "mtdoops: eraseblock size of MTD partition %d too small\n",
a15b124f AB	310	mtd->index);
79dcd8e9 RP	311	return;
79dcd8e9 RP	312	}
1114e3d0 SK	313	if (mtd->size > MTDOOPS_MAX_MTD_SIZE) {
	314	printk(KERN_ERR "mtdoops: mtd%d is too large (limit is %d MiB)\n",
	315	mtd->index, MTDOOPS_MAX_MTD_SIZE / 1024 / 1024);
	316	return;
	317	}
	318
be95745f	319	/* oops_page_used is a bit field */
42bc47b3 KC	320	cxt->oops_page_used =
	321	vmalloc(array_size(sizeof(unsigned long),
	322	DIV_ROUND_UP(mtdoops_pages,
	323	BITS_PER_LONG)));
be95745f	324	if (!cxt->oops_page_used) {
2e386e4b SK	325	printk(KERN_ERR "mtdoops: could not allocate page array\n");
	326	return;
	327	}
	328
e2ae715d	329	cxt->dump.max_reason = KMSG_DUMP_OOPS;
2e386e4b SK	330	cxt->dump.dump = mtdoops_do_dump;
	331	err = kmsg_dump_register(&cxt->dump);
	332	if (err) {
	333	printk(KERN_ERR "mtdoops: registering kmsg dumper failed, error %d\n", err);
	334	vfree(cxt->oops_page_used);
	335	cxt->oops_page_used = NULL;
be95745f SK	336	return;
be95745f SK	337	}
4b23aff0	338
1114e3d0	339	cxt->mtd = mtd;
9507b0c8	340	cxt->oops_pages = (int)mtd->size / record_size;
6ce0a856	341	find_next_position(cxt);
79dcd8e9	342	printk(KERN_INFO "mtdoops: Attached to MTD device %d\n", mtd->index);
4b23aff0 RP	343	}
	344
	345	static void mtdoops_notify_remove(struct mtd_info *mtd)
	346	{
	347	struct mtdoops_context *cxt = &oops_cxt;
	348
a15b124f	349	if (mtd->index != cxt->mtd_index \|\| cxt->mtd_index < 0)
4b23aff0 RP	350	return;
4b23aff0 RP	351
2e386e4b SK	352	if (kmsg_dump_unregister(&cxt->dump) < 0)
	353	printk(KERN_WARNING "mtdoops: could not unregister kmsg_dumper\n");
	354
4b23aff0	355	cxt->mtd = NULL;
43829731 TH	356	flush_work(&cxt->work_erase);
43829731 TH	357	flush_work(&cxt->work_write);
4b23aff0 RP	358	}
4b23aff0 RP	359
4b23aff0 RP	360
	361	static struct mtd_notifier mtdoops_notifier = {
	362	.add = mtdoops_notify_add,
	363	.remove = mtdoops_notify_remove,
	364	};
	365
2e386e4b	366	static int __init mtdoops_init(void)
4b23aff0 RP	367	{
4b23aff0 RP	368	struct mtdoops_context *cxt = &oops_cxt;
2e386e4b SK	369	int mtd_index;
2e386e4b SK	370	char *endp;
4b23aff0	371
2e386e4b SK	372	if (strlen(mtddev) == 0) {
	373	printk(KERN_ERR "mtdoops: mtd device (mtddev=name/number) must be supplied\n");
	374	return -EINVAL;
	375	}
9507b0c8 SK	376	if ((record_size & 4095) != 0) {
	377	printk(KERN_ERR "mtdoops: record_size must be a multiple of 4096\n");
	378	return -EINVAL;
	379	}
	380	if (record_size < 4096) {
	381	printk(KERN_ERR "mtdoops: record_size must be over 4096 bytes\n");
	382	return -EINVAL;
	383	}
2e386e4b SK	384
2e386e4b SK	385	/* Setup the MTD device to use */
4b23aff0	386	cxt->mtd_index = -1;
2e386e4b SK	387	mtd_index = simple_strtoul(mtddev, &endp, 0);
	388	if (*endp == '\0')
	389	cxt->mtd_index = mtd_index;
2e386e4b	390
9507b0c8	391	cxt->oops_buf = vmalloc(record_size);
4b23aff0	392	if (!cxt->oops_buf) {
a15b124f	393	printk(KERN_ERR "mtdoops: failed to allocate buffer workspace\n");
4b23aff0 RP	394	return -ENOMEM;
4b23aff0 RP	395	}
2e386e4b	396	memset(cxt->oops_buf, 0xff, record_size);
4b23aff0	397
6ce0a856 RP	398	INIT_WORK(&cxt->work_erase, mtdoops_workfunc_erase);
6ce0a856 RP	399	INIT_WORK(&cxt->work_write, mtdoops_workfunc_write);
4b23aff0	400
4b23aff0 RP	401	register_mtd_user(&mtdoops_notifier);
	402	return 0;
	403	}
	404
2e386e4b	405	static void __exit mtdoops_exit(void)
4b23aff0 RP	406	{
	407	struct mtdoops_context *cxt = &oops_cxt;
	408
	409	unregister_mtd_user(&mtdoops_notifier);
4b23aff0	410	vfree(cxt->oops_buf);
be95745f	411	vfree(cxt->oops_page_used);
4b23aff0 RP	412	}
	413
	414
2e386e4b SK	415	module_init(mtdoops_init);
2e386e4b SK	416	module_exit(mtdoops_exit);
4b23aff0 RP	417
	418	MODULE_LICENSE("GPL");
	419	MODULE_AUTHOR("Richard Purdie <rpurdie@openedhand.com>");
	420	MODULE_DESCRIPTION("MTD Oops/Panic console logger/driver");