[linux-2.6-block.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)

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)");

#define MTDOOPS_KERNMSG_MAGIC 0x5d005d00

struct mtdoops_hdr {
	u32 seq;
	u32 magic;
} __packed;

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;

	unsigned long oops_buf_busy;
	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;
	struct mtdoops_hdr *hdr;
	int ret;

	if (test_and_set_bit(0, &cxt->oops_buf_busy))
		return;

	/* Add mtdoops header to the buffer */
	hdr = (struct mtdoops_hdr *)cxt->oops_buf;
	hdr->seq = cxt->nextcount;
	hdr->magic = 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");
			goto out;
		}
	} 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);
out:
	clear_bit(0, &cxt->oops_buf_busy);
}

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;
	struct mtdoops_hdr hdr;
	int ret, page, maxpos = 0;
	u32 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, sizeof(hdr),
			       &retlen, (u_char *)&hdr);
		if (retlen != sizeof(hdr) ||
				(ret < 0 && !mtd_is_bitflip(ret))) {
			printk(KERN_ERR "mtdoops: read failure at %ld (%zu of %zu read), err %d\n",
			       page * record_size, retlen, sizeof(hdr), ret);
			continue;
		}

		if (hdr.seq == 0xffffffff && hdr.magic == 0xffffffff)
			mark_page_unused(cxt, page);
		if (hdr.seq == 0xffffffff || hdr.magic != MTDOOPS_KERNMSG_MAGIC)
			continue;
		if (maxcount == 0xffffffff) {
			maxcount = hdr.seq;
			maxpos = page;
		} else if (hdr.seq < 0x40000000 && maxcount > 0xc0000000) {
			maxcount = hdr.seq;
			maxpos = page;
		} else if (hdr.seq > maxcount && hdr.seq < 0xc0000000) {
			maxcount = hdr.seq;
			maxpos = page;
		} else if (hdr.seq > maxcount && hdr.seq > 0xc0000000
					&& maxcount > 0x80000000) {
			maxcount = hdr.seq;
			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);
	struct kmsg_dump_iter iter;

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

	kmsg_dump_rewind(&iter);

	if (test_and_set_bit(0, &cxt->oops_buf_busy))
		return;
	kmsg_dump_get_buffer(&iter, true,
			     cxt->oops_buf + sizeof(struct mtdoops_hdr),
			     record_size - sizeof(struct mtdoops_hdr), NULL);
	clear_bit(0, &cxt->oops_buf_busy);

	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)
		return -ENOMEM;
	memset(cxt->oops_buf, 0xff, record_size);
	cxt->oops_buf_busy = 0;

	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
9507b0c8 SK	25	static unsigned long record_size = 4096;
	26	module_param(record_size, ulong, 0400);
	27	MODULE_PARM_DESC(record_size,
	28	"record size for MTD OOPS pages in bytes (default 4096)");
4b23aff0	29
2e386e4b SK	30	static char mtddev[80];
	31	module_param_string(mtddev, mtddev, 80, 0400);
	32	MODULE_PARM_DESC(mtddev,
	33	"name or index number of the MTD device to use");
	34
	35	static int dump_oops = 1;
	36	module_param(dump_oops, int, 0600);
	37	MODULE_PARM_DESC(dump_oops,
	38	"set to 1 to dump oopses, 0 to only dump panics (default 1)");
	39
0bd359ee JME	40	#define MTDOOPS_KERNMSG_MAGIC 0x5d005d00
	41
	42	struct mtdoops_hdr {
	43	u32 seq;
	44	u32 magic;
	45	} __packed;
	46
7903cbab	47	static struct mtdoops_context {
2e386e4b SK	48	struct kmsg_dumper dump;
2e386e4b SK	49
4b23aff0	50	int mtd_index;
6ce0a856 RP	51	struct work_struct work_erase;
6ce0a856 RP	52	struct work_struct work_write;
4b23aff0 RP	53	struct mtd_info *mtd;
	54	int oops_pages;
	55	int nextpage;
	56	int nextcount;
be95745f	57	unsigned long *oops_page_used;
4b23aff0	58
40ddbbac	59	unsigned long oops_buf_busy;
4b23aff0	60	void *oops_buf;
4b23aff0 RP	61	} oops_cxt;
4b23aff0 RP	62
be95745f SK	63	static void mark_page_used(struct mtdoops_context *cxt, int page)
	64	{
	65	set_bit(page, cxt->oops_page_used);
	66	}
	67
	68	static void mark_page_unused(struct mtdoops_context *cxt, int page)
	69	{
	70	clear_bit(page, cxt->oops_page_used);
	71	}
	72
	73	static int page_is_used(struct mtdoops_context *cxt, int page)
	74	{
	75	return test_bit(page, cxt->oops_page_used);
	76	}
	77
be95745f	78	static int mtdoops_erase_block(struct mtdoops_context *cxt, int offset)
4b23aff0	79	{
be95745f SK	80	struct mtd_info *mtd = cxt->mtd;
be95745f SK	81	u32 start_page_offset = mtd_div_by_eb(offset, mtd) * mtd->erasesize;
9507b0c8 SK	82	u32 start_page = start_page_offset / record_size;
9507b0c8 SK	83	u32 erase_pages = mtd->erasesize / record_size;
4b23aff0	84	struct erase_info erase;
4b23aff0	85	int ret;
be95745f	86	int page;
4b23aff0	87
4b23aff0	88	erase.addr = offset;
79dcd8e9	89	erase.len = mtd->erasesize;
4b23aff0	90
7e1f0dc0	91	ret = mtd_erase(mtd, &erase);
4b23aff0	92	if (ret) {
a15b124f AB	93	printk(KERN_WARNING "mtdoops: erase of region [0x%llx, 0x%llx] on \"%s\" failed\n",
a15b124f AB	94	(unsigned long long)erase.addr,
2e386e4b	95	(unsigned long long)erase.len, mtddev);
4b23aff0 RP	96	return ret;
	97	}
	98
be95745f SK	99	/* Mark pages as unused */
	100	for (page = start_page; page < start_page + erase_pages; page++)
	101	mark_page_unused(cxt, page);
	102
4b23aff0 RP	103	return 0;
	104	}
	105
6ce0a856	106	static void mtdoops_inc_counter(struct mtdoops_context *cxt)
4b23aff0	107	{
4b23aff0	108	cxt->nextpage++;
ecd5b310	109	if (cxt->nextpage >= cxt->oops_pages)
4b23aff0 RP	110	cxt->nextpage = 0;
	111	cxt->nextcount++;
	112	if (cxt->nextcount == 0xffffffff)
	113	cxt->nextcount = 0;
	114
be95745f	115	if (page_is_used(cxt, cxt->nextpage)) {
6ce0a856 RP	116	schedule_work(&cxt->work_erase);
	117	return;
	118	}
4b23aff0	119
a15b124f AB	120	printk(KERN_DEBUG "mtdoops: ready %d, %d (no erase)\n",
a15b124f AB	121	cxt->nextpage, cxt->nextcount);
4b23aff0 RP	122	}
4b23aff0 RP	123
6ce0a856 RP	124	/* Scheduled work - when we can't proceed without erasing a block */
6ce0a856 RP	125	static void mtdoops_workfunc_erase(struct work_struct *work)
4b23aff0	126	{
6ce0a856 RP	127	struct mtdoops_context *cxt =
6ce0a856 RP	128	container_of(work, struct mtdoops_context, work_erase);
4b23aff0 RP	129	struct mtd_info *mtd = cxt->mtd;
	130	int i = 0, j, ret, mod;
	131
	132	/* We were unregistered */
	133	if (!mtd)
	134	return;
	135
9507b0c8	136	mod = (cxt->nextpage * record_size) % mtd->erasesize;
4b23aff0	137	if (mod != 0) {
9507b0c8	138	cxt->nextpage = cxt->nextpage + ((mtd->erasesize - mod) / record_size);
ecd5b310	139	if (cxt->nextpage >= cxt->oops_pages)
4b23aff0 RP	140	cxt->nextpage = 0;
	141	}
	142
9cb93fbb	143	while ((ret = mtd_block_isbad(mtd, cxt->nextpage * record_size)) > 0) {
4b23aff0	144	badblock:
9507b0c8 SK	145	printk(KERN_WARNING "mtdoops: bad block at %08lx\n",
9507b0c8 SK	146	cxt->nextpage * record_size);
4b23aff0	147	i++;
9507b0c8	148	cxt->nextpage = cxt->nextpage + (mtd->erasesize / record_size);
ecd5b310	149	if (cxt->nextpage >= cxt->oops_pages)
4b23aff0	150	cxt->nextpage = 0;
9507b0c8	151	if (i == cxt->oops_pages / (mtd->erasesize / record_size)) {
a15b124f	152	printk(KERN_ERR "mtdoops: all blocks bad!\n");
4b23aff0 RP	153	return;
	154	}
	155	}
	156
9cb93fbb BN	157	if (ret < 0) {
	158	printk(KERN_ERR "mtdoops: mtd_block_isbad failed, aborting\n");
	159	return;
	160	}
	161
4b23aff0	162	for (j = 0, ret = -1; (j < 3) && (ret < 0); j++)
9507b0c8	163	ret = mtdoops_erase_block(cxt, cxt->nextpage * record_size);
4b23aff0	164
2986bd2a	165	if (ret >= 0) {
a15b124f AB	166	printk(KERN_DEBUG "mtdoops: ready %d, %d\n",
a15b124f AB	167	cxt->nextpage, cxt->nextcount);
2986bd2a	168	return;
4b23aff0 RP	169	}
4b23aff0 RP	170
bb4a0986	171	if (ret == -EIO) {
5942ddbc	172	ret = mtd_block_markbad(mtd, cxt->nextpage * record_size);
bb4a0986	173	if (ret < 0 && ret != -EOPNOTSUPP) {
a15b124f	174	printk(KERN_ERR "mtdoops: block_markbad failed, aborting\n");
2986bd2a RP	175	return;
	176	}
	177	}
	178	goto badblock;
4b23aff0 RP	179	}
4b23aff0 RP	180
621e4f8e	181	static void mtdoops_write(struct mtdoops_context *cxt, int panic)
4b23aff0	182	{
6ce0a856 RP	183	struct mtd_info *mtd = cxt->mtd;
6ce0a856 RP	184	size_t retlen;
0bd359ee	185	struct mtdoops_hdr *hdr;
6ce0a856	186	int ret;
4b23aff0	187
40ddbbac JO	188	if (test_and_set_bit(0, &cxt->oops_buf_busy))
	189	return;
	190
2e386e4b	191	/* Add mtdoops header to the buffer */
0bd359ee JME	192	hdr = (struct mtdoops_hdr *)cxt->oops_buf;
	193	hdr->seq = cxt->nextcount;
	194	hdr->magic = MTDOOPS_KERNMSG_MAGIC;
6ce0a856	195
016c1291	196	if (panic) {
7ae79d7f AB	197	ret = mtd_panic_write(mtd, cxt->nextpage * record_size,
7ae79d7f AB	198	record_size, &retlen, cxt->oops_buf);
016c1291 AB	199	if (ret == -EOPNOTSUPP) {
016c1291 AB	200	printk(KERN_ERR "mtdoops: Cannot write from panic without panic_write\n");
40ddbbac	201	goto out;
016c1291 AB	202	}
016c1291 AB	203	} else
eda95cbf AB	204	ret = mtd_write(mtd, cxt->nextpage * record_size,
eda95cbf AB	205	record_size, &retlen, cxt->oops_buf);
6ce0a856	206
9507b0c8 SK	207	if (retlen != record_size \|\| ret < 0)
	208	printk(KERN_ERR "mtdoops: write failure at %ld (%td of %ld written), error %d\n",
	209	cxt->nextpage * record_size, retlen, record_size, ret);
be95745f	210	mark_page_used(cxt, cxt->nextpage);
2e386e4b	211	memset(cxt->oops_buf, 0xff, record_size);
6ce0a856 RP	212
6ce0a856 RP	213	mtdoops_inc_counter(cxt);
40ddbbac JO	214	out:
40ddbbac JO	215	clear_bit(0, &cxt->oops_buf_busy);
621e4f8e RP	216	}
621e4f8e RP	217
621e4f8e RP	218	static void mtdoops_workfunc_write(struct work_struct *work)
	219	{
	220	struct mtdoops_context *cxt =
	221	container_of(work, struct mtdoops_context, work_write);
	222
	223	mtdoops_write(cxt, 0);
a15b124f	224	}
4b23aff0	225
6ce0a856	226	static void find_next_position(struct mtdoops_context *cxt)
4b23aff0 RP	227	{
4b23aff0 RP	228	struct mtd_info *mtd = cxt->mtd;
0bd359ee	229	struct mtdoops_hdr hdr;
2986bd2a	230	int ret, page, maxpos = 0;
0bd359ee	231	u32 maxcount = 0xffffffff;
4b23aff0 RP	232	size_t retlen;
	233
	234	for (page = 0; page < cxt->oops_pages; page++) {
bb4a0986	235	if (mtd_block_isbad(mtd, page * record_size))
3538c563	236	continue;
be95745f SK	237	/* Assume the page is used */
be95745f SK	238	mark_page_used(cxt, page);
0bd359ee JME	239	ret = mtd_read(mtd, page * record_size, sizeof(hdr),
	240	&retlen, (u_char *)&hdr);
	241	if (retlen != sizeof(hdr) \|\|
d57f4054	242	(ret < 0 && !mtd_is_bitflip(ret))) {
0bd359ee JME	243	printk(KERN_ERR "mtdoops: read failure at %ld (%zu of %zu read), err %d\n",
0bd359ee JME	244	page * record_size, retlen, sizeof(hdr), ret);
2986bd2a RP	245	continue;
	246	}
	247
0bd359ee	248	if (hdr.seq == 0xffffffff && hdr.magic == 0xffffffff)
be95745f	249	mark_page_unused(cxt, page);
0bd359ee	250	if (hdr.seq == 0xffffffff \|\| hdr.magic != MTDOOPS_KERNMSG_MAGIC)
4b23aff0 RP	251	continue;
4b23aff0 RP	252	if (maxcount == 0xffffffff) {
0bd359ee	253	maxcount = hdr.seq;
4b23aff0	254	maxpos = page;
0bd359ee JME	255	} else if (hdr.seq < 0x40000000 && maxcount > 0xc0000000) {
0bd359ee JME	256	maxcount = hdr.seq;
4b23aff0	257	maxpos = page;
0bd359ee JME	258	} else if (hdr.seq > maxcount && hdr.seq < 0xc0000000) {
0bd359ee JME	259	maxcount = hdr.seq;
4b23aff0	260	maxpos = page;
0bd359ee	261	} else if (hdr.seq > maxcount && hdr.seq > 0xc0000000
a15b124f	262	&& maxcount > 0x80000000) {
0bd359ee	263	maxcount = hdr.seq;
4b23aff0 RP	264	maxpos = page;
	265	}
	266	}
	267	if (maxcount == 0xffffffff) {
cd409c61 MC	268	cxt->nextpage = cxt->oops_pages - 1;
	269	cxt->nextcount = 0;
	270	}
	271	else {
	272	cxt->nextpage = maxpos;
	273	cxt->nextcount = maxcount;
4b23aff0	274	}
4b23aff0	275
6ce0a856	276	mtdoops_inc_counter(cxt);
4b23aff0 RP	277	}
4b23aff0 RP	278
2e386e4b	279	static void mtdoops_do_dump(struct kmsg_dumper *dumper,
e2ae715d	280	enum kmsg_dump_reason reason)
2e386e4b SK	281	{
	282	struct mtdoops_context *cxt = container_of(dumper,
	283	struct mtdoops_context, dump);
f9f3f02d	284	struct kmsg_dump_iter iter;
fc2d557c	285
2e386e4b SK	286	/* Only dump oopses if dump_oops is set */
	287	if (reason == KMSG_DUMP_OOPS && !dump_oops)
	288	return;
	289
f9f3f02d JO	290	kmsg_dump_rewind(&iter);
f9f3f02d JO	291
40ddbbac JO	292	if (test_and_set_bit(0, &cxt->oops_buf_busy))
40ddbbac JO	293	return;
0bd359ee JME	294	kmsg_dump_get_buffer(&iter, true,
	295	cxt->oops_buf + sizeof(struct mtdoops_hdr),
	296	record_size - sizeof(struct mtdoops_hdr), NULL);
40ddbbac	297	clear_bit(0, &cxt->oops_buf_busy);
2e386e4b	298
c1cf1d57 MT	299	if (reason != KMSG_DUMP_OOPS) {
c1cf1d57 MT	300	/* Panics must be written immediately */
016c1291	301	mtdoops_write(cxt, 1);
c1cf1d57 MT	302	} else {
	303	/* For other cases, schedule work to write it "nicely" */
	304	schedule_work(&cxt->work_write);
	305	}
2e386e4b	306	}
4b23aff0 RP	307
	308	static void mtdoops_notify_add(struct mtd_info *mtd)
	309	{
	310	struct mtdoops_context *cxt = &oops_cxt;
2e386e4b SK	311	u64 mtdoops_pages = div_u64(mtd->size, record_size);
2e386e4b SK	312	int err;
4b23aff0	313
2e386e4b	314	if (!strcmp(mtd->name, mtddev))
e2a0f25b AH	315	cxt->mtd_index = mtd->index;
e2a0f25b AH	316
a15b124f	317	if (mtd->index != cxt->mtd_index \|\| cxt->mtd_index < 0)
4b23aff0 RP	318	return;
4b23aff0 RP	319
a15b124f AB	320	if (mtd->size < mtd->erasesize * 2) {
	321	printk(KERN_ERR "mtdoops: MTD partition %d not big enough for mtdoops\n",
	322	mtd->index);
4b23aff0 RP	323	return;
4b23aff0 RP	324	}
9507b0c8	325	if (mtd->erasesize < record_size) {
a15b124f AB	326	printk(KERN_ERR "mtdoops: eraseblock size of MTD partition %d too small\n",
a15b124f AB	327	mtd->index);
79dcd8e9 RP	328	return;
79dcd8e9 RP	329	}
1114e3d0 SK	330	if (mtd->size > MTDOOPS_MAX_MTD_SIZE) {
	331	printk(KERN_ERR "mtdoops: mtd%d is too large (limit is %d MiB)\n",
	332	mtd->index, MTDOOPS_MAX_MTD_SIZE / 1024 / 1024);
	333	return;
	334	}
	335
be95745f	336	/* oops_page_used is a bit field */
42bc47b3 KC	337	cxt->oops_page_used =
	338	vmalloc(array_size(sizeof(unsigned long),
	339	DIV_ROUND_UP(mtdoops_pages,
	340	BITS_PER_LONG)));
be95745f	341	if (!cxt->oops_page_used) {
2e386e4b SK	342	printk(KERN_ERR "mtdoops: could not allocate page array\n");
	343	return;
	344	}
	345
e2ae715d	346	cxt->dump.max_reason = KMSG_DUMP_OOPS;
2e386e4b SK	347	cxt->dump.dump = mtdoops_do_dump;
	348	err = kmsg_dump_register(&cxt->dump);
	349	if (err) {
	350	printk(KERN_ERR "mtdoops: registering kmsg dumper failed, error %d\n", err);
	351	vfree(cxt->oops_page_used);
	352	cxt->oops_page_used = NULL;
be95745f SK	353	return;
be95745f SK	354	}
4b23aff0	355
1114e3d0	356	cxt->mtd = mtd;
9507b0c8	357	cxt->oops_pages = (int)mtd->size / record_size;
6ce0a856	358	find_next_position(cxt);
79dcd8e9	359	printk(KERN_INFO "mtdoops: Attached to MTD device %d\n", mtd->index);
4b23aff0 RP	360	}
	361
	362	static void mtdoops_notify_remove(struct mtd_info *mtd)
	363	{
	364	struct mtdoops_context *cxt = &oops_cxt;
	365
a15b124f	366	if (mtd->index != cxt->mtd_index \|\| cxt->mtd_index < 0)
4b23aff0 RP	367	return;
4b23aff0 RP	368
2e386e4b SK	369	if (kmsg_dump_unregister(&cxt->dump) < 0)
	370	printk(KERN_WARNING "mtdoops: could not unregister kmsg_dumper\n");
	371
4b23aff0	372	cxt->mtd = NULL;
43829731 TH	373	flush_work(&cxt->work_erase);
43829731 TH	374	flush_work(&cxt->work_write);
4b23aff0 RP	375	}
4b23aff0 RP	376
4b23aff0 RP	377
	378	static struct mtd_notifier mtdoops_notifier = {
	379	.add = mtdoops_notify_add,
	380	.remove = mtdoops_notify_remove,
	381	};
	382
2e386e4b	383	static int __init mtdoops_init(void)
4b23aff0 RP	384	{
4b23aff0 RP	385	struct mtdoops_context *cxt = &oops_cxt;
2e386e4b SK	386	int mtd_index;
2e386e4b SK	387	char *endp;
4b23aff0	388
2e386e4b SK	389	if (strlen(mtddev) == 0) {
	390	printk(KERN_ERR "mtdoops: mtd device (mtddev=name/number) must be supplied\n");
	391	return -EINVAL;
	392	}
9507b0c8 SK	393	if ((record_size & 4095) != 0) {
	394	printk(KERN_ERR "mtdoops: record_size must be a multiple of 4096\n");
	395	return -EINVAL;
	396	}
	397	if (record_size < 4096) {
	398	printk(KERN_ERR "mtdoops: record_size must be over 4096 bytes\n");
	399	return -EINVAL;
	400	}
2e386e4b SK	401
2e386e4b SK	402	/* Setup the MTD device to use */
4b23aff0	403	cxt->mtd_index = -1;
2e386e4b SK	404	mtd_index = simple_strtoul(mtddev, &endp, 0);
	405	if (*endp == '\0')
	406	cxt->mtd_index = mtd_index;
2e386e4b	407
9507b0c8	408	cxt->oops_buf = vmalloc(record_size);
313ea21a	409	if (!cxt->oops_buf)
4b23aff0	410	return -ENOMEM;
2e386e4b	411	memset(cxt->oops_buf, 0xff, record_size);
40ddbbac	412	cxt->oops_buf_busy = 0;
4b23aff0	413
6ce0a856 RP	414	INIT_WORK(&cxt->work_erase, mtdoops_workfunc_erase);
6ce0a856 RP	415	INIT_WORK(&cxt->work_write, mtdoops_workfunc_write);
4b23aff0	416
4b23aff0 RP	417	register_mtd_user(&mtdoops_notifier);
	418	return 0;
	419	}
	420
2e386e4b	421	static void __exit mtdoops_exit(void)
4b23aff0 RP	422	{
	423	struct mtdoops_context *cxt = &oops_cxt;
	424
	425	unregister_mtd_user(&mtdoops_notifier);
4b23aff0	426	vfree(cxt->oops_buf);
be95745f	427	vfree(cxt->oops_page_used);
4b23aff0 RP	428	}
	429
	430
2e386e4b SK	431	module_init(mtdoops_init);
2e386e4b SK	432	module_exit(mtdoops_exit);
4b23aff0 RP	433
	434	MODULE_LICENSE("GPL");
	435	MODULE_AUTHOR("Richard Purdie <rpurdie@openedhand.com>");
	436	MODULE_DESCRIPTION("MTD Oops/Panic console logger/driver");