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

/*
 * MTD Oops/Panic logger
 *
 * Copyright (C) 2007 Nokia Corporation. All rights reserved.
 *
 * Author: Richard Purdie <rpurdie@openedhand.com>
 *
 * 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/mtd/mtd.h>

#define OOPS_PAGE_SIZE 4096

struct mtdoops_context {
	int mtd_index;
	struct work_struct work_erase;
	struct work_struct work_write;
	struct mtd_info *mtd;
	int oops_pages;
	int nextpage;
	int nextcount;

	void *oops_buf;
	int ready;
	int writecount;
} oops_cxt;

static void mtdoops_erase_callback(struct erase_info *done)
{
	wait_queue_head_t *wait_q = (wait_queue_head_t *)done->priv;
	wake_up(wait_q);
}

static int mtdoops_erase_block(struct mtd_info *mtd, int offset)
{
	struct erase_info erase;
	DECLARE_WAITQUEUE(wait, current);
	wait_queue_head_t wait_q;
	int ret;

	init_waitqueue_head(&wait_q);
	erase.mtd = mtd;
	erase.callback = mtdoops_erase_callback;
	erase.addr = offset;
	if (mtd->erasesize < OOPS_PAGE_SIZE)
		erase.len = OOPS_PAGE_SIZE;
	else
		erase.len = mtd->erasesize;
	erase.priv = (u_long)&wait_q;

	set_current_state(TASK_INTERRUPTIBLE);
	add_wait_queue(&wait_q, &wait);

	ret = mtd->erase(mtd, &erase);
	if (ret) {
		set_current_state(TASK_RUNNING);
		remove_wait_queue(&wait_q, &wait);
		printk (KERN_WARNING "mtdoops: erase of region [0x%x, 0x%x] "
				     "on \"%s\" failed\n",
			erase.addr, erase.len, mtd->name);
		return ret;
	}

	schedule();  /* Wait for erase to finish. */
	remove_wait_queue(&wait_q, &wait);

	return 0;
}

static void mtdoops_inc_counter(struct mtdoops_context *cxt)
{
	struct mtd_info *mtd = cxt->mtd;
	size_t retlen;
	u32 count;
	int ret;

	cxt->nextpage++;
	if (cxt->nextpage > cxt->oops_pages)
		cxt->nextpage = 0;
	cxt->nextcount++;
	if (cxt->nextcount == 0xffffffff)
		cxt->nextcount = 0;

	ret = mtd->read(mtd, cxt->nextpage * OOPS_PAGE_SIZE, 4,
			&retlen, (u_char *) &count);
	if ((retlen != 4) || ((ret < 0) && (ret != -EUCLEAN))) {
		printk(KERN_ERR "mtdoops: Read failure at %d (%td of 4 read)"
				", err %d.\n", cxt->nextpage * OOPS_PAGE_SIZE,
				retlen, ret);
		schedule_work(&cxt->work_erase);
		return;
	}

	/* See if we need to erase the next block */
	if (count != 0xffffffff) {
		schedule_work(&cxt->work_erase);
		return;
	}

	printk(KERN_DEBUG "mtdoops: Ready %d, %d (no erase)\n",
			cxt->nextpage, cxt->nextcount);
	cxt->ready = 1;
}

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

	while (mtd->block_isbad) {
		ret = mtd->block_isbad(mtd, cxt->nextpage * OOPS_PAGE_SIZE);
		if (!ret)
			break;
		if (ret < 0) {
			printk(KERN_ERR "mtdoops: block_isbad failed, aborting.\n");
			return;
		}
badblock:
		printk(KERN_WARNING "mtdoops: Bad block at %08x\n",
				cxt->nextpage * OOPS_PAGE_SIZE);
		i++;
		cxt->nextpage = cxt->nextpage + (mtd->erasesize / OOPS_PAGE_SIZE);
		if (cxt->nextpage > cxt->oops_pages)
			cxt->nextpage = 0;
		if (i == (cxt->oops_pages / (mtd->erasesize / OOPS_PAGE_SIZE))) {
			printk(KERN_ERR "mtdoops: All blocks bad!\n");
			return;
		}
	}

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

	if (ret >= 0) {
		printk(KERN_DEBUG "mtdoops: Ready %d, %d \n", cxt->nextpage, cxt->nextcount);
		cxt->ready = 1;
		return;
	}

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

static void mtdoops_workfunc_write(struct work_struct *work)
{
	struct mtdoops_context *cxt =
			container_of(work, struct mtdoops_context, work_write);
	struct mtd_info *mtd = cxt->mtd;
	size_t retlen;
	int ret;

	if (cxt->writecount < OOPS_PAGE_SIZE)
		memset(cxt->oops_buf + cxt->writecount, 0xff,
					OOPS_PAGE_SIZE - cxt->writecount);

	ret = mtd->write(mtd, cxt->nextpage * OOPS_PAGE_SIZE,
					OOPS_PAGE_SIZE, &retlen, cxt->oops_buf);

	cxt->writecount = 0;

	if ((retlen != OOPS_PAGE_SIZE) || (ret < 0))
		printk(KERN_ERR "mtdoops: Write failure at %d (%td of %d written), err %d.\n",
			cxt->nextpage * OOPS_PAGE_SIZE, retlen,	OOPS_PAGE_SIZE, ret);

	mtdoops_inc_counter(cxt);
}					

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

	for (page = 0; page < cxt->oops_pages; page++) {
		ret = mtd->read(mtd, page * OOPS_PAGE_SIZE, 4, &retlen, (u_char *) &count);
		if ((retlen != 4) || ((ret < 0) && (ret != -EUCLEAN))) {
			printk(KERN_ERR "mtdoops: Read failure at %d (%td of 4 read)"
				", err %d.\n", page * OOPS_PAGE_SIZE, retlen, ret);
			continue;
		}

		if (count == 0xffffffff)
			continue;
		if (maxcount == 0xffffffff) {
			maxcount = count;
			maxpos = page;
		} else if ((count < 0x40000000) && (maxcount > 0xc0000000)) {
			maxcount = count;
			maxpos = page;
		} else if ((count > maxcount) && (count < 0xc0000000)) {
			maxcount = count;
			maxpos = page;
		} else if ((count > maxcount) && (count > 0xc0000000)
					&& (maxcount > 0x80000000)) {
			maxcount = count;
			maxpos = page;
		}
	}
	if (maxcount == 0xffffffff) {
		cxt->nextpage = 0;
		cxt->nextcount = 1;
		cxt->ready = 1;
		printk(KERN_DEBUG "mtdoops: Ready %d, %d (first init)\n",
				cxt->nextpage, cxt->nextcount);
		return;
	}

	cxt->nextpage = maxpos;
	cxt->nextcount = maxcount;

	mtdoops_inc_counter(cxt);
}


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

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

	if (mtd->size < (mtd->erasesize * 2)) {
		printk(KERN_ERR "MTD partition %d not big enough for mtdoops\n",
				mtd->index);
		return;
	}

	cxt->mtd = mtd;
	cxt->oops_pages = mtd->size / OOPS_PAGE_SIZE;

	find_next_position(cxt);

	printk(KERN_DEBUG "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;

	cxt->mtd = NULL;
	flush_scheduled_work();
}

static void mtdoops_console_sync(void)
{
	struct mtdoops_context *cxt = &oops_cxt;
	struct mtd_info *mtd = cxt->mtd;

	if (!cxt->ready || !mtd || cxt->writecount == 0)
		return;

	cxt->ready = 0;

	schedule_work(&cxt->work_write);
}

static void
mtdoops_console_write(struct console *co, const char *s, unsigned int count)
{
	struct mtdoops_context *cxt = co->data;
	struct mtd_info *mtd = cxt->mtd;

	if (!oops_in_progress) {
		mtdoops_console_sync();
		return;
	}

	if (!cxt->ready || !mtd)
		return;

	if (cxt->writecount == 0) {
		u32 *stamp = cxt->oops_buf;
		*stamp = cxt->nextcount;
		cxt->writecount = 4;
	}

	if ((count + cxt->writecount) > OOPS_PAGE_SIZE)
		count = OOPS_PAGE_SIZE - cxt->writecount;

	memcpy(cxt->oops_buf + cxt->writecount, s, count);
	cxt->writecount += count;
}

static int __init mtdoops_console_setup(struct console *co, char *options)
{
	struct mtdoops_context *cxt = co->data;

	if (cxt->mtd_index != -1)
		return -EBUSY;
	if (co->index == -1)
		return -EINVAL;

	cxt->mtd_index = co->index;
	return 0;
}

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

static struct console mtdoops_console = {
	.name		= "ttyMTD",
	.write		= mtdoops_console_write,
	.setup		= mtdoops_console_setup,
	.unblank	= mtdoops_console_sync,
	.flags		= CON_PRINTBUFFER,
	.index		= -1,
	.data		= &oops_cxt,
};

static int __init mtdoops_console_init(void)
{
	struct mtdoops_context *cxt = &oops_cxt;

	cxt->mtd_index = -1;
	cxt->oops_buf = vmalloc(OOPS_PAGE_SIZE);

	if (!cxt->oops_buf) {
		printk(KERN_ERR "Failed to allocate oops buffer workspace\n");
		return -ENOMEM;
	}

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

	register_console(&mtdoops_console);
	register_mtd_user(&mtdoops_notifier);
	return 0;
}

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

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


subsys_initcall(mtdoops_console_init);
module_exit(mtdoops_console_exit);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Richard Purdie <rpurdie@openedhand.com>");
MODULE_DESCRIPTION("MTD Oops/Panic console logger/driver");
Commit	Line	Data
4b23aff0 RP	1	/*
	2	* MTD Oops/Panic logger
	3	*
	4	* Copyright (C) 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/mtd/mtd.h>
	32
	33	#define OOPS_PAGE_SIZE 4096
	34
6ce0a856	35	struct mtdoops_context {
4b23aff0	36	int mtd_index;
6ce0a856 RP	37	struct work_struct work_erase;
6ce0a856 RP	38	struct work_struct work_write;
4b23aff0 RP	39	struct mtd_info *mtd;
	40	int oops_pages;
	41	int nextpage;
	42	int nextcount;
	43
	44	void *oops_buf;
	45	int ready;
	46	int writecount;
	47	} oops_cxt;
	48
	49	static void mtdoops_erase_callback(struct erase_info *done)
	50	{
	51	wait_queue_head_t wait_q = (wait_queue_head_t )done->priv;
	52	wake_up(wait_q);
	53	}
	54
	55	static int mtdoops_erase_block(struct mtd_info *mtd, int offset)
	56	{
	57	struct erase_info erase;
	58	DECLARE_WAITQUEUE(wait, current);
	59	wait_queue_head_t wait_q;
	60	int ret;
	61
	62	init_waitqueue_head(&wait_q);
	63	erase.mtd = mtd;
	64	erase.callback = mtdoops_erase_callback;
	65	erase.addr = offset;
	66	if (mtd->erasesize < OOPS_PAGE_SIZE)
	67	erase.len = OOPS_PAGE_SIZE;
	68	else
	69	erase.len = mtd->erasesize;
	70	erase.priv = (u_long)&wait_q;
	71
	72	set_current_state(TASK_INTERRUPTIBLE);
	73	add_wait_queue(&wait_q, &wait);
	74
	75	ret = mtd->erase(mtd, &erase);
	76	if (ret) {
	77	set_current_state(TASK_RUNNING);
	78	remove_wait_queue(&wait_q, &wait);
	79	printk (KERN_WARNING "mtdoops: erase of region [0x%x, 0x%x] "
	80	"on \"%s\" failed\n",
	81	erase.addr, erase.len, mtd->name);
	82	return ret;
	83	}
	84
	85	schedule(); /* Wait for erase to finish. */
	86	remove_wait_queue(&wait_q, &wait);
	87
	88	return 0;
	89	}
	90
6ce0a856	91	static void mtdoops_inc_counter(struct mtdoops_context *cxt)
4b23aff0 RP	92	{
	93	struct mtd_info *mtd = cxt->mtd;
	94	size_t retlen;
	95	u32 count;
	96	int ret;
	97
	98	cxt->nextpage++;
	99	if (cxt->nextpage > cxt->oops_pages)
	100	cxt->nextpage = 0;
	101	cxt->nextcount++;
	102	if (cxt->nextcount == 0xffffffff)
	103	cxt->nextcount = 0;
	104
	105	ret = mtd->read(mtd, cxt->nextpage * OOPS_PAGE_SIZE, 4,
	106	&retlen, (u_char *) &count);
2986bd2a	107	if ((retlen != 4) \|\| ((ret < 0) && (ret != -EUCLEAN))) {
68d09b1b	108	printk(KERN_ERR "mtdoops: Read failure at %d (%td of 4 read)"
4b23aff0 RP	109	", err %d.\n", cxt->nextpage * OOPS_PAGE_SIZE,
4b23aff0 RP	110	retlen, ret);
6ce0a856 RP	111	schedule_work(&cxt->work_erase);
6ce0a856 RP	112	return;
4b23aff0 RP	113	}
	114
	115	/* See if we need to erase the next block */
6ce0a856 RP	116	if (count != 0xffffffff) {
	117	schedule_work(&cxt->work_erase);
	118	return;
	119	}
4b23aff0 RP	120
	121	printk(KERN_DEBUG "mtdoops: Ready %d, %d (no erase)\n",
	122	cxt->nextpage, cxt->nextcount);
	123	cxt->ready = 1;
4b23aff0 RP	124	}
4b23aff0 RP	125
6ce0a856 RP	126	/* Scheduled work - when we can't proceed without erasing a block */
6ce0a856 RP	127	static void mtdoops_workfunc_erase(struct work_struct *work)
4b23aff0	128	{
6ce0a856 RP	129	struct mtdoops_context *cxt =
6ce0a856 RP	130	container_of(work, struct mtdoops_context, work_erase);
4b23aff0 RP	131	struct mtd_info *mtd = cxt->mtd;
	132	int i = 0, j, ret, mod;
	133
	134	/* We were unregistered */
	135	if (!mtd)
	136	return;
	137
	138	mod = (cxt->nextpage * OOPS_PAGE_SIZE) % mtd->erasesize;
	139	if (mod != 0) {
	140	cxt->nextpage = cxt->nextpage + ((mtd->erasesize - mod) / OOPS_PAGE_SIZE);
	141	if (cxt->nextpage > cxt->oops_pages)
	142	cxt->nextpage = 0;
	143	}
	144
2986bd2a RP	145	while (mtd->block_isbad) {
	146	ret = mtd->block_isbad(mtd, cxt->nextpage * OOPS_PAGE_SIZE);
	147	if (!ret)
	148	break;
	149	if (ret < 0) {
	150	printk(KERN_ERR "mtdoops: block_isbad failed, aborting.\n");
	151	return;
	152	}
4b23aff0 RP	153	badblock:
	154	printk(KERN_WARNING "mtdoops: Bad block at %08x\n",
	155	cxt->nextpage * OOPS_PAGE_SIZE);
	156	i++;
	157	cxt->nextpage = cxt->nextpage + (mtd->erasesize / OOPS_PAGE_SIZE);
	158	if (cxt->nextpage > cxt->oops_pages)
	159	cxt->nextpage = 0;
	160	if (i == (cxt->oops_pages / (mtd->erasesize / OOPS_PAGE_SIZE))) {
	161	printk(KERN_ERR "mtdoops: All blocks bad!\n");
	162	return;
	163	}
	164	}
	165
	166	for (j = 0, ret = -1; (j < 3) && (ret < 0); j++)
	167	ret = mtdoops_erase_block(mtd, cxt->nextpage * OOPS_PAGE_SIZE);
	168
2986bd2a RP	169	if (ret >= 0) {
	170	printk(KERN_DEBUG "mtdoops: Ready %d, %d \n", cxt->nextpage, cxt->nextcount);
	171	cxt->ready = 1;
	172	return;
4b23aff0 RP	173	}
4b23aff0 RP	174
2986bd2a RP	175	if (mtd->block_markbad && (ret == -EIO)) {
	176	ret = mtd->block_markbad(mtd, cxt->nextpage * OOPS_PAGE_SIZE);
	177	if (ret < 0) {
	178	printk(KERN_ERR "mtdoops: block_markbad failed, aborting.\n");
	179	return;
	180	}
	181	}
	182	goto badblock;
4b23aff0 RP	183	}
4b23aff0 RP	184
6ce0a856	185	static void mtdoops_workfunc_write(struct work_struct *work)
4b23aff0 RP	186	{
4b23aff0 RP	187	struct mtdoops_context *cxt =
6ce0a856 RP	188	container_of(work, struct mtdoops_context, work_write);
	189	struct mtd_info *mtd = cxt->mtd;
	190	size_t retlen;
	191	int ret;
4b23aff0	192
6ce0a856 RP	193	if (cxt->writecount < OOPS_PAGE_SIZE)
	194	memset(cxt->oops_buf + cxt->writecount, 0xff,
	195	OOPS_PAGE_SIZE - cxt->writecount);
	196
	197	ret = mtd->write(mtd, cxt->nextpage * OOPS_PAGE_SIZE,
	198	OOPS_PAGE_SIZE, &retlen, cxt->oops_buf);
	199
	200	cxt->writecount = 0;
	201
	202	if ((retlen != OOPS_PAGE_SIZE) \|\| (ret < 0))
	203	printk(KERN_ERR "mtdoops: Write failure at %d (%td of %d written), err %d.\n",
	204	cxt->nextpage * OOPS_PAGE_SIZE, retlen, OOPS_PAGE_SIZE, ret);
	205
	206	mtdoops_inc_counter(cxt);
	207	}
4b23aff0	208
6ce0a856	209	static void find_next_position(struct mtdoops_context *cxt)
4b23aff0 RP	210	{
4b23aff0 RP	211	struct mtd_info *mtd = cxt->mtd;
2986bd2a	212	int ret, page, maxpos = 0;
4b23aff0 RP	213	u32 count, maxcount = 0xffffffff;
	214	size_t retlen;
	215
	216	for (page = 0; page < cxt->oops_pages; page++) {
2986bd2a RP	217	ret = mtd->read(mtd, page * OOPS_PAGE_SIZE, 4, &retlen, (u_char *) &count);
	218	if ((retlen != 4) \|\| ((ret < 0) && (ret != -EUCLEAN))) {
	219	printk(KERN_ERR "mtdoops: Read failure at %d (%td of 4 read)"
	220	", err %d.\n", page * OOPS_PAGE_SIZE, retlen, ret);
	221	continue;
	222	}
	223
4b23aff0 RP	224	if (count == 0xffffffff)
	225	continue;
	226	if (maxcount == 0xffffffff) {
	227	maxcount = count;
	228	maxpos = page;
	229	} else if ((count < 0x40000000) && (maxcount > 0xc0000000)) {
	230	maxcount = count;
	231	maxpos = page;
	232	} else if ((count > maxcount) && (count < 0xc0000000)) {
	233	maxcount = count;
	234	maxpos = page;
	235	} else if ((count > maxcount) && (count > 0xc0000000)
	236	&& (maxcount > 0x80000000)) {
	237	maxcount = count;
	238	maxpos = page;
	239	}
	240	}
	241	if (maxcount == 0xffffffff) {
	242	cxt->nextpage = 0;
	243	cxt->nextcount = 1;
	244	cxt->ready = 1;
	245	printk(KERN_DEBUG "mtdoops: Ready %d, %d (first init)\n",
	246	cxt->nextpage, cxt->nextcount);
6ce0a856	247	return;
4b23aff0 RP	248	}
	249
	250	cxt->nextpage = maxpos;
	251	cxt->nextcount = maxcount;
	252
6ce0a856	253	mtdoops_inc_counter(cxt);
4b23aff0 RP	254	}
	255
	256
	257	static void mtdoops_notify_add(struct mtd_info *mtd)
	258	{
	259	struct mtdoops_context *cxt = &oops_cxt;
4b23aff0 RP	260
	261	if ((mtd->index != cxt->mtd_index) \|\| cxt->mtd_index < 0)
	262	return;
	263
	264	if (mtd->size < (mtd->erasesize * 2)) {
	265	printk(KERN_ERR "MTD partition %d not big enough for mtdoops\n",
	266	mtd->index);
	267	return;
	268	}
	269
	270	cxt->mtd = mtd;
	271	cxt->oops_pages = mtd->size / OOPS_PAGE_SIZE;
	272
6ce0a856	273	find_next_position(cxt);
4b23aff0 RP	274
	275	printk(KERN_DEBUG "mtdoops: Attached to MTD device %d\n", mtd->index);
	276	}
	277
	278	static void mtdoops_notify_remove(struct mtd_info *mtd)
	279	{
	280	struct mtdoops_context *cxt = &oops_cxt;
	281
	282	if ((mtd->index != cxt->mtd_index) \|\| cxt->mtd_index < 0)
	283	return;
	284
	285	cxt->mtd = NULL;
	286	flush_scheduled_work();
	287	}
	288
8691a729	289	static void mtdoops_console_sync(void)
4b23aff0	290	{
8691a729	291	struct mtdoops_context *cxt = &oops_cxt;
4b23aff0	292	struct mtd_info *mtd = cxt->mtd;
4b23aff0	293
6ce0a856	294	if (!cxt->ready \|\| !mtd \|\| cxt->writecount == 0)
4b23aff0 RP	295	return;
4b23aff0 RP	296
8691a729	297	cxt->ready = 0;
8691a729	298
6ce0a856	299	schedule_work(&cxt->work_write);
8691a729 RP	300	}
	301
	302	static void
	303	mtdoops_console_write(struct console co, const char s, unsigned int count)
	304	{
	305	struct mtdoops_context *cxt = co->data;
	306	struct mtd_info *mtd = cxt->mtd;
8691a729 RP	307
	308	if (!oops_in_progress) {
	309	mtdoops_console_sync();
	310	return;
4b23aff0 RP	311	}
4b23aff0 RP	312
8691a729	313	if (!cxt->ready \|\| !mtd)
4b23aff0 RP	314	return;
	315
	316	if (cxt->writecount == 0) {
	317	u32 *stamp = cxt->oops_buf;
	318	*stamp = cxt->nextcount;
	319	cxt->writecount = 4;
	320	}
	321
	322	if ((count + cxt->writecount) > OOPS_PAGE_SIZE)
	323	count = OOPS_PAGE_SIZE - cxt->writecount;
	324
235d6200 PK	325	memcpy(cxt->oops_buf + cxt->writecount, s, count);
235d6200 PK	326	cxt->writecount += count;
4b23aff0 RP	327	}
	328
	329	static int __init mtdoops_console_setup(struct console co, char options)
	330	{
	331	struct mtdoops_context *cxt = co->data;
	332
	333	if (cxt->mtd_index != -1)
	334	return -EBUSY;
	335	if (co->index == -1)
	336	return -EINVAL;
	337
	338	cxt->mtd_index = co->index;
	339	return 0;
	340	}
	341
	342	static struct mtd_notifier mtdoops_notifier = {
	343	.add = mtdoops_notify_add,
	344	.remove = mtdoops_notify_remove,
	345	};
	346
	347	static struct console mtdoops_console = {
	348	.name = "ttyMTD",
	349	.write = mtdoops_console_write,
	350	.setup = mtdoops_console_setup,
8691a729	351	.unblank = mtdoops_console_sync,
4b23aff0 RP	352	.flags = CON_PRINTBUFFER,
	353	.index = -1,
	354	.data = &oops_cxt,
	355	};
	356
	357	static int __init mtdoops_console_init(void)
	358	{
	359	struct mtdoops_context *cxt = &oops_cxt;
	360
	361	cxt->mtd_index = -1;
	362	cxt->oops_buf = vmalloc(OOPS_PAGE_SIZE);
	363
	364	if (!cxt->oops_buf) {
	365	printk(KERN_ERR "Failed to allocate oops buffer workspace\n");
	366	return -ENOMEM;
	367	}
	368
6ce0a856 RP	369	INIT_WORK(&cxt->work_erase, mtdoops_workfunc_erase);
6ce0a856 RP	370	INIT_WORK(&cxt->work_write, mtdoops_workfunc_write);
4b23aff0 RP	371
	372	register_console(&mtdoops_console);
	373	register_mtd_user(&mtdoops_notifier);
	374	return 0;
	375	}
	376
	377	static void __exit mtdoops_console_exit(void)
	378	{
	379	struct mtdoops_context *cxt = &oops_cxt;
	380
	381	unregister_mtd_user(&mtdoops_notifier);
	382	unregister_console(&mtdoops_console);
	383	vfree(cxt->oops_buf);
	384	}
	385
	386
	387	subsys_initcall(mtdoops_console_init);
	388	module_exit(mtdoops_console_exit);
	389
	390	MODULE_LICENSE("GPL");
	391	MODULE_AUTHOR("Richard Purdie <rpurdie@openedhand.com>");
	392	MODULE_DESCRIPTION("MTD Oops/Panic console logger/driver");