[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/delay.h>
#include <linux/spinlock.h>
#include <linux/interrupt.h>
#include <linux/mtd/mtd.h>

#define MTDOOPS_KERNMSG_MAGIC 0x5d005d00
#define OOPS_PAGE_SIZE 4096

static 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;
	char *name;

	void *oops_buf;

	/* writecount and disabling ready are spin lock protected */
	spinlock_t writecount_lock;
	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;
	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%llx, 0x%llx] "
				     "on \"%s\" failed\n",
			(unsigned long long)erase.addr, (unsigned long long)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_write(struct mtdoops_context *cxt, int panic)
{
	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);

	if (panic)
		ret = mtd->panic_write(mtd, cxt->nextpage * OOPS_PAGE_SIZE,
					OOPS_PAGE_SIZE, &retlen, cxt->oops_buf);
	else
		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 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++) {
		ret = mtd->read(mtd, page * OOPS_PAGE_SIZE, 8, &retlen, (u_char *) &count[0]);
		if ((retlen != 8) || ((ret < 0) && (ret != -EUCLEAN))) {
			printk(KERN_ERR "mtdoops: Read failure at %d (%td of 8 read)"
				", err %d.\n", page * OOPS_PAGE_SIZE, retlen, ret);
			continue;
		}

		if (count[1] != MTDOOPS_KERNMSG_MAGIC)
			continue;
		if (count[0] == 0xffffffff)
			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 = 0;
		cxt->nextcount = 1;
		schedule_work(&cxt->work_erase);
		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 (cxt->name && !strcmp(mtd->name, cxt->name))
		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 "MTD partition %d not big enough for mtdoops\n",
				mtd->index);
		return;
	}

	if (mtd->erasesize < OOPS_PAGE_SIZE) {
		printk(KERN_ERR "Eraseblock size of MTD partition %d too small\n",
				mtd->index);
		return;
	}

	cxt->mtd = mtd;
	if (mtd->size > INT_MAX)
		cxt->oops_pages = INT_MAX / OOPS_PAGE_SIZE;
	else
		cxt->oops_pages = (int)mtd->size / OOPS_PAGE_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;

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

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

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

	/* 
	 *  Once ready is 0 and we've held the lock no further writes to the 
	 *  buffer will happen
	 */
	spin_lock_irqsave(&cxt->writecount_lock, flags);
	if (!cxt->ready) {
		spin_unlock_irqrestore(&cxt->writecount_lock, flags);
		return;
	}
	cxt->ready = 0;
	spin_unlock_irqrestore(&cxt->writecount_lock, flags);

	if (mtd->panic_write && in_interrupt())
		/* Interrupt context, we're going to panic so try and log */
		mtdoops_write(cxt, 1);
	else
		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;
	unsigned long flags;

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

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

	/* Locking on writecount ensures sequential writes to the buffer */
	spin_lock_irqsave(&cxt->writecount_lock, flags);

	/* Check ready status didn't change whilst waiting for the lock */
	if (!cxt->ready) {
		spin_unlock_irqrestore(&cxt->writecount_lock, flags);
		return;
	}

	if (cxt->writecount == 0) {
		u32 *stamp = cxt->oops_buf;
		*stamp++ = cxt->nextcount;
		*stamp = MTDOOPS_KERNMSG_MAGIC;
		cxt->writecount = 8;
	}

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

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

	spin_unlock_irqrestore(&cxt->writecount_lock, flags);

	if (cxt->writecount == OOPS_PAGE_SIZE)
		mtdoops_console_sync();
}

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

	if (cxt->mtd_index != -1 || cxt->name)
		return -EBUSY;
	if (options) {
		cxt->name = kstrdup(options, GFP_KERNEL);
		return 0;
	}
	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,
	.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);
	spin_lock_init(&cxt->writecount_lock);

	if (!cxt->oops_buf) {
		printk(KERN_ERR "Failed to allocate mtdoops 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);
	kfree(cxt->name);
	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>
621e4f8e	31	#include <linux/delay.h>
47c152b8	32	#include <linux/spinlock.h>
f9f7dd22	33	#include <linux/interrupt.h>
4b23aff0 RP	34	#include <linux/mtd/mtd.h>
4b23aff0 RP	35
f0482ee3	36	#define MTDOOPS_KERNMSG_MAGIC 0x5d005d00
4b23aff0 RP	37	#define OOPS_PAGE_SIZE 4096
4b23aff0 RP	38
7903cbab	39	static struct mtdoops_context {
4b23aff0	40	int mtd_index;
6ce0a856 RP	41	struct work_struct work_erase;
6ce0a856 RP	42	struct work_struct work_write;
4b23aff0 RP	43	struct mtd_info *mtd;
	44	int oops_pages;
	45	int nextpage;
	46	int nextcount;
e2a0f25b	47	char *name;
4b23aff0 RP	48
4b23aff0 RP	49	void *oops_buf;
47c152b8 RP	50
	51	/* writecount and disabling ready are spin lock protected */
	52	spinlock_t writecount_lock;
4b23aff0 RP	53	int ready;
	54	int writecount;
	55	} oops_cxt;
	56
	57	static void mtdoops_erase_callback(struct erase_info *done)
	58	{
	59	wait_queue_head_t wait_q = (wait_queue_head_t )done->priv;
	60	wake_up(wait_q);
	61	}
	62
	63	static int mtdoops_erase_block(struct mtd_info *mtd, int offset)
	64	{
	65	struct erase_info erase;
	66	DECLARE_WAITQUEUE(wait, current);
	67	wait_queue_head_t wait_q;
	68	int ret;
	69
	70	init_waitqueue_head(&wait_q);
	71	erase.mtd = mtd;
	72	erase.callback = mtdoops_erase_callback;
	73	erase.addr = offset;
79dcd8e9	74	erase.len = mtd->erasesize;
4b23aff0 RP	75	erase.priv = (u_long)&wait_q;
	76
	77	set_current_state(TASK_INTERRUPTIBLE);
	78	add_wait_queue(&wait_q, &wait);
	79
	80	ret = mtd->erase(mtd, &erase);
	81	if (ret) {
	82	set_current_state(TASK_RUNNING);
	83	remove_wait_queue(&wait_q, &wait);
69423d99	84	printk (KERN_WARNING "mtdoops: erase of region [0x%llx, 0x%llx] "
4b23aff0	85	"on \"%s\" failed\n",
69423d99	86	(unsigned long long)erase.addr, (unsigned long long)erase.len, mtd->name);
4b23aff0 RP	87	return ret;
	88	}
	89
	90	schedule(); /* Wait for erase to finish. */
	91	remove_wait_queue(&wait_q, &wait);
	92
	93	return 0;
	94	}
	95
6ce0a856	96	static void mtdoops_inc_counter(struct mtdoops_context *cxt)
4b23aff0 RP	97	{
	98	struct mtd_info *mtd = cxt->mtd;
	99	size_t retlen;
	100	u32 count;
	101	int ret;
	102
	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
	110	ret = mtd->read(mtd, cxt->nextpage * OOPS_PAGE_SIZE, 4,
	111	&retlen, (u_char *) &count);
2986bd2a	112	if ((retlen != 4) \|\| ((ret < 0) && (ret != -EUCLEAN))) {
68d09b1b	113	printk(KERN_ERR "mtdoops: Read failure at %d (%td of 4 read)"
4b23aff0 RP	114	", err %d.\n", cxt->nextpage * OOPS_PAGE_SIZE,
4b23aff0 RP	115	retlen, ret);
6ce0a856 RP	116	schedule_work(&cxt->work_erase);
6ce0a856 RP	117	return;
4b23aff0 RP	118	}
	119
	120	/* See if we need to erase the next block */
6ce0a856 RP	121	if (count != 0xffffffff) {
	122	schedule_work(&cxt->work_erase);
	123	return;
	124	}
4b23aff0 RP	125
	126	printk(KERN_DEBUG "mtdoops: Ready %d, %d (no erase)\n",
	127	cxt->nextpage, cxt->nextcount);
	128	cxt->ready = 1;
4b23aff0 RP	129	}
4b23aff0 RP	130
6ce0a856 RP	131	/* Scheduled work - when we can't proceed without erasing a block */
6ce0a856 RP	132	static void mtdoops_workfunc_erase(struct work_struct *work)
4b23aff0	133	{
6ce0a856 RP	134	struct mtdoops_context *cxt =
6ce0a856 RP	135	container_of(work, struct mtdoops_context, work_erase);
4b23aff0 RP	136	struct mtd_info *mtd = cxt->mtd;
	137	int i = 0, j, ret, mod;
	138
	139	/* We were unregistered */
	140	if (!mtd)
	141	return;
	142
	143	mod = (cxt->nextpage * OOPS_PAGE_SIZE) % mtd->erasesize;
	144	if (mod != 0) {
	145	cxt->nextpage = cxt->nextpage + ((mtd->erasesize - mod) / OOPS_PAGE_SIZE);
ecd5b310	146	if (cxt->nextpage >= cxt->oops_pages)
4b23aff0 RP	147	cxt->nextpage = 0;
	148	}
	149
2986bd2a RP	150	while (mtd->block_isbad) {
	151	ret = mtd->block_isbad(mtd, cxt->nextpage * OOPS_PAGE_SIZE);
	152	if (!ret)
	153	break;
	154	if (ret < 0) {
	155	printk(KERN_ERR "mtdoops: block_isbad failed, aborting.\n");
	156	return;
	157	}
4b23aff0 RP	158	badblock:
	159	printk(KERN_WARNING "mtdoops: Bad block at %08x\n",
	160	cxt->nextpage * OOPS_PAGE_SIZE);
	161	i++;
	162	cxt->nextpage = cxt->nextpage + (mtd->erasesize / OOPS_PAGE_SIZE);
ecd5b310	163	if (cxt->nextpage >= cxt->oops_pages)
4b23aff0 RP	164	cxt->nextpage = 0;
	165	if (i == (cxt->oops_pages / (mtd->erasesize / OOPS_PAGE_SIZE))) {
	166	printk(KERN_ERR "mtdoops: All blocks bad!\n");
	167	return;
	168	}
	169	}
	170
	171	for (j = 0, ret = -1; (j < 3) && (ret < 0); j++)
	172	ret = mtdoops_erase_block(mtd, cxt->nextpage * OOPS_PAGE_SIZE);
	173
2986bd2a RP	174	if (ret >= 0) {
	175	printk(KERN_DEBUG "mtdoops: Ready %d, %d \n", cxt->nextpage, cxt->nextcount);
	176	cxt->ready = 1;
	177	return;
4b23aff0 RP	178	}
4b23aff0 RP	179
2986bd2a RP	180	if (mtd->block_markbad && (ret == -EIO)) {
	181	ret = mtd->block_markbad(mtd, cxt->nextpage * OOPS_PAGE_SIZE);
	182	if (ret < 0) {
	183	printk(KERN_ERR "mtdoops: block_markbad failed, aborting.\n");
	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;
	193	size_t retlen;
	194	int ret;
4b23aff0	195
6ce0a856 RP	196	if (cxt->writecount < OOPS_PAGE_SIZE)
	197	memset(cxt->oops_buf + cxt->writecount, 0xff,
	198	OOPS_PAGE_SIZE - cxt->writecount);
	199
621e4f8e RP	200	if (panic)
	201	ret = mtd->panic_write(mtd, cxt->nextpage * OOPS_PAGE_SIZE,
	202	OOPS_PAGE_SIZE, &retlen, cxt->oops_buf);
	203	else
	204	ret = mtd->write(mtd, cxt->nextpage * OOPS_PAGE_SIZE,
6ce0a856 RP	205	OOPS_PAGE_SIZE, &retlen, cxt->oops_buf);
	206
	207	cxt->writecount = 0;
	208
	209	if ((retlen != OOPS_PAGE_SIZE) \|\| (ret < 0))
	210	printk(KERN_ERR "mtdoops: Write failure at %d (%td of %d written), err %d.\n",
	211	cxt->nextpage * OOPS_PAGE_SIZE, retlen, OOPS_PAGE_SIZE, ret);
	212
	213	mtdoops_inc_counter(cxt);
621e4f8e RP	214	}
	215
	216
	217	static void mtdoops_workfunc_write(struct work_struct *work)
	218	{
	219	struct mtdoops_context *cxt =
	220	container_of(work, struct mtdoops_context, work_write);
	221
	222	mtdoops_write(cxt, 0);
6ce0a856	223	}
4b23aff0	224
6ce0a856	225	static void find_next_position(struct mtdoops_context *cxt)
4b23aff0 RP	226	{
4b23aff0 RP	227	struct mtd_info *mtd = cxt->mtd;
2986bd2a	228	int ret, page, maxpos = 0;
f0482ee3	229	u32 count[2], maxcount = 0xffffffff;
4b23aff0 RP	230	size_t retlen;
	231
	232	for (page = 0; page < cxt->oops_pages; page++) {
f0482ee3 RP	233	ret = mtd->read(mtd, page * OOPS_PAGE_SIZE, 8, &retlen, (u_char *) &count[0]);
	234	if ((retlen != 8) \|\| ((ret < 0) && (ret != -EUCLEAN))) {
	235	printk(KERN_ERR "mtdoops: Read failure at %d (%td of 8 read)"
2986bd2a RP	236	", err %d.\n", page * OOPS_PAGE_SIZE, retlen, ret);
	237	continue;
	238	}
	239
f0482ee3 RP	240	if (count[1] != MTDOOPS_KERNMSG_MAGIC)
	241	continue;
	242	if (count[0] == 0xffffffff)
4b23aff0 RP	243	continue;
4b23aff0 RP	244	if (maxcount == 0xffffffff) {
f0482ee3	245	maxcount = count[0];
4b23aff0	246	maxpos = page;
f0482ee3 RP	247	} else if ((count[0] < 0x40000000) && (maxcount > 0xc0000000)) {
f0482ee3 RP	248	maxcount = count[0];
4b23aff0	249	maxpos = page;
f0482ee3 RP	250	} else if ((count[0] > maxcount) && (count[0] < 0xc0000000)) {
f0482ee3 RP	251	maxcount = count[0];
4b23aff0	252	maxpos = page;
f0482ee3	253	} else if ((count[0] > maxcount) && (count[0] > 0xc0000000)
4b23aff0	254	&& (maxcount > 0x80000000)) {
f0482ee3	255	maxcount = count[0];
4b23aff0 RP	256	maxpos = page;
	257	}
	258	}
	259	if (maxcount == 0xffffffff) {
	260	cxt->nextpage = 0;
	261	cxt->nextcount = 1;
43b5693d	262	schedule_work(&cxt->work_erase);
6ce0a856	263	return;
4b23aff0 RP	264	}
	265
	266	cxt->nextpage = maxpos;
	267	cxt->nextcount = maxcount;
	268
6ce0a856	269	mtdoops_inc_counter(cxt);
4b23aff0 RP	270	}
	271
	272
	273	static void mtdoops_notify_add(struct mtd_info *mtd)
	274	{
	275	struct mtdoops_context *cxt = &oops_cxt;
4b23aff0	276
e2a0f25b AH	277	if (cxt->name && !strcmp(mtd->name, cxt->name))
	278	cxt->mtd_index = mtd->index;
	279
4b23aff0 RP	280	if ((mtd->index != cxt->mtd_index) \|\| cxt->mtd_index < 0)
	281	return;
	282
	283	if (mtd->size < (mtd->erasesize * 2)) {
	284	printk(KERN_ERR "MTD partition %d not big enough for mtdoops\n",
	285	mtd->index);
	286	return;
	287	}
	288
79dcd8e9 RP	289	if (mtd->erasesize < OOPS_PAGE_SIZE) {
	290	printk(KERN_ERR "Eraseblock size of MTD partition %d too small\n",
	291	mtd->index);
	292	return;
	293	}
	294
4b23aff0	295	cxt->mtd = mtd;
69423d99 AH	296	if (mtd->size > INT_MAX)
	297	cxt->oops_pages = INT_MAX / OOPS_PAGE_SIZE;
	298	else
	299	cxt->oops_pages = (int)mtd->size / OOPS_PAGE_SIZE;
4b23aff0	300
6ce0a856	301	find_next_position(cxt);
4b23aff0	302
79dcd8e9	303	printk(KERN_INFO "mtdoops: Attached to MTD device %d\n", mtd->index);
4b23aff0 RP	304	}
	305
	306	static void mtdoops_notify_remove(struct mtd_info *mtd)
	307	{
	308	struct mtdoops_context *cxt = &oops_cxt;
	309
	310	if ((mtd->index != cxt->mtd_index) \|\| cxt->mtd_index < 0)
	311	return;
	312
	313	cxt->mtd = NULL;
	314	flush_scheduled_work();
	315	}
	316
8691a729	317	static void mtdoops_console_sync(void)
4b23aff0	318	{
8691a729	319	struct mtdoops_context *cxt = &oops_cxt;
4b23aff0	320	struct mtd_info *mtd = cxt->mtd;
47c152b8	321	unsigned long flags;
4b23aff0	322
6ce0a856	323	if (!cxt->ready \|\| !mtd \|\| cxt->writecount == 0)
4b23aff0 RP	324	return;
4b23aff0 RP	325
47c152b8 RP	326	/*
	327	* Once ready is 0 and we've held the lock no further writes to the
	328	* buffer will happen
	329	*/
	330	spin_lock_irqsave(&cxt->writecount_lock, flags);
	331	if (!cxt->ready) {
	332	spin_unlock_irqrestore(&cxt->writecount_lock, flags);
	333	return;
	334	}
8691a729	335	cxt->ready = 0;
47c152b8	336	spin_unlock_irqrestore(&cxt->writecount_lock, flags);
8691a729	337
621e4f8e RP	338	if (mtd->panic_write && in_interrupt())
	339	/* Interrupt context, we're going to panic so try and log */
	340	mtdoops_write(cxt, 1);
	341	else
	342	schedule_work(&cxt->work_write);
8691a729 RP	343	}
	344
	345	static void
	346	mtdoops_console_write(struct console co, const char s, unsigned int count)
	347	{
	348	struct mtdoops_context *cxt = co->data;
	349	struct mtd_info *mtd = cxt->mtd;
47c152b8	350	unsigned long flags;
8691a729 RP	351
	352	if (!oops_in_progress) {
	353	mtdoops_console_sync();
	354	return;
4b23aff0 RP	355	}
4b23aff0 RP	356
8691a729	357	if (!cxt->ready \|\| !mtd)
4b23aff0 RP	358	return;
4b23aff0 RP	359
47c152b8 RP	360	/* Locking on writecount ensures sequential writes to the buffer */
	361	spin_lock_irqsave(&cxt->writecount_lock, flags);
	362
	363	/* Check ready status didn't change whilst waiting for the lock */
48ec00ac AH	364	if (!cxt->ready) {
48ec00ac AH	365	spin_unlock_irqrestore(&cxt->writecount_lock, flags);
47c152b8	366	return;
48ec00ac	367	}
47c152b8	368
4b23aff0 RP	369	if (cxt->writecount == 0) {
4b23aff0 RP	370	u32 *stamp = cxt->oops_buf;
f0482ee3 RP	371	*stamp++ = cxt->nextcount;
	372	*stamp = MTDOOPS_KERNMSG_MAGIC;
	373	cxt->writecount = 8;
4b23aff0 RP	374	}
	375
	376	if ((count + cxt->writecount) > OOPS_PAGE_SIZE)
	377	count = OOPS_PAGE_SIZE - cxt->writecount;
	378
235d6200 PK	379	memcpy(cxt->oops_buf + cxt->writecount, s, count);
235d6200 PK	380	cxt->writecount += count;
47c152b8 RP	381
	382	spin_unlock_irqrestore(&cxt->writecount_lock, flags);
	383
	384	if (cxt->writecount == OOPS_PAGE_SIZE)
	385	mtdoops_console_sync();
4b23aff0 RP	386	}
	387
	388	static int __init mtdoops_console_setup(struct console co, char options)
	389	{
	390	struct mtdoops_context *cxt = co->data;
	391
e2a0f25b	392	if (cxt->mtd_index != -1 \|\| cxt->name)
4b23aff0	393	return -EBUSY;
e2a0f25b AH	394	if (options) {
	395	cxt->name = kstrdup(options, GFP_KERNEL);
	396	return 0;
	397	}
4b23aff0 RP	398	if (co->index == -1)
	399	return -EINVAL;
	400
	401	cxt->mtd_index = co->index;
	402	return 0;
	403	}
	404
	405	static struct mtd_notifier mtdoops_notifier = {
	406	.add = mtdoops_notify_add,
	407	.remove = mtdoops_notify_remove,
	408	};
	409
	410	static struct console mtdoops_console = {
	411	.name = "ttyMTD",
	412	.write = mtdoops_console_write,
	413	.setup = mtdoops_console_setup,
8691a729	414	.unblank = mtdoops_console_sync,
4b23aff0 RP	415	.index = -1,
	416	.data = &oops_cxt,
	417	};
	418
	419	static int __init mtdoops_console_init(void)
	420	{
	421	struct mtdoops_context *cxt = &oops_cxt;
	422
	423	cxt->mtd_index = -1;
	424	cxt->oops_buf = vmalloc(OOPS_PAGE_SIZE);
48ec00ac	425	spin_lock_init(&cxt->writecount_lock);
4b23aff0 RP	426
4b23aff0 RP	427	if (!cxt->oops_buf) {
79dcd8e9	428	printk(KERN_ERR "Failed to allocate mtdoops buffer workspace\n");
4b23aff0 RP	429	return -ENOMEM;
	430	}
	431
6ce0a856 RP	432	INIT_WORK(&cxt->work_erase, mtdoops_workfunc_erase);
6ce0a856 RP	433	INIT_WORK(&cxt->work_write, mtdoops_workfunc_write);
4b23aff0 RP	434
	435	register_console(&mtdoops_console);
	436	register_mtd_user(&mtdoops_notifier);
	437	return 0;
	438	}
	439
	440	static void __exit mtdoops_console_exit(void)
	441	{
	442	struct mtdoops_context *cxt = &oops_cxt;
	443
	444	unregister_mtd_user(&mtdoops_notifier);
	445	unregister_console(&mtdoops_console);
e2a0f25b	446	kfree(cxt->name);
4b23aff0 RP	447	vfree(cxt->oops_buf);
	448	}
	449
	450
	451	subsys_initcall(mtdoops_console_init);
	452	module_exit(mtdoops_console_exit);
	453
	454	MODULE_LICENSE("GPL");
	455	MODULE_AUTHOR("Richard Purdie <rpurdie@openedhand.com>");
	456	MODULE_DESCRIPTION("MTD Oops/Panic console logger/driver");