[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;

	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 ((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)
		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)
		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,
	.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 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);
	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;
	47
	48	void *oops_buf;
47c152b8 RP	49
	50	/* writecount and disabling ready are spin lock protected */
	51	spinlock_t writecount_lock;
4b23aff0 RP	52	int ready;
	53	int writecount;
	54	} oops_cxt;
	55
	56	static void mtdoops_erase_callback(struct erase_info *done)
	57	{
	58	wait_queue_head_t wait_q = (wait_queue_head_t )done->priv;
	59	wake_up(wait_q);
	60	}
	61
	62	static int mtdoops_erase_block(struct mtd_info *mtd, int offset)
	63	{
	64	struct erase_info erase;
	65	DECLARE_WAITQUEUE(wait, current);
	66	wait_queue_head_t wait_q;
	67	int ret;
	68
	69	init_waitqueue_head(&wait_q);
	70	erase.mtd = mtd;
	71	erase.callback = mtdoops_erase_callback;
	72	erase.addr = offset;
79dcd8e9	73	erase.len = mtd->erasesize;
4b23aff0 RP	74	erase.priv = (u_long)&wait_q;
	75
	76	set_current_state(TASK_INTERRUPTIBLE);
	77	add_wait_queue(&wait_q, &wait);
	78
	79	ret = mtd->erase(mtd, &erase);
	80	if (ret) {
	81	set_current_state(TASK_RUNNING);
	82	remove_wait_queue(&wait_q, &wait);
69423d99	83	printk (KERN_WARNING "mtdoops: erase of region [0x%llx, 0x%llx] "
4b23aff0	84	"on \"%s\" failed\n",
69423d99	85	(unsigned long long)erase.addr, (unsigned long long)erase.len, mtd->name);
4b23aff0 RP	86	return ret;
	87	}
	88
	89	schedule(); /* Wait for erase to finish. */
	90	remove_wait_queue(&wait_q, &wait);
	91
	92	return 0;
	93	}
	94
6ce0a856	95	static void mtdoops_inc_counter(struct mtdoops_context *cxt)
4b23aff0 RP	96	{
	97	struct mtd_info *mtd = cxt->mtd;
	98	size_t retlen;
	99	u32 count;
	100	int ret;
	101
	102	cxt->nextpage++;
ecd5b310	103	if (cxt->nextpage >= cxt->oops_pages)
4b23aff0 RP	104	cxt->nextpage = 0;
	105	cxt->nextcount++;
	106	if (cxt->nextcount == 0xffffffff)
	107	cxt->nextcount = 0;
	108
	109	ret = mtd->read(mtd, cxt->nextpage * OOPS_PAGE_SIZE, 4,
	110	&retlen, (u_char *) &count);
2986bd2a	111	if ((retlen != 4) \|\| ((ret < 0) && (ret != -EUCLEAN))) {
68d09b1b	112	printk(KERN_ERR "mtdoops: Read failure at %d (%td of 4 read)"
4b23aff0 RP	113	", err %d.\n", cxt->nextpage * OOPS_PAGE_SIZE,
4b23aff0 RP	114	retlen, ret);
6ce0a856 RP	115	schedule_work(&cxt->work_erase);
6ce0a856 RP	116	return;
4b23aff0 RP	117	}
	118
	119	/* See if we need to erase the next block */
6ce0a856 RP	120	if (count != 0xffffffff) {
	121	schedule_work(&cxt->work_erase);
	122	return;
	123	}
4b23aff0 RP	124
	125	printk(KERN_DEBUG "mtdoops: Ready %d, %d (no erase)\n",
	126	cxt->nextpage, cxt->nextcount);
	127	cxt->ready = 1;
4b23aff0 RP	128	}
4b23aff0 RP	129
6ce0a856 RP	130	/* Scheduled work - when we can't proceed without erasing a block */
6ce0a856 RP	131	static void mtdoops_workfunc_erase(struct work_struct *work)
4b23aff0	132	{
6ce0a856 RP	133	struct mtdoops_context *cxt =
6ce0a856 RP	134	container_of(work, struct mtdoops_context, work_erase);
4b23aff0 RP	135	struct mtd_info *mtd = cxt->mtd;
	136	int i = 0, j, ret, mod;
	137
	138	/* We were unregistered */
	139	if (!mtd)
	140	return;
	141
	142	mod = (cxt->nextpage * OOPS_PAGE_SIZE) % mtd->erasesize;
	143	if (mod != 0) {
	144	cxt->nextpage = cxt->nextpage + ((mtd->erasesize - mod) / OOPS_PAGE_SIZE);
ecd5b310	145	if (cxt->nextpage >= cxt->oops_pages)
4b23aff0 RP	146	cxt->nextpage = 0;
	147	}
	148
2986bd2a RP	149	while (mtd->block_isbad) {
	150	ret = mtd->block_isbad(mtd, cxt->nextpage * OOPS_PAGE_SIZE);
	151	if (!ret)
	152	break;
	153	if (ret < 0) {
	154	printk(KERN_ERR "mtdoops: block_isbad failed, aborting.\n");
	155	return;
	156	}
4b23aff0 RP	157	badblock:
	158	printk(KERN_WARNING "mtdoops: Bad block at %08x\n",
	159	cxt->nextpage * OOPS_PAGE_SIZE);
	160	i++;
	161	cxt->nextpage = cxt->nextpage + (mtd->erasesize / OOPS_PAGE_SIZE);
ecd5b310	162	if (cxt->nextpage >= cxt->oops_pages)
4b23aff0 RP	163	cxt->nextpage = 0;
	164	if (i == (cxt->oops_pages / (mtd->erasesize / OOPS_PAGE_SIZE))) {
	165	printk(KERN_ERR "mtdoops: All blocks bad!\n");
	166	return;
	167	}
	168	}
	169
	170	for (j = 0, ret = -1; (j < 3) && (ret < 0); j++)
	171	ret = mtdoops_erase_block(mtd, cxt->nextpage * OOPS_PAGE_SIZE);
	172
2986bd2a RP	173	if (ret >= 0) {
	174	printk(KERN_DEBUG "mtdoops: Ready %d, %d \n", cxt->nextpage, cxt->nextcount);
	175	cxt->ready = 1;
	176	return;
4b23aff0 RP	177	}
4b23aff0 RP	178
2986bd2a RP	179	if (mtd->block_markbad && (ret == -EIO)) {
	180	ret = mtd->block_markbad(mtd, cxt->nextpage * OOPS_PAGE_SIZE);
	181	if (ret < 0) {
	182	printk(KERN_ERR "mtdoops: block_markbad failed, aborting.\n");
	183	return;
	184	}
	185	}
	186	goto badblock;
4b23aff0 RP	187	}
4b23aff0 RP	188
621e4f8e	189	static void mtdoops_write(struct mtdoops_context *cxt, int panic)
4b23aff0	190	{
6ce0a856 RP	191	struct mtd_info *mtd = cxt->mtd;
	192	size_t retlen;
	193	int ret;
4b23aff0	194
6ce0a856 RP	195	if (cxt->writecount < OOPS_PAGE_SIZE)
	196	memset(cxt->oops_buf + cxt->writecount, 0xff,
	197	OOPS_PAGE_SIZE - cxt->writecount);
	198
621e4f8e RP	199	if (panic)
	200	ret = mtd->panic_write(mtd, cxt->nextpage * OOPS_PAGE_SIZE,
	201	OOPS_PAGE_SIZE, &retlen, cxt->oops_buf);
	202	else
	203	ret = mtd->write(mtd, cxt->nextpage * OOPS_PAGE_SIZE,
6ce0a856 RP	204	OOPS_PAGE_SIZE, &retlen, cxt->oops_buf);
	205
	206	cxt->writecount = 0;
	207
	208	if ((retlen != OOPS_PAGE_SIZE) \|\| (ret < 0))
	209	printk(KERN_ERR "mtdoops: Write failure at %d (%td of %d written), err %d.\n",
	210	cxt->nextpage * OOPS_PAGE_SIZE, retlen, OOPS_PAGE_SIZE, ret);
	211
	212	mtdoops_inc_counter(cxt);
621e4f8e RP	213	}
	214
	215
	216	static void mtdoops_workfunc_write(struct work_struct *work)
	217	{
	218	struct mtdoops_context *cxt =
	219	container_of(work, struct mtdoops_context, work_write);
	220
	221	mtdoops_write(cxt, 0);
6ce0a856	222	}
4b23aff0	223
6ce0a856	224	static void find_next_position(struct mtdoops_context *cxt)
4b23aff0 RP	225	{
4b23aff0 RP	226	struct mtd_info *mtd = cxt->mtd;
2986bd2a	227	int ret, page, maxpos = 0;
f0482ee3	228	u32 count[2], maxcount = 0xffffffff;
4b23aff0 RP	229	size_t retlen;
	230
	231	for (page = 0; page < cxt->oops_pages; page++) {
f0482ee3 RP	232	ret = mtd->read(mtd, page * OOPS_PAGE_SIZE, 8, &retlen, (u_char *) &count[0]);
	233	if ((retlen != 8) \|\| ((ret < 0) && (ret != -EUCLEAN))) {
	234	printk(KERN_ERR "mtdoops: Read failure at %d (%td of 8 read)"
2986bd2a RP	235	", err %d.\n", page * OOPS_PAGE_SIZE, retlen, ret);
	236	continue;
	237	}
	238
f0482ee3 RP	239	if (count[1] != MTDOOPS_KERNMSG_MAGIC)
	240	continue;
	241	if (count[0] == 0xffffffff)
4b23aff0 RP	242	continue;
4b23aff0 RP	243	if (maxcount == 0xffffffff) {
f0482ee3	244	maxcount = count[0];
4b23aff0	245	maxpos = page;
f0482ee3 RP	246	} else if ((count[0] < 0x40000000) && (maxcount > 0xc0000000)) {
f0482ee3 RP	247	maxcount = count[0];
4b23aff0	248	maxpos = page;
f0482ee3 RP	249	} else if ((count[0] > maxcount) && (count[0] < 0xc0000000)) {
f0482ee3 RP	250	maxcount = count[0];
4b23aff0	251	maxpos = page;
f0482ee3	252	} else if ((count[0] > maxcount) && (count[0] > 0xc0000000)
4b23aff0	253	&& (maxcount > 0x80000000)) {
f0482ee3	254	maxcount = count[0];
4b23aff0 RP	255	maxpos = page;
	256	}
	257	}
	258	if (maxcount == 0xffffffff) {
	259	cxt->nextpage = 0;
	260	cxt->nextcount = 1;
43b5693d	261	schedule_work(&cxt->work_erase);
6ce0a856	262	return;
4b23aff0 RP	263	}
	264
	265	cxt->nextpage = maxpos;
	266	cxt->nextcount = maxcount;
	267
6ce0a856	268	mtdoops_inc_counter(cxt);
4b23aff0 RP	269	}
	270
	271
	272	static void mtdoops_notify_add(struct mtd_info *mtd)
	273	{
	274	struct mtdoops_context *cxt = &oops_cxt;
4b23aff0 RP	275
	276	if ((mtd->index != cxt->mtd_index) \|\| cxt->mtd_index < 0)
	277	return;
	278
	279	if (mtd->size < (mtd->erasesize * 2)) {
	280	printk(KERN_ERR "MTD partition %d not big enough for mtdoops\n",
	281	mtd->index);
	282	return;
	283	}
	284
79dcd8e9 RP	285	if (mtd->erasesize < OOPS_PAGE_SIZE) {
	286	printk(KERN_ERR "Eraseblock size of MTD partition %d too small\n",
	287	mtd->index);
	288	return;
	289	}
	290
4b23aff0	291	cxt->mtd = mtd;
69423d99 AH	292	if (mtd->size > INT_MAX)
	293	cxt->oops_pages = INT_MAX / OOPS_PAGE_SIZE;
	294	else
	295	cxt->oops_pages = (int)mtd->size / OOPS_PAGE_SIZE;
4b23aff0	296
6ce0a856	297	find_next_position(cxt);
4b23aff0	298
79dcd8e9	299	printk(KERN_INFO "mtdoops: Attached to MTD device %d\n", mtd->index);
4b23aff0 RP	300	}
	301
	302	static void mtdoops_notify_remove(struct mtd_info *mtd)
	303	{
	304	struct mtdoops_context *cxt = &oops_cxt;
	305
	306	if ((mtd->index != cxt->mtd_index) \|\| cxt->mtd_index < 0)
	307	return;
	308
	309	cxt->mtd = NULL;
	310	flush_scheduled_work();
	311	}
	312
8691a729	313	static void mtdoops_console_sync(void)
4b23aff0	314	{
8691a729	315	struct mtdoops_context *cxt = &oops_cxt;
4b23aff0	316	struct mtd_info *mtd = cxt->mtd;
47c152b8	317	unsigned long flags;
4b23aff0	318
6ce0a856	319	if (!cxt->ready \|\| !mtd \|\| cxt->writecount == 0)
4b23aff0 RP	320	return;
4b23aff0 RP	321
47c152b8 RP	322	/*
	323	* Once ready is 0 and we've held the lock no further writes to the
	324	* buffer will happen
	325	*/
	326	spin_lock_irqsave(&cxt->writecount_lock, flags);
	327	if (!cxt->ready) {
	328	spin_unlock_irqrestore(&cxt->writecount_lock, flags);
	329	return;
	330	}
8691a729	331	cxt->ready = 0;
47c152b8	332	spin_unlock_irqrestore(&cxt->writecount_lock, flags);
8691a729	333
621e4f8e RP	334	if (mtd->panic_write && in_interrupt())
	335	/* Interrupt context, we're going to panic so try and log */
	336	mtdoops_write(cxt, 1);
	337	else
	338	schedule_work(&cxt->work_write);
8691a729 RP	339	}
	340
	341	static void
	342	mtdoops_console_write(struct console co, const char s, unsigned int count)
	343	{
	344	struct mtdoops_context *cxt = co->data;
	345	struct mtd_info *mtd = cxt->mtd;
47c152b8	346	unsigned long flags;
8691a729 RP	347
	348	if (!oops_in_progress) {
	349	mtdoops_console_sync();
	350	return;
4b23aff0 RP	351	}
4b23aff0 RP	352
8691a729	353	if (!cxt->ready \|\| !mtd)
4b23aff0 RP	354	return;
4b23aff0 RP	355
47c152b8 RP	356	/* Locking on writecount ensures sequential writes to the buffer */
	357	spin_lock_irqsave(&cxt->writecount_lock, flags);
	358
	359	/* Check ready status didn't change whilst waiting for the lock */
	360	if (!cxt->ready)
	361	return;
	362
4b23aff0 RP	363	if (cxt->writecount == 0) {
4b23aff0 RP	364	u32 *stamp = cxt->oops_buf;
f0482ee3 RP	365	*stamp++ = cxt->nextcount;
	366	*stamp = MTDOOPS_KERNMSG_MAGIC;
	367	cxt->writecount = 8;
4b23aff0 RP	368	}
	369
	370	if ((count + cxt->writecount) > OOPS_PAGE_SIZE)
	371	count = OOPS_PAGE_SIZE - cxt->writecount;
	372
235d6200 PK	373	memcpy(cxt->oops_buf + cxt->writecount, s, count);
235d6200 PK	374	cxt->writecount += count;
47c152b8 RP	375
	376	spin_unlock_irqrestore(&cxt->writecount_lock, flags);
	377
	378	if (cxt->writecount == OOPS_PAGE_SIZE)
	379	mtdoops_console_sync();
4b23aff0 RP	380	}
	381
	382	static int __init mtdoops_console_setup(struct console co, char options)
	383	{
	384	struct mtdoops_context *cxt = co->data;
	385
	386	if (cxt->mtd_index != -1)
	387	return -EBUSY;
	388	if (co->index == -1)
	389	return -EINVAL;
	390
	391	cxt->mtd_index = co->index;
	392	return 0;
	393	}
	394
	395	static struct mtd_notifier mtdoops_notifier = {
	396	.add = mtdoops_notify_add,
	397	.remove = mtdoops_notify_remove,
	398	};
	399
	400	static struct console mtdoops_console = {
	401	.name = "ttyMTD",
	402	.write = mtdoops_console_write,
	403	.setup = mtdoops_console_setup,
8691a729	404	.unblank = mtdoops_console_sync,
4b23aff0 RP	405	.index = -1,
	406	.data = &oops_cxt,
	407	};
	408
	409	static int __init mtdoops_console_init(void)
	410	{
	411	struct mtdoops_context *cxt = &oops_cxt;
	412
	413	cxt->mtd_index = -1;
	414	cxt->oops_buf = vmalloc(OOPS_PAGE_SIZE);
	415
	416	if (!cxt->oops_buf) {
79dcd8e9	417	printk(KERN_ERR "Failed to allocate mtdoops buffer workspace\n");
4b23aff0 RP	418	return -ENOMEM;
	419	}
	420
6ce0a856 RP	421	INIT_WORK(&cxt->work_erase, mtdoops_workfunc_erase);
6ce0a856 RP	422	INIT_WORK(&cxt->work_write, mtdoops_workfunc_write);
4b23aff0 RP	423
	424	register_console(&mtdoops_console);
	425	register_mtd_user(&mtdoops_notifier);
	426	return 0;
	427	}
	428
	429	static void __exit mtdoops_console_exit(void)
	430	{
	431	struct mtdoops_context *cxt = &oops_cxt;
	432
	433	unregister_mtd_user(&mtdoops_notifier);
	434	unregister_console(&mtdoops_console);
	435	vfree(cxt->oops_buf);
	436	}
	437
	438
	439	subsys_initcall(mtdoops_console_init);
	440	module_exit(mtdoops_console_exit);
	441
	442	MODULE_LICENSE("GPL");
	443	MODULE_AUTHOR("Richard Purdie <rpurdie@openedhand.com>");
	444	MODULE_DESCRIPTION("MTD Oops/Panic console logger/driver");