[mirror_ubuntu-hirsute-kernel.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/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;

	/* 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%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_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, 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;
	}

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

	cxt->mtd = mtd;
	cxt->oops_pages = 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;
		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;

	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>
4b23aff0 RP	33	#include <linux/mtd/mtd.h>
	34
	35	#define OOPS_PAGE_SIZE 4096
	36
6ce0a856	37	struct mtdoops_context {
4b23aff0	38	int mtd_index;
6ce0a856 RP	39	struct work_struct work_erase;
6ce0a856 RP	40	struct work_struct work_write;
4b23aff0 RP	41	struct mtd_info *mtd;
	42	int oops_pages;
	43	int nextpage;
	44	int nextcount;
	45
	46	void *oops_buf;
47c152b8 RP	47
	48	/* writecount and disabling ready are spin lock protected */
	49	spinlock_t writecount_lock;
4b23aff0 RP	50	int ready;
	51	int writecount;
	52	} oops_cxt;
	53
	54	static void mtdoops_erase_callback(struct erase_info *done)
	55	{
	56	wait_queue_head_t wait_q = (wait_queue_head_t )done->priv;
	57	wake_up(wait_q);
	58	}
	59
	60	static int mtdoops_erase_block(struct mtd_info *mtd, int offset)
	61	{
	62	struct erase_info erase;
	63	DECLARE_WAITQUEUE(wait, current);
	64	wait_queue_head_t wait_q;
	65	int ret;
	66
	67	init_waitqueue_head(&wait_q);
	68	erase.mtd = mtd;
	69	erase.callback = mtdoops_erase_callback;
	70	erase.addr = offset;
79dcd8e9	71	erase.len = mtd->erasesize;
4b23aff0 RP	72	erase.priv = (u_long)&wait_q;
	73
	74	set_current_state(TASK_INTERRUPTIBLE);
	75	add_wait_queue(&wait_q, &wait);
	76
	77	ret = mtd->erase(mtd, &erase);
	78	if (ret) {
	79	set_current_state(TASK_RUNNING);
	80	remove_wait_queue(&wait_q, &wait);
	81	printk (KERN_WARNING "mtdoops: erase of region [0x%x, 0x%x] "
	82	"on \"%s\" failed\n",
	83	erase.addr, erase.len, mtd->name);
	84	return ret;
	85	}
	86
	87	schedule(); /* Wait for erase to finish. */
	88	remove_wait_queue(&wait_q, &wait);
	89
	90	return 0;
	91	}
	92
6ce0a856	93	static void mtdoops_inc_counter(struct mtdoops_context *cxt)
4b23aff0 RP	94	{
	95	struct mtd_info *mtd = cxt->mtd;
	96	size_t retlen;
	97	u32 count;
	98	int ret;
	99
	100	cxt->nextpage++;
	101	if (cxt->nextpage > cxt->oops_pages)
	102	cxt->nextpage = 0;
	103	cxt->nextcount++;
	104	if (cxt->nextcount == 0xffffffff)
	105	cxt->nextcount = 0;
	106
	107	ret = mtd->read(mtd, cxt->nextpage * OOPS_PAGE_SIZE, 4,
	108	&retlen, (u_char *) &count);
2986bd2a	109	if ((retlen != 4) \|\| ((ret < 0) && (ret != -EUCLEAN))) {
68d09b1b	110	printk(KERN_ERR "mtdoops: Read failure at %d (%td of 4 read)"
4b23aff0 RP	111	", err %d.\n", cxt->nextpage * OOPS_PAGE_SIZE,
4b23aff0 RP	112	retlen, ret);
6ce0a856 RP	113	schedule_work(&cxt->work_erase);
6ce0a856 RP	114	return;
4b23aff0 RP	115	}
	116
	117	/* See if we need to erase the next block */
6ce0a856 RP	118	if (count != 0xffffffff) {
	119	schedule_work(&cxt->work_erase);
	120	return;
	121	}
4b23aff0 RP	122
	123	printk(KERN_DEBUG "mtdoops: Ready %d, %d (no erase)\n",
	124	cxt->nextpage, cxt->nextcount);
	125	cxt->ready = 1;
4b23aff0 RP	126	}
4b23aff0 RP	127
6ce0a856 RP	128	/* Scheduled work - when we can't proceed without erasing a block */
6ce0a856 RP	129	static void mtdoops_workfunc_erase(struct work_struct *work)
4b23aff0	130	{
6ce0a856 RP	131	struct mtdoops_context *cxt =
6ce0a856 RP	132	container_of(work, struct mtdoops_context, work_erase);
4b23aff0 RP	133	struct mtd_info *mtd = cxt->mtd;
	134	int i = 0, j, ret, mod;
	135
	136	/* We were unregistered */
	137	if (!mtd)
	138	return;
	139
	140	mod = (cxt->nextpage * OOPS_PAGE_SIZE) % mtd->erasesize;
	141	if (mod != 0) {
	142	cxt->nextpage = cxt->nextpage + ((mtd->erasesize - mod) / OOPS_PAGE_SIZE);
	143	if (cxt->nextpage > cxt->oops_pages)
	144	cxt->nextpage = 0;
	145	}
	146
2986bd2a RP	147	while (mtd->block_isbad) {
	148	ret = mtd->block_isbad(mtd, cxt->nextpage * OOPS_PAGE_SIZE);
	149	if (!ret)
	150	break;
	151	if (ret < 0) {
	152	printk(KERN_ERR "mtdoops: block_isbad failed, aborting.\n");
	153	return;
	154	}
4b23aff0 RP	155	badblock:
	156	printk(KERN_WARNING "mtdoops: Bad block at %08x\n",
	157	cxt->nextpage * OOPS_PAGE_SIZE);
	158	i++;
	159	cxt->nextpage = cxt->nextpage + (mtd->erasesize / OOPS_PAGE_SIZE);
	160	if (cxt->nextpage > cxt->oops_pages)
	161	cxt->nextpage = 0;
	162	if (i == (cxt->oops_pages / (mtd->erasesize / OOPS_PAGE_SIZE))) {
	163	printk(KERN_ERR "mtdoops: All blocks bad!\n");
	164	return;
	165	}
	166	}
	167
	168	for (j = 0, ret = -1; (j < 3) && (ret < 0); j++)
	169	ret = mtdoops_erase_block(mtd, cxt->nextpage * OOPS_PAGE_SIZE);
	170
2986bd2a RP	171	if (ret >= 0) {
	172	printk(KERN_DEBUG "mtdoops: Ready %d, %d \n", cxt->nextpage, cxt->nextcount);
	173	cxt->ready = 1;
	174	return;
4b23aff0 RP	175	}
4b23aff0 RP	176
2986bd2a RP	177	if (mtd->block_markbad && (ret == -EIO)) {
	178	ret = mtd->block_markbad(mtd, cxt->nextpage * OOPS_PAGE_SIZE);
	179	if (ret < 0) {
	180	printk(KERN_ERR "mtdoops: block_markbad failed, aborting.\n");
	181	return;
	182	}
	183	}
	184	goto badblock;
4b23aff0 RP	185	}
4b23aff0 RP	186
621e4f8e	187	static void mtdoops_write(struct mtdoops_context *cxt, int panic)
4b23aff0	188	{
6ce0a856 RP	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
621e4f8e RP	197	if (panic)
	198	ret = mtd->panic_write(mtd, cxt->nextpage * OOPS_PAGE_SIZE,
	199	OOPS_PAGE_SIZE, &retlen, cxt->oops_buf);
	200	else
	201	ret = mtd->write(mtd, cxt->nextpage * OOPS_PAGE_SIZE,
6ce0a856 RP	202	OOPS_PAGE_SIZE, &retlen, cxt->oops_buf);
	203
	204	cxt->writecount = 0;
	205
	206	if ((retlen != OOPS_PAGE_SIZE) \|\| (ret < 0))
	207	printk(KERN_ERR "mtdoops: Write failure at %d (%td of %d written), err %d.\n",
	208	cxt->nextpage * OOPS_PAGE_SIZE, retlen, OOPS_PAGE_SIZE, ret);
	209
	210	mtdoops_inc_counter(cxt);
621e4f8e RP	211	}
	212
	213
	214	static void mtdoops_workfunc_write(struct work_struct *work)
	215	{
	216	struct mtdoops_context *cxt =
	217	container_of(work, struct mtdoops_context, work_write);
	218
	219	mtdoops_write(cxt, 0);
6ce0a856	220	}
4b23aff0	221
6ce0a856	222	static void find_next_position(struct mtdoops_context *cxt)
4b23aff0 RP	223	{
4b23aff0 RP	224	struct mtd_info *mtd = cxt->mtd;
2986bd2a	225	int ret, page, maxpos = 0;
4b23aff0 RP	226	u32 count, maxcount = 0xffffffff;
	227	size_t retlen;
	228
	229	for (page = 0; page < cxt->oops_pages; page++) {
2986bd2a RP	230	ret = mtd->read(mtd, page * OOPS_PAGE_SIZE, 4, &retlen, (u_char *) &count);
	231	if ((retlen != 4) \|\| ((ret < 0) && (ret != -EUCLEAN))) {
	232	printk(KERN_ERR "mtdoops: Read failure at %d (%td of 4 read)"
	233	", err %d.\n", page * OOPS_PAGE_SIZE, retlen, ret);
	234	continue;
	235	}
	236
4b23aff0 RP	237	if (count == 0xffffffff)
	238	continue;
	239	if (maxcount == 0xffffffff) {
	240	maxcount = count;
	241	maxpos = page;
	242	} else if ((count < 0x40000000) && (maxcount > 0xc0000000)) {
	243	maxcount = count;
	244	maxpos = page;
	245	} else if ((count > maxcount) && (count < 0xc0000000)) {
	246	maxcount = count;
	247	maxpos = page;
	248	} else if ((count > maxcount) && (count > 0xc0000000)
	249	&& (maxcount > 0x80000000)) {
	250	maxcount = count;
	251	maxpos = page;
	252	}
	253	}
	254	if (maxcount == 0xffffffff) {
	255	cxt->nextpage = 0;
	256	cxt->nextcount = 1;
	257	cxt->ready = 1;
	258	printk(KERN_DEBUG "mtdoops: Ready %d, %d (first init)\n",
	259	cxt->nextpage, cxt->nextcount);
6ce0a856	260	return;
4b23aff0 RP	261	}
	262
	263	cxt->nextpage = maxpos;
	264	cxt->nextcount = maxcount;
	265
6ce0a856	266	mtdoops_inc_counter(cxt);
4b23aff0 RP	267	}
	268
	269
	270	static void mtdoops_notify_add(struct mtd_info *mtd)
	271	{
	272	struct mtdoops_context *cxt = &oops_cxt;
4b23aff0 RP	273
	274	if ((mtd->index != cxt->mtd_index) \|\| cxt->mtd_index < 0)
	275	return;
	276
	277	if (mtd->size < (mtd->erasesize * 2)) {
	278	printk(KERN_ERR "MTD partition %d not big enough for mtdoops\n",
	279	mtd->index);
	280	return;
	281	}
	282
79dcd8e9 RP	283	if (mtd->erasesize < OOPS_PAGE_SIZE) {
	284	printk(KERN_ERR "Eraseblock size of MTD partition %d too small\n",
	285	mtd->index);
	286	return;
	287	}
	288
4b23aff0 RP	289	cxt->mtd = mtd;
	290	cxt->oops_pages = mtd->size / OOPS_PAGE_SIZE;
	291
6ce0a856	292	find_next_position(cxt);
4b23aff0	293
79dcd8e9	294	printk(KERN_INFO "mtdoops: Attached to MTD device %d\n", mtd->index);
4b23aff0 RP	295	}
	296
	297	static void mtdoops_notify_remove(struct mtd_info *mtd)
	298	{
	299	struct mtdoops_context *cxt = &oops_cxt;
	300
	301	if ((mtd->index != cxt->mtd_index) \|\| cxt->mtd_index < 0)
	302	return;
	303
	304	cxt->mtd = NULL;
	305	flush_scheduled_work();
	306	}
	307
8691a729	308	static void mtdoops_console_sync(void)
4b23aff0	309	{
8691a729	310	struct mtdoops_context *cxt = &oops_cxt;
4b23aff0	311	struct mtd_info *mtd = cxt->mtd;
47c152b8	312	unsigned long flags;
4b23aff0	313
6ce0a856	314	if (!cxt->ready \|\| !mtd \|\| cxt->writecount == 0)
4b23aff0 RP	315	return;
4b23aff0 RP	316
47c152b8 RP	317	/*
	318	* Once ready is 0 and we've held the lock no further writes to the
	319	* buffer will happen
	320	*/
	321	spin_lock_irqsave(&cxt->writecount_lock, flags);
	322	if (!cxt->ready) {
	323	spin_unlock_irqrestore(&cxt->writecount_lock, flags);
	324	return;
	325	}
8691a729	326	cxt->ready = 0;
47c152b8	327	spin_unlock_irqrestore(&cxt->writecount_lock, flags);
8691a729	328
621e4f8e RP	329	if (mtd->panic_write && in_interrupt())
	330	/* Interrupt context, we're going to panic so try and log */
	331	mtdoops_write(cxt, 1);
	332	else
	333	schedule_work(&cxt->work_write);
8691a729 RP	334	}
	335
	336	static void
	337	mtdoops_console_write(struct console co, const char s, unsigned int count)
	338	{
	339	struct mtdoops_context *cxt = co->data;
	340	struct mtd_info *mtd = cxt->mtd;
47c152b8	341	unsigned long flags;
8691a729 RP	342
	343	if (!oops_in_progress) {
	344	mtdoops_console_sync();
	345	return;
4b23aff0 RP	346	}
4b23aff0 RP	347
8691a729	348	if (!cxt->ready \|\| !mtd)
4b23aff0 RP	349	return;
4b23aff0 RP	350
47c152b8 RP	351	/* Locking on writecount ensures sequential writes to the buffer */
	352	spin_lock_irqsave(&cxt->writecount_lock, flags);
	353
	354	/* Check ready status didn't change whilst waiting for the lock */
	355	if (!cxt->ready)
	356	return;
	357
4b23aff0 RP	358	if (cxt->writecount == 0) {
	359	u32 *stamp = cxt->oops_buf;
	360	*stamp = cxt->nextcount;
	361	cxt->writecount = 4;
	362	}
	363
	364	if ((count + cxt->writecount) > OOPS_PAGE_SIZE)
	365	count = OOPS_PAGE_SIZE - cxt->writecount;
	366
235d6200 PK	367	memcpy(cxt->oops_buf + cxt->writecount, s, count);
235d6200 PK	368	cxt->writecount += count;
47c152b8 RP	369
	370	spin_unlock_irqrestore(&cxt->writecount_lock, flags);
	371
	372	if (cxt->writecount == OOPS_PAGE_SIZE)
	373	mtdoops_console_sync();
4b23aff0 RP	374	}
	375
	376	static int __init mtdoops_console_setup(struct console co, char options)
	377	{
	378	struct mtdoops_context *cxt = co->data;
	379
	380	if (cxt->mtd_index != -1)
	381	return -EBUSY;
	382	if (co->index == -1)
	383	return -EINVAL;
	384
	385	cxt->mtd_index = co->index;
	386	return 0;
	387	}
	388
	389	static struct mtd_notifier mtdoops_notifier = {
	390	.add = mtdoops_notify_add,
	391	.remove = mtdoops_notify_remove,
	392	};
	393
	394	static struct console mtdoops_console = {
	395	.name = "ttyMTD",
	396	.write = mtdoops_console_write,
	397	.setup = mtdoops_console_setup,
8691a729	398	.unblank = mtdoops_console_sync,
4b23aff0 RP	399	.index = -1,
	400	.data = &oops_cxt,
	401	};
	402
	403	static int __init mtdoops_console_init(void)
	404	{
	405	struct mtdoops_context *cxt = &oops_cxt;
	406
	407	cxt->mtd_index = -1;
	408	cxt->oops_buf = vmalloc(OOPS_PAGE_SIZE);
	409
	410	if (!cxt->oops_buf) {
79dcd8e9	411	printk(KERN_ERR "Failed to allocate mtdoops buffer workspace\n");
4b23aff0 RP	412	return -ENOMEM;
	413	}
	414
6ce0a856 RP	415	INIT_WORK(&cxt->work_erase, mtdoops_workfunc_erase);
6ce0a856 RP	416	INIT_WORK(&cxt->work_write, mtdoops_workfunc_write);
4b23aff0 RP	417
	418	register_console(&mtdoops_console);
	419	register_mtd_user(&mtdoops_notifier);
	420	return 0;
	421	}
	422
	423	static void __exit mtdoops_console_exit(void)
	424	{
	425	struct mtdoops_context *cxt = &oops_cxt;
	426
	427	unregister_mtd_user(&mtdoops_notifier);
	428	unregister_console(&mtdoops_console);
	429	vfree(cxt->oops_buf);
	430	}
	431
	432
	433	subsys_initcall(mtdoops_console_init);
	434	module_exit(mtdoops_console_exit);
	435
	436	MODULE_LICENSE("GPL");
	437	MODULE_AUTHOR("Richard Purdie <rpurdie@openedhand.com>");
	438	MODULE_DESCRIPTION("MTD Oops/Panic console logger/driver");