[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 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%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>
f9f7dd22	33	#include <linux/interrupt.h>
4b23aff0 RP	34	#include <linux/mtd/mtd.h>
	35
	36	#define OOPS_PAGE_SIZE 4096
	37
7903cbab	38	static struct mtdoops_context {
4b23aff0	39	int mtd_index;
6ce0a856 RP	40	struct work_struct work_erase;
6ce0a856 RP	41	struct work_struct work_write;
4b23aff0 RP	42	struct mtd_info *mtd;
	43	int oops_pages;
	44	int nextpage;
	45	int nextcount;
	46
	47	void *oops_buf;
47c152b8 RP	48
	49	/* writecount and disabling ready are spin lock protected */
	50	spinlock_t writecount_lock;
4b23aff0 RP	51	int ready;
	52	int writecount;
	53	} oops_cxt;
	54
	55	static void mtdoops_erase_callback(struct erase_info *done)
	56	{
	57	wait_queue_head_t wait_q = (wait_queue_head_t )done->priv;
	58	wake_up(wait_q);
	59	}
	60
	61	static int mtdoops_erase_block(struct mtd_info *mtd, int offset)
	62	{
	63	struct erase_info erase;
	64	DECLARE_WAITQUEUE(wait, current);
	65	wait_queue_head_t wait_q;
	66	int ret;
	67
	68	init_waitqueue_head(&wait_q);
	69	erase.mtd = mtd;
	70	erase.callback = mtdoops_erase_callback;
	71	erase.addr = offset;
79dcd8e9	72	erase.len = mtd->erasesize;
4b23aff0 RP	73	erase.priv = (u_long)&wait_q;
	74
	75	set_current_state(TASK_INTERRUPTIBLE);
	76	add_wait_queue(&wait_q, &wait);
	77
	78	ret = mtd->erase(mtd, &erase);
	79	if (ret) {
	80	set_current_state(TASK_RUNNING);
	81	remove_wait_queue(&wait_q, &wait);
	82	printk (KERN_WARNING "mtdoops: erase of region [0x%x, 0x%x] "
	83	"on \"%s\" failed\n",
	84	erase.addr, erase.len, mtd->name);
	85	return ret;
	86	}
	87
	88	schedule(); /* Wait for erase to finish. */
	89	remove_wait_queue(&wait_q, &wait);
	90
	91	return 0;
	92	}
	93
6ce0a856	94	static void mtdoops_inc_counter(struct mtdoops_context *cxt)
4b23aff0 RP	95	{
	96	struct mtd_info *mtd = cxt->mtd;
	97	size_t retlen;
	98	u32 count;
	99	int ret;
	100
	101	cxt->nextpage++;
	102	if (cxt->nextpage > cxt->oops_pages)
	103	cxt->nextpage = 0;
	104	cxt->nextcount++;
	105	if (cxt->nextcount == 0xffffffff)
	106	cxt->nextcount = 0;
	107
	108	ret = mtd->read(mtd, cxt->nextpage * OOPS_PAGE_SIZE, 4,
	109	&retlen, (u_char *) &count);
2986bd2a	110	if ((retlen != 4) \|\| ((ret < 0) && (ret != -EUCLEAN))) {
68d09b1b	111	printk(KERN_ERR "mtdoops: Read failure at %d (%td of 4 read)"
4b23aff0 RP	112	", err %d.\n", cxt->nextpage * OOPS_PAGE_SIZE,
4b23aff0 RP	113	retlen, ret);
6ce0a856 RP	114	schedule_work(&cxt->work_erase);
6ce0a856 RP	115	return;
4b23aff0 RP	116	}
	117
	118	/* See if we need to erase the next block */
6ce0a856 RP	119	if (count != 0xffffffff) {
	120	schedule_work(&cxt->work_erase);
	121	return;
	122	}
4b23aff0 RP	123
	124	printk(KERN_DEBUG "mtdoops: Ready %d, %d (no erase)\n",
	125	cxt->nextpage, cxt->nextcount);
	126	cxt->ready = 1;
4b23aff0 RP	127	}
4b23aff0 RP	128
6ce0a856 RP	129	/* Scheduled work - when we can't proceed without erasing a block */
6ce0a856 RP	130	static void mtdoops_workfunc_erase(struct work_struct *work)
4b23aff0	131	{
6ce0a856 RP	132	struct mtdoops_context *cxt =
6ce0a856 RP	133	container_of(work, struct mtdoops_context, work_erase);
4b23aff0 RP	134	struct mtd_info *mtd = cxt->mtd;
	135	int i = 0, j, ret, mod;
	136
	137	/* We were unregistered */
	138	if (!mtd)
	139	return;
	140
	141	mod = (cxt->nextpage * OOPS_PAGE_SIZE) % mtd->erasesize;
	142	if (mod != 0) {
	143	cxt->nextpage = cxt->nextpage + ((mtd->erasesize - mod) / OOPS_PAGE_SIZE);
	144	if (cxt->nextpage > cxt->oops_pages)
	145	cxt->nextpage = 0;
	146	}
	147
2986bd2a RP	148	while (mtd->block_isbad) {
	149	ret = mtd->block_isbad(mtd, cxt->nextpage * OOPS_PAGE_SIZE);
	150	if (!ret)
	151	break;
	152	if (ret < 0) {
	153	printk(KERN_ERR "mtdoops: block_isbad failed, aborting.\n");
	154	return;
	155	}
4b23aff0 RP	156	badblock:
	157	printk(KERN_WARNING "mtdoops: Bad block at %08x\n",
	158	cxt->nextpage * OOPS_PAGE_SIZE);
	159	i++;
	160	cxt->nextpage = cxt->nextpage + (mtd->erasesize / OOPS_PAGE_SIZE);
	161	if (cxt->nextpage > cxt->oops_pages)
	162	cxt->nextpage = 0;
	163	if (i == (cxt->oops_pages / (mtd->erasesize / OOPS_PAGE_SIZE))) {
	164	printk(KERN_ERR "mtdoops: All blocks bad!\n");
	165	return;
	166	}
	167	}
	168
	169	for (j = 0, ret = -1; (j < 3) && (ret < 0); j++)
	170	ret = mtdoops_erase_block(mtd, cxt->nextpage * OOPS_PAGE_SIZE);
	171
2986bd2a RP	172	if (ret >= 0) {
	173	printk(KERN_DEBUG "mtdoops: Ready %d, %d \n", cxt->nextpage, cxt->nextcount);
	174	cxt->ready = 1;
	175	return;
4b23aff0 RP	176	}
4b23aff0 RP	177
2986bd2a RP	178	if (mtd->block_markbad && (ret == -EIO)) {
	179	ret = mtd->block_markbad(mtd, cxt->nextpage * OOPS_PAGE_SIZE);
	180	if (ret < 0) {
	181	printk(KERN_ERR "mtdoops: block_markbad failed, aborting.\n");
	182	return;
	183	}
	184	}
	185	goto badblock;
4b23aff0 RP	186	}
4b23aff0 RP	187
621e4f8e	188	static void mtdoops_write(struct mtdoops_context *cxt, int panic)
4b23aff0	189	{
6ce0a856 RP	190	struct mtd_info *mtd = cxt->mtd;
	191	size_t retlen;
	192	int ret;
4b23aff0	193
6ce0a856 RP	194	if (cxt->writecount < OOPS_PAGE_SIZE)
	195	memset(cxt->oops_buf + cxt->writecount, 0xff,
	196	OOPS_PAGE_SIZE - cxt->writecount);
	197
621e4f8e RP	198	if (panic)
	199	ret = mtd->panic_write(mtd, cxt->nextpage * OOPS_PAGE_SIZE,
	200	OOPS_PAGE_SIZE, &retlen, cxt->oops_buf);
	201	else
	202	ret = mtd->write(mtd, cxt->nextpage * OOPS_PAGE_SIZE,
6ce0a856 RP	203	OOPS_PAGE_SIZE, &retlen, cxt->oops_buf);
	204
	205	cxt->writecount = 0;
	206
	207	if ((retlen != OOPS_PAGE_SIZE) \|\| (ret < 0))
	208	printk(KERN_ERR "mtdoops: Write failure at %d (%td of %d written), err %d.\n",
	209	cxt->nextpage * OOPS_PAGE_SIZE, retlen, OOPS_PAGE_SIZE, ret);
	210
	211	mtdoops_inc_counter(cxt);
621e4f8e RP	212	}
	213
	214
	215	static void mtdoops_workfunc_write(struct work_struct *work)
	216	{
	217	struct mtdoops_context *cxt =
	218	container_of(work, struct mtdoops_context, work_write);
	219
	220	mtdoops_write(cxt, 0);
6ce0a856	221	}
4b23aff0	222
6ce0a856	223	static void find_next_position(struct mtdoops_context *cxt)
4b23aff0 RP	224	{
4b23aff0 RP	225	struct mtd_info *mtd = cxt->mtd;
2986bd2a	226	int ret, page, maxpos = 0;
4b23aff0 RP	227	u32 count, maxcount = 0xffffffff;
	228	size_t retlen;
	229
	230	for (page = 0; page < cxt->oops_pages; page++) {
2986bd2a RP	231	ret = mtd->read(mtd, page * OOPS_PAGE_SIZE, 4, &retlen, (u_char *) &count);
	232	if ((retlen != 4) \|\| ((ret < 0) && (ret != -EUCLEAN))) {
	233	printk(KERN_ERR "mtdoops: Read failure at %d (%td of 4 read)"
	234	", err %d.\n", page * OOPS_PAGE_SIZE, retlen, ret);
	235	continue;
	236	}
	237
4b23aff0 RP	238	if (count == 0xffffffff)
	239	continue;
	240	if (maxcount == 0xffffffff) {
	241	maxcount = count;
	242	maxpos = page;
	243	} else if ((count < 0x40000000) && (maxcount > 0xc0000000)) {
	244	maxcount = count;
	245	maxpos = page;
	246	} else if ((count > maxcount) && (count < 0xc0000000)) {
	247	maxcount = count;
	248	maxpos = page;
	249	} else if ((count > maxcount) && (count > 0xc0000000)
	250	&& (maxcount > 0x80000000)) {
	251	maxcount = count;
	252	maxpos = page;
	253	}
	254	}
	255	if (maxcount == 0xffffffff) {
	256	cxt->nextpage = 0;
	257	cxt->nextcount = 1;
	258	cxt->ready = 1;
	259	printk(KERN_DEBUG "mtdoops: Ready %d, %d (first init)\n",
	260	cxt->nextpage, cxt->nextcount);
6ce0a856	261	return;
4b23aff0 RP	262	}
	263
	264	cxt->nextpage = maxpos;
	265	cxt->nextcount = maxcount;
	266
6ce0a856	267	mtdoops_inc_counter(cxt);
4b23aff0 RP	268	}
	269
	270
	271	static void mtdoops_notify_add(struct mtd_info *mtd)
	272	{
	273	struct mtdoops_context *cxt = &oops_cxt;
4b23aff0 RP	274
	275	if ((mtd->index != cxt->mtd_index) \|\| cxt->mtd_index < 0)
	276	return;
	277
	278	if (mtd->size < (mtd->erasesize * 2)) {
	279	printk(KERN_ERR "MTD partition %d not big enough for mtdoops\n",
	280	mtd->index);
	281	return;
	282	}
	283
79dcd8e9 RP	284	if (mtd->erasesize < OOPS_PAGE_SIZE) {
	285	printk(KERN_ERR "Eraseblock size of MTD partition %d too small\n",
	286	mtd->index);
	287	return;
	288	}
	289
4b23aff0 RP	290	cxt->mtd = mtd;
	291	cxt->oops_pages = mtd->size / OOPS_PAGE_SIZE;
	292
6ce0a856	293	find_next_position(cxt);
4b23aff0	294
79dcd8e9	295	printk(KERN_INFO "mtdoops: Attached to MTD device %d\n", mtd->index);
4b23aff0 RP	296	}
	297
	298	static void mtdoops_notify_remove(struct mtd_info *mtd)
	299	{
	300	struct mtdoops_context *cxt = &oops_cxt;
	301
	302	if ((mtd->index != cxt->mtd_index) \|\| cxt->mtd_index < 0)
	303	return;
	304
	305	cxt->mtd = NULL;
	306	flush_scheduled_work();
	307	}
	308
8691a729	309	static void mtdoops_console_sync(void)
4b23aff0	310	{
8691a729	311	struct mtdoops_context *cxt = &oops_cxt;
4b23aff0	312	struct mtd_info *mtd = cxt->mtd;
47c152b8	313	unsigned long flags;
4b23aff0	314
6ce0a856	315	if (!cxt->ready \|\| !mtd \|\| cxt->writecount == 0)
4b23aff0 RP	316	return;
4b23aff0 RP	317
47c152b8 RP	318	/*
	319	* Once ready is 0 and we've held the lock no further writes to the
	320	* buffer will happen
	321	*/
	322	spin_lock_irqsave(&cxt->writecount_lock, flags);
	323	if (!cxt->ready) {
	324	spin_unlock_irqrestore(&cxt->writecount_lock, flags);
	325	return;
	326	}
8691a729	327	cxt->ready = 0;
47c152b8	328	spin_unlock_irqrestore(&cxt->writecount_lock, flags);
8691a729	329
621e4f8e RP	330	if (mtd->panic_write && in_interrupt())
	331	/* Interrupt context, we're going to panic so try and log */
	332	mtdoops_write(cxt, 1);
	333	else
	334	schedule_work(&cxt->work_write);
8691a729 RP	335	}
	336
	337	static void
	338	mtdoops_console_write(struct console co, const char s, unsigned int count)
	339	{
	340	struct mtdoops_context *cxt = co->data;
	341	struct mtd_info *mtd = cxt->mtd;
47c152b8	342	unsigned long flags;
8691a729 RP	343
	344	if (!oops_in_progress) {
	345	mtdoops_console_sync();
	346	return;
4b23aff0 RP	347	}
4b23aff0 RP	348
8691a729	349	if (!cxt->ready \|\| !mtd)
4b23aff0 RP	350	return;
4b23aff0 RP	351
47c152b8 RP	352	/* Locking on writecount ensures sequential writes to the buffer */
	353	spin_lock_irqsave(&cxt->writecount_lock, flags);
	354
	355	/* Check ready status didn't change whilst waiting for the lock */
	356	if (!cxt->ready)
	357	return;
	358
4b23aff0 RP	359	if (cxt->writecount == 0) {
	360	u32 *stamp = cxt->oops_buf;
	361	*stamp = cxt->nextcount;
	362	cxt->writecount = 4;
	363	}
	364
	365	if ((count + cxt->writecount) > OOPS_PAGE_SIZE)
	366	count = OOPS_PAGE_SIZE - cxt->writecount;
	367
235d6200 PK	368	memcpy(cxt->oops_buf + cxt->writecount, s, count);
235d6200 PK	369	cxt->writecount += count;
47c152b8 RP	370
	371	spin_unlock_irqrestore(&cxt->writecount_lock, flags);
	372
	373	if (cxt->writecount == OOPS_PAGE_SIZE)
	374	mtdoops_console_sync();
4b23aff0 RP	375	}
	376
	377	static int __init mtdoops_console_setup(struct console co, char options)
	378	{
	379	struct mtdoops_context *cxt = co->data;
	380
	381	if (cxt->mtd_index != -1)
	382	return -EBUSY;
	383	if (co->index == -1)
	384	return -EINVAL;
	385
	386	cxt->mtd_index = co->index;
	387	return 0;
	388	}
	389
	390	static struct mtd_notifier mtdoops_notifier = {
	391	.add = mtdoops_notify_add,
	392	.remove = mtdoops_notify_remove,
	393	};
	394
	395	static struct console mtdoops_console = {
	396	.name = "ttyMTD",
	397	.write = mtdoops_console_write,
	398	.setup = mtdoops_console_setup,
8691a729	399	.unblank = mtdoops_console_sync,
4b23aff0 RP	400	.index = -1,
	401	.data = &oops_cxt,
	402	};
	403
	404	static int __init mtdoops_console_init(void)
	405	{
	406	struct mtdoops_context *cxt = &oops_cxt;
	407
	408	cxt->mtd_index = -1;
	409	cxt->oops_buf = vmalloc(OOPS_PAGE_SIZE);
	410
	411	if (!cxt->oops_buf) {
79dcd8e9	412	printk(KERN_ERR "Failed to allocate mtdoops buffer workspace\n");
4b23aff0 RP	413	return -ENOMEM;
	414	}
	415
6ce0a856 RP	416	INIT_WORK(&cxt->work_erase, mtdoops_workfunc_erase);
6ce0a856 RP	417	INIT_WORK(&cxt->work_write, mtdoops_workfunc_write);
4b23aff0 RP	418
	419	register_console(&mtdoops_console);
	420	register_mtd_user(&mtdoops_notifier);
	421	return 0;
	422	}
	423
	424	static void __exit mtdoops_console_exit(void)
	425	{
	426	struct mtdoops_context *cxt = &oops_cxt;
	427
	428	unregister_mtd_user(&mtdoops_notifier);
	429	unregister_console(&mtdoops_console);
	430	vfree(cxt->oops_buf);
	431	}
	432
	433
	434	subsys_initcall(mtdoops_console_init);
	435	module_exit(mtdoops_console_exit);
	436
	437	MODULE_LICENSE("GPL");
	438	MODULE_AUTHOR("Richard Purdie <rpurdie@openedhand.com>");
	439	MODULE_DESCRIPTION("MTD Oops/Panic console logger/driver");