[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/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_workfunc_write(struct work_struct *work)
{
	struct mtdoops_context *cxt =
			container_of(work, struct mtdoops_context, work_write);
	struct mtd_info *mtd = cxt->mtd;
	size_t retlen;
	int ret;

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

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

	cxt->writecount = 0;

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

	mtdoops_inc_counter(cxt);
}					

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

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

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

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

	mtdoops_inc_counter(cxt);
}


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

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

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

	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);

	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>
47c152b8	31	#include <linux/spinlock.h>
4b23aff0 RP	32	#include <linux/mtd/mtd.h>
	33
	34	#define OOPS_PAGE_SIZE 4096
	35
6ce0a856	36	struct mtdoops_context {
4b23aff0	37	int mtd_index;
6ce0a856 RP	38	struct work_struct work_erase;
6ce0a856 RP	39	struct work_struct work_write;
4b23aff0 RP	40	struct mtd_info *mtd;
	41	int oops_pages;
	42	int nextpage;
	43	int nextcount;
	44
	45	void *oops_buf;
47c152b8 RP	46
	47	/* writecount and disabling ready are spin lock protected */
	48	spinlock_t writecount_lock;
4b23aff0 RP	49	int ready;
	50	int writecount;
	51	} oops_cxt;
	52
	53	static void mtdoops_erase_callback(struct erase_info *done)
	54	{
	55	wait_queue_head_t wait_q = (wait_queue_head_t )done->priv;
	56	wake_up(wait_q);
	57	}
	58
	59	static int mtdoops_erase_block(struct mtd_info *mtd, int offset)
	60	{
	61	struct erase_info erase;
	62	DECLARE_WAITQUEUE(wait, current);
	63	wait_queue_head_t wait_q;
	64	int ret;
	65
	66	init_waitqueue_head(&wait_q);
	67	erase.mtd = mtd;
	68	erase.callback = mtdoops_erase_callback;
	69	erase.addr = offset;
79dcd8e9	70	erase.len = mtd->erasesize;
4b23aff0 RP	71	erase.priv = (u_long)&wait_q;
	72
	73	set_current_state(TASK_INTERRUPTIBLE);
	74	add_wait_queue(&wait_q, &wait);
	75
	76	ret = mtd->erase(mtd, &erase);
	77	if (ret) {
	78	set_current_state(TASK_RUNNING);
	79	remove_wait_queue(&wait_q, &wait);
	80	printk (KERN_WARNING "mtdoops: erase of region [0x%x, 0x%x] "
	81	"on \"%s\" failed\n",
	82	erase.addr, erase.len, mtd->name);
	83	return ret;
	84	}
	85
	86	schedule(); /* Wait for erase to finish. */
	87	remove_wait_queue(&wait_q, &wait);
	88
	89	return 0;
	90	}
	91
6ce0a856	92	static void mtdoops_inc_counter(struct mtdoops_context *cxt)
4b23aff0 RP	93	{
	94	struct mtd_info *mtd = cxt->mtd;
	95	size_t retlen;
	96	u32 count;
	97	int ret;
	98
	99	cxt->nextpage++;
	100	if (cxt->nextpage > cxt->oops_pages)
	101	cxt->nextpage = 0;
	102	cxt->nextcount++;
	103	if (cxt->nextcount == 0xffffffff)
	104	cxt->nextcount = 0;
	105
	106	ret = mtd->read(mtd, cxt->nextpage * OOPS_PAGE_SIZE, 4,
	107	&retlen, (u_char *) &count);
2986bd2a	108	if ((retlen != 4) \|\| ((ret < 0) && (ret != -EUCLEAN))) {
68d09b1b	109	printk(KERN_ERR "mtdoops: Read failure at %d (%td of 4 read)"
4b23aff0 RP	110	", err %d.\n", cxt->nextpage * OOPS_PAGE_SIZE,
4b23aff0 RP	111	retlen, ret);
6ce0a856 RP	112	schedule_work(&cxt->work_erase);
6ce0a856 RP	113	return;
4b23aff0 RP	114	}
	115
	116	/* See if we need to erase the next block */
6ce0a856 RP	117	if (count != 0xffffffff) {
	118	schedule_work(&cxt->work_erase);
	119	return;
	120	}
4b23aff0 RP	121
	122	printk(KERN_DEBUG "mtdoops: Ready %d, %d (no erase)\n",
	123	cxt->nextpage, cxt->nextcount);
	124	cxt->ready = 1;
4b23aff0 RP	125	}
4b23aff0 RP	126
6ce0a856 RP	127	/* Scheduled work - when we can't proceed without erasing a block */
6ce0a856 RP	128	static void mtdoops_workfunc_erase(struct work_struct *work)
4b23aff0	129	{
6ce0a856 RP	130	struct mtdoops_context *cxt =
6ce0a856 RP	131	container_of(work, struct mtdoops_context, work_erase);
4b23aff0 RP	132	struct mtd_info *mtd = cxt->mtd;
	133	int i = 0, j, ret, mod;
	134
	135	/* We were unregistered */
	136	if (!mtd)
	137	return;
	138
	139	mod = (cxt->nextpage * OOPS_PAGE_SIZE) % mtd->erasesize;
	140	if (mod != 0) {
	141	cxt->nextpage = cxt->nextpage + ((mtd->erasesize - mod) / OOPS_PAGE_SIZE);
	142	if (cxt->nextpage > cxt->oops_pages)
	143	cxt->nextpage = 0;
	144	}
	145
2986bd2a RP	146	while (mtd->block_isbad) {
	147	ret = mtd->block_isbad(mtd, cxt->nextpage * OOPS_PAGE_SIZE);
	148	if (!ret)
	149	break;
	150	if (ret < 0) {
	151	printk(KERN_ERR "mtdoops: block_isbad failed, aborting.\n");
	152	return;
	153	}
4b23aff0 RP	154	badblock:
	155	printk(KERN_WARNING "mtdoops: Bad block at %08x\n",
	156	cxt->nextpage * OOPS_PAGE_SIZE);
	157	i++;
	158	cxt->nextpage = cxt->nextpage + (mtd->erasesize / OOPS_PAGE_SIZE);
	159	if (cxt->nextpage > cxt->oops_pages)
	160	cxt->nextpage = 0;
	161	if (i == (cxt->oops_pages / (mtd->erasesize / OOPS_PAGE_SIZE))) {
	162	printk(KERN_ERR "mtdoops: All blocks bad!\n");
	163	return;
	164	}
	165	}
	166
	167	for (j = 0, ret = -1; (j < 3) && (ret < 0); j++)
	168	ret = mtdoops_erase_block(mtd, cxt->nextpage * OOPS_PAGE_SIZE);
	169
2986bd2a RP	170	if (ret >= 0) {
	171	printk(KERN_DEBUG "mtdoops: Ready %d, %d \n", cxt->nextpage, cxt->nextcount);
	172	cxt->ready = 1;
	173	return;
4b23aff0 RP	174	}
4b23aff0 RP	175
2986bd2a RP	176	if (mtd->block_markbad && (ret == -EIO)) {
	177	ret = mtd->block_markbad(mtd, cxt->nextpage * OOPS_PAGE_SIZE);
	178	if (ret < 0) {
	179	printk(KERN_ERR "mtdoops: block_markbad failed, aborting.\n");
	180	return;
	181	}
	182	}
	183	goto badblock;
4b23aff0 RP	184	}
4b23aff0 RP	185
6ce0a856	186	static void mtdoops_workfunc_write(struct work_struct *work)
4b23aff0 RP	187	{
4b23aff0 RP	188	struct mtdoops_context *cxt =
6ce0a856 RP	189	container_of(work, struct mtdoops_context, work_write);
	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
	198	ret = mtd->write(mtd, cxt->nextpage * OOPS_PAGE_SIZE,
	199	OOPS_PAGE_SIZE, &retlen, cxt->oops_buf);
	200
	201	cxt->writecount = 0;
	202
	203	if ((retlen != OOPS_PAGE_SIZE) \|\| (ret < 0))
	204	printk(KERN_ERR "mtdoops: Write failure at %d (%td of %d written), err %d.\n",
	205	cxt->nextpage * OOPS_PAGE_SIZE, retlen, OOPS_PAGE_SIZE, ret);
	206
	207	mtdoops_inc_counter(cxt);
	208	}
4b23aff0	209
6ce0a856	210	static void find_next_position(struct mtdoops_context *cxt)
4b23aff0 RP	211	{
4b23aff0 RP	212	struct mtd_info *mtd = cxt->mtd;
2986bd2a	213	int ret, page, maxpos = 0;
4b23aff0 RP	214	u32 count, maxcount = 0xffffffff;
	215	size_t retlen;
	216
	217	for (page = 0; page < cxt->oops_pages; page++) {
2986bd2a RP	218	ret = mtd->read(mtd, page * OOPS_PAGE_SIZE, 4, &retlen, (u_char *) &count);
	219	if ((retlen != 4) \|\| ((ret < 0) && (ret != -EUCLEAN))) {
	220	printk(KERN_ERR "mtdoops: Read failure at %d (%td of 4 read)"
	221	", err %d.\n", page * OOPS_PAGE_SIZE, retlen, ret);
	222	continue;
	223	}
	224
4b23aff0 RP	225	if (count == 0xffffffff)
	226	continue;
	227	if (maxcount == 0xffffffff) {
	228	maxcount = count;
	229	maxpos = page;
	230	} else if ((count < 0x40000000) && (maxcount > 0xc0000000)) {
	231	maxcount = count;
	232	maxpos = page;
	233	} else if ((count > maxcount) && (count < 0xc0000000)) {
	234	maxcount = count;
	235	maxpos = page;
	236	} else if ((count > maxcount) && (count > 0xc0000000)
	237	&& (maxcount > 0x80000000)) {
	238	maxcount = count;
	239	maxpos = page;
	240	}
	241	}
	242	if (maxcount == 0xffffffff) {
	243	cxt->nextpage = 0;
	244	cxt->nextcount = 1;
	245	cxt->ready = 1;
	246	printk(KERN_DEBUG "mtdoops: Ready %d, %d (first init)\n",
	247	cxt->nextpage, cxt->nextcount);
6ce0a856	248	return;
4b23aff0 RP	249	}
	250
	251	cxt->nextpage = maxpos;
	252	cxt->nextcount = maxcount;
	253
6ce0a856	254	mtdoops_inc_counter(cxt);
4b23aff0 RP	255	}
	256
	257
	258	static void mtdoops_notify_add(struct mtd_info *mtd)
	259	{
	260	struct mtdoops_context *cxt = &oops_cxt;
4b23aff0 RP	261
	262	if ((mtd->index != cxt->mtd_index) \|\| cxt->mtd_index < 0)
	263	return;
	264
	265	if (mtd->size < (mtd->erasesize * 2)) {
	266	printk(KERN_ERR "MTD partition %d not big enough for mtdoops\n",
	267	mtd->index);
	268	return;
	269	}
	270
79dcd8e9 RP	271	if (mtd->erasesize < OOPS_PAGE_SIZE) {
	272	printk(KERN_ERR "Eraseblock size of MTD partition %d too small\n",
	273	mtd->index);
	274	return;
	275	}
	276
4b23aff0 RP	277	cxt->mtd = mtd;
	278	cxt->oops_pages = mtd->size / OOPS_PAGE_SIZE;
	279
6ce0a856	280	find_next_position(cxt);
4b23aff0	281
79dcd8e9	282	printk(KERN_INFO "mtdoops: Attached to MTD device %d\n", mtd->index);
4b23aff0 RP	283	}
	284
	285	static void mtdoops_notify_remove(struct mtd_info *mtd)
	286	{
	287	struct mtdoops_context *cxt = &oops_cxt;
	288
	289	if ((mtd->index != cxt->mtd_index) \|\| cxt->mtd_index < 0)
	290	return;
	291
	292	cxt->mtd = NULL;
	293	flush_scheduled_work();
	294	}
	295
8691a729	296	static void mtdoops_console_sync(void)
4b23aff0	297	{
8691a729	298	struct mtdoops_context *cxt = &oops_cxt;
4b23aff0	299	struct mtd_info *mtd = cxt->mtd;
47c152b8	300	unsigned long flags;
4b23aff0	301
6ce0a856	302	if (!cxt->ready \|\| !mtd \|\| cxt->writecount == 0)
4b23aff0 RP	303	return;
4b23aff0 RP	304
47c152b8 RP	305	/*
	306	* Once ready is 0 and we've held the lock no further writes to the
	307	* buffer will happen
	308	*/
	309	spin_lock_irqsave(&cxt->writecount_lock, flags);
	310	if (!cxt->ready) {
	311	spin_unlock_irqrestore(&cxt->writecount_lock, flags);
	312	return;
	313	}
8691a729	314	cxt->ready = 0;
47c152b8	315	spin_unlock_irqrestore(&cxt->writecount_lock, flags);
8691a729	316
6ce0a856	317	schedule_work(&cxt->work_write);
8691a729 RP	318	}
	319
	320	static void
	321	mtdoops_console_write(struct console co, const char s, unsigned int count)
	322	{
	323	struct mtdoops_context *cxt = co->data;
	324	struct mtd_info *mtd = cxt->mtd;
47c152b8	325	unsigned long flags;
8691a729 RP	326
	327	if (!oops_in_progress) {
	328	mtdoops_console_sync();
	329	return;
4b23aff0 RP	330	}
4b23aff0 RP	331
8691a729	332	if (!cxt->ready \|\| !mtd)
4b23aff0 RP	333	return;
4b23aff0 RP	334
47c152b8 RP	335	/* Locking on writecount ensures sequential writes to the buffer */
	336	spin_lock_irqsave(&cxt->writecount_lock, flags);
	337
	338	/* Check ready status didn't change whilst waiting for the lock */
	339	if (!cxt->ready)
	340	return;
	341
4b23aff0 RP	342	if (cxt->writecount == 0) {
	343	u32 *stamp = cxt->oops_buf;
	344	*stamp = cxt->nextcount;
	345	cxt->writecount = 4;
	346	}
	347
	348	if ((count + cxt->writecount) > OOPS_PAGE_SIZE)
	349	count = OOPS_PAGE_SIZE - cxt->writecount;
	350
235d6200 PK	351	memcpy(cxt->oops_buf + cxt->writecount, s, count);
235d6200 PK	352	cxt->writecount += count;
47c152b8 RP	353
	354	spin_unlock_irqrestore(&cxt->writecount_lock, flags);
	355
	356	if (cxt->writecount == OOPS_PAGE_SIZE)
	357	mtdoops_console_sync();
4b23aff0 RP	358	}
	359
	360	static int __init mtdoops_console_setup(struct console co, char options)
	361	{
	362	struct mtdoops_context *cxt = co->data;
	363
	364	if (cxt->mtd_index != -1)
	365	return -EBUSY;
	366	if (co->index == -1)
	367	return -EINVAL;
	368
	369	cxt->mtd_index = co->index;
	370	return 0;
	371	}
	372
	373	static struct mtd_notifier mtdoops_notifier = {
	374	.add = mtdoops_notify_add,
	375	.remove = mtdoops_notify_remove,
	376	};
	377
	378	static struct console mtdoops_console = {
	379	.name = "ttyMTD",
	380	.write = mtdoops_console_write,
	381	.setup = mtdoops_console_setup,
8691a729	382	.unblank = mtdoops_console_sync,
4b23aff0 RP	383	.index = -1,
	384	.data = &oops_cxt,
	385	};
	386
	387	static int __init mtdoops_console_init(void)
	388	{
	389	struct mtdoops_context *cxt = &oops_cxt;
	390
	391	cxt->mtd_index = -1;
	392	cxt->oops_buf = vmalloc(OOPS_PAGE_SIZE);
	393
	394	if (!cxt->oops_buf) {
79dcd8e9	395	printk(KERN_ERR "Failed to allocate mtdoops buffer workspace\n");
4b23aff0 RP	396	return -ENOMEM;
	397	}
	398
6ce0a856 RP	399	INIT_WORK(&cxt->work_erase, mtdoops_workfunc_erase);
6ce0a856 RP	400	INIT_WORK(&cxt->work_write, mtdoops_workfunc_write);
4b23aff0 RP	401
	402	register_console(&mtdoops_console);
	403	register_mtd_user(&mtdoops_notifier);
	404	return 0;
	405	}
	406
	407	static void __exit mtdoops_console_exit(void)
	408	{
	409	struct mtdoops_context *cxt = &oops_cxt;
	410
	411	unregister_mtd_user(&mtdoops_notifier);
	412	unregister_console(&mtdoops_console);
	413	vfree(cxt->oops_buf);
	414	}
	415
	416
	417	subsys_initcall(mtdoops_console_init);
	418	module_exit(mtdoops_console_exit);
	419
	420	MODULE_LICENSE("GPL");
	421	MODULE_AUTHOR("Richard Purdie <rpurdie@openedhand.com>");
	422	MODULE_DESCRIPTION("MTD Oops/Panic console logger/driver");