linux/drivers/mtd/mtdoops.c

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/*
* 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");