ClabureDB: Classified Bug-Reports Database

  /*
   * 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%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[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;
        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;
                *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");