misc: apanic: bad block handling
Tom Zhu [Mon, 21 Sep 2009 21:36:05 +0000 (16:36 -0500)]
Add bad block handling in apanic

Signed-off-by: Tom Zhu <ling.zhu@motorola.com>
Signed-off-by: San Mehat <san@google.com>

misc: apanic: Improved bad-block / watchdog handling

1. handle cases that there is no more good blocks
2. touch softlockup watchdog at the start of apanic
3. change unsigned char get_bb() to unsigned int get_bb()
4. return idx instead of rc2, to keep the previous written pages.

Signed-off-by: Tom Zhu <ling.zhu@motorola.com>
Signed-off-by: San Mehat <san@google.com>

drivers/misc/apanic.c

index 2f858be..f50881b 100644 (file)
@@ -54,8 +54,6 @@ struct panic_header {
        u32 threads_length;
 };
 
-#define CHECK_BB       0
-
 struct apanic_data {
        struct mtd_info         *mtd;
        struct panic_header     curr;
@@ -68,6 +66,72 @@ static struct apanic_data drv_ctx;
 static struct work_struct proc_removal_work;
 static DEFINE_MUTEX(drv_mutex);
 
+static unsigned int *apanic_bbt;
+static unsigned int apanic_erase_blocks;
+static unsigned int apanic_good_blocks;
+
+static void set_bb(unsigned int block, unsigned int *bbt)
+{
+       unsigned int flag = 1;
+
+       BUG_ON(block >= apanic_erase_blocks);
+
+       flag = flag << (block%32);
+       apanic_bbt[block/32] |= flag;
+       apanic_good_blocks--;
+}
+
+static unsigned int get_bb(unsigned int block, unsigned int *bbt)
+{
+       unsigned int flag;
+
+       BUG_ON(block >= apanic_erase_blocks);
+
+       flag = 1 << (block%32);
+       return apanic_bbt[block/32] & flag;
+}
+
+static void alloc_bbt(struct mtd_info *mtd, unsigned int *bbt)
+{
+       int bbt_size;
+       apanic_erase_blocks = (mtd->size)>>(mtd->erasesize_shift);
+       bbt_size = (apanic_erase_blocks+32)/32;
+
+       apanic_bbt = kmalloc(bbt_size*4, GFP_KERNEL);
+       memset(apanic_bbt, 0, bbt_size*4);
+       apanic_good_blocks = apanic_erase_blocks;
+}
+static void scan_bbt(struct mtd_info *mtd, unsigned int *bbt)
+{
+       int i;
+
+       for (i = 0; i < apanic_erase_blocks; i++) {
+               if (mtd->block_isbad(mtd, i*mtd->erasesize))
+                       set_bb(i, apanic_bbt);
+       }
+}
+
+#define APANIC_INVALID_OFFSET 0xFFFFFFFF
+
+static unsigned int phy_offset(struct mtd_info *mtd, unsigned int offset)
+{
+       unsigned int logic_block = offset>>(mtd->erasesize_shift);
+       unsigned int phy_block;
+       unsigned good_block = 0;
+
+       for (phy_block = 0; phy_block < apanic_erase_blocks; phy_block++) {
+               if (!get_bb(phy_block, apanic_bbt))
+                       good_block++;
+               if (good_block == (logic_block + 1))
+                       break;
+       }
+
+       if (good_block != (logic_block + 1))
+               return APANIC_INVALID_OFFSET;
+
+       return offset + ((phy_block-logic_block)<<mtd->erasesize_shift);
+}
+
 static void apanic_erase_callback(struct erase_info *done)
 {
        wait_queue_head_t *wait_q = (wait_queue_head_t *) done->priv;
@@ -117,10 +181,17 @@ static int apanic_proc_read(char *buffer, char **start, off_t offset,
        page_no = (file_offset + offset) / ctx->mtd->writesize;
        page_offset = (file_offset + offset) % ctx->mtd->writesize;
 
+
+       if (phy_offset(ctx->mtd, (page_no * ctx->mtd->writesize))
+               == APANIC_INVALID_OFFSET) {
+               pr_err("apanic: reading an invalid address\n");
+               mutex_unlock(&drv_mutex);
+               return -EINVAL;
+       }
        rc = ctx->mtd->read(ctx->mtd,
-                           (page_no * ctx->mtd->writesize),
-                           ctx->mtd->writesize,
-                           &len, ctx->bounce);
+               phy_offset(ctx->mtd, (page_no * ctx->mtd->writesize)),
+               ctx->mtd->writesize,
+               &len, ctx->bounce);
 
        if (page_offset)
                count -= page_offset;
@@ -153,14 +224,7 @@ static void mtd_panic_erase(void)
                set_current_state(TASK_INTERRUPTIBLE);
                add_wait_queue(&wait_q, &wait);
 
-               rc = ctx->mtd->block_isbad(ctx->mtd, erase.addr);
-               if (rc < 0) {
-                       printk(KERN_ERR
-                              "apanic: Bad block check "
-                              "failed (%d)\n", rc);
-                       goto out;
-               }
-               if (rc) {
+               if (get_bb(erase.addr>>ctx->mtd->erasesize_shift, apanic_bbt)) {
                        printk(KERN_WARNING
                               "apanic: Skipping erase of bad "
                               "block @%llx\n", erase.addr);
@@ -187,6 +251,8 @@ static void mtd_panic_erase(void)
                                printk(KERN_INFO
                                       "apanic: Marked a bad block"
                                       " @%llx\n", erase.addr);
+                               set_bb(erase.addr>>ctx->mtd->erasesize_shift,
+                                       apanic_bbt);
                                continue;
                        }
                        goto out;
@@ -237,12 +303,16 @@ static void mtd_panic_notify_add(struct mtd_info *mtd)
 
        ctx->mtd = mtd;
 
-       if (mtd->block_isbad(mtd, 0)) {
-               printk(KERN_ERR "apanic: Offset 0 bad block. Boourns!\n");
+       alloc_bbt(mtd, apanic_bbt);
+       scan_bbt(mtd, apanic_bbt);
+
+       if (apanic_good_blocks == 0) {
+               printk(KERN_ERR "apanic: no any good blocks?!\n");
                goto out_err;
        }
 
-       rc = mtd->read(mtd, 0, mtd->writesize, &len, ctx->bounce);
+       rc = mtd->read(mtd, phy_offset(mtd, 0), mtd->writesize,
+                       &len, ctx->bounce);
        if (rc && rc == -EBADMSG) {
                printk(KERN_WARNING
                       "apanic: Bad ECC on block 0 (ignored)\n");
@@ -341,6 +411,12 @@ static int apanic_writeflashpage(struct mtd_info *mtd, loff_t to,
                return 0;
        }
 
+       to = phy_offset(mtd, to);
+       if (to == APANIC_INVALID_OFFSET) {
+               printk(KERN_EMERG "apanic: write to invalid address\n");
+               return 0;
+       }
+
        if (panic)
                rc = mtd->panic_write(mtd, to, mtd->writesize, &wlen, buf);
        else
@@ -386,34 +462,12 @@ static int apanic_write_console(struct mtd_info *mtd, unsigned int off)
                        break;
                if (rc != mtd->writesize)
                        memset(ctx->bounce + rc, 0, mtd->writesize - rc);
-#if CHECK_BB
-check_badblock:
-               rc = mtd->block_isbad(mtd, off);
-               if (rc < 0) {
-                       printk(KERN_ERR
-                              "apanic: Bad block check "
-                              "failed (%d)\n", rc);
-               }
-               if (rc) {
-                       printk(KERN_WARNING
-                              "apanic: Skipping over bad "
-                              "block @%x\n", off);
-                       off += mtd->erasesize;
-                       printk("chk %u %llu\n", off, mtd->size);
-                       if (off >= mtd->size) {
-                               printk(KERN_EMERG
-                                      "apanic: Too many bad blocks!\n");
-                                      return -EIO;
-                       }
-                       goto check_badblock;
-               }
-#endif
 
                rc2 = apanic_writeflashpage(mtd, off, ctx->bounce);
                if (rc2 <= 0) {
                        printk(KERN_EMERG
                               "apanic: Flash write failed (%d)\n", rc2);
-                       return rc2;
+                       return idx;
                }
                if (!last_chunk)
                        idx += rc2;
@@ -442,6 +496,7 @@ static int apanic(struct notifier_block *this, unsigned long event,
        /* Ensure that cond_resched() won't try to preempt anybody */
        add_preempt_count(PREEMPT_ACTIVE);
 #endif
+       touch_softlockup_watchdog();
 
        if (!ctx->mtd)
                goto out;