[MTD] CFI-0002 - Improve error checking

Check for errors besides infinite loops when writing and erasing.

Signed-off-by: Eric W. Biederman <ebiederman@lnxi.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

1 files changed, 67 insertions, 32 deletions

diff --git a/drivers/mtd/chips/cfi_cmdset_0002.c b/drivers/mtd/chips/cfi_cmdset_0002.c
index fca8ff6f7e14..59849236f526 100644
--- a/drivers/mtd/chips/cfi_cmdset_0002.c
+++ b/drivers/mtd/chips/cfi_cmdset_0002.c
@@ -13,7 +13,7 @@
  *
  * This code is GPL
  *
- * $Id: cfi_cmdset_0002.c,v 1.114 2004/12/11 15:43:53 dedekind Exp $
+ * $Id: cfi_cmdset_0002.c,v 1.115 2005/05/20 03:28:23 eric Exp $
  *
  */
 
@@ -43,6 +43,7 @@
 #define MANUFACTURER_AMD        0x0001
 #define MANUFACTURER_SST        0x00BF
 #define SST49LF004B             0x0060
+#define SST49LF008A             0x005a
 
 static int cfi_amdstd_read (struct mtd_info *, loff_t, size_t, size_t *, u_char *);
 static int cfi_amdstd_write_words(struct mtd_info *, loff_t, size_t, size_t *, const u_char *);
@@ -191,6 +192,7 @@ static struct cfi_fixup cfi_fixup_table[] = {
 };
 static struct cfi_fixup jedec_fixup_table[] = {
         { MANUFACTURER_SST, SST49LF004B, fixup_use_fwh_lock, NULL, },
+        { MANUFACTURER_SST, SST49LF008A, fixup_use_fwh_lock, NULL, },
         { 0, 0, NULL, NULL }
 };
 
@@ -401,6 +403,32 @@ static int chip_ready(struct map_info *map, unsigned long addr)
         return map_word_equal(map, d, t);
 }
 
+/*
+ * Return true if the chip is ready and has the correct value.
+ *
+ * Ready is one of: read mode, query mode, erase-suspend-read mode (in any
+ * non-suspended sector) and it is indicated by no bits toggling.
+ *
+ * Error are indicated by toggling bits or bits held with the wrong value,
+ * or with bits toggling.
+ *
+ * Note that anything more complicated than checking if no bits are toggling
+ * (including checking DQ5 for an error status) is tricky to get working
+ * correctly and is therefore not done  (particulary with interleaved chips
+ * as each chip must be checked independantly of the others).
+ *
+ */
+static int chip_good(struct map_info *map, unsigned long addr, map_word expected)
+{
+        map_word oldd, curd;
+
+        oldd = map_read(map, addr);
+        curd = map_read(map, addr);
+
+        return  map_word_equal(map, oldd, curd) && 
+                map_word_equal(map, curd, expected);
+}
+
 static int get_chip(struct map_info *map, struct flchip *chip, unsigned long adr, int mode)
 {
         DECLARE_WAITQUEUE(wait, current);
@@ -765,26 +793,29 @@ static int do_write_oneword(struct map_info *map, struct flchip *chip, unsigned
                 }
 
                 if (chip_ready(map, adr))
-                        goto op_done;
+                        break;
 
-                if (time_after(jiffies, timeo))
+                if (time_after(jiffies, timeo)) {
+                        printk(KERN_WARNING "MTD %s(): software timeout\n", __func__);
                         break;
+                }
 
                 /* Latency issues. Drop the lock, wait a while and retry */
                 cfi_spin_unlock(chip->mutex);
                 cfi_udelay(1);
                 cfi_spin_lock(chip->mutex);
         }
+        /* Did we succeed? */
+        if (!chip_good(map, adr, datum)) {
+                /* reset on all failures. */
+                map_write( map, CMD(0xF0), chip->start );
+                /* FIXME - should have reset delay before continuing */
 
-        printk(KERN_WARNING "MTD %s(): software timeout\n", __func__);
-
-        /* reset on all failures. */
-        map_write( map, CMD(0xF0), chip->start );
-        /* FIXME - should have reset delay before continuing */
-        if (++retry_cnt <= MAX_WORD_RETRIES) 
-                goto retry;
+                if (++retry_cnt <= MAX_WORD_RETRIES) 
+                        goto retry;
 
-        ret = -EIO;
+                ret = -EIO;
+        }
  op_done:
         chip->state = FL_READY;
         put_chip(map, chip, adr);
@@ -1187,10 +1218,13 @@ static inline int do_erase_chip(struct map_info *map, struct flchip *chip)
                 }
 
                 if (chip_ready(map, adr))
-                        goto op_done;
+                        break;
 
-                if (time_after(jiffies, timeo))
+                if (time_after(jiffies, timeo)) {
+                        printk(KERN_WARNING "MTD %s(): software timeout\n",
+                                __func__ );
                         break;
+                }
 
                 /* Latency issues. Drop the lock, wait a while and retry */
                 cfi_spin_unlock(chip->mutex);
@@ -1198,16 +1232,15 @@ static inline int do_erase_chip(struct map_info *map, struct flchip *chip)
                 schedule_timeout(1);
                 cfi_spin_lock(chip->mutex);
         }
+        /* Did we succeed? */
+        if (!chip_good(map, adr, map_word_ff(map))) {
+                /* reset on all failures. */
+                map_write( map, CMD(0xF0), chip->start );
+                /* FIXME - should have reset delay before continuing */
 
-        printk(KERN_WARNING "MTD %s(): software timeout\n",
-               __func__ );
-
-        /* reset on all failures. */
-        map_write( map, CMD(0xF0), chip->start );
-        /* FIXME - should have reset delay before continuing */
+                ret = -EIO;
+        }
 
-        ret = -EIO;
- op_done:
         chip->state = FL_READY;
         put_chip(map, chip, adr);
         cfi_spin_unlock(chip->mutex);
@@ -1272,10 +1305,13 @@ static inline int do_erase_oneblock(struct map_info *map, struct flchip *chip, u
                 }
 
                 if (chip_ready(map, adr))
-                        goto op_done;
+                        break;
 
-                if (time_after(jiffies, timeo))
+                if (time_after(jiffies, timeo)) {
+                        printk(KERN_WARNING "MTD %s(): software timeout\n",
+                                __func__ );
                         break;
+                }
 
                 /* Latency issues. Drop the lock, wait a while and retry */
                 cfi_spin_unlock(chip->mutex);
@@ -1283,16 +1319,15 @@ static inline int do_erase_oneblock(struct map_info *map, struct flchip *chip, u
                 schedule_timeout(1);
                 cfi_spin_lock(chip->mutex);
         }
-        
-        printk(KERN_WARNING "MTD %s(): software timeout\n",
-               __func__ );
-        
-        /* reset on all failures. */
-        map_write( map, CMD(0xF0), chip->start );
-        /* FIXME - should have reset delay before continuing */
+        /* Did we succeed? */
+        if (chip_good(map, adr, map_word_ff(map))) {
+                /* reset on all failures. */
+                map_write( map, CMD(0xF0), chip->start );
+                /* FIXME - should have reset delay before continuing */
+
+                ret = -EIO;
+        }
 
-        ret = -EIO;
- op_done:
         chip->state = FL_READY;
         put_chip(map, chip, adr);
         cfi_spin_unlock(chip->mutex);