mtd: fix hang-up in cfi erase and read contention

cfi erase command hangs up when erase and read contention occurs.
If read runs at the same address as erase operation, read issues
Erase-Suspend via get_chip() and the erase goes into sleep in wait queue.
But in this case, read operation exits by time-out without waking it up.

I think the other variants (0001, 0020 and lpddr) have the same problem too.
Tested and verified the patch only on CFI-0002 flash, though.

Signed-off-by: Tadashi Abe <tabe@mvista.com>
Acked-by: Joakim Tjernlund <joakim.tjernlund@transmode.se>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

drivers/mtd/chips/cfi_cmdset_0001.c

@@ -812,12 +812,9 @@ static int chip_ready (struct map_info *map, struct flchip *chip, unsigned long
 			        break;
 
 			if (time_after(jiffies, timeo)) {
-				/* Urgh. Resume and pretend we weren't here.  */
-				map_write(map, CMD(0xd0), adr);
-				/* Make sure we're in 'read status' mode if it had finished */
-				map_write(map, CMD(0x70), adr);
-				chip->state = FL_ERASING;
-				chip->oldstate = FL_READY;
+				/* Urgh. Resume and pretend we weren't here.
+				 * Make sure we're in 'read status' mode if it had finished */
+				put_chip(map, chip, adr);
 				printk(KERN_ERR "%s: Chip not ready after erase "
 				       "suspended: status = 0x%lx\n", map->name, status.x[0]);
 				return -EIO;

drivers/mtd/chips/cfi_cmdset_0002.c

@@ -711,9 +711,7 @@ static int get_chip(struct map_info *map, struct flchip *chip, unsigned long adr
 				 * there was an error (so leave the erase
 				 * routine to recover from it) or we trying to
 				 * use the erase-in-progress sector. */
-				map_write(map, cfi->sector_erase_cmd, chip->in_progress_block_addr);
-				chip->state = FL_ERASING;
-				chip->oldstate = FL_READY;
+				put_chip(map, chip, adr);
 				printk(KERN_ERR "MTD %s(): chip not ready after erase suspend\n", __func__);
 				return -EIO;
 			}

drivers/mtd/chips/cfi_cmdset_0020.c

@@ -296,6 +296,7 @@ static inline int do_read_onechip(struct map_info *map, struct flchip *chip, lof
 				/* make sure we're in 'read status' mode */
 				map_write(map, CMD(0x70), cmd_addr);
 				chip->state = FL_ERASING;
+				wake_up(&chip->wq);
 				mutex_unlock(&chip->mutex);
 				printk(KERN_ERR "Chip not ready after erase "
 				       "suspended: status = 0x%lx\n", status.x[0]);

drivers/mtd/lpddr/lpddr_cmds.c

@@ -313,12 +313,7 @@ static int chip_ready(struct map_info *map, struct flchip *chip, int mode)
 		if (ret) {
 			/* Oops. something got wrong. */
 			/* Resume and pretend we weren't here.  */
-			map_write(map, CMD(LPDDR_RESUME),
-				map->pfow_base + PFOW_COMMAND_CODE);
-			map_write(map, CMD(LPDDR_START_EXECUTION),
-				map->pfow_base + PFOW_COMMAND_EXECUTE);
-			chip->state = FL_ERASING;
-			chip->oldstate = FL_READY;
+			put_chip(map, chip);
 			printk(KERN_ERR "%s: suspend operation failed."
 					"State may be wrong \n", map->name);
 			return -EIO;