[MTD] [NOR] fix ctrl-alt-del can't reboot for intel flash bug

When we press ctrl-alt-del,kernel_restart_prepare will invoke 
cfi_intelext_reboot which will set flash to read array mode, but later 
when device_shutdown is invoked which may put current work queue to 
sleep and other process may be scheduled to running and programming 
flash in not FL_READY mode again. So we can't boot up if this flash is 
used for bootloader.

Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: David Woodhouse <dwmw2@infradead.org>

2 files changed, 7 insertions, 3 deletions

diff --git a/drivers/mtd/chips/cfi_cmdset_0001.c b/drivers/mtd/chips/cfi_cmdset_0001.c
index c655e971c158..3aa3dca56ae6 100644
--- a/drivers/mtd/chips/cfi_cmdset_0001.c
+++ b/drivers/mtd/chips/cfi_cmdset_0001.c
@@ -653,7 +653,7 @@ static int get_chip(struct map_info *map, struct flchip *chip, unsigned long adr
  resettime:
         timeo = jiffies + HZ;
  retry:
-        if (chip->priv && (mode == FL_WRITING || mode == FL_ERASING || mode == FL_OTP_WRITE)) {
+        if (chip->priv && (mode == FL_WRITING || mode == FL_ERASING || mode == FL_OTP_WRITE || mode == FL_SHUTDOWN)) {
                 /*
                  * OK. We have possibility for contension on the write/erase
                  * operations which are global to the real chip and not per
@@ -798,6 +798,9 @@ static int get_chip(struct map_info *map, struct flchip *chip, unsigned long adr
                 if (mode == FL_READY && chip->oldstate == FL_READY)
                         return 0;
 
+        case FL_SHUTDOWN:
+                /* The machine is rebooting now,so no one can get chip anymore */
+                return -EIO;
         default:
         sleep:
                 set_current_state(TASK_UNINTERRUPTIBLE);
@@ -2409,10 +2412,10 @@ static int cfi_intelext_reset(struct mtd_info *mtd)
                    and switch to array mode so any bootloader in
                    flash is accessible for soft reboot. */
                 spin_lock(chip->mutex);
-                ret = get_chip(map, chip, chip->start, FL_SYNCING);
+                ret = get_chip(map, chip, chip->start, FL_SHUTDOWN);
                 if (!ret) {
                         map_write(map, CMD(0xff), chip->start);
-                        chip->state = FL_READY;
+                        chip->state = FL_SHUTDOWN;
                 }
                 spin_unlock(chip->mutex);
         }
diff --git a/include/linux/mtd/flashchip.h b/include/linux/mtd/flashchip.h
index a293a3b78e05..39e7d2a1be9a 100644
--- a/include/linux/mtd/flashchip.h
+++ b/include/linux/mtd/flashchip.h
@@ -40,6 +40,7 @@ typedef enum {
         FL_POINT,
         FL_XIP_WHILE_ERASING,
         FL_XIP_WHILE_WRITING,
+        FL_SHUTDOWN,
         FL_UNKNOWN
 } flstate_t;