linux-kernel - [PATCH]MTD:Fix ctrl-alt-del cann't reboot for intel flash bug

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Date:	Thu, 26 Jul 2007 11:38:13 +0800
From:	"Kevin Hao" <haokexin@...il.com>
To:	linux-kernel <linux-kernel@...r.kernel.org>
Cc:	dwmw2@...radead.org
Subject: [PATCH]MTD:Fix ctrl-alt-del cann't reboot for intel flash bug

hi,

  When we press ctrl-alt-del,kernel_restart_prepare will revoke
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 sheduled to
running and programming flash in not FL_READY mode again.So we cann't
boot up if this flash is used
for bootloader.This patch is against current Linus git tree.
   Sorry,my english is a little rusty.:-)
   Appreciated for any comment.

diff --git a/drivers/mtd/chips/cfi_cmdset_0001.c
b/drivers/mtd/chips/cfi_cmdset_0001.c
index 2f19fa7..a1009df 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);
@@ -2402,10 +2405,10 @@ 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 a293a3b..39e7d2a 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;
-
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