Merge branch 'fix/misc' into for-linus

[pandora-kernel.git] / drivers / mtd / ubi / build.c

diff --git a/drivers/mtd/ubi/build.c b/drivers/mtd/ubi/build.c
index 964a99d..e1f7d0a 100644 (file)
--- a/drivers/mtd/ubi/build.c
+++ b/drivers/mtd/ubi/build.c
@@ -41,6 +41,7 @@
 #include <linux/miscdevice.h>
 #include <linux/log2.h>
 #include <linux/kthread.h>
+#include <linux/reboot.h>
 #include "ubi.h"
 
 /* Maximum length of the 'mtd=' parameter */
@@ -656,6 +657,11 @@ static int io_init(struct ubi_device *ubi)
        if (ubi->mtd->block_isbad && ubi->mtd->block_markbad)
                ubi->bad_allowed = 1;
 
+       if (ubi->mtd->type == MTD_NORFLASH) {
+               ubi_assert(ubi->mtd->writesize == 1);
+               ubi->nor_flash = 1;
+       }
+
        ubi->min_io_size = ubi->mtd->writesize;
        ubi->hdrs_min_io_size = ubi->mtd->writesize >> ubi->mtd->subpage_sft;
 
@@ -822,6 +828,34 @@ static int autoresize(struct ubi_device *ubi, int vol_id)
        return 0;
 }
 
+/**
+ * ubi_reboot_notifier - halt UBI transactions immediately prior to a reboot.
+ * @n: reboot notifier object
+ * @state: SYS_RESTART, SYS_HALT, or SYS_POWER_OFF
+ * @cmd: pointer to command string for RESTART2
+ *
+ * This function stops the UBI background thread so that the flash device
+ * remains quiescent when Linux restarts the system. Any queued work will be
+ * discarded, but this function will block until do_work() finishes if an
+ * operation is already in progress.
+ *
+ * This function solves a real-life problem observed on NOR flashes when an
+ * PEB erase operation starts, then the system is rebooted before the erase is
+ * finishes, and the boot loader gets confused and dies. So we prefer to finish
+ * the ongoing operation before rebooting.
+ */
+static int ubi_reboot_notifier(struct notifier_block *n, unsigned long state,
+                              void *cmd)
+{
+       struct ubi_device *ubi;
+
+       ubi = container_of(n, struct ubi_device, reboot_notifier);
+       if (ubi->bgt_thread)
+               kthread_stop(ubi->bgt_thread);
+       ubi_sync(ubi->ubi_num);
+       return NOTIFY_DONE;
+}
+
 /**
  * ubi_attach_mtd_dev - attach an MTD device.
  * @mtd: MTD device description object
@@ -967,6 +1001,7 @@ int ubi_attach_mtd_dev(struct mtd_info *mtd, int ubi_num, int vid_hdr_offset)
        ubi_msg("number of PEBs reserved for bad PEB handling: %d",
                ubi->beb_rsvd_pebs);
        ubi_msg("max/mean erase counter: %d/%d", ubi->max_ec, ubi->mean_ec);
+       ubi_msg("image sequence number: %d", ubi->image_seq);
 
        /*
         * The below lock makes sure we do not race with 'ubi_thread()' which
@@ -978,6 +1013,11 @@ int ubi_attach_mtd_dev(struct mtd_info *mtd, int ubi_num, int vid_hdr_offset)
        wake_up_process(ubi->bgt_thread);
        spin_unlock(&ubi->wl_lock);
 
+       /* Flash device priority is 0 - UBI needs to shut down first */
+       ubi->reboot_notifier.priority = 1;
+       ubi->reboot_notifier.notifier_call = ubi_reboot_notifier;
+       register_reboot_notifier(&ubi->reboot_notifier);
+
        ubi_devices[ubi_num] = ubi;
        ubi_notify_all(ubi, UBI_VOLUME_ADDED, NULL);
        return ubi_num;
@@ -1049,6 +1089,7 @@ int ubi_detach_mtd_dev(int ubi_num, int anyway)
         * Before freeing anything, we have to stop the background thread to
         * prevent it from doing anything on this device while we are freeing.
         */
+       unregister_reboot_notifier(&ubi->reboot_notifier);
        if (ubi->bgt_thread)
                kthread_stop(ubi->bgt_thread);