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authorJohan Rudholm <johan.rudholm@stericsson.com>2011-12-02 08:51:06 +0100
committerChris Ball <cjb@laptop.org>2012-01-11 23:58:43 -0500
commitadd710eaa88606de8ba98a014d37178579e6dbaf (patch)
tree2d719508cabd213d5923cef95fdd3d6c9c40d977 /Documentation/mmc
parent92df954df3422a7dcf99eea34cf4cb68bb06ea08 (diff)
mmc: boot partition ro lock support
Enable boot partitions to be read-only locked until next power on via a sysfs entry. There will be one sysfs entry for each boot partition: /sys/block/mmcblkXbootY/ro_lock_until_next_power_on Each boot partition is locked by writing 1 to its file. Signed-off-by: Johan Rudholm <johan.rudholm@stericsson.com> Signed-off-by: John Beckett <john.beckett@stericsson.com> Signed-off-by: Chris Ball <cjb@laptop.org>
Diffstat (limited to 'Documentation/mmc')
-rw-r--r--Documentation/mmc/mmc-dev-parts.txt13
1 files changed, 13 insertions, 0 deletions
diff --git a/Documentation/mmc/mmc-dev-parts.txt b/Documentation/mmc/mmc-dev-parts.txt
index 2db28b8e662f..f08d078d43cf 100644
--- a/Documentation/mmc/mmc-dev-parts.txt
+++ b/Documentation/mmc/mmc-dev-parts.txt
@@ -25,3 +25,16 @@ echo 0 > /sys/block/mmcblkXbootY/force_ro
To re-enable read-only access:
echo 1 > /sys/block/mmcblkXbootY/force_ro
+
+The boot partitions can also be locked read only until the next power on,
+with:
+
+echo 1 > /sys/block/mmcblkXbootY/ro_lock_until_next_power_on
+
+This is a feature of the card and not of the kernel. If the card does
+not support boot partition locking, the file will not exist. If the
+feature has been disabled on the card, the file will be read-only.
+
+The boot partitions can also be locked permanently, but this feature is
+not accessible through sysfs in order to avoid accidental or malicious
+bricking.