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Allows device MMC boot partitions to be accessed. MMC partitions are treated effectively as separate block devices on the same MMC card. Signed-off-by: Andrei Warkentin <[email protected]> Acked-by: Arnd Bergmann <[email protected]> Signed-off-by: Chris Ball <[email protected]>
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SD and MMC Device Partitions | ||
============================ | ||
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Device partitions are additional logical block devices present on the | ||
SD/MMC device. | ||
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As of this writing, MMC boot partitions as supported and exposed as | ||
/dev/mmcblkXboot0 and /dev/mmcblkXboot1, where X is the index of the | ||
parent /dev/mmcblkX. | ||
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MMC Boot Partitions | ||
=================== | ||
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Read and write access is provided to the two MMC boot partitions. Due to | ||
the sensitive nature of the boot partition contents, which often store | ||
a bootloader or bootloader configuration tables crucial to booting the | ||
platform, write access is disabled by default to reduce the chance of | ||
accidental bricking. | ||
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To enable write access to /dev/mmcblkXbootY, disable the forced read-only | ||
access with: | ||
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echo 0 > /sys/block/mmcblkXbootY/force_ro | ||
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To re-enable read-only access: | ||
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echo 1 > /sys/block/mmcblkXbootY/force_ro |
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