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diff --git a/doc/usage/cmd/read.rst b/doc/usage/cmd/read.rst new file mode 100644 index 0000000000..840846728f --- /dev/null +++ b/doc/usage/cmd/read.rst @@ -0,0 +1,44 @@ +.. SPDX-License-Identifier: GPL-2.0-or-later: + +read and write commands +======================= + +Synopsis +-------- + +:: + + read <interface> <dev[:part|#partname]> <addr> <blk#> <cnt> + write <interface> <dev[:part|#partname]> <addr> <blk#> <cnt> + +The read and write commands can be used for raw access to data in +block devices (or partitions therein), i.e. without going through a +file system. + +read +---- + +The block device is specified using the <interface> (e.g. "mmc") and +<dev> parameters. If the block device has a partition table, one can +optionally specify a partition number (using the :part syntax) or +partition name (using the #partname syntax). The command then reads +the <cnt> blocks of data starting at block number <blk#> of the given +device/partition to the memory address <addr>. + +write +----- + +The write command is completely equivalent to the read command, except +of course that the transfer direction is reversed. + +Examples +-------- + + # Read 2 MiB from partition 3 of mmc device 2 to $loadaddr + read mmc 2.3 $loadaddr 0 0x1000 + + # Read 16 MiB from the partition named 'kernel' of mmc device 1 to $loadaddr + read mmc 1#kernel $loadaddr 0 0x8000 + + # Write to the third sector of the partition named 'bootdata' of mmc device 0 + write mmc 0#bootdata $loadaddr 2 1 |