Adds initial documentation for the gpt command
Signed-off-by: Joshua Watt JPEWhacker@gmail.com --- doc/usage/cmd/gpt.rst | 139 ++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 139 insertions(+) create mode 100644 doc/usage/cmd/gpt.rst
diff --git a/doc/usage/cmd/gpt.rst b/doc/usage/cmd/gpt.rst new file mode 100644 index 0000000000..ea2cf73a60 --- /dev/null +++ b/doc/usage/cmd/gpt.rst @@ -0,0 +1,139 @@ +.. SPDX-License-Identifier: GPL-2.0+ + +gpt command +=========== + +Synopsis +-------- + +:: + + gpt repair <interface> <device no> + gpt write <interface> <device no> <partition string> + gpt verify <interface> <device no> <partition string> + gpt setenv <interface> <device no> <partition name> + gpt enumerate <interface> <device no> + gpt guid <interface> <device no> [<varname>] + gpt read <interface> <device no> [<varname>] + gpt swap <interface> <dev> <name1> <name2> + gpt rename <interface> <dev> <part> <name> + +Description +----------- + +The gpt command lets users read, create, modify, or verify the GPT (GUID +Partition Table) partition layout. + +The syntax of the text description of the partition list is similar to +the one used by the 'mbr' command. + +The partition list may start with a set of parameters for the whole disk: + +* uuid_disk (the UUID of the disk) + +Following the disk parameters, partitions are specified separated by a ';'. +Supported partition parameters are: + +* name (required) +* start (required, partition start offset in bytes) +* size (in bytes or '-' to expand it to the whole free area) +* bootable (boolean flag) +* uuid (partition UUID, optional if CONFIG_RANDOM_UUID=y is enabled) +* type (partition type GUID, requires CONFIG_PARTITION_TYPE_GUID=y) + +Here is an example how to create a 6 partitions, some of the predefined sizes: + +:: + + => setenv gpt_parts 'uuid_disk=bec9fc2a-86c1-483d-8a0e-0109732277d7; + name=boot,start=4M,size=128M,bootable,type=EBD0A0A2-B9E5-4433-87C0-68B6B72699C7, + name=rootfs,size=3072M,type=0FC63DAF-8483-4772-8E79-3D69D8477DE4; + name=system-data,size=512M,type=0FC63DAF-8483-4772-8E79-3D69D8477DE4; + name=[ext],size=-,type=0FC63DAF-8483-4772-8E79-3D69D8477DE4; + name=user,size=-,type=0FC63DAF-8483-4772-8E79-3D69D8477DE4; + name=modules,size=100M,type=0FC63DAF-8483-4772-8E79-3D69D8477DE4; + name=ramdisk,size=8M,type=0FC63DAF-8483-4772-8E79-3D69D8477DE4 + => gpt write mmc 0 $gpt_parts + + +If 'uuid' is not specified, but CONFIG_RANDOM_UUID is enabled, a random UUID +will be generated for the partition + +The 'gpt verify' command returns 0 if the layout matches the one on the storage +device or 1 if not. To check if the layout on the MMC #0 storage device +matches the provided text description one has to issue following command: + +:: + + => gpt verify mmc 0 $gpt_parts + +The verify sub-command is especially useful in the system update scripts: + +:: + + => if gpt verify mmc 0 $gpt_parts; then + echo GPT layout needs to be updated + ... + fi + +The 'gpt write' command returns 0 on success write or 1 on failure. + +The 'gpt setenv' command will set a series of environment variables with +information about a particular partition. The variables are: + +* gpt_partition_addr (the starting offset of the partition, in hexadecimal blocks) +* gpt_partition_size (the size of the partition, in hexadecimal blocks) +* gpt_partition_name (the name of the partition) +* gpt_partition_entry (the partition number in the table, e.g. 1, 2, 3, etc.) + +To get the information about the partition named 'rootfs', issue the following +command: + +:: + => gpt setenv mmc 0 rootfs + => echo ${gpt_partition_addr} + 2000 + => echo ${gpt_partition_size} + 14a000 + => echo ${gpt_partition_name} + rootfs + => echo ${gpt_partition_entry} + 2 + +The 'gpt enumerate' command will set the variable 'gpt_partition_list' with the +list of partition names on the device. For example: + +:: + => gpt enumerate + => echo gpt_partition_list + boot rootfs system-data [ext] user modules ramdisk + +The 'gpt guid' command will report the GUID of a disk. If 'varname' is +specified, the command will set the variable to the GUID, otherwise it will be +printed out. For example: + +:: + => gpt guid mmc 0 + bec9fc2a-86c1-483d-8a0e-0109732277d7 + => gpt guid mmc gpt_disk_uuid + => echo ${gpt_disk_uuid} + bec9fc2a-86c1-483d-8a0e-0109732277d7 + +The 'gpt read' command will print out the current state of the GPT partition +table. If 'varname' is specified, the variable will be filled with a partition +string as described above that is suitable for passing to other 'gpt' commands. +If omitted, a human readable description is printed out. +CONFIG_CMD_GPT_RENAME=y is required. + +The 'gpt swap' command changes the names of all partitions that are named +'name1' to be 'name2', and all partitions named 'name2' to be 'name1'. +CONFIG_CMD_GPT_RENAME=y is required. + +The 'gpt rename' command renames all partitions named 'part' to be 'name1'. +CONFIG_CMD_GPT_RENAME=y is required. + +Configuration +------------- + +To use the 'gpt' command you must specify CONFIG_CMD_GPT=y. To enable 'gpt +read', 'gpt swap' and 'gpt rename', you must specify CONFIG_CMD_GPT_RENAME=y.