X-Git-Url: https://git.librecmc.org/?a=blobdiff_plain;f=doc%2FREADME.gpt;h=62013a3f89e2ed753915e82f969f98db19df516f;hb=6c69ed19f96203680ba752fdeb22d58df4715815;hp=c0acc8ade5c72afdc0e0ec6936be8b94b093ff69;hpb=564cf25d5b1b90ae790e2b7619292935f40b13e6;p=oweals%2Fu-boot.git

diff --git a/doc/README.gpt b/doc/README.gpt
index c0acc8ade5..62013a3f89 100644
--- a/doc/README.gpt
+++ b/doc/README.gpt
@@ -1,10 +1,8 @@
+# SPDX-License-Identifier: GPL-2.0+
 #
 #  Copyright (C) 2012 Samsung Electronics
 #
 #  Lukasz Majewski <l.majewski@samsung.com>
-#
-#
-# SPDX-License-Identifier:	GPL-2.0+
 
 Glossary:
 ========
@@ -156,10 +154,10 @@ Creating GPT partitions in U-Boot:
 To restore GUID partition table one needs to:
 1. Define partition layout in the environment.
    Format of partitions layout:
-     "partitions=uuid_disk=...;name=u-boot,size=60MiB,uuid=...;
+     "uuid_disk=...;name=u-boot,size=60MiB,uuid=...;
 	name=kernel,size=60MiB,uuid=...;"
      or
-     "partitions=uuid_disk=${uuid_gpt_disk};name=${uboot_name},
+     "uuid_disk=${uuid_gpt_disk};name=${uboot_name},
 	size=${uboot_size},uuid=${uboot_uuid};"
 
    The fields 'name' and 'size' are mandatory for every partition.
@@ -171,7 +169,8 @@ To restore GUID partition table one needs to:
    The fields 'uuid' and 'uuid_disk' are optional if CONFIG_RANDOM_UUID is
    enabled. A random uuid will be used if omitted or they point to an empty/
    non-existent environment variable. The environment variable will be set to
-   the generated UUID.
+   the generated UUID.  The 'gpt guid' command reads the current value of the
+   uuid_disk from the GPT.
 
    The field 'bootable' is optional, it is used to mark the GPT partition
    bootable (set attribute flags "Legacy BIOS bootable").
@@ -209,6 +208,24 @@ Following line can be used to assess if GPT verification has succeed:
 U-BOOT> gpt verify mmc 0 $partitions
 U-BOOT> if test $? = 0; then echo "GPT OK"; else echo "GPT ERR"; fi
 
+Renaming GPT partitions from U-Boot:
+====================================
+
+GPT partition names are a mechanism via which userspace and U-Boot can
+communicate about software updates and boot failure.  The 'gpt guid',
+'gpt read', 'gpt rename' and 'gpt swap' commands facilitate
+programmatic renaming of partitions from bootscripts by generating and
+modifying the partitions layout string.  Here is an illustration of
+employing 'swap' to exchange 'primary' and 'backup' partition names:
+
+U-BOOT> gpt swap mmc 0 primary backup
+
+Afterwards, all partitions previously named 'primary' will be named
+'backup', and vice-versa.  Alternatively, single partitions may be
+renamed.  In this example, mmc0's first partition will be renamed
+'primary':
+
+U-BOOT> gpt rename mmc 0 1 primary
 
 The GPT functionality may be tested with the 'sandbox' board by
 creating a disk image as described under 'Block Device Emulation' in
@@ -217,7 +234,7 @@ board/sandbox/README.sandbox:
 =>host bind 0 ./disk.raw
 => gpt read host 0
 [ . . . ]
-=> gpt flip host 0
+=> gpt swap host 0 name othername
 [ . . . ]
 
 Partition type GUID:
@@ -229,7 +246,7 @@ PARTITION_BASIC_DATA_GUID (EBD0A0A2-B9E5-4433-87C0-68B6B72699C7).
 If you define 'CONFIG_PARTITION_TYPE_GUID', a optionnal parameter 'type'
 can specify a other partition type guid:
 
-     "partitions=uuid_disk=...;name=u-boot,size=60MiB,uuid=...;
+     "uuid_disk=...;name=u-boot,size=60MiB,uuid=...;
 	name=kernel,size=60MiB,uuid=...,
 	type=0FC63DAF-8483-4772-8E79-3D69D8477DE4;"
 
@@ -251,7 +268,7 @@ Some strings can be also used at the place of known GUID :
 	"lvm"    = PARTITION_LINUX_LVM_GUID
 	           (E6D6D379-F507-44C2-A23C-238F2A3DF928)
 
-    "partitions=uuid_disk=...;name=u-boot,size=60MiB,uuid=...;
+    "uuid_disk=...;name=u-boot,size=60MiB,uuid=...;
 	name=kernel,size=60MiB,uuid=...,type=linux;"
 
 They are also used to display the type of partition in "part list" command.