env: Fix env_load_location

[people/ms/u-boot.git] / doc / README.gpt

diff --git a/doc/README.gpt b/doc/README.gpt
index 543bf872d073190ef1c2773fea12003b8267c053..d3db8bce1ca3114b3d7be8a1e101e3d3b9069d3f 100644 (file)
--- a/doc/README.gpt
+++ b/doc/README.gpt
@@ -171,7 +171,8 @@ 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").
@@ -209,16 +210,24 @@ 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:
+====================================
 
-The GPT functionality may be tested with the 'sandbox' board by
-creating a disk image as described under 'Block Device Emulation' in
-board/sandbox/README.sandbox:
+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:
 
-=>host bind 0 ./disk.raw
-=> gpt read host 0
-[ . . . ]
-=> gpt flip host 0
-[ . . . ]
+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
@@ -227,7 +236,7 @@ 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: