cmd:gpt: randomly generate each partition uuid if undefined

Changes:
- randomly generate partition uuid if any is undefined and CONFIG_RAND_UUID
  is defined
- print debug info about set/unset/generated uuid
- update doc/README.gpt

Signed-off-by: Przemyslaw Marczak <p.marczak@samsung.com>
Acked-by: Lukasz Majewski <l.majewski@samsung.com>
Cc: Piotr Wilczek <p.wilczek@samsung.com>
Cc: Tom Rini <trini@ti.com>
Cc: Stephen Warren <swarren@nvidia.com>
Cc: Lukasz Majewski <l.majewski@samsung.com>

1 files changed, 17 insertions, 5 deletions

diff --git a/doc/README.gpt b/doc/README.gpt
index 5c133f3..f822894 100644
--- a/doc/README.gpt
+++ b/doc/README.gpt
@@ -132,8 +132,8 @@ of the Primary.
 	   ----------------------
 	   Offset  Size    Description
 
-	   0       16 B    Partition type GUID
-	   16      16 B    Unique partition GUID
+	   0       16 B    Partition type GUID (Big Endian)
+	   16      16 B    Unique partition GUID in (Big Endian)
 	   32      8  B    First LBA (Little Endian)
 	   40      8  B    Last LBA (inclusive)
 	   48      8  B    Attribute flags [+]
@@ -160,6 +160,9 @@ To restore GUID partition table one needs to:
    Fields 'name', 'size' and 'uuid' are mandatory for every partition.
    The field 'start' is optional.
 
+   option: CONFIG_RANDOM_UUID
+   If any partition "UUID" no exists then it is randomly generated.
+
 2. Define 'CONFIG_EFI_PARTITION' and 'CONFIG_CMD_GPT'
 
 2. From u-boot prompt type:
@@ -168,11 +171,20 @@ To restore GUID partition table one needs to:
 Useful info:
 ============
 
-Two programs, namely: 'fdisk' and 'parted' are recommended to work with GPT
-recovery. Parted is able to handle GUID partitions. Unfortunately the 'fdisk'
-hasn't got such ability.
+Two programs, namely: 'gdisk' and 'parted' are recommended to work with GPT
+recovery. Both are able to handle GUID partitions.
 Please, pay attention at -l switch for parted.
 
 "uuid" program is recommended to generate UUID string. Moreover it can decode
 (-d switch) passed in UUID string. It can be used to generate partitions UUID
 passed to u-boot environment variables.
+If optional CONFIG_RANDOM_UUID is defined then for any partition which environment
+uuid is unset, uuid is randomly generated and stored in correspond environment
+variable.
+
+note:
+Each string block of UUID generated by program "uuid" is in big endian and it is
+also stored in big endian in disk GPT.
+Partitions layout can be printed by typing "mmc part". Note that each partition
+GUID has different byte order than UUID generated before, this is because first
+three blocks of GUID string are in Little Endian.