[U-Boot] [PATCH 2/3] cmd_partuuid: add command to retrieve a partition's UUID

[Stephen Warren]

From: Stephen Warren <swarren at nvidia.com>

This implements the following:

partuuid mmc 0:1
  -> prints the partition's UUID.
partuuic mmc 0:1 uuid
  -> sets environment variable "uuid" to the partition's UUID.

This can be useful when writing a bootcmd which searches all known
devices for something bootable, and then wants the kernel to use the
same partition as the root device, e.g.:

partuuid ${devtype} ${devnum}:${rootpart} uuid
setenv bootargs root=PARTUUID=${uuid} ...

Signed-off-by: Stephen Warren <swarren at nvidia.com>
---
 common/Makefile       |    1 +
 common/cmd_partuuid.c |   87 +++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 88 insertions(+), 0 deletions(-)
 create mode 100644 common/cmd_partuuid.c

diff --git a/common/Makefile b/common/Makefile
index 483eb4d..bc39997 100644
--- a/common/Makefile
+++ b/common/Makefile
@@ -129,6 +129,7 @@ COBJS-$(CONFIG_CMD_NAND) += cmd_nand.o
 COBJS-$(CONFIG_CMD_NET) += cmd_net.o
 COBJS-$(CONFIG_CMD_ONENAND) += cmd_onenand.o
 COBJS-$(CONFIG_CMD_OTP) += cmd_otp.o
+COBJS-$(CONFIG_CMD_PARTUUID) += cmd_partuuid.o
 ifdef CONFIG_PCI
 COBJS-$(CONFIG_CMD_PCI) += cmd_pci.o
 endif
diff --git a/common/cmd_partuuid.c b/common/cmd_partuuid.c
new file mode 100644
index 0000000..c85606c
--- /dev/null
+++ b/common/cmd_partuuid.c
@@ -0,0 +1,87 @@
+/*
+ * Copyright (c) 2012, NVIDIA CORPORATION.  All rights reserved.
+ *
+ * made from cmd_ext2, which was:
+ *
+ * (C) Copyright 2004
+ * esd gmbh <www.esd-electronics.com>
+ * Reinhard Arlt <reinhard.arlt at esd-electronics.com>
+ *
+ * made from cmd_reiserfs by
+ *
+ * (C) Copyright 2003 - 2004
+ * Sysgo Real-Time Solutions, AG <www.elinos.com>
+ * Pavel Bartusek <pba at sysgo.com>
+ *
+ * See file CREDITS for list of people who contributed to this
+ * project.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of
+ * the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <common.h>
+#include <config.h>
+#include <command.h>
+#include <part.h>
+#include <vsprintf.h>
+
+int do_partuuid(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
+{
+	int dev;
+	int part;
+	char *ep;
+	block_dev_desc_t *dev_desc;
+	disk_partition_t info;
+
+	if (argc < 3)
+		return CMD_RET_USAGE;
+
+	dev = (int)simple_strtoul(argv[2], &ep, 16);
+	dev_desc = get_dev(argv[1], dev);
+	if (dev_desc == NULL) {
+		printf("Block device %s %d not supported\n", argv[1], dev);
+		return 1;
+	}
+
+	if (*ep) {
+		if (*ep != ':') {
+			puts("Invalid device; use dev[:part]\n");
+			return 1;
+		}
+		part = (int)simple_strtoul(++ep, NULL, 16);
+	} else {
+		part = 1;
+	}
+
+	if (get_partition_info(dev_desc, part, &info)) {
+		printf("Bad partition %d\n", part);
+		return 1;
+	}
+
+	if (argc > 3)
+		setenv(argv[3], info.uuid);
+	else
+		printf("%s\n", info.uuid);
+
+	return 0;
+}
+
+U_BOOT_CMD(
+	partuuid,	4,	1,	do_partuuid,
+	"partition UUID retrieval",
+	"<interface> <dev[:part]>\n"
+	"    - show filesystem UUID of specified partition"
+	"<interface> <dev[:part]> <varname>\n"
+	"    - write filesystem UUID to environmane variable"
+);
-- 
1.7.0.4