[U-Boot] [PATCH V2 4/4] cmd_part: add partition-related command

[Stephen Warren]

From: Stephen Warren <swarren at nvidia.com>

This implements the following:

part uuid mmc 0:1
  -> print partition UUID
part uuid mmc 0:1 uuid
  -> set environment variable to partition 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.:

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

It is expected that further part sub-commands will be added later, e.g.
to find which partition on a disk is marked bootable, to write new
partition tables to disk, etc.

Signed-off-by: Stephen Warren <swarren at nvidia.com>
---
v2: validate that CONFIG_PARTITION_UUID is defined when CONFIG_CMD_PART is

Note: If Rob Herring's proposed patch "disk/part: introduce
get_device_and_partition" is applied, the body of do_partuuid() should
be reworked to use Rob's new function get_device_and_partition().
---
 common/Makefile   |    1 +
 common/cmd_part.c |  104 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 105 insertions(+), 0 deletions(-)
 create mode 100644 common/cmd_part.c

diff --git a/common/Makefile b/common/Makefile
index 3d62775..449b390 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-$(CONFIG_CMD_PART) += cmd_part.o
 ifdef CONFIG_PCI
 COBJS-$(CONFIG_CMD_PCI) += cmd_pci.o
 endif
diff --git a/common/cmd_part.c b/common/cmd_part.c
new file mode 100644
index 0000000..1b15ae9
--- /dev/null
+++ b/common/cmd_part.c
@@ -0,0 +1,104 @@
+/*
+ * 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>
+
+#ifndef CONFIG_PARTITION_UUIDS
+#error CONFIG_PARTITION_UUIDS must be enabled for CONFIG_CMD_PART to be enabled
+#endif
+
+int do_partuuid(int argc, char * const argv[])
+{
+	int dev;
+	int part;
+	char *ep;
+	block_dev_desc_t *dev_desc;
+	disk_partition_t info;
+
+	if (argc < 2)
+		return CMD_RET_USAGE;
+	if (argc > 3)
+		return CMD_RET_USAGE;
+
+	dev = (int)simple_strtoul(argv[1], &ep, 16);
+	dev_desc = get_dev(argv[0], dev);
+	if (dev_desc == NULL) {
+		printf("Block device %s %d not supported\n", argv[0], 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 > 2)
+		setenv(argv[2], info.uuid);
+	else
+		printf("%s\n", info.uuid);
+
+	return 0;
+}
+
+int do_part(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
+{
+	if (argc < 2)
+		return CMD_RET_USAGE;
+
+	if (!strcmp(argv[1], "uuid"))
+		return do_partuuid(argc - 2, argv + 2);
+
+	return CMD_RET_USAGE;
+}
+
+U_BOOT_CMD(
+	part,	5,	1,	do_part,
+	"disk partition related commands",
+	"part uuid <interface> <dev[:part]>\n"
+	"    - print partition UUID\n"
+	"part uuid <interface> <dev[:part]> <varname>\n"
+	"    - set environment variable to partition UUID"
+);
-- 
1.7.0.4