cmd_part: add partition-related command

This implements the following:

part uuid mmc 0:1
  -> print partition UUID
part uuid mmc 0:1 uuid
  -> set environment variable to partition UUID
part list mmc 0
  -> list the partitions on the specified device

"part uuid" 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} ...

Signed-off-by: Stephen Warren <swarren@nvidia.com>

common/Makefile

@@ -136,6 +136,7 @@ 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

common/cmd_part.c

@@ -0,0 +1,105 @@
+/*
+ * 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@esd-electronics.com>
+ *
+ * made from cmd_reiserfs by
+ *
+ * (C) Copyright 2003 - 2004
+ * Sysgo Real-Time Solutions, AG <www.elinos.com>
+ * Pavel Bartusek <pba@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_part_uuid(int argc, char * const argv[])
+{
+	int part;
+	block_dev_desc_t *dev_desc;
+	disk_partition_t info;
+
+	if (argc < 2)
+		return CMD_RET_USAGE;
+	if (argc > 3)
+		return CMD_RET_USAGE;
+
+	part = get_device_and_partition(argv[0], argv[1], &dev_desc, &info, 0);
+	if (part < 0)
+		return 1;
+
+	if (argc > 2)
+		setenv(argv[2], info.uuid);
+	else
+		printf("%s\n", info.uuid);
+
+	return 0;
+}
+
+int do_part_list(int argc, char * const argv[])
+{
+	int ret;
+	block_dev_desc_t *desc;
+
+	if (argc != 2)
+		return CMD_RET_USAGE;
+
+	ret = get_device(argv[0], argv[1], &desc);
+	if (ret < 0)
+		return 1;
+
+	print_part(desc);
+
+	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_part_uuid(argc - 2, argv + 2);
+	else if (!strcmp(argv[1], "list"))
+		return do_part_list(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\n"
+	"part list <interface> <dev>\n"
+	"    - print a device's partition table"
+);