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

[Rob Herring]

On 09/05/2012 05:03 PM, Stephen Warren wrote:
> 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

What's the reason to not always both print out and set the uuid env var?

Perhaps the env name should be partuuid or part_uuid as you could have
uuid's for other purposes?

> 
> 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.

A list command would be useful and would be better located here than
under scsi or other interface commands. Perhaps instead of printing a
single part uuid, you should make a list command that prints all
partitions and their UUIDs. That would address my first question.

Rob

> 
> 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"
> +);
>