[U-Boot] [PATCH 1/3] cmd: part: Allow passing partition name to start and size

[Lukasz Majewski <lukma@denx.de>]

On Mon, 26 Feb 2018 23:17:59 +0200
Sam Protsenko <semen.protsenko@linaro.org> wrote:

> Allow passing the partition name to "part start" and "part size"
> commands, so we can avoid magic numbers in the environment.
> 
> Consider one real use-case: in include/environment/ti/boot.h we have
> commands like these:
> 
>     setenv boot_part 9
>     part start mmc ${mmcdev} ${boot_part} boot_start
>     part size mmc ${mmcdev} ${boot_part} boot_size
>     mmc read ${loadaddr} ${boot_start} ${boot_size}
> 
> Now suppose that we have changed the partition table and boot_part now
> is 10. We will need to fix commands above. And anyone who relies on
> these boot commands, will need to change them accordingly, too (this
> was an actual case in our lab while testing Linux boot on Android
> environment).
> 
> By providing the option to pass partition name instead, we fix
> mentioned issue, by eliminating the necessity to use magic numbers.
> 
> Signed-off-by: Sam Protsenko <semen.protsenko@linaro.org>
> ---
>  cmd/part.c | 36 +++++++++++++++++++++++++-----------
>  1 file changed, 25 insertions(+), 11 deletions(-)
> 
> diff --git a/cmd/part.c b/cmd/part.c
> index 746bf40b2d..fd8825a7ec 100644
> --- a/cmd/part.c
> +++ b/cmd/part.c
> @@ -113,6 +113,7 @@ static int do_part_start(int argc, char * const
> argv[]) struct blk_desc *desc;
>  	disk_partition_t info;
>  	char buf[512] = { 0 };
> +	char *endp;
>  	int part;
>  	int err;
>  	int ret;
> @@ -122,15 +123,20 @@ static int do_part_start(int argc, char * const
> argv[]) if (argc > 4)
>  		return CMD_RET_USAGE;
>  
> -	part = simple_strtoul(argv[2], NULL, 0);
> -
>  	ret = blk_get_device_by_str(argv[0], argv[1], &desc);
>  	if (ret < 0)
>  		return 1;
>  
> -	err = part_get_info(desc, part, &info);
> -	if (err)
> -		return 1;
> +	part = simple_strtoul(argv[2], &endp, 0);
> +	if (*endp == '\0') {
> +		err = part_get_info(desc, part, &info);
> +		if (err)
> +			return 1;
> +	} else {
> +		part = part_get_info_by_name(desc, argv[2], &info);
> +		if (part == -1)
> +			return 1;
> +	}
>  
>  	snprintf(buf, sizeof(buf), LBAF, info.start);
>  
> @@ -147,6 +153,7 @@ static int do_part_size(int argc, char * const
> argv[]) struct blk_desc *desc;
>  	disk_partition_t info;
>  	char buf[512] = { 0 };
> +	char *endp;
>  	int part;
>  	int err;
>  	int ret;
> @@ -156,15 +163,20 @@ static int do_part_size(int argc, char * const
> argv[]) if (argc > 4)
>  		return CMD_RET_USAGE;
>  
> -	part = simple_strtoul(argv[2], NULL, 0);
> -
>  	ret = blk_get_device_by_str(argv[0], argv[1], &desc);
>  	if (ret < 0)
>  		return 1;
>  
> -	err = part_get_info(desc, part, &info);
> -	if (err)
> -		return 1;
> +	part = simple_strtoul(argv[2], &endp, 0);
> +	if (*endp == '\0') {
> +		err = part_get_info(desc, part, &info);
> +		if (err)
> +			return 1;
> +	} else {
> +		part = part_get_info_by_name(desc, argv[2], &info);
> +		if (part == -1)
> +			return 1;
> +	}
>  
>  	snprintf(buf, sizeof(buf), LBAF, info.size);
>  
> @@ -207,6 +219,8 @@ U_BOOT_CMD(
>  	"      flags can be -bootable (list only bootable
> partitions)\n" "part start <interface> <dev> <part> <varname>\n"
>  	"    - set environment variable to the start of the
> partition (in blocks)\n"
> +	"      part can be either partition number or partition
> name\n" "part size <interface> <dev> <part> <varname>\n"
> -	"    - set environment variable to the size of the partition
> (in blocks)"
> +	"    - set environment variable to the size of the partition
> (in blocks)\n"
> +	"      part can be either partition number or partition name"
>  );

Reviewed-by: Lukasz Majewski <lukma@denx.de>


Best regards,

Lukasz Majewski

--

DENX Software Engineering GmbH,      Managing Director: Wolfgang Denk
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: wd at denx.de
-------------- next part --------------
A non-text attachment was scrubbed...
Name: not available
Type: application/pgp-signature
Size: 488 bytes
Desc: OpenPGP digital signature
URL: <http://lists.denx.de/pipermail/u-boot/attachments/20180228/a9cf8067/attachment.sig>