[PATCH v4] mmc: Update environment variable with active partition

[Jaehoon Chung]

On 5/14/21 7:15 AM, Reuben Dowle wrote:
> This patch allows uboot scripts make choices about where to boot from based
> on the active mmc boot partition. This allows having two copies of kernel,
> filesystems etc, and choosing which to boot from based off of the active
> bootloader partition.
> 
> Signed-off-by: Reuben Dowle <reuben.dowle at 4rf.com>

Reviewed-by: Jaehoon Chung <jh80.chung at samsung.com>

Best Regards,
Jaehoon Chung

> ---
>  cmd/mmc.c         | 14 +++++++++-----
>  doc/usage/mmc.rst |  4 +++-
>  2 files changed, 12 insertions(+), 6 deletions(-)
> 
> diff --git a/cmd/mmc.c b/cmd/mmc.c
> index a10f137..b942576 100644
> --- a/cmd/mmc.c
> +++ b/cmd/mmc.c
> @@ -808,7 +808,7 @@ static int do_mmc_boot_resize(struct cmd_tbl *cmdtp, int flag,
>  	return CMD_RET_SUCCESS;
>  }
>  
> -static int mmc_partconf_print(struct mmc *mmc)
> +static int mmc_partconf_print(struct mmc *mmc, const char *varname)
>  {
>  	u8 ack, access, part;
>  
> @@ -821,6 +821,9 @@ static int mmc_partconf_print(struct mmc *mmc)
>  	ack = EXT_CSD_EXTRACT_BOOT_ACK(mmc->part_config);
>  	part = EXT_CSD_EXTRACT_BOOT_PART(mmc->part_config);
>  
> +	if(varname)
> +		env_set_hex(varname, part);
> +
>  	printf("EXT_CSD[179], PARTITION_CONFIG:\n"
>  		"BOOT_ACK: 0x%x\n"
>  		"BOOT_PARTITION_ENABLE: 0x%x\n"
> @@ -836,7 +839,7 @@ static int do_mmc_partconf(struct cmd_tbl *cmdtp, int flag,
>  	struct mmc *mmc;
>  	u8 ack, part_num, access;
>  
> -	if (argc != 2 && argc != 5)
> +	if (argc != 2 && argc != 3 && argc != 5)
>  		return CMD_RET_USAGE;
>  
>  	dev = simple_strtoul(argv[1], NULL, 10);
> @@ -850,8 +853,8 @@ static int do_mmc_partconf(struct cmd_tbl *cmdtp, int flag,
>  		return CMD_RET_FAILURE;
>  	}
>  
> -	if (argc == 2)
> -		return mmc_partconf_print(mmc);
> +	if (argc == 2 || argc == 3)
> +		return mmc_partconf_print(mmc, argc == 3 ? argv[2] : NULL);
>  
>  	ack = simple_strtoul(argv[2], NULL, 10);
>  	part_num = simple_strtoul(argv[3], NULL, 10);
> @@ -1061,8 +1064,9 @@ U_BOOT_CMD(
>  	" - Set the BOOT_BUS_WIDTH field of the specified device\n"
>  	"mmc bootpart-resize <dev> <boot part size MB> <RPMB part size MB>\n"
>  	" - Change sizes of boot and RPMB partitions of specified device\n"
> -	"mmc partconf <dev> [boot_ack boot_partition partition_access]\n"
> +	"mmc partconf <dev> [[varname] | [<boot_ack> <boot_partition> <partition_access>]]\n"
>  	" - Show or change the bits of the PARTITION_CONFIG field of the specified device\n"
> +	"   If showing the bits, optionally store the boot_partition field into varname\n"
>  	"mmc rst-function <dev> <value>\n"
>  	" - Change the RST_n_FUNCTION field of the specified device\n"
>  	"   WARNING: This is a write-once field and 0 / 1 / 2 are the only valid values.\n"
> diff --git a/doc/usage/mmc.rst b/doc/usage/mmc.rst
> index 57284ed..b72e5f8 100644
> --- a/doc/usage/mmc.rst
> +++ b/doc/usage/mmc.rst
> @@ -19,7 +19,7 @@ Synopsis
>      mmc wp
>      mmc bootbus <dev> <boot_bus_width> <reset_boot_bus_width> <boot_mode>
>      mmc bootpart-resize <dev> <dev part size MB> <RPMB part size MB>
> -    mmc partconf <dev> [boot_ack boot_partition partition_access]
> +    mmc partconf <dev> [[varname] | [<boot_ack> <boot_partition> <partition_access>]]
>      mmc rst-function <dev> <value>
>  
>  Description
> @@ -92,6 +92,8 @@ The 'mmc bootbus' command sets the BOOT_BUS_WIDTH field. (*Refer to eMMC specifi
>  
>  The 'mmc partconf' command shows or changes PARTITION_CONFIG field.
>  
> +    varname
> +        When showing the PARTITION_CONFIG, an optional environment variable to store the current boot_partition value into.
>      boot_ack
>          boot acknowledge value
>      boot_partition
>