[U-Boot] [PATCH 1/2] cmd_mmc: default to HW partition 0 if not specified

[Pantelis Antoniou]

Hi Stephen,

On May 23, 2014, at 9:48 PM, Stephen Warren wrote:

> From: Stephen Warren <swarren at nvidia.com>
> 
> Currently, "mmc dev 0" does not change the selected HW partition. I
> think it makes more sense if "mmc dev 0" is an alias for "mmc dev 0 0",
> i.e. that HW partition 0 (main data area) is always selected by default
> if the user didn't request a specific partition. Otherwise, the following
> happens, which feels wrong:
> 
> Select HW partition 1 (boot0):
> mmc dev 0 1
> 
> Doesn't change the HW partition, so it's still 1 (boot0):
> mmc dev 0
> 
> With this patch, the second command above re-selects the main data area.
> 
> Note that some MMC devices (i.e. SD cards) don't support HW partitions.
> However, this patch still works, since mmc_start_init() sets the current
> partition number to 0, and mmc_select_hwpart() succeeds if the requested
> partition is already selected.
> 
> Signed-off-by: Stephen Warren <swarren at nvidia.com>
> ---
> This series depends on "mmc: return meaningful error codes from
> mmc_select_hwpart" (which I just sent) for context.
> 
> common/cmd_mmc.c | 15 +++++++--------
> 1 file changed, 7 insertions(+), 8 deletions(-)
> 
> diff --git a/common/cmd_mmc.c b/common/cmd_mmc.c
> index eea337506c3f..9e6a26fe62a2 100644
> --- a/common/cmd_mmc.c
> +++ b/common/cmd_mmc.c
> @@ -403,7 +403,7 @@ static int do_mmc_part(cmd_tbl_t *cmdtp, int flag,
> static int do_mmc_dev(cmd_tbl_t *cmdtp, int flag,
> 		      int argc, char * const argv[])
> {
> -	int dev, part = -1, ret;
> +	int dev, part = 0, ret;
> 	struct mmc *mmc;
> 
> 	if (argc == 1) {
> @@ -426,13 +426,12 @@ static int do_mmc_dev(cmd_tbl_t *cmdtp, int flag,
> 	if (!mmc)
> 		return CMD_RET_FAILURE;
> 
> -	if (part != -1) {
> -		ret = mmc_select_hwpart(dev, part);
> -		printf("switch to partitions #%d, %s\n",
> -			part, (!ret) ? "OK" : "ERROR");
> -		if (ret)
> -			return 1;
> -	}
> +	ret = mmc_select_hwpart(dev, part);
> +	printf("switch to partitions #%d, %s\n",
> +	       part, (!ret) ? "OK" : "ERROR");
> +	if (ret)
> +		return 1;
> +
> 	curr_device = dev;
> 	if (mmc->part_config == MMCPART_NOAVAILABLE)
> 		printf("mmc%d is current device\n", curr_device);
> -- 
> 1.8.1.5

There's a small behavioral change (always selecting a hardware partition when selecting a device), 
but there shouldn't be any users that care about it.

Thanks, applied.

-- Pantelis

Acked-by: Pantelis Antoniou <panto at antoniou-consulting.com>