[PATCH] mmc: Change the frequency to MMC_HS_52 when selecting hs400

[Abbarapu, Venkatesh]

Do you have any comments for this patch?

Thanks
Venkatesh

> -----Original Message-----
> From: Venkatesh Yadav Abbarapu <venkatesh.abbarapu at amd.com>
> Sent: Tuesday, April 23, 2024 11:01 AM
> To: u-boot at lists.denx.de
> Cc: peng.fan at nxp.com; jh80.chung at samsung.com; git (AMD-Xilinx)
> <git at amd.com>
> Subject: [PATCH] mmc: Change the frequency to MMC_HS_52 when selecting
> hs400
> 
> Per JESD84-B51 P47, host need to change frequency to <=52MHz after setting
> HS_TIMING to 0x1, and host need to set the 8-bit DDR buswidth. Currently
> setting the frequency to 26MHz and trying to switch 8-bit DDR buswidth
> resulting timeouts.
> 
> mmc dev 1 0
> Select HS400 failed -110
> switch to partitions #0, OK
> mmc1(part 0) is current device
> 
> Signed-off-by: Venkatesh Yadav Abbarapu <venkatesh.abbarapu at amd.com>
> ---
>  drivers/mmc/mmc.c | 6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/mmc/mmc.c b/drivers/mmc/mmc.c index
> 7b068c71ff..a2ed99aefe 100644
> --- a/drivers/mmc/mmc.c
> +++ b/drivers/mmc/mmc.c
> @@ -962,8 +962,8 @@ static int mmc_set_card_speed(struct mmc *mmc,
> enum bus_mode mode,
>  	 * Extended CSD. Reconfigure the controller to run at HS mode.
>  	 */
>  	if (hsdowngrade) {
> -		mmc_select_mode(mmc, MMC_HS);
> -		mmc_set_clock(mmc, mmc_mode2freq(mmc, MMC_HS),
> false);
> +		mmc_select_mode(mmc, MMC_HS_52);
> +		mmc_set_clock(mmc, mmc_mode2freq(mmc, MMC_HS_52),
> false);
>  	}
>  #endif
> 
> @@ -2043,7 +2043,7 @@ static int mmc_select_hs400(struct mmc *mmc)
>  	}
> 
>  	/* Set back to HS */
> -	mmc_set_card_speed(mmc, MMC_HS, true);
> +	mmc_set_card_speed(mmc, MMC_HS_52, true);
> 
>  	err = mmc_hs400_prepare_ddr(mmc);
>  	if (err)
> --
> 2.17.1