Help with u-boot when using the eMMC card in DDR mode

[Jaehoon Chung]

Hi,

On 7/26/21 4:41 PM, Abder wrote:
> Hi,
> 
> I have been trying recently to optimize the boot time on a customized board
> based on the IMX6DP.
> 
> For the time being, I succeeded in enabling the DDR (dual data rate) mode
> for the emmc to speed up the data rate for read and write cycles in u-boot.
> 
> By reading a file from the emmc using the "load" command (e.g. load mmc 2:1
> 0x12000000 file), I can see that the data rate has doubled, confirming that
> the DDR mode is enabled.
> 
> However, the problem I have is that when I execute the u-boot command "mmc
> dev 2" to switch the current device to the onboard eMMC, the command fails
> with the output below : (with DEBUG enabled)

If you can enable CONFIG_MMC_TRACE, then you can get more information relevant to MMC.
Could you also share log after enabled MMC_TRACE?

Best Regards,
Jaehoon Chung

> 
> U-Boot >mmc dev 2
> blk_find_device: if_type=6, devnum=2: usdhc at 02198000.blk, 6, 2
> ofnode_read_u32: vmmc-supply: 0x33 (51)
> ofnode_read_u32: vqmmc-supply: 0x33 (51)
> clock is disabled (0Hz)
> fixed_regulator_set_enable: dev='3p3v', enable=1, delay=0, has_gpio=0
> clock is enabled (400000Hz)
> Command failed, result=1
> U-Boot >
> 
> and after this command, any attempt to interact with the emmc (e.g. fatls
> mmc 2:1 ) ends with failure.
> 
> To enable the DDR mode, all I did was define the macro
> CONFIG_SYS_FSL_ESDHC_HAS_DDR_MODE in the header of my board.
> 
> Any help is greatly appreciated !
> 
> --
> 
> Abder,
>