[PATCH] mmc: meson_gx_mmc: control ddr_mode bit

[Jaehoon Chung]

On 11/10/20 5:50 PM, Mark Kettenis wrote:
>> From: Neil Armstrong <narmstrong at baylibre.com>
>> Date: Tue, 10 Nov 2020 09:15:14 +0100
>>
>> On 10/11/2020 08:50, Jaehoon Chung wrote:
>>> EMMC_CFG register has a cfg_ddr bit(BIT[2]).
>>> It needs to set when mmc is running to ddr mode.
>>> Otherwise, its bit should be cleared.
>>> CFG_DDR[2] - 1: DDR mode, 0: SDR mode
>>>
>>> Signed-off-by: Jaehoon Chung <jh80.chung at samsung.com>
>>> ---
>>>  arch/arm/include/asm/arch-meson/sd_emmc.h | 1 +
>>>  drivers/mmc/meson_gx_mmc.c                | 5 +++++
>>>  2 files changed, 6 insertions(+)
>>>
>>> diff --git a/arch/arm/include/asm/arch-meson/sd_emmc.h b/arch/arm/include/asm/arch-meson/sd_emmc.h
>>> index 1e9f8cf498b4..c2f77c7308ec 100644
>>> --- a/arch/arm/include/asm/arch-meson/sd_emmc.h
>>> +++ b/arch/arm/include/asm/arch-meson/sd_emmc.h
>>> @@ -38,6 +38,7 @@
>>>  #define   CFG_BUS_WIDTH_1		0
>>>  #define   CFG_BUS_WIDTH_4		1
>>>  #define   CFG_BUS_WIDTH_8		2
>>> +#define   CFG_DDR_MODE			BIT(2)
>>>  #define   CFG_BL_LEN_MASK		GENMASK(7, 4)
>>>  #define   CFG_BL_LEN_SHIFT		4
>>>  #define   CFG_BL_LEN_512		(9 << 4)
>>> diff --git a/drivers/mmc/meson_gx_mmc.c b/drivers/mmc/meson_gx_mmc.c
>>> index 7c60e0566560..6fcf6c2ced27 100644
>>> --- a/drivers/mmc/meson_gx_mmc.c
>>> +++ b/drivers/mmc/meson_gx_mmc.c
>>> @@ -90,6 +90,11 @@ static int meson_dm_mmc_set_ios(struct udevice *dev)
>>>  	else
>>>  		return -EINVAL;
>>>  
>>> +	if (mmc->ddr_mode)
>>> +		meson_mmc_cfg |= CFG_DDR_MODE;
>>> +	else
>>> +		meson_mmc_cfg &= ~CFG_DDR_MODE;
>>> +
>>>  	/* 512 bytes block length */
>>>  	meson_mmc_cfg &= ~CFG_BL_LEN_MASK;
>>>  	meson_mmc_cfg |= CFG_BL_LEN_512;
>>>
>>
>> Interesting, how did it work without this bit ?
> 
> Well, in meson_mmc_probe() we have:
> 
>         cfg->host_caps = MMC_MODE_8BIT | MMC_MODE_4BIT |
> 	                MMC_MODE_HS_52MHz | MMC_MODE_HS;
> 
> So the driver doesn't advertise DDR support.

Right. I added some patch in my local for testing.

Actually, those is wrong. If want to follow linux driver, it needs to remove.
Instead, it has to use mmc_of_parse() for dt's property.

I will send patch after more test.

Best Regards,
Jaehoon Chung

>