[PATCH 1/3] rockchip: rk35xx: Remove use of eMMC DDR52 mode

[Quentin Schulz]

Hi Jonas,

On 1/27/24 12:15, Jonas Karlman wrote:
> Hi Eugen,
> 
> On 2024-01-27 04:48, Eugen Hristev wrote:
>> Hi Jonas,
>>
>>
>> On 1/27/24 01:26, Jonas Karlman wrote:
>>> Writing to eMMC using DDR52 mode does not work reliably or at all on
>>> RK356x and RK3588 boards.
>>>
>>
>>
>> This is related to the old issue I encountered last year with mmc write?
> 
> Yes, I think it is.
> 
> I did some testing on RK3566/RK3568/RK3588S/RK3588 boards with different
> eMMC modules with following result:
> 
> Read seem to work with all enabled modes:
> RK3566: MMC legacy, MMC High Speed (26MHz), MMC High Speed (52MHz),
>          MMC DDR52 (52MHz) and HS200 (200MHz)
> RK3568/RK3588S/RK3588: all above + HS400 (200MHz) and HS400ES (200MHz)
> 
> However, write had issues with some of the modes:
> MMC DDR52 (52MHz): all RK35xx
> HS400/HS400ES: only on RK3568 after changing hs400_txclk_tapnum to 8
> 
> HS200 seem to be the most stable write speed that worked on all SoCs.
> 
> So, dropping MMC DDR52 (52MHz) and enable use of HS200 (200MHz) seem to
> be the best option to get speedy and working read and write eMMC.
> 

1) we have this enabled on RK3588 Jaguar in upstream Linux... I may have 
improperly tested it then, would you mind sharing how you tested this 
mode on RK3588 so I can reproduce this and fix it on our product if 
we're impacted? I assume because we have HS200/HS400/HS400-ES enabled, 
DDR52 would never be used? (our eMMC is soldered and support the former 
modes).

2) Why are we not enabling HS400/HS400-ES for RK3588 boards? You seem to 
be saying there are issues with HS400/HS400-ES on RK3568 but you didn't 
mention the status for RK3588. Did I misunderstand the last sentence? 
Can you please rephrase in that case?

Cheers,
Quentin