Re: [PATCH 13/18] rockchip: rk3588: fix non-working SD controller if booting from other media

[Dragan Simic <dsimic@manjaro.org>]

On 2024-01-26 12:29, Quentin Schulz wrote:
> On 1/26/24 12:24, Dragan Simic wrote:
>> On 2024-01-26 12:09, Quentin Schulz wrote:
>>> On 1/26/24 12:04, Dragan Simic wrote:
>>>> On 2024-01-26 11:37, Quentin Schulz wrote:
>>>>> On 1/26/24 03:57, Kever Yang wrote:
>>>>>> On 2024/1/25 19:02, Quentin Schulz wrote:
>>>>>>> We don't have a dedicated CD pin for the SD card connector.
>>>>>>> https://www.digikey.com/en/products/detail/molex/0472192001/3044807
>>>>>>> is the SD card connector we use.
>>>>>> 
>>>>>> Thanks for your information, but I think you are using the wrong
>>>>>> microSD connector for rk3588 and maybe also for other rockchip 
>>>>>> SoCs.
>>>>>> Here are four microSD card connector from the web you provide, all
>>>>>> of
>>>>>> them have card detect signal available for pcb:
>>>>>> https://www.digikey.com/en/product-highlight/m/molex-connector/sd-memory-card-connectors
>>>>> 
>>>>> None of those fit our requirements. We need a safe system that
>>>>> doesn't
>>>>> break because of vibrations or shocks. Push-pull connectors are out
>>>>> of
>>>>> question for our design. We have had issues with our Q7 devkit with
>>>>> push-pull connector with SD cards slightly smaller or inserted
>>>>> somewhat the wrong way. I can recall also countless of discussions 
>>>>> in
>>>>> the early days of the Raspberry Pis where there were a lot of 
>>>>> issues
>>>>> related to SD cards.
>>>>> 
>>>>> This is basically the mechanism we are using
>>>>> https://media.distrelec.com/Web/WebShopImages/landscape_large/4-/01/Molex-500901-0801-30161714-01.jpg
>>>> 
>>>> Please, allow me to interject...  I'm really curious why don't you
>>>> use eMMC chips instead of microSD cards?  I mean, if the reliability
>>>> is of utmost importance, I wouldn't even consider microSD cards, not
>>>> even the high-endurance variants.
>>> 
>>> We have both :)
>> 
>> Ah, I see. :)  Perhaps my question wasn't precise enough;  actually,
>> now I'd like to know what do you use as the primary storage for the
>> operating system installation -- eMMC chip or microSD cards?  Is the
>> eMMC chip soldered?  I'm just curious. :)
>> 
> Soldered eMMC is the primary (expected) storage. If both eMMC and SD
> card are inserted and properly flashed, it'll boot from eMMC except if
> the BIOS button is pressed, in which case SD card will be selected
> instead. If SD card is missing/improperly flashed, it'll boot into USB
> flashing mode (rkdeveloptool/rockusb) if the BIOS button is pressed
> (similar to when no storage media is properly flashed).

Thanks for the clarification.  Just one more question, please:  is the
BIOS button handled in software (i.e. in U-Boot), or does it disable the
eMMC chip by shorting its clock or a data line to ground?