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

[Quentin Schulz]

Hi Dragan,

On 1/26/24 12:33, Dragan Simic wrote:
> 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?

None of those options :)

On RK3588, the boot media selection and order is done via the channel 0 
of the SARADC. So a specific voltage is provided to boot from eMMC or 
from SD card.

Quentin