[Letux-kernel] X1600 / LX16 support - here: adding MMC

Paul Boddie paul at boddie.org.uk
Fri Feb 9 18:12:09 CET 2024


On Friday, 9 February 2024 15:14:11 CET H. Nikolaus Schaller wrote:
> 
> So it will indeed be interesting to see how the MSC registers are
> initialized. And clock dividers and registers. And pinctrl. Will just need
> a little time for hacking this into the kernel code.

U-Boot does set up the pins for MSC0 and obviously transfers the boot payload, 
but as previously noted it also sets low power mode (LPM), and this might be 
obstructing any device clock operations that take place without being aware of 
the stated effects of LPM.

However, I have been working through the initialisation separately and have 
found that, in contrast to various earlier SoCs, there is a timeout interrupt 
that needs to be tested for. This is actually done in the U-Boot code. I was 
previously assuming that it was sufficient to test for the end-of-command 
interrupt, but this occurs even if there is a timeout: it doesn't indicate a 
successful response.

So, there may be some differences in functionality that need to be introduced.

Paul




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