[PATCH v1 1/1] arm64: zynqmp: Fix k24 psu_init_gpl.c clocking

[Frager, Neal]

Hi Michal,

> 
>> This patch corrects the k24 som clocking configuration such that the serdes
> 
>> Corrects the ...
> 
> Ok.
> 
>> clocks are correctly enabled and the usb0 is configured to use the psgtr
>> refclk2 for usb3 mode.
> 
>> I sort of have no problem with this patch but it should be better described.
>> Pretty much serdes configuration should be called from u-boot because we already
>> have psgtr driver and usb3.0 can be configured out of it.
>> But we can't touch dwc3 driver now that's why the only way to do it is to
>> configure via psu_init.
>> But it should be clear from commit message that it is workaround not really
>> something what should be here.
> 
> I will re-test this without the serdes additions to see if they are
> really necessary.
> 
>> This patch also corrects the configuration of mio pins mio76 and mio77
>> which should be configured as gpio pins.
> 
>> This is definitely fine.
> 
> Good.
> 
>>
>> Signed-off-by: Neal Frager <neal.frager at amd.com>
> 
>> You mentioned that SPL didn't work before. Is it because of incorrect serdes
>> configuration? Because that's sounds weird because you don't need serdes
>> initialization for booting out of qspi. That's why looking for which is that bit
>> which make SPL work on KD240.
> 
> The SPL works.  The issue is the same as I had with the kr260
> board.  The sd card interface is over usb, so unless the usb3
> works correctly, u-boot has no sd card interface and cannot
> find the Linux kernel and file system.
> 
> So what I meant was that I cannot boot up properly
> when starting from the SPL.  This is what this patch is
> meant to fix.

> What I have seen on KD240 was that I could get to u-boot prompt. And for that 
> you don't need any serdes initialization at all.

Yes, agreed.  I can get to u-boot prompt too without
any additional patches.

> For booting OS you need it if you want to use USB3.0.

And for the kd240, sd card requires usb3.0 also.

> That's why I want to make it clear what makes kd240 to boot u-boot.
> And what makes to access sd over usb to boot OS.

Understood.  The issue I am trying to solve is enabling
sd over usb to boot OS.

> And no issue to add serdes initialization to psu_init to get boot OS part to 
> work till someone has time to wire psgtr driver with dwc3 to configure it at run 
> time.

Is someone currently working on wiring psgtr driver with dwc3?

If this were to happen soon, than this psu_init_gpl.c patch
would become unnecessary.

Best regards,
Neal Frager
AMD