Re: [PATCH v5 5/6] arm64: dts: cix: add initial CIX P1(SKY1) dts support

[Peter Chen]

On 25-03-25 10:52:10, Marc Zyngier wrote:
> > +     timer {
> > +             compatible = "arm,armv8-timer";
> > +             interrupt-names = "sec-phys", "phys", "virt", "hyp-phys", "hyp-virt";
> > +             interrupts = <GIC_PPI 13 IRQ_TYPE_LEVEL_LOW 0>,
> > +                          <GIC_PPI 14 IRQ_TYPE_LEVEL_LOW 0>,
> > +                          <GIC_PPI 11 IRQ_TYPE_LEVEL_LOW 0>,
> > +                          <GIC_PPI 10 IRQ_TYPE_LEVEL_LOW 0>,
> > +                          <GIC_PPI 12 IRQ_TYPE_LEVEL_LOW 0>;
> > +     };
> > +};
> 
> I don't think there is anything wrong here, but it is also a pretty
> useless DT. There isn't even a UART to interact with the machine and
> find out whether it has actually booted.
> 

UEFI uses the same UART, so we could see all kernel boot logs until
switch to use kernel UART driver for printk. If you would like boot
to the console at initramfs, just add uart node like patchset v1.

> I reckon this should be part of the initial DT, as this otherwise
> serves little purpose.
> 

Without this initial support, we can't add some base drivers, like
mailbox. The dt_binding_check will report warnings/errors [1].

Full UART support depends on clock, clock control needs mailbox
to talk with FW using SCMI protocol.

There is no any support for CIX SoC, so we had to add one small step by
step.

[1] https://lore.kernel.org/lkml/174290730775.1655008.14031380406017771195.robh@xxxxxxxxxx/

-- 

Best regards,
Peter