Re: [Xen-devel] [PATCH V2 3/3] xen/arm: Add SCIFA UART support for early printk

[Julien Grall <julien.grall@xxxxxxx>]

On 22/02/2019 17:34, Oleksandr wrote:
> Hi, Julien
Hi Oleksandr,

> > > Your solution below require to overwrite EARLY_PRINTK_INC and not very easy 
> > > to extend of other version (e.g scifb). As I suggested earlier, we can 
> > > introduce an option the same way REG_SHIFT exist for 8250. The definition of 
> > > CONFIG_EARLY_PRINTK is:
> > > CONFIG_EARLY_PRINTK=<INC>,<BASE_ADDRESS>,<OTHER_OPTIONS>
> > >
> > > <OTHER_OPTIONS> would be the version. Nothing for SCIF and A for SCFIA.
> > >
> > > Then in Rules.mk, you would have something like:
> > >
> > > ifneq ($(word 3,$(EARLY_PRINTK_CFG)),)
> > > CFLAGS-y += -DCONFIG_EARLY_PRINTK_VERSION_$(word 3, $(EARLY_PRINTK_CFG)
> > > else
> > > CFLAGS-y += -DCONFIG_EARLY_PRINTK_VERSION_NONE
> > > endif
> > >
> > > debug-scif.inc would then contain:
> > >
> > > #ifdef CONFIG_EARLY_PRINTK_VERSION_A
> > > #define foo
> > > #define bar
> > > #elifdef CONFIG_EARLY_PRINTK_VERSION_NONE
> > > #define foo
> > > #define bar
> > > #endif
> > >
> > > The CONFIG_EARLY_PRINTK_VERSION_NONE is here to help catching new addition. 
> > > If someone if using a different version, it would not compile.
> > > Also, the code in Rules.mk is generic enough to extend for other version (e.g 
> > > scifb).
> > > Does it make sense?
> > Absolutely. Thank you
>
> Idea works as expected.
>
>
> Just a quick question.
>
> Shall I do this by a single patch or this should be spitted in two patches: 
> "reworking current code" followed by "adding SCIFA"?
Separate patch if possible. Thank you!

Cheers,

--
Julien Grall

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