Re: [Xen-devel] [PATCH V2 2/2] xen: arm: implement early prink for 8250 uart

[Ian Campbell <Ian.Campbell@xxxxxxxxxx>]

On Wed, 2013-07-03 at 19:50 +0800, Chen Baozi wrote:
> On Tue, 2013-07-02 at 21:11 +0800, Bamvor Jian Zhang wrote:
> 
> > implement early printk for 8250 uart which is used by lots of arm SOC, such 
> > as
> > Allwinner A31(sun6i) and OMAP5432.
> > 
> > Signed-off-by: Bamvor Jian Zhang <bjzhang@xxxxxxxx>
> > ---
> >  docs/misc/arm/early-printk.txt    |  1 +
> >  xen/arch/arm/Rules.mk             |  5 ++++
> >  xen/arch/arm/arm32/debug-8250.inc | 48 
> > +++++++++++++++++++++++++++++++++++++++
> >  3 files changed, 54 insertions(+)
> >  create mode 100644 xen/arch/arm/arm32/debug-8250.inc
> > 
> > diff --git a/docs/misc/arm/early-printk.txt b/docs/misc/arm/early-printk.txt
> > index fbc3208..eaa66a1 100644
> > --- a/docs/misc/arm/early-printk.txt
> > +++ b/docs/misc/arm/early-printk.txt
> > @@ -13,6 +13,7 @@ where mach is the name of the machine:
> >    - exynos5250: printk with the second UART
> >    - midway: printk with the pl011 on Calxeda Midway processors
> >    - fastmodel: printk on ARM Fastmodel software emulators
> > +  - sun6i: printk with 8250 on Allwinner A31 processors
> Could this be better to add:
> 
>     - omap5432: printk with 8250 compatible UART on OMAP5432 processors
> 
> >  
> >  The base address and baud rate is hardcoded in xen/arch/arm/Rules.mk,
> >  see there when adding support for new machines.
> > diff --git a/xen/arch/arm/Rules.mk b/xen/arch/arm/Rules.mk
> > index 422ed04..51e823d 100644
> > --- a/xen/arch/arm/Rules.mk
> > +++ b/xen/arch/arm/Rules.mk
> > @@ -64,6 +64,11 @@ EARLY_PRINTK_INC := pl011
> >  EARLY_PRINTK_BAUD := 115200
> >  EARLY_UART_BASE_ADDRESS := 0xfff36000
> >  endif
> > +ifeq ($(CONFIG_EARLY_PRINTK), sun6i)
> > +# uart configured at 115200 by bootloader
> > +EARLY_PRINTK_INC := 8250
> > +EARLY_UART_BASE_ADDRESS := 0x01c28000
> > +endif
> 
> EARLY_UART_BASE_ADDRESS on OMAP5432 is 0x48020000, so I think we'd
> better to add another case to support it?

Yes, this is exactly what should happen. You could either send a patch
on top of Bamvor's or perhaps he would be willing to integrate these
bits into his existing patch.

>  For example:
> 
> +ifeq ($(CONFIG_EARLY_PRINTK), omap5432)
> +# uart configured at 115200 by bootloader
> +EARLY_PRINTK_INC := 8250
> +EARLY_UART_BASE_ADDRESS := 0x48020000
> +endif

Ian.


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