[PATCH] pxa/zeus: Allow use of 8250-compatible UART in uncompress

[Marc Zyngier]

On Thu, 10 Dec 2009 15:12:08 +0800
Daniel Mack <daniel at caiaq.de> wrote:

> On Thu, Dec 10, 2009 at 07:39:22AM +0100, Marc Zyngier wrote:
> > Zeus console port is wired to a 8250-compatible device
> > (pxa UARTs are reserved to other uses). This patch
> > allows such a configuration in the uncompress sequence.
> 
> Was that tested for regressions with PXA UARTs?

Indeed. Tested with an Arcom Viper (PXA-255, console on FFUART). I
should have mentioned it in the commit message...

> I didn't, but ...
> 
> > diff --git a/arch/arm/mach-pxa/include/mach/uncompress.h
> > b/arch/arm/mach-pxa/include/mach/uncompress.h index
> > 237734b..dc94a34 100644 ---
> > a/arch/arm/mach-pxa/include/mach/uncompress.h +++
> > b/arch/arm/mach-pxa/include/mach/uncompress.h @@ -13,17 +13,21 @@
> >  #include <mach/regs-uart.h>
> >  #include <asm/mach-types.h>
> >  
> > -#define __REG(x)       ((volatile unsigned long *)x)
> > +#define __REG(x)       ((volatile char *)x)
> >  
> > -static volatile unsigned long *UART = FFUART;
> > +static volatile char *UART = FFUART;
> > +static int shift = 2;
> > +static int is_pxa_uart = 1;
> > +
> > +#define UART_REG(x)	UART[(x) << shift]
> 
> ... with UART being char* now (and as UART_REG is just a macro) it
> will only be 8 bits in width, and hence all logic that accesses bits
> beyond that scope wil fail. Tricky casting might help here, but your
> referencing that as an array, so the value will be &= 0xff.
> Or did I overlook anything?

Well, all registers are actually 8bit wide. So I feel like using char*
is actually one step closer to the actual behavior of the hardware.
Unless I in turn overlooked something else... ;-)

	M.
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