DEBUG_LL broken for socfpga

DEBUG_LL broken for socfpga

[Thomas Petazzoni]

Dinh,

The arch/arm/include/debug/socfpga.S file implements only addruart, and
forgets to implement waituart, senduart, busyuart:

  AS      arch/arm/kernel/debug.o
/home/thomas/projets/linux-2.6/arch/arm/kernel/debug.S: Assembler messages:
/home/thomas/projets/linux-2.6/arch/arm/kernel/debug.S:83: Error: bad instruction `waituart r2,r3'
/home/thomas/projets/linux-2.6/arch/arm/kernel/debug.S:84: Error: bad instruction `senduart r1,r3'
/home/thomas/projets/linux-2.6/arch/arm/kernel/debug.S:85: Error: bad instruction `busyuart r2,r3'

Since the socfpga UART is apparently 8250 compatible, adding:

#define UART_SHIFT      2
#include <asm/hardware/debug-8250.S>

at the end of socfpga.S should be sufficient. However, socfpga.S uses
an undefined DEBUG_LL_UART_OFFSET. And also most likely there is a
missing static mapping for the UART registers in
arch/arm/mach-socfpga/socfpga.c in order to get a virtual address for
the UART registers soon enough for earlyprintk to work.

Probably easy to fix, but I have no hardware and no datasheet.
Certainly better if someone having those could handle the
implementation of the fix.

Best regards,

Thomas
-- 
Thomas Petazzoni, Free Electrons
Kernel, drivers, real-time and embedded Linux
development, consulting, training and support.
http://free-electrons.com

DEBUG_LL broken for socfpga

[Dinh Nguyen]

Hi Thomas,

On Thu, 2012-10-25 at 18:18 +0200, Thomas Petazzoni wrote:
> Dinh,
> 
> The arch/arm/include/debug/socfpga.S file implements only addruart, and
> forgets to implement waituart, senduart, busyuart:
> 
>   AS      arch/arm/kernel/debug.o
> /home/thomas/projets/linux-2.6/arch/arm/kernel/debug.S: Assembler messages:
> /home/thomas/projets/linux-2.6/arch/arm/kernel/debug.S:83: Error: bad instruction `waituart r2,r3'
> /home/thomas/projets/linux-2.6/arch/arm/kernel/debug.S:84: Error: bad instruction `senduart r1,r3'
> /home/thomas/projets/linux-2.6/arch/arm/kernel/debug.S:85: Error: bad instruction `busyuart r2,r3'
> 
> Since the socfpga UART is apparently 8250 compatible, adding:
> 
> #define UART_SHIFT      2
> #include <asm/hardware/debug-8250.S>
> 
> at the end of socfpga.S should be sufficient. However, socfpga.S uses
> an undefined DEBUG_LL_UART_OFFSET. And also most likely there is a
> missing static mapping for the UART registers in
> arch/arm/mach-socfpga/socfpga.c in order to get a virtual address for
> the UART registers soon enough for earlyprintk to work.
> 
> Probably easy to fix, but I have no hardware and no datasheet.
> Certainly better if someone having those could handle the
> implementation of the fix.

Doesn't this patch address the fix?

in arm-soc for-next
commit  ef3f94412a4d7e107392e7c7cfc3e2d0668aa1aa


http://git.kernel.org/?p=linux/kernel/git/arm/arm-soc.git;a=commit;h=ef3f94412a4d7e107392e7c7cfc3e2d0668aa1aa


Thanks,
Dinh
> 
> Best regards,
> 
> Thomas

DEBUG_LL broken for socfpga

[Thomas Petazzoni]

Dinh,

On Thu, 25 Oct 2012 11:39:52 -0600, Dinh Nguyen wrote:

> Doesn't this patch address the fix?
> 
> in arm-soc for-next
> commit  ef3f94412a4d7e107392e7c7cfc3e2d0668aa1aa
> 
> http://git.kernel.org/?p=linux/kernel/git/arm/arm-soc.git;a=commit;h=ef3f94412a4d7e107392e7c7cfc3e2d0668aa1aa

Indeed, it fixes the problem. I was looking at 3.7-rc2, and forgot to
check in arm-soc/for-next before reporting the issue.

Sorry for the noise.

Thomas
-- 
Thomas Petazzoni, Free Electrons
Kernel, drivers, real-time and embedded Linux
development, consulting, training and support.
http://free-electrons.com