Re: Development tree for Cortex-A15?

[Jemma Jones <jemmajones81@xxxxxxxxxxx>]

> Subject: Re: Development tree for Cortex-A15?

> 
> On Fri, 4 May 2012 09:44:07 +0100 (BST), Jemma Jones
> <jemmajones81@xxxxxxxxxxx> wrote:
>>>  Subject: Re: Development tree for Cortex-A15?
>> 
>>> 
>>>  On Thu, 3 May 2012 14:35:55 +0100 (BST), Jemma Jones
>>>  <jemmajones81@xxxxxxxxxxx> wrote:
>>>>>   Subject: Re: Development tree for Cortex-A15?
>>>> 
>>>>   I'm currently on kvm-arm-v7-ael, because it looked like the 
> most
>>>>   up-to-date one. Which one should I be using for Cortex-A15 
> support?
>>> 
>>>  That branch is good enough, if you have a bleeding edge QEMU. Note that
>>>  the VE A15 support in that tree is DT only. I'm working on a v3.4 
> based
>>>  one
>>>  at the moment, but that's not completely ready yet.
>> 
>>  I'm just a little confused because under arch/arm/mach-vexpress/ there
> is
>>  no A15 tile? On the virtualopensystems.com git (which you quote above)
> you
>>  had to explicitly enable the board and it would show up in the .config
> as
>>  CONFIG_ARCH_VEXPRESS_CA15X4. Is that not the case anymore in your kernel
>>  tree?
> 
> No. The ARM tree in general is moving to the device tree, and
> CONFIG_ARCH_VEXPRESS_CA15X4 was always meant as a temporary hack until the
> VE-DT port was mature enough to be used.
> 
> As Paweł's DT work has been merged into 3.4, there is strictly no reason
> to keep this hack around, and my recent trees do reflect that fact
> (kvm-arm-v7-ael and kvm-arm-3.4). Christoffer may decide to keep this in
> his tree during a transition period, but CONFIG_ARCH_VEXPRESS_CA15X4 is
> dead as far as I am concerned.
> 
> If you're just starting to play with KVM-ARM now, please don't rely on 
> the
> A15 board file, it is a dead end.

What would be the correct configuration of low-level kernel debugging for the A15 board? I'd like to have earlyprintk etc working.

When I set it to 
Kernel low-level debugging port (No low-level debugging UART)

then I get the following error:

$ ARCH=arm make uImage
scripts/kconfig/conf --silentoldconfig Kconfig
#
# configuration written to .config
#
  CHK     include/linux/version.h
  CHK     include/generated/utsrelease.h
make[1]: `include/generated/mach-types.h' is up to date.
  CALL    scripts/checksyscalls.sh
  CHK     include/generated/compile.h
  AS      arch/arm/kernel/debug.o
In file included from arch/arm/kernel/debug.S:104:0:
arch/arm/mach-vexpress/include/mach/debug-macro.S:26:2: error: #error "Unknown vexpress UART offset"
make[1]: *** [arch/arm/kernel/debug.o] Error 1
make: *** [arch/arm/kernel] Error 2

If I just disable
[*] Kernel low-level debugging functions
then I don't seem to get any output at all.

What is the correct configuration?


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