Re: [PATCH v3 9/9] ARM: add initial support for Marvell Berlin SoCs

[Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com>]

On 11/07/2013 05:20 PM, Arnd Bergmann wrote:
> On Thursday 07 November 2013, Sebastian Hesselbarth wrote:
>> Actually, IIRC smp_twd does not compile without SMP set, so the above
>> should at least be 'HAVE_ARM_TWD if SMP'. If you shrink MULTI_V7 down
>> to non-SMP cores, you can disable it and it will fail to compile.
>
> If there are UP-systems for which TWD is the best clocksource, we should
> probably fix the code to allow that configuration. IIRC there were already
> patches recently in this area, maybe it's already solved.

I just tried barebox bootloader to use TWD as timer on berlin2cd and it
perfectly works, i.e. with time related commands I can see the timer
register decreasing. So the timer is available on this UP SoC.

As said before, compiling linux without CONFIG_SMP but with
CONFIG_HAVE_ARM_TWD gives:

warning: (SOC_OMAP5 && ARCH_ROCKCHIP && ARCH_SHMOBILE_MULTI && 
MACH_BERLIN_BG2 && MACH_BERLIN_BG2CD) selects HAVE_ARM_TWD which has 
unmet direct dependencies (SMP)

and

arch/arm/kernel/smp_twd.c: In function 'twd_local_timer_of_register':
arch/arm/kernel/smp_twd.c:391: error: 'setup_max_cpus' undeclared (first 
use in this function)
arch/arm/kernel/smp_twd.c:391: error: (Each undeclared identifier is 
reported only once
arch/arm/kernel/smp_twd.c:391: error: for each function it appears in.)
make[1]: *** [arch/arm/kernel/smp_twd.o] Error 1

I haven't looked deeper into this, but I guess it will not be hard
to make ARM_TWD independent of SMP.

Sebastian