Messages in this thread | | | Date | Fri, 9 Jan 2015 02:09:25 +0000 (UTC) | From | Paul Walmsley <> | Subject | Re: [PATCH] clocksource: tegra: wrap arch/arm-specific sections in CONFIG_ARM |
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Hello Daniel
On Thu, 8 Jan 2015, Daniel Lezcano wrote:
> On 12/09/2014 11:07 PM, Paul Walmsley wrote: > > > > Like several of the other files in drivers/clocksource, > > tegra20_timer.c contains code that can only compile when CONFIG_ARM is > > enabled. This causes obvious problems when trying to compile this > > code for NVIDIA ARM64-based SoCs, such as Tegra132. The same timer IP > > blocks exist, so it seems appropriate to provide support for them. > > > > So until we figure out a better way to partition this code, wrap the > > delay_timer and persistent_clock support code with preprocessor tests > > for CONFIG_ARM. > > > > (The delay_timer code should not be needed at all on > > ARM64 due to the presence of the ARMv8 architected timer. The > > persistent_clock support code could become important once power > > management modes are implemented that turn off the CPU complex.) > > IIUC, the cpuidle driver is not yet ready, right ? > > If it is the case, this driver is not needed yet, no ?
The point of the patch is to allow the hardware drivers selected by CONFIG_ARCH_TEGRA to build for an arm64 kernel, just as they build for 32-bit ARM.
There's nothing CPUIdle-specific about the patch - that is, this timer can be selected as a clockevent and clocksource provider without the use of CPUIdle - although low-power PM idle is likely to be a primary use-case.
> Perhaps you can rework a bit this driver in the meantime to have a better fix > than disabling the code with macros ?
I'm happy to do that, but it would be nice to get the driver compiling first for ARM64 :-)
> Otherwise, please try at least to group the code into a minimal set of macros.
So, would it be accurate to say that you would prefer a patch that changes more lines of code, but minimizes preprocessor directives, to the current patch?
> One comment below.
> > diff --git a/drivers/clocksource/tegra20_timer.c > > b/drivers/clocksource/tegra20_timer.c > > index d2616ef16770..83a8f5c9e139 100644 > > --- a/drivers/clocksource/tegra20_timer.c > > +++ b/drivers/clocksource/tegra20_timer.c > > @@ -29,8 +29,10 @@ > > #include <linux/sched_clock.h> > > #include <linux/delay.h> > > > > +#ifdef CONFIG_ARM > > #include <asm/mach/time.h> > > #include <asm/smp_twd.h> > > Is smp_twd.h really needed ? > > > +#endif
No, it can be removed.
Would you be willing to ack or merge a revision of this patch with
1. the #include <asm/smp_twd.h> removed
2. a larger number of changed lines, in order to minimize the number of new #ifdefs?
- Paul
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