Messages in this thread | | | Date | Fri, 09 Jan 2015 09:31:08 +0100 | From | Daniel Lezcano <> | Subject | Re: [PATCH] clocksource: tegra: wrap arch/arm-specific sections in CONFIG_ARM |
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On 01/09/2015 03:09 AM, Paul Walmsley wrote: > 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.
What I meant is this timer is not needed for the moment.
>> 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?
Yes at least an attempt to factor out a bit the driver. Those #ifdef are like #if 0, which is a quick fix. I am not strongly against this patch, but it would be nice to take the opportunity to reorganize it a bit.
>> 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?
Yes.
Thanks
-- Daniel
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