From mboxrd@z Thu Jan 1 00:00:00 1970 From: Daniel Lezcano Subject: Re: [PATCH] clocksource: tegra: wrap arch/arm-specific sections in CONFIG_ARM Date: Fri, 09 Jan 2015 14:24:24 +0100 Message-ID: <54AFD688.5000304@linaro.org> References: <54AEB719.5060103@linaro.org> <54AF91CC.2090007@linaro.org> <20150109122120.GJ16465@ulmo> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: In-Reply-To: <20150109122120.GJ16465@ulmo> Sender: linux-tegra-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Thierry Reding Cc: Paul Walmsley , linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Thomas Gleixner , linux-tegra-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Allen Martin , Stephen Warren , Thierry Reding , Alexandre Courbot , pwalmsley-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org List-Id: linux-tegra@vger.kernel.org On 01/09/2015 01:21 PM, Thierry Reding wrote: > On Fri, Jan 09, 2015 at 09:31:08AM +0100, Daniel Lezcano wrote: >> 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_A= RM is >>>>> enabled. This causes obvious problems when trying to compile thi= s >>>>> code for NVIDIA ARM64-based SoCs, such as Tegra132. The same tim= er IP >>>>> blocks exist, so it seems appropriate to provide support for them= =2E >>>>> >>>>> So until we figure out a better way to partition this code, wrap = the >>>>> delay_timer and persistent_clock support code with preprocessor t= ests >>>>> 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 ti= mer can >>> be selected as a clockevent and clocksource provider without the us= e 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 compil= ing >>> first for ARM64 :-) >>> >>>> Otherwise, please try at least to group the code into a minimal se= t 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 c= urrent >>> 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 pat= ch, but >> it would be nice to take the opportunity to reorganize it a bit. > > How about we do something like the attached patch instead for now. Th= at > avoids any #ifdef'ery and still we don't attempt (and fail) to build = the > driver on 64-bit ARM. > > With that applied we can incrementally make the changes to untangle t= he > ARM-specific parts and when the driver can build on 64-bit ARM we sim= ply > select TEGRA_TIMER via Kconfig. Yes, that is exactly what I was thinking about after sending the=20 previous email. And by this way, you also fixed the Kconfig option=20 selection logic. --=20 Linaro.org =E2=94=82 Open source software fo= r ARM SoCs =46ollow Linaro: Facebook | Twitter | Blog