From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753609AbbAICJ2 (ORCPT ); Thu, 8 Jan 2015 21:09:28 -0500 Received: from utopia.booyaka.com ([74.50.51.50]:35126 "EHLO utopia.booyaka.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752907AbbAICJ1 (ORCPT ); Thu, 8 Jan 2015 21:09:27 -0500 Date: Fri, 9 Jan 2015 02:09:25 +0000 (UTC) From: Paul Walmsley To: Daniel Lezcano cc: linux-kernel@vger.kernel.org, Thomas Gleixner , linux-tegra@vger.kernel.org, Allen Martin , Stephen Warren , Thierry Reding , Alexandre Courbot , pwalmsley@nvidia.com Subject: Re: [PATCH] clocksource: tegra: wrap arch/arm-specific sections in CONFIG_ARM In-Reply-To: <54AEB719.5060103@linaro.org> Message-ID: References: <54AEB719.5060103@linaro.org> User-Agent: Alpine 2.02 (DEB 1266 2009-07-14) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; CHARSET=US-ASCII Content-ID: Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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 > > #include > > > > +#ifdef CONFIG_ARM > > #include > > #include > > 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 removed 2. a larger number of changed lines, in order to minimize the number of new #ifdefs? - Paul