From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932082AbbAIIbO (ORCPT ); Fri, 9 Jan 2015 03:31:14 -0500 Received: from mail-wg0-f41.google.com ([74.125.82.41]:64322 "EHLO mail-wg0-f41.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753742AbbAIIbM (ORCPT ); Fri, 9 Jan 2015 03:31:12 -0500 Message-ID: <54AF91CC.2090007@linaro.org> Date: Fri, 09 Jan 2015 09:31:08 +0100 From: Daniel Lezcano User-Agent: Mozilla/5.0 (X11; Linux i686; rv:31.0) Gecko/20100101 Thunderbird/31.3.0 MIME-Version: 1.0 To: Paul Walmsley 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 References: <54AEB719.5060103@linaro.org> In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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 >>> #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? Yes. Thanks -- Daniel -- Linaro.org │ Open source software for ARM SoCs Follow Linaro: Facebook | Twitter | Blog