From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932328AbbAINYa (ORCPT ); Fri, 9 Jan 2015 08:24:30 -0500 Received: from mail-wi0-f172.google.com ([209.85.212.172]:56760 "EHLO mail-wi0-f172.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750785AbbAINY2 (ORCPT ); Fri, 9 Jan 2015 08:24:28 -0500 Message-ID: <54AFD688.5000304@linaro.org> Date: Fri, 09 Jan 2015 14:24:24 +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: Thierry Reding CC: Paul Walmsley , 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> <54AF91CC.2090007@linaro.org> <20150109122120.GJ16465@ulmo> In-Reply-To: <20150109122120.GJ16465@ulmo> 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 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_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. > > How about we do something like the attached patch instead for now. That > 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 the > ARM-specific parts and when the driver can build on 64-bit ARM we simply > select TEGRA_TIMER via Kconfig. Yes, that is exactly what I was thinking about after sending the previous email. And by this way, you also fixed the Kconfig option selection logic. -- Linaro.org │ Open source software for ARM SoCs Follow Linaro: Facebook | Twitter | Blog