From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757903Ab3FTPDe (ORCPT ); Thu, 20 Jun 2013 11:03:34 -0400 Received: from guitar.tcltek.co.il ([192.115.133.116]:44950 "EHLO sivan.tkos.co.il" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757693Ab3FTPDc (ORCPT ); Thu, 20 Jun 2013 11:03:32 -0400 Date: Thu, 20 Jun 2013 18:03:21 +0300 From: Baruch Siach To: Pavel Machek Cc: John Stultz , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, Ingo Molnar , Peter Zijlstra , Thomas Gleixner , Jamie Iles , Dinh Nguyen Subject: Re: [RFC PATCH 2/2] clocksource: dw_apb: allow build for architectures other than arm Message-ID: <20130620150321.GH10269@tarshish> References: <1369570367-994-2-git-send-email-baruch@tkos.co.il> <51A51271.2070506@linaro.org> <20130530053233.GL25186@sapphire.tkos.co.il> <20130620144432.GA22115@amd.pavel.ucw.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20130620144432.GA22115@amd.pavel.ucw.cz> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Pavel, On Thu, Jun 20, 2013 at 04:44:33PM +0200, Pavel Machek wrote: > > > >@@ -73,6 +77,9 @@ static void add_clocksource(struct device_node > > > > *source_timer) > > > > } > > > > static void __iomem *sched_io_base; > > > >+#ifndef CONFIG_HAVE_SETUP_SCHED_CLOCK > > > >+static u64 sched_clock_mult __read_mostly; > > > >+#endif > > > > static u32 read_sched_clock(void) > > > > { > > > >@@ -97,7 +104,11 @@ static void init_sched_clock(void) > > > > timer_get_base_and_rate(sched_timer, &sched_io_base, &rate); > > > > of_node_put(sched_timer); > > > >+#ifdef CONFIG_HAVE_SETUP_SCHED_CLOCK > > > > setup_sched_clock(read_sched_clock, 32, rate); > > > >+#else > > > >+ sched_clock_mult = NSEC_PER_SEC / rate; > > > >+#endif > > > > } > > > > > > Can you rework this to not use #ifdefs within the function? They > > > make it annoying to read the code. > > > > > > Instead maybe have a local setup_sched_clock() function that sets > > > the mult value for the !CONFIG_HAVE_SETUP_SCHED_CLOCK case? > > > > > > > static const struct of_device_id osctimer_ids[] __initconst = { > > > >@@ -124,3 +135,10 @@ void __init dw_apb_timer_init(void) > > > > init_sched_clock(); > > > > } > > > >+ > > > >+#ifndef CONFIG_HAVE_SETUP_SCHED_CLOCK > > > >+unsigned long long notrace sched_clock() > > > >+{ > > > >+ return read_sched_clock() * sched_clock_mult; > > > >+} > > > >+#endif > > > > > > Also, can you try to condense the number of #ifndef > > > CONFIG_HAVE_SETUP_SCHED_CLOCK checks to one, and consolidate the > > > needed functions all in that one conditional? > > > > Thanks for your comments. I'll rework the patch and resubmit. > > > > I've just noticed that I have a bigger problem. read_sched_clock() returns > > u32, not u64. This means that in a rate of, say, 100MHz it will wrap around > > after a little more than 40 seconds. Would it make sense to put ARM's 32 bin > > sched_clock extension code (arch/arm/kernel/sched_clock.c) is a common place > > (maybe drivers/clocksource), and use that? There seems to be nothing ARM > > specific in this code, after all. > > Also note that there are two conflicting changes to this area > pending. It seems one in soc-next arm tree will prevail. > > Please take a look... Now that generic sched_clock implementation is available to all architectures (38ff87f77 "sched_clock: Make ARM's sched_clock generic for all architectures" in the timers/core branch of the tip tree) this patch is not needed anymore. Thanks for the head up. baruch -- http://baruch.siach.name/blog/ ~. .~ Tk Open Systems =}------------------------------------------------ooO--U--Ooo------------{= - baruch@tkos.co.il - tel: +972.2.679.5364, http://www.tkos.co.il -