Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755405AbbGCPvq (ORCPT ); Fri, 3 Jul 2015 11:51:46 -0400 Received: from mail-wi0-f172.google.com ([209.85.212.172]:35901 "EHLO mail-wi0-f172.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754153AbbGCPvj (ORCPT ); Fri, 3 Jul 2015 11:51:39 -0400 From: Matthias Brugger To: Daniel Kurtz Cc: Yingjoe Chen , Mark Rutland , Thomas Gleixner , Russell King , Arnd Bergmann , Olof Johansson , "devicetree@vger.kernel.org" , Stephen Boyd , Pawel Moll , Catalin Marinas , Daniel Lezcano , "linux-kernel@vger.kernel.org" , Marc Carino , Rob Herring , linux-mediatek@lists.infradead.org, Sascha Hauer , srv_heupstream , "linux-arm-kernel@lists.infradead.org" Subject: Re: [PATCH v2 4/9] clocksource: mediatek: Use GPT as sched clock source Date: Fri, 03 Jul 2015 17:51:34 +0200 Message-ID: <1551938.VHQvCCENeg@ubix> User-Agent: KMail/4.13.3 (Linux/3.13.0-55-generic; KDE/4.13.3; x86_64; ; ) In-Reply-To: References: <1431763110-443-1-git-send-email-yingjoe.chen@mediatek.com> MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="us-ascii" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2878 Lines: 84 On Friday, July 03, 2015 09:48:42 PM Daniel Kurtz wrote: > On Wed, May 20, 2015 at 7:02 PM, Matthias Brugger > > wrote: > > 2015-05-16 9:58 GMT+02:00 Yingjoe Chen : > >> When cpu is in deep idle, arch timer will stop counting. Setup GPT as > >> sched clock source so it can keep counting in idle. > >> > >> Signed-off-by: Yingjoe Chen > >> --- > >> > >> drivers/clocksource/mtk_timer.c | 10 ++++++++++ > >> 1 file changed, 10 insertions(+) > >> > >> diff --git a/drivers/clocksource/mtk_timer.c > >> b/drivers/clocksource/mtk_timer.c index 91206f9..fe7cf72 100644 > >> --- a/drivers/clocksource/mtk_timer.c > >> +++ b/drivers/clocksource/mtk_timer.c > >> @@ -24,6 +24,7 @@ > >> > >> #include > >> #include > >> #include > >> > >> +#include > >> > >> #include > >> > >> #define GPT_IRQ_EN_REG 0x00 > >> > >> @@ -59,6 +60,13 @@ struct mtk_clock_event_device { > >> > >> struct clock_event_device dev; > >> > >> }; > >> > >> +static void __iomem *gpt_base __read_mostly; > >> + > >> +static u64 notrace mtk_read_sched_clock(void) > >> +{ > >> + return readl_relaxed(gpt_base + TIMER_CNT_REG(GPT_CLK_SRC)); > >> +} > >> + > >> > >> static inline struct mtk_clock_event_device *to_mtk_clk( > >> > >> struct clock_event_device *c) > >> > >> { > >> > >> @@ -243,6 +251,8 @@ static void __init mtk_timer_init(struct device_node > >> *node)>> > >> mtk_timer_setup(evt, GPT_CLK_SRC, TIMER_CTRL_OP_FREERUN, 1); > >> clocksource_mmio_init(evt->gpt_base + TIMER_CNT_REG(GPT_CLK_SRC), > >> > >> node->name, rate, 300, 32, > >> clocksource_mmio_readl_up); > >> > >> + gpt_base = evt->gpt_base; > > > > This is really hacky. We should clean up the code and provide > > mtk_clock_event_device globally. > > Please add the patch below, which does exactly this. > > I don't think this is so hacky. > In light of Stephen's comment about the benefit of using > container_of() to extract gpt_base from the passed in struct > clock_event_device in the other routines, what is the benefit of > making more of mtk_clock_event_device global? > I think what Yingjoe has implemented is short and sweet. > Huh, this patch got somehow forgotten. Ok, just one comment. I would prefer to rename the global gpt_base to gpt_sched_base or something similar and set the pointer + offset directly mtk_timer_init. Thanks, Matthias -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/