From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753779AbbETOFh (ORCPT ); Wed, 20 May 2015 10:05:37 -0400 Received: from mailgw01.mediatek.com ([210.61.82.183]:46034 "EHLO mailgw01.mediatek.com" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1752896AbbETOFb (ORCPT ); Wed, 20 May 2015 10:05:31 -0400 X-Listener-Flag: 11101 Message-ID: <1432130725.20394.24.camel@mtksdaap41> Subject: Re: [PATCH v2 4/9] clocksource: mediatek: Use GPT as sched clock source From: Yingjoe Chen To: Matthias Brugger , Thomas Gleixner , Stephen Boyd CC: Mark Rutland , 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" , , "Sascha Hauer" , srv_heupstream , "linux-arm-kernel@lists.infradead.org" Date: Wed, 20 May 2015 22:05:25 +0800 In-Reply-To: References: <1431763110-443-1-git-send-email-yingjoe.chen@mediatek.com> <1431763110-443-5-git-send-email-yingjoe.chen@mediatek.com> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.2.3-0ubuntu6 Content-Transfer-Encoding: 7bit MIME-Version: 1.0 X-MTK: N Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 2015-05-20 at 13:02 +0200, 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. > ---- 8< ---------------- >8 ------ > From 631e7bf4e5d9456d0bb4a29b2dee4b84e8c052bd Mon Sep 17 00:00:00 2001 > From: Matthias Brugger > Date: Wed, 20 May 2015 12:43:16 +0200 > Subject: [PATCH] clocksource: mediatek: Define mtk_clock_event_device globally > > Sched clock code, especially sched_clock_register does not allow to pass a > pointer to actual_read_sched_clock. So if in the driver the register base > address is not globally defined, we are not able to read the scheduler > clock register. This patch sets the mtk_clock_event_device struct globally > for the driver, to be able to read the register. Hi, I'm not sure using a global device pointer is any better. Actually, almost every user of sched_clock_register need to keep a global register base address. Does it make sense to fix this in sched_clock_register? > Signed-off-by: Matthias Brugger > --- > drivers/clocksource/mtk_timer.c | 50 +++++++++++++++-------------------------- > 1 file changed, 18 insertions(+), 32 deletions(-) > > diff --git a/drivers/clocksource/mtk_timer.c b/drivers/clocksource/mtk_timer.c > index 68ab423..c5f5b40 100644 > --- a/drivers/clocksource/mtk_timer.c > +++ b/drivers/clocksource/mtk_timer.c > @@ -59,13 +59,9 @@ struct mtk_clock_event_device { > struct clock_event_device dev; > }; > > -static inline struct mtk_clock_event_device *to_mtk_clk( > - struct clock_event_device *c) > -{ > - return container_of(c, struct mtk_clock_event_device, dev); > -} > +struct mtk_clock_event_device *evt; The name is too short even if we make it static: static struct mtk_clock_event_device *evt __read_mostly; Joe.C