From mboxrd@z Thu Jan 1 00:00:00 1970 From: djkurtz@chromium.org (Daniel Kurtz) Date: Fri, 3 Jul 2015 21:48:42 +0800 Subject: [PATCH v2 4/9] clocksource: mediatek: Use GPT as sched clock source In-Reply-To: References: <1431763110-443-1-git-send-email-yingjoe.chen@mediatek.com> <1431763110-443-5-git-send-email-yingjoe.chen@mediatek.com> Message-ID: To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org 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. Reviewed-by: Daniel Kurtz