[PATCH 2/5] clocksource: mediatek: Use GPT as sched clock source
From: Yingjoe Chen <hidden>
Date: 2015-07-13 09:33:49
Also in:
linux-arm-kernel, linux-clk, linux-devicetree, lkml
Subsystem:
clocksource, clockevent drivers, the rest · Maintainers:
Daniel Lezcano, Thomas Gleixner, Linus Torvalds
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 <yingjoe.chen-NuS5LvNUpcJWk0Htik3J/w@public.gmane.org> --- 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 237c20b..ae95b29 100644
--- a/drivers/clocksource/mtk_timer.c
+++ b/drivers/clocksource/mtk_timer.c@@ -24,6 +24,7 @@ #include <linux/of.h> #include <linux/of_address.h> #include <linux/of_irq.h> +#include <linux/sched_clock.h> #include <linux/slab.h> #define GPT_IRQ_EN_REG 0x00
@@ -59,6 +60,13 @@ struct mtk_clock_event_device { struct clock_event_device dev; }; +static void __iomem *gpt_sched_reg __read_mostly; + +static u64 notrace mtk_read_sched_clock(void) +{ + return readl_relaxed(gpt_sched_reg); +} + static inline struct mtk_clock_event_device *to_mtk_clk( struct clock_event_device *c) {
@@ -242,6 +250,8 @@ static void __init mtk_timer_init(struct device_node *node) mtk_timer_setup(evt, GPT_CLK_SRC, TIMER_CTRL_OP_FREERUN, true); clocksource_mmio_init(evt->gpt_base + TIMER_CNT_REG(GPT_CLK_SRC), node->name, rate, 300, 32, clocksource_mmio_readl_up); + gpt_sched_reg = evt->gpt_base + TIMER_CNT_REG(GPT_CLK_SRC); + sched_clock_register(mtk_read_sched_clock, 32, rate); /* Configure clock event */ mtk_timer_setup(evt, GPT_CLK_EVT, TIMER_CTRL_OP_REPEAT, false);
--
1.8.1.1.dirty
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