clocksource/drivers/mediatek: Use GPT as sched clock source

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@mediatek.com>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Acked-by: Stephen Boyd <sboyd@codeaurora.org>
Acked-by: Matthias Brugger <matthias.bgg@gmail.com>

diff --git a/drivers/clocksource/mtk_timer.c b/drivers/clocksource/mtk_timer.c
index c8badc427eec29e49bf29fd4fd62b7a1b179b3a0..fbfc74685e6afba837ae549021f7fe763f7c0de4 100644 (file)
--- 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)
 {
@@ -230,6 +238,8 @@ static void __init mtk_timer_init(struct device_node *node)
        mtk_timer_setup(evt, GPT_CLK_SRC, TIMER_CTRL_OP_FREERUN);
        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);