[PATCH 2/5] clocksource: mediatek: Use GPT as sched clock source

Yingjoe Chen
2015-07-13T09:32:46Z

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>
---
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