[PATCH 6/6] ARM:Gemini:add timer3 as sched_clock_source

From: Hans Ulli Kroll
Date: Fri Jun 05 2015 - 23:59:16 EST


This patch is based on openwrt patch found in
target/linux/gemini/patches-3.18/160-gemini-timers.patch

It setups a free running timer (timer3) for scheduler clock

Signed-off-by: Hans Ulli Kroll <ulli.kroll@xxxxxxxxxxxxxx>
---
arch/arm/mach-gemini/time.c | 20 ++++++++++++++++++++
1 file changed, 20 insertions(+)

diff --git a/arch/arm/mach-gemini/time.c b/arch/arm/mach-gemini/time.c
index 29ec2c3..e419dd4 100644
--- a/arch/arm/mach-gemini/time.c
+++ b/arch/arm/mach-gemini/time.c
@@ -15,6 +15,8 @@
#include <asm/mach/time.h>
#include <linux/clockchips.h>
#include <linux/clocksource.h>
+#include <linux/sched_clock.h>
+

/*
* Register definitions for the timers
@@ -58,6 +60,11 @@

static unsigned int tick_rate;

+static u64 notrace gemini_read_sched_clock(void)
+{
+ return readl(TIMER_COUNT(GEMINI_TIMER3_BASE));
+}
+
static int gemini_timer_set_next_event(unsigned long cycles,
struct clock_event_device *evt)
{
@@ -196,6 +203,19 @@ void __init gemini_timer_init(void)
TIMER_CR);

/*
+ * Setup free-running clocksource timer (interrupts
+ * disabled.)
+ */
+ writel(0, TIMER_COUNT(GEMINI_TIMER3_BASE));
+ writel(0, TIMER_LOAD(GEMINI_TIMER3_BASE));
+ writel(0, TIMER_MATCH1(GEMINI_TIMER3_BASE));
+ writel(0, TIMER_MATCH2(GEMINI_TIMER3_BASE));
+ clocksource_mmio_init(TIMER_COUNT(GEMINI_TIMER3_BASE),
+ "gemini_clocksource", tick_rate,
+ 300, 32, clocksource_mmio_readl_up);
+ sched_clock_register(gemini_read_sched_clock, 32, tick_rate);
+
+ /*
* Setup clockevent timer (interrupt-driven.)
*/
writel(0, TIMER_COUNT(GEMINI_TIMER1_BASE));
--
2.4.2

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