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authorRussell King <rmk+kernel@arm.linux.org.uk>2015-10-19 18:19:20 +0300
committerDaniel Lezcano <daniel.lezcano@linaro.org>2015-10-19 23:42:14 +0300
commitcb0f2538039c65f2bb64a9d427dbe9dd7d0f71a6 (patch)
treea6996906da3f837f4b5a2d9c84fd91a81d1fb341 /drivers/clocksource
parentccd63ce471c9b69663783e919ca4dba9967cd690 (diff)
downloadlinux-cb0f2538039c65f2bb64a9d427dbe9dd7d0f71a6.tar.xz
clocksource/drivers/armada-370-xp: Implement ARM delay timer
Implement an ARM delay timer to be used for udelay() on Armada 37x platforms. This allows us to skip the delay loop calibration at boot, saving 180ms on the boot time of the kernel (which is around 10%). It also means that udelay() will be unaffected by CPU frequency changes when cpufreq is enabled on these platforms. Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk> Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org> Tested-by: Gregory CLEMENT <gregory.clement@free-electrons.com> Acked-by: Gregory CLEMENT <gregory.clement@free-electrons.com>
Diffstat (limited to 'drivers/clocksource')
-rw-r--r--drivers/clocksource/time-armada-370-xp.c14
1 files changed, 14 insertions, 0 deletions
diff --git a/drivers/clocksource/time-armada-370-xp.c b/drivers/clocksource/time-armada-370-xp.c
index 2162796fd504..d93ec3c4f139 100644
--- a/drivers/clocksource/time-armada-370-xp.c
+++ b/drivers/clocksource/time-armada-370-xp.c
@@ -45,6 +45,8 @@
#include <linux/percpu.h>
#include <linux/syscore_ops.h>
+#include <asm/delay.h>
+
/*
* Timer block registers.
*/
@@ -249,6 +251,15 @@ struct syscore_ops armada_370_xp_timer_syscore_ops = {
.resume = armada_370_xp_timer_resume,
};
+static unsigned long armada_370_delay_timer_read(void)
+{
+ return ~readl(timer_base + TIMER0_VAL_OFF);
+}
+
+static struct delay_timer armada_370_delay_timer = {
+ .read_current_timer = armada_370_delay_timer_read,
+};
+
static void __init armada_370_xp_timer_common_init(struct device_node *np)
{
u32 clr = 0, set = 0;
@@ -287,6 +298,9 @@ static void __init armada_370_xp_timer_common_init(struct device_node *np)
TIMER0_RELOAD_EN | enable_mask,
TIMER0_RELOAD_EN | enable_mask);
+ armada_370_delay_timer.freq = timer_clk;
+ register_current_timer_delay(&armada_370_delay_timer);
+
/*
* Set scale and timer for sched_clock.
*/