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Commit cb0f2538 authored by Russell King's avatar Russell King Committed by Daniel Lezcano
Browse files

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: default avatarRussell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: default avatarDaniel Lezcano <daniel.lezcano@linaro.org>
Tested-by: default avatarGregory CLEMENT <gregory.clement@free-electrons.com>
Acked-by: default avatarGregory CLEMENT <gregory.clement@free-electrons.com>
parent ccd63ce4

drivers/clocksource/time-armada-370-xp.c

+14 −0
Original line number Diff line number Diff line
@@ -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.

	 */