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Commit 09361785 authored by Colin Cross's avatar Colin Cross
Browse files

ARM: tegra: timer: Add idle and suspend support to timers 



Implement read_persistent_clock by reading the Tegra RTC
registers that stay running during suspend.

Save and restore the timer configuration register in
suspend.

Signed-off-by: default avatarColin Cross <ccross@android.com>
parent 3c3895b4

arch/arm/mach-tegra/timer.c

+58 −2
Original line number Diff line number Diff line
@@ -38,6 +38,10 @@ 
#include "board.h"

#include "clock.h"



#define RTC_SECONDS            0x08

#define RTC_SHADOW_SECONDS     0x0c

#define RTC_MILLISECONDS       0x10



#define TIMERUS_CNTR_1US 0x10

#define TIMERUS_USEC_CFG 0x14

#define TIMERUS_CNTR_FREEZE 0x4c
@@ -50,9 +54,11 @@ 
#define TIMER_PTV 0x0

#define TIMER_PCR 0x4



struct tegra_timer;



static void __iomem *timer_reg_base = IO_ADDRESS(TEGRA_TMR1_BASE);

static void __iomem *rtc_base = IO_ADDRESS(TEGRA_RTC_BASE);



static struct timespec persistent_ts;

static u64 persistent_ms, last_persistent_ms;



#define timer_writel(value, reg) \

	__raw_writel(value, (u32)timer_reg_base + (reg))
@@ -133,6 +139,42 @@ static void notrace tegra_update_sched_clock(void) 
	update_sched_clock(&cd, cyc, (u32)~0);

}



/*

 * tegra_rtc_read - Reads the Tegra RTC registers

 * Care must be taken that this funciton is not called while the

 * tegra_rtc driver could be executing to avoid race conditions

 * on the RTC shadow register

 */

u64 tegra_rtc_read_ms(void)

{

	u32 ms = readl(rtc_base + RTC_MILLISECONDS);

	u32 s = readl(rtc_base + RTC_SHADOW_SECONDS);

	return (u64)s * MSEC_PER_SEC + ms;

}



/*

 * read_persistent_clock -  Return time from a persistent clock.

 *

 * Reads the time from a source which isn't disabled during PM, the

 * 32k sync timer.  Convert the cycles elapsed since last read into

 * nsecs and adds to a monotonically increasing timespec.

 * Care must be taken that this funciton is not called while the

 * tegra_rtc driver could be executing to avoid race conditions

 * on the RTC shadow register

 */

void read_persistent_clock(struct timespec *ts)

{

	u64 delta;

	struct timespec *tsp = &persistent_ts;



	last_persistent_ms = persistent_ms;

	persistent_ms = tegra_rtc_read_ms();

	delta = persistent_ms - last_persistent_ms;



	timespec_add_ns(tsp, delta * NSEC_PER_MSEC);

	*ts = *tsp;

}



static irqreturn_t tegra_timer_interrupt(int irq, void *dev_id)

{

	struct clock_event_device *evt = (struct clock_event_device *)dev_id;
@@ -204,3 +246,17 @@ static void __init tegra_init_timer(void) 
struct sys_timer tegra_timer = {

	.init = tegra_init_timer,

};



#ifdef CONFIG_PM

static u32 usec_config;



void tegra_timer_suspend(void)

{

	usec_config = timer_readl(TIMERUS_USEC_CFG);

}



void tegra_timer_resume(void)

{

	timer_writel(usec_config, TIMERUS_USEC_CFG);

}

#endif