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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
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+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