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

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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: Colin Cross <ccross@android.com>
This commit is contained in:
Colin Cross 2010-11-28 16:26:19 -08:00
parent 3c3895b4bf
commit 093617851c
1 changed files with 58 additions and 2 deletions
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60
arch/arm/mach-tegra/timer.c
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@ -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