From 093617851c5fa0d1fdf5ce378f20691b7adb35e4 Mon Sep 17 00:00:00 2001 From: Colin Cross Date: Sun, 28 Nov 2010 16:26:19 -0800 Subject: [PATCH] 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: Colin Cross --- arch/arm/mach-tegra/timer.c | 60 +++++++++++++++++++++++++++++++++++++++++++-- 1 file changed, 58 insertions(+), 2 deletions(-) diff --git a/arch/arm/mach-tegra/timer.c b/arch/arm/mach-tegra/timer.c index 36b53a7..ffa6a68 100644 --- a/arch/arm/mach-tegra/timer.c +++ b/arch/arm/mach-tegra/timer.c @@ -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 -- 2.7.4