X-Git-Url: http://git.onelab.eu/?a=blobdiff_plain;f=arch%2Farm%2Fmach-omap1%2Ftime.c;h=cdbf4d7620c6ce49df6f813d8f398c96fd084862;hb=987b0145d94eecf292d8b301228356f44611ab7c;hp=a85fe6066bc47d9a3e6168ff1686b6356dcec200;hpb=f7ed79d23a47594e7834d66a8f14449796d4f3e6;p=linux-2.6.git diff --git a/arch/arm/mach-omap1/time.c b/arch/arm/mach-omap1/time.c index a85fe6066..cdbf4d762 100644 --- a/arch/arm/mach-omap1/time.c +++ b/arch/arm/mach-omap1/time.c @@ -51,6 +51,8 @@ struct sys_timer omap_timer; +#ifdef CONFIG_OMAP_MPU_TIMER + /* * --------------------------------------------------------------------------- * MPU timer @@ -220,6 +222,195 @@ unsigned long long sched_clock(void) return cycles_2_ns(ticks64); } +#endif /* CONFIG_OMAP_MPU_TIMER */ + +#ifdef CONFIG_OMAP_32K_TIMER + +#ifdef CONFIG_ARCH_OMAP15XX +#error OMAP 32KHz timer does not currently work on 15XX! +#endif + +/* + * --------------------------------------------------------------------------- + * 32KHz OS timer + * + * This currently works only on 16xx, as 1510 does not have the continuous + * 32KHz synchronous timer. The 32KHz synchronous timer is used to keep track + * of time in addition to the 32KHz OS timer. Using only the 32KHz OS timer + * on 1510 would be possible, but the timer would not be as accurate as + * with the 32KHz synchronized timer. + * --------------------------------------------------------------------------- + */ +#define OMAP_32K_TIMER_BASE 0xfffb9000 +#define OMAP_32K_TIMER_CR 0x08 +#define OMAP_32K_TIMER_TVR 0x00 +#define OMAP_32K_TIMER_TCR 0x04 + +#define OMAP_32K_TICKS_PER_HZ (32768 / HZ) + +/* + * TRM says 1 / HZ = ( TVR + 1) / 32768, so TRV = (32768 / HZ) - 1 + * so with HZ = 100, TVR = 327.68. + */ +#define OMAP_32K_TIMER_TICK_PERIOD ((32768 / HZ) - 1) +#define TIMER_32K_SYNCHRONIZED 0xfffbc410 + +#define JIFFIES_TO_HW_TICKS(nr_jiffies, clock_rate) \ + (((nr_jiffies) * (clock_rate)) / HZ) + +static inline void omap_32k_timer_write(int val, int reg) +{ + omap_writew(val, reg + OMAP_32K_TIMER_BASE); +} + +static inline unsigned long omap_32k_timer_read(int reg) +{ + return omap_readl(reg + OMAP_32K_TIMER_BASE) & 0xffffff; +} + +/* + * The 32KHz synchronized timer is an additional timer on 16xx. + * It is always running. + */ +static inline unsigned long omap_32k_sync_timer_read(void) +{ + return omap_readl(TIMER_32K_SYNCHRONIZED); +} + +static inline void omap_32k_timer_start(unsigned long load_val) +{ + omap_32k_timer_write(load_val, OMAP_32K_TIMER_TVR); + omap_32k_timer_write(0x0f, OMAP_32K_TIMER_CR); +} + +static inline void omap_32k_timer_stop(void) +{ + omap_32k_timer_write(0x0, OMAP_32K_TIMER_CR); +} + +/* + * Rounds down to nearest usec. Note that this will overflow for larger values. + */ +static inline unsigned long omap_32k_ticks_to_usecs(unsigned long ticks_32k) +{ + return (ticks_32k * 5*5*5*5*5*5) >> 9; +} + +/* + * Rounds down to nearest nsec. + */ +static inline unsigned long long +omap_32k_ticks_to_nsecs(unsigned long ticks_32k) +{ + return (unsigned long long) ticks_32k * 1000 * 5*5*5*5*5*5 >> 9; +} + +static unsigned long omap_32k_last_tick = 0; + +/* + * Returns elapsed usecs since last 32k timer interrupt + */ +static unsigned long omap_32k_timer_gettimeoffset(void) +{ + unsigned long now = omap_32k_sync_timer_read(); + return omap_32k_ticks_to_usecs(now - omap_32k_last_tick); +} + +/* + * Returns current time from boot in nsecs. It's OK for this to wrap + * around for now, as it's just a relative time stamp. + */ +unsigned long long sched_clock(void) +{ + return omap_32k_ticks_to_nsecs(omap_32k_sync_timer_read()); +} + +/* + * Timer interrupt for 32KHz timer. When dynamic tick is enabled, this + * function is also called from other interrupts to remove latency + * issues with dynamic tick. In the dynamic tick case, we need to lock + * with irqsave. + */ +static irqreturn_t omap_32k_timer_interrupt(int irq, void *dev_id, + struct pt_regs *regs) +{ + unsigned long flags; + unsigned long now; + + write_seqlock_irqsave(&xtime_lock, flags); + now = omap_32k_sync_timer_read(); + + while (now - omap_32k_last_tick >= OMAP_32K_TICKS_PER_HZ) { + omap_32k_last_tick += OMAP_32K_TICKS_PER_HZ; + timer_tick(regs); + } + + /* Restart timer so we don't drift off due to modulo or dynamic tick. + * By default we program the next timer to be continuous to avoid + * latencies during high system load. During dynamic tick operation the + * continuous timer can be overridden from pm_idle to be longer. + */ + omap_32k_timer_start(omap_32k_last_tick + OMAP_32K_TICKS_PER_HZ - now); + write_sequnlock_irqrestore(&xtime_lock, flags); + + return IRQ_HANDLED; +} + +#ifdef CONFIG_NO_IDLE_HZ +/* + * Programs the next timer interrupt needed. Called when dynamic tick is + * enabled, and to reprogram the ticks to skip from pm_idle. Note that + * we can keep the timer continuous, and don't need to set it to run in + * one-shot mode. This is because the timer will get reprogrammed again + * after next interrupt. + */ +void omap_32k_timer_reprogram(unsigned long next_tick) +{ + omap_32k_timer_start(JIFFIES_TO_HW_TICKS(next_tick, 32768) + 1); +} + +static struct irqaction omap_32k_timer_irq; +extern struct timer_update_handler timer_update; + +static int omap_32k_timer_enable_dyn_tick(void) +{ + /* No need to reprogram timer, just use the next interrupt */ + return 0; +} + +static int omap_32k_timer_disable_dyn_tick(void) +{ + omap_32k_timer_start(OMAP_32K_TIMER_TICK_PERIOD); + return 0; +} + +static struct dyn_tick_timer omap_dyn_tick_timer = { + .enable = omap_32k_timer_enable_dyn_tick, + .disable = omap_32k_timer_disable_dyn_tick, + .reprogram = omap_32k_timer_reprogram, + .handler = omap_32k_timer_interrupt, +}; +#endif /* CONFIG_NO_IDLE_HZ */ + +static struct irqaction omap_32k_timer_irq = { + .name = "32KHz timer", + .flags = SA_INTERRUPT | SA_TIMER, + .handler = omap_32k_timer_interrupt, +}; + +static __init void omap_init_32k_timer(void) +{ + +#ifdef CONFIG_NO_IDLE_HZ + omap_timer.dyn_tick = &omap_dyn_tick_timer; +#endif + + setup_irq(INT_OS_TIMER, &omap_32k_timer_irq); + omap_timer.offset = omap_32k_timer_gettimeoffset; + omap_32k_last_tick = omap_32k_sync_timer_read(); + omap_32k_timer_start(OMAP_32K_TIMER_TICK_PERIOD); +} +#endif /* CONFIG_OMAP_32K_TIMER */ /* * --------------------------------------------------------------------------- @@ -228,7 +419,13 @@ unsigned long long sched_clock(void) */ static void __init omap_timer_init(void) { +#if defined(CONFIG_OMAP_MPU_TIMER) omap_init_mpu_timer(); +#elif defined(CONFIG_OMAP_32K_TIMER) + omap_init_32k_timer(); +#else +#error No system timer selected in Kconfig! +#endif } struct sys_timer omap_timer = {