diff options
Diffstat (limited to 'arch/arm/plat-omap')
| -rw-r--r-- | arch/arm/plat-omap/Kconfig | 1 | ||||
| -rw-r--r-- | arch/arm/plat-omap/common.c | 50 | ||||
| -rw-r--r-- | arch/arm/plat-omap/timer32k.c | 139 |
3 files changed, 90 insertions, 100 deletions
diff --git a/arch/arm/plat-omap/Kconfig b/arch/arm/plat-omap/Kconfig index a347fb5946c..cfc69f3842f 100644 --- a/arch/arm/plat-omap/Kconfig +++ b/arch/arm/plat-omap/Kconfig @@ -11,6 +11,7 @@ choice config ARCH_OMAP1 bool "TI OMAP1" + select GENERIC_CLOCKEVENTS config ARCH_OMAP2 bool "TI OMAP2" diff --git a/arch/arm/plat-omap/common.c b/arch/arm/plat-omap/common.c index ffb94aa164a..dd8708ad0a7 100644 --- a/arch/arm/plat-omap/common.c +++ b/arch/arm/plat-omap/common.c @@ -160,3 +160,53 @@ static int __init omap_add_serial_console(void) return add_preferred_console("ttyS", line, opt); } console_initcall(omap_add_serial_console); + + +/* + * 32KHz clocksource ... always available, on pretty most chips except + * OMAP 730 and 1510. Other timers could be used as clocksources, with + * higher resolution in free-running counter modes (e.g. 12 MHz xtal), + * but systems won't necessarily want to spend resources that way. + */ + +#if defined(CONFIG_ARCH_OMAP16XX) +#define TIMER_32K_SYNCHRONIZED 0xfffbc410 +#elif defined(CONFIG_ARCH_OMAP24XX) +#define TIMER_32K_SYNCHRONIZED 0x48004010 +#endif + +#ifdef TIMER_32K_SYNCHRONIZED + +#include <linux/clocksource.h> + +static cycle_t omap_32k_read(void) +{ + return omap_readl(TIMER_32K_SYNCHRONIZED); +} + +static struct clocksource clocksource_32k = { + .name = "32k_counter", + .rating = 250, + .read = omap_32k_read, + .mask = CLOCKSOURCE_MASK(32), + .shift = 10, + .flags = CLOCK_SOURCE_IS_CONTINUOUS, +}; + +static int __init omap_init_clocksource_32k(void) +{ + static char err[] __initdata = KERN_ERR + "%s: can't register clocksource!\n"; + + if (cpu_is_omap16xx() || cpu_is_omap24xx()) { + clocksource_32k.mult = clocksource_hz2mult(32768, + clocksource_32k.shift); + + if (clocksource_register(&clocksource_32k)) + printk(err, clocksource_32k.name); + } + return 0; +} +arch_initcall(omap_init_clocksource_32k); + +#endif /* TIMER_32K_SYNCHRONIZED */ diff --git a/arch/arm/plat-omap/timer32k.c b/arch/arm/plat-omap/timer32k.c index 26531060116..114f87151d6 100644 --- a/arch/arm/plat-omap/timer32k.c +++ b/arch/arm/plat-omap/timer32k.c @@ -42,6 +42,8 @@ #include <linux/spinlock.h> #include <linux/err.h> #include <linux/clk.h> +#include <linux/clocksource.h> +#include <linux/clockchips.h> #include <asm/system.h> #include <asm/hardware.h> @@ -80,13 +82,13 @@ struct sys_timer omap_timer; #define OMAP1_32K_TIMER_TVR 0x00 #define OMAP1_32K_TIMER_TCR 0x04 -#define OMAP_32K_TICKS_PER_HZ (32768 / HZ) +#define OMAP_32K_TICKS_PER_SEC (32768) /* * TRM says 1 / HZ = ( TVR + 1) / 32768, so TRV = (32768 / HZ) - 1 * so with HZ = 128, TVR = 255. */ -#define OMAP_32K_TIMER_TICK_PERIOD ((32768 / HZ) - 1) +#define OMAP_32K_TIMER_TICK_PERIOD ((OMAP_32K_TICKS_PER_SEC / HZ) - 1) #define JIFFIES_TO_HW_TICKS(nr_jiffies, clock_rate) \ (((nr_jiffies) * (clock_rate)) / HZ) @@ -142,6 +144,28 @@ static inline void omap_32k_timer_ack_irq(void) #endif +static void omap_32k_timer_set_mode(enum clock_event_mode mode, + struct clock_event_device *evt) +{ + switch (mode) { + case CLOCK_EVT_MODE_ONESHOT: + case CLOCK_EVT_MODE_PERIODIC: + omap_32k_timer_start(OMAP_32K_TIMER_TICK_PERIOD); + break; + case CLOCK_EVT_MODE_UNUSED: + case CLOCK_EVT_MODE_SHUTDOWN: + omap_32k_timer_stop(); + break; + } +} + +static struct clock_event_device clockevent_32k_timer = { + .name = "32k-timer", + .features = CLOCK_EVT_FEAT_PERIODIC, + .shift = 32, + .set_mode = omap_32k_timer_set_mode, +}; + /* * The 32KHz synchronized timer is an additional timer on 16xx. * It is always running. @@ -171,15 +195,6 @@ omap_32k_ticks_to_nsecs(unsigned long ticks_32k) 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. */ @@ -188,95 +203,16 @@ 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 inline irqreturn_t _omap_32k_timer_interrupt(int irq, void *dev_id) -{ - unsigned long now; - - omap_32k_timer_ack_irq(); - now = omap_32k_sync_timer_read(); - - while ((signed long)(now - omap_32k_last_tick) - >= OMAP_32K_TICKS_PER_HZ) { - omap_32k_last_tick += OMAP_32K_TICKS_PER_HZ; - timer_tick(); - } - - /* 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); - - return IRQ_HANDLED; -} - -static irqreturn_t omap_32k_timer_handler(int irq, void *dev_id) -{ - return _omap_32k_timer_interrupt(irq, dev_id); -} - static irqreturn_t omap_32k_timer_interrupt(int irq, void *dev_id) { - unsigned long flags; + struct clock_event_device *evt = &clockevent_32k_timer; + omap_32k_timer_ack_irq(); - write_seqlock_irqsave(&xtime_lock, flags); - _omap_32k_timer_interrupt(irq, dev_id); - write_sequnlock_irqrestore(&xtime_lock, flags); + evt->event_handler(evt); 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) -{ - unsigned long ticks = JIFFIES_TO_HW_TICKS(next_tick, 32768) + 1; - unsigned long now = omap_32k_sync_timer_read(); - unsigned long idled = now - omap_32k_last_tick; - - if (idled + 1 < ticks) - ticks -= idled; - else - ticks = 1; - omap_32k_timer_start(ticks); -} - -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_handler, -}; -#endif /* CONFIG_NO_IDLE_HZ */ - static struct irqaction omap_32k_timer_irq = { .name = "32KHz timer", .flags = IRQF_DISABLED | IRQF_TIMER, @@ -285,13 +221,8 @@ static struct irqaction omap_32k_timer_irq = { static __init void omap_init_32k_timer(void) { -#ifdef CONFIG_NO_IDLE_HZ - omap_timer.dyn_tick = &omap_dyn_tick_timer; -#endif - if (cpu_class_is_omap1()) 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(); #ifdef CONFIG_ARCH_OMAP2 @@ -308,7 +239,16 @@ static __init void omap_init_32k_timer(void) } #endif - omap_32k_timer_start(OMAP_32K_TIMER_TICK_PERIOD); + clockevent_32k_timer.mult = div_sc(OMAP_32K_TICKS_PER_SEC, + NSEC_PER_SEC, + clockevent_32k_timer.shift); + clockevent_32k_timer.max_delta_ns = + clockevent_delta2ns(0xfffffffe, &clockevent_32k_timer); + clockevent_32k_timer.min_delta_ns = + clockevent_delta2ns(1, &clockevent_32k_timer); + + clockevent_32k_timer.cpumask = cpumask_of_cpu(0); + clockevents_register_device(&clockevent_32k_timer); } /* @@ -326,5 +266,4 @@ static void __init omap_timer_init(void) struct sys_timer omap_timer = { .init = omap_timer_init, - .offset = NULL, /* Initialized later */ }; |