diff options
author | Kevin Hilman <khilman@mvista.com> | 2007-03-08 20:32:19 +0100 |
---|---|---|
committer | Russell King <rmk+kernel@arm.linux.org.uk> | 2007-04-21 21:02:55 +0100 |
commit | 075192ae807579448afcc0833bd349ccce057825 (patch) | |
tree | 5627ae9d65bc8791793fde1bc2ad8f62bc015e44 /arch/arm/mach-omap1/time.c | |
parent | 89df127246f23add865f4a8f719c990e41151843 (diff) | |
download | linux-075192ae807579448afcc0833bd349ccce057825.tar.bz2 |
[ARM] 4262/1: OMAP: clocksource and clockevent support
Update OMAP1 to enable support for hrtimers and dynticks by using new clocksource and clockevent infrastructure.
Signed-off-by: Kevin Hilman <khilman@mvista.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Diffstat (limited to 'arch/arm/mach-omap1/time.c')
-rw-r--r-- | arch/arm/mach-omap1/time.c | 206 |
1 files changed, 133 insertions, 73 deletions
diff --git a/arch/arm/mach-omap1/time.c b/arch/arm/mach-omap1/time.c index 1b7e4a506c26..85e048b259f5 100644 --- a/arch/arm/mach-omap1/time.c +++ b/arch/arm/mach-omap1/time.c @@ -39,6 +39,10 @@ #include <linux/interrupt.h> #include <linux/sched.h> #include <linux/spinlock.h> +#include <linux/clk.h> +#include <linux/err.h> +#include <linux/clocksource.h> +#include <linux/clockchips.h> #include <asm/system.h> #include <asm/hardware.h> @@ -48,13 +52,7 @@ #include <asm/mach/irq.h> #include <asm/mach/time.h> -struct sys_timer omap_timer; -/* - * --------------------------------------------------------------------------- - * MPU timer - * --------------------------------------------------------------------------- - */ #define OMAP_MPU_TIMER_BASE OMAP_MPU_TIMER1_BASE #define OMAP_MPU_TIMER_OFFSET 0x100 @@ -88,21 +86,6 @@ static inline unsigned long long cycles_2_ns(unsigned long long cyc) return (cyc * cyc2ns_scale) >> CYC2NS_SCALE_FACTOR; } -/* - * MPU_TICKS_PER_SEC must be an even number, otherwise machinecycles_to_usecs - * will break. On P2, the timer count rate is 6.5 MHz after programming PTV - * with 0. This divides the 13MHz input by 2, and is undocumented. - */ -#if defined(CONFIG_MACH_OMAP_PERSEUS2) || defined(CONFIG_MACH_OMAP_FSAMPLE) -/* REVISIT: This ifdef construct should be replaced by a query to clock - * framework to see if timer base frequency is 12.0, 13.0 or 19.2 MHz. - */ -#define MPU_TICKS_PER_SEC (13000000 / 2) -#else -#define MPU_TICKS_PER_SEC (12000000 / 2) -#endif - -#define MPU_TIMER_TICK_PERIOD ((MPU_TICKS_PER_SEC / HZ) - 1) typedef struct { u32 cntl; /* CNTL_TIMER, R/W */ @@ -120,98 +103,164 @@ static inline unsigned long omap_mpu_timer_read(int nr) return timer->read_tim; } -static inline void omap_mpu_timer_start(int nr, unsigned long load_val) +static inline void omap_mpu_set_autoreset(int nr) { volatile omap_mpu_timer_regs_t* timer = omap_mpu_timer_base(nr); - timer->cntl = MPU_TIMER_CLOCK_ENABLE; - udelay(1); - timer->load_tim = load_val; - udelay(1); - timer->cntl = (MPU_TIMER_CLOCK_ENABLE | MPU_TIMER_AR | MPU_TIMER_ST); + timer->cntl = timer->cntl | MPU_TIMER_AR; } -unsigned long omap_mpu_timer_ticks_to_usecs(unsigned long nr_ticks) +static inline void omap_mpu_remove_autoreset(int nr) { - unsigned long long nsec; + volatile omap_mpu_timer_regs_t* timer = omap_mpu_timer_base(nr); - nsec = cycles_2_ns((unsigned long long)nr_ticks); - return (unsigned long)nsec / 1000; + timer->cntl = timer->cntl & ~MPU_TIMER_AR; } -/* - * Last processed system timer interrupt - */ -static unsigned long omap_mpu_timer_last = 0; +static inline void omap_mpu_timer_start(int nr, unsigned long load_val, + int autoreset) +{ + volatile omap_mpu_timer_regs_t* timer = omap_mpu_timer_base(nr); + unsigned int timerflags = (MPU_TIMER_CLOCK_ENABLE | MPU_TIMER_ST); + + if (autoreset) timerflags |= MPU_TIMER_AR; + + timer->cntl = MPU_TIMER_CLOCK_ENABLE; + udelay(1); + timer->load_tim = load_val; + udelay(1); + timer->cntl = timerflags; +} /* - * Returns elapsed usecs since last system timer interrupt + * --------------------------------------------------------------------------- + * MPU timer 1 ... count down to zero, interrupt, reload + * --------------------------------------------------------------------------- */ -static unsigned long omap_mpu_timer_gettimeoffset(void) +static int omap_mpu_set_next_event(unsigned long cycles, + struct clock_event_device *evt) { - unsigned long now = 0 - omap_mpu_timer_read(0); - unsigned long elapsed = now - omap_mpu_timer_last; + omap_mpu_timer_start(0, cycles, 0); + return 0; +} - return omap_mpu_timer_ticks_to_usecs(elapsed); +static void omap_mpu_set_mode(enum clock_event_mode mode, + struct clock_event_device *evt) +{ + switch (mode) { + case CLOCK_EVT_MODE_PERIODIC: + omap_mpu_set_autoreset(0); + break; + case CLOCK_EVT_MODE_ONESHOT: + omap_mpu_remove_autoreset(0); + break; + case CLOCK_EVT_MODE_UNUSED: + case CLOCK_EVT_MODE_SHUTDOWN: + break; + } } -/* - * Elapsed time between interrupts is calculated using timer0. - * Latency during the interrupt is calculated using timer1. - * Both timer0 and timer1 are counting at 6MHz (P2 6.5MHz). - */ -static irqreturn_t omap_mpu_timer_interrupt(int irq, void *dev_id) +static struct clock_event_device clockevent_mpu_timer1 = { + .name = "mpu_timer1", + .features = CLOCK_EVT_FEAT_PERIODIC, CLOCK_EVT_FEAT_ONESHOT, + .shift = 32, + .set_next_event = omap_mpu_set_next_event, + .set_mode = omap_mpu_set_mode, +}; + +static irqreturn_t omap_mpu_timer1_interrupt(int irq, void *dev_id) { - unsigned long now, latency; + struct clock_event_device *evt = &clockevent_mpu_timer1; - write_seqlock(&xtime_lock); - now = 0 - omap_mpu_timer_read(0); - latency = MPU_TICKS_PER_SEC / HZ - omap_mpu_timer_read(1); - omap_mpu_timer_last = now - latency; - timer_tick(); - write_sequnlock(&xtime_lock); + evt->event_handler(evt); return IRQ_HANDLED; } -static struct irqaction omap_mpu_timer_irq = { - .name = "mpu timer", +static struct irqaction omap_mpu_timer1_irq = { + .name = "mpu_timer1", .flags = IRQF_DISABLED | IRQF_TIMER, - .handler = omap_mpu_timer_interrupt, + .handler = omap_mpu_timer1_interrupt, }; -static unsigned long omap_mpu_timer1_overflows; -static irqreturn_t omap_mpu_timer1_interrupt(int irq, void *dev_id) +static __init void omap_init_mpu_timer(unsigned long rate) +{ + set_cyc2ns_scale(rate / 1000); + + setup_irq(INT_TIMER1, &omap_mpu_timer1_irq); + omap_mpu_timer_start(0, (rate / HZ) - 1, 1); + + clockevent_mpu_timer1.mult = div_sc(rate, NSEC_PER_SEC, + clockevent_mpu_timer1.shift); + clockevent_mpu_timer1.max_delta_ns = + clockevent_delta2ns(-1, &clockevent_mpu_timer1); + clockevent_mpu_timer1.min_delta_ns = + clockevent_delta2ns(1, &clockevent_mpu_timer1); + + clockevent_mpu_timer1.cpumask = cpumask_of_cpu(0); + clockevents_register_device(&clockevent_mpu_timer1); +} + + +/* + * --------------------------------------------------------------------------- + * MPU timer 2 ... free running 32-bit clock source and scheduler clock + * --------------------------------------------------------------------------- + */ + +static unsigned long omap_mpu_timer2_overflows; + +static irqreturn_t omap_mpu_timer2_interrupt(int irq, void *dev_id) { - omap_mpu_timer1_overflows++; + omap_mpu_timer2_overflows++; return IRQ_HANDLED; } -static struct irqaction omap_mpu_timer1_irq = { - .name = "mpu timer1 overflow", +static struct irqaction omap_mpu_timer2_irq = { + .name = "mpu_timer2", .flags = IRQF_DISABLED, - .handler = omap_mpu_timer1_interrupt, + .handler = omap_mpu_timer2_interrupt, }; -static __init void omap_init_mpu_timer(void) +static cycle_t mpu_read(void) { - set_cyc2ns_scale(MPU_TICKS_PER_SEC / 1000); - omap_timer.offset = omap_mpu_timer_gettimeoffset; - setup_irq(INT_TIMER1, &omap_mpu_timer1_irq); - setup_irq(INT_TIMER2, &omap_mpu_timer_irq); - omap_mpu_timer_start(0, 0xffffffff); - omap_mpu_timer_start(1, MPU_TIMER_TICK_PERIOD); + return ~omap_mpu_timer_read(1); +} + +static struct clocksource clocksource_mpu = { + .name = "mpu_timer2", + .rating = 300, + .read = mpu_read, + .mask = CLOCKSOURCE_MASK(32), + .shift = 24, + .flags = CLOCK_SOURCE_IS_CONTINUOUS, +}; + +static void __init omap_init_clocksource(unsigned long rate) +{ + static char err[] __initdata = KERN_ERR + "%s: can't register clocksource!\n"; + + clocksource_mpu.mult + = clocksource_khz2mult(rate/1000, clocksource_mpu.shift); + + setup_irq(INT_TIMER2, &omap_mpu_timer2_irq); + omap_mpu_timer_start(1, ~0, 1); + + if (clocksource_register(&clocksource_mpu)) + printk(err, clocksource_mpu.name); } + /* * Scheduler clock - returns current time in nanosec units. */ unsigned long long sched_clock(void) { - unsigned long ticks = 0 - omap_mpu_timer_read(0); + unsigned long ticks = 0 - omap_mpu_timer_read(1); unsigned long long ticks64; - ticks64 = omap_mpu_timer1_overflows; + ticks64 = omap_mpu_timer2_overflows; ticks64 <<= 32; ticks64 |= ticks; @@ -225,10 +274,21 @@ unsigned long long sched_clock(void) */ static void __init omap_timer_init(void) { - omap_init_mpu_timer(); + struct clk *ck_ref = clk_get(NULL, "ck_ref"); + unsigned long rate; + + BUG_ON(IS_ERR(ck_ref)); + + rate = clk_get_rate(ck_ref); + clk_put(ck_ref); + + /* PTV = 0 */ + rate /= 2; + + omap_init_mpu_timer(rate); + omap_init_clocksource(rate); } struct sys_timer omap_timer = { .init = omap_timer_init, - .offset = NULL, /* Initialized later */ }; |