X-Git-Url: http://ftp.safe.ca/?a=blobdiff_plain;f=arch%2Farm%2Fmach-imx%2Ftime.c;h=d86d124aea2290791afabf17cc579a757a6fb19d;hb=e259a3aecbfb61981175ddc7fc02dd180da7d73e;hp=11f1e56c36bc041154e995b00650c0fcb34c4eb0;hpb=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2;p=safe%2Fjmp%2Flinux-2.6 diff --git a/arch/arm/mach-imx/time.c b/arch/arm/mach-imx/time.c index 11f1e56..d86d124 100644 --- a/arch/arm/mach-imx/time.c +++ b/arch/arm/mach-imx/time.c @@ -3,17 +3,20 @@ * * Copyright (C) 2000-2001 Deep Blue Solutions * Copyright (C) 2002 Shane Nay (shane@minirl.com) + * Copyright (C) 2006-2007 Pavel Pisa (ppisa@pikron.com) * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License version 2 as * published by the Free Software Foundation. */ -#include #include #include #include #include +#include #include +#include +#include #include #include @@ -24,70 +27,176 @@ /* Use timer 1 as system timer */ #define TIMER_BASE IMX_TIM1_BASE -/* - * Returns number of us since last clock interrupt. Note that interrupts - * will have been disabled by do_gettimeoffset() - */ -static unsigned long imx_gettimeoffset(void) -{ - unsigned long ticks; - - /* - * Get the current number of ticks. Note that there is a race - * condition between us reading the timer and checking for - * an interrupt. We get around this by ensuring that the - * counter has not reloaded between our two reads. - */ - ticks = IMX_TCN(TIMER_BASE); - - /* - * Interrupt pending? If so, we've reloaded once already. - */ - if (IMX_TSTAT(TIMER_BASE) & TSTAT_COMP) - ticks += LATCH; - - /* - * Convert the ticks to usecs - */ - return (1000000 / CLK32) * ticks; -} +static struct clock_event_device clockevent_imx; +static enum clock_event_mode clockevent_mode = CLOCK_EVT_MODE_UNUSED; /* * IRQ handler for the timer */ static irqreturn_t -imx_timer_interrupt(int irq, void *dev_id, struct pt_regs *regs) +imx_timer_interrupt(int irq, void *dev_id) { - write_seqlock(&xtime_lock); + struct clock_event_device *evt = &clockevent_imx; + uint32_t tstat; + irqreturn_t ret = IRQ_NONE; /* clear the interrupt */ - if (IMX_TSTAT(TIMER_BASE)) - IMX_TSTAT(TIMER_BASE) = 0; + tstat = IMX_TSTAT(TIMER_BASE); + IMX_TSTAT(TIMER_BASE) = 0; - timer_tick(regs); - write_sequnlock(&xtime_lock); + if (tstat & TSTAT_COMP) { + evt->event_handler(evt); + ret = IRQ_HANDLED; + } - return IRQ_HANDLED; + return ret; } static struct irqaction imx_timer_irq = { .name = "i.MX Timer Tick", - .flags = SA_INTERRUPT, - .handler = imx_timer_interrupt + .flags = IRQF_DISABLED | IRQF_TIMER | IRQF_IRQPOLL, + .handler = imx_timer_interrupt, }; /* - * Set up timer interrupt, and return the current time in seconds. + * Set up timer hardware into expected mode and state. */ -static void __init imx_timer_init(void) +static void __init imx_timer_hardware_init(void) { /* * Initialise to a known state (all timers off, and timing reset) */ IMX_TCTL(TIMER_BASE) = 0; IMX_TPRER(TIMER_BASE) = 0; - IMX_TCMP(TIMER_BASE) = LATCH - 1; - IMX_TCTL(TIMER_BASE) = TCTL_CLK_32 | TCTL_IRQEN | TCTL_TEN; + + IMX_TCTL(TIMER_BASE) = TCTL_FRR | TCTL_CLK_PCLK1 | TCTL_TEN; +} + +cycle_t imx_get_cycles(void) +{ + return IMX_TCN(TIMER_BASE); +} + +static struct clocksource clocksource_imx = { + .name = "imx_timer1", + .rating = 200, + .read = imx_get_cycles, + .mask = 0xFFFFFFFF, + .shift = 20, + .flags = CLOCK_SOURCE_IS_CONTINUOUS, +}; + +static int __init imx_clocksource_init(void) +{ + clocksource_imx.mult = + clocksource_hz2mult(imx_get_perclk1(), clocksource_imx.shift); + clocksource_register(&clocksource_imx); + + return 0; +} + +static int imx_set_next_event(unsigned long evt, + struct clock_event_device *unused) +{ + unsigned long tcmp; + + tcmp = IMX_TCN(TIMER_BASE) + evt; + IMX_TCMP(TIMER_BASE) = tcmp; + + return (int32_t)(tcmp - IMX_TCN(TIMER_BASE)) < 0 ? -ETIME : 0; +} + +#ifdef DEBUG +static const char *clock_event_mode_label[]={ + [CLOCK_EVT_MODE_PERIODIC] = "CLOCK_EVT_MODE_PERIODIC", + [CLOCK_EVT_MODE_ONESHOT] = "CLOCK_EVT_MODE_ONESHOT", + [CLOCK_EVT_MODE_SHUTDOWN] = "CLOCK_EVT_MODE_SHUTDOWN", + [CLOCK_EVT_MODE_UNUSED] = "CLOCK_EVT_MODE_UNUSED" +}; +#endif /*DEBUG*/ + +static void imx_set_mode(enum clock_event_mode mode, struct clock_event_device *evt) +{ + unsigned long flags; + + /* + * The timer interrupt generation is disabled at least + * for enough time to call imx_set_next_event() + */ + local_irq_save(flags); + /* Disable interrupt in GPT module */ + IMX_TCTL(TIMER_BASE) &= ~TCTL_IRQEN; + if (mode != clockevent_mode) { + /* Set event time into far-far future */ + IMX_TCMP(TIMER_BASE) = IMX_TCN(TIMER_BASE) - 3; + /* Clear pending interrupt */ + IMX_TSTAT(TIMER_BASE) &= ~TSTAT_COMP; + } + +#ifdef DEBUG + printk(KERN_INFO "imx_set_mode: changing mode from %s to %s\n", + clock_event_mode_label[clockevent_mode], clock_event_mode_label[mode]); +#endif /*DEBUG*/ + + /* Remember timer mode */ + clockevent_mode = mode; + local_irq_restore(flags); + + switch (mode) { + case CLOCK_EVT_MODE_PERIODIC: + printk(KERN_ERR "imx_set_mode: Periodic mode is not supported for i.MX\n"); + break; + case CLOCK_EVT_MODE_ONESHOT: + /* + * Do not put overhead of interrupt enable/disable into + * imx_set_next_event(), the core has about 4 minutes + * to call imx_set_next_event() or shutdown clock after + * mode switching + */ + local_irq_save(flags); + IMX_TCTL(TIMER_BASE) |= TCTL_IRQEN; + local_irq_restore(flags); + break; + case CLOCK_EVT_MODE_SHUTDOWN: + case CLOCK_EVT_MODE_UNUSED: + case CLOCK_EVT_MODE_RESUME: + /* Left event sources disabled, no more interrupts appears */ + break; + } +} + +static struct clock_event_device clockevent_imx = { + .name = "imx_timer1", + .features = CLOCK_EVT_FEAT_ONESHOT, + .shift = 32, + .set_mode = imx_set_mode, + .set_next_event = imx_set_next_event, + .rating = 200, +}; + +static int __init imx_clockevent_init(void) +{ + clockevent_imx.mult = div_sc(imx_get_perclk1(), NSEC_PER_SEC, + clockevent_imx.shift); + clockevent_imx.max_delta_ns = + clockevent_delta2ns(0xfffffffe, &clockevent_imx); + clockevent_imx.min_delta_ns = + clockevent_delta2ns(0xf, &clockevent_imx); + + clockevent_imx.cpumask = cpumask_of_cpu(0); + + clockevents_register_device(&clockevent_imx); + + return 0; +} + + +static void __init imx_timer_init(void) +{ + imx_timer_hardware_init(); + imx_clocksource_init(); + + imx_clockevent_init(); /* * Make irqs happen for the system timer @@ -97,5 +206,4 @@ static void __init imx_timer_init(void) struct sys_timer imx_timer = { .init = imx_timer_init, - .offset = imx_gettimeoffset, };