/* * arch/arm/mach-pxa/time.c * * PXA clocksource, clockevents, and OST interrupt handlers. * Copyright (c) 2007 by Bill Gatliff <bgat@billgatliff.com>. * * Derived from Nicolas Pitre's PXA timer handler Copyright (c) 2001 * by MontaVista Software, Inc. (Nico, your code rocks!) * * 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 <linux/kernel.h> #include <linux/init.h> #include <linux/interrupt.h> #include <linux/clockchips.h> #include <asm/div64.h> #include <asm/mach/irq.h> #include <asm/mach/time.h> #include <asm/sched_clock.h> #include <mach/regs-ost.h> #include <mach/irqs.h> /* * This is PXA's sched_clock implementation. This has a resolution * of at least 308 ns and a maximum value of 208 days. * * The return value is guaranteed to be monotonic in that range as * long as there is always less than 582 seconds between successive * calls to sched_clock() which should always be the case in practice. */ static u32 notrace pxa_read_sched_clock(void) { return readl_relaxed(OSCR); } #define MIN_OSCR_DELTA 16 static irqreturn_t pxa_ost0_interrupt(int irq, void *dev_id) { struct clock_event_device *c = dev_id; /* Disarm the compare/match, signal the event. */ writel_relaxed(readl_relaxed(OIER) & ~OIER_E0, OIER); writel_relaxed(OSSR_M0, OSSR); c->event_handler(c); return IRQ_HANDLED; } static int pxa_osmr0_set_next_event(unsigned long delta, struct clock_event_device *dev) { unsigned long next, oscr; writel_relaxed(readl_relaxed(OIER) | OIER_E0, OIER); next = readl_relaxed(OSCR) + delta; writel_relaxed(next, OSMR0); oscr = readl_relaxed(OSCR); return (signed)(next - oscr) <= MIN_OSCR_DELTA ? -ETIME : 0; } static void pxa_osmr0_set_mode(enum clock_event_mode mode, struct clock_event_device *dev) { switch (mode) { case CLOCK_EVT_MODE_ONESHOT: writel_relaxed(readl_relaxed(OIER) & ~OIER_E0, OIER); writel_relaxed(OSSR_M0, OSSR); break; case CLOCK_EVT_MODE_UNUSED: case CLOCK_EVT_MODE_SHUTDOWN: /* initializing, released, or preparing for suspend */ writel_relaxed(readl_relaxed(OIER) & ~OIER_E0, OIER); writel_relaxed(OSSR_M0, OSSR); break; case CLOCK_EVT_MODE_RESUME: case CLOCK_EVT_MODE_PERIODIC: break; } } static struct clock_event_device ckevt_pxa_osmr0 = { .name = "osmr0", .features = CLOCK_EVT_FEAT_ONESHOT, .rating = 200, .set_next_event = pxa_osmr0_set_next_event, .set_mode = pxa_osmr0_set_mode, }; static struct irqaction pxa_ost0_irq = { .name = "ost0", .flags = IRQF_DISABLED | IRQF_TIMER | IRQF_IRQPOLL, .handler = pxa_ost0_interrupt, .dev_id = &ckevt_pxa_osmr0, }; static void __init pxa_timer_init(void) { unsigned long clock_tick_rate = get_clock_tick_rate(); writel_relaxed(0, OIER); writel_relaxed(OSSR_M0 | OSSR_M1 | OSSR_M2 | OSSR_M3, OSSR); setup_sched_clock(pxa_read_sched_clock, 32, clock_tick_rate); clockevents_calc_mult_shift(&ckevt_pxa_osmr0, clock_tick_rate, 4); ckevt_pxa_osmr0.max_delta_ns = clockevent_delta2ns(0x7fffffff, &ckevt_pxa_osmr0); ckevt_pxa_osmr0.min_delta_ns = clockevent_delta2ns(MIN_OSCR_DELTA * 2, &ckevt_pxa_osmr0) + 1; ckevt_pxa_osmr0.cpumask = cpumask_of(0); setup_irq(IRQ_OST0, &pxa_ost0_irq); clocksource_mmio_init(OSCR, "oscr0", clock_tick_rate, 200, 32, clocksource_mmio_readl_up); clockevents_register_device(&ckevt_pxa_osmr0); } #ifdef CONFIG_PM static unsigned long osmr[4], oier, oscr; static void pxa_timer_suspend(void) { osmr[0] = readl_relaxed(OSMR0); osmr[1] = readl_relaxed(OSMR1); osmr[2] = readl_relaxed(OSMR2); osmr[3] = readl_relaxed(OSMR3); oier = readl_relaxed(OIER); oscr = readl_relaxed(OSCR); } static void pxa_timer_resume(void) { /* * Ensure that we have at least MIN_OSCR_DELTA between match * register 0 and the OSCR, to guarantee that we will receive * the one-shot timer interrupt. We adjust OSMR0 in preference * to OSCR to guarantee that OSCR is monotonically incrementing. */ if (osmr[0] - oscr < MIN_OSCR_DELTA) osmr[0] += MIN_OSCR_DELTA; writel_relaxed(osmr[0], OSMR0); writel_relaxed(osmr[1], OSMR1); writel_relaxed(osmr[2], OSMR2); writel_relaxed(osmr[3], OSMR3); writel_relaxed(oier, OIER); writel_relaxed(oscr, OSCR); } #else #define pxa_timer_suspend NULL #define pxa_timer_resume NULL #endif struct sys_timer pxa_timer = { .init = pxa_timer_init, .suspend = pxa_timer_suspend, .resume = pxa_timer_resume, };