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Diffstat (limited to 'arch/arm/mach-mmp/time.c')
| -rw-r--r-- | arch/arm/mach-mmp/time.c | 199 |
1 files changed, 199 insertions, 0 deletions
diff --git a/arch/arm/mach-mmp/time.c b/arch/arm/mach-mmp/time.c new file mode 100644 index 000000000000..b03a6eda7419 --- /dev/null +++ b/arch/arm/mach-mmp/time.c @@ -0,0 +1,199 @@ +/* + * linux/arch/arm/mach-mmp/time.c + * + * Support for clocksource and clockevents + * + * Copyright (C) 2008 Marvell International Ltd. + * All rights reserved. + * + * 2008-04-11: Jason Chagas <Jason.chagas@marvell.com> + * 2008-10-08: Bin Yang <bin.yang@marvell.com> + * + * The timers module actually includes three timers, each timer with upto + * three match comparators. Timer #0 is used here in free-running mode as + * the clock source, and match comparator #1 used as clock event device. + * + * 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/init.h> +#include <linux/kernel.h> +#include <linux/interrupt.h> +#include <linux/clockchips.h> + +#include <linux/io.h> +#include <linux/irq.h> +#include <linux/sched.h> +#include <linux/cnt32_to_63.h> + +#include <mach/addr-map.h> +#include <mach/regs-timers.h> +#include <mach/irqs.h> + +#include "clock.h" + +#define TIMERS_VIRT_BASE TIMERS1_VIRT_BASE + +#define MAX_DELTA (0xfffffffe) +#define MIN_DELTA (16) + +#define TCR2NS_SCALE_FACTOR 10 + +static unsigned long tcr2ns_scale; + +static void __init set_tcr2ns_scale(unsigned long tcr_rate) +{ + unsigned long long v = 1000000000ULL << TCR2NS_SCALE_FACTOR; + do_div(v, tcr_rate); + tcr2ns_scale = v; + /* + * We want an even value to automatically clear the top bit + * returned by cnt32_to_63() without an additional run time + * instruction. So if the LSB is 1 then round it up. + */ + if (tcr2ns_scale & 1) + tcr2ns_scale++; +} + +/* + * FIXME: the timer needs some delay to stablize the counter capture + */ +static inline uint32_t timer_read(void) +{ + int delay = 100; + + __raw_writel(1, TIMERS_VIRT_BASE + TMR_CVWR(0)); + + while (delay--) + cpu_relax(); + + return __raw_readl(TIMERS_VIRT_BASE + TMR_CVWR(0)); +} + +unsigned long long sched_clock(void) +{ + unsigned long long v = cnt32_to_63(timer_read()); + return (v * tcr2ns_scale) >> TCR2NS_SCALE_FACTOR; +} + +static irqreturn_t timer_interrupt(int irq, void *dev_id) +{ + struct clock_event_device *c = dev_id; + + /* disable and clear pending interrupt status */ + __raw_writel(0x0, TIMERS_VIRT_BASE + TMR_IER(0)); + __raw_writel(0x1, TIMERS_VIRT_BASE + TMR_ICR(0)); + c->event_handler(c); + return IRQ_HANDLED; +} + +static int timer_set_next_event(unsigned long delta, + struct clock_event_device *dev) +{ + unsigned long flags, next; + + local_irq_save(flags); + + /* clear pending interrupt status and enable */ + __raw_writel(0x01, TIMERS_VIRT_BASE + TMR_ICR(0)); + __raw_writel(0x01, TIMERS_VIRT_BASE + TMR_IER(0)); + + next = timer_read() + delta; + __raw_writel(next, TIMERS_VIRT_BASE + TMR_TN_MM(0, 0)); + + local_irq_restore(flags); + return 0; +} + +static void timer_set_mode(enum clock_event_mode mode, + struct clock_event_device *dev) +{ + unsigned long flags; + + local_irq_save(flags); + switch (mode) { + case CLOCK_EVT_MODE_ONESHOT: + case CLOCK_EVT_MODE_UNUSED: + case CLOCK_EVT_MODE_SHUTDOWN: + /* disable the matching interrupt */ + __raw_writel(0x00, TIMERS_VIRT_BASE + TMR_IER(0)); + break; + case CLOCK_EVT_MODE_RESUME: + case CLOCK_EVT_MODE_PERIODIC: + break; + } + local_irq_restore(flags); +} + +static struct clock_event_device ckevt = { + .name = "clockevent", + .features = CLOCK_EVT_FEAT_ONESHOT, + .shift = 32, + .rating = 200, + .set_next_event = timer_set_next_event, + .set_mode = timer_set_mode, +}; + +static cycle_t clksrc_read(void) +{ + return timer_read(); +} + +static struct clocksource cksrc = { + .name = "clocksource", + .shift = 20, + .rating = 200, + .read = clksrc_read, + .mask = CLOCKSOURCE_MASK(32), + .flags = CLOCK_SOURCE_IS_CONTINUOUS, +}; + +static void __init timer_config(void) +{ + uint32_t ccr = __raw_readl(TIMERS_VIRT_BASE + TMR_CCR); + uint32_t cer = __raw_readl(TIMERS_VIRT_BASE + TMR_CER); + uint32_t cmr = __raw_readl(TIMERS_VIRT_BASE + TMR_CMR); + + __raw_writel(cer & ~0x1, TIMERS_VIRT_BASE + TMR_CER); /* disable */ + + ccr &= TMR_CCR_CS_0(0x3); + __raw_writel(ccr, TIMERS_VIRT_BASE + TMR_CCR); + + /* free-running mode */ + __raw_writel(cmr | 0x01, TIMERS_VIRT_BASE + TMR_CMR); + + __raw_writel(0x0, TIMERS_VIRT_BASE + TMR_PLCR(0)); /* free-running */ + __raw_writel(0x7, TIMERS_VIRT_BASE + TMR_ICR(0)); /* clear status */ + __raw_writel(0x0, TIMERS_VIRT_BASE + TMR_IER(0)); + + /* enable timer counter */ + __raw_writel(cer | 0x01, TIMERS_VIRT_BASE + TMR_CER); +} + +static struct irqaction timer_irq = { + .name = "timer", + .flags = IRQF_DISABLED | IRQF_TIMER | IRQF_IRQPOLL, + .handler = timer_interrupt, + .dev_id = &ckevt, +}; + +void __init timer_init(int irq) +{ + timer_config(); + + set_tcr2ns_scale(CLOCK_TICK_RATE); + + ckevt.mult = div_sc(CLOCK_TICK_RATE, NSEC_PER_SEC, ckevt.shift); + ckevt.max_delta_ns = clockevent_delta2ns(MAX_DELTA, &ckevt); + ckevt.min_delta_ns = clockevent_delta2ns(MIN_DELTA, &ckevt); + ckevt.cpumask = cpumask_of(0); + + cksrc.mult = clocksource_hz2mult(CLOCK_TICK_RATE, cksrc.shift); + + setup_irq(irq, &timer_irq); + + clocksource_register(&cksrc); + clockevents_register_device(&ckevt); +} |