diff options
Diffstat (limited to 'arch/arm/mach-ux500/localtimer.c')
| -rwxr-xr-x | arch/arm/mach-ux500/localtimer.c | 207 |
1 files changed, 207 insertions, 0 deletions
diff --git a/arch/arm/mach-ux500/localtimer.c b/arch/arm/mach-ux500/localtimer.c new file mode 100755 index 00000000000..b59e14697ca --- /dev/null +++ b/arch/arm/mach-ux500/localtimer.c @@ -0,0 +1,207 @@ +/* + * Copyright (C) 2009 ST Ericsson. + * This file is based on realview platform + * Copyright (C) 2002 ARM Ltd. + * + * 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/delay.h> +#include <linux/device.h> +#include <linux/smp.h> +#include <linux/jiffies.h> +#include <linux/percpu.h> +#include <linux/clockchips.h> +#include <linux/irq.h> + +#include <asm/hardware/arm_twd.h> +#include <asm/hardware/gic.h> +#include <mach/hardware.h> +#include <asm/io.h> +#include <asm/irq.h> +#include <mach/mtu.h> + +static DEFINE_PER_CPU(struct clock_event_device, local_clockevent); + +/* + * Used on SMP for either the local timer or IPI_TIMER + */ +void local_timer_interrupt(void) +{ + struct clock_event_device *clk = &__get_cpu_var(local_clockevent); + + clk->event_handler(clk); +} + +#ifdef CONFIG_LOCAL_TIMERS + +/* set up by the platform code */ +void __iomem *twd_base; + +static unsigned long mpcore_timer_rate; + +static void local_timer_set_mode(enum clock_event_mode mode, + struct clock_event_device *clk) +{ + unsigned long ctrl; + + switch (mode) { + case CLOCK_EVT_MODE_PERIODIC: + /* timer load already set up */ + ctrl = TWD_TIMER_CONTROL_ENABLE | TWD_TIMER_CONTROL_IT_ENABLE + | TWD_TIMER_CONTROL_PERIODIC; + break; + case CLOCK_EVT_MODE_ONESHOT: + /* period set, and timer enabled in 'next_event' hook */ + ctrl = TWD_TIMER_CONTROL_IT_ENABLE | TWD_TIMER_CONTROL_ONESHOT; + break; + case CLOCK_EVT_MODE_UNUSED: + case CLOCK_EVT_MODE_SHUTDOWN: + default: + ctrl = 0; + } + + __raw_writel(ctrl, twd_base + TWD_TIMER_CONTROL); +} + +static int local_timer_set_next_event(unsigned long evt, + struct clock_event_device *unused) +{ + unsigned long ctrl = __raw_readl(twd_base + TWD_TIMER_CONTROL); + + __raw_writel(evt, twd_base + TWD_TIMER_COUNTER); + __raw_writel(ctrl | TWD_TIMER_CONTROL_ENABLE, + twd_base + TWD_TIMER_CONTROL); + + return 0; +} + +/* + * local_timer_ack: checks for a local timer interrupt. + * + * If a local timer interrupt has occurred, acknowledge and return 1. + * Otherwise, return 0. + */ +int local_timer_ack(void) +{ + if (__raw_readl(twd_base + TWD_TIMER_INTSTAT)) { + __raw_writel(1, twd_base + TWD_TIMER_INTSTAT); + return 1; + } + return 0; +} + +static void __cpuinit twd_calibrate_rate(void) +{ + unsigned long load, count; + u64 waitjiffies; + + /* + * If this is the first time round, we need to work out how fast + * the timer ticks + */ + if (mpcore_timer_rate == 0) { + printk("Calibrating local timer... "); + + /* Wait for a tick to start */ + waitjiffies = get_jiffies_64() + 1; + + while (get_jiffies_64() < waitjiffies) + udelay(10); + + /* OK, now the tick has started, let's get the timer going */ + waitjiffies += 5; + + /* enable, no interrupt or reload */ + __raw_writel(0x1, twd_base + TWD_TIMER_CONTROL); + + /* maximum value */ + __raw_writel(0xFFFFFFFFU, twd_base + TWD_TIMER_COUNTER); + + while (get_jiffies_64() < waitjiffies) + udelay(10); + + count = __raw_readl(twd_base + TWD_TIMER_COUNTER); + + mpcore_timer_rate = (0xFFFFFFFFU - count) * (HZ / 5); + + printk("%lu.%02luMHz.\n", mpcore_timer_rate / 1000000, + (mpcore_timer_rate / 100000) % 100); + } + + load = mpcore_timer_rate / HZ; + + __raw_writel(load, twd_base + TWD_TIMER_LOAD); +} + +extern struct mtu_struct mtu_timer_tick; + +/* + * Setup the local clock events for a CPU. + */ +void __cpuinit local_timer_setup(void) +{ + unsigned int cpu = smp_processor_id(); + struct clock_event_device *clk = &per_cpu(local_clockevent, cpu); + unsigned long flags; + + twd_calibrate_rate(); + + clk->name = "local_timer"; + clk->features = CLOCK_EVT_FEAT_PERIODIC | + CLOCK_EVT_FEAT_ONESHOT | + CLOCK_EVT_FEAT_C3STOP; + clk->rating = 550; + clk->set_mode = local_timer_set_mode; + clk->set_next_event = local_timer_set_next_event; + clk->irq = IRQ_LOCALTIMER; + clk->cpumask = cpumask_of(cpu); + clk->shift = 20; + clk->mult = div_sc(mpcore_timer_rate, NSEC_PER_SEC, + clk->shift); + clk->max_delta_ns = clockevent_delta2ns(0xffffffff, clk); + clk->min_delta_ns = clockevent_delta2ns(0xf, clk); + clk->broadcast = smp_timer_broadcast; + + /* Make sure our local interrupt controller has this enabled */ + local_irq_save(flags); + get_irq_chip(IRQ_LOCALTIMER)->unmask(IRQ_LOCALTIMER); + local_irq_restore(flags); + + clockevents_register_device(clk); +} + +/* + * take a local timer down + */ +void __cpuexit local_timer_stop(void) +{ + __raw_writel(0, twd_base + TWD_TIMER_CONTROL); +} + +#else /* CONFIG_LOCAL_TIMERS */ + +static void dummy_timer_set_mode(enum clock_event_mode mode, + struct clock_event_device *clk) +{ +} + +void __cpuinit local_timer_setup(void) +{ + unsigned int cpu = smp_processor_id(); + struct clock_event_device *clk = &per_cpu(local_clockevent, cpu); + + clk->name = "dummy_timer"; + clk->features = CLOCK_EVT_FEAT_DUMMY; + clk->rating = 200; + clk->set_mode = dummy_timer_set_mode; + clk->broadcast = smp_timer_broadcast; + clk->cpumask = cpumask_of(cpu); + clk->mult = 1; + + clockevents_register_device(clk); +} +#endif /* !CONFIG_LOCAL_TIMERS */ |