167 lines
4.0 KiB
C
167 lines
4.0 KiB
C
/*
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* This file is subject to the terms and conditions of the GNU General Public
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* License. See the file "COPYING" in the main directory of this archive
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* for more details.
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*
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* Copyright (C) 2012 MIPS Technologies, Inc. All rights reserved.
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*/
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#include <linux/clockchips.h>
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#include <linux/cpu.h>
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#include <linux/init.h>
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#include <linux/interrupt.h>
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#include <linux/irqchip/mips-gic.h>
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#include <linux/notifier.h>
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#include <linux/of_irq.h>
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#include <linux/percpu.h>
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#include <linux/smp.h>
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#include <linux/time.h>
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static DEFINE_PER_CPU(struct clock_event_device, gic_clockevent_device);
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static int gic_timer_irq;
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static unsigned int gic_frequency;
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static int gic_next_event(unsigned long delta, struct clock_event_device *evt)
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{
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u64 cnt;
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int res;
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cnt = gic_read_count();
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cnt += (u64)delta;
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gic_write_cpu_compare(cnt, cpumask_first(evt->cpumask));
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res = ((int)(gic_read_count() - cnt) >= 0) ? -ETIME : 0;
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return res;
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}
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static void gic_set_clock_mode(enum clock_event_mode mode,
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struct clock_event_device *evt)
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{
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/* Nothing to do ... */
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}
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static irqreturn_t gic_compare_interrupt(int irq, void *dev_id)
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{
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struct clock_event_device *cd = dev_id;
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gic_write_compare(gic_read_compare());
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cd->event_handler(cd);
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return IRQ_HANDLED;
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}
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struct irqaction gic_compare_irqaction = {
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.handler = gic_compare_interrupt,
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.percpu_dev_id = &gic_clockevent_device,
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.flags = IRQF_PERCPU | IRQF_TIMER,
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.name = "timer",
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};
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static void gic_clockevent_cpu_init(struct clock_event_device *cd)
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{
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unsigned int cpu = smp_processor_id();
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cd->name = "MIPS GIC";
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cd->features = CLOCK_EVT_FEAT_ONESHOT |
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CLOCK_EVT_FEAT_C3STOP;
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cd->rating = 350;
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cd->irq = gic_timer_irq;
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cd->cpumask = cpumask_of(cpu);
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cd->set_next_event = gic_next_event;
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cd->set_mode = gic_set_clock_mode;
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clockevents_config_and_register(cd, gic_frequency, 0x300, 0x7fffffff);
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enable_percpu_irq(gic_timer_irq, IRQ_TYPE_NONE);
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}
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static void gic_clockevent_cpu_exit(struct clock_event_device *cd)
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{
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disable_percpu_irq(gic_timer_irq);
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}
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static int gic_cpu_notifier(struct notifier_block *nb, unsigned long action,
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void *data)
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{
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switch (action & ~CPU_TASKS_FROZEN) {
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case CPU_STARTING:
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gic_clockevent_cpu_init(this_cpu_ptr(&gic_clockevent_device));
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break;
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case CPU_DYING:
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gic_clockevent_cpu_exit(this_cpu_ptr(&gic_clockevent_device));
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break;
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}
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return NOTIFY_OK;
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}
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static struct notifier_block gic_cpu_nb = {
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.notifier_call = gic_cpu_notifier,
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};
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static int gic_clockevent_init(void)
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{
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if (!cpu_has_counter || !gic_frequency)
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return -ENXIO;
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setup_percpu_irq(gic_timer_irq, &gic_compare_irqaction);
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register_cpu_notifier(&gic_cpu_nb);
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gic_clockevent_cpu_init(this_cpu_ptr(&gic_clockevent_device));
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return 0;
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}
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static cycle_t gic_hpt_read(struct clocksource *cs)
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{
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return gic_read_count();
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}
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static struct clocksource gic_clocksource = {
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.name = "GIC",
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.read = gic_hpt_read,
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.flags = CLOCK_SOURCE_IS_CONTINUOUS,
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};
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static void __init __gic_clocksource_init(void)
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{
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/* Set clocksource mask. */
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gic_clocksource.mask = CLOCKSOURCE_MASK(gic_get_count_width());
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/* Calculate a somewhat reasonable rating value. */
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gic_clocksource.rating = 200 + gic_frequency / 10000000;
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clocksource_register_hz(&gic_clocksource, gic_frequency);
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gic_clockevent_init();
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}
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void __init gic_clocksource_init(unsigned int frequency)
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{
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gic_frequency = frequency;
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gic_timer_irq = MIPS_GIC_IRQ_BASE +
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GIC_LOCAL_TO_HWIRQ(GIC_LOCAL_INT_COMPARE);
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__gic_clocksource_init();
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}
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static void __init gic_clocksource_of_init(struct device_node *node)
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{
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if (WARN_ON(!gic_present || !node->parent ||
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!of_device_is_compatible(node->parent, "mti,gic")))
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return;
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if (of_property_read_u32(node, "clock-frequency", &gic_frequency)) {
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pr_err("GIC frequency not specified.\n");
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return;
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}
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gic_timer_irq = irq_of_parse_and_map(node, 0);
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if (!gic_timer_irq) {
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pr_err("GIC timer IRQ not specified.\n");
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return;
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}
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__gic_clocksource_init();
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}
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CLOCKSOURCE_OF_DECLARE(mips_gic_timer, "mti,gic-timer",
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gic_clocksource_of_init);
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