287 lines
8.4 KiB
C
287 lines
8.4 KiB
C
/*
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* System timer for CSR SiRFprimaII
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*
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* Copyright (c) 2011 Cambridge Silicon Radio Limited, a CSR plc group company.
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*
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* Licensed under GPLv2 or later.
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*/
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#include <linux/kernel.h>
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#include <linux/interrupt.h>
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#include <linux/clockchips.h>
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#include <linux/clocksource.h>
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#include <linux/cpu.h>
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#include <linux/bitops.h>
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#include <linux/irq.h>
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#include <linux/clk.h>
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#include <linux/slab.h>
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#include <linux/of.h>
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#include <linux/of_irq.h>
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#include <linux/of_address.h>
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#include <linux/sched_clock.h>
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#define SIRFSOC_TIMER_32COUNTER_0_CTRL 0x0000
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#define SIRFSOC_TIMER_32COUNTER_1_CTRL 0x0004
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#define SIRFSOC_TIMER_MATCH_0 0x0018
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#define SIRFSOC_TIMER_MATCH_1 0x001c
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#define SIRFSOC_TIMER_COUNTER_0 0x0048
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#define SIRFSOC_TIMER_COUNTER_1 0x004c
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#define SIRFSOC_TIMER_INTR_STATUS 0x0060
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#define SIRFSOC_TIMER_WATCHDOG_EN 0x0064
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#define SIRFSOC_TIMER_64COUNTER_CTRL 0x0068
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#define SIRFSOC_TIMER_64COUNTER_LO 0x006c
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#define SIRFSOC_TIMER_64COUNTER_HI 0x0070
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#define SIRFSOC_TIMER_64COUNTER_LOAD_LO 0x0074
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#define SIRFSOC_TIMER_64COUNTER_LOAD_HI 0x0078
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#define SIRFSOC_TIMER_64COUNTER_RLATCHED_LO 0x007c
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#define SIRFSOC_TIMER_64COUNTER_RLATCHED_HI 0x0080
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#define SIRFSOC_TIMER_REG_CNT 6
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static unsigned long atlas7_timer_rate;
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static const u32 sirfsoc_timer_reg_list[SIRFSOC_TIMER_REG_CNT] = {
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SIRFSOC_TIMER_WATCHDOG_EN,
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SIRFSOC_TIMER_32COUNTER_0_CTRL,
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SIRFSOC_TIMER_32COUNTER_1_CTRL,
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SIRFSOC_TIMER_64COUNTER_CTRL,
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SIRFSOC_TIMER_64COUNTER_RLATCHED_LO,
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SIRFSOC_TIMER_64COUNTER_RLATCHED_HI,
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};
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static u32 sirfsoc_timer_reg_val[SIRFSOC_TIMER_REG_CNT];
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static void __iomem *sirfsoc_timer_base;
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/* disable count and interrupt */
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static inline void sirfsoc_timer_count_disable(int idx)
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{
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writel_relaxed(readl_relaxed(sirfsoc_timer_base + SIRFSOC_TIMER_32COUNTER_0_CTRL + 4 * idx) & ~0x7,
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sirfsoc_timer_base + SIRFSOC_TIMER_32COUNTER_0_CTRL + 4 * idx);
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}
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/* enable count and interrupt */
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static inline void sirfsoc_timer_count_enable(int idx)
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{
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writel_relaxed(readl_relaxed(sirfsoc_timer_base + SIRFSOC_TIMER_32COUNTER_0_CTRL + 4 * idx) | 0x3,
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sirfsoc_timer_base + SIRFSOC_TIMER_32COUNTER_0_CTRL + 4 * idx);
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}
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/* timer interrupt handler */
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static irqreturn_t sirfsoc_timer_interrupt(int irq, void *dev_id)
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{
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struct clock_event_device *ce = dev_id;
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int cpu = smp_processor_id();
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/* clear timer interrupt */
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writel_relaxed(BIT(cpu), sirfsoc_timer_base + SIRFSOC_TIMER_INTR_STATUS);
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if (clockevent_state_oneshot(ce))
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sirfsoc_timer_count_disable(cpu);
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ce->event_handler(ce);
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return IRQ_HANDLED;
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}
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/* read 64-bit timer counter */
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static u64 sirfsoc_timer_read(struct clocksource *cs)
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{
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u64 cycles;
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writel_relaxed((readl_relaxed(sirfsoc_timer_base + SIRFSOC_TIMER_64COUNTER_CTRL) |
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BIT(0)) & ~BIT(1), sirfsoc_timer_base + SIRFSOC_TIMER_64COUNTER_CTRL);
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cycles = readl_relaxed(sirfsoc_timer_base + SIRFSOC_TIMER_64COUNTER_RLATCHED_HI);
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cycles = (cycles << 32) | readl_relaxed(sirfsoc_timer_base + SIRFSOC_TIMER_64COUNTER_RLATCHED_LO);
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return cycles;
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}
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static int sirfsoc_timer_set_next_event(unsigned long delta,
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struct clock_event_device *ce)
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{
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int cpu = smp_processor_id();
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/* disable timer first, then modify the related registers */
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sirfsoc_timer_count_disable(cpu);
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writel_relaxed(0, sirfsoc_timer_base + SIRFSOC_TIMER_COUNTER_0 +
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4 * cpu);
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writel_relaxed(delta, sirfsoc_timer_base + SIRFSOC_TIMER_MATCH_0 +
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4 * cpu);
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/* enable the tick */
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sirfsoc_timer_count_enable(cpu);
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return 0;
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}
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/* Oneshot is enabled in set_next_event */
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static int sirfsoc_timer_shutdown(struct clock_event_device *evt)
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{
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sirfsoc_timer_count_disable(smp_processor_id());
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return 0;
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}
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static void sirfsoc_clocksource_suspend(struct clocksource *cs)
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{
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int i;
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for (i = 0; i < SIRFSOC_TIMER_REG_CNT; i++)
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sirfsoc_timer_reg_val[i] = readl_relaxed(sirfsoc_timer_base + sirfsoc_timer_reg_list[i]);
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}
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static void sirfsoc_clocksource_resume(struct clocksource *cs)
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{
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int i;
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for (i = 0; i < SIRFSOC_TIMER_REG_CNT - 2; i++)
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writel_relaxed(sirfsoc_timer_reg_val[i], sirfsoc_timer_base + sirfsoc_timer_reg_list[i]);
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writel_relaxed(sirfsoc_timer_reg_val[SIRFSOC_TIMER_REG_CNT - 2],
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sirfsoc_timer_base + SIRFSOC_TIMER_64COUNTER_LOAD_LO);
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writel_relaxed(sirfsoc_timer_reg_val[SIRFSOC_TIMER_REG_CNT - 1],
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sirfsoc_timer_base + SIRFSOC_TIMER_64COUNTER_LOAD_HI);
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writel_relaxed(readl_relaxed(sirfsoc_timer_base + SIRFSOC_TIMER_64COUNTER_CTRL) |
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BIT(1) | BIT(0), sirfsoc_timer_base + SIRFSOC_TIMER_64COUNTER_CTRL);
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}
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static struct clock_event_device __percpu *sirfsoc_clockevent;
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static struct clocksource sirfsoc_clocksource = {
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.name = "sirfsoc_clocksource",
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.rating = 200,
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.mask = CLOCKSOURCE_MASK(64),
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.flags = CLOCK_SOURCE_IS_CONTINUOUS,
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.read = sirfsoc_timer_read,
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.suspend = sirfsoc_clocksource_suspend,
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.resume = sirfsoc_clocksource_resume,
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};
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static struct irqaction sirfsoc_timer_irq = {
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.name = "sirfsoc_timer0",
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.flags = IRQF_TIMER | IRQF_NOBALANCING,
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.handler = sirfsoc_timer_interrupt,
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};
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static struct irqaction sirfsoc_timer1_irq = {
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.name = "sirfsoc_timer1",
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.flags = IRQF_TIMER | IRQF_NOBALANCING,
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.handler = sirfsoc_timer_interrupt,
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};
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static int sirfsoc_local_timer_starting_cpu(unsigned int cpu)
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{
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struct clock_event_device *ce = per_cpu_ptr(sirfsoc_clockevent, cpu);
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struct irqaction *action;
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if (cpu == 0)
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action = &sirfsoc_timer_irq;
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else
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action = &sirfsoc_timer1_irq;
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ce->irq = action->irq;
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ce->name = "local_timer";
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ce->features = CLOCK_EVT_FEAT_ONESHOT;
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ce->rating = 200;
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ce->set_state_shutdown = sirfsoc_timer_shutdown;
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ce->set_state_oneshot = sirfsoc_timer_shutdown;
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ce->tick_resume = sirfsoc_timer_shutdown;
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ce->set_next_event = sirfsoc_timer_set_next_event;
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clockevents_calc_mult_shift(ce, atlas7_timer_rate, 60);
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ce->max_delta_ns = clockevent_delta2ns(-2, ce);
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ce->max_delta_ticks = (unsigned long)-2;
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ce->min_delta_ns = clockevent_delta2ns(2, ce);
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ce->min_delta_ticks = 2;
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ce->cpumask = cpumask_of(cpu);
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action->dev_id = ce;
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BUG_ON(setup_irq(ce->irq, action));
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irq_force_affinity(action->irq, cpumask_of(cpu));
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clockevents_register_device(ce);
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return 0;
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}
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static int sirfsoc_local_timer_dying_cpu(unsigned int cpu)
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{
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sirfsoc_timer_count_disable(1);
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if (cpu == 0)
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remove_irq(sirfsoc_timer_irq.irq, &sirfsoc_timer_irq);
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else
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remove_irq(sirfsoc_timer1_irq.irq, &sirfsoc_timer1_irq);
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return 0;
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}
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static int __init sirfsoc_clockevent_init(void)
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{
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sirfsoc_clockevent = alloc_percpu(struct clock_event_device);
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BUG_ON(!sirfsoc_clockevent);
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/* Install and invoke hotplug callbacks */
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return cpuhp_setup_state(CPUHP_AP_MARCO_TIMER_STARTING,
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"clockevents/marco:starting",
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sirfsoc_local_timer_starting_cpu,
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sirfsoc_local_timer_dying_cpu);
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}
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/* initialize the kernel jiffy timer source */
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static int __init sirfsoc_atlas7_timer_init(struct device_node *np)
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{
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struct clk *clk;
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clk = of_clk_get(np, 0);
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BUG_ON(IS_ERR(clk));
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BUG_ON(clk_prepare_enable(clk));
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atlas7_timer_rate = clk_get_rate(clk);
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/* timer dividers: 0, not divided */
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writel_relaxed(0, sirfsoc_timer_base + SIRFSOC_TIMER_64COUNTER_CTRL);
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writel_relaxed(0, sirfsoc_timer_base + SIRFSOC_TIMER_32COUNTER_0_CTRL);
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writel_relaxed(0, sirfsoc_timer_base + SIRFSOC_TIMER_32COUNTER_1_CTRL);
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/* Initialize timer counters to 0 */
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writel_relaxed(0, sirfsoc_timer_base + SIRFSOC_TIMER_64COUNTER_LOAD_LO);
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writel_relaxed(0, sirfsoc_timer_base + SIRFSOC_TIMER_64COUNTER_LOAD_HI);
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writel_relaxed(readl_relaxed(sirfsoc_timer_base + SIRFSOC_TIMER_64COUNTER_CTRL) |
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BIT(1) | BIT(0), sirfsoc_timer_base + SIRFSOC_TIMER_64COUNTER_CTRL);
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writel_relaxed(0, sirfsoc_timer_base + SIRFSOC_TIMER_COUNTER_0);
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writel_relaxed(0, sirfsoc_timer_base + SIRFSOC_TIMER_COUNTER_1);
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/* Clear all interrupts */
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writel_relaxed(0xFFFF, sirfsoc_timer_base + SIRFSOC_TIMER_INTR_STATUS);
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BUG_ON(clocksource_register_hz(&sirfsoc_clocksource, atlas7_timer_rate));
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return sirfsoc_clockevent_init();
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}
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static int __init sirfsoc_of_timer_init(struct device_node *np)
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{
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sirfsoc_timer_base = of_iomap(np, 0);
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if (!sirfsoc_timer_base) {
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pr_err("unable to map timer cpu registers\n");
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return -ENXIO;
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}
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sirfsoc_timer_irq.irq = irq_of_parse_and_map(np, 0);
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if (!sirfsoc_timer_irq.irq) {
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pr_err("No irq passed for timer0 via DT\n");
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return -EINVAL;
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}
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sirfsoc_timer1_irq.irq = irq_of_parse_and_map(np, 1);
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if (!sirfsoc_timer1_irq.irq) {
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pr_err("No irq passed for timer1 via DT\n");
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return -EINVAL;
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}
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return sirfsoc_atlas7_timer_init(np);
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}
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TIMER_OF_DECLARE(sirfsoc_atlas7_timer, "sirf,atlas7-tick", sirfsoc_of_timer_init);
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