https://github.com/torvalds/linux
Tip revision: 1a695a905c18548062509178b98bc91e67510864 authored by Linus Torvalds on 29 May 2016, 16:29:24 UTC
Linux 4.7-rc1
Linux 4.7-rc1
Tip revision: 1a695a9
timer-atlas7.c
/*
* System timer for CSR SiRFprimaII
*
* Copyright (c) 2011 Cambridge Silicon Radio Limited, a CSR plc group company.
*
* Licensed under GPLv2 or later.
*/
#include <linux/kernel.h>
#include <linux/interrupt.h>
#include <linux/clockchips.h>
#include <linux/clocksource.h>
#include <linux/cpu.h>
#include <linux/bitops.h>
#include <linux/irq.h>
#include <linux/clk.h>
#include <linux/slab.h>
#include <linux/of.h>
#include <linux/of_irq.h>
#include <linux/of_address.h>
#include <linux/sched_clock.h>
#define SIRFSOC_TIMER_32COUNTER_0_CTRL 0x0000
#define SIRFSOC_TIMER_32COUNTER_1_CTRL 0x0004
#define SIRFSOC_TIMER_MATCH_0 0x0018
#define SIRFSOC_TIMER_MATCH_1 0x001c
#define SIRFSOC_TIMER_COUNTER_0 0x0048
#define SIRFSOC_TIMER_COUNTER_1 0x004c
#define SIRFSOC_TIMER_INTR_STATUS 0x0060
#define SIRFSOC_TIMER_WATCHDOG_EN 0x0064
#define SIRFSOC_TIMER_64COUNTER_CTRL 0x0068
#define SIRFSOC_TIMER_64COUNTER_LO 0x006c
#define SIRFSOC_TIMER_64COUNTER_HI 0x0070
#define SIRFSOC_TIMER_64COUNTER_LOAD_LO 0x0074
#define SIRFSOC_TIMER_64COUNTER_LOAD_HI 0x0078
#define SIRFSOC_TIMER_64COUNTER_RLATCHED_LO 0x007c
#define SIRFSOC_TIMER_64COUNTER_RLATCHED_HI 0x0080
#define SIRFSOC_TIMER_REG_CNT 6
static unsigned long atlas7_timer_rate;
static const u32 sirfsoc_timer_reg_list[SIRFSOC_TIMER_REG_CNT] = {
SIRFSOC_TIMER_WATCHDOG_EN,
SIRFSOC_TIMER_32COUNTER_0_CTRL,
SIRFSOC_TIMER_32COUNTER_1_CTRL,
SIRFSOC_TIMER_64COUNTER_CTRL,
SIRFSOC_TIMER_64COUNTER_RLATCHED_LO,
SIRFSOC_TIMER_64COUNTER_RLATCHED_HI,
};
static u32 sirfsoc_timer_reg_val[SIRFSOC_TIMER_REG_CNT];
static void __iomem *sirfsoc_timer_base;
/* disable count and interrupt */
static inline void sirfsoc_timer_count_disable(int idx)
{
writel_relaxed(readl_relaxed(sirfsoc_timer_base + SIRFSOC_TIMER_32COUNTER_0_CTRL + 4 * idx) & ~0x7,
sirfsoc_timer_base + SIRFSOC_TIMER_32COUNTER_0_CTRL + 4 * idx);
}
/* enable count and interrupt */
static inline void sirfsoc_timer_count_enable(int idx)
{
writel_relaxed(readl_relaxed(sirfsoc_timer_base + SIRFSOC_TIMER_32COUNTER_0_CTRL + 4 * idx) | 0x3,
sirfsoc_timer_base + SIRFSOC_TIMER_32COUNTER_0_CTRL + 4 * idx);
}
/* timer interrupt handler */
static irqreturn_t sirfsoc_timer_interrupt(int irq, void *dev_id)
{
struct clock_event_device *ce = dev_id;
int cpu = smp_processor_id();
/* clear timer interrupt */
writel_relaxed(BIT(cpu), sirfsoc_timer_base + SIRFSOC_TIMER_INTR_STATUS);
if (clockevent_state_oneshot(ce))
sirfsoc_timer_count_disable(cpu);
ce->event_handler(ce);
return IRQ_HANDLED;
}
/* read 64-bit timer counter */
static cycle_t sirfsoc_timer_read(struct clocksource *cs)
{
u64 cycles;
writel_relaxed((readl_relaxed(sirfsoc_timer_base + SIRFSOC_TIMER_64COUNTER_CTRL) |
BIT(0)) & ~BIT(1), sirfsoc_timer_base + SIRFSOC_TIMER_64COUNTER_CTRL);
cycles = readl_relaxed(sirfsoc_timer_base + SIRFSOC_TIMER_64COUNTER_RLATCHED_HI);
cycles = (cycles << 32) | readl_relaxed(sirfsoc_timer_base + SIRFSOC_TIMER_64COUNTER_RLATCHED_LO);
return cycles;
}
static int sirfsoc_timer_set_next_event(unsigned long delta,
struct clock_event_device *ce)
{
int cpu = smp_processor_id();
/* disable timer first, then modify the related registers */
sirfsoc_timer_count_disable(cpu);
writel_relaxed(0, sirfsoc_timer_base + SIRFSOC_TIMER_COUNTER_0 +
4 * cpu);
writel_relaxed(delta, sirfsoc_timer_base + SIRFSOC_TIMER_MATCH_0 +
4 * cpu);
/* enable the tick */
sirfsoc_timer_count_enable(cpu);
return 0;
}
/* Oneshot is enabled in set_next_event */
static int sirfsoc_timer_shutdown(struct clock_event_device *evt)
{
sirfsoc_timer_count_disable(smp_processor_id());
return 0;
}
static void sirfsoc_clocksource_suspend(struct clocksource *cs)
{
int i;
for (i = 0; i < SIRFSOC_TIMER_REG_CNT; i++)
sirfsoc_timer_reg_val[i] = readl_relaxed(sirfsoc_timer_base + sirfsoc_timer_reg_list[i]);
}
static void sirfsoc_clocksource_resume(struct clocksource *cs)
{
int i;
for (i = 0; i < SIRFSOC_TIMER_REG_CNT - 2; i++)
writel_relaxed(sirfsoc_timer_reg_val[i], sirfsoc_timer_base + sirfsoc_timer_reg_list[i]);
writel_relaxed(sirfsoc_timer_reg_val[SIRFSOC_TIMER_REG_CNT - 2],
sirfsoc_timer_base + SIRFSOC_TIMER_64COUNTER_LOAD_LO);
writel_relaxed(sirfsoc_timer_reg_val[SIRFSOC_TIMER_REG_CNT - 1],
sirfsoc_timer_base + SIRFSOC_TIMER_64COUNTER_LOAD_HI);
writel_relaxed(readl_relaxed(sirfsoc_timer_base + SIRFSOC_TIMER_64COUNTER_CTRL) |
BIT(1) | BIT(0), sirfsoc_timer_base + SIRFSOC_TIMER_64COUNTER_CTRL);
}
static struct clock_event_device __percpu *sirfsoc_clockevent;
static struct clocksource sirfsoc_clocksource = {
.name = "sirfsoc_clocksource",
.rating = 200,
.mask = CLOCKSOURCE_MASK(64),
.flags = CLOCK_SOURCE_IS_CONTINUOUS,
.read = sirfsoc_timer_read,
.suspend = sirfsoc_clocksource_suspend,
.resume = sirfsoc_clocksource_resume,
};
static struct irqaction sirfsoc_timer_irq = {
.name = "sirfsoc_timer0",
.flags = IRQF_TIMER | IRQF_NOBALANCING,
.handler = sirfsoc_timer_interrupt,
};
static struct irqaction sirfsoc_timer1_irq = {
.name = "sirfsoc_timer1",
.flags = IRQF_TIMER | IRQF_NOBALANCING,
.handler = sirfsoc_timer_interrupt,
};
static int sirfsoc_local_timer_setup(struct clock_event_device *ce)
{
int cpu = smp_processor_id();
struct irqaction *action;
if (cpu == 0)
action = &sirfsoc_timer_irq;
else
action = &sirfsoc_timer1_irq;
ce->irq = action->irq;
ce->name = "local_timer";
ce->features = CLOCK_EVT_FEAT_ONESHOT;
ce->rating = 200;
ce->set_state_shutdown = sirfsoc_timer_shutdown;
ce->set_state_oneshot = sirfsoc_timer_shutdown;
ce->tick_resume = sirfsoc_timer_shutdown;
ce->set_next_event = sirfsoc_timer_set_next_event;
clockevents_calc_mult_shift(ce, atlas7_timer_rate, 60);
ce->max_delta_ns = clockevent_delta2ns(-2, ce);
ce->min_delta_ns = clockevent_delta2ns(2, ce);
ce->cpumask = cpumask_of(cpu);
action->dev_id = ce;
BUG_ON(setup_irq(ce->irq, action));
irq_force_affinity(action->irq, cpumask_of(cpu));
clockevents_register_device(ce);
return 0;
}
static void sirfsoc_local_timer_stop(struct clock_event_device *ce)
{
int cpu = smp_processor_id();
sirfsoc_timer_count_disable(1);
if (cpu == 0)
remove_irq(sirfsoc_timer_irq.irq, &sirfsoc_timer_irq);
else
remove_irq(sirfsoc_timer1_irq.irq, &sirfsoc_timer1_irq);
}
static int sirfsoc_cpu_notify(struct notifier_block *self,
unsigned long action, void *hcpu)
{
/*
* Grab cpu pointer in each case to avoid spurious
* preemptible warnings
*/
switch (action & ~CPU_TASKS_FROZEN) {
case CPU_STARTING:
sirfsoc_local_timer_setup(this_cpu_ptr(sirfsoc_clockevent));
break;
case CPU_DYING:
sirfsoc_local_timer_stop(this_cpu_ptr(sirfsoc_clockevent));
break;
}
return NOTIFY_OK;
}
static struct notifier_block sirfsoc_cpu_nb = {
.notifier_call = sirfsoc_cpu_notify,
};
static void __init sirfsoc_clockevent_init(void)
{
sirfsoc_clockevent = alloc_percpu(struct clock_event_device);
BUG_ON(!sirfsoc_clockevent);
BUG_ON(register_cpu_notifier(&sirfsoc_cpu_nb));
/* Immediately configure the timer on the boot CPU */
sirfsoc_local_timer_setup(this_cpu_ptr(sirfsoc_clockevent));
}
/* initialize the kernel jiffy timer source */
static void __init sirfsoc_atlas7_timer_init(struct device_node *np)
{
struct clk *clk;
clk = of_clk_get(np, 0);
BUG_ON(IS_ERR(clk));
BUG_ON(clk_prepare_enable(clk));
atlas7_timer_rate = clk_get_rate(clk);
/* timer dividers: 0, not divided */
writel_relaxed(0, sirfsoc_timer_base + SIRFSOC_TIMER_64COUNTER_CTRL);
writel_relaxed(0, sirfsoc_timer_base + SIRFSOC_TIMER_32COUNTER_0_CTRL);
writel_relaxed(0, sirfsoc_timer_base + SIRFSOC_TIMER_32COUNTER_1_CTRL);
/* Initialize timer counters to 0 */
writel_relaxed(0, sirfsoc_timer_base + SIRFSOC_TIMER_64COUNTER_LOAD_LO);
writel_relaxed(0, sirfsoc_timer_base + SIRFSOC_TIMER_64COUNTER_LOAD_HI);
writel_relaxed(readl_relaxed(sirfsoc_timer_base + SIRFSOC_TIMER_64COUNTER_CTRL) |
BIT(1) | BIT(0), sirfsoc_timer_base + SIRFSOC_TIMER_64COUNTER_CTRL);
writel_relaxed(0, sirfsoc_timer_base + SIRFSOC_TIMER_COUNTER_0);
writel_relaxed(0, sirfsoc_timer_base + SIRFSOC_TIMER_COUNTER_1);
/* Clear all interrupts */
writel_relaxed(0xFFFF, sirfsoc_timer_base + SIRFSOC_TIMER_INTR_STATUS);
BUG_ON(clocksource_register_hz(&sirfsoc_clocksource, atlas7_timer_rate));
sirfsoc_clockevent_init();
}
static void __init sirfsoc_of_timer_init(struct device_node *np)
{
sirfsoc_timer_base = of_iomap(np, 0);
if (!sirfsoc_timer_base)
panic("unable to map timer cpu registers\n");
sirfsoc_timer_irq.irq = irq_of_parse_and_map(np, 0);
if (!sirfsoc_timer_irq.irq)
panic("No irq passed for timer0 via DT\n");
sirfsoc_timer1_irq.irq = irq_of_parse_and_map(np, 1);
if (!sirfsoc_timer1_irq.irq)
panic("No irq passed for timer1 via DT\n");
sirfsoc_atlas7_timer_init(np);
}
CLOCKSOURCE_OF_DECLARE(sirfsoc_atlas7_timer, "sirf,atlas7-tick", sirfsoc_of_timer_init);