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/*
* Marvell Orion SoC timer handling.
*
* Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com>
*
* This file is licensed under the terms of the GNU General Public
* License version 2. This program is licensed "as is" without any
* warranty of any kind, whether express or implied.
*
* Timer 0 is used as free-running clocksource, while timer 1 is
* used as clock_event_device.
*/
#include <linux/kernel.h>
#include <linux/bitops.h>
#include <linux/clk.h>
#include <linux/clockchips.h>
#include <linux/delay.h>
#include <linux/interrupt.h>
#include <linux/of_address.h>
#include <linux/of_irq.h>
#include <linux/spinlock.h>
#include <linux/sched_clock.h>
#define TIMER_CTRL 0x00
#define TIMER0_EN BIT(0)
#define TIMER0_RELOAD_EN BIT(1)
#define TIMER1_EN BIT(2)
#define TIMER1_RELOAD_EN BIT(3)
#define TIMER0_RELOAD 0x10
#define TIMER0_VAL 0x14
#define TIMER1_RELOAD 0x18
#define TIMER1_VAL 0x1c
#define ORION_ONESHOT_MIN 1
#define ORION_ONESHOT_MAX 0xfffffffe
static void __iomem *timer_base;
static unsigned long notrace orion_read_timer(void)
{
return ~readl(timer_base + TIMER0_VAL);
}
static struct delay_timer orion_delay_timer = {
.read_current_timer = orion_read_timer,
};
static void orion_delay_timer_init(unsigned long rate)
{
orion_delay_timer.freq = rate;
register_current_timer_delay(&orion_delay_timer);
}
/*
* Free-running clocksource handling.
*/
static u64 notrace orion_read_sched_clock(void)
{
return ~readl(timer_base + TIMER0_VAL);
}
/*
* Clockevent handling.
*/
static u32 ticks_per_jiffy;
static int orion_clkevt_next_event(unsigned long delta,
struct clock_event_device *dev)
{
/* setup and enable one-shot timer */
writel(delta, timer_base + TIMER1_VAL);
atomic_io_modify(timer_base + TIMER_CTRL,
TIMER1_RELOAD_EN | TIMER1_EN, TIMER1_EN);
return 0;
}
static int orion_clkevt_shutdown(struct clock_event_device *dev)
{
/* disable timer */
atomic_io_modify(timer_base + TIMER_CTRL,
TIMER1_RELOAD_EN | TIMER1_EN, 0);
return 0;
}
static int orion_clkevt_set_periodic(struct clock_event_device *dev)
{
/* setup and enable periodic timer at 1/HZ intervals */
writel(ticks_per_jiffy - 1, timer_base + TIMER1_RELOAD);
writel(ticks_per_jiffy - 1, timer_base + TIMER1_VAL);
atomic_io_modify(timer_base + TIMER_CTRL,
TIMER1_RELOAD_EN | TIMER1_EN,
TIMER1_RELOAD_EN | TIMER1_EN);
return 0;
}
static struct clock_event_device orion_clkevt = {
.name = "orion_event",
.features = CLOCK_EVT_FEAT_ONESHOT |
CLOCK_EVT_FEAT_PERIODIC,
.shift = 32,
.rating = 300,
.set_next_event = orion_clkevt_next_event,
.set_state_shutdown = orion_clkevt_shutdown,
.set_state_periodic = orion_clkevt_set_periodic,
.set_state_oneshot = orion_clkevt_shutdown,
.tick_resume = orion_clkevt_shutdown,
};
static irqreturn_t orion_clkevt_irq_handler(int irq, void *dev_id)
{
orion_clkevt.event_handler(&orion_clkevt);
return IRQ_HANDLED;
}
static struct irqaction orion_clkevt_irq = {
.name = "orion_event",
.flags = IRQF_TIMER,
.handler = orion_clkevt_irq_handler,
};
static int __init orion_timer_init(struct device_node *np)
{
unsigned long rate;
struct clk *clk;
int irq, ret;
/* timer registers are shared with watchdog timer */
timer_base = of_iomap(np, 0);
if (!timer_base) {
pr_err("%s: unable to map resource\n", np->name);
return -ENXIO;
}
clk = of_clk_get(np, 0);
if (IS_ERR(clk)) {
pr_err("%s: unable to get clk\n", np->name);
return PTR_ERR(clk);
}
ret = clk_prepare_enable(clk);
if (ret) {
pr_err("Failed to prepare clock\n");
return ret;
}
/* we are only interested in timer1 irq */
irq = irq_of_parse_and_map(np, 1);
if (irq <= 0) {
pr_err("%s: unable to parse timer1 irq\n", np->name);
return -EINVAL;
}
rate = clk_get_rate(clk);
/* setup timer0 as free-running clocksource */
writel(~0, timer_base + TIMER0_VAL);
writel(~0, timer_base + TIMER0_RELOAD);
atomic_io_modify(timer_base + TIMER_CTRL,
TIMER0_RELOAD_EN | TIMER0_EN,
TIMER0_RELOAD_EN | TIMER0_EN);
ret = clocksource_mmio_init(timer_base + TIMER0_VAL,
"orion_clocksource", rate, 300, 32,
clocksource_mmio_readl_down);
if (ret) {
pr_err("Failed to initialize mmio timer\n");
return ret;
}
sched_clock_register(orion_read_sched_clock, 32, rate);
/* setup timer1 as clockevent timer */
ret = setup_irq(irq, &orion_clkevt_irq);
if (ret) {
pr_err("%s: unable to setup irq\n", np->name);
return ret;
}
ticks_per_jiffy = (clk_get_rate(clk) + HZ/2) / HZ;
orion_clkevt.cpumask = cpumask_of(0);
orion_clkevt.irq = irq;
clockevents_config_and_register(&orion_clkevt, rate,
ORION_ONESHOT_MIN, ORION_ONESHOT_MAX);
orion_delay_timer_init(rate);
return 0;
}
CLOCKSOURCE_OF_DECLARE(orion_timer, "marvell,orion-timer", orion_timer_init);
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