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/*
* Actions Semi Owl timer
*
* Copyright 2012 Actions Semi Inc.
* Author: Actions Semi, Inc.
*
* Copyright (c) 2017 SUSE Linux GmbH
* Author: Andreas Färber
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the
* Free Software Foundation; either version 2 of the License, or (at your
* option) any later version.
*/
#include <linux/clk.h>
#include <linux/clockchips.h>
#include <linux/interrupt.h>
#include <linux/irq.h>
#include <linux/irqreturn.h>
#include <linux/sched_clock.h>
#include <linux/of.h>
#include <linux/of_address.h>
#include <linux/of_irq.h>
#define OWL_Tx_CTL 0x0
#define OWL_Tx_CMP 0x4
#define OWL_Tx_VAL 0x8
#define OWL_Tx_CTL_PD BIT(0)
#define OWL_Tx_CTL_INTEN BIT(1)
#define OWL_Tx_CTL_EN BIT(2)
static void __iomem *owl_timer_base;
static void __iomem *owl_clksrc_base;
static void __iomem *owl_clkevt_base;
static inline void owl_timer_reset(void __iomem *base)
{
writel(0, base + OWL_Tx_CTL);
writel(0, base + OWL_Tx_VAL);
writel(0, base + OWL_Tx_CMP);
}
static inline void owl_timer_set_enabled(void __iomem *base, bool enabled)
{
u32 ctl = readl(base + OWL_Tx_CTL);
/* PD bit is cleared when set */
ctl &= ~OWL_Tx_CTL_PD;
if (enabled)
ctl |= OWL_Tx_CTL_EN;
else
ctl &= ~OWL_Tx_CTL_EN;
writel(ctl, base + OWL_Tx_CTL);
}
static u64 notrace owl_timer_sched_read(void)
{
return (u64)readl(owl_clksrc_base + OWL_Tx_VAL);
}
static int owl_timer_set_state_shutdown(struct clock_event_device *evt)
{
owl_timer_set_enabled(owl_clkevt_base, false);
return 0;
}
static int owl_timer_set_state_oneshot(struct clock_event_device *evt)
{
owl_timer_reset(owl_clkevt_base);
return 0;
}
static int owl_timer_tick_resume(struct clock_event_device *evt)
{
return 0;
}
static int owl_timer_set_next_event(unsigned long evt,
struct clock_event_device *ev)
{
void __iomem *base = owl_clkevt_base;
owl_timer_set_enabled(base, false);
writel(OWL_Tx_CTL_INTEN, base + OWL_Tx_CTL);
writel(0, base + OWL_Tx_VAL);
writel(evt, base + OWL_Tx_CMP);
owl_timer_set_enabled(base, true);
return 0;
}
static struct clock_event_device owl_clockevent = {
.name = "owl_tick",
.rating = 200,
.features = CLOCK_EVT_FEAT_ONESHOT |
CLOCK_EVT_FEAT_DYNIRQ,
.set_state_shutdown = owl_timer_set_state_shutdown,
.set_state_oneshot = owl_timer_set_state_oneshot,
.tick_resume = owl_timer_tick_resume,
.set_next_event = owl_timer_set_next_event,
};
static irqreturn_t owl_timer1_interrupt(int irq, void *dev_id)
{
struct clock_event_device *evt = (struct clock_event_device *)dev_id;
writel(OWL_Tx_CTL_PD, owl_clkevt_base + OWL_Tx_CTL);
evt->event_handler(evt);
return IRQ_HANDLED;
}
static int __init owl_timer_init(struct device_node *node)
{
struct clk *clk;
unsigned long rate;
int timer1_irq, ret;
owl_timer_base = of_io_request_and_map(node, 0, "owl-timer");
if (IS_ERR(owl_timer_base)) {
pr_err("Can't map timer registers");
return PTR_ERR(owl_timer_base);
}
owl_clksrc_base = owl_timer_base + 0x08;
owl_clkevt_base = owl_timer_base + 0x14;
timer1_irq = of_irq_get_byname(node, "timer1");
if (timer1_irq <= 0) {
pr_err("Can't parse timer1 IRQ");
return -EINVAL;
}
clk = of_clk_get(node, 0);
if (IS_ERR(clk))
return PTR_ERR(clk);
rate = clk_get_rate(clk);
owl_timer_reset(owl_clksrc_base);
owl_timer_set_enabled(owl_clksrc_base, true);
sched_clock_register(owl_timer_sched_read, 32, rate);
clocksource_mmio_init(owl_clksrc_base + OWL_Tx_VAL, node->name,
rate, 200, 32, clocksource_mmio_readl_up);
owl_timer_reset(owl_clkevt_base);
ret = request_irq(timer1_irq, owl_timer1_interrupt, IRQF_TIMER,
"owl-timer", &owl_clockevent);
if (ret) {
pr_err("failed to request irq %d\n", timer1_irq);
return ret;
}
owl_clockevent.cpumask = cpumask_of(0);
owl_clockevent.irq = timer1_irq;
clockevents_config_and_register(&owl_clockevent, rate,
0xf, 0xffffffff);
return 0;
}
CLOCKSOURCE_OF_DECLARE(owl_s500, "actions,s500-timer", owl_timer_init);
CLOCKSOURCE_OF_DECLARE(owl_s900, "actions,s900-timer", owl_timer_init);
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