rockchip_timer.c
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/*
* Rockchip timer support
*
* Copyright (C) Daniel Lezcano <daniel.lezcano@linaro.org>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#include <linux/clk.h>
#include <linux/clockchips.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/of.h>
#include <linux/of_address.h>
#include <linux/of_irq.h>
#define TIMER_NAME "rk_timer"
#define TIMER_LOAD_COUNT0 0x00
#define TIMER_LOAD_COUNT1 0x04
#define TIMER_CONTROL_REG 0x10
#define TIMER_INT_STATUS 0x18
#define TIMER_DISABLE 0x0
#define TIMER_ENABLE 0x1
#define TIMER_MODE_FREE_RUNNING (0 << 1)
#define TIMER_MODE_USER_DEFINED_COUNT (1 << 1)
#define TIMER_INT_UNMASK (1 << 2)
struct bc_timer {
struct clock_event_device ce;
void __iomem *base;
u32 freq;
};
static struct bc_timer bc_timer;
static inline struct bc_timer *rk_timer(struct clock_event_device *ce)
{
return container_of(ce, struct bc_timer, ce);
}
static inline void __iomem *rk_base(struct clock_event_device *ce)
{
return rk_timer(ce)->base;
}
static inline void rk_timer_disable(struct clock_event_device *ce)
{
writel_relaxed(TIMER_DISABLE, rk_base(ce) + TIMER_CONTROL_REG);
dsb();
}
static inline void rk_timer_enable(struct clock_event_device *ce, u32 flags)
{
writel_relaxed(TIMER_ENABLE | TIMER_INT_UNMASK | flags,
rk_base(ce) + TIMER_CONTROL_REG);
dsb();
}
static void rk_timer_update_counter(unsigned long cycles,
struct clock_event_device *ce)
{
writel_relaxed(cycles, rk_base(ce) + TIMER_LOAD_COUNT0);
writel_relaxed(0, rk_base(ce) + TIMER_LOAD_COUNT1);
dsb();
}
static void rk_timer_interrupt_clear(struct clock_event_device *ce)
{
writel_relaxed(1, rk_base(ce) + TIMER_INT_STATUS);
dsb();
}
static inline int rk_timer_set_next_event(unsigned long cycles,
struct clock_event_device *ce)
{
rk_timer_disable(ce);
rk_timer_update_counter(cycles, ce);
rk_timer_enable(ce, TIMER_MODE_USER_DEFINED_COUNT);
return 0;
}
static inline void rk_timer_set_mode(enum clock_event_mode mode,
struct clock_event_device *ce)
{
switch (mode) {
case CLOCK_EVT_MODE_PERIODIC:
rk_timer_disable(ce);
rk_timer_update_counter(rk_timer(ce)->freq / HZ - 1, ce);
rk_timer_enable(ce, TIMER_MODE_FREE_RUNNING);
break;
case CLOCK_EVT_MODE_ONESHOT:
case CLOCK_EVT_MODE_RESUME:
break;
case CLOCK_EVT_MODE_UNUSED:
case CLOCK_EVT_MODE_SHUTDOWN:
rk_timer_disable(ce);
break;
}
}
static irqreturn_t rk_timer_interrupt(int irq, void *dev_id)
{
struct clock_event_device *ce = dev_id;
rk_timer_interrupt_clear(ce);
if (ce->mode == CLOCK_EVT_MODE_ONESHOT)
rk_timer_disable(ce);
ce->event_handler(ce);
return IRQ_HANDLED;
}
static void __init rk_timer_init(struct device_node *np)
{
struct clock_event_device *ce = &bc_timer.ce;
struct clk *timer_clk;
struct clk *pclk;
int ret, irq;
bc_timer.base = of_iomap(np, 0);
if (!bc_timer.base) {
pr_err("Failed to get base address for '%s'\n", TIMER_NAME);
return;
}
pclk = of_clk_get_by_name(np, "pclk");
if (IS_ERR(pclk)) {
pr_err("Failed to get pclk for '%s'\n", TIMER_NAME);
return;
}
if (clk_prepare_enable(pclk)) {
pr_err("Failed to enable pclk for '%s'\n", TIMER_NAME);
return;
}
timer_clk = of_clk_get_by_name(np, "timer");
if (IS_ERR(timer_clk)) {
pr_err("Failed to get timer clock for '%s'\n", TIMER_NAME);
return;
}
if (clk_prepare_enable(timer_clk)) {
pr_err("Failed to enable timer clock\n");
return;
}
bc_timer.freq = clk_get_rate(timer_clk);
irq = irq_of_parse_and_map(np, 0);
if (irq == NO_IRQ) {
pr_err("Failed to map interrupts for '%s'\n", TIMER_NAME);
return;
}
ce->name = TIMER_NAME;
ce->features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT;
ce->set_next_event = rk_timer_set_next_event;
ce->set_mode = rk_timer_set_mode;
ce->irq = irq;
ce->cpumask = cpumask_of(0);
ce->rating = 250;
rk_timer_interrupt_clear(ce);
rk_timer_disable(ce);
ret = request_irq(irq, rk_timer_interrupt, IRQF_TIMER, TIMER_NAME, ce);
if (ret) {
pr_err("Failed to initialize '%s': %d\n", TIMER_NAME, ret);
return;
}
clockevents_config_and_register(ce, bc_timer.freq, 1, UINT_MAX);
}
CLOCKSOURCE_OF_DECLARE(rk_timer, "rockchip,rk3288-timer", rk_timer_init);