timer-sp.c
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/*
* linux/arch/arm/common/timer-sp.c
*
* Copyright (C) 1999 - 2003 ARM Limited
* Copyright (C) 2000 Deep Blue Solutions Ltd
*
* 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.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#include <linux/clk.h>
#include <linux/clocksource.h>
#include <linux/clockchips.h>
#include <linux/err.h>
#include <linux/interrupt.h>
#include <linux/irq.h>
#include <linux/io.h>
#include <asm/hardware/arm_timer.h>
static long __init sp804_get_clock_rate(const char *name)
{
struct clk *clk;
long rate;
int err;
clk = clk_get_sys("sp804", name);
if (IS_ERR(clk)) {
pr_err("sp804: %s clock not found: %d\n", name,
(int)PTR_ERR(clk));
return PTR_ERR(clk);
}
err = clk_prepare(clk);
if (err) {
pr_err("sp804: %s clock failed to prepare: %d\n", name, err);
clk_put(clk);
return err;
}
err = clk_enable(clk);
if (err) {
pr_err("sp804: %s clock failed to enable: %d\n", name, err);
clk_unprepare(clk);
clk_put(clk);
return err;
}
rate = clk_get_rate(clk);
if (rate < 0) {
pr_err("sp804: %s clock failed to get rate: %ld\n", name, rate);
clk_disable(clk);
clk_unprepare(clk);
clk_put(clk);
}
return rate;
}
void __init sp804_clocksource_init(void __iomem *base, const char *name)
{
long rate = sp804_get_clock_rate(name);
if (rate < 0)
return;
/* setup timer 0 as free-running clocksource */
writel(0, base + TIMER_CTRL);
writel(0xffffffff, base + TIMER_LOAD);
writel(0xffffffff, base + TIMER_VALUE);
writel(TIMER_CTRL_32BIT | TIMER_CTRL_ENABLE | TIMER_CTRL_PERIODIC,
base + TIMER_CTRL);
clocksource_mmio_init(base + TIMER_VALUE, name,
rate, 200, 32, clocksource_mmio_readl_down);
}
static void __iomem *clkevt_base;
static unsigned long clkevt_reload;
/*
* IRQ handler for the timer
*/
static irqreturn_t sp804_timer_interrupt(int irq, void *dev_id)
{
struct clock_event_device *evt = dev_id;
/* clear the interrupt */
writel(1, clkevt_base + TIMER_INTCLR);
evt->event_handler(evt);
return IRQ_HANDLED;
}
static void sp804_set_mode(enum clock_event_mode mode,
struct clock_event_device *evt)
{
unsigned long ctrl = TIMER_CTRL_32BIT | TIMER_CTRL_IE;
writel(ctrl, clkevt_base + TIMER_CTRL);
switch (mode) {
case CLOCK_EVT_MODE_PERIODIC:
writel(clkevt_reload, clkevt_base + TIMER_LOAD);
ctrl |= TIMER_CTRL_PERIODIC | TIMER_CTRL_ENABLE;
break;
case CLOCK_EVT_MODE_ONESHOT:
/* period set, and timer enabled in 'next_event' hook */
ctrl |= TIMER_CTRL_ONESHOT;
break;
case CLOCK_EVT_MODE_UNUSED:
case CLOCK_EVT_MODE_SHUTDOWN:
default:
break;
}
writel(ctrl, clkevt_base + TIMER_CTRL);
}
static int sp804_set_next_event(unsigned long next,
struct clock_event_device *evt)
{
unsigned long ctrl = readl(clkevt_base + TIMER_CTRL);
writel(next, clkevt_base + TIMER_LOAD);
writel(ctrl | TIMER_CTRL_ENABLE, clkevt_base + TIMER_CTRL);
return 0;
}
static struct clock_event_device sp804_clockevent = {
.features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT,
.set_mode = sp804_set_mode,
.set_next_event = sp804_set_next_event,
.rating = 300,
.cpumask = cpu_all_mask,
};
static struct irqaction sp804_timer_irq = {
.name = "timer",
.flags = IRQF_DISABLED | IRQF_TIMER | IRQF_IRQPOLL,
.handler = sp804_timer_interrupt,
.dev_id = &sp804_clockevent,
};
void __init sp804_clockevents_init(void __iomem *base, unsigned int irq,
const char *name)
{
struct clock_event_device *evt = &sp804_clockevent;
long rate = sp804_get_clock_rate(name);
if (rate < 0)
return;
clkevt_base = base;
clkevt_reload = DIV_ROUND_CLOSEST(rate, HZ);
evt->name = name;
evt->irq = irq;
setup_irq(irq, &sp804_timer_irq);
clockevents_config_and_register(evt, rate, 0xf, 0xffffffff);
}