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/*
* timer.c
*
* 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 <asm/io.h>
#include <linux/clocksource.h>
#include <linux/clockchips.h>
#include <linux/types.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/irq.h>
#include <mach/time.h>
#include <plat/ast-scu.h>
#define ASPEED_TIMER0_VA_BASE (IO_ADDRESS(AST_TIMER_BASE)+ASPEED_TIMER0_OFFSET)
#define ASPEED_TIMER1_VA_BASE (IO_ADDRESS(AST_TIMER_BASE)+ASPEED_TIMER1_OFFSET)
#define ASPEED_TIMER2_VA_BASE (IO_ADDRESS(AST_TIMER_BASE)+ASPEED_TIMER2_OFFSET)
#define ASPEED_TIMERC_VA_BASE (IO_ADDRESS(AST_TIMER_BASE)+ASPEED_TIMERRC_OFFSET)
#define ASPEED_TIMER_RELOAD_MAX 0xFFFFFFFF
#define ASPEED_TIMER_RELOAD_MIN 1
static struct clock_event_device clockevent_ast;
static inline unsigned long ast_timer_read_count(void *base)
{
volatile TimerStruct_t *timer = (volatile TimerStruct_t *)(base);
return timer->TimerValue;
}
/* change the timer count and load value (if requeseted) */
static inline void ast_timer_set_count(void *base, unsigned long count,
unsigned long reload)
{
volatile TimerStruct_t *timer = (volatile TimerStruct_t *)(base);
timer->TimerValue = count;
timer->TimerLoad = reload;
}
#define AST_TIMER_DISABLE 0
#define AST_TIMER_ENABLE 1
static inline void ast_timer0_ctrl(int enable)
{
volatile __u32 *timerc = (volatile __u32*) ASPEED_TIMERC_VA_BASE;
if (enable == AST_TIMER_ENABLE) {
*timerc |= TIMER0_ENABLE | TIMER0_RefExt;
} else {
*timerc &= ~TIMER0_ENABLE;
}
}
static inline void ast_timer1_ctrl(int enable)
{
volatile __u32 *timerc = (volatile __u32*) ASPEED_TIMERC_VA_BASE;
if (enable == AST_TIMER_ENABLE) {
*timerc |= TIMER1_ENABLE | TIMER1_RefExt;
} else {
*timerc &= ~TIMER1_ENABLE;
}
}
static inline void ast_timer_disable_all()
{
volatile __u32 *timerc = (volatile __u32*) ASPEED_TIMERC_VA_BASE;
*timerc = 0;
}
/*
* clocksource
*/
static irqreturn_t ast_clocksource_interrupt(int irq, void *dev_id)
{
return IRQ_HANDLED;
}
static struct irqaction ast_clocksource_irq = {
.name = "ast-clocksource",
.flags = IRQF_DISABLED | IRQF_TIMER,
.handler = ast_clocksource_interrupt,
};
static cycle_t read_cycles(void)
{
#if 1
return (cycles_t)(ASPEED_TIMER_RELOAD_MAX
- ast_timer_read_count(ASPEED_TIMER1_VA_BASE));
#else
return (cycles_t) ast_timer_read_count(ASPEED_TIMER1_VA_BASE);
#endif
}
static struct clocksource clocksource_ast = {
.name = "ast-clocksource",
.rating = 300,
.read = read_cycles,
.mask = CLOCKSOURCE_MASK(32),
.shift = 20,
.flags = CLOCK_SOURCE_IS_CONTINUOUS,
};
/*
* clockevent
*/
/* IRQ handler for the timer */
static irqreturn_t ast_clockevent_interrupt(int irq, void *dev_id)
{
struct clock_event_device *evt = &clockevent_ast;
evt->event_handler(evt);
return IRQ_HANDLED;
}
static struct irqaction ast_clockevent_irq = {
.name = "ast-clockevent",
.flags = IRQF_DISABLED | IRQF_TIMER,
.handler = ast_clockevent_interrupt,
};
static int ast_timer_set_next_event(unsigned long cycles,
struct clock_event_device *evt)
{
/* In this case, we shall not set the load value. */
ast_timer_set_count(ASPEED_TIMER0_VA_BASE, cycles, 0);
/* turn on the timer */
ast_timer0_ctrl(AST_TIMER_ENABLE);
return 0;
}
static void ast_timer_set_mode(enum clock_event_mode mode,
struct clock_event_device *evt)
{
/* stop timer first */
ast_timer0_ctrl(AST_TIMER_DISABLE);
switch (mode) {
case CLOCK_EVT_MODE_PERIODIC:
ast_timer_set_count(ASPEED_TIMER0_VA_BASE,
TIMER_RELOAD - 1, TIMER_RELOAD - 1);
ast_timer0_ctrl(AST_TIMER_ENABLE);
break;
case CLOCK_EVT_MODE_ONESHOT:
/*
* Leave the timer disabled, ast_timer_set_next_event() will
* enable it later
*/
break;
case CLOCK_EVT_MODE_UNUSED:
case CLOCK_EVT_MODE_SHUTDOWN:
case CLOCK_EVT_MODE_RESUME:
break;
}
}
static struct clock_event_device clockevent_ast = {
.name = "ast-clockevent",
.features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT,
.shift = 32,
.set_next_event = ast_timer_set_next_event,
.set_mode = ast_timer_set_mode,
};
/*
* Set up timer interrupt, and return the current time in seconds.
*/
static void __init ast_setup_timer(void)
{
/*
* Initialise to a known state (all timers off)
*/
ast_timer_disable_all();
/*
* For clock event, set the value and reload to 0, so that no interrupt even
* after enabling timer.
*/
ast_timer_set_count(ASPEED_TIMER0_VA_BASE, 0, 0);
/*
* For clock source, set the value and reload to the max
*/
ast_timer_set_count(ASPEED_TIMER1_VA_BASE,
ASPEED_TIMER_RELOAD_MAX, ASPEED_TIMER_RELOAD_MAX);
/* Enable timer */
ast_timer0_ctrl(AST_TIMER_ENABLE);
ast_timer1_ctrl(AST_TIMER_ENABLE);
ast_scu_show_system_info();
/* irqs happen for the system timer */
setup_irq(IRQ_TIMER0, &ast_clockevent_irq);
setup_irq(IRQ_TIMER1, &ast_clocksource_irq);
/* setup clocksource */
clocksource_ast.mult = clocksource_hz2mult(ASPEED_TIMER_CLKRATE,
clocksource_ast.shift);
if (clocksource_register(&clocksource_ast)) {
printk(KERN_ERR "Failed to register clock source %s", clocksource_ast.name);
}
/* setup clockevent */
clockevent_ast.mult = div_sc(ASPEED_TIMER_CLKRATE, NSEC_PER_SEC,
clockevent_ast.shift);
clockevent_ast.max_delta_ns = clockevent_delta2ns(ASPEED_TIMER_RELOAD_MAX,
&clockevent_ast);
clockevent_ast.min_delta_ns = clockevent_delta2ns(ASPEED_TIMER_RELOAD_MIN,
&clockevent_ast);
clockevent_ast.cpumask = cpumask_of_cpu(0);
clockevents_register_device(&clockevent_ast);
}
struct sys_timer ast_timer = {
.init = ast_setup_timer,
};
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