116 lines
2.4 KiB
C
116 lines
2.4 KiB
C
/*
|
|
* linux/arch/arm/mach-imx/time.c
|
|
*
|
|
* Copyright (C) 2000-2001 Deep Blue Solutions
|
|
* Copyright (C) 2002 Shane Nay (shane@minirl.com)
|
|
*
|
|
* 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/kernel.h>
|
|
#include <linux/sched.h>
|
|
#include <linux/init.h>
|
|
#include <linux/interrupt.h>
|
|
#include <linux/irq.h>
|
|
#include <linux/time.h>
|
|
#include <linux/clocksource.h>
|
|
|
|
#include <asm/hardware.h>
|
|
#include <asm/io.h>
|
|
#include <asm/leds.h>
|
|
#include <asm/irq.h>
|
|
#include <asm/mach/time.h>
|
|
|
|
/* Use timer 1 as system timer */
|
|
#define TIMER_BASE IMX_TIM1_BASE
|
|
|
|
static unsigned long evt_diff;
|
|
|
|
/*
|
|
* IRQ handler for the timer
|
|
*/
|
|
static irqreturn_t
|
|
imx_timer_interrupt(int irq, void *dev_id)
|
|
{
|
|
uint32_t tstat;
|
|
|
|
/* clear the interrupt */
|
|
tstat = IMX_TSTAT(TIMER_BASE);
|
|
IMX_TSTAT(TIMER_BASE) = 0;
|
|
|
|
if (tstat & TSTAT_COMP) {
|
|
do {
|
|
|
|
write_seqlock(&xtime_lock);
|
|
timer_tick();
|
|
write_sequnlock(&xtime_lock);
|
|
IMX_TCMP(TIMER_BASE) += evt_diff;
|
|
|
|
} while (unlikely((int32_t)(IMX_TCMP(TIMER_BASE)
|
|
- IMX_TCN(TIMER_BASE)) < 0));
|
|
}
|
|
|
|
return IRQ_HANDLED;
|
|
}
|
|
|
|
static struct irqaction imx_timer_irq = {
|
|
.name = "i.MX Timer Tick",
|
|
.flags = IRQF_DISABLED | IRQF_TIMER,
|
|
.handler = imx_timer_interrupt,
|
|
};
|
|
|
|
/*
|
|
* Set up timer hardware into expected mode and state.
|
|
*/
|
|
static void __init imx_timer_hardware_init(void)
|
|
{
|
|
/*
|
|
* Initialise to a known state (all timers off, and timing reset)
|
|
*/
|
|
IMX_TCTL(TIMER_BASE) = 0;
|
|
IMX_TPRER(TIMER_BASE) = 0;
|
|
IMX_TCMP(TIMER_BASE) = LATCH - 1;
|
|
|
|
IMX_TCTL(TIMER_BASE) = TCTL_FRR | TCTL_CLK_PCLK1 | TCTL_IRQEN | TCTL_TEN;
|
|
evt_diff = LATCH;
|
|
}
|
|
|
|
cycle_t imx_get_cycles(void)
|
|
{
|
|
return IMX_TCN(TIMER_BASE);
|
|
}
|
|
|
|
static struct clocksource clocksource_imx = {
|
|
.name = "imx_timer1",
|
|
.rating = 200,
|
|
.read = imx_get_cycles,
|
|
.mask = 0xFFFFFFFF,
|
|
.shift = 20,
|
|
.flags = CLOCK_SOURCE_IS_CONTINUOUS,
|
|
};
|
|
|
|
static int __init imx_clocksource_init(void)
|
|
{
|
|
clocksource_imx.mult =
|
|
clocksource_hz2mult(imx_get_perclk1(), clocksource_imx.shift);
|
|
clocksource_register(&clocksource_imx);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static void __init imx_timer_init(void)
|
|
{
|
|
imx_timer_hardware_init();
|
|
imx_clocksource_init();
|
|
|
|
/*
|
|
* Make irqs happen for the system timer
|
|
*/
|
|
setup_irq(TIM1_INT, &imx_timer_irq);
|
|
}
|
|
|
|
struct sys_timer imx_timer = {
|
|
.init = imx_timer_init,
|
|
};
|