112 lines
3.2 KiB
C
112 lines
3.2 KiB
C
|
/*
|
||
|
|
* arch/arm/mach-ks8695/time.c
|
||
|
|
*
|
||
|
|
* Copyright (C) 2006 Ben Dooks <ben@simtec.co.uk>
|
||
|
|
* Copyright (C) 2006 Simtec Electronics
|
||
|
|
*
|
||
|
|
* 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/init.h>
|
||
|
|
#include <linux/interrupt.h>
|
||
|
|
#include <linux/irq.h>
|
||
|
|
#include <linux/kernel.h>
|
||
|
|
#include <linux/sched.h>
|
||
|
|
#include <linux/io.h>
|
||
|
|
|
||
|
|
#include <asm/mach/time.h>
|
||
|
|
|
||
|
|
#include <mach/regs-timer.h>
|
||
|
|
#include <mach/regs-irq.h>
|
||
|
|
|
||
|
|
#include "generic.h"
|
||
|
|
|
||
|
|
/*
|
||
|
|
* Returns number of ms since last clock interrupt. Note that interrupts
|
||
|
|
* will have been disabled by do_gettimeoffset()
|
||
|
|
*/
|
||
|
|
static unsigned long ks8695_gettimeoffset (void)
|
||
|
|
{
|
||
|
|
unsigned long elapsed, tick2, intpending;
|
||
|
|
|
||
|
|
/*
|
||
|
|
* Get the current number of ticks. Note that there is a race
|
||
|
|
* condition between us reading the timer and checking for an
|
||
|
|
* interrupt. We solve this by ensuring that the counter has not
|
||
|
|
* reloaded between our two reads.
|
||
|
|
*/
|
||
|
|
elapsed = __raw_readl(KS8695_TMR_VA + KS8695_T1TC) + __raw_readl(KS8695_TMR_VA + KS8695_T1PD);
|
||
|
|
do {
|
||
|
|
tick2 = elapsed;
|
||
|
|
intpending = __raw_readl(KS8695_IRQ_VA + KS8695_INTST) & (1 << KS8695_IRQ_TIMER1);
|
||
|
|
elapsed = __raw_readl(KS8695_TMR_VA + KS8695_T1TC) + __raw_readl(KS8695_TMR_VA + KS8695_T1PD);
|
||
|
|
} while (elapsed > tick2);
|
||
|
|
|
||
|
|
/* Convert to number of ticks expired (not remaining) */
|
||
|
|
elapsed = (CLOCK_TICK_RATE / HZ) - elapsed;
|
||
|
|
|
||
|
|
/* Is interrupt pending? If so, then timer has been reloaded already. */
|
||
|
|
if (intpending)
|
||
|
|
elapsed += (CLOCK_TICK_RATE / HZ);
|
||
|
|
|
||
|
|
/* Convert ticks to usecs */
|
||
|
|
return (unsigned long)(elapsed * (tick_nsec / 1000)) / LATCH;
|
||
|
|
}
|
||
|
|
|
||
|
|
/*
|
||
|
|
* IRQ handler for the timer.
|
||
|
|
*/
|
||
|
|
static irqreturn_t ks8695_timer_interrupt(int irq, void *dev_id)
|
||
|
|
{
|
||
|
|
timer_tick();
|
||
|
|
return IRQ_HANDLED;
|
||
|
|
}
|
||
|
|
|
||
|
|
static struct irqaction ks8695_timer_irq = {
|
||
|
|
.name = "ks8695_tick",
|
||
|
|
.flags = IRQF_DISABLED | IRQF_TIMER,
|
||
|
|
.handler = ks8695_timer_interrupt,
|
||
|
|
};
|
||
|
|
|
||
|
|
static void ks8695_timer_setup(void)
|
||
|
|
{
|
||
|
|
unsigned long tmout = CLOCK_TICK_RATE / HZ;
|
||
|
|
unsigned long tmcon;
|
||
|
|
|
||
|
|
/* disable timer1 */
|
||
|
|
tmcon = __raw_readl(KS8695_TMR_VA + KS8695_TMCON);
|
||
|
|
__raw_writel(tmcon & ~TMCON_T1EN, KS8695_TMR_VA + KS8695_TMCON);
|
||
|
|
|
||
|
|
__raw_writel(tmout / 2, KS8695_TMR_VA + KS8695_T1TC);
|
||
|
|
__raw_writel(tmout / 2, KS8695_TMR_VA + KS8695_T1PD);
|
||
|
|
|
||
|
|
/* re-enable timer1 */
|
||
|
|
__raw_writel(tmcon | TMCON_T1EN, KS8695_TMR_VA + KS8695_TMCON);
|
||
|
|
}
|
||
|
|
|
||
|
|
static void __init ks8695_timer_init (void)
|
||
|
|
{
|
||
|
|
ks8695_timer_setup();
|
||
|
|
|
||
|
|
/* Enable timer interrupts */
|
||
|
|
setup_irq(KS8695_IRQ_TIMER1, &ks8695_timer_irq);
|
||
|
|
}
|
||
|
|
|
||
|
|
struct sys_timer ks8695_timer = {
|
||
|
|
.init = ks8695_timer_init,
|
||
|
|
.offset = ks8695_gettimeoffset,
|
||
|
|
.resume = ks8695_timer_setup,
|
||
|
|
};
|