time.c
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/*
* 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 <linux/clockchips.h>
#include <asm/mach/time.h>
#include <asm/system_misc.h>
#include <mach/regs-irq.h>
#include "generic.h"
#define KS8695_TMR_OFFSET (0xF0000 + 0xE400)
#define KS8695_TMR_VA (KS8695_IO_VA + KS8695_TMR_OFFSET)
#define KS8695_TMR_PA (KS8695_IO_PA + KS8695_TMR_OFFSET)
/*
* Timer registers
*/
#define KS8695_TMCON (0x00) /* Timer Control Register */
#define KS8695_T1TC (0x04) /* Timer 1 Timeout Count Register */
#define KS8695_T0TC (0x08) /* Timer 0 Timeout Count Register */
#define KS8695_T1PD (0x0C) /* Timer 1 Pulse Count Register */
#define KS8695_T0PD (0x10) /* Timer 0 Pulse Count Register */
/* Timer Control Register */
#define TMCON_T1EN (1 << 1) /* Timer 1 Enable */
#define TMCON_T0EN (1 << 0) /* Timer 0 Enable */
/* Timer0 Timeout Counter Register */
#define T0TC_WATCHDOG (0xff) /* Enable watchdog mode */
static void ks8695_set_mode(enum clock_event_mode mode,
struct clock_event_device *evt)
{
u32 tmcon;
if (mode == CLOCK_EVT_FEAT_PERIODIC) {
u32 rate = DIV_ROUND_CLOSEST(KS8695_CLOCK_RATE, HZ);
u32 half = DIV_ROUND_CLOSEST(rate, 2);
/* Disable timer 1 */
tmcon = readl_relaxed(KS8695_TMR_VA + KS8695_TMCON);
tmcon &= ~TMCON_T1EN;
writel_relaxed(tmcon, KS8695_TMR_VA + KS8695_TMCON);
/* Both registers need to count down */
writel_relaxed(half, KS8695_TMR_VA + KS8695_T1TC);
writel_relaxed(half, KS8695_TMR_VA + KS8695_T1PD);
/* Re-enable timer1 */
tmcon |= TMCON_T1EN;
writel_relaxed(tmcon, KS8695_TMR_VA + KS8695_TMCON);
}
}
static int ks8695_set_next_event(unsigned long cycles,
struct clock_event_device *evt)
{
u32 half = DIV_ROUND_CLOSEST(cycles, 2);
u32 tmcon;
/* Disable timer 1 */
tmcon = readl_relaxed(KS8695_TMR_VA + KS8695_TMCON);
tmcon &= ~TMCON_T1EN;
writel_relaxed(tmcon, KS8695_TMR_VA + KS8695_TMCON);
/* Both registers need to count down */
writel_relaxed(half, KS8695_TMR_VA + KS8695_T1TC);
writel_relaxed(half, KS8695_TMR_VA + KS8695_T1PD);
/* Re-enable timer1 */
tmcon |= TMCON_T1EN;
writel_relaxed(tmcon, KS8695_TMR_VA + KS8695_TMCON);
return 0;
}
static struct clock_event_device clockevent_ks8695 = {
.name = "ks8695_t1tc",
.rating = 300, /* Reasonably fast and accurate clock event */
.features = CLOCK_EVT_FEAT_ONESHOT | CLOCK_EVT_FEAT_PERIODIC,
.set_next_event = ks8695_set_next_event,
.set_mode = ks8695_set_mode,
};
/*
* IRQ handler for the timer.
*/
static irqreturn_t ks8695_timer_interrupt(int irq, void *dev_id)
{
struct clock_event_device *evt = &clockevent_ks8695;
evt->event_handler(evt);
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 tmcon;
/* Disable timer 0 and 1 */
tmcon = readl_relaxed(KS8695_TMR_VA + KS8695_TMCON);
tmcon &= ~TMCON_T0EN;
tmcon &= ~TMCON_T1EN;
writel_relaxed(tmcon, KS8695_TMR_VA + KS8695_TMCON);
/*
* Use timer 1 to fire IRQs on the timeline, minimum 2 cycles
* (one on each counter) maximum 2*2^32, but the API will only
* accept up to a 32bit full word (0xFFFFFFFFU).
*/
clockevents_config_and_register(&clockevent_ks8695,
KS8695_CLOCK_RATE, 2,
0xFFFFFFFFU);
}
void __init ks8695_timer_init(void)
{
ks8695_timer_setup();
/* Enable timer interrupts */
setup_irq(KS8695_IRQ_TIMER1, &ks8695_timer_irq);
}
void ks8695_restart(enum reboot_mode reboot_mode, const char *cmd)
{
unsigned int reg;
if (reboot_mode == REBOOT_SOFT)
soft_restart(0);
/* disable timer0 */
reg = readl_relaxed(KS8695_TMR_VA + KS8695_TMCON);
writel_relaxed(reg & ~TMCON_T0EN, KS8695_TMR_VA + KS8695_TMCON);
/* enable watchdog mode */
writel_relaxed((10 << 8) | T0TC_WATCHDOG, KS8695_TMR_VA + KS8695_T0TC);
/* re-enable timer0 */
writel_relaxed(reg | TMCON_T0EN, KS8695_TMR_VA + KS8695_TMCON);
}