time.c
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/*
* arch/arm/mach-netx/time.c
*
* Copyright (c) 2005 Sascha Hauer <s.hauer@pengutronix.de>, Pengutronix
*
* 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.
*
* 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/clocksource.h>
#include <linux/clockchips.h>
#include <linux/io.h>
#include <mach/hardware.h>
#include <asm/mach/time.h>
#include <mach/netx-regs.h>
#define TIMER_CLOCKEVENT 0
#define TIMER_CLOCKSOURCE 1
static void netx_set_mode(enum clock_event_mode mode,
struct clock_event_device *clk)
{
u32 tmode;
/* disable timer */
writel(0, NETX_GPIO_COUNTER_CTRL(TIMER_CLOCKEVENT));
switch (mode) {
case CLOCK_EVT_MODE_PERIODIC:
writel(LATCH, NETX_GPIO_COUNTER_MAX(TIMER_CLOCKEVENT));
tmode = NETX_GPIO_COUNTER_CTRL_RST_EN |
NETX_GPIO_COUNTER_CTRL_IRQ_EN |
NETX_GPIO_COUNTER_CTRL_RUN;
break;
case CLOCK_EVT_MODE_ONESHOT:
writel(0, NETX_GPIO_COUNTER_MAX(TIMER_CLOCKEVENT));
tmode = NETX_GPIO_COUNTER_CTRL_IRQ_EN |
NETX_GPIO_COUNTER_CTRL_RUN;
break;
default:
WARN(1, "%s: unhandled mode %d\n", __func__, mode);
/* fall through */
case CLOCK_EVT_MODE_SHUTDOWN:
case CLOCK_EVT_MODE_UNUSED:
case CLOCK_EVT_MODE_RESUME:
tmode = 0;
break;
}
writel(tmode, NETX_GPIO_COUNTER_CTRL(TIMER_CLOCKEVENT));
}
static int netx_set_next_event(unsigned long evt,
struct clock_event_device *clk)
{
writel(0 - evt, NETX_GPIO_COUNTER_CURRENT(TIMER_CLOCKEVENT));
return 0;
}
static struct clock_event_device netx_clockevent = {
.name = "netx-timer" __stringify(TIMER_CLOCKEVENT),
.features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT,
.set_next_event = netx_set_next_event,
.set_mode = netx_set_mode,
};
/*
* IRQ handler for the timer
*/
static irqreturn_t
netx_timer_interrupt(int irq, void *dev_id)
{
struct clock_event_device *evt = &netx_clockevent;
/* acknowledge interrupt */
writel(COUNTER_BIT(0), NETX_GPIO_IRQ);
evt->event_handler(evt);
return IRQ_HANDLED;
}
static struct irqaction netx_timer_irq = {
.name = "NetX Timer Tick",
.flags = IRQF_DISABLED | IRQF_TIMER | IRQF_IRQPOLL,
.handler = netx_timer_interrupt,
};
/*
* Set up timer interrupt
*/
void __init netx_timer_init(void)
{
/* disable timer initially */
writel(0, NETX_GPIO_COUNTER_CTRL(0));
/* Reset the timer value to zero */
writel(0, NETX_GPIO_COUNTER_CURRENT(0));
writel(LATCH, NETX_GPIO_COUNTER_MAX(0));
/* acknowledge interrupt */
writel(COUNTER_BIT(0), NETX_GPIO_IRQ);
/* Enable the interrupt in the specific timer
* register and start timer
*/
writel(COUNTER_BIT(0), NETX_GPIO_IRQ_ENABLE);
writel(NETX_GPIO_COUNTER_CTRL_IRQ_EN | NETX_GPIO_COUNTER_CTRL_RUN,
NETX_GPIO_COUNTER_CTRL(0));
setup_irq(NETX_IRQ_TIMER0, &netx_timer_irq);
/* Setup timer one for clocksource */
writel(0, NETX_GPIO_COUNTER_CTRL(TIMER_CLOCKSOURCE));
writel(0, NETX_GPIO_COUNTER_CURRENT(TIMER_CLOCKSOURCE));
writel(0xffffffff, NETX_GPIO_COUNTER_MAX(TIMER_CLOCKSOURCE));
writel(NETX_GPIO_COUNTER_CTRL_RUN,
NETX_GPIO_COUNTER_CTRL(TIMER_CLOCKSOURCE));
clocksource_mmio_init(NETX_GPIO_COUNTER_CURRENT(TIMER_CLOCKSOURCE),
"netx_timer", CLOCK_TICK_RATE, 200, 32, clocksource_mmio_readl_up);
/* with max_delta_ns >= delta2ns(0x800) the system currently runs fine.
* Adding some safety ... */
netx_clockevent.cpumask = cpumask_of(0);
clockevents_config_and_register(&netx_clockevent, CLOCK_TICK_RATE,
0xa00, 0xfffffffe);
}