- 根目录:
- arch
- arm
- mach-omap1
- timer32k.c
/*
* linux/arch/arm/mach-omap1/timer32k.c
*
* OMAP 32K Timer
*
* Copyright (C) 2004 - 2005 Nokia Corporation
* Partial timer rewrite and additional dynamic tick timer support by
* Tony Lindgen <tony@atomide.com> and
* Tuukka Tikkanen <tuukka.tikkanen@elektrobit.com>
* OMAP Dual-mode timer framework support by Timo Teras
*
* MPU timer code based on the older MPU timer code for OMAP
* Copyright (C) 2000 RidgeRun, Inc.
* Author: Greg Lonnon <glonnon@ridgerun.com>
*
* 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 SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED
* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN
* NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
* USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
* ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
* 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.,
* 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/delay.h>
#include <linux/interrupt.h>
#include <linux/sched.h>
#include <linux/spinlock.h>
#include <linux/err.h>
#include <linux/clk.h>
#include <linux/clocksource.h>
#include <linux/clockchips.h>
#include <linux/io.h>
#include <asm/irq.h>
#include <asm/mach/irq.h>
#include <asm/mach/time.h>
#include <plat/counter-32k.h>
#include <mach/hardware.h>
#include "common.h"
/*
* ---------------------------------------------------------------------------
* 32KHz OS timer
*
* This currently works only on 16xx, as 1510 does not have the continuous
* 32KHz synchronous timer. The 32KHz synchronous timer is used to keep track
* of time in addition to the 32KHz OS timer. Using only the 32KHz OS timer
* on 1510 would be possible, but the timer would not be as accurate as
* with the 32KHz synchronized timer.
* ---------------------------------------------------------------------------
*/
/* 16xx specific defines */
#define OMAP1_32K_TIMER_BASE 0xfffb9000
#define OMAP1_32KSYNC_TIMER_BASE 0xfffbc400
#define OMAP1_32K_TIMER_CR 0x08
#define OMAP1_32K_TIMER_TVR 0x00
#define OMAP1_32K_TIMER_TCR 0x04
#define OMAP_32K_TICKS_PER_SEC (32768)
/*
* TRM says 1 / HZ = ( TVR + 1) / 32768, so TRV = (32768 / HZ) - 1
* so with HZ = 128, TVR = 255.
*/
#define OMAP_32K_TIMER_TICK_PERIOD ((OMAP_32K_TICKS_PER_SEC / HZ) - 1)
#define JIFFIES_TO_HW_TICKS(nr_jiffies, clock_rate) \
(((nr_jiffies) * (clock_rate)) / HZ)
static inline void omap_32k_timer_write(int val, int reg)
{
omap_writew(val, OMAP1_32K_TIMER_BASE + reg);
}
static inline unsigned long omap_32k_timer_read(int reg)
{
return omap_readl(OMAP1_32K_TIMER_BASE + reg) & 0xffffff;
}
static inline void omap_32k_timer_start(unsigned long load_val)
{
if (!load_val)
load_val = 1;
omap_32k_timer_write(load_val, OMAP1_32K_TIMER_TVR);
omap_32k_timer_write(0x0f, OMAP1_32K_TIMER_CR);
}
static inline void omap_32k_timer_stop(void)
{
omap_32k_timer_write(0x0, OMAP1_32K_TIMER_CR);
}
#define omap_32k_timer_ack_irq()
static int omap_32k_timer_set_next_event(unsigned long delta,
struct clock_event_device *dev)
{
omap_32k_timer_start(delta);
return 0;
}
static void omap_32k_timer_set_mode(enum clock_event_mode mode,
struct clock_event_device *evt)
{
omap_32k_timer_stop();
switch (mode) {
case CLOCK_EVT_MODE_PERIODIC:
omap_32k_timer_start(OMAP_32K_TIMER_TICK_PERIOD);
break;
case CLOCK_EVT_MODE_ONESHOT:
case CLOCK_EVT_MODE_UNUSED:
case CLOCK_EVT_MODE_SHUTDOWN:
break;
case CLOCK_EVT_MODE_RESUME:
break;
}
}
static struct clock_event_device clockevent_32k_timer = {
.name = "32k-timer",
.features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT,
.set_next_event = omap_32k_timer_set_next_event,
.set_mode = omap_32k_timer_set_mode,
};
static irqreturn_t omap_32k_timer_interrupt(int irq, void *dev_id)
{
struct clock_event_device *evt = &clockevent_32k_timer;
omap_32k_timer_ack_irq();
evt->event_handler(evt);
return IRQ_HANDLED;
}
static struct irqaction omap_32k_timer_irq = {
.name = "32KHz timer",
.flags = IRQF_DISABLED | IRQF_TIMER | IRQF_IRQPOLL,
.handler = omap_32k_timer_interrupt,
};
static __init void omap_init_32k_timer(void)
{
setup_irq(INT_OS_TIMER, &omap_32k_timer_irq);
clockevent_32k_timer.cpumask = cpumask_of(0);
clockevents_config_and_register(&clockevent_32k_timer,
OMAP_32K_TICKS_PER_SEC, 1, 0xfffffffe);
}
/*
* ---------------------------------------------------------------------------
* Timer initialization
* ---------------------------------------------------------------------------
*/
int __init omap_32k_timer_init(void)
{
int ret = -ENODEV;
if (cpu_is_omap16xx()) {
void __iomem *base;
struct clk *sync32k_ick;
base = ioremap(OMAP1_32KSYNC_TIMER_BASE, SZ_1K);
if (!base) {
pr_err("32k_counter: failed to map base addr\n");
return -ENODEV;
}
sync32k_ick = clk_get(NULL, "omap_32ksync_ick");
if (!IS_ERR(sync32k_ick))
clk_enable(sync32k_ick);
ret = omap_init_clocksource_32k(base);
}
if (!ret)
omap_init_32k_timer();
return ret;
}