linux/arch/arm/mach-omap2/timer-gp.c

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/*
* linux/arch/arm/mach-omap2/timer-gp.c
*
* OMAP2 GP timer support.
*
* Copyright (C) 2005 Nokia Corporation
* Author: Paul Mundt <paul.mundt@nokia.com>
* Juha Yrj<EFBFBD>l<EFBFBD> <juha.yrjola@nokia.com>
* OMAP Dual-mode timer framework support by Timo Teras
*
* Some parts based off of TI's 24xx code:
*
* Copyright (C) 2004 Texas Instruments, Inc.
*
* Roughly modelled after the OMAP1 MPU timer code.
*
* This file is subject to the terms and conditions of the GNU General Public
* License. See the file "COPYING" in the main directory of this archive
* for more details.
*/
#include <linux/init.h>
#include <linux/time.h>
#include <linux/interrupt.h>
#include <linux/err.h>
#include <linux/clk.h>
#include <linux/delay.h>
#include <asm/mach/time.h>
#include <asm/arch/dmtimer.h>
static struct omap_dm_timer *gptimer;
static inline void omap2_gp_timer_start(unsigned long load_val)
{
omap_dm_timer_set_load(gptimer, 1, 0xffffffff - load_val);
omap_dm_timer_set_int_enable(gptimer, OMAP_TIMER_INT_OVERFLOW);
omap_dm_timer_start(gptimer);
}
static irqreturn_t omap2_gp_timer_interrupt(int irq, void *dev_id,
struct pt_regs *regs)
{
write_seqlock(&xtime_lock);
omap_dm_timer_write_status(gptimer, OMAP_TIMER_INT_OVERFLOW);
timer_tick(regs);
write_sequnlock(&xtime_lock);
return IRQ_HANDLED;
}
static struct irqaction omap2_gp_timer_irq = {
.name = "gp timer",
.flags = SA_INTERRUPT | SA_TIMER,
.handler = omap2_gp_timer_interrupt,
};
static void __init omap2_gp_timer_init(void)
{
u32 tick_period;
omap_dm_timer_init();
gptimer = omap_dm_timer_request_specific(2);
BUG_ON(gptimer == NULL);
omap_dm_timer_set_source(gptimer, OMAP_TIMER_SRC_SYS_CLK);
tick_period = clk_get_rate(omap_dm_timer_get_fclk(gptimer)) / 100;
tick_period -= 1;
setup_irq(omap_dm_timer_get_irq(gptimer), &omap2_gp_timer_irq);
omap2_gp_timer_start(tick_period);
}
struct sys_timer omap_timer = {
.init = omap2_gp_timer_init,
};