Logo Search packages:      
Sourcecode: linux version File versions  Download package

time.c

/*
 * linux/arch/arm/mach-nuc93x/time.c
 *
 * Copyright (c) 2009 Nuvoton technology corporation.
 *
 * Wan ZongShun <mcuos.com@gmail.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.
 *
 */

#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/err.h>
#include <linux/clk.h>
#include <linux/io.h>
#include <linux/leds.h>

#include <asm/mach-types.h>
#include <asm/mach/irq.h>
#include <asm/mach/time.h>

#include <mach/system.h>
#include <mach/map.h>
#include <mach/regs-timer.h>

#define RESETINT  0x01
#define PERIOD          (0x01 << 27)
#define ONESHOT         (0x00 << 27)
#define COUNTEN         (0x01 << 30)
#define INTEN           (0x01 << 29)

#define TICKS_PER_SEC   100
#define PRESCALE  0x63 /* Divider = prescale + 1 */

unsigned int timer0_load;

static unsigned long nuc93x_gettimeoffset(void)
{
      return 0;
}

/*IRQ handler for the timer*/

static irqreturn_t nuc93x_timer_interrupt(int irq, void *dev_id)
{
      timer_tick();
      __raw_writel(0x01, REG_TISR); /* clear TIF0 */
      return IRQ_HANDLED;
}

static struct irqaction nuc93x_timer_irq = {
      .name       = "nuc93x Timer Tick",
      .flags            = IRQF_DISABLED | IRQF_TIMER | IRQF_IRQPOLL,
      .handler    = nuc93x_timer_interrupt,
};

/*Set up timer reg.*/

static void nuc93x_timer_setup(void)
{
      struct clk *ck_ext = clk_get(NULL, "ext");
      struct clk *ck_timer = clk_get(NULL, "timer");
      unsigned int rate, val = 0;

      BUG_ON(IS_ERR(ck_ext) || IS_ERR(ck_timer));

      clk_enable(ck_timer);
      rate = clk_get_rate(ck_ext);
      clk_put(ck_ext);
      rate = rate / (PRESCALE + 0x01);

       /* set a known state */
      __raw_writel(0x00, REG_TCSR0);
      __raw_writel(RESETINT, REG_TISR);

      timer0_load = (rate / TICKS_PER_SEC);
      __raw_writel(timer0_load, REG_TICR0);

      val |= (PERIOD | COUNTEN | INTEN | PRESCALE);;
      __raw_writel(val, REG_TCSR0);

}

static void __init nuc93x_timer_init(void)
{
      nuc93x_timer_setup();
      setup_irq(IRQ_TIMER0, &nuc93x_timer_irq);
}

struct sys_timer nuc93x_timer = {
      .init       = nuc93x_timer_init,
      .offset           = nuc93x_gettimeoffset,
      .resume           = nuc93x_timer_setup
};

Generated by  Doxygen 1.6.0   Back to index