text: /*
   * linux/arch/arm/mach-w90x900/time.c
   *
   * Based on linux/arch/arm/plat-s3c24xx/time.c by Ben Dooks
   *
   * Copyright (c) 2009 Nuvoton technology corporation
   * All rights reserved.
   *
   * 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 <linux/clocksource.h>
  #include <linux/clockchips.h>
  
  #include <asm/mach-types.h>
  #include <asm/mach/irq.h>
  #include <asm/mach/time.h>
  
  #include <mach/map.h>
  #include "regs-timer.h"
  
  #include "nuc9xx.h"
  
  #define RESETINT	0x1f
  #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 */
  
  #define	TDR_SHIFT	24
  
  static unsigned int timer0_load;
  
  static int nuc900_clockevent_shutdown(struct clock_event_device *evt)
  {
  	unsigned int val = __raw_readl(REG_TCSR0) & ~(0x03 << 27);
  
  	__raw_writel(val, REG_TCSR0);
  	return 0;
  }
  
  static int nuc900_clockevent_set_oneshot(struct clock_event_device *evt)
  {
  	unsigned int val = __raw_readl(REG_TCSR0) & ~(0x03 << 27);
  
  	val |= (ONESHOT | COUNTEN | INTEN | PRESCALE);
  
  	__raw_writel(val, REG_TCSR0);
  	return 0;
  }
  
  static int nuc900_clockevent_set_periodic(struct clock_event_device *evt)
  {
  	unsigned int val = __raw_readl(REG_TCSR0) & ~(0x03 << 27);
  
  	__raw_writel(timer0_load, REG_TICR0);
  	val |= (PERIOD | COUNTEN | INTEN | PRESCALE);
  	__raw_writel(val, REG_TCSR0);
  	return 0;
  }
  
  static int nuc900_clockevent_setnextevent(unsigned long evt,
  		struct clock_event_device *clk)
  {
  	unsigned int val;
  
  	__raw_writel(evt, REG_TICR0);
  
  	val = __raw_readl(REG_TCSR0);
  	val |= (COUNTEN | INTEN | PRESCALE);
  	__raw_writel(val, REG_TCSR0);
  
  	return 0;
  }
  
  static struct clock_event_device nuc900_clockevent_device = {
  	.name			= "nuc900-timer0",
  	.features		= CLOCK_EVT_FEAT_PERIODIC |
  				  CLOCK_EVT_FEAT_ONESHOT,
  	.set_state_shutdown	= nuc900_clockevent_shutdown,
  	.set_state_periodic	= nuc900_clockevent_set_periodic,
  	.set_state_oneshot	= nuc900_clockevent_set_oneshot,
  	.tick_resume		= nuc900_clockevent_shutdown,
  	.set_next_event		= nuc900_clockevent_setnextevent,
  	.rating			= 300,
  };
  
  /*IRQ handler for the timer*/
  
  static irqreturn_t nuc900_timer0_interrupt(int irq, void *dev_id)
  {
  	struct clock_event_device *evt = &nuc900_clockevent_device;
  
  	__raw_writel(0x01, REG_TISR); /* clear TIF0 */
  
  	evt->event_handler(evt);
  	return IRQ_HANDLED;
  }
  
  static struct irqaction nuc900_timer0_irq = {
  	.name		= "nuc900-timer0",
  	.flags		= IRQF_TIMER | IRQF_IRQPOLL,
  	.handler	= nuc900_timer0_interrupt,
  };
  
  static void __init nuc900_clockevents_init(void)
  {
  	unsigned int rate;
  	struct clk *clk = clk_get(NULL, "timer0");
  
  	BUG_ON(IS_ERR(clk));
  
  	__raw_writel(0x00, REG_TCSR0);
  
  	clk_enable(clk);
  	rate = clk_get_rate(clk) / (PRESCALE + 1);
  
  	timer0_load = (rate / TICKS_PER_SEC);
  
  	__raw_writel(RESETINT, REG_TISR);
  	setup_irq(IRQ_TIMER0, &nuc900_timer0_irq);
  
  	nuc900_clockevent_device.cpumask = cpumask_of(0);
  
  	clockevents_config_and_register(&nuc900_clockevent_device, rate,
  					0xf, 0xffffffff);
  }
  
  static void __init nuc900_clocksource_init(void)
  {
  	unsigned int val;
  	unsigned int rate;
  	struct clk *clk = clk_get(NULL, "timer1");
  
  	BUG_ON(IS_ERR(clk));
  
  	__raw_writel(0x00, REG_TCSR1);
  
  	clk_enable(clk);
  	rate = clk_get_rate(clk) / (PRESCALE + 1);
  
  	__raw_writel(0xffffffff, REG_TICR1);
  
  	val = __raw_readl(REG_TCSR1);
  	val |= (COUNTEN | PERIOD | PRESCALE);
  	__raw_writel(val, REG_TCSR1);
  
  	clocksource_mmio_init(REG_TDR1, "nuc900-timer1", rate, 200,
  		TDR_SHIFT, clocksource_mmio_readl_down);
  }
  
  void __init nuc900_timer_init(void)
  {
  	nuc900_clocksource_init();
  	nuc900_clockevents_init();
  }
  