linux/arch/arm/mach-w90x900/time.c
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   1/*
   2 * linux/arch/arm/mach-w90x900/time.c
   3 *
   4 * Based on linux/arch/arm/plat-s3c24xx/time.c by Ben Dooks
   5 *
   6 * Copyright (c) 2009 Nuvoton technology corporation
   7 * All rights reserved.
   8 *
   9 * Wan ZongShun <mcuos.com@gmail.com>
  10 *
  11 * This program is free software; you can redistribute it and/or modify
  12 * it under the terms of the GNU General Public License as published by
  13 * the Free Software Foundation; either version 2 of the License, or
  14 * (at your option) any later version.
  15 *
  16 */
  17
  18#include <linux/kernel.h>
  19#include <linux/sched.h>
  20#include <linux/init.h>
  21#include <linux/interrupt.h>
  22#include <linux/err.h>
  23#include <linux/clk.h>
  24#include <linux/io.h>
  25#include <linux/leds.h>
  26#include <linux/clocksource.h>
  27#include <linux/clockchips.h>
  28
  29#include <asm/mach-types.h>
  30#include <asm/mach/irq.h>
  31#include <asm/mach/time.h>
  32
  33#include <mach/map.h>
  34#include "regs-timer.h"
  35
  36#include "nuc9xx.h"
  37
  38#define RESETINT        0x1f
  39#define PERIOD          (0x01 << 27)
  40#define ONESHOT         (0x00 << 27)
  41#define COUNTEN         (0x01 << 30)
  42#define INTEN           (0x01 << 29)
  43
  44#define TICKS_PER_SEC   100
  45#define PRESCALE        0x63 /* Divider = prescale + 1 */
  46
  47#define TDR_SHIFT       24
  48
  49static unsigned int timer0_load;
  50
  51static int nuc900_clockevent_shutdown(struct clock_event_device *evt)
  52{
  53        unsigned int val = __raw_readl(REG_TCSR0) & ~(0x03 << 27);
  54
  55        __raw_writel(val, REG_TCSR0);
  56        return 0;
  57}
  58
  59static int nuc900_clockevent_set_oneshot(struct clock_event_device *evt)
  60{
  61        unsigned int val = __raw_readl(REG_TCSR0) & ~(0x03 << 27);
  62
  63        val |= (ONESHOT | COUNTEN | INTEN | PRESCALE);
  64
  65        __raw_writel(val, REG_TCSR0);
  66        return 0;
  67}
  68
  69static int nuc900_clockevent_set_periodic(struct clock_event_device *evt)
  70{
  71        unsigned int val = __raw_readl(REG_TCSR0) & ~(0x03 << 27);
  72
  73        __raw_writel(timer0_load, REG_TICR0);
  74        val |= (PERIOD | COUNTEN | INTEN | PRESCALE);
  75        __raw_writel(val, REG_TCSR0);
  76        return 0;
  77}
  78
  79static int nuc900_clockevent_setnextevent(unsigned long evt,
  80                struct clock_event_device *clk)
  81{
  82        unsigned int val;
  83
  84        __raw_writel(evt, REG_TICR0);
  85
  86        val = __raw_readl(REG_TCSR0);
  87        val |= (COUNTEN | INTEN | PRESCALE);
  88        __raw_writel(val, REG_TCSR0);
  89
  90        return 0;
  91}
  92
  93static struct clock_event_device nuc900_clockevent_device = {
  94        .name                   = "nuc900-timer0",
  95        .features               = CLOCK_EVT_FEAT_PERIODIC |
  96                                  CLOCK_EVT_FEAT_ONESHOT,
  97        .set_state_shutdown     = nuc900_clockevent_shutdown,
  98        .set_state_periodic     = nuc900_clockevent_set_periodic,
  99        .set_state_oneshot      = nuc900_clockevent_set_oneshot,
 100        .tick_resume            = nuc900_clockevent_shutdown,
 101        .set_next_event         = nuc900_clockevent_setnextevent,
 102        .rating                 = 300,
 103};
 104
 105/*IRQ handler for the timer*/
 106
 107static irqreturn_t nuc900_timer0_interrupt(int irq, void *dev_id)
 108{
 109        struct clock_event_device *evt = &nuc900_clockevent_device;
 110
 111        __raw_writel(0x01, REG_TISR); /* clear TIF0 */
 112
 113        evt->event_handler(evt);
 114        return IRQ_HANDLED;
 115}
 116
 117static struct irqaction nuc900_timer0_irq = {
 118        .name           = "nuc900-timer0",
 119        .flags          = IRQF_TIMER | IRQF_IRQPOLL,
 120        .handler        = nuc900_timer0_interrupt,
 121};
 122
 123static void __init nuc900_clockevents_init(void)
 124{
 125        unsigned int rate;
 126        struct clk *clk = clk_get(NULL, "timer0");
 127
 128        BUG_ON(IS_ERR(clk));
 129
 130        __raw_writel(0x00, REG_TCSR0);
 131
 132        clk_enable(clk);
 133        rate = clk_get_rate(clk) / (PRESCALE + 1);
 134
 135        timer0_load = (rate / TICKS_PER_SEC);
 136
 137        __raw_writel(RESETINT, REG_TISR);
 138        setup_irq(IRQ_TIMER0, &nuc900_timer0_irq);
 139
 140        nuc900_clockevent_device.cpumask = cpumask_of(0);
 141
 142        clockevents_config_and_register(&nuc900_clockevent_device, rate,
 143                                        0xf, 0xffffffff);
 144}
 145
 146static void __init nuc900_clocksource_init(void)
 147{
 148        unsigned int val;
 149        unsigned int rate;
 150        struct clk *clk = clk_get(NULL, "timer1");
 151
 152        BUG_ON(IS_ERR(clk));
 153
 154        __raw_writel(0x00, REG_TCSR1);
 155
 156        clk_enable(clk);
 157        rate = clk_get_rate(clk) / (PRESCALE + 1);
 158
 159        __raw_writel(0xffffffff, REG_TICR1);
 160
 161        val = __raw_readl(REG_TCSR1);
 162        val |= (COUNTEN | PERIOD | PRESCALE);
 163        __raw_writel(val, REG_TCSR1);
 164
 165        clocksource_mmio_init(REG_TDR1, "nuc900-timer1", rate, 200,
 166                TDR_SHIFT, clocksource_mmio_readl_down);
 167}
 168
 169void __init nuc900_timer_init(void)
 170{
 171        nuc900_clocksource_init();
 172        nuc900_clockevents_init();
 173}
 174