arch/arm/mach-w90x900/time.c

   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 <mach/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
  49 static unsigned int timer0_load;
  50
  51 static 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
  59 static 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
  69 static 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
  79 static 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
  93 static 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
 107 static 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
 117 static struct irqaction nuc900_timer0_irq = {
 118         .name           = "nuc900-timer0",
 119         .flags          = IRQF_TIMER | IRQF_IRQPOLL,
 120         .handler        = nuc900_timer0_interrupt,
 121 };
 122
 123 static 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
 146 static 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
 169 void __init nuc900_timer_init(void)
 170 {
 171         nuc900_clocksource_init();
 172         nuc900_clockevents_init();
 173 }