release/src-rt-6.x.4708/linux/linux-2.6.36/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 #define RESETINT        0x1f
  37 #define PERIOD          (0x01 << 27)
  38 #define ONESHOT         (0x00 << 27)
  39 #define COUNTEN         (0x01 << 30)
  40 #define INTEN           (0x01 << 29)
  41
  42 #define TICKS_PER_SEC   100
  43 #define PRESCALE        0x63 /* Divider = prescale + 1 */
  44
  45 #define TDR_SHIFT       24
  46 #define TDR_MASK        ((1 << TDR_SHIFT) - 1)
  47
  48 static unsigned int timer0_load;
  49
  50 static void nuc900_clockevent_setmode(enum clock_event_mode mode,
  51                 struct clock_event_device *clk)
  52 {
  53         unsigned int val;
  54
  55         val = __raw_readl(REG_TCSR0);
  56         val &= ~(0x03 << 27);
  57
  58         switch (mode) {
  59         case CLOCK_EVT_MODE_PERIODIC:
  60                 __raw_writel(timer0_load, REG_TICR0);
  61                 val |= (PERIOD | COUNTEN | INTEN | PRESCALE);
  62                 break;
  63
  64         case CLOCK_EVT_MODE_ONESHOT:
  65                 val |= (ONESHOT | COUNTEN | INTEN | PRESCALE);
  66                 break;
  67
  68         case CLOCK_EVT_MODE_UNUSED:
  69         case CLOCK_EVT_MODE_SHUTDOWN:
  70         case CLOCK_EVT_MODE_RESUME:
  71                 break;
  72         }
  73
  74         __raw_writel(val, REG_TCSR0);
  75 }
  76
  77 static int nuc900_clockevent_setnextevent(unsigned long evt,
  78                 struct clock_event_device *clk)
  79 {
  80         unsigned int val;
  81
  82         __raw_writel(evt, REG_TICR0);
  83
  84         val = __raw_readl(REG_TCSR0);
  85         val |= (COUNTEN | INTEN | PRESCALE);
  86         __raw_writel(val, REG_TCSR0);
  87
  88         return 0;
  89 }
  90
  91 static struct clock_event_device nuc900_clockevent_device = {
  92         .name           = "nuc900-timer0",
  93         .shift          = 32,
  94         .features       = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT,
  95         .set_mode       = nuc900_clockevent_setmode,
  96         .set_next_event = nuc900_clockevent_setnextevent,
  97         .rating         = 300,
  98 };
  99
 100 /*IRQ handler for the timer*/
 101
 102 static irqreturn_t nuc900_timer0_interrupt(int irq, void *dev_id)
 103 {
 104         struct clock_event_device *evt = &nuc900_clockevent_device;
 105
 106         __raw_writel(0x01, REG_TISR); /* clear TIF0 */
 107
 108         evt->event_handler(evt);
 109         return IRQ_HANDLED;
 110 }
 111
 112 static struct irqaction nuc900_timer0_irq = {
 113         .name           = "nuc900-timer0",
 114         .flags          = IRQF_DISABLED | IRQF_TIMER | IRQF_IRQPOLL,
 115         .handler        = nuc900_timer0_interrupt,
 116 };
 117
 118 static void __init nuc900_clockevents_init(void)
 119 {
 120         unsigned int rate;
 121         struct clk *clk = clk_get(NULL, "timer0");
 122
 123         BUG_ON(IS_ERR(clk));
 124
 125         __raw_writel(0x00, REG_TCSR0);
 126
 127         clk_enable(clk);
 128         rate = clk_get_rate(clk) / (PRESCALE + 1);
 129
 130         timer0_load = (rate / TICKS_PER_SEC);
 131
 132         __raw_writel(RESETINT, REG_TISR);
 133         setup_irq(IRQ_TIMER0, &nuc900_timer0_irq);
 134
 135         nuc900_clockevent_device.mult = div_sc(rate, NSEC_PER_SEC,
 136                                         nuc900_clockevent_device.shift);
 137         nuc900_clockevent_device.max_delta_ns = clockevent_delta2ns(0xffffffff,
 138                                         &nuc900_clockevent_device);
 139         nuc900_clockevent_device.min_delta_ns = clockevent_delta2ns(0xf,
 140                                         &nuc900_clockevent_device);
 141         nuc900_clockevent_device.cpumask = cpumask_of(0);
 142
 143         clockevents_register_device(&nuc900_clockevent_device);
 144 }
 145
 146 static cycle_t nuc900_get_cycles(struct clocksource *cs)
 147 {
 148         return (~__raw_readl(REG_TDR1)) & TDR_MASK;
 149 }
 150
 151 static struct clocksource clocksource_nuc900 = {
 152         .name   = "nuc900-timer1",
 153         .rating = 200,
 154         .read   = nuc900_get_cycles,
 155         .mask   = CLOCKSOURCE_MASK(TDR_SHIFT),
 156         .shift  = 10,
 157         .flags  = CLOCK_SOURCE_IS_CONTINUOUS,
 158 };
 159
 160 static void __init nuc900_clocksource_init(void)
 161 {
 162         unsigned int val;
 163         unsigned int rate;
 164         struct clk *clk = clk_get(NULL, "timer1");
 165
 166         BUG_ON(IS_ERR(clk));
 167
 168         __raw_writel(0x00, REG_TCSR1);
 169
 170         clk_enable(clk);
 171         rate = clk_get_rate(clk) / (PRESCALE + 1);
 172
 173         __raw_writel(0xffffffff, REG_TICR1);
 174
 175         val = __raw_readl(REG_TCSR1);
 176         val |= (COUNTEN | PERIOD | PRESCALE);
 177         __raw_writel(val, REG_TCSR1);
 178
 179         clocksource_nuc900.mult =
 180                 clocksource_khz2mult((rate / 1000), clocksource_nuc900.shift);
 181         clocksource_register(&clocksource_nuc900);
 182 }
 183
 184 static void __init nuc900_timer_init(void)
 185 {
 186         nuc900_clocksource_init();
 187         nuc900_clockevents_init();
 188 }
 189
 190 struct sys_timer nuc900_timer = {
 191         .init           = nuc900_timer_init,
 192 };