arch/mips/kernel/cevt-gt641xx.c

   1 /*
   2  *  GT641xx clockevent routines.
   3  *
   4  *  Copyright (C) 2007  Yoichi Yuasa <yuasa@linux-mips.org>
   5  *
   6  *  This program is free software; you can redistribute it and/or modify
   7  *  it under the terms of the GNU General Public License as published by
   8  *  the Free Software Foundation; either version 2 of the License, or
   9  *  (at your option) any later version.
  10  *
  11  *  This program is distributed in the hope that it will be useful,
  12  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  *  GNU General Public License for more details.
  15  *
  16  *  You should have received a copy of the GNU General Public License
  17  *  along with this program; if not, write to the Free Software
  18  *  Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  19  */
  20 #include <linux/clockchips.h>
  21 #include <linux/init.h>
  22 #include <linux/interrupt.h>
  23 #include <linux/spinlock.h>
  24 #include <linux/irq.h>
  25
  26 #include <asm/gt64120.h>
  27 #include <asm/time.h>
  28
  29 static DEFINE_RAW_SPINLOCK(gt641xx_timer_lock);
  30 static unsigned int gt641xx_base_clock;
  31
  32 void gt641xx_set_base_clock(unsigned int clock)
  33 {
  34         gt641xx_base_clock = clock;
  35 }
  36
  37 int gt641xx_timer0_state(void)
  38 {
  39         if (GT_READ(GT_TC0_OFS))
  40                 return 0;
  41
  42         GT_WRITE(GT_TC0_OFS, gt641xx_base_clock / HZ);
  43         GT_WRITE(GT_TC_CONTROL_OFS, GT_TC_CONTROL_ENTC0_MSK);
  44
  45         return 1;
  46 }
  47
  48 static int gt641xx_timer0_set_next_event(unsigned long delta,
  49                                          struct clock_event_device *evt)
  50 {
  51         u32 ctrl;
  52
  53         raw_spin_lock(&gt641xx_timer_lock);
  54
  55         ctrl = GT_READ(GT_TC_CONTROL_OFS);
  56         ctrl &= ~(GT_TC_CONTROL_ENTC0_MSK | GT_TC_CONTROL_SELTC0_MSK);
  57         ctrl |= GT_TC_CONTROL_ENTC0_MSK;
  58
  59         GT_WRITE(GT_TC0_OFS, delta);
  60         GT_WRITE(GT_TC_CONTROL_OFS, ctrl);
  61
  62         raw_spin_unlock(&gt641xx_timer_lock);
  63
  64         return 0;
  65 }
  66
  67 static int gt641xx_timer0_shutdown(struct clock_event_device *evt)
  68 {
  69         u32 ctrl;
  70
  71         raw_spin_lock(&gt641xx_timer_lock);
  72
  73         ctrl = GT_READ(GT_TC_CONTROL_OFS);
  74         ctrl &= ~(GT_TC_CONTROL_ENTC0_MSK | GT_TC_CONTROL_SELTC0_MSK);
  75         GT_WRITE(GT_TC_CONTROL_OFS, ctrl);
  76
  77         raw_spin_unlock(&gt641xx_timer_lock);
  78         return 0;
  79 }
  80
  81 static int gt641xx_timer0_set_oneshot(struct clock_event_device *evt)
  82 {
  83         u32 ctrl;
  84
  85         raw_spin_lock(&gt641xx_timer_lock);
  86
  87         ctrl = GT_READ(GT_TC_CONTROL_OFS);
  88         ctrl &= ~GT_TC_CONTROL_SELTC0_MSK;
  89         ctrl |= GT_TC_CONTROL_ENTC0_MSK;
  90         GT_WRITE(GT_TC_CONTROL_OFS, ctrl);
  91
  92         raw_spin_unlock(&gt641xx_timer_lock);
  93         return 0;
  94 }
  95
  96 static int gt641xx_timer0_set_periodic(struct clock_event_device *evt)
  97 {
  98         u32 ctrl;
  99
 100         raw_spin_lock(&gt641xx_timer_lock);
 101
 102         ctrl = GT_READ(GT_TC_CONTROL_OFS);
 103         ctrl |= GT_TC_CONTROL_ENTC0_MSK | GT_TC_CONTROL_SELTC0_MSK;
 104         GT_WRITE(GT_TC_CONTROL_OFS, ctrl);
 105
 106         raw_spin_unlock(&gt641xx_timer_lock);
 107         return 0;
 108 }
 109
 110 static void gt641xx_timer0_event_handler(struct clock_event_device *dev)
 111 {
 112 }
 113
 114 static struct clock_event_device gt641xx_timer0_clockevent = {
 115         .name                   = "gt641xx-timer0",
 116         .features               = CLOCK_EVT_FEAT_PERIODIC |
 117                                   CLOCK_EVT_FEAT_ONESHOT,
 118         .irq                    = GT641XX_TIMER0_IRQ,
 119         .set_next_event         = gt641xx_timer0_set_next_event,
 120         .set_state_shutdown     = gt641xx_timer0_shutdown,
 121         .set_state_periodic     = gt641xx_timer0_set_periodic,
 122         .set_state_oneshot      = gt641xx_timer0_set_oneshot,
 123         .tick_resume            = gt641xx_timer0_shutdown,
 124         .event_handler          = gt641xx_timer0_event_handler,
 125 };
 126
 127 static irqreturn_t gt641xx_timer0_interrupt(int irq, void *dev_id)
 128 {
 129         struct clock_event_device *cd = &gt641xx_timer0_clockevent;
 130
 131         cd->event_handler(cd);
 132
 133         return IRQ_HANDLED;
 134 }
 135
 136 static struct irqaction gt641xx_timer0_irqaction = {
 137         .handler        = gt641xx_timer0_interrupt,
 138         .flags          = IRQF_PERCPU | IRQF_TIMER,
 139         .name           = "gt641xx_timer0",
 140 };
 141
 142 static int __init gt641xx_timer0_clockevent_init(void)
 143 {
 144         struct clock_event_device *cd;
 145
 146         if (!gt641xx_base_clock)
 147                 return 0;
 148
 149         GT_WRITE(GT_TC0_OFS, gt641xx_base_clock / HZ);
 150
 151         cd = &gt641xx_timer0_clockevent;
 152         cd->rating = 200 + gt641xx_base_clock / 10000000;
 153         clockevent_set_clock(cd, gt641xx_base_clock);
 154         cd->max_delta_ns = clockevent_delta2ns(0x7fffffff, cd);
 155         cd->max_delta_ticks = 0x7fffffff;
 156         cd->min_delta_ns = clockevent_delta2ns(0x300, cd);
 157         cd->min_delta_ticks = 0x300;
 158         cd->cpumask = cpumask_of(0);
 159
 160         clockevents_register_device(&gt641xx_timer0_clockevent);
 161
 162         return setup_irq(GT641XX_TIMER0_IRQ, &gt641xx_timer0_irqaction);
 163 }
 164 arch_initcall(gt641xx_timer0_clockevent_init);