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 void gt641xx_timer0_set_mode(enum clock_event_mode mode,
  68                                     struct clock_event_device *evt)
  69 {
  70         u32 ctrl;
  71
  72         raw_spin_lock(&gt641xx_timer_lock);
  73
  74         ctrl = GT_READ(GT_TC_CONTROL_OFS);
  75         ctrl &= ~(GT_TC_CONTROL_ENTC0_MSK | GT_TC_CONTROL_SELTC0_MSK);
  76
  77         switch (mode) {
  78         case CLOCK_EVT_MODE_PERIODIC:
  79                 ctrl |= GT_TC_CONTROL_ENTC0_MSK | GT_TC_CONTROL_SELTC0_MSK;
  80                 break;
  81         case CLOCK_EVT_MODE_ONESHOT:
  82                 ctrl |= GT_TC_CONTROL_ENTC0_MSK;
  83                 break;
  84         default:
  85                 break;
  86         }
  87
  88         GT_WRITE(GT_TC_CONTROL_OFS, ctrl);
  89
  90         raw_spin_unlock(&gt641xx_timer_lock);
  91 }
  92
  93 static void gt641xx_timer0_event_handler(struct clock_event_device *dev)
  94 {
  95 }
  96
  97 static struct clock_event_device gt641xx_timer0_clockevent = {
  98         .name           = "gt641xx-timer0",
  99         .features       = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT,
 100         .irq            = GT641XX_TIMER0_IRQ,
 101         .set_next_event = gt641xx_timer0_set_next_event,
 102         .set_mode       = gt641xx_timer0_set_mode,
 103         .event_handler  = gt641xx_timer0_event_handler,
 104 };
 105
 106 static irqreturn_t gt641xx_timer0_interrupt(int irq, void *dev_id)
 107 {
 108         struct clock_event_device *cd = &gt641xx_timer0_clockevent;
 109
 110         cd->event_handler(cd);
 111
 112         return IRQ_HANDLED;
 113 }
 114
 115 static struct irqaction gt641xx_timer0_irqaction = {
 116         .handler        = gt641xx_timer0_interrupt,
 117         .flags          = IRQF_PERCPU | IRQF_TIMER,
 118         .name           = "gt641xx_timer0",
 119 };
 120
 121 static int __init gt641xx_timer0_clockevent_init(void)
 122 {
 123         struct clock_event_device *cd;
 124
 125         if (!gt641xx_base_clock)
 126                 return 0;
 127
 128         GT_WRITE(GT_TC0_OFS, gt641xx_base_clock / HZ);
 129
 130         cd = &gt641xx_timer0_clockevent;
 131         cd->rating = 200 + gt641xx_base_clock / 10000000;
 132         clockevent_set_clock(cd, gt641xx_base_clock);
 133         cd->max_delta_ns = clockevent_delta2ns(0x7fffffff, cd);
 134         cd->min_delta_ns = clockevent_delta2ns(0x300, cd);
 135         cd->cpumask = cpumask_of(0);
 136
 137         clockevents_register_device(&gt641xx_timer0_clockevent);
 138
 139         return setup_irq(GT641XX_TIMER0_IRQ, &gt641xx_timer0_irqaction);
 140 }
 141 arch_initcall(gt641xx_timer0_clockevent_init);