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
  25 #include <asm/gt64120.h>
  26 #include <asm/time.h>
  27
  28 static DEFINE_SPINLOCK(gt641xx_timer_lock);
  29 static unsigned int gt641xx_base_clock;
  30
  31 void gt641xx_set_base_clock(unsigned int clock)
  32 {
  33         gt641xx_base_clock = clock;
  34 }
  35
  36 int gt641xx_timer0_state(void)
  37 {
  38         if (GT_READ(GT_TC0_OFS))
  39                 return 0;
  40
  41         GT_WRITE(GT_TC0_OFS, gt641xx_base_clock / HZ);
  42         GT_WRITE(GT_TC_CONTROL_OFS, GT_TC_CONTROL_ENTC0_MSK);
  43
  44         return 1;
  45 }
  46
  47 static int gt641xx_timer0_set_next_event(unsigned long delta,
  48                                          struct clock_event_device *evt)
  49 {
  50         u32 ctrl;
  51
  52         spin_lock(&gt641xx_timer_lock);
  53
  54         ctrl = GT_READ(GT_TC_CONTROL_OFS);
  55         ctrl &= ~(GT_TC_CONTROL_ENTC0_MSK | GT_TC_CONTROL_SELTC0_MSK);
  56         ctrl |= GT_TC_CONTROL_ENTC0_MSK;
  57
  58         GT_WRITE(GT_TC0_OFS, delta);
  59         GT_WRITE(GT_TC_CONTROL_OFS, ctrl);
  60
  61         spin_unlock(&gt641xx_timer_lock);
  62
  63         return 0;
  64 }
  65
  66 static void gt641xx_timer0_set_mode(enum clock_event_mode mode,
  67                                     struct clock_event_device *evt)
  68 {
  69         u32 ctrl;
  70
  71         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
  76         switch (mode) {
  77         case CLOCK_EVT_MODE_PERIODIC:
  78                 ctrl |= GT_TC_CONTROL_ENTC0_MSK | GT_TC_CONTROL_SELTC0_MSK;
  79                 break;
  80         case CLOCK_EVT_MODE_ONESHOT:
  81                 ctrl |= GT_TC_CONTROL_ENTC0_MSK;
  82                 break;
  83         default:
  84                 break;
  85         }
  86
  87         GT_WRITE(GT_TC_CONTROL_OFS, ctrl);
  88
  89         spin_unlock(&gt641xx_timer_lock);
  90 }
  91
  92 static void gt641xx_timer0_event_handler(struct clock_event_device *dev)
  93 {
  94 }
  95
  96 static struct clock_event_device gt641xx_timer0_clockevent = {
  97         .name           = "gt641xx-timer0",
  98         .features       = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT,
  99         .irq            = GT641XX_TIMER0_IRQ,
 100         .set_next_event = gt641xx_timer0_set_next_event,
 101         .set_mode       = gt641xx_timer0_set_mode,
 102         .event_handler  = gt641xx_timer0_event_handler,
 103 };
 104
 105 static irqreturn_t gt641xx_timer0_interrupt(int irq, void *dev_id)
 106 {
 107         struct clock_event_device *cd = &gt641xx_timer0_clockevent;
 108
 109         cd->event_handler(cd);
 110
 111         return IRQ_HANDLED;
 112 }
 113
 114 static struct irqaction gt641xx_timer0_irqaction = {
 115         .handler        = gt641xx_timer0_interrupt,
 116         .flags          = IRQF_DISABLED | IRQF_PERCPU,
 117         .name           = "gt641xx_timer0",
 118 };
 119
 120 static int __init gt641xx_timer0_clockevent_init(void)
 121 {
 122         struct clock_event_device *cd;
 123
 124         if (!gt641xx_base_clock)
 125                 return 0;
 126
 127         GT_WRITE(GT_TC0_OFS, gt641xx_base_clock / HZ);
 128
 129         cd = &gt641xx_timer0_clockevent;
 130         cd->rating = 200 + gt641xx_base_clock / 10000000;
 131         clockevent_set_clock(cd, gt641xx_base_clock);
 132         cd->max_delta_ns = clockevent_delta2ns(0x7fffffff, cd);
 133         cd->min_delta_ns = clockevent_delta2ns(0x300, cd);
 134         cd->cpumask = cpumask_of(0);
 135
 136         clockevents_register_device(&gt641xx_timer0_clockevent);
 137
 138         return setup_irq(GT641XX_TIMER0_IRQ, &gt641xx_timer0_irqaction);
 139 }
 140 arch_initcall(gt641xx_timer0_clockevent_init);