arch/mips/kernel/cevt-gt641xx.c

   1 /*
   2  *  GT641xx clockevent routines.
   3  *
   4  *  Copyright (C) 2007  Yoichi Yuasa <yoichi_yuasa@tripeaks.co.jp>
   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 #include <irq.h>
  29
  30 static DEFINE_SPINLOCK(gt641xx_timer_lock);
  31 static unsigned int gt641xx_base_clock;
  32
  33 void gt641xx_set_base_clock(unsigned int clock)
  34 {
  35         gt641xx_base_clock = clock;
  36 }
  37
  38 int gt641xx_timer0_state(void)
  39 {
  40         if (GT_READ(GT_TC0_OFS))
  41                 return 0;
  42
  43         GT_WRITE(GT_TC0_OFS, gt641xx_base_clock / HZ);
  44         GT_WRITE(GT_TC_CONTROL_OFS, GT_TC_CONTROL_ENTC0_MSK);
  45
  46         return 1;
  47 }
  48
  49 static int gt641xx_timer0_set_next_event(unsigned long delta,
  50                                          struct clock_event_device *evt)
  51 {
  52         u32 ctrl;
  53
  54         spin_lock(&gt641xx_timer_lock);
  55
  56         ctrl = GT_READ(GT_TC_CONTROL_OFS);
  57         ctrl &= ~(GT_TC_CONTROL_ENTC0_MSK | GT_TC_CONTROL_SELTC0_MSK);
  58         ctrl |= GT_TC_CONTROL_ENTC0_MSK;
  59
  60         GT_WRITE(GT_TC0_OFS, delta);
  61         GT_WRITE(GT_TC_CONTROL_OFS, ctrl);
  62
  63         spin_unlock(&gt641xx_timer_lock);
  64
  65         return 0;
  66 }
  67
  68 static void gt641xx_timer0_set_mode(enum clock_event_mode mode,
  69                                     struct clock_event_device *evt)
  70 {
  71         u32 ctrl;
  72
  73         spin_lock(&gt641xx_timer_lock);
  74
  75         ctrl = GT_READ(GT_TC_CONTROL_OFS);
  76         ctrl &= ~(GT_TC_CONTROL_ENTC0_MSK | GT_TC_CONTROL_SELTC0_MSK);
  77
  78         switch (mode) {
  79         case CLOCK_EVT_MODE_PERIODIC:
  80                 ctrl |= GT_TC_CONTROL_ENTC0_MSK | GT_TC_CONTROL_SELTC0_MSK;
  81                 break;
  82         case CLOCK_EVT_MODE_ONESHOT:
  83                 ctrl |= GT_TC_CONTROL_ENTC0_MSK;
  84                 break;
  85         default:
  86                 break;
  87         }
  88
  89         GT_WRITE(GT_TC_CONTROL_OFS, ctrl);
  90
  91         spin_unlock(&gt641xx_timer_lock);
  92 }
  93
  94 static void gt641xx_timer0_event_handler(struct clock_event_device *dev)
  95 {
  96 }
  97
  98 static struct clock_event_device gt641xx_timer0_clockevent = {
  99         .name           = "gt641xx-timer0",
 100         .features       = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT,
 101         .cpumask        = CPU_MASK_CPU0,
 102         .irq            = GT641XX_TIMER0_IRQ,
 103         .set_next_event = gt641xx_timer0_set_next_event,
 104         .set_mode       = gt641xx_timer0_set_mode,
 105         .event_handler  = gt641xx_timer0_event_handler,
 106 };
 107
 108 static irqreturn_t gt641xx_timer0_interrupt(int irq, void *dev_id)
 109 {
 110         struct clock_event_device *cd = &gt641xx_timer0_clockevent;
 111
 112         cd->event_handler(cd);
 113
 114         return IRQ_HANDLED;
 115 }
 116
 117 static struct irqaction gt641xx_timer0_irqaction = {
 118         .handler        = gt641xx_timer0_interrupt,
 119         .flags          = IRQF_DISABLED | IRQF_PERCPU,
 120         .name           = "gt641xx_timer0",
 121 };
 122
 123 static int __init gt641xx_timer0_clockevent_init(void)
 124 {
 125         struct clock_event_device *cd;
 126
 127         if (!gt641xx_base_clock)
 128                 return 0;
 129
 130         GT_WRITE(GT_TC0_OFS, gt641xx_base_clock / HZ);
 131
 132         cd = &gt641xx_timer0_clockevent;
 133         cd->rating = 200 + gt641xx_base_clock / 10000000;
 134         clockevent_set_clock(cd, gt641xx_base_clock);
 135         cd->max_delta_ns = clockevent_delta2ns(0x7fffffff, cd);
 136         cd->min_delta_ns = clockevent_delta2ns(0x300, cd);
 137
 138         clockevents_register_device(&gt641xx_timer0_clockevent);
 139
 140         return setup_irq(GT641XX_TIMER0_IRQ, &gt641xx_timer0_irqaction);
 141 }
 142 arch_initcall(gt641xx_timer0_clockevent_init);