kernel/arch/score/kernel/time.c

   1 /*
   2  * arch/score/kernel/time.c
   3  *
   4  * Score Processor version.
   5  *
   6  * Copyright (C) 2009 Sunplus Core Technology Co., Ltd.
   7  *  Chen Liqin <liqin.chen@sunplusct.com>
   8  *  Lennox Wu <lennox.wu@sunplusct.com>
   9  *
  10  * This program is free software; you can redistribute it and/or modify
  11  * it under the terms of the GNU General Public License as published by
  12  * the Free Software Foundation; either version 2 of the License, or
  13  * (at your option) any later version.
  14  *
  15  * This program is distributed in the hope that it will be useful,
  16  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  17  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18  * GNU General Public License for more details.
  19  *
  20  * You should have received a copy of the GNU General Public License
  21  * along with this program; if not, see the file COPYING, or write
  22  * to the Free Software Foundation, Inc.,
  23  * 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  24  */
  25
  26 #include <linux/clockchips.h>
  27 #include <linux/interrupt.h>
  28
  29 #include <asm/scoreregs.h>
  30
  31 static irqreturn_t timer_interrupt(int irq, void *dev_id)
  32 {
  33         struct clock_event_device *evdev = dev_id;
  34
  35         /* clear timer interrupt flag */
  36         outl(1, P_TIMER0_CPP_REG);
  37         evdev->event_handler(evdev);
  38
  39         return IRQ_HANDLED;
  40 }
  41
  42 static struct irqaction timer_irq = {
  43         .handler = timer_interrupt,
  44         .flags = IRQF_TIMER,
  45         .name = "timer",
  46 };
  47
  48 static int score_timer_set_next_event(unsigned long delta,
  49                 struct clock_event_device *evdev)
  50 {
  51         outl((TMR_M_PERIODIC | TMR_IE_ENABLE), P_TIMER0_CTRL);
  52         outl(delta, P_TIMER0_PRELOAD);
  53         outl(inl(P_TIMER0_CTRL) | TMR_ENABLE, P_TIMER0_CTRL);
  54
  55         return 0;
  56 }
  57
  58 static int score_timer_set_periodic(struct clock_event_device *evt)
  59 {
  60         outl((TMR_M_PERIODIC | TMR_IE_ENABLE), P_TIMER0_CTRL);
  61         outl(SYSTEM_CLOCK / HZ, P_TIMER0_PRELOAD);
  62         outl(inl(P_TIMER0_CTRL) | TMR_ENABLE, P_TIMER0_CTRL);
  63         return 0;
  64 }
  65
  66 static struct clock_event_device score_clockevent = {
  67         .name                   = "score_clockevent",
  68         .features               = CLOCK_EVT_FEAT_PERIODIC,
  69         .shift                  = 16,
  70         .set_next_event         = score_timer_set_next_event,
  71         .set_state_periodic     = score_timer_set_periodic,
  72 };
  73
  74 void __init time_init(void)
  75 {
  76         timer_irq.dev_id = &score_clockevent;
  77         setup_irq(IRQ_TIMER , &timer_irq);
  78
  79         /* setup COMPARE clockevent */
  80         score_clockevent.mult = div_sc(SYSTEM_CLOCK, NSEC_PER_SEC,
  81                                         score_clockevent.shift);
  82         score_clockevent.max_delta_ns = clockevent_delta2ns((u32)~0,
  83                                         &score_clockevent);
  84         score_clockevent.min_delta_ns = clockevent_delta2ns(50,
  85                                                 &score_clockevent) + 1;
  86         score_clockevent.cpumask = cpumask_of(0);
  87         clockevents_register_device(&score_clockevent);
  88 }