arch/arm/mach-s3c3410/time.c

   1 /*
   2  *  linux/arch/armnommu/mach-s3c3410/time.c
   3  *
   4  *  Copyright (C) SAMSUNG ELECTRONICS
   5  *                      Hyok S. Choi <hyok.choi@samsung.com>
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License as published by
   9  * the Free Software Foundation; either version 2 of the License, or
  10  * (at your option) any later version.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  * GNU General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU General Public License
  18  * along with this program; if not, write to the Free Software
  19  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  20  */
  21 #include <linux/kernel.h>
  22 #include <linux/sched.h>
  23 #include <linux/init.h>
  24 #include <linux/interrupt.h>
  25 #include <asm/system.h>
  26 #include <asm/leds.h>
  27 #include <asm/mach-types.h>
  28
  29 #include <asm/io.h>
  30 #include <asm/irq.h>
  31 #include <asm/hardware.h>
  32 #include <asm/mach/time.h>
  33 #include <asm/arch/time.h>
  34
  35
  36 extern void s3c3410_unmask_irq(unsigned int irq);
  37
  38 unsigned long s3c3410_gettimeoffset (void)
  39 {
  40         return (inw(S3C3410X_TCNT0) / CLOCKS_PER_USEC);
  41 }
  42
  43 static irqreturn_t
  44 s3c3410_timer_interrupt(int irq, void *dev_id)
  45 {
  46     timer_tick();
  47
  48     return IRQ_HANDLED;
  49 }
  50
  51 static struct irqaction s3c3410_timer_irq = {
  52         .name           = "S3C3410 Timer Tick",
  53         .flags          = IRQF_DISABLED | IRQF_TIMER,
  54         .handler        = s3c3410_timer_interrupt
  55 };
  56
  57 /*
  58  * Set up timer interrupt, and return the current time in seconds.
  59  */
  60
  61 void __init  s3c3410_time_init (void)
  62 {
  63         u_int8_t tmod;
  64         u_int16_t period;
  65
  66         /*
  67          * disable and clear timer 0, set to
  68          * internal clock and interval mode
  69          */
  70         tmod = S3C3410X_T16_OMS_INTRV | S3C3410X_T16_CL;
  71         outb(tmod, S3C3410X_TCON0);
  72
  73         /* initialize the timer period and prescaler */
  74         period = (CONFIG_ARM_CLK/S3C3410X_TIMER0_PRESCALER)/HZ;
  75         outw(period, S3C3410X_TDAT0);
  76         outb(S3C3410X_TIMER0_PRESCALER-1, S3C3410X_TPRE0);
  77
  78         /*
  79          * @todo do those really need to be function pointers ?
  80          */
  81         gettimeoffset     = s3c3410_gettimeoffset;
  82         s3c3410_timer_irq.handler = s3c3410_timer_interrupt;
  83
  84         /* set up the interrupt vevtor for timer 0 match */
  85         setup_irq(S3C3410X_INTERRUPT_TMC0, &s3c3410_timer_irq);
  86
  87         /* enable the timer IRQ */
  88         s3c3410_unmask_irq(S3C3410X_INTERRUPT_TMC0);
  89
  90         /* let timer 0 run... */
  91         tmod |= S3C3410X_T16_TEN;
  92         tmod &= ~S3C3410X_T16_CL;
  93         outb(tmod, S3C3410X_TCON0);
  94 }
  95