arch/arm/cpu/arm920t/ks8695/timer.c

   1 /*
   2  * (C) Copyright 2004-2005, Greg Ungerer <greg.ungerer@opengear.com>
   3  *
   4  * See file CREDITS for list of people who contributed to this
   5  * project.
   6  *
   7  * This program is free software; you can redistribute it and/or
   8  * modify it under the terms of the GNU General Public License as
   9  * published by the Free Software Foundation; either version 2 of
  10  * the License, or (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,
  20  * MA 02111-1307 USA
  21  */
  22
  23 #include <common.h>
  24 #include <asm/arch/platform.h>
  25
  26 /*
  27  * Initial timer set constants. Nothing complicated, just set for a 1ms
  28  * tick.
  29  */
  30 #define TIMER_INTERVAL  (TICKS_PER_uSEC * mSEC_1)
  31 #define TIMER_COUNT     (TIMER_INTERVAL / 2)
  32 #define TIMER_PULSE     TIMER_COUNT
  33
  34 /*
  35  * Handy KS8695 register access functions.
  36  */
  37 #define ks8695_read(a)    *((volatile ulong *) (KS8695_IO_BASE + (a)))
  38 #define ks8695_write(a,v) *((volatile ulong *) (KS8695_IO_BASE + (a))) = (v)
  39
  40 ulong timer_ticks;
  41
  42 int timer_init (void)
  43 {
  44         /* Set the hadware timer for 1ms */
  45         ks8695_write(KS8695_TIMER1, TIMER_COUNT);
  46         ks8695_write(KS8695_TIMER1_PCOUNT, TIMER_PULSE);
  47         ks8695_write(KS8695_TIMER_CTRL, 0x2);
  48         timer_ticks = 0;
  49
  50         return 0;
  51 }
  52
  53 ulong get_timer_masked(void)
  54 {
  55         /* Check for timer wrap */
  56         if (ks8695_read(KS8695_INT_STATUS) & KS8695_INTMASK_TIMERINT1) {
  57                 /* Clear interrupt condition */
  58                 ks8695_write(KS8695_INT_STATUS, KS8695_INTMASK_TIMERINT1);
  59                 timer_ticks++;
  60         }
  61         return timer_ticks;
  62 }
  63
  64 ulong get_timer(ulong base)
  65 {
  66        return (get_timer_masked() - base);
  67 }
  68
  69 void __udelay(ulong usec)
  70 {
  71         ulong start = get_timer_masked();
  72         ulong end;
  73
  74         /* Only 1ms resolution :-( */
  75         end = usec / 1000;
  76         while (get_timer(start) < end)
  77                 ;
  78 }
  79
  80 void reset_cpu (ulong ignored)
  81 {
  82         ulong tc;
  83
  84         /* Set timer0 to watchdog, and let it timeout */
  85         tc = ks8695_read(KS8695_TIMER_CTRL) & 0x2;
  86         ks8695_write(KS8695_TIMER_CTRL, tc);
  87         ks8695_write(KS8695_TIMER0, ((10 << 8) | 0xff));
  88         ks8695_write(KS8695_TIMER_CTRL, (tc | 0x1));
  89
  90         /* Should only wait here till watchdog resets */
  91         for (;;)
  92                 ;
  93 }