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  * Handy KS8695 register access functions.
  28  */
  29 #define ks8695_read(a)    *((volatile ulong *) (KS8695_IO_BASE + (a)))
  30 #define ks8695_write(a,v) *((volatile ulong *) (KS8695_IO_BASE + (a))) = (v)
  31
  32 ulong timer_ticks;
  33
  34 int timer_init (void)
  35 {
  36         reset_timer();
  37
  38         return 0;
  39 }
  40
  41 /*
  42  * Initial timer set constants. Nothing complicated, just set for a 1ms
  43  * tick.
  44  */
  45 #define TIMER_INTERVAL  (TICKS_PER_uSEC * mSEC_1)
  46 #define TIMER_COUNT     (TIMER_INTERVAL / 2)
  47 #define TIMER_PULSE     TIMER_COUNT
  48
  49 void reset_timer_masked(void)
  50 {
  51         /* Set the hadware timer for 1ms */
  52         ks8695_write(KS8695_TIMER1, TIMER_COUNT);
  53         ks8695_write(KS8695_TIMER1_PCOUNT, TIMER_PULSE);
  54         ks8695_write(KS8695_TIMER_CTRL, 0x2);
  55         timer_ticks = 0;
  56 }
  57
  58 void reset_timer(void)
  59 {
  60         reset_timer_masked();
  61 }
  62
  63 ulong get_timer_masked(void)
  64 {
  65         /* Check for timer wrap */
  66         if (ks8695_read(KS8695_INT_STATUS) & KS8695_INTMASK_TIMERINT1) {
  67                 /* Clear interrupt condition */
  68                 ks8695_write(KS8695_INT_STATUS, KS8695_INTMASK_TIMERINT1);
  69                 timer_ticks++;
  70         }
  71         return timer_ticks;
  72 }
  73
  74 ulong get_timer(ulong base)
  75 {
  76        return (get_timer_masked() - base);
  77 }
  78
  79 void set_timer(ulong t)
  80 {
  81         timer_ticks = t;
  82 }
  83
  84 void udelay(ulong usec)
  85 {
  86         ulong start = get_timer_masked();
  87         ulong end;
  88
  89         /* Only 1ms resolution :-( */
  90         end = usec / 1000;
  91         while (get_timer(start) < end)
  92                 ;
  93 }
  94
  95 void reset_cpu (ulong ignored)
  96 {
  97         ulong tc;
  98
  99         /* Set timer0 to watchdog, and let it timeout */
 100         tc = ks8695_read(KS8695_TIMER_CTRL) & 0x2;
 101         ks8695_write(KS8695_TIMER_CTRL, tc);
 102         ks8695_write(KS8695_TIMER0, ((10 << 8) | 0xff));
 103         ks8695_write(KS8695_TIMER_CTRL, (tc | 0x1));
 104
 105         /* Should only wait here till watchdog resets */
 106         for (;;)
 107                 ;
 108 }