cpu/arm920t/s3c24x0/interrupts.c

   1 /*
   2  * (C) Copyright 2002
   3  * Sysgo Real-Time Solutions, GmbH <www.elinos.com>
   4  * Marius Groeger <mgroeger@sysgo.de>
   5  *
   6  * (C) Copyright 2002
   7  * Sysgo Real-Time Solutions, GmbH <www.elinos.com>
   8  * Alex Zuepke <azu@sysgo.de>
   9  *
  10  * (C) Copyright 2002
  11  * Gary Jennejohn, DENX Software Engineering, <gj@denx.de>
  12  *
  13  * See file CREDITS for list of people who contributed to this
  14  * project.
  15  *
  16  * This program is free software; you can redistribute it and/or
  17  * modify it under the terms of the GNU General Public License as
  18  * published by the Free Software Foundation; either version 2 of
  19  * the License, or (at your option) any later version.
  20  *
  21  * This program is distributed in the hope that it will be useful,
  22  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  23  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  24  * GNU General Public License for more details.
  25  *
  26  * You should have received a copy of the GNU General Public License
  27  * along with this program; if not, write to the Free Software
  28  * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
  29  * MA 02111-1307 USA
  30  */
  31
  32 #include <common.h>
  33 #if defined(CONFIG_S3C2400) || defined (CONFIG_S3C2410) || defined (CONFIG_TRAB)
  34
  35 #include <arm920t.h>
  36 #if defined(CONFIG_S3C2400)
  37 #include <s3c2400.h>
  38 #elif defined(CONFIG_S3C2410)
  39 #include <s3c2410.h>
  40 #endif
  41
  42 extern void reset_cpu(ulong addr);
  43 int timer_load_val = 0;
  44
  45 /* macro to read the 16 bit timer */
  46 static inline ulong READ_TIMER(void)
  47 {
  48         S3C24X0_TIMERS * const timers = S3C24X0_GetBase_TIMERS();
  49
  50         return (timers->TCNTO4 & 0xffff);
  51 }
  52
  53 static ulong timestamp;
  54 static ulong lastdec;
  55
  56 int interrupt_init (void)
  57 {
  58         S3C24X0_TIMERS * const timers = S3C24X0_GetBase_TIMERS();
  59
  60         /* use PWM Timer 4 because it has no output */
  61         /* prescaler for Timer 4 is 16 */
  62         timers->TCFG0 = 0x0f00;
  63         if (timer_load_val == 0)
  64         {
  65                 /*
  66                  * for 10 ms clock period @ PCLK with 4 bit divider = 1/2
  67                  * (default) and prescaler = 16. Should be 10390
  68                  * @33.25MHz and 15625 @ 50 MHz
  69                  */
  70                 timer_load_val = get_PCLK()/(2 * 16 * 100);
  71         }
  72         /* load value for 10 ms timeout */
  73         lastdec = timers->TCNTB4 = timer_load_val;
  74         /* auto load, manual update of Timer 4 */
  75         timers->TCON = (timers->TCON & ~0x0700000) | 0x600000;
  76         /* auto load, start Timer 4 */
  77         timers->TCON = (timers->TCON & ~0x0700000) | 0x500000;
  78         timestamp = 0;
  79
  80         return (0);
  81 }
  82
  83 /*
  84  * timer without interrupts
  85  */
  86
  87 void reset_timer (void)
  88 {
  89         reset_timer_masked ();
  90 }
  91
  92 ulong get_timer (ulong base)
  93 {
  94         return get_timer_masked () - base;
  95 }
  96
  97 void set_timer (ulong t)
  98 {
  99         timestamp = t;
 100 }
 101
 102 void udelay (unsigned long usec)
 103 {
 104         ulong tmo;
 105         ulong start = get_timer(0);
 106
 107         tmo = usec / 1000;
 108         tmo *= (timer_load_val * 100);
 109         tmo /= 1000;
 110
 111         while ((ulong)(get_timer_masked () - start) < tmo)
 112                 /*NOP*/;
 113 }
 114
 115 void reset_timer_masked (void)
 116 {
 117         /* reset time */
 118         lastdec = READ_TIMER();
 119         timestamp = 0;
 120 }
 121
 122 ulong get_timer_masked (void)
 123 {
 124         ulong now = READ_TIMER();
 125
 126         if (lastdec >= now) {
 127                 /* normal mode */
 128                 timestamp += lastdec - now;
 129         } else {
 130                 /* we have an overflow ... */
 131                 timestamp += lastdec + timer_load_val - now;
 132         }
 133         lastdec = now;
 134
 135         return timestamp;
 136 }
 137
 138 void udelay_masked (unsigned long usec)
 139 {
 140         ulong tmo;
 141
 142         tmo = usec / 1000;
 143         tmo *= (timer_load_val * 100);
 144         tmo /= 1000;
 145
 146         reset_timer_masked ();
 147
 148         while (get_timer_masked () < tmo)
 149                 /*NOP*/;
 150 }
 151
 152 /*
 153  * This function is derived from PowerPC code (read timebase as long long).
 154  * On ARM it just returns the timer value.
 155  */
 156 unsigned long long get_ticks(void)
 157 {
 158         return get_timer(0);
 159 }
 160
 161 /*
 162  * This function is derived from PowerPC code (timebase clock frequency).
 163  * On ARM it returns the number of timer ticks per second.
 164  */
 165 ulong get_tbclk (void)
 166 {
 167         ulong tbclk;
 168
 169 #if defined(CONFIG_SMDK2400) || defined(CONFIG_TRAB)
 170         tbclk = timer_load_val * 100;
 171 #elif defined(CONFIG_SMDK2410) || defined(CONFIG_VCMA9)
 172         tbclk = CFG_HZ;
 173 #else
 174 #       error "tbclk not configured"
 175 #endif
 176
 177         return tbclk;
 178 }
 179
 180 #endif /* defined(CONFIG_S3C2400) || defined (CONFIG_S3C2410) || defined (CONFIG_TRAB) */