cpu/lh7a40x/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 #include <arm920t.h>
  34 #include <lh7a40x.h>
  35
  36 static ulong timer_load_val = 0;
  37
  38 /* macro to read the 16 bit timer */
  39 static inline ulong READ_TIMER(void)
  40 {
  41         lh7a40x_timers_t* timers = LH7A40X_TIMERS_PTR;
  42         lh7a40x_timer_t* timer = &timers->timer1;
  43
  44         return (timer->value & 0x0000ffff);
  45 }
  46
  47 static ulong timestamp;
  48 static ulong lastdec;
  49
  50 int interrupt_init (void)
  51 {
  52         lh7a40x_timers_t* timers = LH7A40X_TIMERS_PTR;
  53         lh7a40x_timer_t* timer = &timers->timer1;
  54
  55         /* a periodic timer using the 508kHz source */
  56         timer->control = (TIMER_PER | TIMER_CLK508K);
  57
  58         if (timer_load_val == 0) {
  59                 /*
  60                  * 10ms period with 508.469kHz clock = 5084
  61                  */
  62                 timer_load_val = CONFIG_SYS_HZ/100;
  63         }
  64
  65         /* load value for 10 ms timeout */
  66         lastdec = timer->load = timer_load_val;
  67
  68         /* auto load, start timer */
  69         timer->control = timer->control | TIMER_EN;
  70         timestamp = 0;
  71
  72         return (0);
  73 }
  74
  75 /*
  76  * timer without interrupts
  77  */
  78
  79 void reset_timer (void)
  80 {
  81         reset_timer_masked ();
  82 }
  83
  84 ulong get_timer (ulong base)
  85 {
  86         return (get_timer_masked() - base);
  87 }
  88
  89 void set_timer (ulong t)
  90 {
  91         timestamp = t;
  92 }
  93
  94 void udelay (unsigned long usec)
  95 {
  96         ulong tmo,tmp;
  97
  98         /* normalize */
  99         if (usec >= 1000) {
 100                 tmo = usec / 1000;
 101                 tmo *= CONFIG_SYS_HZ;
 102                 tmo /= 1000;
 103         }
 104         else {
 105                 if (usec > 1) {
 106                         tmo = usec * CONFIG_SYS_HZ;
 107                         tmo /= (1000*1000);
 108                 }
 109                 else
 110                         tmo = 1;
 111         }
 112
 113         /* check for rollover during this delay */
 114         tmp = get_timer (0);
 115         if ((tmp + tmo) < tmp )
 116                 reset_timer_masked();  /* timer would roll over */
 117         else
 118                 tmo += tmp;
 119
 120         while (get_timer_masked () < tmo);
 121 }
 122
 123 void reset_timer_masked (void)
 124 {
 125         /* reset time */
 126         lastdec = READ_TIMER();
 127         timestamp = 0;
 128 }
 129
 130 ulong get_timer_masked (void)
 131 {
 132         ulong now = READ_TIMER();
 133
 134         if (lastdec >= now) {
 135                 /* normal mode */
 136                 timestamp += (lastdec - now);
 137         } else {
 138                 /* we have an overflow ... */
 139                 timestamp += ((lastdec + timer_load_val) - now);
 140         }
 141         lastdec = now;
 142
 143         return timestamp;
 144 }
 145
 146 void udelay_masked (unsigned long usec)
 147 {
 148         ulong tmo;
 149         ulong endtime;
 150         signed long diff;
 151
 152         /* normalize */
 153         if (usec >= 1000) {
 154                 tmo = usec / 1000;
 155                 tmo *= CONFIG_SYS_HZ;
 156                 tmo /= 1000;
 157         } else {
 158                 if (usec > 1) {
 159                         tmo = usec * CONFIG_SYS_HZ;
 160                         tmo /= (1000*1000);
 161                 } else {
 162                         tmo = 1;
 163                 }
 164         }
 165
 166         endtime = get_timer_masked () + tmo;
 167
 168         do {
 169                 ulong now = get_timer_masked ();
 170                 diff = endtime - now;
 171         } while (diff >= 0);
 172 }
 173
 174 /*
 175  * This function is derived from PowerPC code (read timebase as long long).
 176  * On ARM it just returns the timer value.
 177  */
 178 unsigned long long get_ticks(void)
 179 {
 180         return get_timer(0);
 181 }
 182
 183 /*
 184  * This function is derived from PowerPC code (timebase clock frequency).
 185  * On ARM it returns the number of timer ticks per second.
 186  */
 187 ulong get_tbclk (void)
 188 {
 189         ulong tbclk;
 190
 191         tbclk = timer_load_val * 100;
 192
 193         return tbclk;
 194 }