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