cpu/arm946es/interrupts.c

   1 /*
   2  * (C) Copyright 2003
   3  * Texas Instruments <www.ti.com>
   4  *
   5  * (C) Copyright 2002
   6  * Sysgo Real-Time Solutions, GmbH <www.elinos.com>
   7  * Marius Groeger <mgroeger@sysgo.de>
   8  *
   9  * (C) Copyright 2002
  10  * Sysgo Real-Time Solutions, GmbH <www.elinos.com>
  11  * Alex Zuepke <azu@sysgo.de>
  12  *
  13  * (C) Copyright 2002-2004
  14  * Gary Jennejohn, DENX Software Engineering, <garyj@denx.de>
  15  *
  16  * (C) Copyright 2004
  17  * Philippe Robin, ARM Ltd. <philippe.robin@arm.com>
  18  *
  19  * See file CREDITS for list of people who contributed to this
  20  * project.
  21  *
  22  * This program is free software; you can redistribute it and/or
  23  * modify it under the terms of the GNU General Public License as
  24  * published by the Free Software Foundation; either version 2 of
  25  * the License, or (at your option) any later version.
  26  *
  27  * This program is distributed in the hope that it will be useful,
  28  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  29  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  30  * GNU General Public License for more details.
  31  *
  32  * You should have received a copy of the GNU General Public License
  33  * along with this program; if not, write to the Free Software
  34  * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
  35  * MA 02111-1307 USA
  36  */
  37
  38 #include <common.h>
  39 #include <arm946es.h>
  40
  41 #define TIMER_LOAD_VAL 0xffffffff
  42 extern void reset_cpu(ulong addr);
  43
  44 #ifdef CONFIG_INTEGRATOR
  45         /* Timer functionality supplied by Integrator board (AP or CP) */
  46 #else
  47
  48 static ulong timestamp;
  49 static ulong lastdec;
  50
  51 /* nothing really to do with interrupts, just starts up a counter. */
  52 int interrupt_init (void)
  53 {
  54         /* init the timestamp and lastdec value */
  55         reset_timer_masked();
  56
  57         return (0);
  58 }
  59
  60 /*
  61  * timer without interrupts
  62  */
  63
  64 void reset_timer (void)
  65 {
  66         reset_timer_masked ();
  67 }
  68
  69 ulong get_timer (ulong base)
  70 {
  71         return get_timer_masked () - base;
  72 }
  73
  74 void set_timer (ulong t)
  75 {
  76         timestamp = t;
  77 }
  78
  79 /* delay x useconds AND perserve advance timstamp value */
  80 void udelay(unsigned long usec)
  81 {
  82         udelay_masked(usec);
  83 }
  84
  85 void reset_timer_masked (void)
  86 {
  87         /* reset time */
  88         lastdec = READ_TIMER;  /* capure current decrementer value time */
  89         timestamp = 0;         /* start "advancing" time stamp from 0 */
  90 }
  91
  92 ulong get_timer_raw (void)
  93 {
  94         ulong now = READ_TIMER;         /* current tick value */
  95
  96         if (lastdec >= now) {           /* normal mode (non roll) */
  97                 /* normal mode */
  98                 timestamp += lastdec - now; /* move stamp fordward with absoulte diff ticks */
  99         } else {                        /* we have overflow of the count down timer */
 100                 /* nts = ts + ld + (TLV - now)
 101                  * ts=old stamp, ld=time that passed before passing through -1
 102                  * (TLV-now) amount of time after passing though -1
 103                  * nts = new "advancing time stamp"...it could also roll and cause problems.
 104                  */
 105                 timestamp += lastdec + TIMER_LOAD_VAL - now;
 106         }
 107         lastdec = now;
 108
 109         return timestamp;
 110 }
 111
 112 ulong get_timer_masked (void)
 113 {
 114         return get_timer_raw() / TIMER_LOAD_VAL;
 115 }
 116
 117 /* waits specified delay value and resets timestamp */
 118 void udelay_masked (unsigned long usec)
 119 {
 120         ulong tmo;
 121
 122         if(usec >= 1000){               /* if "big" number, spread normalization to seconds */
 123                 tmo = usec / 1000;      /* start to normalize for usec to ticks per sec */
 124                 tmo *= CONFIG_SYS_HZ_CLOCK;    /* find number of "ticks" to wait to achieve target */
 125                 tmo /= 1000;            /* finish normalize. */
 126         }else{                          /* else small number, don't kill it prior to HZ multiply */
 127                 tmo = usec * CONFIG_SYS_HZ_CLOCK;
 128                 tmo /= (1000*1000);
 129         }
 130
 131         reset_timer_masked ();  /* set "advancing" timestamp to 0, set lastdec vaule */
 132
 133         while (get_timer_raw () < tmo) /* wait for time stamp to overtake tick number.*/
 134                 /*NOP*/;
 135 }
 136
 137 /*
 138  * This function is derived from PowerPC code (read timebase as long long).
 139  * On ARM it just returns the timer value.
 140  */
 141 unsigned long long get_ticks(void)
 142 {
 143         return get_timer(0);
 144 }
 145
 146 /*
 147  * This function is derived from PowerPC code (timebase clock frequency).
 148  * On ARM it returns the number of timer ticks per second.
 149  */
 150 ulong get_tbclk (void)
 151 {
 152         ulong tbclk;
 153
 154         tbclk = CONFIG_SYS_HZ;
 155         return tbclk;
 156 }
 157
 158 #endif /* CONFIG_INTEGRATOR */