cpu/arm1136/interrupts.c

   1 /*
   2  * (C) Copyright 2004
   3  * Texas Instruments
   4  * Richard Woodruff <r-woodruff2@ti.com>
   5  *
   6  * (C) Copyright 2002
   7  * Sysgo Real-Time Solutions, GmbH <www.elinos.com>
   8  * Marius Groeger <mgroeger@sysgo.de>
   9  * Alex Zuepke <azu@sysgo.de>
  10  *
  11  * (C) Copyright 2002
  12  * Gary Jennejohn, DENX Software Engineering, <gj@denx.de>
  13  *
  14  * See file CREDITS for list of people who contributed to this
  15  * project.
  16  *
  17  * This program is free software; you can redistribute it and/or
  18  * modify it under the terms of the GNU General Public License as
  19  * published by the Free Software Foundation; either version 2 of
  20  * the License, or (at your option) any later version.
  21  *
  22  * This program is distributed in the hope that it will be useful,
  23  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  24  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  25  * GNU General Public License for more details.
  26  *
  27  * You should have received a copy of the GNU General Public License
  28  * along with this program; if not, write to the Free Software
  29  * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
  30  * MA 02111-1307 USA
  31  */
  32
  33 #include <common.h>
  34 #include <asm/arch/bits.h>
  35
  36 #if !defined(CONFIG_INTEGRATOR) && ! defined(CONFIG_ARCH_CINTEGRATOR)
  37 # include <asm/arch/omap2420.h>
  38 #endif
  39
  40 #define TIMER_LOAD_VAL 0
  41
  42 /* macro to read the 32 bit timer */
  43 #define READ_TIMER (*(volatile ulong *)(CFG_TIMERBASE+TCRR))
  44
  45 #if defined(CONFIG_INTEGRATOR) && defined(CONFIG_ARCH_CINTEGRATOR)
  46 /* Use the IntegratorCP function from board/integratorcp.c */
  47 #else
  48
  49 static ulong timestamp;
  50 static ulong lastinc;
  51
  52 /* nothing really to do with interrupts, just starts up a counter. */
  53 int interrupt_init (void)
  54 {
  55         int32_t val;
  56
  57         /* Start the counter ticking up */
  58         *((int32_t *) (CFG_TIMERBASE + TLDR)) = TIMER_LOAD_VAL; /* reload value on overflow*/
  59         val = (CFG_PVT << 2) | BIT5 | BIT1 | BIT0;              /* mask to enable timer*/
  60         *((int32_t *) (CFG_TIMERBASE + TCLR)) = val;    /* start timer */
  61
  62         reset_timer_masked(); /* init the timestamp and lastinc value */
  63
  64         return(0);
  65 }
  66 /*
  67  * timer without interrupts
  68  */
  69 void reset_timer (void)
  70 {
  71         reset_timer_masked ();
  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         timestamp = t;
  82 }
  83
  84 /* delay x useconds AND perserve advance timstamp value */
  85 void udelay (unsigned long usec)
  86 {
  87         ulong tmo, tmp;
  88
  89         if (usec >= 1000) {                     /* if "big" number, spread normalization to seconds */
  90                 tmo = usec / 1000;              /* start to normalize for usec to ticks per sec */
  91                 tmo *= CFG_HZ;                  /* find number of "ticks" to wait to achieve target */
  92                 tmo /= 1000;                    /* finish normalize. */
  93         } else {                                        /* else small number, don't kill it prior to HZ multiply */
  94                 tmo = usec * CFG_HZ;
  95                 tmo /= (1000*1000);
  96         }
  97
  98         tmp = get_timer (0);            /* get current timestamp */
  99         if ( (tmo + tmp + 1) < tmp )/* if setting this forward will roll time stamp */
 100                 reset_timer_masked ();  /* reset "advancing" timestamp to 0, set lastinc value */
 101         else
 102                 tmo     += tmp;                         /* else, set advancing stamp wake up time */
 103         while (get_timer_masked () < tmo)/* loop till event */
 104                 /*NOP*/;
 105 }
 106
 107 void reset_timer_masked (void)
 108 {
 109         /* reset time */
 110         lastinc = READ_TIMER;           /* capture current incrementer value time */
 111         timestamp = 0;                          /* start "advancing" time stamp from 0 */
 112 }
 113
 114 ulong get_timer_masked (void)
 115 {
 116         ulong now = READ_TIMER;         /* current tick value */
 117
 118         if (now >= lastinc)                     /* normal mode (non roll) */
 119                 timestamp += (now - lastinc); /* move stamp fordward with absoulte diff ticks */
 120         else                                            /* we have rollover of incrementer */
 121                 timestamp += (0xFFFFFFFF - lastinc) + now;
 122         lastinc = now;
 123         return timestamp;
 124 }
 125
 126 /* waits specified delay value and resets timestamp */
 127 void udelay_masked (unsigned long usec)
 128 {
 129         ulong tmo;
 130         ulong endtime;
 131         signed long diff;
 132
 133         if (usec >= 1000) {                     /* if "big" number, spread normalization to seconds */
 134                 tmo = usec / 1000;              /* start to normalize for usec to ticks per sec */
 135                 tmo *= CFG_HZ;                  /* find number of "ticks" to wait to achieve target */
 136                 tmo /= 1000;                    /* finish normalize. */
 137         } else {                                        /* else small number, don't kill it prior to HZ multiply */
 138                 tmo = usec * CFG_HZ;
 139                 tmo /= (1000*1000);
 140         }
 141         endtime = get_timer_masked () + tmo;
 142
 143         do {
 144                 ulong now = get_timer_masked ();
 145                 diff = endtime - now;
 146         } while (diff >= 0);
 147 }
 148
 149 /*
 150  * This function is derived from PowerPC code (read timebase as long long).
 151  * On ARM it just returns the timer value.
 152  */
 153 unsigned long long get_ticks(void)
 154 {
 155         return get_timer(0);
 156 }
 157 /*
 158  * This function is derived from PowerPC code (timebase clock frequency).
 159  * On ARM it returns the number of timer ticks per second.
 160  */
 161 ulong get_tbclk (void)
 162 {
 163         ulong tbclk;
 164         tbclk = CFG_HZ;
 165         return tbclk;
 166 }
 167 #endif /* !Integrator/CP */