cpu/bf533/interrupts.c

   1 /*
   2  * U-boot - interrupts.c Interrupt related routines
   3  *
   4  * Copyright (c) 2005 blackfin.uclinux.org
   5  *
   6  * This file is based on interrupts.c
   7  * Copyright 1996 Roman Zippel
   8  * Copyright 1999 D. Jeff Dionne <jeff@uclinux.org>
   9  * Copyright 2000-2001 Lineo, Inc. D. Jefff Dionne <jeff@lineo.ca>
  10  * Copyright 2002 Arcturus Networks Inc. MaTed <mated@sympatico.ca>
  11  * Copyright 2003 Metrowerks/Motorola
  12  * Copyright 2003 Bas Vermeulen <bas@buyways.nl>,
  13  *                      BuyWays B.V. (www.buyways.nl)
  14  *
  15  * (C) Copyright 2000-2004
  16  * Wolfgang Denk, DENX Software Engineering, wd@denx.de.
  17
  18  * See file CREDITS for list of people who contributed to this
  19  * project.
  20  *
  21  * This program is free software; you can redistribute it and/or
  22  * modify it under the terms of the GNU General Public License as
  23  * published by the Free Software Foundation; either version 2 of
  24  * the License, or (at your option) any later version.
  25  *
  26  * This program is distributed in the hope that it will be useful,
  27  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  28  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  29  * GNU General Public License for more details.
  30  *
  31  * You should have received a copy of the GNU General Public License
  32  * along with this program; if not, write to the Free Software
  33  * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
  34  * MA 02111-1307 USA
  35  */
  36
  37 #include <common.h>
  38 #include <asm/machdep.h>
  39 #include <asm/irq.h>
  40 #include <asm/cpu/defBF533.h>
  41 #include "cpu.h"
  42
  43 static ulong timestamp;
  44 static ulong last_time;
  45 static int int_flag;
  46
  47 int irq_flags; /* needed by asm-blackfin/system.h */
  48
  49 /* Functions just to satisfy the linker */
  50
  51 /*
  52  * This function is derived from PowerPC code (read timebase as long long).
  53  * On BF533 it just returns the timer value.
  54  */
  55 unsigned long long get_ticks(void)
  56 {
  57         return get_timer(0);
  58 }
  59
  60 /*
  61  * This function is derived from PowerPC code (timebase clock frequency).
  62  * On BF533 it returns the number of timer ticks per second.
  63  */
  64 ulong get_tbclk (void)
  65 {
  66         ulong tbclk;
  67
  68         tbclk = CFG_HZ;
  69         return tbclk;
  70 }
  71
  72 void enable_interrupts(void)
  73 {
  74         restore_flags(int_flag);
  75 }
  76
  77 int disable_interrupts(void)
  78 {
  79         save_and_cli(int_flag);
  80         return 1;
  81 }
  82
  83 int interrupt_init(void)
  84 {
  85         return (0);
  86 }
  87
  88 void udelay(unsigned long usec)
  89 {
  90         unsigned long delay, start, stop;
  91         unsigned long cclk;
  92         cclk = (CONFIG_CCLK_HZ);
  93
  94         while ( usec > 1 ) {
  95                /*
  96                 * how many clock ticks to delay?
  97                 *  - request(in useconds) * clock_ticks(Hz) / useconds/second
  98                 */
  99                 if (usec < 1000) {
 100                         delay = (usec * (cclk/244)) >> 12 ;
 101                         usec = 0;
 102                 } else {
 103                         delay = (1000 * (cclk/244)) >> 12 ;
 104                         usec -= 1000;
 105                 }
 106
 107                 asm volatile (" %0 = CYCLES;": "=g"(start));
 108                 do {
 109                         asm volatile (" %0 = CYCLES; ": "=g"(stop));
 110                 } while (stop - start < delay);
 111         }
 112
 113         return;
 114 }
 115
 116 void timer_init(void)
 117 {
 118         *pTCNTL = 0x1;
 119         *pTSCALE = 0x0;
 120         *pTCOUNT  = MAX_TIM_LOAD;
 121         *pTPERIOD = MAX_TIM_LOAD;
 122         *pTCNTL = 0x7;
 123         asm("CSYNC;");
 124
 125         timestamp = 0;
 126         last_time = 0;
 127 }
 128
 129 /* Any network command or flash
 130  * command is started get_timer shall
 131  * be called before TCOUNT gets reset,
 132  * to implement the accurate timeouts.
 133  *
 134  * How ever milliconds doesn't return
 135  * the number that has been elapsed from
 136  * the last reset.
 137  *
 138  *  As get_timer is used in the u-boot
 139  *  only for timeouts this should be
 140  *  sufficient
 141  */
 142 ulong get_timer(ulong base)
 143 {
 144         ulong milisec;
 145
 146         /* Number of clocks elapsed */
 147         ulong clocks = (MAX_TIM_LOAD - (*pTCOUNT));
 148
 149         /* Find if the TCOUNT is reset
 150         timestamp gives the number of times
 151         TCOUNT got reset */
 152         if(clocks < last_time)
 153                 timestamp++;
 154         last_time = clocks;
 155
 156         /* Get the number of milliseconds */
 157         milisec = clocks/(CONFIG_CCLK_HZ / 1000);
 158
 159         /* Find the number of millisonds
 160         that got elapsed before this TCOUNT
 161         cycle */
 162         milisec += timestamp * (MAX_TIM_LOAD/(CONFIG_CCLK_HZ / 1000));
 163
 164         return (milisec - base);
 165 }