arch/arm/cpu/ixp/timer.c

   1 /*
   2  * (C) Copyright 2006
   3  * Stefan Roese, DENX Software Engineering, sr@denx.de.
   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  * 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 <asm/arch/ixp425.h>
  34
  35 #ifdef CONFIG_TIMER_IRQ
  36
  37 #define FREQ            66666666
  38 #define CLOCK_TICK_RATE (((FREQ / CONFIG_SYS_HZ & ~IXP425_OST_RELOAD_MASK) + 1) * CONFIG_SYS_HZ)
  39 #define LATCH           ((CLOCK_TICK_RATE + CONFIG_SYS_HZ/2) / CONFIG_SYS_HZ)   /* For divider */
  40
  41 /*
  42  * When interrupts are enabled, use timer 2 for time/delay generation...
  43  */
  44
  45 static volatile ulong timestamp;
  46
  47 static void timer_isr(void *data)
  48 {
  49         unsigned int *pTime = (unsigned int *)data;
  50
  51         (*pTime)++;
  52
  53         /*
  54          * Reset IRQ source
  55          */
  56         *IXP425_OSST = IXP425_OSST_TIMER_2_PEND;
  57 }
  58
  59 ulong get_timer (ulong base)
  60 {
  61         return timestamp - base;
  62 }
  63
  64 void reset_timer (void)
  65 {
  66         timestamp = 0;
  67 }
  68
  69 int timer_init (void)
  70 {
  71         /* install interrupt handler for timer */
  72         irq_install_handler(IXP425_TIMER_2_IRQ, timer_isr, (void *)&timestamp);
  73
  74         /* setup the Timer counter value */
  75         *IXP425_OSRT2 = (LATCH & ~IXP425_OST_RELOAD_MASK) | IXP425_OST_ENABLE;
  76
  77         /* enable timer irq */
  78         *IXP425_ICMR = (1 << IXP425_TIMER_2_IRQ);
  79
  80         return 0;
  81 }
  82 #else
  83 ulong get_timer (ulong base)
  84 {
  85        return get_timer_masked () - base;
  86 }
  87
  88 void ixp425_udelay(unsigned long usec)
  89 {
  90         /*
  91          * This function has a max usec, but since it is called from udelay
  92          * we should not have to worry... be happy
  93          */
  94         unsigned long usecs = CONFIG_SYS_HZ/1000000L & ~IXP425_OST_RELOAD_MASK;
  95
  96         *IXP425_OSST = IXP425_OSST_TIMER_1_PEND;
  97         usecs |= IXP425_OST_ONE_SHOT | IXP425_OST_ENABLE;
  98         *IXP425_OSRT1 = usecs;
  99         while (!(*IXP425_OSST & IXP425_OSST_TIMER_1_PEND));
 100 }
 101
 102 void __udelay (unsigned long usec)
 103 {
 104         while (usec--) ixp425_udelay(1);
 105 }
 106
 107 static ulong reload_constant = 0xfffffff0;
 108
 109 void reset_timer_masked (void)
 110 {
 111         ulong reload = reload_constant | IXP425_OST_ONE_SHOT | IXP425_OST_ENABLE;
 112
 113         *IXP425_OSST = IXP425_OSST_TIMER_1_PEND;
 114         *IXP425_OSRT1 = reload;
 115 }
 116
 117 ulong get_timer_masked (void)
 118 {
 119         /*
 120          * Note that it is possible for this to wrap!
 121          * In this case we return max.
 122          */
 123         ulong current = *IXP425_OST1;
 124         if (*IXP425_OSST & IXP425_OSST_TIMER_1_PEND)
 125         {
 126                 return reload_constant;
 127         }
 128         return (reload_constant - current);
 129 }
 130
 131 int timer_init(void)
 132 {
 133         return 0;
 134 }
 135 #endif