cpu/ixp/interrupts.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_USE_IRQ
  36 #include <asm/proc-armv/ptrace.h>
  37
  38 /*
  39  * When interrupts are enabled, use timer 2 for time/delay generation...
  40  */
  41
  42 #define FREQ            66666666
  43 #define CLOCK_TICK_RATE (((FREQ / CFG_HZ & ~IXP425_OST_RELOAD_MASK) + 1) * CFG_HZ)
  44 #define LATCH           ((CLOCK_TICK_RATE + CFG_HZ/2) / CFG_HZ) /* For divider */
  45
  46 struct _irq_handler {
  47         void                *m_data;
  48         void (*m_func)( void *data);
  49 };
  50
  51 static struct _irq_handler IRQ_HANDLER[N_IRQS];
  52
  53 static volatile ulong timestamp;
  54
  55 static void default_isr(void *data)
  56 {
  57         printf("default_isr():  called for IRQ %d, Interrupt Status=%x PR=%x\n",
  58                (int)data, *IXP425_ICIP, *IXP425_ICIH);
  59 }
  60
  61 static int next_irq(void)
  62 {
  63         return (((*IXP425_ICIH & 0x000000fc) >> 2) - 1);
  64 }
  65
  66 static void timer_isr(void *data)
  67 {
  68         unsigned int *pTime = (unsigned int *)data;
  69
  70         (*pTime)++;
  71
  72         /*
  73          * Reset IRQ source
  74          */
  75         *IXP425_OSST = IXP425_OSST_TIMER_2_PEND;
  76 }
  77
  78 ulong get_timer (ulong base)
  79 {
  80         return timestamp - base;
  81 }
  82
  83 void reset_timer (void)
  84 {
  85         timestamp = 0;
  86 }
  87
  88 #endif /* #ifdef CONFIG_USE_IRQ */
  89
  90 #ifdef CONFIG_USE_IRQ
  91 void do_irq (struct pt_regs *pt_regs)
  92 {
  93         int irq = next_irq();
  94
  95         IRQ_HANDLER[irq].m_func(IRQ_HANDLER[irq].m_data);
  96 }
  97 #endif
  98
  99 int interrupt_init (void)
 100 {
 101 #ifdef CONFIG_USE_IRQ
 102         int i;
 103
 104         /* install default interrupt handlers */
 105         for (i = 0; i < N_IRQS; i++) {
 106                 IRQ_HANDLER[i].m_data = (void *)i;
 107                 IRQ_HANDLER[i].m_func = default_isr;
 108         }
 109
 110         /* install interrupt handler for timer */
 111         IRQ_HANDLER[IXP425_TIMER_2_IRQ].m_data = (void *)&timestamp;
 112         IRQ_HANDLER[IXP425_TIMER_2_IRQ].m_func = timer_isr;
 113
 114         /* setup the Timer counter value */
 115         *IXP425_OSRT2 = (LATCH & ~IXP425_OST_RELOAD_MASK) | IXP425_OST_ENABLE;
 116
 117         /* configure interrupts for IRQ mode */
 118         *IXP425_ICLR = 0x00000000;
 119
 120         /* enable timer irq */
 121         *IXP425_ICMR = (1 << IXP425_TIMER_2_IRQ);
 122 #endif
 123
 124         return (0);
 125 }