hw/nios2/cpu_pic.c

   1 /*
   2  * Altera Nios2 CPU PIC
   3  *
   4  * Copyright (c) 2016 Marek Vasut <marek.vasut@gmail.com>
   5  *
   6  * This library is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU Lesser General Public
   8  * License as published by the Free Software Foundation; either
   9  * version 2.1 of the License, or (at your option) any later version.
  10  *
  11  * This library is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14  * Lesser General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU Lesser General Public
  17  * License along with this library; if not, see
  18  * <http://www.gnu.org/licenses/lgpl-2.1.html>
  19  */
  20
  21 #include "qemu/osdep.h"
  22 #include "cpu.h"
  23 #include "hw/irq.h"
  24
  25 #include "qemu/config-file.h"
  26
  27 #include "boot.h"
  28
  29 static void nios2_pic_cpu_handler(void *opaque, int irq, int level)
  30 {
  31     Nios2CPU *cpu = opaque;
  32     CPUNios2State *env = &cpu->env;
  33     CPUState *cs = CPU(cpu);
  34     int type = irq ? CPU_INTERRUPT_NMI : CPU_INTERRUPT_HARD;
  35
  36     if (type == CPU_INTERRUPT_HARD) {
  37         env->irq_pending = level;
  38
  39         if (level && (env->regs[CR_STATUS] & CR_STATUS_PIE)) {
  40             env->irq_pending = 0;
  41             cpu_interrupt(cs, type);
  42         } else if (!level) {
  43             env->irq_pending = 0;
  44             cpu_reset_interrupt(cs, type);
  45         }
  46     } else {
  47         if (level) {
  48             cpu_interrupt(cs, type);
  49         } else {
  50             cpu_reset_interrupt(cs, type);
  51         }
  52     }
  53 }
  54
  55 void nios2_check_interrupts(CPUNios2State *env)
  56 {
  57     if (env->irq_pending) {
  58         env->irq_pending = 0;
  59         cpu_interrupt(env_cpu(env), CPU_INTERRUPT_HARD);
  60     }
  61 }
  62
  63 qemu_irq *nios2_cpu_pic_init(Nios2CPU *cpu)
  64 {
  65     return qemu_allocate_irqs(nios2_pic_cpu_handler, cpu, 2);
  66 }