hw/intc/nios2_iic.c

   1 /*
   2  * QEMU Altera Internal Interrupt Controller.
   3  *
   4  * Copyright (c) 2012 Chris Wulff <crwulff@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 "qemu/module.h"
  23 #include "qapi/error.h"
  24
  25 #include "hw/irq.h"
  26 #include "hw/sysbus.h"
  27 #include "cpu.h"
  28 #include "qom/object.h"
  29
  30 #define TYPE_ALTERA_IIC "altera,iic"
  31 OBJECT_DECLARE_SIMPLE_TYPE(AlteraIIC, ALTERA_IIC)
  32
  33 struct AlteraIIC {
  34     SysBusDevice  parent_obj;
  35     void         *cpu;
  36     qemu_irq      parent_irq;
  37 };
  38
  39 static void update_irq(AlteraIIC *pv)
  40 {
  41     CPUNios2State *env = &((Nios2CPU *)(pv->cpu))->env;
  42
  43     qemu_set_irq(pv->parent_irq,
  44                  env->regs[CR_IPENDING] & env->regs[CR_IENABLE]);
  45 }
  46
  47 static void irq_handler(void *opaque, int irq, int level)
  48 {
  49     AlteraIIC *pv = opaque;
  50     CPUNios2State *env = &((Nios2CPU *)(pv->cpu))->env;
  51
  52     env->regs[CR_IPENDING] &= ~(1 << irq);
  53     env->regs[CR_IPENDING] |= !!level << irq;
  54
  55     update_irq(pv);
  56 }
  57
  58 static void altera_iic_init(Object *obj)
  59 {
  60     AlteraIIC *pv = ALTERA_IIC(obj);
  61
  62     qdev_init_gpio_in(DEVICE(pv), irq_handler, 32);
  63     sysbus_init_irq(SYS_BUS_DEVICE(obj), &pv->parent_irq);
  64 }
  65
  66 static void altera_iic_realize(DeviceState *dev, Error **errp)
  67 {
  68     struct AlteraIIC *pv = ALTERA_IIC(dev);
  69
  70     pv->cpu = object_property_get_link(OBJECT(dev), "cpu", &error_abort);
  71 }
  72
  73 static void altera_iic_class_init(ObjectClass *klass, void *data)
  74 {
  75     DeviceClass *dc = DEVICE_CLASS(klass);
  76
  77     /* Reason: needs to be wired up, e.g. by nios2_10m50_ghrd_init() */
  78     dc->user_creatable = false;
  79     dc->realize = altera_iic_realize;
  80 }
  81
  82 static TypeInfo altera_iic_info = {
  83     .name          = TYPE_ALTERA_IIC,
  84     .parent        = TYPE_SYS_BUS_DEVICE,
  85     .instance_size = sizeof(AlteraIIC),
  86     .instance_init = altera_iic_init,
  87     .class_init    = altera_iic_class_init,
  88 };
  89
  90 static void altera_iic_register(void)
  91 {
  92     type_register_static(&altera_iic_info);
  93 }
  94
  95 type_init(altera_iic_register)