hw/intc/i8259.c - qemu - Git at Google

 /*
  * QEMU 8259 interrupt controller emulation
  *
  * Copyright (c) 2003-2004 Fabrice Bellard
  *
  * Permission is hereby granted, free of charge, to any person obtaining a copy
  * of this software and associated documentation files (the "Software"), to deal
  * in the Software without restriction, including without limitation the rights
  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  * copies of the Software, and to permit persons to whom the Software is
  * furnished to do so, subject to the following conditions:
  *
  * The above copyright notice and this permission notice shall be included in
  * all copies or substantial portions of the Software.
  *
  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  * THE SOFTWARE.
  */

 #include "qemu/osdep.h"
 #include "hw/intc/i8259.h"
 #include "hw/irq.h"
 #include "hw/isa/isa.h"
 #include "qemu/timer.h"
 #include "qemu/log.h"
 #include "hw/isa/i8259_internal.h"
 #include "trace.h"
 #include "qom/object.h"

 /* debug PIC */
 //#define DEBUG_PIC

 //#define DEBUG_IRQ_LATENCY

 #define TYPE_I8259 "isa-i8259"
 typedef struct PICClass PICClass;
 DECLARE_CLASS_CHECKERS(PICClass, PIC,
                        TYPE_I8259)

 /**
  * PICClass:
  * @parent_realize: The parent's realizefn.
  */
 struct PICClass {
     PICCommonClass parent_class;

     DeviceRealize parent_realize;
 };

 #ifdef DEBUG_IRQ_LATENCY
 static int64_t irq_time[16];
 #endif
 PICCommonState *isa_pic;
 static PICCommonState *slave_pic;

 /* return the highest priority found in mask (highest = smallest
    number). Return 8 if no irq */
 static int get_priority(PICCommonState *s, int mask)
 {
     int priority;

     if (mask == 0) {
         return 8;
     }
     priority = 0;
     while ((mask & (1 << ((priority + s->priority_add) & 7))) == 0) {
         priority++;
     }
     return priority;
 }

 /* return the pic wanted interrupt. return -1 if none */
 static int pic_get_irq(PICCommonState *s)
 {
     int mask, cur_priority, priority;

     mask = s->irr & ~s->imr;
     priority = get_priority(s, mask);
     if (priority == 8) {
         return -1;
     }
     /* compute current priority. If special fully nested mode on the
        master, the IRQ coming from the slave is not taken into account
        for the priority computation. */
     mask = s->isr;
     if (s->special_mask) {
         mask &= ~s->imr;
     }
     if (s->special_fully_nested_mode && s->master) {
         mask &= ~(1 << 2);
     }
     cur_priority = get_priority(s, mask);
     if (priority < cur_priority) {
         /* higher priority found: an irq should be generated */
         return (priority + s->priority_add) & 7;
     } else {
         return -1;
     }
 }

 /* Update INT output. Must be called every time the output may have changed. */
 static void pic_update_irq(PICCommonState *s)
 {
     int irq;

     irq = pic_get_irq(s);
     if (irq >= 0) {
         trace_pic_update_irq(s->master, s->imr, s->irr, s->priority_add);
         qemu_irq_raise(s->int_out[0]);
     } else {
         qemu_irq_lower(s->int_out[0]);
     }
 }

 /* set irq level. If an edge is detected, then the IRR is set to 1 */
 static void pic_set_irq(void *opaque, int irq, int level)
 {
     PICCommonState *s = opaque;
     int mask = 1 << irq;
     int irq_index = s->master ? irq : irq + 8;

     trace_pic_set_irq(s->master, irq, level);
     pic_stat_update_irq(irq_index, level);

 #ifdef DEBUG_IRQ_LATENCY
     if (level) {
         irq_time[irq_index] = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL);
     }
 #endif

     if (s->ltim || (s->elcr & mask)) {
         /* level triggered */
         if (level) {
             s->irr |= mask;
             s->last_irr |= mask;
         } else {
             s->irr &= ~mask;
             s->last_irr &= ~mask;
         }
     } else {
         /* edge triggered */
         if (level) {
             if ((s->last_irr & mask) == 0) {
                 s->irr |= mask;
             }
             s->last_irr |= mask;
         } else {
             s->last_irr &= ~mask;
         }
     }
     pic_update_irq(s);
 }

 /* acknowledge interrupt 'irq' */
 static void pic_intack(PICCommonState *s, int irq)
 {
     if (s->auto_eoi) {
         if (s->rotate_on_auto_eoi) {
             s->priority_add = (irq + 1) & 7;
         }
     } else {
         s->isr |= (1 << irq);
     }
     /* We don't clear a level sensitive interrupt here */
     if (!s->ltim && !(s->elcr & (1 << irq))) {
         s->irr &= ~(1 << irq);
     }
     pic_update_irq(s);
 }

 int pic_read_irq(PICCommonState *s)
 {
     int irq, intno;

     irq = pic_get_irq(s);
     if (irq >= 0) {
         int irq2;

         if (irq == 2) {
             irq2 = pic_get_irq(slave_pic);
             if (irq2 >= 0) {
                 pic_intack(slave_pic, irq2);
             } else {
                 /* spurious IRQ on slave controller */
                 irq2 = 7;
             }
             intno = slave_pic->irq_base + irq2;
             pic_intack(s, irq);
             irq = irq2 + 8;
         } else {
             intno = s->irq_base + irq;
             pic_intack(s, irq);
         }
     } else {
         /* spurious IRQ on host controller */
         irq = 7;
         intno = s->irq_base + irq;
     }

 #ifdef DEBUG_IRQ_LATENCY
     printf("IRQ%d latency=%0.3fus\n",
            irq,
            (double)(qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL) -
                     irq_time[irq]) * 1000000.0 / NANOSECONDS_PER_SECOND);
 #endif

     trace_pic_interrupt(irq, intno);
     return intno;
 }

 static void pic_init_reset(PICCommonState *s)
 {
     pic_reset_common(s);
     pic_update_irq(s);
 }

 static void pic_reset(DeviceState *dev)
 {
     PICCommonState *s = PIC_COMMON(dev);

     s->elcr = 0;
     s->ltim = 0;
     pic_init_reset(s);
 }

 static void pic_ioport_write(void *opaque, hwaddr addr64,
                              uint64_t val64, unsigned size)
 {
     PICCommonState *s = opaque;
     uint32_t addr = addr64;
     uint32_t val = val64;
     int priority, cmd, irq;

     trace_pic_ioport_write(s->master, addr, val);

     if (addr == 0) {
         if (val & 0x10) {
             pic_init_reset(s);
             s->init_state = 1;
             s->init4 = val & 1;
             s->single_mode = val & 2;
             s->ltim = val & 8;
         } else if (val & 0x08) {
             if (val & 0x04) {
                 s->poll = 1;
             }
             if (val & 0x02) {
                 s->read_reg_select = val & 1;
             }
             if (val & 0x40) {
                 s->special_mask = (val >> 5) & 1;
             }
         } else {
             cmd = val >> 5;
             switch (cmd) {
             case 0:
             case 4:
                 s->rotate_on_auto_eoi = cmd >> 2;
                 break;
             case 1: /* end of interrupt */
             case 5:
                 priority = get_priority(s, s->isr);
                 if (priority != 8) {
                     irq = (priority + s->priority_add) & 7;
                     s->isr &= ~(1 << irq);
                     if (cmd == 5) {
                         s->priority_add = (irq + 1) & 7;
                     }
                     pic_update_irq(s);
                 }
                 break;
             case 3:
                 irq = val & 7;
                 s->isr &= ~(1 << irq);
                 pic_update_irq(s);
                 break;
             case 6:
                 s->priority_add = (val + 1) & 7;
                 pic_update_irq(s);
                 break;
             case 7:
                 irq = val & 7;
                 s->isr &= ~(1 << irq);
                 s->priority_add = (irq + 1) & 7;
                 pic_update_irq(s);
                 break;
             default:
                 /* no operation */
                 break;
             }
         }
     } else {
         switch (s->init_state) {
         case 0:
             /* normal mode */
             s->imr = val;
             pic_update_irq(s);
             break;
         case 1:
             s->irq_base = val & 0xf8;
             s->init_state = s->single_mode ? (s->init4 ? 3 : 0) : 2;
             break;
         case 2:
             if (s->init4) {
                 s->init_state = 3;
             } else {
                 s->init_state = 0;
             }
             break;
         case 3:
             s->special_fully_nested_mode = (val >> 4) & 1;
             s->auto_eoi = (val >> 1) & 1;
             s->init_state = 0;
             break;
         }
     }
 }

 static uint64_t pic_ioport_read(void *opaque, hwaddr addr,
                                 unsigned size)
 {
     PICCommonState *s = opaque;
     int ret;

     if (s->poll) {
         ret = pic_get_irq(s);
         if (ret >= 0) {
             pic_intack(s, ret);
             ret |= 0x80;
         } else {
             ret = 0;
         }
         s->poll = 0;
     } else {
         if (addr == 0) {
             if (s->read_reg_select) {
                 ret = s->isr;
             } else {
                 ret = s->irr;
             }
         } else {
             ret = s->imr;
         }
     }
     trace_pic_ioport_read(s->master, addr, ret);
     return ret;
 }

 int pic_get_output(PICCommonState *s)
 {
     return (pic_get_irq(s) >= 0);
 }

 static void elcr_ioport_write(void *opaque, hwaddr addr,
                               uint64_t val, unsigned size)
 {
     PICCommonState *s = opaque;
     s->elcr = val & s->elcr_mask;
 }

 static uint64_t elcr_ioport_read(void *opaque, hwaddr addr,
                                  unsigned size)
 {
     PICCommonState *s = opaque;
     return s->elcr;
 }

 static const MemoryRegionOps pic_base_ioport_ops = {
     .read = pic_ioport_read,
     .write = pic_ioport_write,
     .impl = {
         .min_access_size = 1,
         .max_access_size = 1,
     },
 };

 static const MemoryRegionOps pic_elcr_ioport_ops = {
     .read = elcr_ioport_read,
     .write = elcr_ioport_write,
     .impl = {
         .min_access_size = 1,
         .max_access_size = 1,
     },
 };

 static void pic_realize(DeviceState *dev, Error **errp)
 {
     PICCommonState *s = PIC_COMMON(dev);
     PICClass *pc = PIC_GET_CLASS(dev);

     memory_region_init_io(&s->base_io, OBJECT(s), &pic_base_ioport_ops, s,
                           "pic", 2);
     memory_region_init_io(&s->elcr_io, OBJECT(s), &pic_elcr_ioport_ops, s,
                           "elcr", 1);

     qdev_init_gpio_out(dev, s->int_out, ARRAY_SIZE(s->int_out));
     qdev_init_gpio_in(dev, pic_set_irq, 8);

     pc->parent_realize(dev, errp);
 }

 qemu_irq *i8259_init(ISABus *bus, qemu_irq parent_irq_in)
 {
     qemu_irq *irq_set;
     DeviceState *dev;
     ISADevice *isadev;
     int i;

     irq_set = g_new0(qemu_irq, ISA_NUM_IRQS);

     isadev = i8259_init_chip(TYPE_I8259, bus, true);
     dev = DEVICE(isadev);

     qdev_connect_gpio_out(dev, 0, parent_irq_in);
     for (i = 0 ; i < 8; i++) {
         irq_set[i] = qdev_get_gpio_in(dev, i);
     }

     isa_pic = PIC_COMMON(dev);

     isadev = i8259_init_chip(TYPE_I8259, bus, false);
     dev = DEVICE(isadev);

     qdev_connect_gpio_out(dev, 0, irq_set[2]);
     for (i = 0 ; i < 8; i++) {
         irq_set[i + 8] = qdev_get_gpio_in(dev, i);
     }

     slave_pic = PIC_COMMON(dev);

     return irq_set;
 }

 static void i8259_class_init(ObjectClass *klass, void *data)
 {
     PICClass *k = PIC_CLASS(klass);
     DeviceClass *dc = DEVICE_CLASS(klass);

     device_class_set_parent_realize(dc, pic_realize, &k->parent_realize);
     device_class_set_legacy_reset(dc, pic_reset);
 }

 static const TypeInfo i8259_info = {
     .name       = TYPE_I8259,
     .instance_size = sizeof(PICCommonState),
     .parent     = TYPE_PIC_COMMON,
     .class_init = i8259_class_init,
     .class_size = sizeof(PICClass),
 };

 static void pic_register_types(void)
 {
     type_register_static(&i8259_info);
 }

 type_init(pic_register_types)
	/*
	* QEMU 8259 interrupt controller emulation
	*
	* Copyright (c) 2003-2004 Fabrice Bellard
	*
	* Permission is hereby granted, free of charge, to any person obtaining a copy
	* of this software and associated documentation files (the "Software"), to deal
	* in the Software without restriction, including without limitation the rights
	* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
	* copies of the Software, and to permit persons to whom the Software is
	* furnished to do so, subject to the following conditions:
	*
	* The above copyright notice and this permission notice shall be included in
	* all copies or substantial portions of the Software.
	*
	* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
	* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
	* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
	* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
	* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
	* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
	* THE SOFTWARE.
	*/

	#include "qemu/osdep.h"
	#include "hw/intc/i8259.h"
	#include "hw/irq.h"
	#include "hw/isa/isa.h"
	#include "qemu/timer.h"
	#include "qemu/log.h"
	#include "hw/isa/i8259_internal.h"
	#include "trace.h"
	#include "qom/object.h"

	/* debug PIC */
	//#define DEBUG_PIC

	//#define DEBUG_IRQ_LATENCY

	#define TYPE_I8259 "isa-i8259"
	typedef struct PICClass PICClass;
	DECLARE_CLASS_CHECKERS(PICClass, PIC,
	TYPE_I8259)

	/**
	* PICClass:
	* @parent_realize: The parent's realizefn.
	*/
	struct PICClass {
	PICCommonClass parent_class;

	DeviceRealize parent_realize;
	};

	#ifdef DEBUG_IRQ_LATENCY
	static int64_t irq_time[16];
	#endif
	PICCommonState *isa_pic;
	static PICCommonState *slave_pic;

	/* return the highest priority found in mask (highest = smallest
	number). Return 8 if no irq */
	static int get_priority(PICCommonState *s, int mask)
	{
	int priority;

	if (mask == 0) {
	return 8;
	}
	priority = 0;
	while ((mask & (1 << ((priority + s->priority_add) & 7))) == 0) {
	priority++;
	}
	return priority;
	}

	/* return the pic wanted interrupt. return -1 if none */
	static int pic_get_irq(PICCommonState *s)
	{
	int mask, cur_priority, priority;

	mask = s->irr & ~s->imr;
	priority = get_priority(s, mask);
	if (priority == 8) {
	return -1;
	}
	/* compute current priority. If special fully nested mode on the
	master, the IRQ coming from the slave is not taken into account
	for the priority computation. */
	mask = s->isr;
	if (s->special_mask) {
	mask &= ~s->imr;
	}
	if (s->special_fully_nested_mode && s->master) {
	mask &= ~(1 << 2);
	}
	cur_priority = get_priority(s, mask);
	if (priority < cur_priority) {
	/* higher priority found: an irq should be generated */
	return (priority + s->priority_add) & 7;
	} else {
	return -1;
	}
	}

	/* Update INT output. Must be called every time the output may have changed. */
	static void pic_update_irq(PICCommonState *s)
	{
	int irq;

	irq = pic_get_irq(s);
	if (irq >= 0) {
	trace_pic_update_irq(s->master, s->imr, s->irr, s->priority_add);
	qemu_irq_raise(s->int_out[0]);
	} else {
	qemu_irq_lower(s->int_out[0]);
	}
	}

	/* set irq level. If an edge is detected, then the IRR is set to 1 */
	static void pic_set_irq(void *opaque, int irq, int level)
	{
	PICCommonState *s = opaque;
	int mask = 1 << irq;
	int irq_index = s->master ? irq : irq + 8;

	trace_pic_set_irq(s->master, irq, level);
	pic_stat_update_irq(irq_index, level);

	#ifdef DEBUG_IRQ_LATENCY
	if (level) {
	irq_time[irq_index] = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL);
	}
	#endif

	if (s->ltim \|\| (s->elcr & mask)) {
	/* level triggered */
	if (level) {
	s->irr \|= mask;
	s->last_irr \|= mask;
	} else {
	s->irr &= ~mask;
	s->last_irr &= ~mask;
	}
	} else {
	/* edge triggered */
	if (level) {
	if ((s->last_irr & mask) == 0) {
	s->irr \|= mask;
	}
	s->last_irr \|= mask;
	} else {
	s->last_irr &= ~mask;
	}
	}
	pic_update_irq(s);
	}

	/* acknowledge interrupt 'irq' */
	static void pic_intack(PICCommonState *s, int irq)
	{
	if (s->auto_eoi) {
	if (s->rotate_on_auto_eoi) {
	s->priority_add = (irq + 1) & 7;
	}
	} else {
	s->isr \|= (1 << irq);
	}
	/* We don't clear a level sensitive interrupt here */
	if (!s->ltim && !(s->elcr & (1 << irq))) {
	s->irr &= ~(1 << irq);
	}
	pic_update_irq(s);
	}

	int pic_read_irq(PICCommonState *s)
	{
	int irq, intno;

	irq = pic_get_irq(s);
	if (irq >= 0) {
	int irq2;

	if (irq == 2) {
	irq2 = pic_get_irq(slave_pic);
	if (irq2 >= 0) {
	pic_intack(slave_pic, irq2);
	} else {
	/* spurious IRQ on slave controller */
	irq2 = 7;
	}
	intno = slave_pic->irq_base + irq2;
	pic_intack(s, irq);
	irq = irq2 + 8;
	} else {
	intno = s->irq_base + irq;
	pic_intack(s, irq);
	}
	} else {
	/* spurious IRQ on host controller */
	irq = 7;
	intno = s->irq_base + irq;
	}

	#ifdef DEBUG_IRQ_LATENCY
	printf("IRQ%d latency=%0.3fus\n",
	irq,
	(double)(qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL) -
	irq_time[irq]) * 1000000.0 / NANOSECONDS_PER_SECOND);
	#endif

	trace_pic_interrupt(irq, intno);
	return intno;
	}

	static void pic_init_reset(PICCommonState *s)
	{
	pic_reset_common(s);
	pic_update_irq(s);
	}

	static void pic_reset(DeviceState *dev)
	{
	PICCommonState *s = PIC_COMMON(dev);

	s->elcr = 0;
	s->ltim = 0;
	pic_init_reset(s);
	}

	static void pic_ioport_write(void *opaque, hwaddr addr64,
	uint64_t val64, unsigned size)
	{
	PICCommonState *s = opaque;
	uint32_t addr = addr64;
	uint32_t val = val64;
	int priority, cmd, irq;

	trace_pic_ioport_write(s->master, addr, val);

	if (addr == 0) {
	if (val & 0x10) {
	pic_init_reset(s);
	s->init_state = 1;
	s->init4 = val & 1;
	s->single_mode = val & 2;
	s->ltim = val & 8;
	} else if (val & 0x08) {
	if (val & 0x04) {
	s->poll = 1;
	}
	if (val & 0x02) {
	s->read_reg_select = val & 1;
	}
	if (val & 0x40) {
	s->special_mask = (val >> 5) & 1;
	}
	} else {
	cmd = val >> 5;
	switch (cmd) {
	case 0:
	case 4:
	s->rotate_on_auto_eoi = cmd >> 2;
	break;
	case 1: /* end of interrupt */
	case 5:
	priority = get_priority(s, s->isr);
	if (priority != 8) {
	irq = (priority + s->priority_add) & 7;
	s->isr &= ~(1 << irq);
	if (cmd == 5) {
	s->priority_add = (irq + 1) & 7;
	}
	pic_update_irq(s);
	}
	break;
	case 3:
	irq = val & 7;
	s->isr &= ~(1 << irq);
	pic_update_irq(s);
	break;
	case 6:
	s->priority_add = (val + 1) & 7;
	pic_update_irq(s);
	break;
	case 7:
	irq = val & 7;
	s->isr &= ~(1 << irq);
	s->priority_add = (irq + 1) & 7;
	pic_update_irq(s);
	break;
	default:
	/* no operation */
	break;
	}
	}
	} else {
	switch (s->init_state) {
	case 0:
	/* normal mode */
	s->imr = val;
	pic_update_irq(s);
	break;
	case 1:
	s->irq_base = val & 0xf8;
	s->init_state = s->single_mode ? (s->init4 ? 3 : 0) : 2;
	break;
	case 2:
	if (s->init4) {
	s->init_state = 3;
	} else {
	s->init_state = 0;
	}
	break;
	case 3:
	s->special_fully_nested_mode = (val >> 4) & 1;
	s->auto_eoi = (val >> 1) & 1;
	s->init_state = 0;
	break;
	}
	}
	}

	static uint64_t pic_ioport_read(void *opaque, hwaddr addr,
	unsigned size)
	{
	PICCommonState *s = opaque;
	int ret;

	if (s->poll) {
	ret = pic_get_irq(s);
	if (ret >= 0) {
	pic_intack(s, ret);
	ret \|= 0x80;
	} else {
	ret = 0;
	}
	s->poll = 0;
	} else {
	if (addr == 0) {
	if (s->read_reg_select) {
	ret = s->isr;
	} else {
	ret = s->irr;
	}
	} else {
	ret = s->imr;
	}
	}
	trace_pic_ioport_read(s->master, addr, ret);
	return ret;
	}

	int pic_get_output(PICCommonState *s)
	{
	return (pic_get_irq(s) >= 0);
	}

	static void elcr_ioport_write(void *opaque, hwaddr addr,
	uint64_t val, unsigned size)
	{
	PICCommonState *s = opaque;
	s->elcr = val & s->elcr_mask;
	}

	static uint64_t elcr_ioport_read(void *opaque, hwaddr addr,
	unsigned size)
	{
	PICCommonState *s = opaque;
	return s->elcr;
	}

	static const MemoryRegionOps pic_base_ioport_ops = {
	.read = pic_ioport_read,
	.write = pic_ioport_write,
	.impl = {
	.min_access_size = 1,
	.max_access_size = 1,
	},
	};

	static const MemoryRegionOps pic_elcr_ioport_ops = {
	.read = elcr_ioport_read,
	.write = elcr_ioport_write,
	.impl = {
	.min_access_size = 1,
	.max_access_size = 1,
	},
	};

	static void pic_realize(DeviceState dev, Error *errp)
	{
	PICCommonState *s = PIC_COMMON(dev);
	PICClass *pc = PIC_GET_CLASS(dev);

	memory_region_init_io(&s->base_io, OBJECT(s), &pic_base_ioport_ops, s,
	"pic", 2);
	memory_region_init_io(&s->elcr_io, OBJECT(s), &pic_elcr_ioport_ops, s,
	"elcr", 1);

	qdev_init_gpio_out(dev, s->int_out, ARRAY_SIZE(s->int_out));
	qdev_init_gpio_in(dev, pic_set_irq, 8);

	pc->parent_realize(dev, errp);
	}

	qemu_irq i8259_init(ISABus bus, qemu_irq parent_irq_in)
	{
	qemu_irq *irq_set;
	DeviceState *dev;
	ISADevice *isadev;
	int i;

	irq_set = g_new0(qemu_irq, ISA_NUM_IRQS);

	isadev = i8259_init_chip(TYPE_I8259, bus, true);
	dev = DEVICE(isadev);

	qdev_connect_gpio_out(dev, 0, parent_irq_in);
	for (i = 0 ; i < 8; i++) {
	irq_set[i] = qdev_get_gpio_in(dev, i);
	}

	isa_pic = PIC_COMMON(dev);

	isadev = i8259_init_chip(TYPE_I8259, bus, false);
	dev = DEVICE(isadev);

	qdev_connect_gpio_out(dev, 0, irq_set[2]);
	for (i = 0 ; i < 8; i++) {
	irq_set[i + 8] = qdev_get_gpio_in(dev, i);
	}

	slave_pic = PIC_COMMON(dev);

	return irq_set;
	}

	static void i8259_class_init(ObjectClass klass, void data)
	{
	PICClass *k = PIC_CLASS(klass);
	DeviceClass *dc = DEVICE_CLASS(klass);

	device_class_set_parent_realize(dc, pic_realize, &k->parent_realize);
	device_class_set_legacy_reset(dc, pic_reset);
	}

	static const TypeInfo i8259_info = {
	.name = TYPE_I8259,
	.instance_size = sizeof(PICCommonState),
	.parent = TYPE_PIC_COMMON,
	.class_init = i8259_class_init,
	.class_size = sizeof(PICClass),
	};

	static void pic_register_types(void)
	{
	type_register_static(&i8259_info);
	}

	type_init(pic_register_types)