Commit 5edb1b3f authored by Peter Maydell's avatar Peter Maydell
Browse files

hw/core/split-irq: Device that splits IRQ lines 



In some board or SoC models it is necessary to split a qemu_irq line
so that one input can feed multiple outputs.  We currently have
qemu_irq_split() for this, but that has several deficiencies:
 * it can only handle splitting a line into two
 * it unavoidably leaks memory, so it can't be used
   in a device that can be deleted

Implement a qdev device that encapsulates splitting of IRQs, with a
configurable number of outputs.  (This is in some ways the inverse of
the TYPE_OR_IRQ device.)

Signed-off-by: default avatarPeter Maydell <peter.maydell@linaro.org>
Reviewed-by: default avatarRichard Henderson <richard.henderson@linaro.org>
Message-id: 20180220180325.29818-13-peter.maydell@linaro.org
parent 4a151677

hw/core/Makefile.objs

+1 −0
Original line number Diff line number Diff line
@@ -18,6 +18,7 @@ common-obj-$(CONFIG_FITLOADER) += loader-fit.o 
common-obj-$(CONFIG_SOFTMMU) += qdev-properties-system.o

common-obj-$(CONFIG_SOFTMMU) += register.o

common-obj-$(CONFIG_SOFTMMU) += or-irq.o

common-obj-$(CONFIG_SOFTMMU) += split-irq.o

common-obj-$(CONFIG_PLATFORM_BUS) += platform-bus.o



obj-$(CONFIG_SOFTMMU) += generic-loader.o

hw/core/split-irq.c

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+89 −0
Original line number Diff line number Diff line 
/*

 * IRQ splitter device.

 *

 * Copyright (c) 2018 Linaro Limited.

 * Written by Peter Maydell

 *

 * 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/core/split-irq.h"

#include "qapi/error.h"



static void split_irq_handler(void *opaque, int n, int level)

{

    SplitIRQ *s = SPLIT_IRQ(opaque);

    int i;



    for (i = 0; i < s->num_lines; i++) {

        qemu_set_irq(s->out_irq[i], level);

    }

}



static void split_irq_init(Object *obj)

{

    qdev_init_gpio_in(DEVICE(obj), split_irq_handler, 1);

}



static void split_irq_realize(DeviceState *dev, Error **errp)

{

    SplitIRQ *s = SPLIT_IRQ(dev);



    if (s->num_lines < 1 || s->num_lines >= MAX_SPLIT_LINES) {

        error_setg(errp,

                   "IRQ splitter number of lines %d is not between 1 and %d",

                   s->num_lines, MAX_SPLIT_LINES);

        return;

    }



    qdev_init_gpio_out(dev, s->out_irq, s->num_lines);

}



static Property split_irq_properties[] = {

    DEFINE_PROP_UINT16("num-lines", SplitIRQ, num_lines, 1),

    DEFINE_PROP_END_OF_LIST(),

};



static void split_irq_class_init(ObjectClass *klass, void *data)

{

    DeviceClass *dc = DEVICE_CLASS(klass);



    /* No state to reset or migrate */

    dc->props = split_irq_properties;

    dc->realize = split_irq_realize;



    /* Reason: Needs to be wired up to work */

    dc->user_creatable = false;

}



static const TypeInfo split_irq_type_info = {

   .name = TYPE_SPLIT_IRQ,

   .parent = TYPE_DEVICE,

   .instance_size = sizeof(SplitIRQ),

   .instance_init = split_irq_init,

   .class_init = split_irq_class_init,

};



static void split_irq_register_types(void)

{

    type_register_static(&split_irq_type_info);

}



type_init(split_irq_register_types)

include/hw/core/split-irq.h

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+57 −0
Original line number Diff line number Diff line 
/*

 * IRQ splitter device.

 *

 * Copyright (c) 2018 Linaro Limited.

 * Written by Peter Maydell

 *

 * 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.

 */



/* This is a simple device which has one GPIO input line and multiple

 * GPIO output lines. Any change on the input line is forwarded to all

 * of the outputs.

 *

 * QEMU interface:

 *  + one unnamed GPIO input: the input line

 *  + N unnamed GPIO outputs: the output lines

 *  + QOM property "num-lines": sets the number of output lines

 */

#ifndef HW_SPLIT_IRQ_H

#define HW_SPLIT_IRQ_H



#include "hw/irq.h"

#include "hw/sysbus.h"

#include "qom/object.h"



#define TYPE_SPLIT_IRQ "split-irq"



#define MAX_SPLIT_LINES 16



typedef struct SplitIRQ SplitIRQ;



#define SPLIT_IRQ(obj) OBJECT_CHECK(SplitIRQ, (obj), TYPE_SPLIT_IRQ)



struct SplitIRQ {

    DeviceState parent_obj;



    qemu_irq out_irq[MAX_SPLIT_LINES];

    uint16_t num_lines;

};



#endif

include/hw/irq.h

+3 −1
Original line number Diff line number Diff line
@@ -50,7 +50,9 @@ void qemu_free_irq(qemu_irq irq); 
/* Returns a new IRQ with opposite polarity.  */

qemu_irq qemu_irq_invert(qemu_irq irq);



/* Returns a new IRQ which feeds into both the passed IRQs */

/* Returns a new IRQ which feeds into both the passed IRQs.

 * It's probably better to use the TYPE_SPLIT_IRQ device instead.

 */

qemu_irq qemu_irq_split(qemu_irq irq1, qemu_irq irq2);



/* Returns a new IRQ set which connects 1:1 to another IRQ set, which