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

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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: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20180220180325.29818-13-peter.maydell@linaro.org
This commit is contained in:
Peter Maydell 2018-03-02 10:45:38 +00:00
parent 4a151677a8
commit 5edb1b3fa9
4 changed files with 150 additions and 1 deletions
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89
hw/core/split-irq.c Normal file
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/*
* 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)