Re: [PATCH 04/14] hw/core: Introduce TYPE_SHARED_IRQ

[Bernhard Beschow]

Am 8. Januar 2025 13:53:02 UTC schrieb BALATON Zoltan <balaton@eik.bme.hu>:
>On Wed, 8 Jan 2025, Bernhard Beschow wrote:
>> Signed-off-by: Bernhard Beschow <shentey@gmail.com>
>> ---
>> include/hw/core/shared-irq.h | 39 ++++++++++++++++
>> hw/core/shared-irq.c         | 88 ++++++++++++++++++++++++++++++++++++
>> hw/core/Kconfig              |  3 ++
>> hw/core/meson.build          |  1 +
>> 4 files changed, 131 insertions(+)
>> create mode 100644 include/hw/core/shared-irq.h
>> create mode 100644 hw/core/shared-irq.c
>> 
>> diff --git a/include/hw/core/shared-irq.h b/include/hw/core/shared-irq.h
>> new file mode 100644
>> index 0000000000..803c303dd0
>> --- /dev/null
>> +++ b/include/hw/core/shared-irq.h
>> @@ -0,0 +1,39 @@
>> +/*
>> + * IRQ sharing device.
>> + *
>> + * Copyright (c) 2025 Bernhard Beschow <shentey@gmail.com>
>> + *
>> + * SPDX-License-Identifier: GPL-2.0-or-later
>> + */
>> +
>> +/*
>> + * This is a simple device which has one GPIO output line and multiple GPIO
>> + * input lines. The output line is active if at least one of the input 
>> lines is.
>
>How is this different from TYPE_OR_IRQ. Also or-irq.h is in 
>include/hw/or-irq.h not in include/hw/core/ where split-irq.h is

I missed exactly that.

> so maybe these could all be moved to one place for consistency? Or-irq also 
> has a reset method, do you need one in this device?

TYPE_OR_IRQ should be used instead. The next iteration will use it and this 
patch will be dropped.

Best regards,
Bernhard

>
>Regards,
>BALATON Zoltan
>
>> + *
>> + * QEMU interface:
>> + *  + N unnamed GPIO inputs: the input lines
>> + *  + one unnamed GPIO output: the output line
>> + *  + QOM property "num-lines": sets the number of input lines
>> + */
>> +#ifndef HW_SHARED_IRQ_H
>> +#define HW_SHARED_IRQ_H
>> +
>> +#include "hw/sysbus.h"
>> +#include "qom/object.h"
>> +
>> +#define TYPE_SHARED_IRQ "shared-irq"
>> +
>> +#define MAX_SHARED_LINES 16
>> +
>> +
>> +OBJECT_DECLARE_SIMPLE_TYPE(SharedIRQ, SHARED_IRQ)
>> +
>> +struct SharedIRQ {
>> +    DeviceState parent_obj;
>> +
>> +    qemu_irq out_irq;
>> +    uint16_t irq_states;
>> +    uint8_t num_lines;
>> +};
>> +
>> +#endif
>> diff --git a/hw/core/shared-irq.c b/hw/core/shared-irq.c
>> new file mode 100644
>> index 0000000000..b2a4ea4a66
>> --- /dev/null
>> +++ b/hw/core/shared-irq.c
>> @@ -0,0 +1,88 @@
>> +/*
>> + * IRQ sharing device.
>> + *
>> + * Copyright (c) 2025 Bernhard Beschow <shentey@gmail.com>
>> + *
>> + * SPDX-License-Identifier: GPL-2.0-or-later
>> + */
>> +
>> +#include "qemu/osdep.h"
>> +#include "hw/core/shared-irq.h"
>> +#include "hw/irq.h"
>> +#include "hw/qdev-properties.h"
>> +#include "qapi/error.h"
>> +#include "migration/vmstate.h"
>> +
>> +static void shared_irq_handler(void *opaque, int n, int level)
>> +{
>> +    SharedIRQ *s = opaque;
>> +    uint16_t mask = BIT(n);
>> +
>> +    if (level) {
>> +        s->irq_states |= mask;
>> +    } else {
>> +        s->irq_states &= ~mask;
>> +    }
>> +
>> +    qemu_set_irq(s->out_irq, !!s->irq_states);
>> +}
>> +
>> +static void shared_irq_init(Object *obj)
>> +{
>> +    SharedIRQ *s = SHARED_IRQ(obj);
>> +
>> +    qdev_init_gpio_out(DEVICE(s), &s->out_irq, 1);
>> +}
>> +
>> +static void shared_irq_realize(DeviceState *dev, Error **errp)
>> +{
>> +    SharedIRQ *s = SHARED_IRQ(dev);
>> +
>> +    if (s->num_lines < 1 || s->num_lines >= MAX_SHARED_LINES) {
>> +        error_setg(errp,
>> +                   "IRQ shared number of lines %d must be between 1 and %d",
>> +                   s->num_lines, MAX_SHARED_LINES);
>> +        return;
>> +    }
>> +
>> +    qdev_init_gpio_in(dev, shared_irq_handler, s->num_lines);
>> +}
>> +
>> +static const Property shared_irq_properties[] = {
>> +    DEFINE_PROP_UINT8("num-lines", SharedIRQ, num_lines, 1),
>> +};
>> +
>> +static const VMStateDescription shared_irq_vmstate = {
>> +    .name = TYPE_SHARED_IRQ,
>> +    .version_id = 1,
>> +    .minimum_version_id = 1,
>> +    .fields = (const VMStateField[]) {
>> +        VMSTATE_UINT16(irq_states, SharedIRQ),
>> +        VMSTATE_END_OF_LIST()
>> +    },
>> +};
>> +
>> +static void shared_irq_class_init(ObjectClass *klass, void *data)
>> +{
>> +    DeviceClass *dc = DEVICE_CLASS(klass);
>> +
>> +    /* No state to reset */
>> +    device_class_set_props(dc, shared_irq_properties);
>> +    dc->vmsd = &shared_irq_vmstate;
>> +    dc->realize = shared_irq_realize;
>> +
>> +    /* Reason: Needs to be wired up to work */
>> +    dc->user_creatable = false;
>> +}
>> +
>> +static const TypeInfo shared_irq_types[] = {
>> +    {
>> +       .name = TYPE_SHARED_IRQ,
>> +       .parent = TYPE_DEVICE,
>> +       .instance_size = sizeof(SharedIRQ),
>> +       .instance_init = shared_irq_init,
>> +       .class_init = shared_irq_class_init,
>> +    },
>> +};
>> +
>> +DEFINE_TYPES(shared_irq_types)
>> diff --git a/hw/core/Kconfig b/hw/core/Kconfig
>> index d1bdf765ee..ddff977963 100644
>> --- a/hw/core/Kconfig
>> +++ b/hw/core/Kconfig
>> @@ -32,6 +32,9 @@ config PLATFORM_BUS
>> config REGISTER
>>     bool
>> 
>> +config SHARED_IRQ
>> +    bool
>> +
>> config SPLIT_IRQ
>>     bool
>> 
>> diff --git a/hw/core/meson.build b/hw/core/meson.build
>> index ce9dfa3f4b..6b5bdc8ec7 100644
>> --- a/hw/core/meson.build
>> +++ b/hw/core/meson.build
>> @@ -21,6 +21,7 @@ system_ss.add(when: 'CONFIG_OR_IRQ', if_true: 
>> files('or-irq.c'))
>> system_ss.add(when: 'CONFIG_PLATFORM_BUS', if_true: files('platform-bus.c'))
>> system_ss.add(when: 'CONFIG_PTIMER', if_true: files('ptimer.c'))
>> system_ss.add(when: 'CONFIG_REGISTER', if_true: files('register.c'))
>> +system_ss.add(when: 'CONFIG_SHARED_IRQ', if_true: files('shared-irq.c'))
>> system_ss.add(when: 'CONFIG_SPLIT_IRQ', if_true: files('split-irq.c'))
>> system_ss.add(when: 'CONFIG_XILINX_AXI', if_true: files('stream.c'))
>> system_ss.add(when: 'CONFIG_PLATFORM_BUS', if_true: files('sysbus-fdt.c'))
>>