Signed-off-by: Bernhard Beschow <shen...@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 <shen...@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.
+ *
+ * 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 <shen...@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'))
--
2.47.1
