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

[Bernhard Beschow]

Am 8. Januar 2025 09:25:28 UTC schrieb Bernhard Beschow <shentey@gmail.com>:
>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

As pointed out by David, this device is redundant to TYPE_OR_IRQ. I'll drop it 
in v2.

Best regards,
Bernhard

>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.
>+ *
>+ * 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'))