Demonstrate how to use nios2 VIC on a machine.
Introduce a new machine "10m50-ghrd-vic" which is based on "10m50-ghrd"
with a VIC attached and internal interrupt controller removed.

When VIC is present, irq0 connects the VIC to the cpu, intc_present
is set to false to disable the internal interrupt controller, and the
devices on the machine are attached to the VIC (and not directly to cpu).
To allow VIC update EIC fields, we set the "cpu" property of the VIC
with a reference to the nios2 cpu.

Signed-off-by: Amir Gonnen <amir.gonnen@neuroblade.ai>
---
 hw/nios2/10m50_devboard.c | 64 ++++++++++++++++++++++++++++++++++++---
 hw/nios2/Kconfig          |  1 +
 2 files changed, 61 insertions(+), 4 deletions(-)

diff --git a/hw/nios2/10m50_devboard.c b/hw/nios2/10m50_devboard.c
index 3d1205b8bd..9f62a2993f 100644
--- a/hw/nios2/10m50_devboard.c
+++ b/hw/nios2/10m50_devboard.c
@@ -36,10 +36,23 @@
 
 #include "boot.h"
 
+#define TYPE_NIOS2_MACHINE  MACHINE_TYPE_NAME("10m50-ghrd")
+typedef struct Nios2MachineClass Nios2MachineClass;
+DECLARE_OBJ_CHECKERS(MachineState, Nios2MachineClass,
+                     NIOS2_MACHINE, TYPE_NIOS2_MACHINE)
+
 #define BINARY_DEVICE_TREE_FILE    "10m50-devboard.dtb"
 
+struct Nios2MachineClass {
+    MachineClass parent_obj;
+
+    bool vic;
+};
+
 static void nios2_10m50_ghrd_init(MachineState *machine)
 {
+    Nios2MachineClass *nmc = NIOS2_MACHINE_GET_CLASS(machine);
+
     Nios2CPU *cpu;
     DeviceState *dev;
     MemoryRegion *address_space_mem = get_system_memory();
@@ -74,8 +87,24 @@ static void nios2_10m50_ghrd_init(MachineState *machine)
 
     /* Create CPU -- FIXME */
     cpu = NIOS2_CPU(cpu_create(TYPE_NIOS2_CPU));
-    for (i = 0; i < 32; i++) {
-        irq[i] = qdev_get_gpio_in_named(DEVICE(cpu), "IRQ", i);
+
+    if (nmc->vic) {
+        DeviceState *dev = qdev_new("nios2-vic");
+
+        object_property_set_link(OBJECT(dev), "cpu", OBJECT(cpu), &error_fatal);
+        sysbus_realize_and_unref(SYS_BUS_DEVICE(dev), &error_fatal);
+        cpu->intc_present = false;
+        qemu_irq cpu_irq = qdev_get_gpio_in_named(DEVICE(cpu), "IRQ", 0);
+        sysbus_connect_irq(SYS_BUS_DEVICE(dev), 0, cpu_irq);
+        for (int i = 0; i < 32; i++) {
+            irq[i] = qdev_get_gpio_in(dev, i);
+        }
+        MemoryRegion *dev_mr = sysbus_mmio_get_region(SYS_BUS_DEVICE(dev), 0);
+        memory_region_add_subregion(address_space_mem, 0x18002000, dev_mr);
+    } else {
+        for (i = 0; i < 32; i++) {
+            irq[i] = qdev_get_gpio_in_named(DEVICE(cpu), "IRQ", i);
+        }
     }
 
     /* Register: Altera 16550 UART */
@@ -105,11 +134,38 @@ static void nios2_10m50_ghrd_init(MachineState *machine)
                       BINARY_DEVICE_TREE_FILE, NULL);
 }
 
-static void nios2_10m50_ghrd_machine_init(struct MachineClass *mc)
+static void nios2_10m50_ghrd_machine_class_init(ObjectClass *oc, void *data)
 {
+    MachineClass *mc = MACHINE_CLASS(oc);
+    Nios2MachineClass *nmc = NIOS2_MACHINE_CLASS(oc);
     mc->desc = "Altera 10M50 GHRD Nios II design";
     mc->init = nios2_10m50_ghrd_init;
     mc->is_default = true;
+    nmc->vic = false;
 }
 
-DEFINE_MACHINE("10m50-ghrd", nios2_10m50_ghrd_machine_init);
+static void nios2_10m50_ghrd_vic_machine_class_init(ObjectClass *oc, void *data)
+{
+    MachineClass *mc = MACHINE_CLASS(oc);
+    Nios2MachineClass *nmc = NIOS2_MACHINE_CLASS(oc);
+    mc->desc = "Altera 10M50 GHRD Nios II design with VIC";
+    mc->init = nios2_10m50_ghrd_init;
+    mc->is_default = false;
+    nmc->vic = true;
+}
+
+static const TypeInfo nios_machine_types[] = {
+    {
+        .name          = MACHINE_TYPE_NAME("10m50-ghrd"),
+        .parent        = TYPE_MACHINE,
+        .class_size    = sizeof(Nios2MachineClass),
+        .class_init    = nios2_10m50_ghrd_machine_class_init,
+    }, {
+        .name          = MACHINE_TYPE_NAME("10m50-ghrd-vic"),
+        .parent        = TYPE_MACHINE,
+        .class_size    = sizeof(Nios2MachineClass),
+        .class_init    = nios2_10m50_ghrd_vic_machine_class_init,
+    }
+};
+
+DEFINE_TYPES(nios_machine_types)
diff --git a/hw/nios2/Kconfig b/hw/nios2/Kconfig
index b10ea640da..4748ae27b6 100644
--- a/hw/nios2/Kconfig
+++ b/hw/nios2/Kconfig
@@ -3,6 +3,7 @@ config NIOS2_10M50
     select NIOS2
     select SERIAL
     select ALTERA_TIMER
+    select NIOS2_VIC
 
 config NIOS2_GENERIC_NOMMU
     bool
-- 
2.25.1

On Thu, 3 Mar 2022 at 15:39, Amir Gonnen <amir.gonnen@neuroblade.ai> wrote:
>
> Demonstrate how to use nios2 VIC on a machine.
> Introduce a new machine "10m50-ghrd-vic" which is based on "10m50-ghrd"
> with a VIC attached and internal interrupt controller removed.
>
> When VIC is present, irq0 connects the VIC to the cpu, intc_present
> is set to false to disable the internal interrupt controller, and the
> devices on the machine are attached to the VIC (and not directly to cpu).
> To allow VIC update EIC fields, we set the "cpu" property of the VIC
> with a reference to the nios2 cpu.
>
> Signed-off-by: Amir Gonnen <amir.gonnen@neuroblade.ai>
> ---
>  hw/nios2/10m50_devboard.c | 64 ++++++++++++++++++++++++++++++++++++---
>  hw/nios2/Kconfig          |  1 +
>  2 files changed, 61 insertions(+), 4 deletions(-)

My remarks about this from the earlier version of the patchset still
stand:
 (1) if this isn't an actual config of the real hardware, then
presumably there aren't any guests which will run on it with the
VIC enabled
 (2) if we do want to do this, we should have a machine property
for "vic=true" rather than a complete new machine type

thanks
-- PMM