On Fri, 24 Oct 2025, Mark Cave-Ayland wrote:
On 23/10/2025 16:26, BALATON Zoltan wrote:
Export memory regions as sysbus mmio regions and let the board code
map them similar to how it is done in grackle. While at it rename
raven_pcihost_realizefn to raven_pcihost_realize.

Signed-off-by: BALATON Zoltan <[email protected]>
Reviewed-by: Philippe Mathieu-Daudé <[email protected]>
---
  hw/pci-host/raven.c | 38 +++++++++++++-------------------------
  hw/ppc/prep.c       | 10 ++++++++--
  2 files changed, 21 insertions(+), 27 deletions(-)

diff --git a/hw/pci-host/raven.c b/hw/pci-host/raven.c
index ebf0c511dc..1e36a637a6 100644
--- a/hw/pci-host/raven.c
+++ b/hw/pci-host/raven.c
@@ -49,8 +49,6 @@ struct PREPPCIState {
      AddressSpace bm_as;
  };
-#define PCI_IO_BASE_ADDR 0x80000000 /* Physical address on main bus */
-
  static inline uint32_t raven_idsel_to_addr(hwaddr addr)
  {
      return (ctz16(addr >> 11) << 11) | (addr & 0x7ff);
@@ -170,7 +168,7 @@ static void raven_change_gpio(void *opaque, int n, int level)
      memory_region_set_enabled(&s->pci_discontiguous_io, !!level);
  }
  -static void raven_pcihost_realizefn(DeviceState *d, Error **errp)
+static void raven_pcihost_realize(DeviceState *d, Error **errp)
  {
      SysBusDevice *dev = SYS_BUS_DEVICE(d);
      PCIHostState *h = PCI_HOST_BRIDGE(dev);
@@ -180,7 +178,18 @@ static void raven_pcihost_realizefn(DeviceState *d, Error **errp)
        qdev_init_gpio_in(d, raven_change_gpio, 1);
  +    memory_region_init(&s->pci_io, o, "pci-io", 0x3f800000);
+    memory_region_init_io(&s->pci_discontiguous_io, o,
+                          &raven_io_ops, &s->pci_io,
+                          "pci-discontiguous-io", 8 * MiB);
+    memory_region_set_enabled(&s->pci_discontiguous_io, false);
+    memory_region_init(&s->pci_memory, o, "pci-memory", 0x3f000000);
+
+    sysbus_init_mmio(dev, &s->pci_io);
+    sysbus_init_mmio(dev, &s->pci_discontiguous_io);
+    sysbus_init_mmio(dev, &s->pci_memory);
      sysbus_init_irq(dev, &s->irq);
+
      h->bus = pci_register_root_bus(d, NULL, raven_set_irq, raven_map_irq,
&s->irq, &s->pci_memory, &s->pci_io, 0, 1,
                                     TYPE_PCI_BUS);
@@ -219,32 +228,12 @@ static void raven_pcihost_realizefn(DeviceState *d, Error **errp)
      pci_setup_iommu(h->bus, &raven_iommu_ops, s);
  }
  -static void raven_pcihost_initfn(Object *obj)
-{
-    PREPPCIState *s = RAVEN_PCI_HOST_BRIDGE(obj);
-    MemoryRegion *address_space_mem = get_system_memory();
-
-    memory_region_init(&s->pci_io, obj, "pci-io", 0x3f800000);
-    memory_region_init_io(&s->pci_discontiguous_io, obj,
-                          &raven_io_ops, &s->pci_io,
-                          "pci-discontiguous-io", 8 * MiB);
-    memory_region_init(&s->pci_memory, obj, "pci-memory", 0x3f000000);
-
-    /* CPU address space */
-    memory_region_add_subregion(address_space_mem, PCI_IO_BASE_ADDR,
-                                &s->pci_io);
- memory_region_add_subregion_overlap(address_space_mem, PCI_IO_BASE_ADDR,
-                                        &s->pci_discontiguous_io, 1);
-    memory_region_set_enabled(&s->pci_discontiguous_io, false);
- memory_region_add_subregion(address_space_mem, 0xc0000000, &s->pci_memory);
-}
-
static void raven_pcihost_class_init(ObjectClass *klass, const void *data)
  {
      DeviceClass *dc = DEVICE_CLASS(klass);
        set_bit(DEVICE_CATEGORY_BRIDGE, dc->categories);
-    dc->realize = raven_pcihost_realizefn;
+    dc->realize = raven_pcihost_realize;
      dc->fw_name = "pci";
  }
  @@ -278,7 +267,6 @@ static const TypeInfo raven_types[] = {
          .name = TYPE_RAVEN_PCI_HOST_BRIDGE,
          .parent = TYPE_PCI_HOST_BRIDGE,
          .instance_size = sizeof(PREPPCIState),
-        .instance_init = raven_pcihost_initfn,
          .class_init = raven_pcihost_class_init,
      },
      {
diff --git a/hw/ppc/prep.c b/hw/ppc/prep.c
index 816455d289..973d2fb7eb 100644
--- a/hw/ppc/prep.c
+++ b/hw/ppc/prep.c
@@ -53,8 +53,11 @@
    #define CFG_ADDR 0xf0000510
  -#define KERNEL_LOAD_ADDR 0x01000000
-#define INITRD_LOAD_ADDR 0x01800000
+#define KERNEL_LOAD_ADDR  0x01000000
+#define INITRD_LOAD_ADDR  0x01800000
+
+#define PCI_IO_BASE_ADDR  0x80000000
+#define PCI_MEM_BASE_ADDR 0xc0000000
    #define BIOS_ADDR         0xfff00000
  #define BIOS_SIZE         (1 * MiB)
@@ -293,6 +296,9 @@ static void ibm_40p_init(MachineState *machine)
      pcihost = SYS_BUS_DEVICE(dev);
      object_property_add_child(qdev_get_machine(), "raven", OBJECT(dev));
      sysbus_realize_and_unref(pcihost, &error_fatal);
+    sysbus_mmio_map(pcihost, 0, PCI_IO_BASE_ADDR);
+    sysbus_mmio_map_overlap(pcihost, 1, PCI_IO_BASE_ADDR, 1);
+    sysbus_mmio_map(pcihost, 2, PCI_MEM_BASE_ADDR);
      pci_bus = PCI_BUS(qdev_get_child_bus(dev, "pci.0"));
      if (!pci_bus) {
          error_report("could not create PCI host controller");

In general the expectation is that memory regions should be initialised in the _init() function, unless they depend upon a property in which case they should be initialised in the _realize() function. Why do you feel this needs to be different?

Is any of it needed before realize? If not why have an init method at all? As shown here this works perfectly without one and is more comprehensible that way for people reading it without deep knowledge about Qdev. In general I think simple devices only need a realize method and the init method is rarely needed, e.g. if there are some child objects that need to be init for passing properties that can be set before realize or similar unusual cases but for most classes init is not needed at all. I only want to keep what's necessary and remove everything that's not needed. I think that makes the device model easier to understand.

Regards,
BALATON Zoltan

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