acpi: pc: isa bridge: use AcpiDevAmlIf interface to build ISA device descriptors

replaces ad-hoc build_isa_devices_aml() with generic AcpiDevAmlIf
way to build bridge AML including all devices that are attached to
its ISA bus.

Later when PCI is converted to AcpiDevAmlIf, build_piix4_isa_bridge()
will also be dropped since PCI parts itself will take care of
building device prologue/epilogue AML for each enumerated PCI
device.

Expected AML change is contextual, where ISA devices are moved
from separately declared _SB.PCI0.ISA scope , directly under
Device(ISA) node.

Signed-off-by: Igor Mammedov <imammedo@redhat.com>
Acked-by: Gerd Hoffmann <kraxel@redhat.com>
Message-Id: <20220608135340.3304695-20-imammedo@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

hw/i386/acpi-build.c

@@ -1280,15 +1280,22 @@ static void build_piix4_isa_bridge(Aml *table)
 {
     Aml *dev;
     Aml *scope;
+    Object *obj;
+    bool ambiguous;
+
+    /*
+     * temporarily fish out isa bridge, build_piix4_isa_bridge() will be dropped
+     * once PCI is converted to AcpiDevAmlIf and would be ble to generate
+     * AML for bridge itself
+     */
+    obj = object_resolve_path_type("", TYPE_PIIX3_PCI_DEVICE, &ambiguous);
+    assert(obj && !ambiguous);
 
     scope =  aml_scope("_SB.PCI0");
     dev = aml_device("ISA");
     aml_append(dev, aml_name_decl("_ADR", aml_int(0x00010000)));
 
-    /* PIIX PCI to ISA irq remapping */
+    call_dev_aml_func(DEVICE(obj), dev);
-    aml_append(dev, aml_operation_region("P40C", AML_PCI_CONFIG,
-                                         aml_int(0x60), 0x04));
-
     aml_append(scope, dev);
     aml_append(table, scope);
 }
@@ -1476,7 +1483,6 @@ build_dsdt(GArray *table_data, BIOSLinker *linker,
             build_hpet_aml(dsdt);
         }
         build_piix4_isa_bridge(dsdt);
-        build_isa_devices_aml(dsdt);
         if (pm->pcihp_bridge_en || pm->pcihp_root_en) {
             build_x86_acpi_pci_hotplug(dsdt, pm->pcihp_io_base);
         }

hw/isa/piix3.c

@@ -32,6 +32,7 @@
 #include "sysemu/reset.h"
 #include "sysemu/runstate.h"
 #include "migration/vmstate.h"
+#include "hw/acpi/acpi_aml_interface.h"
 
 #define XEN_PIIX_NUM_PIRQS      128ULL
 
@@ -286,10 +287,24 @@ static void piix3_realize(PCIDevice *dev, Error **errp)
     qemu_register_reset(piix3_reset, d);
 }
 
+static void build_pci_isa_aml(AcpiDevAmlIf *adev, Aml *scope)
+{
+    BusChild *kid;
+    BusState *bus = qdev_get_child_bus(DEVICE(adev), "isa.0");
+
+    /* PIIX PCI to ISA irq remapping */
+    aml_append(scope, aml_operation_region("P40C", AML_PCI_CONFIG,
+                                         aml_int(0x60), 0x04));
+    QTAILQ_FOREACH(kid, &bus->children, sibling) {
+        call_dev_aml_func(DEVICE(kid->child), scope);
+    }
+}
+
 static void pci_piix3_class_init(ObjectClass *klass, void *data)
 {
     DeviceClass *dc = DEVICE_CLASS(klass);
     PCIDeviceClass *k = PCI_DEVICE_CLASS(klass);
+    AcpiDevAmlIfClass *adevc = ACPI_DEV_AML_IF_CLASS(klass);
 
     dc->desc        = "ISA bridge";
     dc->vmsd        = &vmstate_piix3;
@@ -304,6 +319,7 @@ static void pci_piix3_class_init(ObjectClass *klass, void *data)
      * pc_piix.c's pc_init1()
      */
     dc->user_creatable = false;
+    adevc->build_dev_aml = build_pci_isa_aml;
 }
 
 static const TypeInfo piix3_pci_type_info = {
@@ -314,6 +330,7 @@ static const TypeInfo piix3_pci_type_info = {
     .class_init = pci_piix3_class_init,
     .interfaces = (InterfaceInfo[]) {
         { INTERFACE_CONVENTIONAL_PCI_DEVICE },
+        { TYPE_ACPI_DEV_AML_IF },
         { },
     },
 };