pcihp: drop pcihp_bridge_en dependency when composing PCNT method

 .. and use only BSEL presence to decide on how PCNT should be composed.
That simplifies possible combinations to consider, but mainly it makes
PCIHP AML be governed only by BSEL, which is property of PCIBus
(aka part of bridge) and as result it opens possibility to convert
build_append_pci_bus_devices() into AcpiDevAmlIf::build_dev_aml
callback to make bridges self describing.

PS:
used approach leaves unused PCNT, when ACPI hotplug is completely
disabled but that's harmless and followup commits will get rid of
it later.

     Scope (PCI0)
           ...
           Method (PCNT, 0, NotSerialized)
            {
            }
           ...
     }

Signed-off-by: Igor Mammedov <imammedo@redhat.com>
Message-Id: <20230112140312.3096331-19-imammedo@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

diff --git a/hw/i386/acpi-build.c b/hw/i386/acpi-build.c
index 1c51ab01fcba5b197d3db5d415beca2630b2e7cb..27f2cc4180400c633037f6548c1d83fbe3eee1f0 100644 (file)
--- a/hw/i386/acpi-build.c
+++ b/hw/i386/acpi-build.c
@@ -494,39 +494,34 @@ static void build_append_pci_bus_devices(Aml *parent_scope, PCIBus *bus,
         aml_append(parent_scope, notify_method);
     }
 
-    /* Append PCNT method to notify about events on local and child buses.
-     * Add this method for root bus only when hotplug is enabled since DSDT
-     * expects it.
+    /*
+     * Append PCNT method to notify about events on local and child buses.
      */
-    if (bsel || pcihp_bridge_en) {
-        method = aml_method("PCNT", 0, AML_NOTSERIALIZED);
-
-        /* If bus supports hotplug select it and notify about local events */
-        if (bsel) {
-            uint64_t bsel_val = qnum_get_uint(qobject_to(QNum, bsel));
+    method = aml_method("PCNT", 0, AML_NOTSERIALIZED);
 
-            aml_append(method, aml_store(aml_int(bsel_val), aml_name("BNUM")));
-            aml_append(method, aml_call2("DVNT", aml_name("PCIU"),
-                                         aml_int(1))); /* Device Check */
-            aml_append(method, aml_call2("DVNT", aml_name("PCID"),
-                                         aml_int(3))); /* Eject Request */
-        }
+    /* If bus supports hotplug select it and notify about local events */
+    if (bsel) {
+        uint64_t bsel_val = qnum_get_uint(qobject_to(QNum, bsel));
 
-        /* Notify about child bus events in any case */
-        if (pcihp_bridge_en) {
-            QLIST_FOREACH(sec, &bus->child, sibling) {
-                if (pci_bus_is_root(sec) ||
-                    !object_property_find(OBJECT(sec), ACPI_PCIHP_PROP_BSEL)) {
-                    continue;
-                }
+        aml_append(method, aml_store(aml_int(bsel_val), aml_name("BNUM")));
+        aml_append(method, aml_call2("DVNT", aml_name("PCIU"),
+                                     aml_int(1))); /* Device Check */
+        aml_append(method, aml_call2("DVNT", aml_name("PCID"),
+                                     aml_int(3))); /* Eject Request */
+    }
 
-                aml_append(method, aml_name("^S%.02X.PCNT",
-                                            sec->parent_dev->devfn));
-            }
+    /* Notify about child bus events in any case */
+    QLIST_FOREACH(sec, &bus->child, sibling) {
+        if (pci_bus_is_root(sec) ||
+            !object_property_find(OBJECT(sec), ACPI_PCIHP_PROP_BSEL)) {
+            continue;
         }
 
-        aml_append(parent_scope, method);
+        aml_append(method, aml_name("^S%.02X.PCNT", sec->parent_dev->devfn));
     }
+
+    aml_append(parent_scope, method);
+
     qobject_unref(bsel);
 }