hw/pci-host/gpex-acpi: Use build_pci_host_bridge_osc_method

gpex build_host_bridge_osc() and x86 originated
build_pci_host_bridge_osc_method() are mostly identical.

In GPEX, SUPP is set to CDW2 but is not further used. CTRL
is same as Local0.

So let gpex code reuse build_pci_host_bridge_osc_method()
and remove build_host_bridge_osc().

Also add an imply ACPI_PCI clause along with
PCI_EXPRESS_GENERIC_BRIDGE to compile hw/acpi/pci.c
when its dependency is resolved (ie. CONFIG_ACPI_PCI).
This is requested to link qemu-system-mips64el.

The disassembled DSDT difference is given below:

  * Original Table Header:
  *     Signature        "DSDT"
- *     Length           0x00001A4F (6735)
+ *     Length           0x00001A35 (6709)
  *     Revision         0x02
- *     Checksum         0xBF
+ *     Checksum         0xDD
  *     OEM ID           "BOCHS "
  *     OEM Table ID     "BXPC    "
  *     OEM Revision     0x00000001 (1)
@@ -1849,27 +1849,26 @@ DefinitionBlock ("", "DSDT", 2, "BOCHS ", "BXPC    ", 0x00000001)
                 {
                     CreateDWordField (Arg3, 0x04, CDW2)
                     CreateDWordField (Arg3, 0x08, CDW3)
-                    SUPP = CDW2 /* \_SB_.PCI0._OSC.CDW2 */
-                    CTRL = CDW3 /* \_SB_.PCI0._OSC.CDW3 */
-                    CTRL &= 0x1F
+                    Local0 = CDW3 /* \_SB_.PCI0._OSC.CDW3 */
+                    Local0 &= 0x1F
                     If ((Arg1 != One))
                     {
                         CDW1 |= 0x08
                     }

-                    If ((CDW3 != CTRL))
+                    If ((CDW3 != Local0))
                     {
                         CDW1 |= 0x10
                     }

-                    CDW3 = CTRL /* \_SB_.PCI0.CTRL */
-                    Return (Arg3)
+                    CDW3 = Local0
                 }
                 Else
                 {
                     CDW1 |= 0x04
-                    Return (Arg3)
                 }
+
+                Return (Arg3)
             }

             Method (_DSM, 4, NotSerialized)  // _DSM: Device-Specific Method

Signed-off-by: Eric Auger <eric.auger@redhat.com>
Reviewed-by: Igor Mammedov <imammedo@redhat.com>
Reviewed-by: Jonathan Cameron <jonathan.cameron@huawei.com>
Message-Id: <20250714080639.2525563-10-eric.auger@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

2 files changed, 6 insertions, 57 deletions

diff --git a/hw/pci-host/Kconfig b/hw/pci-host/Kconfig
index 35c0415..9824fa1 100644
--- a/hw/pci-host/Kconfig
+++ b/hw/pci-host/Kconfig
@@ -54,6 +54,7 @@ config PCI_EXPRESS_Q35
 config PCI_EXPRESS_GENERIC_BRIDGE
     bool
     select PCI_EXPRESS
+    imply ACPI_PCI
 
 config PCI_EXPRESS_XILINX
     bool
diff --git a/hw/pci-host/gpex-acpi.c b/hw/pci-host/gpex-acpi.c
index 44737a8..952a0ac 100644
--- a/hw/pci-host/gpex-acpi.c
+++ b/hw/pci-host/gpex-acpi.c
@@ -1,5 +1,6 @@
 #include "qemu/osdep.h"
 #include "hw/acpi/aml-build.h"
+#include "hw/acpi/pci.h"
 #include "hw/pci-host/gpex.h"
 #include "hw/arm/virt.h"
 #include "hw/pci/pci_bus.h"
@@ -50,61 +51,7 @@ static void acpi_dsdt_add_pci_route_table(Aml *dev, uint32_t irq,
     }
 }
 
-static Aml *build_host_bridge_osc(bool enable_native_pcie_hotplug)
-{
-    Aml *method, *UUID, *ifctx, *ifctx1, *elsectx;
-    method = aml_method("_OSC", 4, AML_NOTSERIALIZED);
-    aml_append(method, aml_name_decl("SUPP", aml_int(0)));
-    aml_append(method, aml_name_decl("CTRL", aml_int(0)));
-    aml_append(method,
-        aml_create_dword_field(aml_arg(3), aml_int(0), "CDW1"));
-
-    /* PCI Firmware Specification 3.0
-     * 4.5.1. _OSC Interface for PCI Host Bridge Devices
-     * The _OSC interface for a PCI/PCI-X/PCI Express hierarchy is
-     * identified by the Universal Unique IDentifier (UUID)
-     * 33DB4D5B-1FF7-401C-9657-7441C03DD766
-     */
-    UUID = aml_touuid("33DB4D5B-1FF7-401C-9657-7441C03DD766");
-    ifctx = aml_if(aml_equal(aml_arg(0), UUID));
-    aml_append(ifctx,
-        aml_create_dword_field(aml_arg(3), aml_int(4), "CDW2"));
-    aml_append(ifctx,
-        aml_create_dword_field(aml_arg(3), aml_int(8), "CDW3"));
-    aml_append(ifctx, aml_store(aml_name("CDW2"), aml_name("SUPP")));
-    aml_append(ifctx, aml_store(aml_name("CDW3"), aml_name("CTRL")));
-
-    /*
-     * Allow OS control for SHPCHotplug, PME, AER, PCIeCapability,
-     * and PCIeHotplug depending on enable_native_pcie_hotplug
-     */
-    aml_append(ifctx, aml_and(aml_name("CTRL"),
-               aml_int(0x1E | (enable_native_pcie_hotplug ? 0x1 : 0x0)),
-               aml_name("CTRL")));
-
-    ifctx1 = aml_if(aml_lnot(aml_equal(aml_arg(1), aml_int(0x1))));
-    aml_append(ifctx1, aml_or(aml_name("CDW1"), aml_int(0x08),
-                              aml_name("CDW1")));
-    aml_append(ifctx, ifctx1);
-
-    ifctx1 = aml_if(aml_lnot(aml_equal(aml_name("CDW3"), aml_name("CTRL"))));
-    aml_append(ifctx1, aml_or(aml_name("CDW1"), aml_int(0x10),
-                              aml_name("CDW1")));
-    aml_append(ifctx, ifctx1);
-
-    aml_append(ifctx, aml_store(aml_name("CTRL"), aml_name("CDW3")));
-    aml_append(ifctx, aml_return(aml_arg(3)));
-    aml_append(method, ifctx);
-
-    elsectx = aml_else();
-    aml_append(elsectx, aml_or(aml_name("CDW1"), aml_int(4),
-                               aml_name("CDW1")));
-    aml_append(elsectx, aml_return(aml_arg(3)));
-    aml_append(method, elsectx);
-    return method;
-}
-
-static Aml *build_host_bridge_dsm(void)
+static Aml *build_pci_host_bridge_dsm_method(void)
 {
     Aml *method = aml_method("_DSM", 4, AML_NOTSERIALIZED);
     Aml *UUID, *ifctx, *ifctx1, *buf;
@@ -133,8 +80,9 @@ static void acpi_dsdt_add_host_bridge_methods(Aml *dev,
                                               bool enable_native_pcie_hotplug)
 {
     /* Declare an _OSC (OS Control Handoff) method */
-    aml_append(dev, build_host_bridge_osc(enable_native_pcie_hotplug));
-    aml_append(dev, build_host_bridge_dsm());
+    aml_append(dev,
+               build_pci_host_bridge_osc_method(enable_native_pcie_hotplug));
+    aml_append(dev, build_pci_host_bridge_dsm_method());
 }
 
 void acpi_dsdt_add_gpex(Aml *scope, struct GPEXConfig *cfg)