[PATCH 1/3] ArmPkg: add driver to force 64-bit MMIO BARs to be allocated above 4 GB

[Ard Biesheuvel <ard.biesheuvel@linaro.org>]

By default, the generic PciBusDxe driver uses the presence of a ROM BAR
as a hint that all MMIO BARs should be allocated in the 32-bit region,
even the ones that could be allocated above 4 GB. The reason is that
such a ROM BAR may contain code that runs in the context of a legacy
BIOS (i.e., a CSM), and allocating the 64-bit BARs above 4 GB may put
them out of reach.

Of course, none of this matters on ARM, and so we can unconditionally
override this decision. So take the OVMF implementation of the
IncompatiblePciDeviceSupportDxe driver, rip out the bits that care
about the presence of a legacy BIOS, and wire it up to the ArmPkg PCI
PCDs.

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
---
 ArmPkg/Drivers/IncompatiblePciDeviceSupportDxe/IncompatiblePciDeviceSupport.c   | 223 ++++++++++++++++++++
 ArmPkg/Drivers/IncompatiblePciDeviceSupportDxe/IncompatiblePciDeviceSupport.inf |  49 +++++
 2 files changed, 272 insertions(+)

diff --git a/ArmPkg/Drivers/IncompatiblePciDeviceSupportDxe/IncompatiblePciDeviceSupport.c b/ArmPkg/Drivers/IncompatiblePciDeviceSupportDxe/IncompatiblePciDeviceSupport.c
new file mode 100644
index 000000000000..3f2869f8f3c2
--- /dev/null
+++ b/ArmPkg/Drivers/IncompatiblePciDeviceSupportDxe/IncompatiblePciDeviceSupport.c
@@ -0,0 +1,223 @@
+/** @file
+  A simple DXE_DRIVER that causes the PCI Bus UEFI_DRIVER to allocate 64-bit
+  MMIO BARs above 4 GB, regardless of option ROM availability, conserving
+  32-bit MMIO aperture for 32-bit BARs.
+
+  Copyright (C) 2016, Red Hat, Inc.
+  Copyright (C) 2016, Linaro, Ltd.
+
+  This program and the accompanying materials are licensed and made available
+  under the terms and conditions of the BSD License which accompanies this
+  distribution. The full text of the license may be found at
+  http://opensource.org/licenses/bsd-license.php
+
+  THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS, WITHOUT
+  WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
+**/
+
+#include <IndustryStandard/Acpi10.h>
+#include <IndustryStandard/Pci22.h>
+
+#include <Library/DebugLib.h>
+#include <Library/MemoryAllocationLib.h>
+#include <Library/PcdLib.h>
+#include <Library/UefiBootServicesTableLib.h>
+
+#include <Protocol/IncompatiblePciDeviceSupport.h>
+
+//
+// The protocol interface this driver produces.
+//
+STATIC
+EFI_INCOMPATIBLE_PCI_DEVICE_SUPPORT_PROTOCOL    mIncompatiblePciDeviceSupport;
+
+//
+// Configuration template for the CheckDevice() protocol member function.
+//
+// Refer to Table 20 "ACPI 2.0 & 3.0 QWORD Address Space Descriptor Usage" in
+// the Platform Init 1.4a Spec, Volume 5.
+//
+// This structure is interpreted by the UpdatePciInfo() function in the edk2
+// PCI Bus UEFI_DRIVER.
+//
+#pragma pack (1)
+typedef struct {
+  EFI_ACPI_ADDRESS_SPACE_DESCRIPTOR AddressSpaceDesc;
+  EFI_ACPI_END_TAG_DESCRIPTOR       EndDesc;
+} MMIO64_PREFERENCE;
+#pragma pack ()
+
+STATIC CONST MMIO64_PREFERENCE mConfiguration = {
+  //
+  // AddressSpaceDesc
+  //
+  {
+    ACPI_ADDRESS_SPACE_DESCRIPTOR,                 // Desc
+    (UINT16)(                                      // Len
+      sizeof (EFI_ACPI_ADDRESS_SPACE_DESCRIPTOR) -
+      OFFSET_OF (
+        EFI_ACPI_ADDRESS_SPACE_DESCRIPTOR,
+        ResType
+        )
+      ),
+    ACPI_ADDRESS_SPACE_TYPE_MEM,                   // ResType
+    PCI_ACPI_UNUSED,                               // GenFlag
+    PCI_ACPI_UNUSED,                               // SpecificFlag
+    64,                                            // AddrSpaceGranularity:
+                                                   //   aperture selection hint
+                                                   //   for BAR allocation
+    PCI_ACPI_UNUSED,                               // AddrRangeMin
+    PCI_BAR_OLD_ALIGN,                             // AddrRangeMax:
+                                                   //   no special alignment
+                                                   //   for affected BARs
+    PCI_BAR_ALL,                                   // AddrTranslationOffset:
+                                                   //   hint covers all
+                                                   //   eligible BARs
+    PCI_BAR_NOCHANGE                               // AddrLen:
+                                                   //   use probed BAR size
+  },
+  //
+  // EndDesc
+  //
+  {
+    ACPI_END_TAG_DESCRIPTOR,                       // Desc
+    0                                              // Checksum: to be ignored
+  }
+};
+
+
+/**
+  Returns a list of ACPI resource descriptors that detail the special resource
+  configuration requirements for an incompatible PCI device.
+
+  Prior to bus enumeration, the PCI bus driver will look for the presence of
+  the EFI_INCOMPATIBLE_PCI_DEVICE_SUPPORT_PROTOCOL. Only one instance of this
+  protocol can be present in the system. For each PCI device that the PCI bus
+  driver discovers, the PCI bus driver calls this function with the device's
+  vendor ID, device ID, revision ID, subsystem vendor ID, and subsystem device
+  ID. If the VendorId, DeviceId, RevisionId, SubsystemVendorId, or
+  SubsystemDeviceId value is set to (UINTN)-1, that field will be ignored. The
+  ID values that are not (UINTN)-1 will be used to identify the current device.
+
+  This function will only return EFI_SUCCESS. However, if the device is an
+  incompatible PCI device, a list of ACPI resource descriptors will be returned
+  in Configuration. Otherwise, NULL will be returned in Configuration instead.
+  The PCI bus driver does not need to allocate memory for Configuration.
+  However, it is the PCI bus driver's responsibility to free it. The PCI bus
+  driver then can configure this device with the information that is derived
+  from this list of resource nodes, rather than the result of BAR probing.
+
+  Only the following two resource descriptor types from the ACPI Specification
+  may be used to describe the incompatible PCI device resource requirements:
+  - QWORD Address Space Descriptor (ACPI 2.0, section 6.4.3.5.1; also ACPI 3.0)
+  - End Tag (ACPI 2.0, section 6.4.2.8; also ACPI 3.0)
+
+  The QWORD Address Space Descriptor can describe memory, I/O, and bus number
+  ranges for dynamic or fixed resources. The configuration of a PCI root bridge
+  is described with one or more QWORD Address Space Descriptors, followed by an
+  End Tag. See the ACPI Specification for details on the field values.
+
+  @param[in]  This                Pointer to the
+                                  EFI_INCOMPATIBLE_PCI_DEVICE_SUPPORT_PROTOCOL
+                                  instance.
+
+  @param[in]  VendorId            A unique ID to identify the manufacturer of
+                                  the PCI device.  See the Conventional PCI
+                                  Specification 3.0 for details.
+
+  @param[in]  DeviceId            A unique ID to identify the particular PCI
+                                  device. See the Conventional PCI
+                                  Specification 3.0 for details.
+
+  @param[in]  RevisionId          A PCI device-specific revision identifier.
+                                  See the Conventional PCI Specification 3.0
+                                  for details.
+
+  @param[in]  SubsystemVendorId   Specifies the subsystem vendor ID. See the
+                                  Conventional PCI Specification 3.0 for
+                                  details.
+
+  @param[in]  SubsystemDeviceId   Specifies the subsystem device ID. See the
+                                  Conventional PCI Specification 3.0 for
+                                  details.
+
+  @param[out] Configuration       A list of ACPI resource descriptors that
+                                  detail the configuration requirement.
+
+  @retval EFI_SUCCESS   The function always returns EFI_SUCCESS.
+**/
+STATIC
+EFI_STATUS
+EFIAPI
+CheckDevice (
+  IN  EFI_INCOMPATIBLE_PCI_DEVICE_SUPPORT_PROTOCOL  *This,
+  IN  UINTN                                         VendorId,
+  IN  UINTN                                         DeviceId,
+  IN  UINTN                                         RevisionId,
+  IN  UINTN                                         SubsystemVendorId,
+  IN  UINTN                                         SubsystemDeviceId,
+  OUT VOID                                          **Configuration
+  )
+{
+  //
+  // Unlike the general description of this protocol member suggests, there is
+  // nothing incompatible about the PCI devices that we'll match here. We'll
+  // match all PCI devices, and generate exactly one QWORD Address Space
+  // Descriptor for each. That descriptor will instruct the PCI Bus UEFI_DRIVER
+  // not to degrade 64-bit MMIO BARs for the device, even if a PCI option ROM
+  // BAR is present on the device.
+  //
+
+  //
+  // This member function is mis-specified actually: it is supposed to allocate
+  // memory, but as specified, it could not return an error status. Thankfully,
+  // the edk2 PCI Bus UEFI_DRIVER actually handles error codes; see the
+  // UpdatePciInfo() function.
+  //
+  *Configuration = AllocateCopyPool (sizeof mConfiguration, &mConfiguration);
+  if (*Configuration == NULL) {
+    DEBUG ((EFI_D_WARN,
+      "%a: 64-bit MMIO BARs may be degraded for PCI 0x%04x:0x%04x (rev %d)\n",
+      __FUNCTION__, (UINT32)VendorId, (UINT32)DeviceId, (UINT8)RevisionId));
+    return EFI_OUT_OF_RESOURCES;
+  }
+  return EFI_SUCCESS;
+}
+
+
+/**
+  Entry point for this driver.
+
+  @param[in] ImageHandle  Image handle of this driver.
+  @param[in] SystemTable  Pointer to SystemTable.
+
+  @retval EFI_SUCESS       Driver has loaded successfully.
+  @retval EFI_UNSUPPORTED  PCI resource allocation has been disabled.
+  @retval EFI_UNSUPPORTED  There is no 64-bit PCI MMIO aperture.
+  @return                  Error codes from lower level functions.
+
+**/
+EFI_STATUS
+EFIAPI
+DriverInitialize (
+  IN EFI_HANDLE       ImageHandle,
+  IN EFI_SYSTEM_TABLE *SystemTable
+  )
+{
+  //
+  // If the PCI Bus driver is not supposed to allocate resources, then it makes
+  // no sense to install a protocol that influences the resource allocation.
+  //
+  // Similarly, if there is no 64-bit PCI MMIO aperture, then 64-bit MMIO BARs
+  // have to be allocated under 4 GB unconditionally.
+  //
+  if (PcdGetBool (PcdPciDisableBusEnumeration) ||
+      PcdGet64 (PcdPciMmio64Size) == 0) {
+    return EFI_UNSUPPORTED;
+  }
+
+  mIncompatiblePciDeviceSupport.CheckDevice = CheckDevice;
+  return gBS->InstallMultipleProtocolInterfaces (&ImageHandle,
+                &gEfiIncompatiblePciDeviceSupportProtocolGuid,
+                &mIncompatiblePciDeviceSupport, NULL);
+}
diff --git a/ArmPkg/Drivers/IncompatiblePciDeviceSupportDxe/IncompatiblePciDeviceSupport.inf b/ArmPkg/Drivers/IncompatiblePciDeviceSupportDxe/IncompatiblePciDeviceSupport.inf
new file mode 100644
index 000000000000..0bda20199d51
--- /dev/null
+++ b/ArmPkg/Drivers/IncompatiblePciDeviceSupportDxe/IncompatiblePciDeviceSupport.inf
@@ -0,0 +1,49 @@
+## @file
+# A simple DXE_DRIVER that causes the PCI Bus UEFI_DRIVER to allocate 64-bit
+# MMIO BARs above 4 GB, regardless of option ROM availability, conserving
+# 32-bit MMIO aperture for 32-bit BARs.
+#
+# Copyright (C) 2016, Red Hat, Inc.
+# Copyright (C) 2016, Linaro, Ltd.
+#
+# This program and the accompanying materials are licensed and made available
+# under the terms and conditions of the BSD License which accompanies this
+# distribution. The full text of the license may be found at
+# http://opensource.org/licenses/bsd-license.php
+#
+# THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS, WITHOUT
+# WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
+##
+
+[Defines]
+  INF_VERSION                    = 0x00010005
+  BASE_NAME                      = IncompatiblePciDeviceSupportDxe
+  FILE_GUID                      = 18BCB238-844E-446B-AA2D-3DF38A25FA0F
+  MODULE_TYPE                    = DXE_DRIVER
+  VERSION_STRING                 = 1.0
+  ENTRY_POINT                    = DriverInitialize
+
+[Sources]
+  IncompatiblePciDeviceSupport.c
+
+[Packages]
+  ArmPkg/ArmPkg.dec
+  MdeModulePkg/MdeModulePkg.dec
+  MdePkg/MdePkg.dec
+
+[LibraryClasses]
+  DebugLib
+  MemoryAllocationLib
+  PcdLib
+  UefiBootServicesTableLib
+  UefiDriverEntryPoint
+
+[Protocols]
+  gEfiIncompatiblePciDeviceSupportProtocolGuid               ## PRODUCES
+
+[Pcd]
+  gArmTokenSpaceGuid.PcdPciMmio64Size                        ## CONSUMES
+  gEfiMdeModulePkgTokenSpaceGuid.PcdPciDisableBusEnumeration ## CONSUMES
+
+[Depex]
+  TRUE
-- 
2.7.4