[PATCH edk2-platforms v1 04/12] Platform/ARM/VExpressPkg: Configure SMMUv3 for FVP RevC

["Sami Mujawar" <sami.mujawar@arm.com>]

Base Platform RevC is a configuration of the Base Platform
that includes a SMMUv3. TF-A configures the SMMUv3 to 'Abort
all incoming transactions in order to implement a default
deny policy on reset'. This prevents the firmware from using
the AHCI-SATA disk that is available as a PCIe device.

According to Server Base System Architecture (SBSA) 6.1,
Section A Level 3 - firmware, Sub-section A.1 Memory map,
'All Non-secure on-chip masters in a base server system
that are expected to be used by the platform firmware must
be capable of addressing all of the Non-secure address
space. If the master goes through a SMMU then the master
must be capable of addressing all of the Non-secure address
space even when the SMMU is off.'

Therefore, configure the SMMUv3 to set Non-secure streams
to bypass the SMMU. On firmware hand-off the OS is expected
to reconfigure the SMMU.

Signed-off-by: Sami Mujawar <sami.mujawar@arm.com>
---
 Platform/ARM/VExpressPkg/Drivers/ArmVExpressDxe/ArmFvpDxe.c   | 110 +++++++++++++++++++-
 Platform/ARM/VExpressPkg/Drivers/ArmVExpressDxe/ArmFvpDxe.inf |   4 +-
 2 files changed, 112 insertions(+), 2 deletions(-)

diff --git a/Platform/ARM/VExpressPkg/Drivers/ArmVExpressDxe/ArmFvpDxe.c b/Platform/ARM/VExpressPkg/Drivers/ArmVExpressDxe/ArmFvpDxe.c
index 189069484b57533ce43bcdccb30c85c882fc7ffb..1f1dfd3de5b9aedc1515d55a15963df75a295326 100644
--- a/Platform/ARM/VExpressPkg/Drivers/ArmVExpressDxe/ArmFvpDxe.c
+++ b/Platform/ARM/VExpressPkg/Drivers/ArmVExpressDxe/ArmFvpDxe.c
@@ -1,6 +1,6 @@
 /** @file
 
-  Copyright (c) 2013-2015, ARM Ltd. All rights reserved.<BR>
+  Copyright (c) 2013-2021, Arm Ltd. All rights reserved.<BR>
 
   SPDX-License-Identifier: BSD-2-Clause-Patent
 
@@ -11,6 +11,8 @@
 #include <Library/ArmShellCmdLib.h>
 #include <Library/BaseMemoryLib.h>
 #include <Library/DebugLib.h>
+#include <Library/IoLib.h>
+#include <Library/TimerLib.h>
 #include <Library/UefiBootServicesTableLib.h>
 #include <Library/VirtioMmioDeviceLib.h>
 
@@ -18,6 +20,13 @@
 
 #define ARM_FVP_BASE_VIRTIO_BLOCK_BASE    0x1c130000
 
+// SMMUv3 Global Bypass Attribute (GBPA) register offset.
+#define SMMU_GBPA                         0x0044
+
+// SMMU_GBPA register fields.
+#define SMMU_GBPA_UPDATE                  BIT31
+#define SMMU_GBPA_ABORT                   BIT20
+
 #pragma pack(1)
 typedef struct {
   VENDOR_DEVICE_PATH                  Vendor;
@@ -49,6 +58,92 @@ VIRTIO_BLK_DEVICE_PATH mVirtioBlockDevicePath =
 };
 
 /**
+  Poll the SMMU register and test the value based on the mask.
+
+  @param [in]  SmmuReg    Base address of the SMMU register.
+  @param [in]  Mask       Mask of register bits to monitor.
+  @param [in]  Value      Expected value.
+
+  @retval EFI_SUCCESS     Success.
+  @retval EFI_TIMEOUT     Timeout.
+**/
+STATIC
+EFI_STATUS
+EFIAPI
+SmmuV3Poll (
+  IN  UINT64 SmmuReg,
+  IN  UINT32 Mask,
+  IN  UINT32 Value
+  )
+{
+  UINT32 RegVal;
+  UINTN  Count;
+
+  // Set 1ms timeout value.
+  Count = 10;
+  do {
+    RegVal = MmioRead32 (SmmuReg);
+    if ((RegVal & Mask) == Value) {
+      return EFI_SUCCESS;
+    }
+    MicroSecondDelay (100);
+  } while ((--Count) > 0);
+
+  DEBUG ((DEBUG_ERROR, "Timeout polling SMMUv3 register @%p\n", SmmuReg));
+  DEBUG ((
+    DEBUG_ERROR,
+    "Read value 0x%x, expected 0x%x\n",
+    RegVal,
+    ((Value == 0) ? (RegVal & ~Mask) : (RegVal | Mask))
+    ));
+  return EFI_TIMEOUT;
+}
+
+/**
+  Initialise the SMMUv3 to set Non-secure streams to bypass the SMMU.
+
+  @param [in]  SmmuReg    Base address of the SMMUv3.
+
+  @retval EFI_SUCCESS     Success.
+  @retval EFI_TIMEOUT     Timeout.
+**/
+STATIC
+EFI_STATUS
+EFIAPI
+SmmuV3Init (
+  IN  UINT64 SmmuBase
+  )
+{
+  EFI_STATUS  Status;
+  UINT32      RegVal;
+
+  // Attribute update has completed when SMMU_(S)_GBPA.Update bit is 0.
+  Status = SmmuV3Poll (SmmuBase + SMMU_GBPA, SMMU_GBPA_UPDATE, 0);
+  if (EFI_ERROR (Status)) {
+    return Status;
+  }
+
+  // SMMU_(S)_CR0 resets to zero with all streams bypassing the SMMU,
+  // so just abort all incoming transactions.
+  RegVal = MmioRead32 (SmmuBase + SMMU_GBPA);
+
+  // TF-A configures the SMMUv3 to abort all incoming transactions.
+  // Clear the SMMU_GBPA.ABORT to allow Non-secure streams to bypass
+  // the SMMU.
+  RegVal &= ~SMMU_GBPA_ABORT;
+  RegVal |= SMMU_GBPA_UPDATE;
+
+  MmioWrite32 (SmmuBase + SMMU_GBPA, RegVal);
+
+  Status = SmmuV3Poll (SmmuBase + SMMU_GBPA, SMMU_GBPA_UPDATE, 0);
+  if (EFI_ERROR (Status)) {
+    return Status;
+  }
+
+  return EFI_SUCCESS;
+}
+
+/**
  * Generic UEFI Entrypoint for 'ArmFvpDxe' driver
  * See UEFI specification for the details of the parameters
  */
@@ -60,6 +155,7 @@ ArmFvpInitialise (
   )
 {
   EFI_STATUS                   Status;
+  UINT32                       SysId;
 
   Status = gBS->InstallProtocolInterface (&ImageHandle,
                  &gEfiDevicePathProtocolGuid, EFI_NATIVE_INTERFACE,
@@ -80,5 +176,17 @@ ArmFvpInitialise (
     DEBUG ((EFI_D_ERROR, "ArmFvpDxe: Failed to install ShellDynCmdRunAxf\n"));
   }
 
+  // If FVP RevC - Configure SMMUv3 to set NS transactions in bypass mode.
+  SysId = MmioRead32 (ARM_VE_SYS_ID_REG);
+  if ((SysId & ARM_FVP_SYS_ID_REV_MASK) == ARM_FVP_BASE_REVC_REV) {
+    Status = SmmuV3Init (FVP_REVC_SMMUV3_BASE);
+    if (EFI_ERROR (Status)) {
+      DEBUG ((
+        DEBUG_ERROR,
+        "ArmFvpDxe: Failed to initialise SMMUv3 in bypass mode.\n"
+        ));
+    }
+  }
+
   return Status;
 }
diff --git a/Platform/ARM/VExpressPkg/Drivers/ArmVExpressDxe/ArmFvpDxe.inf b/Platform/ARM/VExpressPkg/Drivers/ArmVExpressDxe/ArmFvpDxe.inf
index a4021c2d9e241845736eea428a479a4abddd6413..c5f41795310141ae9d7c175c26d5694590a0a08a 100644
--- a/Platform/ARM/VExpressPkg/Drivers/ArmVExpressDxe/ArmFvpDxe.inf
+++ b/Platform/ARM/VExpressPkg/Drivers/ArmVExpressDxe/ArmFvpDxe.inf
@@ -1,6 +1,6 @@
 #/** @file
 #
-#  Copyright (c) 2013-2015, ARM Ltd. All rights reserved.<BR>
+#  Copyright (c) 2013-2021, Arm Ltd. All rights reserved.<BR>
 #
 #  SPDX-License-Identifier: BSD-2-Clause-Patent
 #
@@ -28,6 +28,8 @@ [Packages]
 [LibraryClasses]
   ArmShellCmdRunAxfLib
   BaseMemoryLib
+  IoLib
+  TimerLib
   UefiDriverEntryPoint
   UefiBootServicesTableLib
   VirtioMmioDeviceLib
-- 
'Guid(CE165669-3EF3-493F-B85D-6190EE5B9759)'