[PATCH v4 02/15] ArmVirtPkg: Add Kvmtool RTC Fdt Client Library

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

Add library that parses the Kvmtool device tree and updates
the dynamic PCDs describing the RTC Memory map.

It also maps the MMIO region used by the RTC as runtime memory
so that the RTC registers are accessible post ExitBootServices.

Since UEFI takes ownership of the RTC hardware disable the RTC
node in the DT to prevent the OS from attaching its device
driver as well.

Signed-off-by: Sami Mujawar <sami.mujawar@arm.com>
---

Notes:
    v4:
      - Updated based on review comments.                             [Sami]
      - Cleanup include file list, make local functions static,       [Ard]
        drop EFIAPI, use EFI_PAGE_MASK and use ReadUnaligned64.
        Ref: https://edk2.groups.io/g/devel/topic/75081472
    
    v3:
      - Introduce library to read and map the MMIO base addresses     [Sami]
        for the RTC registers from the DT and configure the Index
        and Target register PCDs.

 ArmVirtPkg/Library/KvmtoolRtcFdtClientLib/KvmtoolRtcFdtClientLib.c   | 230 ++++++++++++++++++++
 ArmVirtPkg/Library/KvmtoolRtcFdtClientLib/KvmtoolRtcFdtClientLib.inf |  42 ++++
 2 files changed, 272 insertions(+)

diff --git a/ArmVirtPkg/Library/KvmtoolRtcFdtClientLib/KvmtoolRtcFdtClientLib.c b/ArmVirtPkg/Library/KvmtoolRtcFdtClientLib/KvmtoolRtcFdtClientLib.c
new file mode 100644
index 0000000000000000000000000000000000000000..93715958952f933007ff143a22cbe81606cc539e
--- /dev/null
+++ b/ArmVirtPkg/Library/KvmtoolRtcFdtClientLib/KvmtoolRtcFdtClientLib.c
@@ -0,0 +1,230 @@
+/** @file
+  FDT client library for motorola,mc146818 RTC driver
+
+  Copyright (c) 2020, ARM Limited. All rights reserved.<BR>
+
+  SPDX-License-Identifier: BSD-2-Clause-Patent
+
+**/
+
+#include <Library/BaseLib.h>
+#include <Library/DebugLib.h>
+#include <Library/DxeServicesTableLib.h>
+#include <Library/PcdLib.h>
+#include <Library/UefiBootServicesTableLib.h>
+#include <Protocol/FdtClient.h>
+
+/** RTC Index register is at offset 0x0
+*/
+#define RTC_INDEX_REG_OFFSET    0x0ULL
+
+/** RTC Target register is at offset 0x1
+*/
+#define RTC_TARGET_REG_OFFSET   0x1ULL
+
+/** Add the RTC controller address range to the memory map.
+
+  @param [in]  ImageHandle  The handle to the image.
+  @param [in]  RtcPageBase  Base address of the RTC controller.
+
+  @retval EFI_SUCCESS             Success.
+  @retval EFI_INVALID_PARAMETER   A parameter is invalid.
+  @retval EFI_NOT_FOUND           Flash device not found.
+**/
+STATIC
+EFI_STATUS
+KvmtoolRtcMapMemory (
+  IN EFI_HANDLE               ImageHandle,
+  IN EFI_PHYSICAL_ADDRESS     RtcPageBase
+  )
+{
+  EFI_STATUS  Status;
+
+  Status = gDS->AddMemorySpace (
+                  EfiGcdMemoryTypeMemoryMappedIo,
+                  RtcPageBase,
+                  EFI_PAGE_SIZE,
+                  EFI_MEMORY_UC | EFI_MEMORY_RUNTIME
+                  );
+  if (EFI_ERROR (Status)) {
+    DEBUG ((
+      DEBUG_ERROR, "Failed to add memory space. Status = %r\n",
+      Status
+      ));
+    return Status;
+  }
+
+  Status = gDS->AllocateMemorySpace (
+                  EfiGcdAllocateAddress,
+                  EfiGcdMemoryTypeMemoryMappedIo,
+                  0,
+                  EFI_PAGE_SIZE,
+                  &RtcPageBase,
+                  ImageHandle,
+                  NULL
+                  );
+  if (EFI_ERROR (Status)) {
+    DEBUG ((
+      DEBUG_ERROR,
+      "Failed to allocate memory space. Status = %r\n",
+      Status
+      ));
+    gDS->RemoveMemorySpace (
+           RtcPageBase,
+           EFI_PAGE_SIZE
+           );
+    return Status;
+  }
+
+  Status = gDS->SetMemorySpaceAttributes (
+                  RtcPageBase,
+                  EFI_PAGE_SIZE,
+                  EFI_MEMORY_UC | EFI_MEMORY_RUNTIME
+                  );
+  if (EFI_ERROR (Status)) {
+    DEBUG ((
+      DEBUG_ERROR,
+      "Failed to set memory attributes. Status = %r\n",
+      Status
+      ));
+    gDS->FreeMemorySpace (
+           RtcPageBase,
+           EFI_PAGE_SIZE
+           );
+    gDS->RemoveMemorySpace (
+           RtcPageBase,
+           EFI_PAGE_SIZE
+           );
+  }
+
+  return Status;
+}
+
+/** Entrypoint for KvmtoolRtcFdtClientLib.
+
+  Locate the RTC node in the DT and update the Index and
+  Target register base addresses in the respective PCDs.
+  Add the RTC memory region to the memory map.
+  Disable the RTC node as the RTC is owned by UEFI.
+
+  @param [in]  ImageHandle  The handle to the image.
+  @param [in]  SystemTable  Pointer to the System Table.
+
+  @retval EFI_SUCCESS             Success.
+  @retval EFI_INVALID_PARAMETER   A parameter is invalid.
+  @retval EFI_NOT_FOUND           Flash device not found.
+**/
+EFI_STATUS
+EFIAPI
+KvmtoolRtcFdtClientLibConstructor (
+  IN EFI_HANDLE         ImageHandle,
+  IN EFI_SYSTEM_TABLE   *SystemTable
+  )
+{
+  EFI_STATUS            Status;
+  FDT_CLIENT_PROTOCOL   *FdtClient;
+  INT32                 Node;
+  CONST UINT32          *Reg;
+  UINT32                RegSize;
+  UINT64                RegBase;
+  UINT64                Range;
+  RETURN_STATUS         PcdStatus;
+
+  Status = gBS->LocateProtocol (
+                  &gFdtClientProtocolGuid,
+                  NULL,
+                  (VOID **)&FdtClient
+                  );
+  ASSERT_EFI_ERROR (Status);
+
+  Status = FdtClient->FindCompatibleNode (
+                        FdtClient,
+                        "motorola,mc146818",
+                        &Node
+                        );
+  if (EFI_ERROR (Status)) {
+    DEBUG ((
+      DEBUG_ERROR,
+      "%a: No 'motorola,mc146818' compatible DT node found\n",
+      __FUNCTION__
+      ));
+    return Status;
+  }
+
+  Status = FdtClient->GetNodeProperty (
+                        FdtClient,
+                        Node,
+                        "reg",
+                        (CONST VOID **)&Reg,
+                        &RegSize
+                        );
+  if (EFI_ERROR (Status)) {
+    DEBUG ((
+      DEBUG_ERROR,
+      "%a: No 'reg' property found in 'motorola,mc146818' compatible DT node\n",
+      __FUNCTION__
+      ));
+    return Status;
+  }
+
+  ASSERT (RegSize == 16);
+
+  RegBase = SwapBytes64 (ReadUnaligned64 ((VOID *)&Reg[0]));
+  Range = SwapBytes64 (ReadUnaligned64 ((VOID *)&Reg[2]));
+  DEBUG ((
+    DEBUG_INFO,
+    "Found motorola,mc146818 RTC @ 0x%Lx Range = 0x%x\n",
+    RegBase,
+    Range
+    ));
+
+  // The address range must cover the RTC Index and the Target registers.
+  ASSERT (Range >= 0x2);
+
+  // RTC Index register is at offset 0x0
+  PcdStatus = PcdSet64S (
+                PcdRtcIndexRegister64,
+                (RegBase + RTC_INDEX_REG_OFFSET)
+                );
+  ASSERT_RETURN_ERROR (PcdStatus);
+
+  // RTC Target register is at offset 0x1
+  PcdStatus = PcdSet64S (
+                PcdRtcTargetRegister64,
+                (RegBase + RTC_TARGET_REG_OFFSET)
+                );
+  ASSERT_RETURN_ERROR (PcdStatus);
+
+  Status = KvmtoolRtcMapMemory (ImageHandle, (RegBase & ~EFI_PAGE_MASK));
+  if (EFI_ERROR (Status)) {
+    DEBUG ((
+      DEBUG_ERROR,
+      "Failed to map memory for motorola,mc146818. Status = %r\n",
+      Status
+      ));
+    return Status;
+  }
+
+  //
+  // UEFI takes ownership of the RTC hardware, and exposes its functionality
+  // through the UEFI Runtime Services GetTime, SetTime, etc. This means we
+  // need to disable it in the device tree to prevent the OS from attaching
+  // its device driver as well.
+  //
+  Status = FdtClient->SetNodeProperty (
+                        FdtClient,
+                        Node,
+                        "status",
+                        "disabled",
+                        sizeof ("disabled")
+                        );
+  if (EFI_ERROR (Status)) {
+    DEBUG ((
+      DEBUG_WARN,
+      "Failed to set motorola,mc146818 status to 'disabled', Status = %r\n",
+      Status
+      ));
+  }
+
+  return EFI_SUCCESS;
+}
diff --git a/ArmVirtPkg/Library/KvmtoolRtcFdtClientLib/KvmtoolRtcFdtClientLib.inf b/ArmVirtPkg/Library/KvmtoolRtcFdtClientLib/KvmtoolRtcFdtClientLib.inf
new file mode 100644
index 0000000000000000000000000000000000000000..0d1b27997ed00d7c1be3578cab4d1d2eba663a90
--- /dev/null
+++ b/ArmVirtPkg/Library/KvmtoolRtcFdtClientLib/KvmtoolRtcFdtClientLib.inf
@@ -0,0 +1,42 @@
+#/** @file
+#  FDT client library for motorola,mc146818 RTC driver
+#
+#  Copyright (c) 2020, ARM Limited. All rights reserved.<BR>
+#
+#  SPDX-License-Identifier: BSD-2-Clause-Patent
+#
+#**/
+
+[Defines]
+  INF_VERSION                    = 0x0001001B
+  BASE_NAME                      = KvmtoolRtcFdtClientLib
+  FILE_GUID                      = 3254B4F7-30B5-48C6-B06A-D8FF97F3EF95
+  MODULE_TYPE                    = DXE_DRIVER
+  VERSION_STRING                 = 1.0
+  LIBRARY_CLASS                  = KvmtoolRtcFdtClientLib|DXE_DRIVER DXE_RUNTIME_DRIVER
+  CONSTRUCTOR                    = KvmtoolRtcFdtClientLibConstructor
+
+[Sources]
+  KvmtoolRtcFdtClientLib.c
+
+[Packages]
+  ArmVirtPkg/ArmVirtPkg.dec
+  MdePkg/MdePkg.dec
+  PcAtChipsetPkg/PcAtChipsetPkg.dec
+
+[LibraryClasses]
+  BaseLib
+  DebugLib
+  PcdLib
+  UefiBootServicesTableLib
+  DxeServicesTableLib
+
+[Protocols]
+  gFdtClientProtocolGuid                                ## CONSUMES
+
+[Pcd]
+  gPcAtChipsetPkgTokenSpaceGuid.PcdRtcIndexRegister64
+  gPcAtChipsetPkgTokenSpaceGuid.PcdRtcTargetRegister64
+
+[Depex]
+  gFdtClientProtocolGuid
-- 
'Guid(CE165669-3EF3-493F-B85D-6190EE5B9759)'