KvmtoolRtcFdtClientLib.c

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#include <Library/BaseLib.h>
#include <Library/DebugLib.h>
#include <Library/DxeServicesTableLib.h>
#include <Library/PcdLib.h>
#include <Library/UefiBootServicesTableLib.h>
#include <Protocol/FdtClient.h>
 
#define RTC_INDEX_REG_OFFSET  0x0ULL
 
#define RTC_TARGET_REG_OFFSET  0x1ULL
 
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 | EFI_MEMORY_XP
                  );
  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 | EFI_MEMORY_XP
                  );
  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;
}
 
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",
      __func__
      ));
    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",
      __func__
      ));
    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;
}