ArmVirtPkg/Library/ArmVirtPL031FdtClientLib/ArmVirtPL031FdtClientLib.c

   1 /** @file
   2   FDT client library for ARM's PL031 RTC driver
   3
   4   Copyright (c) 2016, Linaro Ltd. All rights reserved.<BR>
   5
   6   This program and the accompanying materials
   7   are licensed and made available under the terms and conditions of the BSD License
   8   which accompanies this distribution.  The full text of the license may be found at
   9   http://opensource.org/licenses/bsd-license.php
  10
  11   THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
  12   WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
  13
  14 **/
  15
  16 #include <Uefi.h>
  17
  18 #include <Library/BaseLib.h>
  19 #include <Library/DebugLib.h>
  20 #include <Library/PcdLib.h>
  21 #include <Library/UefiBootServicesTableLib.h>
  22
  23 #include <Protocol/FdtClient.h>
  24
  25 RETURN_STATUS
  26 EFIAPI
  27 ArmVirtPL031FdtClientLibConstructor (
  28   VOID
  29   )
  30 {
  31   EFI_STATUS                    Status;
  32   FDT_CLIENT_PROTOCOL           *FdtClient;
  33   INT32                         Node;
  34   CONST UINT64                  *Reg;
  35   UINT32                        RegSize;
  36   UINT64                        RegBase;
  37   RETURN_STATUS                 PcdStatus;
  38
  39   Status = gBS->LocateProtocol (&gFdtClientProtocolGuid, NULL,
  40                   (VOID **)&FdtClient);
  41   ASSERT_EFI_ERROR (Status);
  42
  43   Status = FdtClient->FindCompatibleNode (FdtClient, "arm,pl031", &Node);
  44   if (EFI_ERROR (Status)) {
  45     DEBUG ((EFI_D_WARN, "%a: No 'arm,pl031' compatible DT node found\n",
  46       __FUNCTION__));
  47     return EFI_SUCCESS;
  48   }
  49
  50   Status = FdtClient->GetNodeProperty (FdtClient, Node, "reg",
  51                         (CONST VOID **)&Reg, &RegSize);
  52   if (EFI_ERROR (Status)) {
  53     DEBUG ((EFI_D_WARN,
  54       "%a: No 'reg' property found in 'arm,pl031' compatible DT node\n",
  55       __FUNCTION__));
  56     return EFI_SUCCESS;
  57   }
  58
  59   ASSERT (RegSize == 16);
  60
  61   RegBase = SwapBytes64 (Reg[0]);
  62   ASSERT (RegBase < MAX_UINT32);
  63
  64   PcdStatus = PcdSet32S (PcdPL031RtcBase, (UINT32)RegBase);
  65   ASSERT_RETURN_ERROR (PcdStatus);
  66
  67   DEBUG ((EFI_D_INFO, "Found PL031 RTC @ 0x%Lx\n", RegBase));
  68
  69   if (!FeaturePcdGet (PcdPureAcpiBoot)) {
  70     //
  71     // UEFI takes ownership of the RTC hardware, and exposes its functionality
  72     // through the UEFI Runtime Services GetTime, SetTime, etc. This means we
  73     // need to disable it in the device tree to prevent the OS from attaching
  74     // its device driver as well.
  75     //
  76     Status = FdtClient->SetNodeProperty (FdtClient, Node, "status",
  77                           "disabled", sizeof ("disabled"));
  78     if (EFI_ERROR (Status)) {
  79         DEBUG ((EFI_D_WARN, "Failed to set PL031 status to 'disabled'\n"));
  80     }
  81   }
  82
  83   return EFI_SUCCESS;
  84 }