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/** @file
FDT client library for ARM's PL031 RTC driver
Copyright (c) 2016, Linaro Ltd. All rights reserved.<BR>
SPDX-License-Identifier: BSD-2-Clause-Patent
**/
#include <Uefi.h>
#include <Library/BaseLib.h>
#include <Library/DebugLib.h>
#include <Library/PcdLib.h>
#include <Library/UefiBootServicesTableLib.h>
#include <Protocol/FdtClient.h>
RETURN_STATUS
EFIAPI
ArmVirtPL031FdtClientLibConstructor (
VOID
)
{
EFI_STATUS Status;
FDT_CLIENT_PROTOCOL *FdtClient;
INT32 Node;
CONST UINT64 *Reg;
UINT32 RegSize;
UINT64 RegBase;
RETURN_STATUS PcdStatus;
Status = gBS->LocateProtocol (
&gFdtClientProtocolGuid,
NULL,
(VOID **)&FdtClient
);
ASSERT_EFI_ERROR (Status);
Status = FdtClient->FindCompatibleNode (FdtClient, "arm,pl031", &Node);
if (EFI_ERROR (Status)) {
DEBUG ((
DEBUG_WARN,
"%a: No 'arm,pl031' compatible DT node found\n",
__func__
));
return EFI_SUCCESS;
}
Status = FdtClient->GetNodeProperty (
FdtClient,
Node,
"reg",
(CONST VOID **)&Reg,
&RegSize
);
if (EFI_ERROR (Status)) {
DEBUG ((
DEBUG_WARN,
"%a: No 'reg' property found in 'arm,pl031' compatible DT node\n",
__func__
));
return EFI_SUCCESS;
}
ASSERT (RegSize == 16);
RegBase = SwapBytes64 (Reg[0]);
ASSERT (RegBase < MAX_UINT32);
PcdStatus = PcdSet32S (PcdPL031RtcBase, (UINT32)RegBase);
ASSERT_RETURN_ERROR (PcdStatus);
DEBUG ((DEBUG_INFO, "Found PL031 RTC @ 0x%Lx\n", RegBase));
//
// 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 PL031 status to 'disabled'\n"));
}
return EFI_SUCCESS;
}
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