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/*++
Copyright (c) 2013-2014, ARM Ltd. All rights reserved.<BR>
SPDX-License-Identifier: BSD-2-Clause-Patent
Module Name:
ArmGicDxe.c
Abstract:
Driver implementing the GIC interrupt controller protocol
--*/
#include <PiDxe.h>
#include "ArmGicDxe.h"
STATIC
BOOLEAN
GicV3Supported (
VOID
)
{
UINT32 IccSre;
// Ideally we would like to use the GICC IIDR Architecture version here, but
// this does not seem to be very reliable as the implementation could easily
// get it wrong. It is more reliable to check if the GICv3 System Register
// feature is implemented on the CPU. This is also convenient as our GICv3
// driver requires SRE. If only Memory mapped access is available we try to
// drive the GIC as a v2.
if (ArmHasGicSystemRegisters ()) {
// Make sure System Register access is enabled (SRE). This depends on the
// higher privilege level giving us permission, otherwise we will either
// cause an exception here, or the write doesn't stick in which case we need
// to fall back to the GICv2 MMIO interface.
// Note: We do not need to set ICC_SRE_EL2.Enable because the OS is started
// at the same exception level.
// It is the OS responsibility to set this bit.
IccSre = ArmGicV3GetControlSystemRegisterEnable ();
if (!(IccSre & ICC_SRE_EL2_SRE)) {
ArmGicV3SetControlSystemRegisterEnable (IccSre | ICC_SRE_EL2_SRE);
IccSre = ArmGicV3GetControlSystemRegisterEnable ();
}
if (IccSre & ICC_SRE_EL2_SRE) {
return TRUE;
}
}
return FALSE;
}
/**
Initialize the state information for the CPU Architectural Protocol
@param ImageHandle of the loaded driver
@param SystemTable Pointer to the System Table
@retval EFI_SUCCESS Protocol registered
@retval EFI_OUT_OF_RESOURCES Cannot allocate protocol data structure
@retval EFI_DEVICE_ERROR Hardware problems
@retval EFI_UNSUPPORTED GIC version not supported
**/
EFI_STATUS
InterruptDxeInitialize (
IN EFI_HANDLE ImageHandle,
IN EFI_SYSTEM_TABLE *SystemTable
)
{
EFI_STATUS Status;
if (!GicV3Supported ()) {
Status = GicV2DxeInitialize (ImageHandle, SystemTable);
} else {
Status = GicV3DxeInitialize (ImageHandle, SystemTable);
}
return Status;
}
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