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/******************************Module*Header*******************************\
* Module Name: bdd_util.cxx
*
* Basic Display Driver utility functions
*
* Created: 29-Mar-2011
* Author: Amos Eshel [amosesh]
*
* Copyright (c) 2011 Microsoft Corporation
\**************************************************************************/
#include "BDD.hxx"
#pragma code_seg("PAGE")
//
// EDID validation
//
BOOLEAN IsEdidHeaderValid(_In_reads_bytes_(EDID_V1_BLOCK_SIZE) const BYTE* pEdid)
{
PAGED_CODE();
static const UCHAR EDID1Header[8] = {0,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0};
return memcmp(pEdid, EDID1Header, sizeof(EDID1Header)) == 0;
}
BOOLEAN IsEdidChecksumValid(_In_reads_bytes_(EDID_V1_BLOCK_SIZE) const BYTE* pEdid)
{
PAGED_CODE();
BYTE CheckSum = 0;
for (const BYTE* pEdidStart = pEdid; pEdidStart < (pEdid + EDID_V1_BLOCK_SIZE); ++pEdidStart)
{
CheckSum += *pEdidStart;
}
return CheckSum == 0;
}
//
// Frame buffer map/unmap
//
NTSTATUS
MapFrameBuffer(
_In_ PHYSICAL_ADDRESS PhysicalAddress,
_In_ ULONG Length,
_Outptr_result_bytebuffer_(Length) VOID** VirtualAddress)
{
PAGED_CODE();
//
// Check for parameters
//
if ((PhysicalAddress.QuadPart == (ULONGLONG)0) ||
(Length == 0) ||
(VirtualAddress == NULL))
{
BDD_LOG_ERROR3("One of PhysicalAddress.QuadPart (0x%I64x), Length (0x%I64x), VirtualAddress (0x%I64x) is NULL or 0",
PhysicalAddress.QuadPart, Length, VirtualAddress);
return STATUS_INVALID_PARAMETER;
}
*VirtualAddress = MmMapIoSpaceEx(PhysicalAddress,
Length,
PAGE_READWRITE | PAGE_WRITECOMBINE);
if (*VirtualAddress == NULL)
{
// The underlying call to MmMapIoSpace failed. This may be because, MmWriteCombined
// isn't supported, so try again with MmNonCached
*VirtualAddress = MmMapIoSpaceEx(PhysicalAddress,
Length,
PAGE_READWRITE | PAGE_NOCACHE);
if (*VirtualAddress == NULL)
{
BDD_LOG_LOW_RESOURCE1("MmMapIoSpace returned a NULL buffer when trying to allocate 0x%I64x bytes", Length);
return STATUS_NO_MEMORY;
}
}
return STATUS_SUCCESS;
}
NTSTATUS
UnmapFrameBuffer(
_In_reads_bytes_(Length) VOID* VirtualAddress,
_In_ ULONG Length)
{
PAGED_CODE();
//
// Check for parameters
//
if ((VirtualAddress == NULL) && (Length == 0))
{
// Allow this function to be called when there's no work to do, and treat as successful
return STATUS_SUCCESS;
}
else if ((VirtualAddress == NULL) || (Length == 0))
{
BDD_LOG_ERROR2("Only one of Length (0x%I64x), VirtualAddress (0x%I64x) is NULL or 0",
Length, VirtualAddress);
return STATUS_INVALID_PARAMETER;
}
MmUnmapIoSpace(VirtualAddress,
Length);
return STATUS_SUCCESS;
}
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