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ArmPlatformPkg/NorFlashDxe: Optimise FVB protocol

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- Only read what needs reading, don't read the whole block.
- Don't write back buffers containing no data after an erase.
- Reduce number of NOR erases when writing data. Only erase the block
  when required.

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Harry Liebel <Harry.Liebel@arm.com>
Reviewed-by: Olivier Martin <olivier.martin@arm.com>



git-svn-id: https://svn.code.sf.net/p/edk2/code/trunk/edk2@15500 6f19259b-4bc3-4df7-8a09-765794883524
This commit is contained in:
Harry Liebel
2014-05-08 14:48:55 +00:00
committed by oliviermartin
parent 0fb7e718a8
commit 518c243d42
3 changed files with 237 additions and 30 deletions
Download Patch File Download Diff File Expand all files Collapse all files

178
ArmPlatformPkg/Drivers/NorFlashDxe/NorFlashFvbDxe.c
View File

@@ -417,7 +417,6 @@ FvbRead (
IN OUT UINT8 *Buffer
)
{
EFI_STATUS Status;
EFI_STATUS TempStatus;
UINTN BlockSize;
NOR_FLASH_INSTANCE *Instance;
@@ -430,8 +429,7 @@ FvbRead (
Instance->Initialize(Instance);
}
Status = EFI_SUCCESS;
TempStatus = Status;
TempStatus = EFI_SUCCESS;
// Cache the block size to avoid de-referencing pointers all the time
BlockSize = Instance->Media.BlockSize;
@@ -452,25 +450,21 @@ FvbRead (
return EFI_BAD_BUFFER_SIZE;
}
// Check we did get some memory
if (Instance->FvbBuffer == NULL) {
DEBUG ((EFI_D_ERROR, "FvbRead: ERROR - Buffer not ready\n"));
return EFI_DEVICE_ERROR;
// Decide if we are doing full block reads or not.
if (*NumBytes % BlockSize != 0) {
TempStatus = NorFlashRead (Instance, Instance->StartLba + Lba, Offset, *NumBytes, Buffer);
if (EFI_ERROR (TempStatus)) {
return EFI_DEVICE_ERROR;
}
} else {
// Read NOR Flash data into shadow buffer
TempStatus = NorFlashReadBlocks (Instance, Instance->StartLba + Lba, BlockSize, Buffer);
if (EFI_ERROR (TempStatus)) {
// Return one of the pre-approved error statuses
return EFI_DEVICE_ERROR;
}
}
// Read NOR Flash data into shadow buffer
TempStatus = NorFlashReadBlocks (Instance, Instance->StartLba + Lba, BlockSize, Instance->FvbBuffer);
if (EFI_ERROR (TempStatus)) {
// Return one of the pre-approved error statuses
return EFI_DEVICE_ERROR;
}
// Put the data at the appropriate location inside the buffer area
DEBUG ((DEBUG_BLKIO, "FvbRead: CopyMem( Dst=0x%08x, Src=0x%08x, Size=0x%x ).\n", Buffer, (UINTN)Instance->FvbBuffer + Offset, *NumBytes));
CopyMem (Buffer, (VOID*)((UINTN)Instance->FvbBuffer + Offset), *NumBytes);
return Status;
return EFI_SUCCESS;
}
/**
@@ -537,10 +531,21 @@ FvbWrite (
IN UINT8 *Buffer
)
{
EFI_STATUS Status;
EFI_STATUS TempStatus;
UINT32 Tmp;
UINT32 TmpBuf;
UINT32 WordToWrite;
UINT32 Mask;
UINTN DoErase;
UINTN BytesToWrite;
UINTN CurOffset;
UINTN WordAddr;
UINTN BlockSize;
NOR_FLASH_INSTANCE *Instance;
UINTN BlockAddress;
UINTN PrevBlockAddress;
PrevBlockAddress = 0;
Instance = INSTANCE_FROM_FVB_THIS(This);
@@ -550,9 +555,6 @@ FvbWrite (
DEBUG ((DEBUG_BLKIO, "FvbWrite(Parameters: Lba=%ld, Offset=0x%x, *NumBytes=0x%x, Buffer @ 0x%08x)\n", Instance->StartLba + Lba, Offset, *NumBytes, Buffer));
Status = EFI_SUCCESS;
TempStatus = Status;
// Detect WriteDisabled state
if (Instance->Media.ReadOnly == TRUE) {
DEBUG ((EFI_D_ERROR, "FvbWrite: ERROR - Can not write: Device is in WriteDisabled state.\n"));
@@ -578,7 +580,129 @@ FvbWrite (
return EFI_BAD_BUFFER_SIZE;
}
// Check we did get some memory
// Pick 128bytes as a good start for word operations as opposed to erasing the
// block and writing the data regardless if an erase is really needed.
// It looks like most individual NV variable writes are smaller than 128bytes.
if (*NumBytes <= 128) {
// Check to see if we need to erase before programming the data into NOR.
// If the destination bits are only changing from 1s to 0s we can just write.
// After a block is erased all bits in the block is set to 1.
// If any byte requires us to erase we just give up and rewrite all of it.
DoErase = 0;
BytesToWrite = *NumBytes;
CurOffset = Offset;
while (BytesToWrite > 0) {
// Read full word from NOR, splice as required. A word is the smallest
// unit we can write.
TempStatus = NorFlashRead (Instance, Instance->StartLba + Lba,
CurOffset & ~(0x3), sizeof(Tmp), &Tmp);
if (EFI_ERROR (TempStatus)) {
return EFI_DEVICE_ERROR;
}
// Physical address of word in NOR to write.
WordAddr = (CurOffset & ~(0x3)) + GET_NOR_BLOCK_ADDRESS (Instance->RegionBaseAddress,
Lba, BlockSize);
// The word of data that is to be written.
TmpBuf = *((UINT32*)(Buffer + (*NumBytes - BytesToWrite)));
// First do word aligned chunks.
if ((CurOffset & 0x3) == 0) {
if (BytesToWrite >= 4) {
// Is the destination still in 'erased' state?
if (~Tmp != 0) {
// Check to see if we are only changing bits to zero.
if ((Tmp ^ TmpBuf) & TmpBuf) {
DoErase = 1;
break;
}
}
// Write this word to NOR
WordToWrite = TmpBuf;
CurOffset += sizeof(TmpBuf);
BytesToWrite -= sizeof(TmpBuf);
} else {
// BytesToWrite < 4. Do small writes and left-overs
Mask = ~((~0) << (BytesToWrite * 8));
// Mask out the bytes we want.
TmpBuf &= Mask;
// Is the destination still in 'erased' state?
if ((Tmp & Mask) != Mask) {
// Check to see if we are only changing bits to zero.
if ((Tmp ^ TmpBuf) & TmpBuf) {
DoErase = 1;
break;
}
}
// Merge old and new data. Write merged word to NOR
WordToWrite = (Tmp & ~Mask) | TmpBuf;
CurOffset += BytesToWrite;
BytesToWrite = 0;
}
} else {
// Do multiple words, but starting unaligned.
if (BytesToWrite > (4 - (CurOffset & 0x3))) {
Mask = ~((~0) << ((CurOffset & 0x3) * 8));
// Mask out the bytes we want.
TmpBuf = (TmpBuf << ((CurOffset & 0x3) * 8)) & Mask;
// Is the destination still in 'erased' state?
if ((Tmp & Mask) != Mask) {
// Check to see if we are only changing bits to zero.
if ((Tmp ^ TmpBuf) & TmpBuf) {
DoErase = 1;
break;
}
}
// Merge old and new data. Write merged word to NOR
WordToWrite = (Tmp & ~Mask) | TmpBuf;
BytesToWrite -= (4 - (CurOffset & 0x3));
CurOffset += (4 - (CurOffset & 0x3));
} else {
// Unaligned and fits in one word.
Mask = (~((~0) << (BytesToWrite * 8))) << ((CurOffset & 0x3) * 8);
// Mask out the bytes we want.
TmpBuf = (TmpBuf << ((CurOffset & 0x3) * 8)) & Mask;
// Is the destination still in 'erased' state?
if ((Tmp & Mask) != Mask) {
// Check to see if we are only changing bits to zero.
if ((Tmp ^ TmpBuf) & TmpBuf) {
DoErase = 1;
break;
}
}
// Merge old and new data. Write merged word to NOR
WordToWrite = (Tmp & ~Mask) | TmpBuf;
CurOffset += BytesToWrite;
BytesToWrite = 0;
}
}
//
// Write the word to NOR.
//
BlockAddress = GET_NOR_BLOCK_ADDRESS (Instance->RegionBaseAddress, Lba, BlockSize);
if (BlockAddress != PrevBlockAddress) {
TempStatus = NorFlashUnlockSingleBlockIfNecessary (Instance, BlockAddress);
if (EFI_ERROR (TempStatus)) {
return EFI_DEVICE_ERROR;
}
PrevBlockAddress = BlockAddress;
}
TempStatus = NorFlashWriteSingleWord (Instance, WordAddr, WordToWrite);
if (EFI_ERROR (TempStatus)) {
return EFI_DEVICE_ERROR;
}
}
// Exit if we got here and could write all the data. Otherwise do the
// Erase-Write cycle.
if (!DoErase) {
return EFI_SUCCESS;
}
}
// Check we did get some memory. Buffer is BlockSize.
if (Instance->FvbBuffer == NULL) {
DEBUG ((EFI_D_ERROR, "FvbWrite: ERROR - Buffer not ready\n"));
return EFI_DEVICE_ERROR;
@@ -601,7 +725,7 @@ FvbWrite (
return EFI_DEVICE_ERROR;
}
return Status;
return EFI_SUCCESS;
}
/**