Re: [edk2-devel] [PATCH RESEND edk2-platforms][PATCH V2 12/14] Platform/ARM: Add CadenceQspiNorFlashDeviceLib for NorFlashDxe

["sahil" <sahil@arm.com>]

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Hi Pierre, Thanks for reviewing the patchset. Please find my comment inline
below.

On Thu, 2 May 2024 at 18:47, PierreGondois via groups.io <pierre.gondois=
arm.com@groups.io> wrote:
>
> Hello Sahil,
>
> On 4/23/24 07:56, Sahil Kaushal via groups.io wrote:
> > From: sahil <sahil@arm.com>
> >
> > In N1Sdp platform, the SoC is connected to IOFPGA which has a
> > Cadence Quad SPI (QSPI) controller. This QSPI controller manages
> > the flash chip device via QSPI bus.
> >
> > This patch adds CadenceQspiNorFlashDeviceLib which is used to
> > manage and access the above configuration.
> >
> > Signed-off-by: sahil <sahil@arm.com>
> > ---
> >
Platform/ARM/Library/CadenceQspiNorFlashDeviceLib/CadenceQspiNorFlashDeviceLib.inf
|   32 +
> >
Platform/ARM/Library/CadenceQspiNorFlashDeviceLib/CadenceQspiNorFlashDeviceLib.h
  |   44 +
> >
Platform/ARM/Library/CadenceQspiNorFlashDeviceLib/CadenceQspiNorFlashDeviceLib.c
  | 1011 ++++++++++++++++++++
> >   3 files changed, 1087 insertions(+)
> >
>
> [snip]
>
> > +
> > +/**
> > +  Converts milliseconds into number of ticks of the performance
counter.
> > +
> > +  @param[in] Milliseconds  Milliseconds to convert into ticks.
> > +
> > +  @retval Milliseconds expressed as number of ticks.
> > +
> > +**/
> > +STATIC
> > +UINT64
> > +MilliSecondsToTicks (
> > +  IN UINTN  Milliseconds
> > +  )
> > +{
> > +  CONST UINT64  NanoSecondsPerTick = GetTimeInNanoSecond (1);
> > +
> > +  return (Milliseconds * 1000000) / NanoSecondsPerTick;
>
> Should use DivU64x64Remainder() here:
> {
>    UINT64  NanoSecondsPerTick;
>    UINT64  NanoSeconds;
>
>    NanoSecondsPerTick = GetTimeInNanoSecond (1);
>    NanoSeconds = MultU64x32 (Milliseconds, 1000000);
>
>    return DivU64x64Remainder (NanoSeconds, NanoSecondsPerTick, NULL);
> }
>
> > +}
> > +
> > +/**
> > +  Poll Status register for NOR flash erase/write completion.
> > +
> > +  @param[in]      Instance           NOR flash Instance.
> > +
> > +  @retval         EFI_SUCCESS        Request is executed successfully.
> > +  @retval         EFI_TIMEOUT        Operation timed out.
> > +  @retval         EFI_DEVICE_ERROR   Controller operartion failed.
>
> operartion -> typo
> (same at another place I think)
>
> [snip]
>
> > +
> > +/**
> > +  Read from nor flash.
> > +
> > +  @param[in]     Instance               NOR flash Instance of variable
store region.
> > +  @param[in]     Lba                    The starting logical block
index to read from.
> > +  @param[in]     Offset                 Offset into the block at which
to begin reading.
> > +  @param[in]     BufferSizeInBytes      The number of bytes to read.
> > +  @param[out]    Buffer                 The pointer to a
caller-allocated buffer that
> > +                                        should copied with read data.
> > +
> > +  @retval        EFI_SUCCESS            The read is completed.
> > +  @retval        EFI_INVALID_PARAMETER  Invalid parameters passed.
> > +**/
> > +EFI_STATUS
> > +NorFlashRead (
> > +  IN NOR_FLASH_INSTANCE  *Instance,
> > +  IN EFI_LBA             Lba,
> > +  IN UINTN               Offset,
> > +  IN UINTN               BufferSizeInBytes,
> > +  OUT VOID               *Buffer
> > +  )
> > +{
> > +  UINTN  StartAddress;
> > +
> > +  // The buffer must be valid
> > +  if (Buffer == NULL) {
> > +    return EFI_INVALID_PARAMETER;
> > +  }
> > +
> > +  // Return if we do not have any byte to read
> > +  if (BufferSizeInBytes == 0) {
> > +    return EFI_SUCCESS;
> > +  }
> > +
> > +  if (((Lba * Instance->Media.BlockSize) + Offset + BufferSizeInBytes)
>
> > +      Instance->Size)
> > +  {
> > +    DEBUG ((
> > +      DEBUG_ERROR,
> > +      "NorFlashRead: ERROR - Read will exceed device size.\n"
> > +      ));
> > +    return EFI_INVALID_PARAMETER;
> > +  }
> > +
> > +  // Get the address to start reading from
> > +  StartAddress = GET_NOR_BLOCK_ADDRESS (
> > +                   Instance->RegionBaseAddress,
> > +                   Lba,
> > +                   Instance->Media.BlockSize
> > +                   );
> > +
> > +  // Readout the data
> > +  CopyMem (Buffer, (UINTN *)(StartAddress + Offset),
BufferSizeInBytes);
>
> The original code at:
>    Platform/ARM/Library/P30NorFlashDeviceLib/P30NorFlashDeviceLib.c
>
> implements and uses AlignedCopyMem()/NorFlashWriteBuffer() which seems
> to be more efficient.
> Just to be sure I understand correctly, is the maximal read/write size
> of 4 bytes ? Meaning that these functions are not needed ?
>
> ---
>
> NorFlashWriteBuffer() is not implemented here IIUC won't be implemtned as
not
> needed. Maybe in an additional patch, the function could be removed from
the
> library interface at:
>    Platform/ARM/Include/Library/NorFlashDeviceLib.h
> and made static in:
>    Platform/ARM/Library/P30NorFlashDeviceLib/P30NorFlashDeviceLib.c
>
CopyMem() and AlignedCopyMem() have nearly identical implementations,
therefore I think we can
continue using CopyMem() here.

For NorFlashWriteBuffer(), in the P30 spec, it looks like buffered
programming is one of the features
of the IP whereas there is no such feature in cadence IP. So, I think there
is no need for
NorFlashWriteBuffer() for Cadence controller Library.

I will push another patch in the next patchset to remove
 NorFlashWriteBuffer() from the
NorFlashDeviceLib.h header file.

> > +
> > +  return EFI_SUCCESS;
> > +}
> > +
> > +/**
> > +  Write a full or portion of a block.
> > +
> > +  @param[in]       Instance              NOR flash Instance of
variable store region.
> > +  @param[in]       Lba                   The starting logical block
index to write to.
> > +  @param[in]       Offset                Offset into the block at
which to begin writing.
> > +  @param[in, out]  NumBytes              The total size of the buffer.
> > +  @param[in]       Buffer                The pointer to a
caller-allocated buffer that
> > +                                         contains the source for the
write.
> > +
> > +  @retval          EFI_SUCCESS           The write is completed.
> > +  @retval          EFI_OUT_OF_RESOURCES  Invalid Buffer passed.
> > +  @retval          EFI_BAD_BUFFER_SIZE   Buffer size not enough.
> > +  @retval          EFI_DEVICE_ERROR      The device reported an error.
> > +**/
> > +EFI_STATUS
> > +NorFlashWriteSingleBlock (
> > +  IN        NOR_FLASH_INSTANCE  *Instance,
> > +  IN        EFI_LBA             Lba,
> > +  IN        UINTN               Offset,
> > +  IN OUT    UINTN               *NumBytes,
> > +  IN        UINT8               *Buffer
> > +  )
> > +{
> > +  EFI_STATUS  Status;
> > +  UINT32      Tmp;
> > +  UINT32      TmpBuf;
> > +  UINT32      WordToWrite;
> > +  UINT32      Mask;
> > +  BOOLEAN     DoErase;
> > +  UINTN       BytesToWrite;
> > +  UINTN       CurOffset;
> > +  UINTN       WordAddr;
> > +  UINTN       BlockSize;
> > +  UINTN       BlockAddress;
> > +  UINTN       PrevBlockAddress;
> > +
> > +  if (Buffer == NULL) {
> > +    DEBUG ((
> > +      DEBUG_ERROR,
> > +      "NorFlashWriteSingleBlock: ERROR - Buffer is invalid\n"
> > +      ));
> > +    return EFI_OUT_OF_RESOURCES;
>
> EFI_INVALID_PARAMETER instead I think
>
> > +  }
> > +
> > +  PrevBlockAddress = 0;
> > +
> > +  DEBUG ((
> > +    DEBUG_INFO,
> > +    "NorFlashWriteSingleBlock(Parameters: Lba=%ld, Offset=0x%x, "
> > +    "*NumBytes=0x%x, Buffer @ 0x%08x)\n",
> > +    Lba,
> > +    Offset,
> > +    *NumBytes,
> > +    Buffer
> > +    ));
> > +
> > +  // Localise the block size to avoid de-referencing pointers all the
time
>
> Localise -> Locate
>
> > +  BlockSize = Instance->Media.BlockSize;
> > +
>
> [snip]
>
>
> 
>
>


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