Re: [edk2-devel] [PATCH RESEND edk2-platforms][PATCH V2 11/14] Silicon/ARM/NeoverseN1Soc: NOR flash library for N1Sdp

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

Hi Sami,
Thank you for reviewing the patches.
Please find my comments inline below marked as [SAHIL].

On Thu, 16 May 2024 at 20:54, Sami Mujawar via groups.io
<sami.mujawar=arm.com@groups.io> wrote:
>
> Hi Sahil,
>
> Thank you for this patch.
>
> I have some suggestions marked inline below, otherwise this patch looks good to me.
>
> With that fixed,
>
> Reviewed-by: Sami Mujawar <sami.mujawar@arm.com>
>
> Regards,
>
> Sami Mujawar
>
> On 23/04/2024 06:56 am, Sahil Kaushal wrote:
>
> From: sahil <sahil@arm.com>
>
> Add NOR flash library, this library provides APIs for getting the list
> of NOR flash devices on the platform.
>
> [SAMI] I think the information in the commit message of patch 10/14 would be more useful here.
>
> Not mandatory, but it may be useful to have an ASCII diagram to explain the flash partitioning.
>
> [/SAMI]

[SAHIL]
I will add more information to the commit message.
As for the ASCII diagram, as the size of the images can change, it
will not be possible to make an accurate diagram.
[/SAHIL]

>
> Signed-off-by: sahil <sahil@arm.com>
> ---
>  Silicon/ARM/NeoverseN1Soc/Library/NorFlashLib/NorFlashLib.inf | 34 ++++++++++
>  Silicon/ARM/NeoverseN1Soc/Library/NorFlashLib/NorFlashLib.c   | 65 ++++++++++++++++++++
>  2 files changed, 99 insertions(+)
>
> diff --git a/Silicon/ARM/NeoverseN1Soc/Library/NorFlashLib/NorFlashLib.inf b/Silicon/ARM/NeoverseN1Soc/Library/NorFlashLib/NorFlashLib.inf
> new file mode 100644
> index 000000000000..fad3bca79d3a
> --- /dev/null
> +++ b/Silicon/ARM/NeoverseN1Soc/Library/NorFlashLib/NorFlashLib.inf
> @@ -0,0 +1,34 @@
> +## @file
>
> +#  NOR flash lib for ARM Neoverse N1 platform.
>
> +#
>
> +#  Copyright (c) 2024, ARM Limited. All rights reserved.<BR>
>
> +#
>
> +#  SPDX-License-Identifier: BSD-2-Clause-Patent
>
> +#
>
> +##
>
> +
>
> +[Defines]
>
> +  INF_VERSION                    = 0x0001001B
>
> +  BASE_NAME                      = NorFlashNeoverseN1SocLib
>
> +  FILE_GUID                      = 7006fcf1-a585-4272-92e3-b286b1dff5bb
>
> +  MODULE_TYPE                    = DXE_DRIVER
>
> +  VERSION_STRING                 = 1.0
>
> +  LIBRARY_CLASS                  = NorFlashPlatformLib
>
> +
>
> +[Sources.common]
>
> +  NorFlashLib.c
>
> +
>
> +[Packages]
>
> +  MdeModulePkg/MdeModulePkg.dec
>
> +  MdePkg/MdePkg.dec
>
> +  Platform/ARM/ARM.dec
>
> +  Silicon/ARM/NeoverseN1Soc/NeoverseN1Soc.dec
>
> +
>
> +[LibraryClasses]
>
> +  BaseLib
>
> +
>
> +[FixedPcd]
>
> +  gEfiMdeModulePkgTokenSpaceGuid.PcdFlashNvStorageFtwSpareSize
>
> +  gEfiMdeModulePkgTokenSpaceGuid.PcdFlashNvStorageFtwWorkingSize
>
> +  gEfiMdeModulePkgTokenSpaceGuid.PcdFlashNvStorageVariableBase
>
> +  gEfiMdeModulePkgTokenSpaceGuid.PcdFlashNvStorageVariableSize
>
> diff --git a/Silicon/ARM/NeoverseN1Soc/Library/NorFlashLib/NorFlashLib.c b/Silicon/ARM/NeoverseN1Soc/Library/NorFlashLib/NorFlashLib.c
> new file mode 100644
> index 000000000000..a48db9c74548
> --- /dev/null
> +++ b/Silicon/ARM/NeoverseN1Soc/Library/NorFlashLib/NorFlashLib.c
> @@ -0,0 +1,65 @@
> +/** @file
>
> +*  NOR flash lib for ARM Neoverse N1 platform
>
> +*
>
> +*  Copyright (c) 2024, ARM Limited. All rights reserved.<BR>
>
> +*
>
> +*  SPDX-License-Identifier: BSD-2-Clause-Patent
>
> +*
>
> +**/
>
> +
>
> +#include <Library/NorFlashPlatformLib.h>
>
> +#include <NeoverseN1Soc.h>
>
> +#include <PiDxe.h>
>
> +
>
> +#define FW_ENV_REGION_BASE  FixedPcdGet32 (PcdFlashNvStorageVariableBase)
>
> +#define FW_ENV_REGION_SIZE  (FixedPcdGet32 (PcdFlashNvStorageVariableSize) + \
>
> +                            FixedPcdGet32 (PcdFlashNvStorageFtwWorkingSize) + \
>
> +                            FixedPcdGet32 (PcdFlashNvStorageFtwSpareSize))
>
> [SAMI] Would it be an issue if someone were to increase the storage variable sizes above?
>
> How can you prevent someone overwriting the flash region used by the SCP?
>
> Would it make sense to add a check in NorFlashPlatformInitialization() ?
>
> [/SAMI]

[SAHIL]
With the current code, the firmware images take ~2.5MB and the
variable storage region starts at 15MB
offset from the base. The firmware image's size is unlikely to change much.
Therefore, it is unlikely to cause any issue if someone tries to
increase the variable
region by decreasing the PcdFlashNvStorageVariableBase.

If we still want to add a check, I can add an assert checking
PcdFlashNvStorageVariableBase offset is
not <= to a particular offset (maybe 8MB) in NorFlashPlatformInitialization().
Would this be fine?
[/SAHIL]

>
> +
>
> +STATIC NOR_FLASH_DESCRIPTION  mNorFlashDevices[] = {
>
> +  {
>
> +    /// Environment variable region
>
> +    NEOVERSEN1SOC_SCP_QSPI_AHB_BASE,                    ///< device base
>
> +    FW_ENV_REGION_BASE,                                 ///< region base
>
> +    FW_ENV_REGION_SIZE,                                 ///< region size
>
> +    SIZE_4KB,                                           ///< block size
>
> +  },
>
> +};
>
> +
>
> +/**
>
> +  Dummy implementation of NorFlashPlatformInitialization to
>
> +  comply with NorFlashPlatformLib structure.
>
> +
>
> +  @retval        EFI_SUCCESS        Success.
>
> +**/
>
> +EFI_STATUS
>
> +NorFlashPlatformInitialization (
>
> +  VOID
>
> +  )
>
> +{
>
> +  return EFI_SUCCESS;
>
> +}
>
> +
>
> +/**
>
> +  Get NOR flash region info
>
> +
>
> +  @param[out]    NorFlashDevices        NOR flash regions info.
>
> +  @param[out]    Count                  number of flash instance.
>
> +
>
> +  @retval        EFI_SUCCESS            Success.
>
> +  @retval        EFI_INVALID_PARAMETER  The parameters specified are not valid.
>
> +**/
>
> +EFI_STATUS
>
> +NorFlashPlatformGetDevices (
>
> +  OUT NOR_FLASH_DESCRIPTION  **NorFlashDevices,
>
> +  OUT UINT32                 *Count
>
> +  )
>
> +{
>
> +  if ((NorFlashDevices == NULL) || (Count == NULL)) {
>
> +    return EFI_INVALID_PARAMETER;
>
> +  }
>
> +
>
> +  *NorFlashDevices = mNorFlashDevices;
>
> +  *Count           = ARRAY_SIZE (mNorFlashDevices);
>
> +  return EFI_SUCCESS;
>
> +}
>
> 


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