Re: [edk2-devel] [PATCH edk2-platforms v6 4/7] Platform/SbsaQemu: move FdtHandlerLib to SbsaQemuHardwareInfoLib

["Ard Biesheuvel" <ardb@kernel.org>]

On Wed, 6 Mar 2024 at 12:42, Marcin Juszkiewicz
<marcin.juszkiewicz@linaro.org> wrote:
>
> There is no need for EDK2 to know that there is DeviceTree around.
> All hardware information is read using functions from
> SbsaQemuHardwareInfoLib library.
>
> Library fallbacks to parsing DT if needed.
>

I'd prefer to have only a single method of obtaining this information.

> Signed-off-by: Marcin Juszkiewicz <marcin.juszkiewicz@linaro.org>
> Reviewed-by: Leif Lindholm <quic_llindhol@quicinc.com>
> ---
>  Platform/Qemu/SbsaQemu/SbsaQemu.dsc                 |   1 -
>  .../Drivers/SbsaQemuAcpiDxe/SbsaQemuAcpiDxe.inf     |   4 +-
>  .../SbsaQemu/Library/FdtHelperLib/FdtHelperLib.inf  |  33 -------
>  .../SbsaQemuHardwareInfoLib.inf                     |   2 +
>  .../Qemu/SbsaQemu/Include/Library/FdtHelperLib.h    |  36 -------
>  .../Drivers/SbsaQemuAcpiDxe/SbsaQemuAcpiDxe.c       |   4 +-
>  .../SbsaQemu/Library/FdtHelperLib/FdtHelperLib.c    |  98 ------------------
>  .../SbsaQemuHardwareInfoLib.c                       | 104 ++++++++++++++++++++
>  8 files changed, 110 insertions(+), 172 deletions(-)
>
> diff --git a/Platform/Qemu/SbsaQemu/SbsaQemu.dsc b/Platform/Qemu/SbsaQemu/SbsaQemu.dsc
> index 07cb3490f4cf..bde61651da2e 100644
> --- a/Platform/Qemu/SbsaQemu/SbsaQemu.dsc
> +++ b/Platform/Qemu/SbsaQemu/SbsaQemu.dsc
> @@ -126,7 +126,6 @@ [LibraryClasses.common]
>    # ARM PL011 UART Driver
>    PL011UartLib|ArmPlatformPkg/Library/PL011UartLib/PL011UartLib.inf
>
> -  FdtHelperLib|Silicon/Qemu/SbsaQemu/Library/FdtHelperLib/FdtHelperLib.inf
>    OemMiscLib|Platform/Qemu/SbsaQemu/OemMiscLib/OemMiscLib.inf
>    SbsaQemuHardwareInfoLib|Silicon/Qemu/SbsaQemu/Library/SbsaQemuHardwareInfoLib/SbsaQemuHardwareInfoLib.inf
>
> diff --git a/Silicon/Qemu/SbsaQemu/Drivers/SbsaQemuAcpiDxe/SbsaQemuAcpiDxe.inf b/Silicon/Qemu/SbsaQemu/Drivers/SbsaQemuAcpiDxe/SbsaQemuAcpiDxe.inf
> index 291743b19115..9bf0a13de5d1 100644
> --- a/Silicon/Qemu/SbsaQemu/Drivers/SbsaQemuAcpiDxe/SbsaQemuAcpiDxe.inf
> +++ b/Silicon/Qemu/SbsaQemu/Drivers/SbsaQemuAcpiDxe/SbsaQemuAcpiDxe.inf
> @@ -1,7 +1,7 @@
>  ## @file
>  #  This driver modifies ACPI tables for the Qemu SBSA platform
>  #
> -#  Copyright (c) 2020, Linaro Ltd. All rights reserved.
> +#  Copyright (c) Linaro Ltd. All rights reserved.
>  #
>  #  SPDX-License-Identifier: BSD-2-Clause-Patent
>  #
> @@ -35,9 +35,9 @@ [LibraryClasses]
>    BaseLib
>    DebugLib
>    DxeServicesLib
> -  FdtHelperLib
>    PcdLib
>    PrintLib
> +  SbsaQemuHardwareInfoLib
>    UefiDriverEntryPoint
>    UefiLib
>    UefiRuntimeServicesTableLib
> diff --git a/Silicon/Qemu/SbsaQemu/Library/FdtHelperLib/FdtHelperLib.inf b/Silicon/Qemu/SbsaQemu/Library/FdtHelperLib/FdtHelperLib.inf
> deleted file mode 100644
> index 9c059f3e5851..000000000000
> --- a/Silicon/Qemu/SbsaQemu/Library/FdtHelperLib/FdtHelperLib.inf
> +++ /dev/null
> @@ -1,33 +0,0 @@
> -#/** @file
> -#
> -#  Component description file for FdtHelperLib module
> -#
> -#  Copyright (c) 2021, NUVIA Inc. All rights reserved.
> -#
> -#  SPDX-License-Identifier: BSD-2-Clause-Patent
> -#
> -#**/
> -
> -[Defines]
> -  INF_VERSION                    = 1.29
> -  BASE_NAME                      = FdtHelperLib
> -  FILE_GUID                      = 34e4396f-c2fc-4f9e-ad58-0f98e99e3875
> -  MODULE_TYPE                    = BASE
> -  VERSION_STRING                 = 1.0
> -  LIBRARY_CLASS                  = FdtHelperLib
> -
> -[Sources.common]
> -  FdtHelperLib.c
> -
> -[Packages]
> -  EmbeddedPkg/EmbeddedPkg.dec
> -  MdePkg/MdePkg.dec
> -  Silicon/Qemu/SbsaQemu/SbsaQemu.dec
> -
> -[LibraryClasses]
> -  DebugLib
> -  FdtLib
> -  PcdLib
> -
> -[FixedPcd]
> -  gArmVirtSbsaQemuPlatformTokenSpaceGuid.PcdDeviceTreeBaseAddress
> diff --git a/Silicon/Qemu/SbsaQemu/Library/SbsaQemuHardwareInfoLib/SbsaQemuHardwareInfoLib.inf b/Silicon/Qemu/SbsaQemu/Library/SbsaQemuHardwareInfoLib/SbsaQemuHardwareInfoLib.inf
> index 8c2def1878e6..5358dd339eb3 100644
> --- a/Silicon/Qemu/SbsaQemu/Library/SbsaQemuHardwareInfoLib/SbsaQemuHardwareInfoLib.inf
> +++ b/Silicon/Qemu/SbsaQemu/Library/SbsaQemuHardwareInfoLib/SbsaQemuHardwareInfoLib.inf
> @@ -27,6 +27,8 @@ [LibraryClasses]
>    ArmSmcLib
>    BaseMemoryLib
>    DebugLib
> +  FdtLib
>
>   [Pcd]
> +  gArmVirtSbsaQemuPlatformTokenSpaceGuid.PcdDeviceTreeBaseAddress
>    gArmVirtSbsaQemuPlatformTokenSpaceGuid.PcdCoreCount
> diff --git a/Silicon/Qemu/SbsaQemu/Include/Library/FdtHelperLib.h b/Silicon/Qemu/SbsaQemu/Include/Library/FdtHelperLib.h
> deleted file mode 100644
> index ea9159857215..000000000000
> --- a/Silicon/Qemu/SbsaQemu/Include/Library/FdtHelperLib.h
> +++ /dev/null
> @@ -1,36 +0,0 @@
> -/** @file
> -*  FdtHelperLib.h
> -*
> -*  Copyright (c) 2021, NUVIA Inc. All rights reserved.
> -*
> -*  SPDX-License-Identifier: BSD-2-Clause-Patent
> -*
> -**/
> -
> -#ifndef FDT_HELPER_LIB_
> -#define FDT_HELPER_LIB_
> -
> -/**
> -  Get MPIDR for a given cpu from device tree passed by Qemu.
> -
> -  @param [in]   CpuId    Index of cpu to retrieve MPIDR value for.
> -
> -  @retval                MPIDR value of CPU at index <CpuId>
> -**/
> -UINT64
> -FdtHelperGetMpidr (
> -  IN UINTN   CpuId
> -  );
> -
> -/** Walks through the Device Tree created by Qemu and counts the number
> -    of CPUs present in it.
> -
> -    @return The number of CPUs present.
> -**/
> -EFIAPI
> -UINT32
> -FdtHelperCountCpus (
> -  VOID
> -  );
> -
> -#endif /* FDT_HELPER_LIB_ */
> diff --git a/Silicon/Qemu/SbsaQemu/Drivers/SbsaQemuAcpiDxe/SbsaQemuAcpiDxe.c b/Silicon/Qemu/SbsaQemu/Drivers/SbsaQemuAcpiDxe/SbsaQemuAcpiDxe.c
> index 59536ea9575e..03f7a34977a0 100644
> --- a/Silicon/Qemu/SbsaQemu/Drivers/SbsaQemuAcpiDxe/SbsaQemuAcpiDxe.c
> +++ b/Silicon/Qemu/SbsaQemu/Drivers/SbsaQemuAcpiDxe/SbsaQemuAcpiDxe.c
> @@ -15,10 +15,10 @@
>  #include <Library/ArmLib.h>
>  #include <Library/BaseMemoryLib.h>
>  #include <Library/DebugLib.h>
> -#include <Library/FdtHelperLib.h>
>  #include <Library/MemoryAllocationLib.h>
>  #include <Library/PcdLib.h>
>  #include <Library/PrintLib.h>
> +#include <Library/SbsaQemuHardwareInfoLib.h>
>  #include <Library/UefiBootServicesTableLib.h>
>  #include <Library/UefiDriverEntryPoint.h>
>  #include <Library/UefiLib.h>
> @@ -296,7 +296,7 @@ AddMadtTable (
>      CopyMem (New, &Gicc, sizeof (EFI_ACPI_6_0_GIC_STRUCTURE));
>      GiccPtr = (EFI_ACPI_6_0_GIC_STRUCTURE *) New;
>      GiccPtr->AcpiProcessorUid = CoreIndex;
> -    GiccPtr->MPIDR = FdtHelperGetMpidr (CoreIndex);
> +    GiccPtr->MPIDR = SbsaQemuGetMpidr (CoreIndex);
>      New += sizeof (EFI_ACPI_6_0_GIC_STRUCTURE);
>    }
>
> diff --git a/Silicon/Qemu/SbsaQemu/Library/FdtHelperLib/FdtHelperLib.c b/Silicon/Qemu/SbsaQemu/Library/FdtHelperLib/FdtHelperLib.c
> deleted file mode 100644
> index 7fdfb055db76..000000000000
> --- a/Silicon/Qemu/SbsaQemu/Library/FdtHelperLib/FdtHelperLib.c
> +++ /dev/null
> @@ -1,98 +0,0 @@
> -/** @file
> -*  FdtHelperLib.c
> -*
> -*  Copyright (c) 2021, NUVIA Inc. All rights reserved.
> -*  Copyright (c) 2020, Linaro Ltd. All rights reserved.
> -*
> -*  SPDX-License-Identifier: BSD-2-Clause-Patent
> -*
> -**/
> -
> -#include <Uefi.h>
> -#include <Library/DebugLib.h>
> -#include <Library/FdtHelperLib.h>
> -#include <Library/PcdLib.h>
> -#include <libfdt.h>
> -
> -STATIC INT32 mFdtFirstCpuOffset;
> -STATIC INT32 mFdtCpuNodeSize;
> -
> -/**
> -  Get MPIDR for a given cpu from device tree passed by Qemu.
> -
> -  @param [in]   CpuId    Index of cpu to retrieve MPIDR value for.
> -
> -  @retval                MPIDR value of CPU at index <CpuId>
> -**/
> -UINT64
> -FdtHelperGetMpidr (
> -  IN UINTN   CpuId
> -  )
> -{
> -  VOID           *DeviceTreeBase;
> -  CONST UINT64   *RegVal;
> -  INT32          Len;
> -
> -  DeviceTreeBase = (VOID *)(UINTN)PcdGet64 (PcdDeviceTreeBaseAddress);
> -  ASSERT (DeviceTreeBase != NULL);
> -
> -  RegVal = fdt_getprop (DeviceTreeBase,
> -             mFdtFirstCpuOffset + (CpuId * mFdtCpuNodeSize),
> -             "reg",
> -             &Len);
> -  if (!RegVal) {
> -    DEBUG ((DEBUG_ERROR, "Couldn't find reg property for CPU:%d\n", CpuId));
> -    return 0;
> -  }
> -
> -  return (fdt64_to_cpu (ReadUnaligned64 (RegVal)));
> -}
> -
> -/** Walks through the Device Tree created by Qemu and counts the number
> -    of CPUs present in it.
> -
> -    @return The number of CPUs present.
> -**/
> -EFIAPI
> -UINT32
> -FdtHelperCountCpus (
> -  VOID
> -  )
> -{
> -  VOID   *DeviceTreeBase;
> -  INT32  Node;
> -  INT32  Prev;
> -  INT32  CpuNode;
> -  UINT32 CpuCount;
> -
> -  DeviceTreeBase = (VOID *)(UINTN)PcdGet64 (PcdDeviceTreeBaseAddress);
> -  ASSERT (DeviceTreeBase != NULL);
> -
> -  // Make sure we have a valid device tree blob
> -  ASSERT (fdt_check_header (DeviceTreeBase) == 0);
> -
> -  CpuNode = fdt_path_offset (DeviceTreeBase, "/cpus");
> -  if (CpuNode <= 0) {
> -    DEBUG ((DEBUG_ERROR, "Unable to locate /cpus in device tree\n"));
> -    return 0;
> -  }
> -
> -  CpuCount = 0;
> -
> -  // Walk through /cpus node and count the number of subnodes.
> -  // The count of these subnodes corresponds to the number of
> -  // CPUs created by Qemu.
> -  Prev = fdt_first_subnode (DeviceTreeBase, CpuNode);
> -  mFdtFirstCpuOffset = Prev;
> -  while (1) {
> -    CpuCount++;
> -    Node = fdt_next_subnode (DeviceTreeBase, Prev);
> -    if (Node < 0) {
> -      break;
> -    }
> -    mFdtCpuNodeSize = Node - Prev;
> -    Prev = Node;
> -  }
> -
> -  return CpuCount;
> -}
> diff --git a/Silicon/Qemu/SbsaQemu/Library/SbsaQemuHardwareInfoLib/SbsaQemuHardwareInfoLib.c b/Silicon/Qemu/SbsaQemu/Library/SbsaQemuHardwareInfoLib/SbsaQemuHardwareInfoLib.c
> index 134fe73a5284..6315cce3fb7f 100644
> --- a/Silicon/Qemu/SbsaQemu/Library/SbsaQemuHardwareInfoLib/SbsaQemuHardwareInfoLib.c
> +++ b/Silicon/Qemu/SbsaQemu/Library/SbsaQemuHardwareInfoLib/SbsaQemuHardwareInfoLib.c
> @@ -11,8 +11,112 @@
>  #include <Library/DebugLib.h>
>  #include <Library/PcdLib.h>
>  #include <Library/SbsaQemuHardwareInfoLib.h>
> +#include <libfdt.h>
>  #include <IndustryStandard/SbsaQemuSmc.h>
>
> +/**
> +  Get MPIDR for a given cpu from device tree passed by Qemu.
> +
> +  @param [in]   CpuId    Index of cpu to retrieve MPIDR value for.
> +
> +  @retval                MPIDR value of CPU at index <CpuId>
> +**/
> +UINT64
> +FdtHelperGetMpidr (
> +  IN UINTN  CpuId
> +  )
> +{
> +  VOID          *DeviceTreeBase;
> +  INT32         Node;
> +  INT32         Prev;
> +  UINT32        CpuCount;
> +  CONST UINT64  *RegVal;
> +
> +  DeviceTreeBase = (VOID *)(UINTN)PcdGet64 (PcdDeviceTreeBaseAddress);
> +  ASSERT (DeviceTreeBase != NULL);
> +
> +  // Make sure we have a valid device tree blob
> +  ASSERT (fdt_check_header (DeviceTreeBase) == 0);
> +
> +  Node = fdt_path_offset (DeviceTreeBase, "/cpus");
> +  if (Node <= 0) {
> +    DEBUG ((DEBUG_ERROR, "Unable to locate /cpus in DeviceTree\n"));
> +    return 0;
> +  }
> +
> +  CpuCount = 0;
> +
> +  Prev = fdt_first_subnode (DeviceTreeBase, Node);
> +  while (1) {
> +    if (CpuCount == CpuId) {
> +      RegVal = fdt_getprop (DeviceTreeBase, Prev, "reg", NULL);
> +      if (!RegVal) {
> +        DEBUG ((DEBUG_ERROR, "Couldn't find reg property for CPU:%d\n", CpuId));
> +        return 0;
> +      }
> +
> +      return (fdt64_to_cpu (ReadUnaligned64 (RegVal)));
> +    }
> +
> +    Node = fdt_next_subnode (DeviceTreeBase, Prev);
> +    if (Node < 0) {
> +      break;
> +    }
> +
> +    Prev = Node;
> +    CpuCount++;
> +  }
> +
> +  return 0; /* We did not found MPIDR */
> +}
> +
> +/** Walks through the Device Tree created by Qemu and counts the number
> +    of CPUs present in it.
> +
> +    @return The number of CPUs present.
> +**/
> +EFIAPI
> +UINT32
> +FdtHelperCountCpus (
> +  VOID
> +  )
> +{
> +  VOID    *DeviceTreeBase;
> +  INT32   Node;
> +  INT32   Prev;
> +  UINT32  CpuCount;
> +
> +  DeviceTreeBase = (VOID *)(UINTN)PcdGet64 (PcdDeviceTreeBaseAddress);
> +  ASSERT (DeviceTreeBase != NULL);
> +
> +  // Make sure we have a valid device tree blob
> +  ASSERT (fdt_check_header (DeviceTreeBase) == 0);
> +
> +  Node = fdt_path_offset (DeviceTreeBase, "/cpus");
> +  if (Node <= 0) {
> +    DEBUG ((DEBUG_ERROR, "Unable to locate /cpus in DeviceTree\n"));
> +    return 0;
> +  }
> +
> +  CpuCount = 0;
> +
> +  // Walk through /cpus node and count the number of subnodes.
> +  // The count of these subnodes corresponds to the number of
> +  // CPUs created by Qemu.
> +  Prev = fdt_first_subnode (DeviceTreeBase, Node);
> +  while (1) {
> +    CpuCount++;
> +    Node = fdt_next_subnode (DeviceTreeBase, Prev);
> +    if (Node < 0) {
> +      break;
> +    }
> +
> +    Prev = Node;
> +  }
> +
> +  return CpuCount;
> +}
> +
>  /**
>    Get CPU count from information passed by Qemu.
>
>
> --
> 2.44.0
>


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