Re: [PATCH edk2-platforms 5/5] Platform/RaspberryPi: create DXE phase SerialPortLib version for RPi3

["Pete Batard" <pete@akeo.ie>]

On 2020.05.05 15:50, Ard Biesheuvel wrote:
> The Raspberry Pi 3 derives its 16550 baud clock from the variable core
> clock, and so any reprogramming of the baud rate needs to take the
> actual core clock value into account.
> 
> Introduce a DXE phase version of DualSerialPortLib that discovers this
> value in its constructor, using the RPi firmware protocol, and wire it
> up for the RPi3 platform.
> 
> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@arm.com>
> ---
>   Platform/RaspberryPi/RPi3/RPi3.dsc                                            |  2 +-
>   Platform/RaspberryPi/Library/DualSerialPortLib/DualSerialPortDxeLib.inf       | 67 ++++++++++++++++++++
>   Platform/RaspberryPi/Library/DualSerialPortLib/DualSerialPortLibConstructor.c | 40 ++++++++++++
>   3 files changed, 108 insertions(+), 1 deletion(-)
> 
> diff --git a/Platform/RaspberryPi/RPi3/RPi3.dsc b/Platform/RaspberryPi/RPi3/RPi3.dsc
> index 96b27400eef8..2b8ad1c4bdbd 100644
> --- a/Platform/RaspberryPi/RPi3/RPi3.dsc
> +++ b/Platform/RaspberryPi/RPi3/RPi3.dsc
> @@ -576,7 +576,7 @@ [Components.common]
>     MdeModulePkg/Universal/Console/TerminalDxe/TerminalDxe.inf
>     MdeModulePkg/Universal/SerialDxe/SerialDxe.inf {
>       <LibraryClasses>
> -      SerialPortLib|Platform/RaspberryPi/Library/DualSerialPortLib/DualSerialPortLib.inf
> +      SerialPortLib|Platform/RaspberryPi/Library/DualSerialPortLib/DualSerialPortDxeLib.inf
>     }
>     Platform/RaspberryPi/Drivers/DisplayDxe/DisplayDxe.inf
>   
> diff --git a/Platform/RaspberryPi/Library/DualSerialPortLib/DualSerialPortDxeLib.inf b/Platform/RaspberryPi/Library/DualSerialPortLib/DualSerialPortDxeLib.inf
> new file mode 100644
> index 000000000000..4c22b39daa7f
> --- /dev/null
> +++ b/Platform/RaspberryPi/Library/DualSerialPortLib/DualSerialPortDxeLib.inf
> @@ -0,0 +1,67 @@
> +## @file
> +#
> +#  DXE phase SerialPortLib instance for both PL011 and 16550 UART.
> +#
> +#  Copyright (c) 2020, Pete Batard <pete@akeo.ie>
> +#  Copyright (c) 2006 - 2019, Intel Corporation. All rights reserved.<BR>
> +#
> +#  SPDX-License-Identifier: BSD-2-Clause-Patent
> +#
> +##
> +
> +[Defines]
> +  INF_VERSION                    = 1.27
> +  BASE_NAME                      = DualSerialPortDxeLib
> +  FILE_GUID                      = d586667e-ec50-4bf6-9701-fb4e29055a60
> +  MODULE_TYPE                    = DXE_DRIVER
> +  VERSION_STRING                 = 1.0
> +  LIBRARY_CLASS                  = SerialPortLib|DXE_DRIVER
> +  CONSTRUCTOR                    = DualSerialPortDxeLibConstructor
> +
> +[Packages]
> +  ArmPlatformPkg/ArmPlatformPkg.dec
> +  MdeModulePkg/MdeModulePkg.dec
> +  MdePkg/MdePkg.dec
> +  Platform/RaspberryPi/RaspberryPi.dec
> +  Silicon/Broadcom/Bcm283x/Bcm283x.dec
> +
> +[LibraryClasses]
> +  IoLib
> +  PcdLib
> +  PL011UartClockLib
> +  PL011UartLib
> +
> +[Sources]
> +  DualSerialPortLib.c
> +  DualSerialPortLib.h
> +  DualSerialPortLibCommon.c
> +  DualSerialPortLibConstructor.c
> +
> +[Pcd]
> +  gEfiMdeModulePkgTokenSpaceGuid.PcdSerialRegisterAccessWidth     ## SOMETIMES_CONSUMES
> +  gEfiMdeModulePkgTokenSpaceGuid.PcdSerialUseMmio                 ## CONSUMES
> +  gEfiMdeModulePkgTokenSpaceGuid.PcdSerialUseHardwareFlowControl  ## CONSUMES
> +  gEfiMdeModulePkgTokenSpaceGuid.PcdSerialDetectCable             ## SOMETIMES_CONSUMES
> +  gEfiMdeModulePkgTokenSpaceGuid.PcdSerialBaudRate                ## CONSUMES
> +  gEfiMdeModulePkgTokenSpaceGuid.PcdSerialLineControl             ## CONSUMES
> +  gEfiMdeModulePkgTokenSpaceGuid.PcdSerialFifoControl             ## CONSUMES
> +  gEfiMdeModulePkgTokenSpaceGuid.PcdSerialPciDeviceInfo           ## CONSUMES
> +  gEfiMdeModulePkgTokenSpaceGuid.PcdSerialExtendedTxFifoSize      ## CONSUMES
> +  gEfiMdeModulePkgTokenSpaceGuid.PcdSerialRegisterStride          ## CONSUMES
> +
> +[FixedPcd]
> +  gArmPlatformTokenSpaceGuid.PL011UartClkInHz
> +  gBcm283xTokenSpaceGuid.PcdBcm283xRegistersAddress
> +  gEfiMdePkgTokenSpaceGuid.PcdUartDefaultBaudRate
> +  gEfiMdePkgTokenSpaceGuid.PcdUartDefaultDataBits
> +  gEfiMdePkgTokenSpaceGuid.PcdUartDefaultParity
> +  gEfiMdePkgTokenSpaceGuid.PcdUartDefaultStopBits
> +
> +[Protocols]
> +  gRaspberryPiFirmwareProtocolGuid                                ## CONSUMES
> +
> +[PatchPcd]
> +  gEfiMdeModulePkgTokenSpaceGuid.PcdSerialClockRate               ## CONSUMES
> +
> +[Depex]
> +  gRaspberryPiFirmwareProtocolGuid
> diff --git a/Platform/RaspberryPi/Library/DualSerialPortLib/DualSerialPortLibConstructor.c b/Platform/RaspberryPi/Library/DualSerialPortLib/DualSerialPortLibConstructor.c
> new file mode 100644
> index 000000000000..c6d695181ab7
> --- /dev/null
> +++ b/Platform/RaspberryPi/Library/DualSerialPortLib/DualSerialPortLibConstructor.c
> @@ -0,0 +1,40 @@
> +/** @file
> +
> +  Copyright (c) 2020, ARM Ltd. All rights reserved.<BR>
> +
> +  SPDX-License-Identifier: BSD-2-Clause-Patent
> +
> +**/
> +
> +#include <Uefi.h>
> +#include <IndustryStandard/RpiMbox.h>
> +#include <Library/SerialPortLib.h>
> +#include <Library/PcdLib.h>
> +#include <Protocol/RpiFirmware.h>
> +
> +EFI_STATUS
> +EFIAPI
> +DualSerialPortDxeLibConstructor (
> +  IN EFI_HANDLE         ImageHandle,
> +  IN EFI_SYSTEM_TABLE   *SystemTable
> +  )
> +{
> +  RASPBERRY_PI_FIRMWARE_PROTOCOL    *Firmware;
> +  UINT32                            ClockRate;
> +  EFI_STATUS                        Status;
> +
> +  Status = SystemTable->BootServices->LocateProtocol (
> +                                        &gRaspberryPiFirmwareProtocolGuid,
> +                                        NULL, (VOID **)&Firmware);
> +  if (EFI_ERROR (Status)) {
> +    return Status;
> +  }
> +
> +  Status = Firmware->GetClockRate (RPI_MBOX_CLOCK_RATE_CORE, &ClockRate);
> +  if (EFI_ERROR (Status)) {
> +    return Status;
> +  }
> +
> +  PatchPcdSet32 (PcdSerialClockRate, ClockRate);
> +  return EFI_SUCCESS;
> +}
> 

Reviewed-by: Pete Batard <pete@akeo.ie>

For the series:
Tested-by: Pete Batard <pete@akeo.ie>
Tested-on-platforms: RPi3 Model B+, RPi4 Model B