Re: [edk2-platforms PATCH] Platform/RaspberryPi: Add 'clock-frequency' property for miniuart

["Leif Lindholm" <leif@nuviainc.com>]

+Jeremy

On Fri, Jan 28, 2022 at 10:38:18 -0500, Adrien Thierry wrote:
> Describe the miniuart clock frequency in a _DSD property, so that it can
> be read from the Linux driver.
> 
> The miniuart clock frequency is the core clock frequency on the
> Raspberry Pi. It can be modified by the user using the 'core_freq'
> property in the config.txt file. So, we fetch it from the underlying
> Raspberry Pi firmware.
> 
> Signed-off-by: Adrien Thierry <athierry@redhat.com>
> ---
>  Platform/RaspberryPi/AcpiTables/Uart.asl           | 14 ++++++++++++++
>  Platform/RaspberryPi/Drivers/ConfigDxe/ConfigDxe.c |  9 +++++++++
>  .../RaspberryPi/Drivers/ConfigDxe/ConfigDxe.inf    |  1 +
>  Platform/RaspberryPi/RPi3/RPi3.dsc                 |  5 +++++
>  Platform/RaspberryPi/RPi4/RPi4.dsc                 |  5 +++++
>  Platform/RaspberryPi/RaspberryPi.dec               |  1 +
>  6 files changed, 35 insertions(+)
> 
> diff --git a/Platform/RaspberryPi/AcpiTables/Uart.asl b/Platform/RaspberryPi/AcpiTables/Uart.asl
> index 974f06d3bc..ef5165be98 100644
> --- a/Platform/RaspberryPi/AcpiTables/Uart.asl
> +++ b/Platform/RaspberryPi/AcpiTables/Uart.asl
> @@ -77,6 +77,20 @@ Device (URTM)
>      MEMORY32SETBASE (RBUF, RMEM, RBAS, BCM2836_MINI_UART_OFFSET)
>      Return (^RBUF)
>    }
> +
> +  //
> +  // Mini Uart Clock Rate will be dynamically updated during boot
> +  // 0x4D 0x55 0x43 0x52 0xC 0x1000000 (Value must be > 16777215)
> +  //
> +  Name (MUCR, 0x1000000)
> +
> +  Name (_DSD, Package ()
> +  {
> +    ToUUID ("daffd814-6eba-4d8c-8a91-bc9bbf4aa301"), Package ()
> +    {
> +      Package (2) { "clock-frequency", MUCR },
> +    }
> +  })
>  }
>  
>  //
> diff --git a/Platform/RaspberryPi/Drivers/ConfigDxe/ConfigDxe.c b/Platform/RaspberryPi/Drivers/ConfigDxe/ConfigDxe.c
> index 415d99fadb..3dcf2bac0d 100644
> --- a/Platform/RaspberryPi/Drivers/ConfigDxe/ConfigDxe.c
> +++ b/Platform/RaspberryPi/Drivers/ConfigDxe/ConfigDxe.c
> @@ -44,6 +44,7 @@ STATIC RASPBERRY_PI_FIRMWARE_PROTOCOL *mFwProtocol;
>  STATIC UINT32 mModelFamily = 0;
>  STATIC UINT32 mModelInstalledMB = 0;
>  STATIC UINT32 mModelRevision = 0;
> +STATIC UINT32 mCoreClockRate = 0;
>  
>  STATIC EFI_MAC_ADDRESS  mMacAddress;
>  
> @@ -798,6 +799,7 @@ STATIC CONST AML_NAME_OP_REPLACE SsdtEmmcNameOpReplace[] = {
>  
>  STATIC CONST AML_NAME_OP_REPLACE DsdtNameOpReplace[] = {
>    { "URIU", PcdToken (PcdUartInUse) },
> +  { "MUCR", PcdToken (PcdMiniUartClockRate) },
>    { }
>  };
>  
> @@ -944,6 +946,13 @@ ConfigInitialize (
>      DEBUG ((DEBUG_INFO, "Current Raspberry Pi revision %x\n", mModelRevision));
>    }
>  
> +  Status = mFwProtocol->GetClockRate (RPI_MBOX_CLOCK_RATE_CORE, &mCoreClockRate);
> +  if (Status != EFI_SUCCESS) {
> +    DEBUG ((DEBUG_ERROR, "Couldn't get the Raspberry Pi core clock rate: %r\n", Status));
> +  } else {
> +    PcdSet32S (PcdMiniUartClockRate, mCoreClockRate);
> +  }
> +
>    Status = SetupVariables ();
>    if (Status != EFI_SUCCESS) {
>      DEBUG ((DEBUG_ERROR, "Couldn't not setup NV vars: %r\n", Status));
> diff --git a/Platform/RaspberryPi/Drivers/ConfigDxe/ConfigDxe.inf b/Platform/RaspberryPi/Drivers/ConfigDxe/ConfigDxe.inf
> index e6e22ad82e..6f6e8f42ac 100644
> --- a/Platform/RaspberryPi/Drivers/ConfigDxe/ConfigDxe.inf
> +++ b/Platform/RaspberryPi/Drivers/ConfigDxe/ConfigDxe.inf
> @@ -95,6 +95,7 @@
>    gRaspberryPiTokenSpaceGuid.PcdFanTemp
>    gRaspberryPiTokenSpaceGuid.PcdUartInUse
>    gRaspberryPiTokenSpaceGuid.PcdXhciPci
> +  gRaspberryPiTokenSpaceGuid.PcdMiniUartClockRate
>  
>  [Depex]
>    gPcdProtocolGuid AND gRaspberryPiFirmwareProtocolGuid
> diff --git a/Platform/RaspberryPi/RPi3/RPi3.dsc b/Platform/RaspberryPi/RPi3/RPi3.dsc
> index 6ab5d1ae6d..6dc48dc233 100644
> --- a/Platform/RaspberryPi/RPi3/RPi3.dsc
> +++ b/Platform/RaspberryPi/RPi3/RPi3.dsc
> @@ -561,6 +561,11 @@
>    #
>    gRaspberryPiTokenSpaceGuid.PcdUartInUse|1
>  
> +  #
> +  # Mini-UART clock rate
> +  #
> +  gRaspberryPiTokenSpaceGuid.PcdMiniUartClockRate|250000000
> +
>  ################################################################################
>  #
>  # Components Section - list of all EDK II Modules needed by this Platform
> diff --git a/Platform/RaspberryPi/RPi4/RPi4.dsc b/Platform/RaspberryPi/RPi4/RPi4.dsc
> index 44ed60ab2f..a9c0c36bb1 100644
> --- a/Platform/RaspberryPi/RPi4/RPi4.dsc
> +++ b/Platform/RaspberryPi/RPi4/RPi4.dsc
> @@ -580,6 +580,11 @@
>    #
>    gRaspberryPiTokenSpaceGuid.PcdUartInUse|0
>  
> +  #
> +  # Mini-UART clock rate
> +  #
> +  gRaspberryPiTokenSpaceGuid.PcdMiniUartClockRate|500000000
> +
>  ################################################################################
>  #
>  # Components Section - list of all EDK II Modules needed by this Platform
> diff --git a/Platform/RaspberryPi/RaspberryPi.dec b/Platform/RaspberryPi/RaspberryPi.dec
> index 797be59274..17b6061a05 100644
> --- a/Platform/RaspberryPi/RaspberryPi.dec
> +++ b/Platform/RaspberryPi/RaspberryPi.dec
> @@ -72,3 +72,4 @@
>    gRaspberryPiTokenSpaceGuid.PcdMmcEnableDma|0|UINT32|0x0000001F
>    gRaspberryPiTokenSpaceGuid.PcdUartInUse|1|UINT32|0x00000021
>    gRaspberryPiTokenSpaceGuid.PcdXhciPci|0|UINT32|0x00000022
> +  gRaspberryPiTokenSpaceGuid.PcdMiniUartClockRate|0|UINT32|0x00000023
> -- 
> 2.17.1
>