On Fri, 2 Apr 2021 at 19:52, Mario Bălănică <mariobalanic...@gmail.com> wrote:
>
> The baud rate divisor calculation for mini UART on BCM2711 is the same
> as on older models since this commit:
> https://github.com/raspberrypi/firmware/commit/1e5456a
>
> Signed-off-by: Mario Bălănică <mariobalanic...@gmail.com>
Doesn't this make the new build incompatible with the old firmware? Is
there a way to support both?
> ---
> Platform/RaspberryPi/Library/DualSerialPortLib/DualSerialPortLib.c | 15
> +++------------
> Platform/RaspberryPi/Library/PlatformLib/AArch64/RaspberryPiHelper.S | 4
> ----
> Platform/RaspberryPi/RPi4/RPi4.dsc | 6
> ++++--
> 3 files changed, 7 insertions(+), 18 deletions(-)
>
> diff --git
> a/Platform/RaspberryPi/Library/DualSerialPortLib/DualSerialPortLib.c
> b/Platform/RaspberryPi/Library/DualSerialPortLib/DualSerialPortLib.c
> index 5e83bbf022eb..d2f983bf0a9f 100644
> --- a/Platform/RaspberryPi/Library/DualSerialPortLib/DualSerialPortLib.c
> +++ b/Platform/RaspberryPi/Library/DualSerialPortLib/DualSerialPortLib.c
> @@ -34,25 +34,16 @@ SerialPortGetDivisor (
> UINT32 SerialBaudRate
> )
> {
> - UINT64 BaseClockRate;
> + UINT32 BaseClockRate;
> UINT32 Divisor;
>
> - //
> - // On the Raspberry Pi, the clock to use for the 16650-compatible UART
> - // is the base clock divided by the 12.12 fixed point VPU clock divisor.
> - //
> - BaseClockRate = (UINT64)PcdGet32 (PcdSerialClockRate);
> -#if (RPI_MODEL == 4)
> - Divisor = MmioRead32(BCM2836_CM_BASE + BCM2836_CM_VPU_CLOCK_DIVISOR) &
> 0xFFFFFF;
> - if (Divisor != 0)
> - BaseClockRate = (BaseClockRate << 12) / Divisor;
> -#endif
> + BaseClockRate = PcdGet32 (PcdSerialClockRate);
>
> //
> // As per the BCM2xxx datasheets:
> // baudrate = system_clock_freq / (8 * (divisor + 1)).
> //
> - Divisor = (UINT32)BaseClockRate / (SerialBaudRate * 8);
> + Divisor = BaseClockRate / (SerialBaudRate * 8);
> if (Divisor != 0) {
> Divisor--;
> }
> diff --git
> a/Platform/RaspberryPi/Library/PlatformLib/AArch64/RaspberryPiHelper.S
> b/Platform/RaspberryPi/Library/PlatformLib/AArch64/RaspberryPiHelper.S
> index 58351e4fb8cc..7008aaf8aa4c 100644
> --- a/Platform/RaspberryPi/Library/PlatformLib/AArch64/RaspberryPiHelper.S
> +++ b/Platform/RaspberryPi/Library/PlatformLib/AArch64/RaspberryPiHelper.S
> @@ -85,13 +85,11 @@ ASM_FUNC (ArmPlatformPeiBootAction)
> adr x2, mBoardRevision
> str w0, [x2]
>
> -#if (RPI_MODEL == 3)
> run .Lclkinfo_buffer
>
> ldr w0, .Lfrequency
> adr x2, _gPcd_BinaryPatch_PcdSerialClockRate
> str w0, [x2]
> -#endif
>
> ret
>
> @@ -135,7 +133,6 @@ ASM_FUNC (ArmPlatformPeiBootAction)
> .long 0 // end tag
> .set .Lrevinfo_size, . - .Lrevinfo_buffer
>
> -#if (RPI_MODEL == 3)
> .align 4
> .Lclkinfo_buffer:
> .long .Lclkinfo_size
> @@ -148,7 +145,6 @@ ASM_FUNC (ArmPlatformPeiBootAction)
> .long 0 // frequency
> .long 0 // end tag
> .set .Lclkinfo_size, . - .Lclkinfo_buffer
> -#endif
>
> //UINTN
> //ArmPlatformGetPrimaryCoreMpId (
> diff --git a/Platform/RaspberryPi/RPi4/RPi4.dsc
> b/Platform/RaspberryPi/RPi4/RPi4.dsc
> index 2c05c31118d2..ff802d8347ea 100644
> --- a/Platform/RaspberryPi/RPi4/RPi4.dsc
> +++ b/Platform/RaspberryPi/RPi4/RPi4.dsc
> @@ -429,7 +429,6 @@ [PcdsFixedAtBuild.common]
> gArmPlatformTokenSpaceGuid.PL011UartClkInHz|48000000
> gEfiMdeModulePkgTokenSpaceGuid.PcdSerialUseMmio|TRUE
> gEfiMdeModulePkgTokenSpaceGuid.PcdSerialRegisterStride|4
> - gEfiMdeModulePkgTokenSpaceGuid.PcdSerialClockRate|1000000000
> gEfiMdeModulePkgTokenSpaceGuid.PcdSerialFifoControl|0x27
> gEfiMdeModulePkgTokenSpaceGuid.PcdSerialExtendedTxFifoSize|8
> gEfiMdePkgTokenSpaceGuid.PcdUartDefaultBaudRate|115200
> @@ -465,6 +464,9 @@ [PcdsFixedAtBuild.common]
> gEfiMdeModulePkgTokenSpaceGuid.PcdFirmwareVendor|L"EDK2"
> gEfiMdeModulePkgTokenSpaceGuid.PcdSetNxForStack|TRUE
>
> +[PcdsPatchableInModule]
> + gEfiMdeModulePkgTokenSpaceGuid.PcdSerialClockRate|500000000
> +
> [PcdsDynamicHii.common.DEFAULT]
>
> #
> @@ -621,7 +623,7 @@ [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
> EmbeddedPkg/Drivers/ConsolePrefDxe/ConsolePrefDxe.inf
> --
> 2.29.2.windows.2
>
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