[edk2-devel] [edk2-platforms][PATCH v2 1/1] Platform/RaspberryPi: Fix mini UART clock divisor calculation
Pete Batard
pete at akeo.ie
Thu Apr 8 11:43:34 UTC 2021
On 2021.04.08 12:06, Ard Biesheuvel wrote:
> On Thu, 8 Apr 2021 at 11:47, Pete Batard <pete at akeo.ie> wrote:
>>
>> On 2021.04.06 15:04, Mario Bălănică wrote:
>>> The VPU clock divisor has changed in this commit:
>>> https://github.com/raspberrypi/firmware/commit/1e5456a,
>>> thus breaking the mini UART clock divisor calculation on the Pi 4.
>>>
>>> Fix this by reading the core clock from the mailbox instead.
>>>
>>> Signed-off-by: Mario Bălănică <mariobalanica02 at gmail.com>
>>> ---
>>> 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
>>>
>>
>> Reviewed-by: Pete Batard <pete at akeo.ie>
>> Tested-by: Pete Batard <pete at akeo.ie>
>
> Thanks Pete.
>
> Could anyone get me a version of this patch that is not whitespace
> mangled? This one does not apply with 'git am'
>
Done.
The version I sent is the one I applied & tested after I ran it through
my unmangling script to remove the extra lines.
Not sure if it'll still not be re-mangled by the list processing though.
Regards,
/Pete
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