[edk2-devel] [edk2-platforms][PATCH 1/1] Platform/RaspberryPi: Fix mini UART baud divisor calculation

[Mario Bălănică]

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 <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

-- 
2.29.2.windows.2



-=-=-=-=-=-=-=-=-=-=-=-
Groups.io Links: You receive all messages sent to this group.
View/Reply Online (#73659): https://edk2.groups.io/g/devel/message/73659
Mute This Topic: https://groups.io/mt/81808942/1813853
Group Owner: devel+owner at edk2.groups.io
Unsubscribe: https://edk2.groups.io/g/devel/unsub [edk2-devel-archive at redhat.com]
-=-=-=-=-=-=-=-=-=-=-=-