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

["Ard Biesheuvel" <ard.biesheuvel@arm.com>]

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;
+}
-- 
2.17.1