audk/ArmVirtPkg/Library/Fdt16550SerialPortHookLib
Sami Mujawar a482f08d99 ArmVirtPkg: 16550 UART Platform hook library
The BaseSerialPort16550 library invokes the
PlatformHookSerialPortInitialize() implemented as
part of the PlatformHook library, to perform platform
specific initialization required to enable use of the
16550 device. The BaseSerialPort16550 library uses
the PcdSerialRegisterBase to obtain the base address
of the UART for MMIO operations.

Some VMMs like Kvmtool provide the base address of
the console serial port in the platform device tree.

This patch introduces two instances of the Platform
Hook library:
1. EarlyFdt16550SerialPortHookLib - parses the
   platform device tree to extract the base
   address of the 16550 UART and update the PCD
   PcdSerialRegisterBase.
2. Fdt16550SerialPortHookLib - reads the GUID
   Hob gEarly16550UartBaseAddressGuid (that caches
   the base address of the 16550 UART discovered
   during early stages) and updates the PCD
   PcdSerialRegisterBase.

Note:
  a. The PCD PcdSerialRegisterBase is configured
     as PatchableInModule.
  b. A separate patch introduces a PlatformPeiLib
     that trampolines the 16550 UART base address
     from the Pcd PcdSerialRegisterBase to the
     GUID Hob gEarly16550UartBaseAddressGuid.

Signed-off-by: Sami Mujawar <sami.mujawar@arm.com>
Reviewed-by: Ard Biesheuvel <Ard.Biesheuvel@arm.com>
Acked-by: Laszlo Ersek <lersek@redhat.com>
2020-10-16 17:21:04 +00:00
..
EarlyFdt16550SerialPortHookLib.c
EarlyFdt16550SerialPortHookLib.inf
Fdt16550SerialPortHookLib.c
Fdt16550SerialPortHookLib.inf
Fdt16550SerialPortHookLib.uni