Introduce three new DebugLib instances, forked from
MdePkg/Library/BaseDebugLibSerialPort. All three instances rely on
PL011UartLib rather than SerialPortLib so that they can customize the
PL011 UART that the debug messages are written to. All three instances
direct the debug output to the first such PL011 UART that *differs* from
the one specified in the Device Tree's /chosen node's "stdout-path"
property.
From these, DebugLibFdtPL011UartFlash mirrors EarlyFdtPL011SerialPortLib:
it parses the initial Device Tree, and initializes the UART -- a UART
different from EarlyFdtPL011SerialPortLib's -- for every message written.
Suitable for SEC, PEI_CORE, PEIM.
(Note that OVMF uses a similar set of dedicated DebugLib instances
(PlatformDebugLibIoPort) for logging to the (x86-only) isa-debugcon device
from various firmware phases.)
The contexts in which these DebugLib instances run are identical to those
in which the corresponding SerialPortLib instances run. The particular
original dependency chain is
BaseDebugLibSerialPort (SEC, PEI_CORE, PEIM)
EarlyFdtPL011SerialPortLib
PcdDeviceTreeInitialBaseAddress
FdtSerialPortAddressLib
PL011UartLib
and the new dependency chain is
DebugLibFdtPL011UartFlash (SEC, PEI_CORE, PEIM)
PcdDeviceTreeInitialBaseAddress
FdtSerialPortAddressLib
PL011UartLib
Note that EarlyFdtPL011SerialPortLib remains in use (just not via
BaseDebugLibSerialPort), namely for direct SerialPortLib calls from SEC,
PEI_CORE, PEIM. See for example commit 56035d1c8b
("ArmPlatformPkg/PrePeiCore: Print the firmware version early in boot",
2022-10-25).
The ArmVirtPkg DSC files will be switched to the new library instances in
a separate patch.
This patch is worth viewing with "git show --find-copies-harder".
Cc: Ard Biesheuvel <ardb+tianocore@kernel.org>
Cc: Gerd Hoffmann <kraxel@redhat.com>
Cc: Leif Lindholm <quic_llindhol@quicinc.com>
Cc: Sami Mujawar <sami.mujawar@arm.com>
Signed-off-by: Laszlo Ersek <lersek@redhat.com>
Message-Id: <20231008153912.175941-7-lersek@redhat.com>
Acked-by: Ard Biesheuvel <ardb@kernel.org>
Ref: https://bugzilla.tianocore.org/show_bug.cgi?id=4577
[lersek@redhat.com: add TianoCore BZ reference]
Laszlo Ersek