Commit Graph

3 Commits

Author SHA1 Message Date
Laszlo Ersek 601abf5d50 ArmVirtPkg: introduce DebugLibFdtPL011Uart DXE Runtime instance
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, DxeRuntimeDebugLibFdtPL011Uart is identical to
DebugLibFdtPL011UartRam, with the addition that UART access is permanently
disabled when the containing DXE_RUNTIME_DRIVER module is notified about
exiting boot services.

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

  DxeRuntimeDebugLibSerialPort (DXE_RUNTIME_DRIVER)
    FdtPL011SerialPortLib
      gEarlyPL011BaseAddressGuid
      HobLib
      PL011UartLib

and the new dependency chain is

  DxeRuntimeDebugLibFdtPL011Uart (DXE_RUNTIME_DRIVER)
    gEarlyPL011BaseAddressGuid
    HobLib
    PL011UartLib

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: <20231008153912.175941-9-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]
2023-10-26 18:55:43 +00:00
Laszlo Ersek ba5d955e25 ArmVirtPkg: introduce DebugLibFdtPL011Uart RAM instance
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, DebugLibFdtPL011UartRam mirrors FdtPL011SerialPortLib: it
relies on the EarlyPL011BaseAddress GUID HOB, and initializes the UART --
a UART different from FdtPL011SerialPortLib's -- only once in the lifetime
of the containing module. Suitable for module types that can only execute
from RAM (i.e., all types different from SEC, PEI_CORE, PEIM), except
DXE_RUNTIME_DRIVER.

(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 (not SEC, PEI_CORE, PEIM, DXE_RUNTIME_DRIVER)
    FdtPL011SerialPortLib
      gEarlyPL011BaseAddressGuid
      HobLib
      PL011UartLib

and the new dependency chain is

  DebugLibFdtPL011UartRam (not SEC, PEI_CORE, PEIM, DXE_RUNTIME_DRIVER)
    gEarlyPL011BaseAddressGuid
    HobLib
    PL011UartLib

Note that FdtPL011SerialPortLib remains in use (just not via
BaseDebugLibSerialPort); for instance by MdeModulePkg/Universal/SerialDxe,
which produces the SerialIo protocol, underlying the UEFI console.

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: <20231008153912.175941-8-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]
2023-10-26 18:55:43 +00:00
Laszlo Ersek b7e6d97973 ArmVirtPkg: introduce DebugLibFdtPL011Uart Flash instance
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]
2023-10-26 18:55:43 +00:00