Re: [PATCH] Platform/FVP-AArch64: use different serial ports for DEBUG and console

[Ard Biesheuvel <ard.biesheuvel@linaro.org>]

On Thu, 20 Dec 2018 at 16:20, Leif Lindholm <leif.lindholm@linaro.org> wrote:
>
> On Mon, Dec 17, 2018 at 07:53:53PM +0100, Ard Biesheuvel wrote:
> > The FVP models expose several emulated serial ports, and always start with
> > Xterm windows connected to at least two of them. So let's switch to the
> > second one for DEBUG output, leaving the original one for console output
> > via SerialDxe.
>
> Could you clarify whether this means _all_ non-DEBUG output will go to
> the first UART, or whether there is a switchover point and some early
> non-DEBUG messages will now appear on the second UART?
>

Ah yes, good point.

So any explicit calls to SerialPorWrite () from modules other than
SerialDxe will get directed to the second UART in this case.

There is such a call in PrePi:

CharCount = AsciiSPrint (Buffer,sizeof (Buffer),
    "UEFI firmware (version %s built at %a on %a)\n\r",
    (CHAR16*)PcdGetPtr(PcdFirmwareVersionString), __TIME__, __DATE__);
SerialPortWrite ((UINT8 *) Buffer, CharCount)

and in one or two other places. Also note that DEBUG() directives in
SerialDxe itself will be sent to the non-DEBUG uart.

I think it makes sense for the DefaultExceptionHandlerLib to write to
the console instead of doing a SerialPortWrite () on RELEASE builds,
so I'll look into that next.


> With that:
> Reviewed-by: Leif Lindholm <leif.lindholm@linaro.org>
>
> > Contributed-under: TianoCore Contribution Agreement 1.1
> > Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
> > ---
> >  Platform/ARM/VExpressPkg/ArmVExpress-FVP-AArch64.dsc | 7 +++++--
> >  1 file changed, 5 insertions(+), 2 deletions(-)
> >
> > diff --git a/Platform/ARM/VExpressPkg/ArmVExpress-FVP-AArch64.dsc b/Platform/ARM/VExpressPkg/ArmVExpress-FVP-AArch64.dsc
> > index 7094e57ee13a..7db1c675c3d9 100644
> > --- a/Platform/ARM/VExpressPkg/ArmVExpress-FVP-AArch64.dsc
> > +++ b/Platform/ARM/VExpressPkg/ArmVExpress-FVP-AArch64.dsc
> > @@ -125,7 +125,7 @@
>
> .inf diff format would have been slightly nicer here.
>
> >    gArmPlatformTokenSpaceGuid.PcdSP805WatchdogClockFrequencyInHz|24000000
> >
> >    ## PL011 - Serial Terminal
> > -  gEfiMdeModulePkgTokenSpaceGuid.PcdSerialRegisterBase|0x1c090000
> > +  gEfiMdeModulePkgTokenSpaceGuid.PcdSerialRegisterBase|0x1c0a0000
> >    gEfiMdePkgTokenSpaceGuid.PcdUartDefaultBaudRate|115200
> >    gEfiMdePkgTokenSpaceGuid.PcdUartDefaultReceiveFifoDepth|0
> >
> > @@ -239,7 +239,10 @@
> >    MdeModulePkg/Universal/Console/ConSplitterDxe/ConSplitterDxe.inf
> >    MdeModulePkg/Universal/Console/GraphicsConsoleDxe/GraphicsConsoleDxe.inf
> >    MdeModulePkg/Universal/Console/TerminalDxe/TerminalDxe.inf
> > -  MdeModulePkg/Universal/SerialDxe/SerialDxe.inf
> > +  MdeModulePkg/Universal/SerialDxe/SerialDxe.inf {
> > +    <PcdsFixedAtBuild>
> > +      gEfiMdeModulePkgTokenSpaceGuid.PcdSerialRegisterBase|0x1c090000
> > +  }
> >
> >    MdeModulePkg/Universal/HiiDatabaseDxe/HiiDatabaseDxe.inf
> >
> > --
> > 2.17.1
> >