It is the responsibility of the SerialPortLib implementation
to deal with flow control if the underlying medium cannot keep
up with the inflow of data.
So in our SerialPortWrite () function, we should spin as long
as we need to in order to deliver all the data instead of giving
up and returning a smaller value than the number of bytes we were
given. Also, remove the 'if (Sent > 0)' condition on the signalling
of the event channel: if the buffer is full and we haven't been able
to add any more data, it makes perfect sense to signal the event
channel again, even if we have done so before when we did write
the data.
Also, this patch brings the implementation of XenSerialPortLib
in sync with the library class documentation.
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Reviewed-by: Laszlo Ersek <lersek@redhat.com>
[lersek@redhat.com: replace DebugLib dependency with open-coded ASSERT()]
git-svn-id: https://svn.code.sf.net/p/edk2/code/trunk/edk2@17079 6f19259b-4bc3-4df7-8a09-765794883524
XenHypercallLib has two clients at the moment: XenBusDxe and
XenConsoleSerialPortLib. Currently, when XenBusDxe starts on a non-Xen X86
platform (ie. as part of OVMF not running on Xen), the X86XenHypercallLib
instance built into it fails to initialize, which triggers an ASSERT() in
auto-generated code.
Instead, let's call XenHypercallIsAvailable() in the driver's entry point,
and exit cleanly when the driver is started on a non-Xen platform.
Modify the constructor of XenConsoleSerialPortLib similarly; we shouldn't
proceed if Xen is not available. In practice this check should never fail,
because XenConsoleSerialPortLib is only used on ARM, and
ArmXenHypercallLib is always available; but nonetheless we should be
pedantic.
Reported-by: Gabriel L. Somlo <gsomlo@gmail.com>
Suggested-by: Jordan Justen <jordan.l.justen@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Jordan Justen <jordan.l.justen@intel.com>
Reviewed-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Tested-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
git-svn-id: https://svn.code.sf.net/p/edk2/code/trunk/edk2@17001 6f19259b-4bc3-4df7-8a09-765794883524
This implements a SerialPortLib instance that wires up to the
PV console ring used by domU guests. Also imports the required
upstream Xen io/console.h header.
Contributed-under: TianoCore Contribution Agreement 1.0
Reviewed-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Acked-by: Laszlo Ersek <lersek@redhat.com>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Laszlo Ersek <lersek@redhat.com>
git-svn-id: https://svn.code.sf.net/p/edk2/code/trunk/edk2@16976 6f19259b-4bc3-4df7-8a09-765794883524
Star Zeng
Ard Biesheuvel
Laszlo Ersek