The physical function defaults to operating in "PXE mode" after a
power-on reset. In this mode, receive descriptors are fetched and
written back as single descriptors. In normal (non-PXE mode)
operation, receive descriptors are fetched and written back only as
complete cachelines unless an interrupt is raised.
There is no way to return to PXE mode from non-PXE mode, and there is
no way for the virtual function driver to operate in PXE mode.
Choose to operate in non-PXE mode. This requires us to trick the
hardware into believing that it is raising an interrupt, so that it
will not defer writing back receive descriptors until a complete
cacheline (i.e. four packets) have been consumed. We do so by
configuring the hardware to use MSI-X with a dummy target location in
place of the usual APIC register.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
[intelxl] Split out ring creation from context programming
The virtual function driver will use the same transmit and receive
descriptor ring structures, but will not itself construct and program
the ring context. Split out ring creation and destruction from the
programming of the ring context, to allow code to be shared between
physical and virtual function drivers.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
[intelxl] Allow for arbitrary placement of ring tail registers
The virtual function transmit and receive ring tail register offsets
do not match those of the physical function. Allow the tail register
offsets to be specified separately.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
The physical function driver does not allow the virtual function to
request the use of 16-byte receive descriptors. Switch to using
32-byte receive descriptors.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
[intelxl] Provide a mechanism for handling "send to VF" events
Provide a weak stub function for handling the "send to VF" event used
for communications between the physical and virtual function drivers.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
[intelxl] Allow admin cookie to hold extended opcode and return code
The "send to PF" and "send to VF" admin queue descriptors (ab)use the
cookie field to hold the extended opcode and return code values.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
A virtual function reset is triggered via an admin queue command and
will reset the admin queue configuration registers. Allow the admin
queues to be reinitialised after such a reset, without requiring the
overhead (and potential failure paths) of freeing and reallocating the
queues.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
[intelxl] Use one admin queue buffer per admin queue descriptor
We currently use a single data buffer shared between all admin queue
descriptors. This works for the physical function driver since we
have at most one command in progress and only a single event (which
does not use a data buffer).
The communication path between the physical and virtual function
drivers uses the event data buffer, and there is no way to prevent a
solicited event (i.e. a response to a request) from being overwritten
by an unsolicited event (e.g. a link status change).
Provide individual data buffers for each admin event queue descriptor
(and for each admin command queue descriptor, for the sake of
consistency).
Signed-off-by: Michael Brown <mcb30@ipxe.org>
[intelxl] Allow for virtual function admin queue register maps
The register map for the virtual functions appears to have been
constructed using a random number generator.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
[intelxl] Use VLAN tag in receive descriptor if present
The physical function driver does not allow the virtual function to
request that VLAN tags are left unstripped. Extract and use the VLAN
tag from the receive descriptor if present.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Michael Brown