SNP_INIT while in TPL_NOTIFY

["Tomas Pilar (tpilar)" <tpilar@solarflare.com>]

Hi,

I am currently maintaining our network driver written using the EDKII
framework. Our network device implements a MCDI (mc-driver interface)
which is (in theory) asynchronous (DMA doorbell-messagebox
communication), although the majority of the calls take less than a
jiffy. So for example, the setting up of TX and RX queues on the NIC
requires some MCDI calls which the driver then has to wait for. I've
implemented this using the gSB->SetTimer event system.

My problem is that the SimpleNetworkInitialize() method is called by the
UEFI platform network core (network core finds a new NIC with SNP ->
tries to open -> not initialised, so it tries to INIT) using a
TPL_NOTIFY context, where the code is not allowed to sleep (I assume
that this is the MNP generic one second network poll timer). I could in
theory initialise the NIC earlier, during probe, but the SNP allows for
specification of extra buffer space for TX and RX during init. The
network core might conceivable use that. Or the MNP might want to change
station address using SNP or call for a reset which again requires
asynchronous NIC operation.

Has anyone encountered something similar? Is there a canonical solution
to this issue?

Cheers,
Tomas Pilar


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