Then, this statement:
*(u32 *) (&tx_desc->ctrl.vlan_tag) |= ring->doorbell_qpn;
...
instead do ... :
*(u32 *) (&tx_desc->ctrl.vlan_tag) |=
cpu_to_be32(ring->doorbell_qpn);
(Also get rid of that cast and define vlan_tag as a __be32 to start
with).
Agreed, casts that change the type of memory - *(foo *)&xxx - are
generally bad news unless you are casting a generic 'buffer' to
a specific structure.
I've seen far to much code that ends up being depending on the
endianness and system word size.
For the above I'd actually suggest making 'doorbell_qpn' have the
correct endianness in order to avoid the (potential) swap every
time it is set.
You also need to treble-check the required endianness for the
'vlan_tag' in the tx descriptor. What would be needed is the
MAC PCI slave were on an x86 (LE) system.
David