Upcoming firmware introduces command interface revision 3, which
changes the way port capabilities are queried and set.  Update the
driver to handle both the new and old command interfaces by adding a
new MLX4_FLAG_OLD_PORT_CMDS that it is set after querying the firmware
interface revision and then using the correct interface based on the
setting of the flag.
Signed-off-by: NRoland Dreier <rolandd@cisco.com>

We may call mlx4_dispatch_event() before mlx4_register_device() is
called for a device, because for example a catastrophic error happens
immediately after we enable interrupts.  Therefore priv->ctx_list and
priv->ctx_lock need to be initialized earlier.

This bug was actually exposed by the MSI-X bug that returned IRQ numbers 
to drivers in reverse order, so that the first FW command 
interrupt looked to mlx4 like a catastrophic error.
Signed-off-by: NRoland Dreier <rolandd@cisco.com>

struct mlx4_priv.doorbell_lock is never used, so delete it.
Signed-off-by: NRoland Dreier <rolandd@cisco.com>

Add an InfiniBand driver for Mellanox ConnectX adapters.  Because
these adapters can also be used as ethernet NICs and Fibre Channel 
HBAs, the driver is split into two modules: 
 
  mlx4_core: Handles low-level things like device initialization and 
    processing firmware commands.  Also controls resource allocation 
    so that the InfiniBand, ethernet and FC functions can share a 
    device without stepping on each other. 
 
  mlx4_ib: Handles InfiniBand-specific things; plugs into the 
    InfiniBand midlayer. 
Signed-off-by: NRoland Dreier <rolandd@cisco.com>