Add module option db_fc_threshold which is the count of active QPs
that trigger automatic db flow control mode.  Automatically transition
to/from flow control mode when the active qp count crosses
db_fc_theshold.

Add more db debugfs stats

On DB DROP event from the LLD, recover all the iwarp queues.
Signed-off-by: NVipul Pandya <vipul@chelsio.com>
Signed-off-by: NSteve Wise <swise@opengridcomputing.com>
Signed-off-by: NRoland Dreier <roland@purestorage.com>

Get FULL/EMPTY/DROP events from LLD.  On FULL event, disable normal
user mode DB rings.

Add modify_qp semantics to allow user processes to call into the
kernel to ring doobells without overflowing.

Add DB Full/Empty/Drop stats.

Mark queues when created indicating the doorbell state.

If we're in the middle of db overflow avoidance, then newly created
queues should start out in this mode.

Bump the C4IW_UVERBS_ABI_VERSION to 2 so the user mode library can
know if the driver supports the kernel mode db ringing.
Signed-off-by: NVipul Pandya <vipul@chelsio.com>
Signed-off-by: NSteve Wise <swise@opengridcomputing.com>
Signed-off-by: NRoland Dreier <roland@purestorage.com>

Signed-off-by: NVipul Pandya <vipul@chelsio.com>
Signed-off-by: NSteve Wise <swise@opengridcomputing.com>
Signed-off-by: NRoland Dreier <roland@purestorage.com>

The iw_cxgb4 module crashes at init time if the T4 card does not
support RDMA.  So clean up the init logic to correctly deal with
non-RDMA cards.

 - If any RDMA resources are not available, then fail the initialization
   logging an info message.
 - Clean up properly on initialization failures.
Signed-off-by: NSteve Wise <swise@opengridcomputing.com>
Signed-off-by: NRoland Dreier <roland@purestorage.com>

A few more EEH fixes:

c4iw_wait_for_reply(): detect fatal EEH condition on timeout and
return an error.

The iw_cxgb4 driver was only calling ib_deregister_device() on an EEH
event followed by a ib_register_device() when the device was
reinitialized.  However, the RDMA core doesn't allow multiple
iterations of register/deregister by the provider. See
drivers/infiniband/core/sysfs.c: ib_device_unregister_sysfs() where
the kobject ref is held until the device is deallocated in
ib_deallocate_device().  Calling deregister adds this kobj reference,
and then a subsequent register call will generate a WARN_ON() from the
kobject subsystem because the kobject is being initialized but is
already initialized with the ref held.

So the provider must deregister and dealloc when resetting for an EEH
event, then alloc/register to re-initialize.  To do this, we cannot
use the device ptr as our ULD handle since it will change with each
reallocation.  This commit adds a ULD context struct which is used as
the ULD handle, and then contains the device pointer and other state
needed.
Signed-off-by: NSteve Wise <swise@opengridcomputing.com>
Signed-off-by: NRoland Dreier <roland@purestorage.com>

c4iw_uld_add() must return ERR_PTR() values instead of NULL on failure.
Signed-off-by: NSteve Wise <swise@opengridcomputing.com>
Signed-off-by: NRoland Dreier <roland@purestorage.com>

- Show whether the SQ is in onchip memory or not.
- Dump both SQ and RQ QIDs.
Signed-off-by: NSteve Wise <swise@opengridcomputing.com>
Signed-off-by: NRoland Dreier <roland@purestorage.com>

This at least kicks the user mode applications that are watching for
device events.
Signed-off-by: NSteve Wise <swise@opengridcomputing.com>
Signed-off-by: NRoland Dreier <roland@purestorage.com>

Unloading iw_cxgb4 can crash due to the unload code trying to use
db_drop_task, which is uninitialized.  So remove this dead code.
Signed-off-by: NSteve Wise <swise@opengridcomputing.com>
Signed-off-by: NRoland Dreier <roland@purestorage.com>

Remove the local service t4_pktgl_to_skb() and use cxgb4_pktgl_to_skb()
exported by cxgb4.
Signed-off-by: NSteve Wise <swise@opengridcomputing.com>
Signed-off-by: NRoland Dreier <rolandd@cisco.com>

We can replace our equivalent open-coded version.
Signed-off-by: NSteve Wise <swise@opengridcomputing.com>
Signed-off-by: NRoland Dreier <rolandd@cisco.com>

Incorporate BKL removal changes.
Signed-off-by: NSteve Wise <swise@opengridcomputing.com>
Signed-off-by: NRoland Dreier <rolandd@cisco.com>

T4 support on-chip SQs to reduce latency.  This patch adds support for
this in iw_cxgb4:

 - Manage ocqp memory like other adapter mem resources.
 - Allocate user mode SQs from ocqp mem if available.
 - Map ocqp mem to user process using write combining.
 - Map PCIE_MA_SYNC reg to user process.

Bump uverbs ABI.
Signed-off-by: NSteve Wise <swise@opengridcomputing.com>
Signed-off-by: NRoland Dreier <rolandd@cisco.com>

Add "stags" debugfs file.  This is useful for examining the TPTE and
PBL entries in adapter memory.  It allows scripts to dump just the
active entries.

Also clean up the "qps" file handlers and shared common code.
Signed-off-by: NSteve Wise <swise@opengridcomputing.com>
Signed-off-by: NRoland Dreier <rolandd@cisco.com>

Signed-off-by: NSteve Wise <swise@opengridcomputing.com>
Signed-off-by: NRoland Dreier <rolandd@cisco.com>

The LLD now supports proper UP state change events, so move the RDMA
provider registration to UP path.

This fixes a crash when loading iw_cxgb4 _after_ the NFS/RDMA
transport is up and running.
Signed-off-by: NSteve Wise <swise@opengridcomputing.com>
Signed-off-by: NRoland Dreier <rolandd@cisco.com>

In the RDMA core unregister path, kernel users will be calling down
into the T4 provider to release resources.  So we cannot detach from
the LLD until this process completes.
Signed-off-by: NSteve Wise <swise@opengridcomputing.com>
Signed-off-by: NRoland Dreier <rolandd@cisco.com>

Add an RDMA/iWARP driver for Chelsio T4 Ethernet adapters.
Signed-off-by: NSteve Wise <swise@opengridcomputing.com>
Signed-off-by: NRoland Dreier <rolandd@cisco.com>