scsi: lpfc: Fix panic on BFS configuration

scsi: lpfc: Fix panic on BFS configuration

To select the appropriate shost template, the driver is issuing a
mailbox command to retrieve the wwn. Turns out the sending of the
command precedes the reset of the function.  On SLI-4 adapters, this is
inconsequential as the mailbox command location is specified by dma via
the BMBX register. However, on SLI-3 adapters, the location of the
mailbox command submission area changes. When the function is first
powered on or reset, the cmd is submitted via PCI bar memory. Later the
driver changes the function config to use host memory and DMA. The
request to start a mailbox command is the same, a simple doorbell write,
regardless of submission area.  So.. if there has not been a boot driver
run against the adapter, the mailbox command works as defaults are
ok. But, if the boot driver has configured the card and, and if no
platform pci function/slot reset occurs as the os starts, the mailbox
command will fail. The SLI-3 device will use the stale boot driver dma
location. This can cause PCI eeh errors.

Fix is to reset the sli-3 function before sending the mailbox command,
thus synchronizing the function/driver on mailbox location.

Note: The fix uses routines that are typically invoked later in the call
flow to reset the sli-3 device. The issue in using those routines is
that the normal (non-fix) flow does additional initialization, namely
the allocation of the pport structure. So, rather than significantly
reworking the initialization flow so that the pport is alloc'd first,
pointer checks are added to work around it. Checks are limited to the
routines invoked by a sli-3 adapter (s3 routines) as this fix/early call
is only invoked on a sli3 adapter. Nothing changes post the
fix. Subsequent initialization, and another adapter reset, still occur -
both on sli-3 and sli-4 adapters.

Signed-off-by: Dick Kennedy <dick.kennedy@broadcom.com>
Signed-off-by: James Smart <james.smart@broadcom.com>
Fixes: 96418b5e2c88 ("scsi: lpfc: Fix eh_deadline setting for sli3 adapters.")
Cc: stable@vger.kernel.org # v4.11+
Reviewed-by: Ewan D. Milne <emilne@redhat.com>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>