sfc: Workaround flush failures on Falcon B0

Under certain conditions a PHY may backpressure Falcon B0
in such a way that flushes timeout. In normal circumstances
the phy poller would fix the PHY, and the flush could complete.

But efx_nic_flush_queues() is always called after efx_stop_all(),
so the poller has been stopped. Even if this weren't the case,
how long would we have to wait for the poller to fix this? And
several callers of efx_nic_flush_queues() are about to reset
the device anyway - so we don't need to do anything.

Work around this bug by scheduling a reset. Ensure that the
MAC is never rewired back into the datapath before the reset
runs (we already ignore all rx events anyway).

Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 0 insertions, 3 deletions

diff --git a/drivers/net/sfc/nic.c b/drivers/net/sfc/nic.c
index 5d3aaec58556..ec0bb80f5ae8 100644
--- a/drivers/net/sfc/nic.c
+++ b/drivers/net/sfc/nic.c
@@ -1219,9 +1219,6 @@ int efx_nic_flush_queues(struct efx_nic *efx)
                 rx_queue->flushed = FLUSH_DONE;
         }
 
-        if (EFX_WORKAROUND_7803(efx))
-                return 0;
-
         return -ETIMEDOUT;
 }