sfc:On MCDI timeout, issue an FLR (and mark MCDI to fail-fast)

When an MCDI command times out (whether or not we find it
completed when we poll), call efx_mcdi_abandon(), which tells
all subsequent MCDI calls to fail-fast, and queues up an FLR.

Because an FLR doesn't lead to receiving any reboot even from
the MC (unlike most other types of reset), we have to call
efx_ef10_reset_mc_allocations.
In efx_start_all(), if a reset (of any kind) is pending, we
bail out.
Without this, attempts to reconfigure (e.g. change mtu) can
cause driver/mc state inconsistency if the first MCDI call
triggers an FLR.

For similar reasons, on EF10, in
efx_reset_down(method=RESET_TYPE_MCDI_TIMEOUT), set the number
of active queues to zero before calling efx_stop_all().
And, on farch, in efx_reset_up(method=RESET_TYPE_MCDI_TIMEOUT),
set active_queues and flushes pending & outstanding to zero.

efx_mcdi_mode_{poll,event}() should not take us out of fail-fast
 mode. Instead, this is done by efx_mcdi_reset() after the FLR
completes.

The new FLR reset_type RESET_TYPE_MCDI_TIMEOUT doesn't really
fit into the hierarchy of reset 'scopes' whereby efx_reset()
decides some resets subsume others.  Thus, it uses separate logic.

Also, fixed up some inconsistency around RESET_TYPE_MC_BIST,
which was in the wrong place in that hierarchy.

Signed-off-by: Shradha Shah <sshah@solarflare.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 11 insertions, 1 deletions

diff --git a/drivers/net/ethernet/sfc/ef10.c b/drivers/net/ethernet/sfc/ef10.c
index 21c20ea0dad0..b5ed30a39144 100644
--- a/drivers/net/ethernet/sfc/ef10.c
+++ b/drivers/net/ethernet/sfc/ef10.c
@@ -738,8 +738,11 @@ static int efx_ef10_reset(struct efx_nic *efx, enum reset_type reset_type)
 	/* If it was a port reset, trigger reallocation of MC resources.
 	 * Note that on an MC reset nothing needs to be done now because we'll
 	 * detect the MC reset later and handle it then.
+	 * For an FLR, we never get an MC reset event, but the MC has reset all
+	 * resources assigned to us, so we have to trigger reallocation now.
 	 */
-	if (reset_type == RESET_TYPE_ALL && !rc)
+	if ((reset_type == RESET_TYPE_ALL ||
+	     reset_type == RESET_TYPE_MCDI_TIMEOUT) && !rc)
 		efx_ef10_reset_mc_allocations(efx);
 	return rc;
 }
@@ -2141,6 +2144,11 @@ static int efx_ef10_fini_dmaq(struct efx_nic *efx)
 	return 0;
 }
 
+static void efx_ef10_prepare_flr(struct efx_nic *efx)
+{
+	atomic_set(&efx->active_queues, 0);
+}
+
 static bool efx_ef10_filter_equal(const struct efx_filter_spec *left,
 				  const struct efx_filter_spec *right)
 {
@@ -3603,6 +3611,8 @@ const struct efx_nic_type efx_hunt_a0_nic_type = {
 	.probe_port = efx_mcdi_port_probe,
 	.remove_port = efx_mcdi_port_remove,
 	.fini_dmaq = efx_ef10_fini_dmaq,
+	.prepare_flr = efx_ef10_prepare_flr,
+	.finish_flr = efx_port_dummy_op_void,
 	.describe_stats = efx_ef10_describe_stats,
 	.update_stats = efx_ef10_update_stats,
 	.start_stats = efx_mcdi_mac_start_stats,