sfc: Simplify XMAC link polling

From: Steve Hodgson <shodgson@solarflare.com>

Only the XMAC on Falcon needs help from the driver to poll and reset
the MAC-PHY link (XAUI); GMII is a simple parallel bus and on later
NICs firmware takes care of the XAUI link.  Also, an XMAC interrupt
currently schedules a work item which simply clears a flag
(efx_nic::mac_up) to be checked by the regular monitor (or the next
link reconfiguration, if that is sooner).

Rename the flag to xmac_poll_required, changing its sense.  Remove the
needless indirection and just set the flag immediately.  Call
falcon_xmac_poll() directly where required.

Add a new generic operation mac_op::check_fault to check the link
outside of regular monitoring, as required during self-tests.

(Note that this leaves us with an unused work item, but we will
immediately have another use for it.)

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

1 files changed, 20 insertions, 30 deletions

diff --git a/drivers/net/sfc/falcon_xmac.c b/drivers/net/sfc/falcon_xmac.c
index e57545de60ff..784260f63d4c 100644
--- a/drivers/net/sfc/falcon_xmac.c
+++ b/drivers/net/sfc/falcon_xmac.c
@@ -98,7 +98,7 @@ static void falcon_mask_status_intr(struct efx_nic *efx, bool enable)
 
 	/* We can only use this interrupt to signal the negative edge of
 	 * xaui_align [we have to poll the positive edge]. */
-	if (!efx->mac_up)
+	if (efx->xmac_poll_required)
 		return;
 
 	/* Flush the ISR */
@@ -243,29 +243,35 @@ static void falcon_reconfigure_xgxs_core(struct efx_nic *efx)
 }
 
 
-/* Try and bring the Falcon side of the Falcon-Phy XAUI link fails
- * to come back up. Bash it until it comes back up */
-static void falcon_check_xaui_link_up(struct efx_nic *efx, int tries)
+/* Try to bring up the Falcon side of the Falcon-Phy XAUI link */
+static bool falcon_check_xaui_link_up(struct efx_nic *efx, int tries)
 {
-	efx->mac_up = falcon_xaui_link_ok(efx);
+	bool mac_up = falcon_xaui_link_ok(efx);
 
 	if ((efx->loopback_mode == LOOPBACK_NETWORK) ||
 	    efx_phy_mode_disabled(efx->phy_mode))
 		/* XAUI link is expected to be down */
-		return;
+		return mac_up;
 
 	falcon_stop_nic_stats(efx);
 
-	while (!efx->mac_up && tries) {
+	while (!mac_up && tries) {
 		EFX_LOG(efx, "bashing xaui\n");
 		falcon_reset_xaui(efx);
 		udelay(200);
 
-		efx->mac_up = falcon_xaui_link_ok(efx);
+		mac_up = falcon_xaui_link_ok(efx);
 		--tries;
 	}
 
 	falcon_start_nic_stats(efx);
+
+	return mac_up;
+}
+
+static bool falcon_xmac_check_fault(struct efx_nic *efx)
+{
+	return !falcon_check_xaui_link_up(efx, 5);
 }
 
 static void falcon_reconfigure_xmac(struct efx_nic *efx)
@@ -277,7 +283,7 @@ static void falcon_reconfigure_xmac(struct efx_nic *efx)
 
 	falcon_reconfigure_mac_wrapper(efx);
 
-	falcon_check_xaui_link_up(efx, 5);
+	efx->xmac_poll_required = !falcon_check_xaui_link_up(efx, 5);
 	falcon_mask_status_intr(efx, true);
 }
 
@@ -341,35 +347,19 @@ static void falcon_update_stats_xmac(struct efx_nic *efx)
 		 mac_stats->rx_control * 64);
 }
 
-static void falcon_xmac_irq(struct efx_nic *efx)
-{
-	/* The XGMII link has a transient fault, which indicates either:
-	 *   - there's a transient xgmii fault
-	 *   - falcon's end of the xaui link may need a kick
-	 *   - the wire-side link may have gone down, but the lasi/poll()
-	 *     hasn't noticed yet.
-	 *
-	 * We only want to even bother polling XAUI if we're confident it's
-	 * not (1) or (3). In both cases, the only reliable way to spot this
-	 * is to wait a bit. We do this here by forcing the mac link state
-	 * to down, and waiting for the mac poll to come round and check
-	 */
-	efx->mac_up = false;
-}
-
-static void falcon_poll_xmac(struct efx_nic *efx)
+void falcon_poll_xmac(struct efx_nic *efx)
 {
-	if (!EFX_WORKAROUND_5147(efx) || !efx->link_state.up || efx->mac_up)
+	if (!EFX_WORKAROUND_5147(efx) || !efx->link_state.up ||
+	    !efx->xmac_poll_required)
 		return;
 
 	falcon_mask_status_intr(efx, false);
-	falcon_check_xaui_link_up(efx, 1);
+	efx->xmac_poll_required = !falcon_check_xaui_link_up(efx, 1);
 	falcon_mask_status_intr(efx, true);
 }
 
 struct efx_mac_operations falcon_xmac_operations = {
 	.reconfigure	= falcon_reconfigure_xmac,
 	.update_stats	= falcon_update_stats_xmac,
-	.irq		= falcon_xmac_irq,
-	.poll		= falcon_poll_xmac,
+	.check_fault	= falcon_xmac_check_fault,
 };