sfc: Implement auto-negotiation

Add infrastructure for auto-negotiation of speed, duplex and flow
control.

When using 10Xpress, auto-negotiate flow control.  While we're
at it, clean up the code to warn when partner is not 10GBASE-T
capable.

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

drivers/net/sfc/ethtool.c

@@ -12,11 +12,13 @@
 #include <linux/ethtool.h>
 #include <linux/rtnetlink.h>
 #include "net_driver.h"
+#include "workarounds.h"
 #include "selftest.h"
 #include "efx.h"
 #include "ethtool.h"
 #include "falcon.h"
 #include "spi.h"
+#include "mdio_10g.h"
 
 const char *efx_loopback_mode_names[] = {
 	[LOOPBACK_NONE]		= "NONE",
@@ -674,14 +676,51 @@ static int efx_ethtool_set_pauseparam(struct net_device *net_dev,
 				      struct ethtool_pauseparam *pause)
 {
 	struct efx_nic *efx = netdev_priv(net_dev);
-	enum efx_fc_type flow_control = efx->flow_control;
+	enum efx_fc_type wanted_fc;
+	bool reset;
 
-	flow_control &= ~(EFX_FC_RX | EFX_FC_TX | EFX_FC_AUTO);
-	flow_control |= pause->rx_pause ? EFX_FC_RX : 0;
-	flow_control |= pause->tx_pause ? EFX_FC_TX : 0;
-	flow_control |= pause->autoneg ? EFX_FC_AUTO : 0;
+	wanted_fc = ((pause->rx_pause ? EFX_FC_RX : 0) |
+		     (pause->tx_pause ? EFX_FC_TX : 0) |
+		     (pause->autoneg ? EFX_FC_AUTO : 0));
+
+	if ((wanted_fc & EFX_FC_TX) && !(wanted_fc & EFX_FC_RX)) {
+		EFX_LOG(efx, "Flow control unsupported: tx ON rx OFF\n");
+		return -EINVAL;
+	}
+
+	if (!(efx->phy_op->mmds & DEV_PRESENT_BIT(MDIO_MMD_AN)) &&
+	    (wanted_fc & EFX_FC_AUTO)) {
+		EFX_LOG(efx, "PHY does not support flow control "
+			"autonegotiation\n");
+		return -EINVAL;
+	}
+
+	/* TX flow control may automatically turn itself off if the
+	 * link partner (intermittently) stops responding to pause
+	 * frames. There isn't any indication that this has happened,
+	 * so the best we do is leave it up to the user to spot this
+	 * and fix it be cycling transmit flow control on this end. */
+	reset = (wanted_fc & EFX_FC_TX) && !(efx->wanted_fc & EFX_FC_TX);
+	if (EFX_WORKAROUND_11482(efx) && reset) {
+		if (falcon_rev(efx) >= FALCON_REV_B0) {
+			/* Recover by resetting the EM block */
+			if (efx->link_up)
+				falcon_drain_tx_fifo(efx);
+		} else {
+			/* Schedule a reset to recover */
+			efx_schedule_reset(efx, RESET_TYPE_INVISIBLE);
+		}
+	}
+
+	/* Try to push the pause parameters */
+	mutex_lock(&efx->mac_lock);
+
+	efx->wanted_fc = wanted_fc;
+	mdio_clause45_set_pause(efx);
+	__efx_reconfigure_port(efx);
+
+	mutex_unlock(&efx->mac_lock);
 
-	efx_reconfigure_port(efx);
 	return 0;
 }
 
@@ -690,9 +729,9 @@ static void efx_ethtool_get_pauseparam(struct net_device *net_dev,
 {
 	struct efx_nic *efx = netdev_priv(net_dev);
 
-	pause->rx_pause = !!(efx->flow_control & EFX_FC_RX);
-	pause->tx_pause = !!(efx->flow_control & EFX_FC_TX);
-	pause->autoneg = !!(efx->flow_control & EFX_FC_AUTO);
+	pause->rx_pause = !!(efx->wanted_fc & EFX_FC_RX);
+	pause->tx_pause = !!(efx->wanted_fc & EFX_FC_TX);
+	pause->autoneg = !!(efx->wanted_fc & EFX_FC_AUTO);
 }
 
 

drivers/net/sfc/falcon.c

@@ -1998,7 +1998,7 @@ void falcon_reconfigure_mac_wrapper(struct efx_nic *efx)
 	/* Transmission of pause frames when RX crosses the threshold is
 	 * covered by RX_XOFF_MAC_EN and XM_TX_CFG_REG:XM_FCNTL.
 	 * Action on receipt of pause frames is controller by XM_DIS_FCNTL */
-	tx_fc = !!(efx->flow_control & EFX_FC_TX);
+	tx_fc = !!(efx->link_fc & EFX_FC_TX);
 	falcon_read(efx, &reg, RX_CFG_REG_KER);
 	EFX_SET_OWORD_FIELD_VER(efx, reg, RX_XOFF_MAC_EN, tx_fc);
 
@@ -2328,9 +2328,9 @@ int falcon_probe_port(struct efx_nic *efx)
 
 	/* Hardware flow ctrl. FalconA RX FIFO too small for pause generation */
 	if (falcon_rev(efx) >= FALCON_REV_B0)
-		efx->flow_control = EFX_FC_RX | EFX_FC_TX;
+		efx->wanted_fc = EFX_FC_RX | EFX_FC_TX;
 	else
-		efx->flow_control = EFX_FC_RX;
+		efx->wanted_fc = EFX_FC_RX;
 
 	/* Allocate buffer for stats */
 	rc = falcon_alloc_buffer(efx, &efx->stats_buffer,

drivers/net/sfc/falcon_gmac.c

@@ -31,8 +31,8 @@ static void falcon_reconfigure_gmac(struct efx_nic *efx)
 	efx_oword_t reg;
 
 	/* Configuration register 1 */
-	tx_fc = (efx->flow_control & EFX_FC_TX) || !efx->link_fd;
-	rx_fc = !!(efx->flow_control & EFX_FC_RX);
+	tx_fc = (efx->link_fc & EFX_FC_TX) || !efx->link_fd;
+	rx_fc = !!(efx->link_fc & EFX_FC_RX);
 	loopback = (efx->loopback_mode == LOOPBACK_GMAC);
 	bytemode = (efx->link_speed == 1000);
 

drivers/net/sfc/falcon_xmac.c

@@ -142,7 +142,7 @@ static void falcon_reconfigure_xmac_core(struct efx_nic *efx)
 {
 	unsigned int max_frame_len;
 	efx_oword_t reg;
-	bool rx_fc = !!(efx->flow_control & EFX_FC_RX);
+	bool rx_fc = !!(efx->link_fc & EFX_FC_RX);
 
 	/* Configure MAC  - cut-thru mode is hard wired on */
 	EFX_POPULATE_DWORD_3(reg,