sfc: Minimal support for 40G link speed

Accept and handle 40G link events.

Accept ethtool link settings of speed == 40000 && duplex, and set the
appropriate MCDI PHY capability.

This does not include reporting of 40G media types, as those have not
yet been assigned numbers in the MCDI protocol.
Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>

drivers/net/ethernet/sfc/Kconfig

@@ -7,7 +7,7 @@ config SFC
 	select I2C_ALGOBIT
 	select PTP_1588_CLOCK
 	---help---
-	  This driver supports 10-gigabit Ethernet cards based on
+	  This driver supports 10/40-gigabit Ethernet cards based on
 	  the Solarflare SFC4000, SFC9000-family and SFC9100-family
 	  controllers.
 

drivers/net/ethernet/sfc/mcdi_port.c

@@ -556,6 +556,7 @@ static int efx_mcdi_phy_set_settings(struct efx_nic *efx, struct ethtool_cmd *ec
 		case 100:   caps = 1 << MC_CMD_PHY_CAP_100FDX_LBN;   break;
 		case 1000:  caps = 1 << MC_CMD_PHY_CAP_1000FDX_LBN;  break;
 		case 10000: caps = 1 << MC_CMD_PHY_CAP_10000FDX_LBN; break;
+		case 40000: caps = 1 << MC_CMD_PHY_CAP_40000FDX_LBN; break;
 		default:    return -EINVAL;
 		}
 	} else {
@@ -841,6 +842,7 @@ static unsigned int efx_mcdi_event_link_speed[] = {
 	[MCDI_EVENT_LINKCHANGE_SPEED_100M] = 100,
 	[MCDI_EVENT_LINKCHANGE_SPEED_1G] = 1000,
 	[MCDI_EVENT_LINKCHANGE_SPEED_10G] = 10000,
+	[MCDI_EVENT_LINKCHANGE_SPEED_40G] = 40000,
 };
 
 void efx_mcdi_process_link_change(struct efx_nic *efx, efx_qword_t *ev)