gve: Enable Link Speed Reporting in the driver.

This change allows the driver to report the device link speed
when the ethtool command:
	ethtool <nic name>
is run.
Getting the link speed is done via a new admin queue command:
ReportLinkSpeed.
Reviewed-by: Yangchun Fu <yangchun@google.com>
Signed-off-by: David Awogbemila <awogbemila@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/google/gve/gve.h

@@ -232,6 +232,7 @@ struct gve_priv {
 	u32 adminq_dcfg_device_resources_cnt;
 	u32 adminq_set_driver_parameter_cnt;
 	u32 adminq_report_stats_cnt;
+	u32 adminq_report_link_speed_cnt;
 
 	/* Global stats */
 	u32 interface_up_cnt; /* count of times interface turned up since last reset */
@@ -254,6 +255,8 @@ struct gve_priv {
 	unsigned long stats_report_timer_period;
 	struct timer_list stats_report_timer;
 
+	/* Gvnic device link speed from hypervisor. */
+	u64 link_speed;
 };
 
 enum gve_service_task_flags_bit {

drivers/net/ethernet/google/gve/gve_adminq.c

@@ -36,6 +36,7 @@ int gve_adminq_alloc(struct device *dev, struct gve_priv *priv)
 	priv->adminq_dcfg_device_resources_cnt = 0;
 	priv->adminq_set_driver_parameter_cnt = 0;
 	priv->adminq_report_stats_cnt = 0;
+	priv->adminq_report_link_speed_cnt = 0;
 
 	/* Setup Admin queue with the device */
 	iowrite32be(priv->adminq_bus_addr / PAGE_SIZE,
@@ -238,6 +239,9 @@ static int gve_adminq_issue_cmd(struct gve_priv *priv,
 	case GVE_ADMINQ_REPORT_STATS:
 		priv->adminq_report_stats_cnt++;
 		break;
+	case GVE_ADMINQ_REPORT_LINK_SPEED:
+		priv->adminq_report_link_speed_cnt++;
+		break;
 	default:
 		dev_err(&priv->pdev->dev, "unknown AQ command opcode %d\n", opcode);
 	}
@@ -595,3 +599,30 @@ int gve_adminq_report_stats(struct gve_priv *priv, u64 stats_report_len,
 
 	return gve_adminq_execute_cmd(priv, &cmd);
 }
+
+int gve_adminq_report_link_speed(struct gve_priv *priv)
+{
+	union gve_adminq_command gvnic_cmd;
+	dma_addr_t link_speed_region_bus;
+	__be64 *link_speed_region;
+	int err;
+
+	link_speed_region =
+		dma_alloc_coherent(&priv->pdev->dev, sizeof(*link_speed_region),
+				   &link_speed_region_bus, GFP_KERNEL);
+
+	if (!link_speed_region)
+		return -ENOMEM;
+
+	memset(&gvnic_cmd, 0, sizeof(gvnic_cmd));
+	gvnic_cmd.opcode = cpu_to_be32(GVE_ADMINQ_REPORT_LINK_SPEED);
+	gvnic_cmd.report_link_speed.link_speed_address =
+		cpu_to_be64(link_speed_region_bus);
+
+	err = gve_adminq_execute_cmd(priv, &gvnic_cmd);
+
+	priv->link_speed = be64_to_cpu(*link_speed_region);
+	dma_free_coherent(&priv->pdev->dev, sizeof(*link_speed_region), link_speed_region,
+			  link_speed_region_bus);
+	return err;
+}

drivers/net/ethernet/google/gve/gve_adminq.h

@@ -22,6 +22,7 @@ enum gve_adminq_opcodes {
 	GVE_ADMINQ_DECONFIGURE_DEVICE_RESOURCES	= 0x9,
 	GVE_ADMINQ_SET_DRIVER_PARAMETER		= 0xB,
 	GVE_ADMINQ_REPORT_STATS			= 0xC,
+	GVE_ADMINQ_REPORT_LINK_SPEED	= 0xD
 };
 
 /* Admin queue status codes */
@@ -181,6 +182,12 @@ struct gve_adminq_report_stats {
 
 static_assert(sizeof(struct gve_adminq_report_stats) == 24);
 
+struct gve_adminq_report_link_speed {
+	__be64 link_speed_address;
+};
+
+static_assert(sizeof(struct gve_adminq_report_link_speed) == 8);
+
 struct stats {
 	__be32 stat_name;
 	__be32 queue_id;
@@ -228,6 +235,7 @@ union gve_adminq_command {
 			struct gve_adminq_unregister_page_list unreg_page_list;
 			struct gve_adminq_set_driver_parameter set_driver_param;
 			struct gve_adminq_report_stats report_stats;
+			struct gve_adminq_report_link_speed report_link_speed;
 		};
 	};
 	u8 reserved[64];
@@ -255,4 +263,5 @@ int gve_adminq_unregister_page_list(struct gve_priv *priv, u32 page_list_id);
 int gve_adminq_set_mtu(struct gve_priv *priv, u64 mtu);
 int gve_adminq_report_stats(struct gve_priv *priv, u64 stats_report_len,
 			    dma_addr_t stats_report_addr, u64 interval);
+int gve_adminq_report_link_speed(struct gve_priv *priv);
 #endif /* _GVE_ADMINQ_H */

drivers/net/ethernet/google/gve/gve_ethtool.c

@@ -59,7 +59,7 @@ static const char gve_gstrings_adminq_stats[][ETH_GSTRING_LEN] = {
 	"adminq_create_tx_queue_cnt", "adminq_create_rx_queue_cnt",
 	"adminq_destroy_tx_queue_cnt", "adminq_destroy_rx_queue_cnt",
 	"adminq_dcfg_device_resources_cnt", "adminq_set_driver_parameter_cnt",
-	"adminq_report_stats_cnt",
+	"adminq_report_stats_cnt", "adminq_report_link_speed_cnt"
 };
 
 static const char gve_gstrings_priv_flags[][ETH_GSTRING_LEN] = {
@@ -355,6 +355,7 @@ gve_get_ethtool_stats(struct net_device *netdev,
 	data[i++] = priv->adminq_dcfg_device_resources_cnt;
 	data[i++] = priv->adminq_set_driver_parameter_cnt;
 	data[i++] = priv->adminq_report_stats_cnt;
+	data[i++] = priv->adminq_report_link_speed_cnt;
 }
 
 static void gve_get_channels(struct net_device *netdev,
@@ -505,6 +506,16 @@ static int gve_set_priv_flags(struct net_device *netdev, u32 flags)
 	return 0;
 }
 
+static int gve_get_link_ksettings(struct net_device *netdev,
+				  struct ethtool_link_ksettings *cmd)
+{
+	struct gve_priv *priv = netdev_priv(netdev);
+	int err = gve_adminq_report_link_speed(priv);
+
+	cmd->base.speed = priv->link_speed;
+	return err;
+}
+
 const struct ethtool_ops gve_ethtool_ops = {
 	.get_drvinfo = gve_get_drvinfo,
 	.get_strings = gve_get_strings,
@@ -521,4 +532,5 @@ const struct ethtool_ops gve_ethtool_ops = {
 	.set_tunable = gve_set_tunable,
 	.get_priv_flags = gve_get_priv_flags,
 	.set_priv_flags = gve_set_priv_flags,
+	.get_link_ksettings = gve_get_link_ksettings
 };