net: ravb: Set config mode in ndo_open and reset mode in ndo_close

As some IP variants switch to reset mode (and thus the register contents is
lost) when setting clocks (due to module standby functionality) to be able
to implement runtime PM and save more power, set the IP's operating mode to
reset at the end of the probe. Along with it, in the ndo_open API the IP
will be switched to configuration, then operation mode. In the ndo_close
API, the IP will be switched back to reset mode. This allows implementing
runtime PM and, along with it, save more power when the IP is not used.
Signed-off-by: Claudiu Beznea <claudiu.beznea.uj@bp.renesas.com>
Reviewed-by: Sergey Shtylyov <s.shtylyov@omp.ru>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

drivers/net/ethernet/renesas/ravb_main.c

@@ -1756,6 +1756,27 @@ static const struct ethtool_ops ravb_ethtool_ops = {
 	.set_wol		= ravb_set_wol,
 };
 
+static int ravb_set_config_mode(struct net_device *ndev)
+{
+	struct ravb_private *priv = netdev_priv(ndev);
+	const struct ravb_hw_info *info = priv->info;
+	int error;
+
+	if (info->gptp) {
+		error = ravb_set_opmode(ndev, CCC_OPC_CONFIG);
+		if (error)
+			return error;
+		/* Set CSEL value */
+		ravb_modify(ndev, CCC, CCC_CSEL, CCC_CSEL_HPB);
+	} else if (info->ccc_gac) {
+		error = ravb_set_opmode(ndev, CCC_OPC_CONFIG | CCC_GAC | CCC_CSEL_HPB);
+	} else {
+		error = ravb_set_opmode(ndev, CCC_OPC_CONFIG);
+	}
+
+	return error;
+}
+
 static void ravb_set_gti(struct net_device *ndev)
 {
 	struct ravb_private *priv = netdev_priv(ndev);
@@ -1864,13 +1885,19 @@ static int ravb_open(struct net_device *ndev)
 	if (info->nc_queues)
 		napi_enable(&priv->napi[RAVB_NC]);
 
+	/* Set AVB config mode */
+	error = ravb_set_config_mode(ndev);
+	if (error)
+		goto out_napi_off;
+
 	ravb_set_delay_mode(ndev);
 	ravb_write(ndev, priv->desc_bat_dma, DBAT);
 
 	/* Device init */
 	error = ravb_dmac_init(ndev);
 	if (error)
-		goto out_napi_off;
+		goto out_set_reset;
+
 	ravb_emac_init(ndev);
 
 	ravb_set_gti(ndev);
@@ -1893,6 +1920,8 @@ static int ravb_open(struct net_device *ndev)
 	if (info->gptp || info->ccc_gac)
 		ravb_ptp_stop(ndev);
 	ravb_stop_dma(ndev);
+out_set_reset:
+	ravb_set_opmode(ndev, CCC_OPC_RESET);
 out_napi_off:
 	if (info->nc_queues)
 		napi_disable(&priv->napi[RAVB_NC]);
@@ -2236,7 +2265,8 @@ static int ravb_close(struct net_device *ndev)
 	if (info->nc_queues)
 		ravb_ring_free(ndev, RAVB_NC);
 
-	return 0;
+	/* Set reset mode. */
+	return ravb_set_opmode(ndev, CCC_OPC_RESET);
 }
 
 static int ravb_hwtstamp_get(struct net_device *ndev, struct ifreq *req)
@@ -2566,27 +2596,6 @@ static const struct of_device_id ravb_match_table[] = {
 };
 MODULE_DEVICE_TABLE(of, ravb_match_table);
 
-static int ravb_set_config_mode(struct net_device *ndev)
-{
-	struct ravb_private *priv = netdev_priv(ndev);
-	const struct ravb_hw_info *info = priv->info;
-	int error;
-
-	if (info->gptp) {
-		error = ravb_set_opmode(ndev, CCC_OPC_CONFIG);
-		if (error)
-			return error;
-		/* Set CSEL value */
-		ravb_modify(ndev, CCC, CCC_CSEL, CCC_CSEL_HPB);
-	} else if (info->ccc_gac) {
-		error = ravb_set_opmode(ndev, CCC_OPC_CONFIG | CCC_GAC | CCC_CSEL_HPB);
-	} else {
-		error = ravb_set_opmode(ndev, CCC_OPC_CONFIG);
-	}
-
-	return error;
-}
-
 static int ravb_setup_irq(struct ravb_private *priv, const char *irq_name,
 			  const char *ch, int *irq, irq_handler_t handler)
 {
@@ -2785,11 +2794,6 @@ static int ravb_probe(struct platform_device *pdev)
 	ndev->netdev_ops = &ravb_netdev_ops;
 	ndev->ethtool_ops = &ravb_ethtool_ops;
 
-	/* Set AVB config mode */
-	error = ravb_set_config_mode(ndev);
-	if (error)
-		goto out_rpm_put;
-
 	error = ravb_compute_gti(ndev);
 	if (error)
 		goto out_rpm_put;
@@ -2816,6 +2820,11 @@ static int ravb_probe(struct platform_device *pdev)
 	/* Debug message level */
 	priv->msg_enable = RAVB_DEF_MSG_ENABLE;
 
+	/* Set config mode as this is needed for PHY initialization. */
+	error = ravb_set_opmode(ndev, CCC_OPC_CONFIG);
+	if (error)
+		goto out_rpm_put;
+
 	/* Read and set MAC address */
 	ravb_read_mac_address(np, ndev);
 	if (!is_valid_ether_addr(ndev->dev_addr)) {
@@ -2828,9 +2837,14 @@ static int ravb_probe(struct platform_device *pdev)
 	error = ravb_mdio_init(priv);
 	if (error) {
 		dev_err(&pdev->dev, "failed to initialize MDIO\n");
-		goto out_dma_free;
+		goto out_reset_mode;
 	}
 
+	/* Undo previous switch to config opmode. */
+	error = ravb_set_opmode(ndev, CCC_OPC_RESET);
+	if (error)
+		goto out_mdio_release;
+
 	netif_napi_add(ndev, &priv->napi[RAVB_BE], ravb_poll);
 	if (info->nc_queues)
 		netif_napi_add(ndev, &priv->napi[RAVB_NC], ravb_poll);
@@ -2853,8 +2867,10 @@ static int ravb_probe(struct platform_device *pdev)
 		netif_napi_del(&priv->napi[RAVB_NC]);
 
 	netif_napi_del(&priv->napi[RAVB_BE]);
+out_mdio_release:
 	ravb_mdio_release(priv);
-out_dma_free:
+out_reset_mode:
+	ravb_set_opmode(ndev, CCC_OPC_RESET);
 	dma_free_coherent(ndev->dev.parent, priv->desc_bat_size, priv->desc_bat,
 			  priv->desc_bat_dma);
 out_rpm_put:
@@ -2885,8 +2901,6 @@ static void ravb_remove(struct platform_device *pdev)
 	dma_free_coherent(ndev->dev.parent, priv->desc_bat_size, priv->desc_bat,
 			  priv->desc_bat_dma);
 
-	ravb_set_opmode(ndev, CCC_OPC_RESET);
-
 	pm_runtime_put_sync(&pdev->dev);
 	pm_runtime_disable(&pdev->dev);
 	clk_unprepare(priv->refclk);