net: macb: Added ZynqMP-specific initialization

The GEM controllers on ZynqMP were missing some initialization steps which
are required in some cases when using SGMII mode, which uses the PS-GTR
transceivers managed by the phy-zynqmp driver.

The GEM core appears to need a hardware-level reset in order to work
properly in SGMII mode in cases where the GT reference clock was not
present at initial power-on. This can be done using a reset mapped to
the zynqmp-reset driver in the device tree.

Also, when in SGMII mode, the GEM driver needs to ensure the PHY is
initialized and powered on.

Signed-off-by: Robert Hancock <robert.hancock@calian.com>
Reviewed-by: Claudiu Beznea <claudiu.beznea@microchip.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Author: robhancocksed

drivers/net/ethernet/cadence/macb.h

@@ -12,6 +12,7 @@
 #include <linux/ptp_clock_kernel.h>
 #include <linux/net_tstamp.h>
 #include <linux/interrupt.h>
+#include <linux/phy/phy.h>
 
 #if defined(CONFIG_ARCH_DMA_ADDR_T_64BIT) || defined(CONFIG_MACB_USE_HWSTAMP)
 #define MACB_EXT_DESC
@@ -1290,6 +1291,9 @@ struct macb {
 	u32			wol;
 
 	struct macb_ptp_info	*ptp_info;	/* macb-ptp interface */
+
+	struct phy		*sgmii_phy;	/* for ZynqMP SGMII mode */
+
 #ifdef MACB_EXT_DESC
 	uint8_t hw_dma_cap;
 #endif

drivers/net/ethernet/cadence/macb_main.c

@@ -34,7 +34,9 @@
 #include <linux/udp.h>
 #include <linux/tcp.h>
 #include <linux/iopoll.h>
+#include <linux/phy/phy.h>
 #include <linux/pm_runtime.h>
+#include <linux/reset.h>
 #include "macb.h"
 
 /* This structure is only used for MACB on SiFive FU540 devices */
@@ -2785,17 +2787,24 @@ static int macb_open(struct net_device *dev)
 
 	macb_init_hw(bp);
 
-	err = macb_phylink_connect(bp);
+	err = phy_power_on(bp->sgmii_phy);
 	if (err)
 		goto reset_hw;
 
+	err = macb_phylink_connect(bp);
+	if (err)
+		goto phy_off;
+
 	netif_tx_start_all_queues(dev);
 
 	if (bp->ptp_info)
 		bp->ptp_info->ptp_init(dev);
 
 	return 0;
 
+phy_off:
+	phy_power_off(bp->sgmii_phy);
+
 reset_hw:
 	macb_reset_hw(bp);
 	for (q = 0, queue = bp->queues; q < bp->num_queues; ++q, ++queue)
@@ -2821,6 +2830,8 @@ static int macb_close(struct net_device *dev)
 	phylink_stop(bp->phylink);
 	phylink_disconnect_phy(bp->phylink);
 
+	phy_power_off(bp->sgmii_phy);
+
 	spin_lock_irqsave(&bp->lock, flags);
 	macb_reset_hw(bp);
 	netif_carrier_off(dev);
@@ -4586,13 +4597,55 @@ static const struct macb_config np4_config = {
 	.usrio = &macb_default_usrio,
 };
 
+static int zynqmp_init(struct platform_device *pdev)
+{
+	struct net_device *dev = platform_get_drvdata(pdev);
+	struct macb *bp = netdev_priv(dev);
+	int ret;
+
+	if (bp->phy_interface == PHY_INTERFACE_MODE_SGMII) {
+		/* Ensure PS-GTR PHY device used in SGMII mode is ready */
+		bp->sgmii_phy = devm_phy_get(&pdev->dev, "sgmii-phy");
+
+		if (IS_ERR(bp->sgmii_phy)) {
+			ret = PTR_ERR(bp->sgmii_phy);
+			dev_err_probe(&pdev->dev, ret,
+				      "failed to get PS-GTR PHY\n");
+			return ret;
+		}
+
+		ret = phy_init(bp->sgmii_phy);
+		if (ret) {
+			dev_err(&pdev->dev, "failed to init PS-GTR PHY: %d\n",
+				ret);
+			return ret;
+		}
+	}
+
+	/* Fully reset GEM controller at hardware level using zynqmp-reset driver,
+	 * if mapped in device tree.
+	 */
+	ret = device_reset_optional(&pdev->dev);
+	if (ret) {
+		dev_err_probe(&pdev->dev, ret, "failed to reset controller");
+		phy_exit(bp->sgmii_phy);
+		return ret;
+	}
+
+	ret = macb_init(pdev);
+	if (ret)
+		phy_exit(bp->sgmii_phy);
+
+	return ret;
+}
+
 static const struct macb_config zynqmp_config = {
 	.caps = MACB_CAPS_GIGABIT_MODE_AVAILABLE |
 			MACB_CAPS_JUMBO |
 			MACB_CAPS_GEM_HAS_PTP | MACB_CAPS_BD_RD_PREFETCH,
 	.dma_burst_length = 16,
 	.clk_init = macb_clk_init,
-	.init = macb_init,
+	.init = zynqmp_init,
 	.jumbo_max_len = 10240,
 	.usrio = &macb_default_usrio,
 };
@@ -4809,7 +4862,7 @@ static int macb_probe(struct platform_device *pdev)
 
 	err = macb_mii_init(bp);
 	if (err)
-		goto err_out_free_netdev;
+		goto err_out_phy_exit;
 
 	netif_carrier_off(dev);
 
@@ -4834,6 +4887,9 @@ static int macb_probe(struct platform_device *pdev)
 	mdiobus_unregister(bp->mii_bus);
 	mdiobus_free(bp->mii_bus);
 
+err_out_phy_exit:
+	phy_exit(bp->sgmii_phy);
+
 err_out_free_netdev:
 	free_netdev(dev);
 
@@ -4855,6 +4911,7 @@ static int macb_remove(struct platform_device *pdev)
 
 	if (dev) {
 		bp = netdev_priv(dev);
+		phy_exit(bp->sgmii_phy);
 		mdiobus_unregister(bp->mii_bus);
 		mdiobus_free(bp->mii_bus);