[PATCH net-next 2/3] net: macb: Added ZynqMP-specific initialization

[Robert Hancock <robert.hancock@calian.com>]

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 when it is initializing.

Signed-off-by: Robert Hancock <robert.hancock@calian.com>
---
 drivers/net/ethernet/cadence/macb_main.c | 47 +++++++++++++++++++++++-
 1 file changed, 46 insertions(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/cadence/macb_main.c b/drivers/net/ethernet/cadence/macb_main.c
index a363da928e8b..65b0360c487a 100644
--- a/drivers/net/ethernet/cadence/macb_main.c
+++ b/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 */
@@ -4455,6 +4457,49 @@ static int fu540_c000_init(struct platform_device *pdev)
 	return macb_init(pdev);
 }
 
+static int zynqmp_init(struct platform_device *pdev)
+{
+	struct net_device *dev = platform_get_drvdata(pdev);
+	struct macb *bp = netdev_priv(dev);
+	int ret;
+
+	/* Fully reset GEM controller at hardware level using zynqmp-reset driver,
+	 * if mapped in device tree.
+	 */
+	ret = device_reset(&pdev->dev);
+	if (ret) {
+		dev_err_probe(&pdev->dev, ret, "failed to reset controller");
+		return ret;
+	}
+
+	if (bp->phy_interface == PHY_INTERFACE_MODE_SGMII) {
+		/* Ensure PS-GTR PHY device used in SGMII mode is ready */
+		struct phy *sgmii_phy = devm_phy_get(&pdev->dev, "sgmii-phy");
+
+		if (IS_ERR(sgmii_phy)) {
+			ret = PTR_ERR(sgmii_phy);
+			dev_err_probe(&pdev->dev, ret,
+				      "failed to get PS-GTR PHY\n");
+			return ret;
+		}
+
+		ret = phy_init(sgmii_phy);
+		if (ret) {
+			dev_err(&pdev->dev, "failed to init PS-GTR PHY: %d\n",
+				ret);
+			return ret;
+		}
+
+		ret = phy_power_on(sgmii_phy);
+		if (ret) {
+			dev_err(&pdev->dev, "failed to power on PS-GTR PHY: %d\n",
+				ret);
+			return ret;
+		}
+	}
+	return macb_init(pdev);
+}
+
 static const struct macb_usrio_config sama7g5_usrio = {
 	.mii = 0,
 	.rmii = 1,
@@ -4550,7 +4595,7 @@ static const struct macb_config zynqmp_config = {
 			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,
 };
-- 
2.31.1