On Fri, Sep 08, 2017 at 03:05:20PM +0200, Andrew Lunn wrote:

quoted

+#define DWMAC_sUN8I_MDIO_MUX_INTERNAL_ID	0
+#define DWMAC_sUN8I_MDIO_MUX_EXTERNAL_ID	1
 
 /* H3/A64 specific bits */
 #define SYSCON_RMII_EN		BIT(13) /* 1: enable RMII (overrides EPIT) */

@@ -634,6 +639,76 @@ static int sun8i_dwmac_reset(struct stmmac_priv *priv)
 	return 0;
 }
 
+/* MDIO multiplexing switch function
+ * This function is called by the mdio-mux layer when it thinks the mdio bus
+ * multiplexer needs to switch.
+ * 'current_child' is the current value of the mux register
+ * 'desired_child' is the value of the 'reg' property of the target child MDIO
+ * node.
+ * The first time this function is called, current_child == -1.
+ * If current_child == desired_child, then the mux is already set to the
+ * correct bus.
+ *
+ * Note that we do not use reg/mask like mdio-mux-mmioreg because we need to
+ * know easily which bus is used (reset must be done only for desired bus).
+ */
+static int mdio_mux_syscon_switch_fn(int current_child, int desired_child,
+				     void *data)
+{
+	struct stmmac_priv *priv = data;
+	struct sunxi_priv_data *gmac = priv->plat->bsp_priv;
+	u32 reg, val;
+	int ret = 0;
+	bool need_reset = false;
+
+	if (current_child ^ desired_child) {
+		regmap_read(gmac->regmap, SYSCON_EMAC_REG, &reg);
+		switch (desired_child) {
+		case DWMAC_sUN8I_MDIO_MUX_INTERNAL_ID:
+			dev_info(priv->device, "Switch mux to internal PHY");
+			val = (reg & ~H3_EPHY_MUX_MASK) | H3_EPHY_SELECT;
+			if (gmac->use_internal_phy)
+				need_reset = true;
+			break;

This i don't get. Why do you need use_internal_phy? Isn't that
implicit from DWMAC_sUN8I_MDIO_MUX_INTERNAL_ID? Is it even possible to
use an external PHY on the internal MDIO bus?

On my H3 box with external PHY, the MDIO mux library first select (for scan ?) the internal MDIO.
Without use_internal_phy usage, this board will launch a reset to use the internal MDIO... and this reset timeout/fail.
After the MDIO mux select the external MDIO.

quoted

+		case DWMAC_sUN8I_MDIO_MUX_EXTERNAL_ID:
+			dev_info(priv->device, "Switch mux to external PHY");
+			val = (reg & ~H3_EPHY_MUX_MASK) | H3_EPHY_SHUTDOWN;
+			if (!gmac->use_internal_phy)
+				need_reset = true;
+			break;

And is it possible to use the internal PHY on the external bus?

I need to check that.

Regards