Subject: Re: [PATCH v6 05/11] dt-bindings: net: dwmac-sun8i: update documentation about integrated PHY

From: Corentin Labbe <[email-masked]>
Date: Sun, 8 Oct 2017 20:33:40 +0200

On Thu, Sep 28, 2017 at 09:37:08AM +0200, Corentin Labbe wrote:
> On Wed, Sep 27, 2017 at 04:02:10PM +0200, Andrew Lunn wrote:
> > Hi Corentin
> > 
> > > +Required properties for the mdio-mux node:
> > > +  - compatible = "mdio-mux"
> > 
> > This is too generic. Please add a more specific compatible for this
> > particular mux. You can keep "mdio-mux", since that is what the MDIO
> > subsystem will look for.
> > 
> 
> I will add allwinner,sun8i-h3-mdio-mux
> 
> > > +Required properties of the integrated phy node:
> > >  - clocks: a phandle to the reference clock for the EPHY
> > >  - resets: a phandle to the reset control for the EPHY
> > > +- phy-is-integrated
> > 
> > So the last thing you said is that the mux is not the problem
> > here. Something else is locking up. Did you discover what?
> > 
> > I really would like phy-is-integrated to go away.
> > 
> 
> I have found the problem: by enabling ephy clk/reset the timeout does not occur anymore.
> So we could remove phy-is-integrated by:
> Moving internal phy clk/reset handling in mdio_mux_syscon_switch_fn()
> But this means:
> - getting internalphy node always by manually get internal_mdio/internal_phy (and not by the given phyhandle)
> - doing some unnecessary tasks (enable/scan/disable) when external_phy is needed
> 
> Regards

Hello all

Below is the current patch, as you can read, it does not use anymore the phy-is-integrated property.
So now, the mdio-mux must always enable the internal mdio when switch_fn ask for it and so reset MAC and so need to enable ephy clk/reset.
But for this I need a reference to thoses clock and reset. (this is done in get_ephy_nodes)
The current version set those clock in mdio-mux node, and as you can see it is already ugly (lots of get next node),
if the clk/rst nodes were as it should be, in phy nodes, it will be more bad.

So, since the MAC have a dependency on thoses clk/rst nodes for doing reset(), I seek a proper way to get references on it.
OR do you agree that putting ephy clk/rst in emac is acceptable ?

thanks
regards

--- a/drivers/net/ethernet/stmicro/stmmac/dwmac-sun8i.c
+++ b/drivers/net/ethernet/stmicro/stmmac/dwmac-sun8i.c
@@ -17,6 +17,7 @@
 #include <linux/clk.h>
 #include <linux/io.h>
 #include <linux/iopoll.h>
+#include <linux/mdio-mux.h>
 #include <linux/mfd/syscon.h>
 #include <linux/module.h>
 #include <linux/of_device.h>
@@ -41,14 +42,14 @@
  *				This value is used for disabling properly EMAC
  *				and used as a good starting value in case of the
  *				boot process(uboot) leave some stuff.
- * @internal_phy:		Does the MAC embed an internal PHY
+ * @soc_has_internal_phy:	Does the MAC embed an internal PHY
  * @support_mii:		Does the MAC handle MII
  * @support_rmii:		Does the MAC handle RMII
  * @support_rgmii:		Does the MAC handle RGMII
  */
 struct emac_variant {
 	u32 default_syscon_value;
-	int internal_phy;
+	bool soc_has_internal_phy;
 	bool support_mii;
 	bool support_rmii;
 	bool support_rgmii;
@@ -61,7 +62,7 @@ struct emac_variant {
  * @rst_ephy:	reference to the optional EPHY reset for the internal PHY
  * @variant:	reference to the current board variant
  * @regmap:	regmap for using the syscon
- * @use_internal_phy: Does the current PHY choice imply using the internal PHY
+ * @internal_phy_powered: Does the internal PHY is enabled
  */
 struct sunxi_priv_data {
 	struct clk *tx_clk;
@@ -70,12 +71,13 @@ struct sunxi_priv_data {
 	struct reset_control *rst_ephy;
 	const struct emac_variant *variant;
 	struct regmap *regmap;
-	bool use_internal_phy;
+	bool internal_phy_powered;
+	void *mux_handle;
 };
 
 static const struct emac_variant emac_variant_h3 = {
 	.default_syscon_value = 0x58000,
-	.internal_phy = PHY_INTERFACE_MODE_MII,
+	.soc_has_internal_phy = true,
 	.support_mii = true,
 	.support_rmii = true,
 	.support_rgmii = true
@@ -83,20 +85,20 @@ static const struct emac_variant emac_variant_h3 = {
 
 static const struct emac_variant emac_variant_v3s = {
 	.default_syscon_value = 0x38000,
-	.internal_phy = PHY_INTERFACE_MODE_MII,
+	.soc_has_internal_phy = true,
 	.support_mii = true
 };
 
 static const struct emac_variant emac_variant_a83t = {
 	.default_syscon_value = 0,
-	.internal_phy = 0,
+	.soc_has_internal_phy = false,
 	.support_mii = true,
 	.support_rgmii = true
 };
 
 static const struct emac_variant emac_variant_a64 = {
 	.default_syscon_value = 0,
-	.internal_phy = 0,
+	.soc_has_internal_phy = false,
 	.support_mii = true,
 	.support_rmii = true,
 	.support_rgmii = true
@@ -195,6 +197,9 @@ static const struct emac_variant emac_variant_a64 = {
 #define H3_EPHY_LED_POL		BIT(17) /* 1: active low, 0: active high */
 #define H3_EPHY_SHUTDOWN	BIT(16) /* 1: shutdown, 0: power up */
 #define H3_EPHY_SELECT		BIT(15) /* 1: internal PHY, 0: external PHY */
+#define H3_EPHY_MUX_MASK	(H3_EPHY_SHUTDOWN | H3_EPHY_SELECT)
+#define DWMAC_SUN8I_MDIO_MUX_INTERNAL_ID	1
+#define DWMAC_SUN8I_MDIO_MUX_EXTERNAL_ID	2
 
 /* H3/A64 specific bits */
 #define SYSCON_RMII_EN		BIT(13) /* 1: enable RMII (overrides EPIT) */
@@ -634,6 +639,164 @@ static int sun8i_dwmac_reset(struct stmmac_priv *priv)
 	return 0;
 }
 
+static int get_ephy_nodes(struct stmmac_priv *priv)
+{
+	struct sunxi_priv_data *gmac = priv->plat->bsp_priv;
+	struct device_node *mdio_mux;
+	struct device_node *mdio_internal;
+	int ret;
+
+	mdio_mux = of_get_child_by_name(priv->plat->mdio_node, "mdio-mux");
+	if (!mdio_mux) {
+		dev_err(priv->device, "Cannot get mdio-mux node\n");
+		return -ENODEV;
+	}
+
+	mdio_internal = of_find_compatible_node(mdio_mux, NULL,
+						"allwinner,sun8i-h3-mdio-internal");
+	if (!mdio_internal) {
+		dev_err(priv->device, "Cannot get internal_mdio node\n");
+		return -ENODEV;
+	}
+
+	/* insert here code to get child phynode */
+	gmac->ephy_clk = of_clk_get(mdio_internal, 0);
+	if (IS_ERR(gmac->ephy_clk)) {
+		ret = PTR_ERR(gmac->ephy_clk);
+		dev_err(priv->device, "Cannot get EPHY clock: %d\n", ret);
+		return -EINVAL;
+	}
+
+	/* Note that we cannot use devm_reset_control_get, since
+	 * the reset is not in the device node.
+	 */
+	gmac->rst_ephy = of_reset_control_get_exclusive(mdio_internal, NULL);
+	if (IS_ERR(gmac->rst_ephy)) {
+		ret = PTR_ERR(gmac->rst_ephy);
+		if (ret == -EPROBE_DEFER)
+			return ret;
+		dev_err(priv->device, "No EPHY reset control found %d\n", ret);
+		return -EINVAL;
+	}
+	return 0;
+}
+
+static int sun8i_dwmac_power_internal_phy(struct stmmac_priv *priv)
+{
+	struct sunxi_priv_data *gmac = priv->plat->bsp_priv;
+	int ret;
+
+	if (gmac->internal_phy_powered) {
+		dev_warn(priv->device, "Internal PHY already powered\n");
+		return 0;
+	}
+
+	dev_info(priv->device, "Powering internal PHY\n");
+	ret = clk_prepare_enable(gmac->ephy_clk);
+	if (ret) {
+		dev_err(priv->device, "Cannot enable internal PHY\n");
+		return ret;
+	}
+
+	/* Make sure the EPHY is properly reseted, as U-Boot may leave
+	 * it at deasserted state, and thus it may fail to reset EMAC.
+	 */
+	reset_control_assert(gmac->rst_ephy);
+
+	ret = reset_control_deassert(gmac->rst_ephy);
+	if (ret) {
+		dev_err(priv->device, "Cannot deassert internal phy\n");
+		clk_disable_unprepare(gmac->ephy_clk);
+		return ret;
+	}
+
+	gmac->internal_phy_powered = true;
+
+	return 0;
+}
+
+static int sun8i_dwmac_unpower_internal_phy(struct sunxi_priv_data *gmac)
+{
+	if (!gmac->internal_phy_powered)
+		return 0;
+
+	clk_disable_unprepare(gmac->ephy_clk);
+	reset_control_assert(gmac->rst_ephy);
+	gmac->internal_phy_powered = false;
+	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_power_ephy = 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;
+
+			need_power_ephy = true;
+			break;
+		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;
+			need_power_ephy = false;
+			break;
+		default:
+			dev_err(priv->device, "Invalid child ID %x\n",
+				desired_child);
+			return -EINVAL;
+		}
+		regmap_write(gmac->regmap, SYSCON_EMAC_REG, val);
+		if (need_power_ephy) {
+			ret = sun8i_dwmac_power_internal_phy(priv);
+			if (ret)
+				return ret;
+		} else {
+			sun8i_dwmac_unpower_internal_phy(gmac);
+		}
+		/* After changing syscon value, the MAC need reset or it will
+		 * use the last value (and so the last PHY set).
+		 */
+		ret = sun8i_dwmac_reset(priv);
+	}
+	return ret;
+}
+
+static int sun8i_dwmac_register_mdio_mux(struct stmmac_priv *priv)
+{
+	int ret;
+	struct device_node *mdio_mux;
+	struct sunxi_priv_data *gmac = priv->plat->bsp_priv;
+
+	mdio_mux = of_get_child_by_name(priv->plat->mdio_node, "mdio-mux");
+	if (!mdio_mux)
+		return -ENODEV;
+
+	ret = mdio_mux_init(priv->device, mdio_mux, mdio_mux_syscon_switch_fn,
+			    &gmac->mux_handle, priv, priv->mii);
+	return ret;
+}
+
 static int sun8i_dwmac_set_syscon(struct stmmac_priv *priv)
 {
 	struct sunxi_priv_data *gmac = priv->plat->bsp_priv;
@@ -648,35 +811,25 @@ static int sun8i_dwmac_set_syscon(struct stmmac_priv *priv)
 			 "Current syscon value is not the default %x (expect %x)\n",
 			 val, reg);
 
-	if (gmac->variant->internal_phy) {
-		if (!gmac->use_internal_phy) {
-			/* switch to external PHY interface */
-			reg &= ~H3_EPHY_SELECT;
-		} else {
-			reg |= H3_EPHY_SELECT;
-			reg &= ~H3_EPHY_SHUTDOWN;
-			dev_dbg(priv->device, "Select internal_phy %x\n", reg);
-
-			if (of_property_read_bool(priv->plat->phy_node,
-						  "allwinner,leds-active-low"))
-				reg |= H3_EPHY_LED_POL;
-			else
-				reg &= ~H3_EPHY_LED_POL;
-
-			/* Force EPHY xtal frequency to 24MHz. */
-			reg |= H3_EPHY_CLK_SEL;
-
-			ret = of_mdio_parse_addr(priv->device,
-						 priv->plat->phy_node);
-			if (ret < 0) {
-				dev_err(priv->device, "Could not parse MDIO addr\n");
-				return ret;
-			}
-			/* of_mdio_parse_addr returns a valid (0 ~ 31) PHY
-			 * address. No need to mask it again.
-			 */
-			reg |= ret << H3_EPHY_ADDR_SHIFT;
+	if (gmac->variant->soc_has_internal_phy) {
+		if (of_property_read_bool(priv->plat->phy_node,
+					  "allwinner,leds-active-low"))
+			reg |= H3_EPHY_LED_POL;
+		else
+			reg &= ~H3_EPHY_LED_POL;
+
+		/* Force EPHY xtal frequency to 24MHz. */
+		reg |= H3_EPHY_CLK_SEL;
+
+		ret = of_mdio_parse_addr(priv->device, priv->plat->phy_node);
+		if (ret < 0) {
+			dev_err(priv->device, "Could not parse MDIO addr\n");
+			return ret;
 		}
+		/* of_mdio_parse_addr returns a valid (0 ~ 31) PHY
+		 * address. No need to mask it again.
+		 */
+		reg |= 1 << H3_EPHY_ADDR_SHIFT;
 	}
 
 	if (!of_property_read_u32(node, "allwinner,tx-delay-ps", &val)) {
@@ -746,81 +899,21 @@ static void sun8i_dwmac_unset_syscon(struct sunxi_priv_data *gmac)
 	regmap_write(gmac->regmap, SYSCON_EMAC_REG, reg);
 }
 
-static int sun8i_dwmac_power_internal_phy(struct stmmac_priv *priv)
+static void sun8i_dwmac_exit(struct platform_device *pdev, void *priv)
 {
-	struct sunxi_priv_data *gmac = priv->plat->bsp_priv;
-	int ret;
-
-	if (!gmac->use_internal_phy)
-		return 0;
-
-	ret = clk_prepare_enable(gmac->ephy_clk);
-	if (ret) {
-		dev_err(priv->device, "Cannot enable ephy\n");
-		return ret;
-	}
-
-	/* Make sure the EPHY is properly reseted, as U-Boot may leave
-	 * it at deasserted state, and thus it may fail to reset EMAC.
-	 */
-	reset_control_assert(gmac->rst_ephy);
+	struct sunxi_priv_data *gmac = priv;
 
-	ret = reset_control_deassert(gmac->rst_ephy);
-	if (ret) {
-		dev_err(priv->device, "Cannot deassert ephy\n");
-		clk_disable_unprepare(gmac->ephy_clk);
-		return ret;
+	if (gmac->variant->soc_has_internal_phy) {
+		/* sun8i_dwmac_exit could be called with mdiomux uninit */
+		if (gmac->mux_handle)
+			mdio_mux_uninit(gmac->mux_handle);
+		if (gmac->internal_phy_powered)
+			sun8i_dwmac_unpower_internal_phy(gmac);
 	}
 
-	return 0;
-}
-
-static int sun8i_dwmac_unpower_internal_phy(struct sunxi_priv_data *gmac)
-{
-	if (!gmac->use_internal_phy)
-		return 0;
-
-	clk_disable_unprepare(gmac->ephy_clk);
-	reset_control_assert(gmac->rst_ephy);
-	return 0;
-}
-
-/* sun8i_power_phy() - Activate the PHY:
- * In case of error, no need to call sun8i_unpower_phy(),
- * it will be called anyway by sun8i_dwmac_exit()
- */
-static int sun8i_power_phy(struct stmmac_priv *priv)
-{
-	int ret;
-
-	ret = sun8i_dwmac_power_internal_phy(priv);
-	if (ret)
-		return ret;
-
-	ret = sun8i_dwmac_set_syscon(priv);
-	if (ret)
-		return ret;
-
-	/* After changing syscon value, the MAC need reset or it will use
-	 * the last value (and so the last PHY set.
-	 */
-	ret = sun8i_dwmac_reset(priv);
-	if (ret)
-		return ret;
-	return 0;
-}
-
-static void sun8i_unpower_phy(struct sunxi_priv_data *gmac)
-{
 	sun8i_dwmac_unset_syscon(gmac);
-	sun8i_dwmac_unpower_internal_phy(gmac);
-}
 
-static void sun8i_dwmac_exit(struct platform_device *pdev, void *priv)
-{
-	struct sunxi_priv_data *gmac = priv;
-
-	sun8i_unpower_phy(gmac);
+	reset_control_put(gmac->rst_ephy);
 
 	clk_disable_unprepare(gmac->tx_clk);
 
@@ -849,7 +942,7 @@ static struct mac_device_info *sun8i_dwmac_setup(void *ppriv)
 	if (!mac)
 		return NULL;
 
-	ret = sun8i_power_phy(priv);
+	ret = sun8i_dwmac_set_syscon(priv);
 	if (ret)
 		return NULL;
 
@@ -889,6 +982,8 @@ static int sun8i_dwmac_probe(struct platform_device *pdev)
 	struct sunxi_priv_data *gmac;
 	struct device *dev = &pdev->dev;
 	int ret;
+	struct stmmac_priv *priv;
+	struct net_device *ndev;
 
 	ret = stmmac_get_platform_resources(pdev, &stmmac_res);
 	if (ret)
@@ -932,29 +1027,6 @@ static int sun8i_dwmac_probe(struct platform_device *pdev)
 	}
 
 	plat_dat->interface = of_get_phy_mode(dev->of_node);
-	if (plat_dat->interface == gmac->variant->internal_phy) {
-		dev_info(&pdev->dev, "Will use internal PHY\n");
-		gmac->use_internal_phy = true;
-		gmac->ephy_clk = of_clk_get(plat_dat->phy_node, 0);
-		if (IS_ERR(gmac->ephy_clk)) {
-			ret = PTR_ERR(gmac->ephy_clk);
-			dev_err(&pdev->dev, "Cannot get EPHY clock: %d\n", ret);
-			return -EINVAL;
-		}
-
-		gmac->rst_ephy = of_reset_control_get(plat_dat->phy_node, NULL);
-		if (IS_ERR(gmac->rst_ephy)) {
-			ret = PTR_ERR(gmac->rst_ephy);
-			if (ret == -EPROBE_DEFER)
-				return ret;
-			dev_err(&pdev->dev, "No EPHY reset control found %d\n",
-				ret);
-			return -EINVAL;
-		}
-	} else {
-		dev_info(&pdev->dev, "Will use external PHY\n");
-		gmac->use_internal_phy = false;
-	}
 
 	/* platform data specifying hardware features and callbacks.
 	 * hardware features were copied from Allwinner drivers.
@@ -973,9 +1045,34 @@ static int sun8i_dwmac_probe(struct platform_device *pdev)
 
 	ret = stmmac_dvr_probe(&pdev->dev, plat_dat, &stmmac_res);
 	if (ret)
-		sun8i_dwmac_exit(pdev, plat_dat->bsp_priv);
+		goto dwmac_exit;
+
+	ndev = dev_get_drvdata(&pdev->dev);
+	priv = netdev_priv(ndev);
+	/* The mux must be registered after parent MDIO
+	 * so after stmmac_dvr_probe()
+	 */
+	if (gmac->variant->soc_has_internal_phy) {
+		ret = get_ephy_nodes(priv);
+		if (ret)
+			return ret;
+		ret = sun8i_dwmac_register_mdio_mux(priv);
+		if (ret) {
+			dev_err(&pdev->dev, "Failed to register mux\n");
+			goto dwmac_mux;
+		}
+	} else {
+		ret = sun8i_dwmac_reset(priv);
+		if (ret)
+			goto dwmac_exit;
+	}
 
 	return ret;
+dwmac_mux:
+	sun8i_dwmac_unset_syscon(gmac);
+dwmac_exit:
+	sun8i_dwmac_exit(pdev, plat_dat->bsp_priv);
+return ret;
 }
 
 static const struct of_device_id sun8i_dwmac_match[] = {
-- 
2.13.6