net: bcmgenet: add MDIO routines

This patch adds support for configuring the port multiplexer hardware
which resides in front of the GENET Ethernet MAC controller. This allows
us to support:

- internal PHYs (using drivers/net/phy/bcm7xxx.c)
- MoCA PHYs which are an entirely separate hardware block not covered
  here
- external PHYs and switches

Note that MoCA and switches are currently supported using the emulated
"fixed PHY" driver.
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/broadcom/genet/bcmmii.c

+/*
+ * Broadcom GENET MDIO routines
+ *
+ * Copyright (c) 2014 Broadcom Corporation
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+ */
+
+
+#include <linux/types.h>
+#include <linux/delay.h>
+#include <linux/wait.h>
+#include <linux/mii.h>
+#include <linux/ethtool.h>
+#include <linux/bitops.h>
+#include <linux/netdevice.h>
+#include <linux/platform_device.h>
+#include <linux/phy.h>
+#include <linux/phy_fixed.h>
+#include <linux/brcmphy.h>
+#include <linux/of.h>
+#include <linux/of_net.h>
+#include <linux/of_mdio.h>
+
+#include "bcmgenet.h"
+
+/* read a value from the MII */
+static int bcmgenet_mii_read(struct mii_bus *bus, int phy_id, int location)
+{
+	int ret;
+	struct net_device *dev = bus->priv;
+	struct bcmgenet_priv *priv = netdev_priv(dev);
+	u32 reg;
+
+	bcmgenet_umac_writel(priv, (MDIO_RD | (phy_id << MDIO_PMD_SHIFT) |
+			(location << MDIO_REG_SHIFT)), UMAC_MDIO_CMD);
+	/* Start MDIO transaction*/
+	reg = bcmgenet_umac_readl(priv, UMAC_MDIO_CMD);
+	reg |= MDIO_START_BUSY;
+	bcmgenet_umac_writel(priv, reg, UMAC_MDIO_CMD);
+	wait_event_timeout(priv->wq,
+			!(bcmgenet_umac_readl(priv, UMAC_MDIO_CMD)
+				& MDIO_START_BUSY),
+			HZ / 100);
+	ret = bcmgenet_umac_readl(priv, UMAC_MDIO_CMD);
+
+	if (ret & MDIO_READ_FAIL)
+		return -EIO;
+
+	return ret & 0xffff;
+}
+
+/* write a value to the MII */
+static int bcmgenet_mii_write(struct mii_bus *bus, int phy_id,
+			int location, u16 val)
+{
+	struct net_device *dev = bus->priv;
+	struct bcmgenet_priv *priv = netdev_priv(dev);
+	u32 reg;
+
+	bcmgenet_umac_writel(priv, (MDIO_WR | (phy_id << MDIO_PMD_SHIFT) |
+			(location << MDIO_REG_SHIFT) | (0xffff & val)),
+			UMAC_MDIO_CMD);
+	reg = bcmgenet_umac_readl(priv, UMAC_MDIO_CMD);
+	reg |= MDIO_START_BUSY;
+	bcmgenet_umac_writel(priv, reg, UMAC_MDIO_CMD);
+	wait_event_timeout(priv->wq,
+			!(bcmgenet_umac_readl(priv, UMAC_MDIO_CMD) &
+				MDIO_START_BUSY),
+			HZ / 100);
+
+	return 0;
+}
+
+/* setup netdev link state when PHY link status change and
+ * update UMAC and RGMII block when link up
+ */
+static void bcmgenet_mii_setup(struct net_device *dev)
+{
+	struct bcmgenet_priv *priv = netdev_priv(dev);
+	struct phy_device *phydev = priv->phydev;
+	u32 reg, cmd_bits = 0;
+	unsigned int status_changed = 0;
+
+	if (priv->old_link != phydev->link) {
+		status_changed = 1;
+		priv->old_link = phydev->link;
+	}
+
+	if (phydev->link) {
+		/* program UMAC and RGMII block based on established link
+		 * speed, pause, and duplex.
+		 * the speed set in umac->cmd tell RGMII block which clock
+		 * 25MHz(100Mbps)/125MHz(1Gbps) to use for transmit.
+		 * receive clock is provided by PHY.
+		 */
+		reg = bcmgenet_ext_readl(priv, EXT_RGMII_OOB_CTRL);
+		reg &= ~OOB_DISABLE;
+		reg |= RGMII_LINK;
+		bcmgenet_ext_writel(priv, reg, EXT_RGMII_OOB_CTRL);
+
+		/* speed */
+		if (phydev->speed == SPEED_1000)
+			cmd_bits = UMAC_SPEED_1000;
+		else if (phydev->speed == SPEED_100)
+			cmd_bits = UMAC_SPEED_100;
+		else
+			cmd_bits = UMAC_SPEED_10;
+		cmd_bits <<= CMD_SPEED_SHIFT;
+
+		if (priv->old_duplex != phydev->duplex) {
+			status_changed = 1;
+			priv->old_duplex = phydev->duplex;
+		}
+
+		/* duplex */
+		if (phydev->duplex != DUPLEX_FULL)
+			cmd_bits |= CMD_HD_EN;
+
+		if (priv->old_pause != phydev->pause) {
+			status_changed = 1;
+			priv->old_pause = phydev->pause;
+		}
+
+		/* pause capability */
+		if (!phydev->pause)
+			cmd_bits |= CMD_RX_PAUSE_IGNORE | CMD_TX_PAUSE_IGNORE;
+
+		reg = bcmgenet_umac_readl(priv, UMAC_CMD);
+		reg &= ~((CMD_SPEED_MASK << CMD_SPEED_SHIFT) |
+			       CMD_HD_EN |
+			       CMD_RX_PAUSE_IGNORE | CMD_TX_PAUSE_IGNORE);
+		reg |= cmd_bits;
+		bcmgenet_umac_writel(priv, reg, UMAC_CMD);
+	}
+
+	if (status_changed)
+		phy_print_status(phydev);
+}
+
+void bcmgenet_mii_reset(struct net_device *dev)
+{
+	struct bcmgenet_priv *priv = netdev_priv(dev);
+
+	if (priv->phydev) {
+		phy_init_hw(priv->phydev);
+		phy_start_aneg(priv->phydev);
+	}
+}
+
+static void bcmgenet_ephy_power_up(struct net_device *dev)
+{
+	struct bcmgenet_priv *priv = netdev_priv(dev);
+	u32 reg = 0;
+
+	/* EXT_GPHY_CTRL is only valid for GENETv4 and onward */
+	if (!GENET_IS_V4(priv))
+		return;
+
+	reg = bcmgenet_ext_readl(priv, EXT_GPHY_CTRL);
+	reg &= ~(EXT_CFG_IDDQ_BIAS | EXT_CFG_PWR_DOWN);
+	reg |= EXT_GPHY_RESET;
+	bcmgenet_ext_writel(priv, reg, EXT_GPHY_CTRL);
+	mdelay(2);
+
+	reg &= ~EXT_GPHY_RESET;
+	bcmgenet_ext_writel(priv, reg, EXT_GPHY_CTRL);
+	udelay(20);
+}
+
+static void bcmgenet_internal_phy_setup(struct net_device *dev)
+{
+	struct bcmgenet_priv *priv = netdev_priv(dev);
+	u32 reg;
+
+	/* Power up EPHY */
+	bcmgenet_ephy_power_up(dev);
+	/* enable APD */
+	reg = bcmgenet_ext_readl(priv, EXT_EXT_PWR_MGMT);
+	reg |= EXT_PWR_DN_EN_LD;
+	bcmgenet_ext_writel(priv, reg, EXT_EXT_PWR_MGMT);
+	bcmgenet_mii_reset(dev);
+}
+
+static void bcmgenet_moca_phy_setup(struct bcmgenet_priv *priv)
+{
+	u32 reg;
+
+	/* Speed settings are set in bcmgenet_mii_setup() */
+	reg = bcmgenet_sys_readl(priv, SYS_PORT_CTRL);
+	reg |= LED_ACT_SOURCE_MAC;
+	bcmgenet_sys_writel(priv, reg, SYS_PORT_CTRL);
+}
+
+int bcmgenet_mii_config(struct net_device *dev)
+{
+	struct bcmgenet_priv *priv = netdev_priv(dev);
+	struct phy_device *phydev = priv->phydev;
+	struct device *kdev = &priv->pdev->dev;
+	const char *phy_name = NULL;
+	u32 id_mode_dis = 0;
+	u32 port_ctrl;
+	u32 reg;
+
+	priv->ext_phy = !phy_is_internal(priv->phydev) &&
+			(priv->phy_interface != PHY_INTERFACE_MODE_MOCA);
+
+	if (phy_is_internal(priv->phydev))
+		priv->phy_interface = PHY_INTERFACE_MODE_NA;
+
+	switch (priv->phy_interface) {
+	case PHY_INTERFACE_MODE_NA:
+	case PHY_INTERFACE_MODE_MOCA:
+		/* Irrespective of the actually configured PHY speed (100 or
+		 * 1000) GENETv4 only has an internal GPHY so we will just end
+		 * up masking the Gigabit features from what we support, not
+		 * switching to the EPHY
+		 */
+		if (GENET_IS_V4(priv))
+			port_ctrl = PORT_MODE_INT_GPHY;
+		else
+			port_ctrl = PORT_MODE_INT_EPHY;
+
+		bcmgenet_sys_writel(priv, port_ctrl, SYS_PORT_CTRL);
+
+		if (phy_is_internal(priv->phydev)) {
+			phy_name = "internal PHY";
+			bcmgenet_internal_phy_setup(dev);
+		} else if (priv->phy_interface == PHY_INTERFACE_MODE_MOCA) {
+			phy_name = "MoCA";
+			bcmgenet_moca_phy_setup(priv);
+		}
+		break;
+
+	case PHY_INTERFACE_MODE_MII:
+		phy_name = "external MII";
+		phydev->supported &= PHY_BASIC_FEATURES;
+		bcmgenet_sys_writel(priv,
+				PORT_MODE_EXT_EPHY, SYS_PORT_CTRL);
+		break;
+
+	case PHY_INTERFACE_MODE_REVMII:
+		phy_name = "external RvMII";
+		/* of_mdiobus_register took care of reading the 'max-speed'
+		 * PHY property for us, effectively limiting the PHY supported
+		 * capabilities, use that knowledge to also configure the
+		 * Reverse MII interface correctly.
+		 */
+		if ((priv->phydev->supported & PHY_BASIC_FEATURES) ==
+				PHY_BASIC_FEATURES)
+			port_ctrl = PORT_MODE_EXT_RVMII_25;
+		else
+			port_ctrl = PORT_MODE_EXT_RVMII_50;
+		bcmgenet_sys_writel(priv, port_ctrl, SYS_PORT_CTRL);
+		break;
+
+	case PHY_INTERFACE_MODE_RGMII:
+		/* RGMII_NO_ID: TXC transitions at the same time as TXD
+		 *		(requires PCB or receiver-side delay)
+		 * RGMII:	Add 2ns delay on TXC (90 degree shift)
+		 *
+		 * ID is implicitly disabled for 100Mbps (RG)MII operation.
+		 */
+		id_mode_dis = BIT(16);
+		/* fall through */
+	case PHY_INTERFACE_MODE_RGMII_TXID:
+		if (id_mode_dis)
+			phy_name = "external RGMII (no delay)";
+		else
+			phy_name = "external RGMII (TX delay)";
+		reg = bcmgenet_ext_readl(priv, EXT_RGMII_OOB_CTRL);
+		reg |= RGMII_MODE_EN | id_mode_dis;
+		bcmgenet_ext_writel(priv, reg, EXT_RGMII_OOB_CTRL);
+		bcmgenet_sys_writel(priv,
+				PORT_MODE_EXT_GPHY, SYS_PORT_CTRL);
+		break;
+	default:
+		dev_err(kdev, "unknown phy mode: %d\n", priv->phy_interface);
+		return -EINVAL;
+	}
+
+	dev_info(kdev, "configuring instance for %s\n", phy_name);
+
+	return 0;
+}
+
+static int bcmgenet_mii_probe(struct net_device *dev)
+{
+	struct bcmgenet_priv *priv = netdev_priv(dev);
+	struct phy_device *phydev;
+	unsigned int phy_flags;
+	int ret;
+
+	if (priv->phydev) {
+		pr_info("PHY already attached\n");
+		return 0;
+	}
+
+	if (priv->phy_dn)
+		phydev = of_phy_connect(dev, priv->phy_dn,
+					bcmgenet_mii_setup, 0,
+					priv->phy_interface);
+	else
+		phydev = of_phy_connect_fixed_link(dev,
+					bcmgenet_mii_setup,
+					priv->phy_interface);
+
+	if (!phydev) {
+		pr_err("could not attach to PHY\n");
+		return -ENODEV;
+	}
+
+	priv->old_link = -1;
+	priv->old_duplex = -1;
+	priv->old_pause = -1;
+	priv->phydev = phydev;
+
+	/* Configure port multiplexer based on what the probed PHY device since
+	 * reading the 'max-speed' property determines the maximum supported
+	 * PHY speed which is needed for bcmgenet_mii_config() to configure
+	 * things appropriately.
+	 */
+	ret = bcmgenet_mii_config(dev);
+	if (ret) {
+		phy_disconnect(priv->phydev);
+		return ret;
+	}
+
+	phy_flags = PHY_BRCM_100MBPS_WAR;
+
+	/* workarounds are only needed for 100Mpbs PHYs, and
+	 * never on GENET V1 hardware
+	 */
+	if ((phydev->supported & PHY_GBIT_FEATURES) || GENET_IS_V1(priv))
+		phy_flags = 0;
+
+	phydev->dev_flags |= phy_flags;
+	phydev->advertising = phydev->supported;
+
+	/* The internal PHY has its link interrupts routed to the
+	 * Ethernet MAC ISRs
+	 */
+	if (phy_is_internal(priv->phydev))
+		priv->mii_bus->irq[phydev->addr] = PHY_IGNORE_INTERRUPT;
+	else
+		priv->mii_bus->irq[phydev->addr] = PHY_POLL;
+
+	pr_info("attached PHY at address %d [%s]\n",
+			phydev->addr, phydev->drv->name);
+
+	return 0;
+}
+
+static int bcmgenet_mii_alloc(struct bcmgenet_priv *priv)
+{
+	struct mii_bus *bus;
+
+	if (priv->mii_bus)
+		return 0;
+
+	priv->mii_bus = mdiobus_alloc();
+	if (!priv->mii_bus) {
+		pr_err("failed to allocate\n");
+		return -ENOMEM;
+	}
+
+	bus = priv->mii_bus;
+	bus->priv = priv->dev;
+	bus->name = "bcmgenet MII bus";
+	bus->parent = &priv->pdev->dev;
+	bus->read = bcmgenet_mii_read;
+	bus->write = bcmgenet_mii_write;
+	snprintf(bus->id, MII_BUS_ID_SIZE, "%s-%d",
+			priv->pdev->name, priv->pdev->id);
+
+	bus->irq = kzalloc(sizeof(int) * PHY_MAX_ADDR, GFP_KERNEL);
+	if (!bus->irq) {
+		mdiobus_free(priv->mii_bus);
+		return -ENOMEM;
+	}
+
+	return 0;
+}
+
+static int bcmgenet_mii_of_init(struct bcmgenet_priv *priv)
+{
+	struct device_node *dn = priv->pdev->dev.of_node;
+	struct device *kdev = &priv->pdev->dev;
+	struct device_node *mdio_dn;
+	char *compat;
+	int ret;
+
+	compat = kasprintf(GFP_KERNEL, "brcm,genet-mdio-v%d", priv->version);
+	if (!compat)
+		return -ENOMEM;
+
+	mdio_dn = of_find_compatible_node(dn, NULL, compat);
+	kfree(compat);
+	if (!mdio_dn) {
+		dev_err(kdev, "unable to find MDIO bus node\n");
+		return -ENODEV;
+	}
+
+	ret = of_mdiobus_register(priv->mii_bus, mdio_dn);
+	if (ret) {
+		dev_err(kdev, "failed to register MDIO bus\n");
+		return ret;
+	}
+
+	/* Fetch the PHY phandle */
+	priv->phy_dn = of_parse_phandle(dn, "phy-handle", 0);
+
+	/* Get the link mode */
+	priv->phy_interface = of_get_phy_mode(dn);
+
+	return 0;
+}
+
+int bcmgenet_mii_init(struct net_device *dev)
+{
+	struct bcmgenet_priv *priv = netdev_priv(dev);
+	int ret;
+
+	ret = bcmgenet_mii_alloc(priv);
+	if (ret)
+		return ret;
+
+	ret = bcmgenet_mii_of_init(priv);
+	if (ret)
+		goto out_free;
+
+	ret = bcmgenet_mii_probe(dev);
+	if (ret)
+		goto out;
+
+	return 0;
+
+out:
+	mdiobus_unregister(priv->mii_bus);
+out_free:
+	kfree(priv->mii_bus->irq);
+	mdiobus_free(priv->mii_bus);
+	return ret;
+}
+
+void bcmgenet_mii_exit(struct net_device *dev)
+{
+	struct bcmgenet_priv *priv = netdev_priv(dev);
+
+	mdiobus_unregister(priv->mii_bus);
+	kfree(priv->mii_bus->irq);
+	mdiobus_free(priv->mii_bus);
+}