drivers/net/ethernet/freescale/xgmac_mdio.c - linux - Git at Google

 /*
  * QorIQ 10G MDIO Controller
  *
  * Copyright 2012 Freescale Semiconductor, Inc.
  * Copyright 2021 NXP
  *
  * Authors: Andy Fleming <afleming@freescale.com>
  *          Timur Tabi <timur@freescale.com>
  *
  * This file is licensed under the terms of the GNU General Public License
  * version 2.  This program is licensed "as is" without any warranty of any
  * kind, whether express or implied.
  */

 #include <linux/acpi.h>
 #include <linux/acpi_mdio.h>
 #include <linux/clk.h>
 #include <linux/interrupt.h>
 #include <linux/kernel.h>
 #include <linux/mdio.h>
 #include <linux/module.h>
 #include <linux/of_address.h>
 #include <linux/of_mdio.h>
 #include <linux/of_platform.h>
 #include <linux/phy.h>
 #include <linux/slab.h>

 /* Number of microseconds to wait for a register to respond */
 #define TIMEOUT	1000

 struct tgec_mdio_controller {
 	__be32	reserved[12];
 	__be32	mdio_stat;	/* MDIO configuration and status */
 	__be32	mdio_ctl;	/* MDIO control */
 	__be32	mdio_data;	/* MDIO data */
 	__be32	mdio_addr;	/* MDIO address */
 } __packed;

 #define MDIO_STAT_ENC		BIT(6)
 #define MDIO_STAT_CLKDIV(x)	(((x) & 0x1ff) << 7)
 #define MDIO_STAT_BSY		BIT(0)
 #define MDIO_STAT_RD_ER		BIT(1)
 #define MDIO_STAT_PRE_DIS	BIT(5)
 #define MDIO_CTL_DEV_ADDR(x) 	(x & 0x1f)
 #define MDIO_CTL_PORT_ADDR(x)	((x & 0x1f) << 5)
 #define MDIO_CTL_PRE_DIS	BIT(10)
 #define MDIO_CTL_SCAN_EN	BIT(11)
 #define MDIO_CTL_POST_INC	BIT(14)
 #define MDIO_CTL_READ		BIT(15)

 #define MDIO_DATA(x)		(x & 0xffff)

 struct mdio_fsl_priv {
 	struct	tgec_mdio_controller __iomem *mdio_base;
 	struct	clk *enet_clk;
 	u32	mdc_freq;
 	bool	is_little_endian;
 	bool	has_a009885;
 	bool	has_a011043;
 };

 static u32 xgmac_read32(void __iomem *regs,
 			bool is_little_endian)
 {
 	if (is_little_endian)
 		return ioread32(regs);
 	else
 		return ioread32be(regs);
 }

 static void xgmac_write32(u32 value,
 			  void __iomem *regs,
 			  bool is_little_endian)
 {
 	if (is_little_endian)
 		iowrite32(value, regs);
 	else
 		iowrite32be(value, regs);
 }

 /*
  * Wait until the MDIO bus is free
  */
 static int xgmac_wait_until_free(struct device *dev,
 				 struct tgec_mdio_controller __iomem *regs,
 				 bool is_little_endian)
 {
 	unsigned int timeout;

 	/* Wait till the bus is free */
 	timeout = TIMEOUT;
 	while ((xgmac_read32(&regs->mdio_stat, is_little_endian) &
 		MDIO_STAT_BSY) && timeout) {
 		cpu_relax();
 		timeout--;
 	}

 	if (!timeout) {
 		dev_err(dev, "timeout waiting for bus to be free\n");
 		return -ETIMEDOUT;
 	}

 	return 0;
 }

 /*
  * Wait till the MDIO read or write operation is complete
  */
 static int xgmac_wait_until_done(struct device *dev,
 				 struct tgec_mdio_controller __iomem *regs,
 				 bool is_little_endian)
 {
 	unsigned int timeout;

 	/* Wait till the MDIO write is complete */
 	timeout = TIMEOUT;
 	while ((xgmac_read32(&regs->mdio_stat, is_little_endian) &
 		MDIO_STAT_BSY) && timeout) {
 		cpu_relax();
 		timeout--;
 	}

 	if (!timeout) {
 		dev_err(dev, "timeout waiting for operation to complete\n");
 		return -ETIMEDOUT;
 	}

 	return 0;
 }

 /*
  * Write value to the PHY for this device to the register at regnum,waiting
  * until the write is done before it returns.  All PHY configuration has to be
  * done through the TSEC1 MIIM regs.
  */
 static int xgmac_mdio_write(struct mii_bus *bus, int phy_id, int regnum, u16 value)
 {
 	struct mdio_fsl_priv *priv = (struct mdio_fsl_priv *)bus->priv;
 	struct tgec_mdio_controller __iomem *regs = priv->mdio_base;
 	uint16_t dev_addr;
 	u32 mdio_ctl, mdio_stat;
 	int ret;
 	bool endian = priv->is_little_endian;

 	mdio_stat = xgmac_read32(&regs->mdio_stat, endian);
 	if (regnum & MII_ADDR_C45) {
 		/* Clause 45 (ie 10G) */
 		dev_addr = (regnum >> 16) & 0x1f;
 		mdio_stat |= MDIO_STAT_ENC;
 	} else {
 		/* Clause 22 (ie 1G) */
 		dev_addr = regnum & 0x1f;
 		mdio_stat &= ~MDIO_STAT_ENC;
 	}

 	xgmac_write32(mdio_stat, &regs->mdio_stat, endian);

 	ret = xgmac_wait_until_free(&bus->dev, regs, endian);
 	if (ret)
 		return ret;

 	/* Set the port and dev addr */
 	mdio_ctl = MDIO_CTL_PORT_ADDR(phy_id) | MDIO_CTL_DEV_ADDR(dev_addr);
 	xgmac_write32(mdio_ctl, &regs->mdio_ctl, endian);

 	/* Set the register address */
 	if (regnum & MII_ADDR_C45) {
 		xgmac_write32(regnum & 0xffff, &regs->mdio_addr, endian);

 		ret = xgmac_wait_until_free(&bus->dev, regs, endian);
 		if (ret)
 			return ret;
 	}

 	/* Write the value to the register */
 	xgmac_write32(MDIO_DATA(value), &regs->mdio_data, endian);

 	ret = xgmac_wait_until_done(&bus->dev, regs, endian);
 	if (ret)
 		return ret;

 	return 0;
 }

 /*
  * Reads from register regnum in the PHY for device dev, returning the value.
  * Clears miimcom first.  All PHY configuration has to be done through the
  * TSEC1 MIIM regs.
  */
 static int xgmac_mdio_read(struct mii_bus *bus, int phy_id, int regnum)
 {
 	struct mdio_fsl_priv *priv = (struct mdio_fsl_priv *)bus->priv;
 	struct tgec_mdio_controller __iomem *regs = priv->mdio_base;
 	unsigned long flags;
 	uint16_t dev_addr;
 	uint32_t mdio_stat;
 	uint32_t mdio_ctl;
 	int ret;
 	bool endian = priv->is_little_endian;

 	mdio_stat = xgmac_read32(&regs->mdio_stat, endian);
 	if (regnum & MII_ADDR_C45) {
 		dev_addr = (regnum >> 16) & 0x1f;
 		mdio_stat |= MDIO_STAT_ENC;
 	} else {
 		dev_addr = regnum & 0x1f;
 		mdio_stat &= ~MDIO_STAT_ENC;
 	}

 	xgmac_write32(mdio_stat, &regs->mdio_stat, endian);

 	ret = xgmac_wait_until_free(&bus->dev, regs, endian);
 	if (ret)
 		return ret;

 	/* Set the Port and Device Addrs */
 	mdio_ctl = MDIO_CTL_PORT_ADDR(phy_id) | MDIO_CTL_DEV_ADDR(dev_addr);
 	xgmac_write32(mdio_ctl, &regs->mdio_ctl, endian);

 	/* Set the register address */
 	if (regnum & MII_ADDR_C45) {
 		xgmac_write32(regnum & 0xffff, &regs->mdio_addr, endian);

 		ret = xgmac_wait_until_free(&bus->dev, regs, endian);
 		if (ret)
 			return ret;
 	}

 	if (priv->has_a009885)
 		/* Once the operation completes, i.e. MDIO_STAT_BSY clears, we
 		 * must read back the data register within 16 MDC cycles.
 		 */
 		local_irq_save(flags);

 	/* Initiate the read */
 	xgmac_write32(mdio_ctl | MDIO_CTL_READ, &regs->mdio_ctl, endian);

 	ret = xgmac_wait_until_done(&bus->dev, regs, endian);
 	if (ret)
 		goto irq_restore;

 	/* Return all Fs if nothing was there */
 	if ((xgmac_read32(&regs->mdio_stat, endian) & MDIO_STAT_RD_ER) &&
 	    !priv->has_a011043) {
 		dev_dbg(&bus->dev,
 			"Error while reading PHY%d reg at %d.%d\n",
 			phy_id, dev_addr, regnum);
 		ret = 0xffff;
 	} else {
 		ret = xgmac_read32(&regs->mdio_data, endian) & 0xffff;
 		dev_dbg(&bus->dev, "read %04x\n", ret);
 	}

 irq_restore:
 	if (priv->has_a009885)
 		local_irq_restore(flags);

 	return ret;
 }

 static int xgmac_mdio_set_mdc_freq(struct mii_bus *bus)
 {
 	struct mdio_fsl_priv *priv = (struct mdio_fsl_priv *)bus->priv;
 	struct tgec_mdio_controller __iomem *regs = priv->mdio_base;
 	struct device *dev = bus->parent;
 	u32 mdio_stat, div;

 	if (device_property_read_u32(dev, "clock-frequency", &priv->mdc_freq))
 		return 0;

 	priv->enet_clk = devm_clk_get(dev, NULL);
 	if (IS_ERR(priv->enet_clk)) {
 		dev_err(dev, "Input clock unknown, not changing MDC frequency");
 		return PTR_ERR(priv->enet_clk);
 	}

 	div = ((clk_get_rate(priv->enet_clk) / priv->mdc_freq) - 1) / 2;
 	if (div < 5 || div > 0x1ff) {
 		dev_err(dev, "Requested MDC frequency is out of range, ignoring");
 		return -EINVAL;
 	}

 	mdio_stat = xgmac_read32(&regs->mdio_stat, priv->is_little_endian);
 	mdio_stat &= ~MDIO_STAT_CLKDIV(0x1ff);
 	mdio_stat |= MDIO_STAT_CLKDIV(div);
 	xgmac_write32(mdio_stat, &regs->mdio_stat, priv->is_little_endian);
 	return 0;
 }

 static void xgmac_mdio_set_suppress_preamble(struct mii_bus *bus)
 {
 	struct mdio_fsl_priv *priv = (struct mdio_fsl_priv *)bus->priv;
 	struct tgec_mdio_controller __iomem *regs = priv->mdio_base;
 	struct device *dev = bus->parent;
 	u32 mdio_stat;

 	if (!device_property_read_bool(dev, "suppress-preamble"))
 		return;

 	mdio_stat = xgmac_read32(&regs->mdio_stat, priv->is_little_endian);
 	mdio_stat |= MDIO_STAT_PRE_DIS;
 	xgmac_write32(mdio_stat, &regs->mdio_stat, priv->is_little_endian);
 }

 static int xgmac_mdio_probe(struct platform_device *pdev)
 {
 	struct fwnode_handle *fwnode;
 	struct mdio_fsl_priv *priv;
 	struct resource *res;
 	struct mii_bus *bus;
 	int ret;

 	/* In DPAA-1, MDIO is one of the many FMan sub-devices. The FMan
 	 * defines a register space that spans a large area, covering all the
 	 * subdevice areas. Therefore, MDIO cannot claim exclusive access to
 	 * this register area.
 	 */
 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 	if (!res) {
 		dev_err(&pdev->dev, "could not obtain address\n");
 		return -EINVAL;
 	}

 	bus = devm_mdiobus_alloc_size(&pdev->dev, sizeof(struct mdio_fsl_priv));
 	if (!bus)
 		return -ENOMEM;

 	bus->name = "Freescale XGMAC MDIO Bus";
 	bus->read = xgmac_mdio_read;
 	bus->write = xgmac_mdio_write;
 	bus->parent = &pdev->dev;
 	bus->probe_capabilities = MDIOBUS_C22_C45;
 	snprintf(bus->id, MII_BUS_ID_SIZE, "%pa", &res->start);

 	priv = bus->priv;
 	priv->mdio_base = devm_ioremap(&pdev->dev, res->start,
 				       resource_size(res));
 	if (!priv->mdio_base)
 		return -ENOMEM;

 	/* For both ACPI and DT cases, endianness of MDIO controller
 	 * needs to be specified using "little-endian" property.
 	 */
 	priv->is_little_endian = device_property_read_bool(&pdev->dev,
 							   "little-endian");

 	priv->has_a009885 = device_property_read_bool(&pdev->dev,
 						      "fsl,erratum-a009885");
 	priv->has_a011043 = device_property_read_bool(&pdev->dev,
 						      "fsl,erratum-a011043");

 	xgmac_mdio_set_suppress_preamble(bus);

 	ret = xgmac_mdio_set_mdc_freq(bus);
 	if (ret)
 		return ret;

 	fwnode = dev_fwnode(&pdev->dev);
 	if (is_of_node(fwnode))
 		ret = of_mdiobus_register(bus, to_of_node(fwnode));
 	else if (is_acpi_node(fwnode))
 		ret = acpi_mdiobus_register(bus, fwnode);
 	else
 		ret = -EINVAL;
 	if (ret) {
 		dev_err(&pdev->dev, "cannot register MDIO bus\n");
 		return ret;
 	}

 	platform_set_drvdata(pdev, bus);

 	return 0;
 }

 static const struct of_device_id xgmac_mdio_match[] = {
 	{
 		.compatible = "fsl,fman-xmdio",
 	},
 	{
 		.compatible = "fsl,fman-memac-mdio",
 	},
 	{},
 };
 MODULE_DEVICE_TABLE(of, xgmac_mdio_match);

 static const struct acpi_device_id xgmac_acpi_match[] = {
 	{ "NXP0006" },
 	{ }
 };
 MODULE_DEVICE_TABLE(acpi, xgmac_acpi_match);

 static struct platform_driver xgmac_mdio_driver = {
 	.driver = {
 		.name = "fsl-fman_xmdio",
 		.of_match_table = xgmac_mdio_match,
 		.acpi_match_table = xgmac_acpi_match,
 	},
 	.probe = xgmac_mdio_probe,
 };

 module_platform_driver(xgmac_mdio_driver);

 MODULE_DESCRIPTION("Freescale QorIQ 10G MDIO Controller");
 MODULE_LICENSE("GPL v2");
	/*
	* QorIQ 10G MDIO Controller
	*
	* Copyright 2012 Freescale Semiconductor, Inc.
	* Copyright 2021 NXP
	*
	* Authors: Andy Fleming <afleming@freescale.com>
	* Timur Tabi <timur@freescale.com>
	*
	* This file is licensed under the terms of the GNU General Public License
	* version 2. This program is licensed "as is" without any warranty of any
	* kind, whether express or implied.
	*/

	#include <linux/acpi.h>
	#include <linux/acpi_mdio.h>
	#include <linux/clk.h>
	#include <linux/interrupt.h>
	#include <linux/kernel.h>
	#include <linux/mdio.h>
	#include <linux/module.h>
	#include <linux/of_address.h>
	#include <linux/of_mdio.h>
	#include <linux/of_platform.h>
	#include <linux/phy.h>
	#include <linux/slab.h>

	/* Number of microseconds to wait for a register to respond */
	#define TIMEOUT 1000

	struct tgec_mdio_controller {
	__be32 reserved[12];
	__be32 mdio_stat; /* MDIO configuration and status */
	__be32 mdio_ctl; /* MDIO control */
	__be32 mdio_data; /* MDIO data */
	__be32 mdio_addr; /* MDIO address */
	} __packed;

	#define MDIO_STAT_ENC BIT(6)
	#define MDIO_STAT_CLKDIV(x) (((x) & 0x1ff) << 7)
	#define MDIO_STAT_BSY BIT(0)
	#define MDIO_STAT_RD_ER BIT(1)
	#define MDIO_STAT_PRE_DIS BIT(5)
	#define MDIO_CTL_DEV_ADDR(x) (x & 0x1f)
	#define MDIO_CTL_PORT_ADDR(x) ((x & 0x1f) << 5)
	#define MDIO_CTL_PRE_DIS BIT(10)
	#define MDIO_CTL_SCAN_EN BIT(11)
	#define MDIO_CTL_POST_INC BIT(14)
	#define MDIO_CTL_READ BIT(15)

	#define MDIO_DATA(x) (x & 0xffff)

	struct mdio_fsl_priv {
	struct tgec_mdio_controller __iomem *mdio_base;
	struct clk *enet_clk;
	u32 mdc_freq;
	bool is_little_endian;
	bool has_a009885;
	bool has_a011043;
	};

	static u32 xgmac_read32(void __iomem *regs,
	bool is_little_endian)
	{
	if (is_little_endian)
	return ioread32(regs);
	else
	return ioread32be(regs);
	}

	static void xgmac_write32(u32 value,
	void __iomem *regs,
	bool is_little_endian)
	{
	if (is_little_endian)
	iowrite32(value, regs);
	else
	iowrite32be(value, regs);
	}

	/*
	* Wait until the MDIO bus is free
	*/
	static int xgmac_wait_until_free(struct device *dev,
	struct tgec_mdio_controller __iomem *regs,
	bool is_little_endian)
	{
	unsigned int timeout;

	/* Wait till the bus is free */
	timeout = TIMEOUT;
	while ((xgmac_read32(&regs->mdio_stat, is_little_endian) &
	MDIO_STAT_BSY) && timeout) {
	cpu_relax();
	timeout--;
	}

	if (!timeout) {
	dev_err(dev, "timeout waiting for bus to be free\n");
	return -ETIMEDOUT;
	}

	return 0;
	}

	/*
	* Wait till the MDIO read or write operation is complete
	*/
	static int xgmac_wait_until_done(struct device *dev,
	struct tgec_mdio_controller __iomem *regs,
	bool is_little_endian)
	{
	unsigned int timeout;

	/* Wait till the MDIO write is complete */
	timeout = TIMEOUT;
	while ((xgmac_read32(&regs->mdio_stat, is_little_endian) &
	MDIO_STAT_BSY) && timeout) {
	cpu_relax();
	timeout--;
	}

	if (!timeout) {
	dev_err(dev, "timeout waiting for operation to complete\n");
	return -ETIMEDOUT;
	}

	return 0;
	}

	/*
	* Write value to the PHY for this device to the register at regnum,waiting
	* until the write is done before it returns. All PHY configuration has to be
	* done through the TSEC1 MIIM regs.
	*/
	static int xgmac_mdio_write(struct mii_bus *bus, int phy_id, int regnum, u16 value)
	{
	struct mdio_fsl_priv priv = (struct mdio_fsl_priv )bus->priv;
	struct tgec_mdio_controller __iomem *regs = priv->mdio_base;
	uint16_t dev_addr;
	u32 mdio_ctl, mdio_stat;
	int ret;
	bool endian = priv->is_little_endian;

	mdio_stat = xgmac_read32(&regs->mdio_stat, endian);
	if (regnum & MII_ADDR_C45) {
	/* Clause 45 (ie 10G) */
	dev_addr = (regnum >> 16) & 0x1f;
	mdio_stat \|= MDIO_STAT_ENC;
	} else {
	/* Clause 22 (ie 1G) */
	dev_addr = regnum & 0x1f;
	mdio_stat &= ~MDIO_STAT_ENC;
	}

	xgmac_write32(mdio_stat, &regs->mdio_stat, endian);

	ret = xgmac_wait_until_free(&bus->dev, regs, endian);
	if (ret)
	return ret;

	/* Set the port and dev addr */
	mdio_ctl = MDIO_CTL_PORT_ADDR(phy_id) \| MDIO_CTL_DEV_ADDR(dev_addr);
	xgmac_write32(mdio_ctl, &regs->mdio_ctl, endian);

	/* Set the register address */
	if (regnum & MII_ADDR_C45) {
	xgmac_write32(regnum & 0xffff, &regs->mdio_addr, endian);

	ret = xgmac_wait_until_free(&bus->dev, regs, endian);
	if (ret)
	return ret;
	}

	/* Write the value to the register */
	xgmac_write32(MDIO_DATA(value), &regs->mdio_data, endian);

	ret = xgmac_wait_until_done(&bus->dev, regs, endian);
	if (ret)
	return ret;

	return 0;
	}

	/*
	* Reads from register regnum in the PHY for device dev, returning the value.
	* Clears miimcom first. All PHY configuration has to be done through the
	* TSEC1 MIIM regs.
	*/
	static int xgmac_mdio_read(struct mii_bus *bus, int phy_id, int regnum)
	{
	struct mdio_fsl_priv priv = (struct mdio_fsl_priv )bus->priv;
	struct tgec_mdio_controller __iomem *regs = priv->mdio_base;
	unsigned long flags;
	uint16_t dev_addr;
	uint32_t mdio_stat;
	uint32_t mdio_ctl;
	int ret;
	bool endian = priv->is_little_endian;

	mdio_stat = xgmac_read32(&regs->mdio_stat, endian);
	if (regnum & MII_ADDR_C45) {
	dev_addr = (regnum >> 16) & 0x1f;
	mdio_stat \|= MDIO_STAT_ENC;
	} else {
	dev_addr = regnum & 0x1f;
	mdio_stat &= ~MDIO_STAT_ENC;
	}

	xgmac_write32(mdio_stat, &regs->mdio_stat, endian);

	ret = xgmac_wait_until_free(&bus->dev, regs, endian);
	if (ret)
	return ret;

	/* Set the Port and Device Addrs */
	mdio_ctl = MDIO_CTL_PORT_ADDR(phy_id) \| MDIO_CTL_DEV_ADDR(dev_addr);
	xgmac_write32(mdio_ctl, &regs->mdio_ctl, endian);

	/* Set the register address */
	if (regnum & MII_ADDR_C45) {
	xgmac_write32(regnum & 0xffff, &regs->mdio_addr, endian);

	ret = xgmac_wait_until_free(&bus->dev, regs, endian);
	if (ret)
	return ret;
	}

	if (priv->has_a009885)
	/* Once the operation completes, i.e. MDIO_STAT_BSY clears, we
	* must read back the data register within 16 MDC cycles.
	*/
	local_irq_save(flags);

	/* Initiate the read */
	xgmac_write32(mdio_ctl \| MDIO_CTL_READ, &regs->mdio_ctl, endian);

	ret = xgmac_wait_until_done(&bus->dev, regs, endian);
	if (ret)
	goto irq_restore;

	/* Return all Fs if nothing was there */
	if ((xgmac_read32(&regs->mdio_stat, endian) & MDIO_STAT_RD_ER) &&
	!priv->has_a011043) {
	dev_dbg(&bus->dev,
	"Error while reading PHY%d reg at %d.%d\n",
	phy_id, dev_addr, regnum);
	ret = 0xffff;
	} else {
	ret = xgmac_read32(&regs->mdio_data, endian) & 0xffff;
	dev_dbg(&bus->dev, "read %04x\n", ret);
	}

	irq_restore:
	if (priv->has_a009885)
	local_irq_restore(flags);

	return ret;
	}

	static int xgmac_mdio_set_mdc_freq(struct mii_bus *bus)
	{
	struct mdio_fsl_priv priv = (struct mdio_fsl_priv )bus->priv;
	struct tgec_mdio_controller __iomem *regs = priv->mdio_base;
	struct device *dev = bus->parent;
	u32 mdio_stat, div;

	if (device_property_read_u32(dev, "clock-frequency", &priv->mdc_freq))
	return 0;

	priv->enet_clk = devm_clk_get(dev, NULL);
	if (IS_ERR(priv->enet_clk)) {
	dev_err(dev, "Input clock unknown, not changing MDC frequency");
	return PTR_ERR(priv->enet_clk);
	}

	div = ((clk_get_rate(priv->enet_clk) / priv->mdc_freq) - 1) / 2;
	if (div < 5 \|\| div > 0x1ff) {
	dev_err(dev, "Requested MDC frequency is out of range, ignoring");
	return -EINVAL;
	}

	mdio_stat = xgmac_read32(&regs->mdio_stat, priv->is_little_endian);
	mdio_stat &= ~MDIO_STAT_CLKDIV(0x1ff);
	mdio_stat \|= MDIO_STAT_CLKDIV(div);
	xgmac_write32(mdio_stat, &regs->mdio_stat, priv->is_little_endian);
	return 0;
	}

	static void xgmac_mdio_set_suppress_preamble(struct mii_bus *bus)
	{
	struct mdio_fsl_priv priv = (struct mdio_fsl_priv )bus->priv;
	struct tgec_mdio_controller __iomem *regs = priv->mdio_base;
	struct device *dev = bus->parent;
	u32 mdio_stat;

	if (!device_property_read_bool(dev, "suppress-preamble"))
	return;

	mdio_stat = xgmac_read32(&regs->mdio_stat, priv->is_little_endian);
	mdio_stat \|= MDIO_STAT_PRE_DIS;
	xgmac_write32(mdio_stat, &regs->mdio_stat, priv->is_little_endian);
	}

	static int xgmac_mdio_probe(struct platform_device *pdev)
	{
	struct fwnode_handle *fwnode;
	struct mdio_fsl_priv *priv;
	struct resource *res;
	struct mii_bus *bus;
	int ret;

	/* In DPAA-1, MDIO is one of the many FMan sub-devices. The FMan
	* defines a register space that spans a large area, covering all the
	* subdevice areas. Therefore, MDIO cannot claim exclusive access to
	* this register area.
	*/
	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	if (!res) {
	dev_err(&pdev->dev, "could not obtain address\n");
	return -EINVAL;
	}

	bus = devm_mdiobus_alloc_size(&pdev->dev, sizeof(struct mdio_fsl_priv));
	if (!bus)
	return -ENOMEM;

	bus->name = "Freescale XGMAC MDIO Bus";
	bus->read = xgmac_mdio_read;
	bus->write = xgmac_mdio_write;
	bus->parent = &pdev->dev;
	bus->probe_capabilities = MDIOBUS_C22_C45;
	snprintf(bus->id, MII_BUS_ID_SIZE, "%pa", &res->start);

	priv = bus->priv;
	priv->mdio_base = devm_ioremap(&pdev->dev, res->start,
	resource_size(res));
	if (!priv->mdio_base)
	return -ENOMEM;

	/* For both ACPI and DT cases, endianness of MDIO controller
	* needs to be specified using "little-endian" property.
	*/
	priv->is_little_endian = device_property_read_bool(&pdev->dev,
	"little-endian");

	priv->has_a009885 = device_property_read_bool(&pdev->dev,
	"fsl,erratum-a009885");
	priv->has_a011043 = device_property_read_bool(&pdev->dev,
	"fsl,erratum-a011043");

	xgmac_mdio_set_suppress_preamble(bus);

	ret = xgmac_mdio_set_mdc_freq(bus);
	if (ret)
	return ret;

	fwnode = dev_fwnode(&pdev->dev);
	if (is_of_node(fwnode))
	ret = of_mdiobus_register(bus, to_of_node(fwnode));
	else if (is_acpi_node(fwnode))
	ret = acpi_mdiobus_register(bus, fwnode);
	else
	ret = -EINVAL;
	if (ret) {
	dev_err(&pdev->dev, "cannot register MDIO bus\n");
	return ret;
	}

	platform_set_drvdata(pdev, bus);

	return 0;
	}

	static const struct of_device_id xgmac_mdio_match[] = {
	{
	.compatible = "fsl,fman-xmdio",
	},
	{
	.compatible = "fsl,fman-memac-mdio",
	},
	{},
	};
	MODULE_DEVICE_TABLE(of, xgmac_mdio_match);

	static const struct acpi_device_id xgmac_acpi_match[] = {
	{ "NXP0006" },
	{ }
	};
	MODULE_DEVICE_TABLE(acpi, xgmac_acpi_match);

	static struct platform_driver xgmac_mdio_driver = {
	.driver = {
	.name = "fsl-fman_xmdio",
	.of_match_table = xgmac_mdio_match,
	.acpi_match_table = xgmac_acpi_match,
	},
	.probe = xgmac_mdio_probe,
	};

	module_platform_driver(xgmac_mdio_driver);

	MODULE_DESCRIPTION("Freescale QorIQ 10G MDIO Controller");
	MODULE_LICENSE("GPL v2");