linux/drivers/net/ethernet/freescale/enetc/enetc_mdio.c

// SPDX-License-Identifier: (GPL-2.0+ OR BSD-3-Clause)
/* Copyright 2019 NXP */

#include <linux/mdio.h>
#include <linux/of_mdio.h>
#include <linux/iopoll.h>
#include <linux/of.h>

#include "enetc_mdio.h"

#define	ENETC_MDIO_REG_OFFSET	0x1c00
#define	ENETC_MDIO_CFG	0x0	/* MDIO configuration and status */
#define	ENETC_MDIO_CTL	0x4	/* MDIO control */
#define	ENETC_MDIO_DATA	0x8	/* MDIO data */
#define	ENETC_MDIO_ADDR	0xc	/* MDIO address */

#define enetc_mdio_rd(hw, off) \
	enetc_port_rd(hw, ENETC_##off + ENETC_MDIO_REG_OFFSET)
#define enetc_mdio_wr(hw, off, val) \
	enetc_port_wr(hw, ENETC_##off + ENETC_MDIO_REG_OFFSET, val)
#define enetc_mdio_rd_reg(off)	enetc_mdio_rd(hw, off)

#define ENETC_MDC_DIV		258

#define MDIO_CFG_CLKDIV(x)	((((x) >> 1) & 0xff) << 8)
#define MDIO_CFG_BSY		BIT(0)
#define MDIO_CFG_RD_ER		BIT(1)
#define MDIO_CFG_ENC45		BIT(6)
 /* external MDIO only - driven on neg MDC edge */
#define MDIO_CFG_NEG		BIT(23)

#define MDIO_CTL_DEV_ADDR(x)	((x) & 0x1f)
#define MDIO_CTL_PORT_ADDR(x)	(((x) & 0x1f) << 5)
#define MDIO_CTL_READ		BIT(15)
#define MDIO_DATA(x)		((x) & 0xffff)

#define TIMEOUT	1000
static int enetc_mdio_wait_complete(struct enetc_hw *hw)
{
	u32 val;

	return readx_poll_timeout(enetc_mdio_rd_reg, MDIO_CFG, val,
				  !(val & MDIO_CFG_BSY), 10, 10 * TIMEOUT);
}

int enetc_mdio_write(struct mii_bus *bus, int phy_id, int regnum, u16 value)
{
	struct enetc_mdio_priv *mdio_priv = bus->priv;
	struct enetc_hw *hw = mdio_priv->hw;
	u32 mdio_ctl, mdio_cfg;
	u16 dev_addr;
	int ret;

	mdio_cfg = MDIO_CFG_CLKDIV(ENETC_MDC_DIV) | MDIO_CFG_NEG;
	if (regnum & MII_ADDR_C45) {
		dev_addr = (regnum >> 16) & 0x1f;
		mdio_cfg |= MDIO_CFG_ENC45;
	} else {
		/* clause 22 (ie 1G) */
		dev_addr = regnum & 0x1f;
		mdio_cfg &= ~MDIO_CFG_ENC45;
	}

	enetc_mdio_wr(hw, MDIO_CFG, mdio_cfg);

	ret = enetc_mdio_wait_complete(hw);
	if (ret)
		return ret;

	/* set port and dev addr */
	mdio_ctl = MDIO_CTL_PORT_ADDR(phy_id) | MDIO_CTL_DEV_ADDR(dev_addr);
	enetc_mdio_wr(hw, MDIO_CTL, mdio_ctl);

	/* set the register address */
	if (regnum & MII_ADDR_C45) {
		enetc_mdio_wr(hw, MDIO_ADDR, regnum & 0xffff);

		ret = enetc_mdio_wait_complete(hw);
		if (ret)
			return ret;
	}

	/* write the value */
	enetc_mdio_wr(hw, MDIO_DATA, MDIO_DATA(value));

	ret = enetc_mdio_wait_complete(hw);
	if (ret)
		return ret;

	return 0;
}

int enetc_mdio_read(struct mii_bus *bus, int phy_id, int regnum)
{
	struct enetc_mdio_priv *mdio_priv = bus->priv;
	struct enetc_hw *hw = mdio_priv->hw;
	u32 mdio_ctl, mdio_cfg;
	u16 dev_addr, value;
	int ret;

	mdio_cfg = MDIO_CFG_CLKDIV(ENETC_MDC_DIV) | MDIO_CFG_NEG;
	if (regnum & MII_ADDR_C45) {
		dev_addr = (regnum >> 16) & 0x1f;
		mdio_cfg |= MDIO_CFG_ENC45;
	} else {
		dev_addr = regnum & 0x1f;
		mdio_cfg &= ~MDIO_CFG_ENC45;
	}

	enetc_mdio_wr(hw, MDIO_CFG, mdio_cfg);

	ret = enetc_mdio_wait_complete(hw);
	if (ret)
		return ret;

	/* set port and device addr */
	mdio_ctl = MDIO_CTL_PORT_ADDR(phy_id) | MDIO_CTL_DEV_ADDR(dev_addr);
	enetc_mdio_wr(hw, MDIO_CTL, mdio_ctl);

	/* set the register address */
	if (regnum & MII_ADDR_C45) {
		enetc_mdio_wr(hw, MDIO_ADDR, regnum & 0xffff);

		ret = enetc_mdio_wait_complete(hw);
		if (ret)
			return ret;
	}

	/* initiate the read */
	enetc_mdio_wr(hw, MDIO_CTL, mdio_ctl | MDIO_CTL_READ);

	ret = enetc_mdio_wait_complete(hw);
	if (ret)
		return ret;

	/* return all Fs if nothing was there */
	if (enetc_mdio_rd(hw, MDIO_CFG) & MDIO_CFG_RD_ER) {
		dev_dbg(&bus->dev,
			"Error while reading PHY%d reg at %d.%hhu\n",
			phy_id, dev_addr, regnum);
		return 0xffff;
	}

	value = enetc_mdio_rd(hw, MDIO_DATA) & 0xffff;

	return value;
}

int enetc_mdio_probe(struct enetc_pf *pf)
{
	struct device *dev = &pf->si->pdev->dev;
	struct enetc_mdio_priv *mdio_priv;
	struct device_node *np;
	struct mii_bus *bus;
	int err;

	bus = devm_mdiobus_alloc_size(dev, sizeof(*mdio_priv));
	if (!bus)
		return -ENOMEM;

	bus->name = "Freescale ENETC MDIO Bus";
	bus->read = enetc_mdio_read;
	bus->write = enetc_mdio_write;
	bus->parent = dev;
	mdio_priv = bus->priv;
	mdio_priv->hw = &pf->si->hw;
	snprintf(bus->id, MII_BUS_ID_SIZE, "%s", dev_name(dev));

	np = of_get_child_by_name(dev->of_node, "mdio");
	if (!np) {
		dev_err(dev, "MDIO node missing\n");
		return -EINVAL;
	}

	err = of_mdiobus_register(bus, np);
	if (err) {
		of_node_put(np);
		dev_err(dev, "cannot register MDIO bus\n");
		return err;
	}

	of_node_put(np);
	pf->mdio = bus;

	return 0;
}

void enetc_mdio_remove(struct enetc_pf *pf)
{
	if (pf->mdio)
		mdiobus_unregister(pf->mdio);
}