drivers/net/ethernet/sfc/falcon/mdio_10g.c - kernel/msm-4.19 - Gitiles

 /****************************************************************************
  * Driver for Solarflare network controllers and boards
  * Copyright 2006-2011 Solarflare Communications Inc.
  *
  * 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, incorporated herein by reference.
  */
 /*
  * Useful functions for working with MDIO clause 45 PHYs
  */
 #include <linux/types.h>
 #include <linux/ethtool.h>
 #include <linux/delay.h>
 #include "net_driver.h"
 #include "mdio_10g.h"
 #include "workarounds.h"

 unsigned ef4_mdio_id_oui(u32 id)
 {
 	unsigned oui = 0;
 	int i;

 	/* The bits of the OUI are designated a..x, with a=0 and b variable.
 	 * In the id register c is the MSB but the OUI is conventionally
 	 * written as bytes h..a, p..i, x..q.  Reorder the bits accordingly. */
 	for (i = 0; i < 22; ++i)
 		if (id & (1 << (i + 10)))
 			oui |= 1 << (i ^ 7);

 	return oui;
 }

 int ef4_mdio_reset_mmd(struct ef4_nic *port, int mmd,
 			    int spins, int spintime)
 {
 	u32 ctrl;

 	/* Catch callers passing values in the wrong units (or just silly) */
 	EF4_BUG_ON_PARANOID(spins * spintime >= 5000);

 	ef4_mdio_write(port, mmd, MDIO_CTRL1, MDIO_CTRL1_RESET);
 	/* Wait for the reset bit to clear. */
 	do {
 		msleep(spintime);
 		ctrl = ef4_mdio_read(port, mmd, MDIO_CTRL1);
 		spins--;

 	} while (spins && (ctrl & MDIO_CTRL1_RESET));

 	return spins ? spins : -ETIMEDOUT;
 }

 static int ef4_mdio_check_mmd(struct ef4_nic *efx, int mmd)
 {
 	int status;

 	if (mmd != MDIO_MMD_AN) {
 		/* Read MMD STATUS2 to check it is responding. */
 		status = ef4_mdio_read(efx, mmd, MDIO_STAT2);
 		if ((status & MDIO_STAT2_DEVPRST) != MDIO_STAT2_DEVPRST_VAL) {
 			netif_err(efx, hw, efx->net_dev,
 				  "PHY MMD %d not responding.\n", mmd);
 			return -EIO;
 		}
 	}

 	return 0;
 }

 /* This ought to be ridiculous overkill. We expect it to fail rarely */
 #define MDIO45_RESET_TIME	1000 /* ms */
 #define MDIO45_RESET_ITERS	100

 int ef4_mdio_wait_reset_mmds(struct ef4_nic *efx, unsigned int mmd_mask)
 {
 	const int spintime = MDIO45_RESET_TIME / MDIO45_RESET_ITERS;
 	int tries = MDIO45_RESET_ITERS;
 	int rc = 0;
 	int in_reset;

 	while (tries) {
 		int mask = mmd_mask;
 		int mmd = 0;
 		int stat;
 		in_reset = 0;
 		while (mask) {
 			if (mask & 1) {
 				stat = ef4_mdio_read(efx, mmd, MDIO_CTRL1);
 				if (stat < 0) {
 					netif_err(efx, hw, efx->net_dev,
 						  "failed to read status of"
 						  " MMD %d\n", mmd);
 					return -EIO;
 				}
 				if (stat & MDIO_CTRL1_RESET)
 					in_reset |= (1 << mmd);
 			}
 			mask = mask >> 1;
 			mmd++;
 		}
 		if (!in_reset)
 			break;
 		tries--;
 		msleep(spintime);
 	}
 	if (in_reset != 0) {
 		netif_err(efx, hw, efx->net_dev,
 			  "not all MMDs came out of reset in time."
 			  " MMDs still in reset: %x\n", in_reset);
 		rc = -ETIMEDOUT;
 	}
 	return rc;
 }

 int ef4_mdio_check_mmds(struct ef4_nic *efx, unsigned int mmd_mask)
 {
 	int mmd = 0, probe_mmd, devs1, devs2;
 	u32 devices;

 	/* Historically we have probed the PHYXS to find out what devices are
 	 * present,but that doesn't work so well if the PHYXS isn't expected
 	 * to exist, if so just find the first item in the list supplied. */
 	probe_mmd = (mmd_mask & MDIO_DEVS_PHYXS) ? MDIO_MMD_PHYXS :
 	    __ffs(mmd_mask);

 	/* Check all the expected MMDs are present */
 	devs1 = ef4_mdio_read(efx, probe_mmd, MDIO_DEVS1);
 	devs2 = ef4_mdio_read(efx, probe_mmd, MDIO_DEVS2);
 	if (devs1 < 0 || devs2 < 0) {
 		netif_err(efx, hw, efx->net_dev,
 			  "failed to read devices present\n");
 		return -EIO;
 	}
 	devices = devs1 | (devs2 << 16);
 	if ((devices & mmd_mask) != mmd_mask) {
 		netif_err(efx, hw, efx->net_dev,
 			  "required MMDs not present: got %x, wanted %x\n",
 			  devices, mmd_mask);
 		return -ENODEV;
 	}
 	netif_vdbg(efx, hw, efx->net_dev, "Devices present: %x\n", devices);

 	/* Check all required MMDs are responding and happy. */
 	while (mmd_mask) {
 		if ((mmd_mask & 1) && ef4_mdio_check_mmd(efx, mmd))
 			return -EIO;
 		mmd_mask = mmd_mask >> 1;
 		mmd++;
 	}

 	return 0;
 }

 bool ef4_mdio_links_ok(struct ef4_nic *efx, unsigned int mmd_mask)
 {
 	/* If the port is in loopback, then we should only consider a subset
 	 * of mmd's */
 	if (LOOPBACK_INTERNAL(efx))
 		return true;
 	else if (LOOPBACK_MASK(efx) & LOOPBACKS_WS)
 		return false;
 	else if (ef4_phy_mode_disabled(efx->phy_mode))
 		return false;
 	else if (efx->loopback_mode == LOOPBACK_PHYXS)
 		mmd_mask &= ~(MDIO_DEVS_PHYXS |
 			      MDIO_DEVS_PCS |
 			      MDIO_DEVS_PMAPMD |
 			      MDIO_DEVS_AN);
 	else if (efx->loopback_mode == LOOPBACK_PCS)
 		mmd_mask &= ~(MDIO_DEVS_PCS |
 			      MDIO_DEVS_PMAPMD |
 			      MDIO_DEVS_AN);
 	else if (efx->loopback_mode == LOOPBACK_PMAPMD)
 		mmd_mask &= ~(MDIO_DEVS_PMAPMD |
 			      MDIO_DEVS_AN);

 	return mdio45_links_ok(&efx->mdio, mmd_mask);
 }

 void ef4_mdio_transmit_disable(struct ef4_nic *efx)
 {
 	ef4_mdio_set_flag(efx, MDIO_MMD_PMAPMD,
 			  MDIO_PMA_TXDIS, MDIO_PMD_TXDIS_GLOBAL,
 			  efx->phy_mode & PHY_MODE_TX_DISABLED);
 }

 void ef4_mdio_phy_reconfigure(struct ef4_nic *efx)
 {
 	ef4_mdio_set_flag(efx, MDIO_MMD_PMAPMD,
 			  MDIO_CTRL1, MDIO_PMA_CTRL1_LOOPBACK,
 			  efx->loopback_mode == LOOPBACK_PMAPMD);
 	ef4_mdio_set_flag(efx, MDIO_MMD_PCS,
 			  MDIO_CTRL1, MDIO_PCS_CTRL1_LOOPBACK,
 			  efx->loopback_mode == LOOPBACK_PCS);
 	ef4_mdio_set_flag(efx, MDIO_MMD_PHYXS,
 			  MDIO_CTRL1, MDIO_PHYXS_CTRL1_LOOPBACK,
 			  efx->loopback_mode == LOOPBACK_PHYXS_WS);
 }

 static void ef4_mdio_set_mmd_lpower(struct ef4_nic *efx,
 				    int lpower, int mmd)
 {
 	int stat = ef4_mdio_read(efx, mmd, MDIO_STAT1);

 	netif_vdbg(efx, drv, efx->net_dev, "Setting low power mode for MMD %d to %d\n",
 		  mmd, lpower);

 	if (stat & MDIO_STAT1_LPOWERABLE) {
 		ef4_mdio_set_flag(efx, mmd, MDIO_CTRL1,
 				  MDIO_CTRL1_LPOWER, lpower);
 	}
 }

 void ef4_mdio_set_mmds_lpower(struct ef4_nic *efx,
 			      int low_power, unsigned int mmd_mask)
 {
 	int mmd = 0;
 	mmd_mask &= ~MDIO_DEVS_AN;
 	while (mmd_mask) {
 		if (mmd_mask & 1)
 			ef4_mdio_set_mmd_lpower(efx, low_power, mmd);
 		mmd_mask = (mmd_mask >> 1);
 		mmd++;
 	}
 }

 /**
  * ef4_mdio_set_settings - Set (some of) the PHY settings over MDIO.
  * @efx:		Efx NIC
  * @ecmd:		New settings
  */
 int ef4_mdio_set_settings(struct ef4_nic *efx, struct ethtool_cmd *ecmd)
 {
 	struct ethtool_cmd prev = { .cmd = ETHTOOL_GSET };

 	efx->phy_op->get_settings(efx, &prev);

 	if (ecmd->advertising == prev.advertising &&
 	    ethtool_cmd_speed(ecmd) == ethtool_cmd_speed(&prev) &&
 	    ecmd->duplex == prev.duplex &&
 	    ecmd->port == prev.port &&
 	    ecmd->autoneg == prev.autoneg)
 		return 0;

 	/* We can only change these settings for -T PHYs */
 	if (prev.port != PORT_TP || ecmd->port != PORT_TP)
 		return -EINVAL;

 	/* Check that PHY supports these settings */
 	if (!ecmd->autoneg ||
 	    (ecmd->advertising | SUPPORTED_Autoneg) & ~prev.supported)
 		return -EINVAL;

 	ef4_link_set_advertising(efx, ecmd->advertising | ADVERTISED_Autoneg);
 	ef4_mdio_an_reconfigure(efx);
 	return 0;
 }

 /**
  * ef4_mdio_an_reconfigure - Push advertising flags and restart autonegotiation
  * @efx:		Efx NIC
  */
 void ef4_mdio_an_reconfigure(struct ef4_nic *efx)
 {
 	int reg;

 	WARN_ON(!(efx->mdio.mmds & MDIO_DEVS_AN));

 	/* Set up the base page */
 	reg = ADVERTISE_CSMA | ADVERTISE_RESV;
 	if (efx->link_advertising & ADVERTISED_Pause)
 		reg |= ADVERTISE_PAUSE_CAP;
 	if (efx->link_advertising & ADVERTISED_Asym_Pause)
 		reg |= ADVERTISE_PAUSE_ASYM;
 	ef4_mdio_write(efx, MDIO_MMD_AN, MDIO_AN_ADVERTISE, reg);

 	/* Set up the (extended) next page */
 	efx->phy_op->set_npage_adv(efx, efx->link_advertising);

 	/* Enable and restart AN */
 	reg = ef4_mdio_read(efx, MDIO_MMD_AN, MDIO_CTRL1);
 	reg |= MDIO_AN_CTRL1_ENABLE | MDIO_AN_CTRL1_RESTART | MDIO_AN_CTRL1_XNP;
 	ef4_mdio_write(efx, MDIO_MMD_AN, MDIO_CTRL1, reg);
 }

 u8 ef4_mdio_get_pause(struct ef4_nic *efx)
 {
 	BUILD_BUG_ON(EF4_FC_AUTO & (EF4_FC_RX | EF4_FC_TX));

 	if (!(efx->wanted_fc & EF4_FC_AUTO))
 		return efx->wanted_fc;

 	WARN_ON(!(efx->mdio.mmds & MDIO_DEVS_AN));

 	return mii_resolve_flowctrl_fdx(
 		mii_advertise_flowctrl(efx->wanted_fc),
 		ef4_mdio_read(efx, MDIO_MMD_AN, MDIO_AN_LPA));
 }

 int ef4_mdio_test_alive(struct ef4_nic *efx)
 {
 	int rc;
 	int devad = __ffs(efx->mdio.mmds);
 	u16 physid1, physid2;

 	mutex_lock(&efx->mac_lock);

 	physid1 = ef4_mdio_read(efx, devad, MDIO_DEVID1);
 	physid2 = ef4_mdio_read(efx, devad, MDIO_DEVID2);

 	if ((physid1 == 0x0000) || (physid1 == 0xffff) ||
 	    (physid2 == 0x0000) || (physid2 == 0xffff)) {
 		netif_err(efx, hw, efx->net_dev,
 			  "no MDIO PHY present with ID %d\n", efx->mdio.prtad);
 		rc = -EINVAL;
 	} else {
 		rc = ef4_mdio_check_mmds(efx, efx->mdio.mmds);
 	}

 	mutex_unlock(&efx->mac_lock);
 	return rc;
 }
	/****************************************************************************
	* Driver for Solarflare network controllers and boards
	* Copyright 2006-2011 Solarflare Communications Inc.
	*
	* 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, incorporated herein by reference.
	*/
	/*
	* Useful functions for working with MDIO clause 45 PHYs
	*/
	#include <linux/types.h>
	#include <linux/ethtool.h>
	#include <linux/delay.h>
	#include "net_driver.h"
	#include "mdio_10g.h"
	#include "workarounds.h"

	unsigned ef4_mdio_id_oui(u32 id)
	{
	unsigned oui = 0;
	int i;

	/* The bits of the OUI are designated a..x, with a=0 and b variable.
	* In the id register c is the MSB but the OUI is conventionally
	* written as bytes h..a, p..i, x..q. Reorder the bits accordingly. */
	for (i = 0; i < 22; ++i)
	if (id & (1 << (i + 10)))
	oui \|= 1 << (i ^ 7);

	return oui;
	}

	int ef4_mdio_reset_mmd(struct ef4_nic *port, int mmd,
	int spins, int spintime)
	{
	u32 ctrl;

	/* Catch callers passing values in the wrong units (or just silly) */
	EF4_BUG_ON_PARANOID(spins * spintime >= 5000);

	ef4_mdio_write(port, mmd, MDIO_CTRL1, MDIO_CTRL1_RESET);
	/* Wait for the reset bit to clear. */
	do {
	msleep(spintime);
	ctrl = ef4_mdio_read(port, mmd, MDIO_CTRL1);
	spins--;

	} while (spins && (ctrl & MDIO_CTRL1_RESET));

	return spins ? spins : -ETIMEDOUT;
	}

	static int ef4_mdio_check_mmd(struct ef4_nic *efx, int mmd)
	{
	int status;

	if (mmd != MDIO_MMD_AN) {
	/* Read MMD STATUS2 to check it is responding. */
	status = ef4_mdio_read(efx, mmd, MDIO_STAT2);
	if ((status & MDIO_STAT2_DEVPRST) != MDIO_STAT2_DEVPRST_VAL) {
	netif_err(efx, hw, efx->net_dev,
	"PHY MMD %d not responding.\n", mmd);
	return -EIO;
	}
	}

	return 0;
	}

	/* This ought to be ridiculous overkill. We expect it to fail rarely */
	#define MDIO45_RESET_TIME 1000 /* ms */
	#define MDIO45_RESET_ITERS 100

	int ef4_mdio_wait_reset_mmds(struct ef4_nic *efx, unsigned int mmd_mask)
	{
	const int spintime = MDIO45_RESET_TIME / MDIO45_RESET_ITERS;
	int tries = MDIO45_RESET_ITERS;
	int rc = 0;
	int in_reset;

	while (tries) {
	int mask = mmd_mask;
	int mmd = 0;
	int stat;
	in_reset = 0;
	while (mask) {
	if (mask & 1) {
	stat = ef4_mdio_read(efx, mmd, MDIO_CTRL1);
	if (stat < 0) {
	netif_err(efx, hw, efx->net_dev,
	"failed to read status of"
	" MMD %d\n", mmd);
	return -EIO;
	}
	if (stat & MDIO_CTRL1_RESET)
	in_reset \|= (1 << mmd);
	}
	mask = mask >> 1;
	mmd++;
	}
	if (!in_reset)
	break;
	tries--;
	msleep(spintime);
	}
	if (in_reset != 0) {
	netif_err(efx, hw, efx->net_dev,
	"not all MMDs came out of reset in time."
	" MMDs still in reset: %x\n", in_reset);
	rc = -ETIMEDOUT;
	}
	return rc;
	}

	int ef4_mdio_check_mmds(struct ef4_nic *efx, unsigned int mmd_mask)
	{
	int mmd = 0, probe_mmd, devs1, devs2;
	u32 devices;

	/* Historically we have probed the PHYXS to find out what devices are
	* present,but that doesn't work so well if the PHYXS isn't expected
	* to exist, if so just find the first item in the list supplied. */
	probe_mmd = (mmd_mask & MDIO_DEVS_PHYXS) ? MDIO_MMD_PHYXS :
	__ffs(mmd_mask);

	/* Check all the expected MMDs are present */
	devs1 = ef4_mdio_read(efx, probe_mmd, MDIO_DEVS1);
	devs2 = ef4_mdio_read(efx, probe_mmd, MDIO_DEVS2);
	if (devs1 < 0 \|\| devs2 < 0) {
	netif_err(efx, hw, efx->net_dev,
	"failed to read devices present\n");
	return -EIO;
	}
	devices = devs1 \| (devs2 << 16);
	if ((devices & mmd_mask) != mmd_mask) {
	netif_err(efx, hw, efx->net_dev,
	"required MMDs not present: got %x, wanted %x\n",
	devices, mmd_mask);
	return -ENODEV;
	}
	netif_vdbg(efx, hw, efx->net_dev, "Devices present: %x\n", devices);

	/* Check all required MMDs are responding and happy. */
	while (mmd_mask) {
	if ((mmd_mask & 1) && ef4_mdio_check_mmd(efx, mmd))
	return -EIO;
	mmd_mask = mmd_mask >> 1;
	mmd++;
	}

	return 0;
	}

	bool ef4_mdio_links_ok(struct ef4_nic *efx, unsigned int mmd_mask)
	{
	/* If the port is in loopback, then we should only consider a subset
	* of mmd's */
	if (LOOPBACK_INTERNAL(efx))
	return true;
	else if (LOOPBACK_MASK(efx) & LOOPBACKS_WS)
	return false;
	else if (ef4_phy_mode_disabled(efx->phy_mode))
	return false;
	else if (efx->loopback_mode == LOOPBACK_PHYXS)
	mmd_mask &= ~(MDIO_DEVS_PHYXS \|
	MDIO_DEVS_PCS \|
	MDIO_DEVS_PMAPMD \|
	MDIO_DEVS_AN);
	else if (efx->loopback_mode == LOOPBACK_PCS)
	mmd_mask &= ~(MDIO_DEVS_PCS \|
	MDIO_DEVS_PMAPMD \|
	MDIO_DEVS_AN);
	else if (efx->loopback_mode == LOOPBACK_PMAPMD)
	mmd_mask &= ~(MDIO_DEVS_PMAPMD \|
	MDIO_DEVS_AN);

	return mdio45_links_ok(&efx->mdio, mmd_mask);
	}

	void ef4_mdio_transmit_disable(struct ef4_nic *efx)
	{
	ef4_mdio_set_flag(efx, MDIO_MMD_PMAPMD,
	MDIO_PMA_TXDIS, MDIO_PMD_TXDIS_GLOBAL,
	efx->phy_mode & PHY_MODE_TX_DISABLED);
	}

	void ef4_mdio_phy_reconfigure(struct ef4_nic *efx)
	{
	ef4_mdio_set_flag(efx, MDIO_MMD_PMAPMD,
	MDIO_CTRL1, MDIO_PMA_CTRL1_LOOPBACK,
	efx->loopback_mode == LOOPBACK_PMAPMD);
	ef4_mdio_set_flag(efx, MDIO_MMD_PCS,
	MDIO_CTRL1, MDIO_PCS_CTRL1_LOOPBACK,
	efx->loopback_mode == LOOPBACK_PCS);
	ef4_mdio_set_flag(efx, MDIO_MMD_PHYXS,
	MDIO_CTRL1, MDIO_PHYXS_CTRL1_LOOPBACK,
	efx->loopback_mode == LOOPBACK_PHYXS_WS);
	}

	static void ef4_mdio_set_mmd_lpower(struct ef4_nic *efx,
	int lpower, int mmd)
	{
	int stat = ef4_mdio_read(efx, mmd, MDIO_STAT1);

	netif_vdbg(efx, drv, efx->net_dev, "Setting low power mode for MMD %d to %d\n",
	mmd, lpower);

	if (stat & MDIO_STAT1_LPOWERABLE) {
	ef4_mdio_set_flag(efx, mmd, MDIO_CTRL1,
	MDIO_CTRL1_LPOWER, lpower);
	}
	}

	void ef4_mdio_set_mmds_lpower(struct ef4_nic *efx,
	int low_power, unsigned int mmd_mask)
	{
	int mmd = 0;
	mmd_mask &= ~MDIO_DEVS_AN;
	while (mmd_mask) {
	if (mmd_mask & 1)
	ef4_mdio_set_mmd_lpower(efx, low_power, mmd);
	mmd_mask = (mmd_mask >> 1);
	mmd++;
	}
	}

	/**
	* ef4_mdio_set_settings - Set (some of) the PHY settings over MDIO.
	* @efx: Efx NIC
	* @ecmd: New settings
	*/
	int ef4_mdio_set_settings(struct ef4_nic efx, struct ethtool_cmd ecmd)
	{
	struct ethtool_cmd prev = { .cmd = ETHTOOL_GSET };

	efx->phy_op->get_settings(efx, &prev);

	if (ecmd->advertising == prev.advertising &&
	ethtool_cmd_speed(ecmd) == ethtool_cmd_speed(&prev) &&
	ecmd->duplex == prev.duplex &&
	ecmd->port == prev.port &&
	ecmd->autoneg == prev.autoneg)
	return 0;

	/* We can only change these settings for -T PHYs */
	if (prev.port != PORT_TP \|\| ecmd->port != PORT_TP)
	return -EINVAL;

	/* Check that PHY supports these settings */
	if (!ecmd->autoneg \|\|
	(ecmd->advertising \| SUPPORTED_Autoneg) & ~prev.supported)
	return -EINVAL;

	ef4_link_set_advertising(efx, ecmd->advertising \| ADVERTISED_Autoneg);
	ef4_mdio_an_reconfigure(efx);
	return 0;
	}

	/**
	* ef4_mdio_an_reconfigure - Push advertising flags and restart autonegotiation
	* @efx: Efx NIC
	*/
	void ef4_mdio_an_reconfigure(struct ef4_nic *efx)
	{
	int reg;

	WARN_ON(!(efx->mdio.mmds & MDIO_DEVS_AN));

	/* Set up the base page */
	reg = ADVERTISE_CSMA \| ADVERTISE_RESV;
	if (efx->link_advertising & ADVERTISED_Pause)
	reg \|= ADVERTISE_PAUSE_CAP;
	if (efx->link_advertising & ADVERTISED_Asym_Pause)
	reg \|= ADVERTISE_PAUSE_ASYM;
	ef4_mdio_write(efx, MDIO_MMD_AN, MDIO_AN_ADVERTISE, reg);

	/* Set up the (extended) next page */
	efx->phy_op->set_npage_adv(efx, efx->link_advertising);

	/* Enable and restart AN */
	reg = ef4_mdio_read(efx, MDIO_MMD_AN, MDIO_CTRL1);
	reg \|= MDIO_AN_CTRL1_ENABLE \| MDIO_AN_CTRL1_RESTART \| MDIO_AN_CTRL1_XNP;
	ef4_mdio_write(efx, MDIO_MMD_AN, MDIO_CTRL1, reg);
	}

	u8 ef4_mdio_get_pause(struct ef4_nic *efx)
	{
	BUILD_BUG_ON(EF4_FC_AUTO & (EF4_FC_RX \| EF4_FC_TX));

	if (!(efx->wanted_fc & EF4_FC_AUTO))
	return efx->wanted_fc;

	WARN_ON(!(efx->mdio.mmds & MDIO_DEVS_AN));

	return mii_resolve_flowctrl_fdx(
	mii_advertise_flowctrl(efx->wanted_fc),
	ef4_mdio_read(efx, MDIO_MMD_AN, MDIO_AN_LPA));
	}

	int ef4_mdio_test_alive(struct ef4_nic *efx)
	{
	int rc;
	int devad = __ffs(efx->mdio.mmds);
	u16 physid1, physid2;

	mutex_lock(&efx->mac_lock);

	physid1 = ef4_mdio_read(efx, devad, MDIO_DEVID1);
	physid2 = ef4_mdio_read(efx, devad, MDIO_DEVID2);

	if ((physid1 == 0x0000) \|\| (physid1 == 0xffff) \|\|
	(physid2 == 0x0000) \|\| (physid2 == 0xffff)) {
	netif_err(efx, hw, efx->net_dev,
	"no MDIO PHY present with ID %d\n", efx->mdio.prtad);
	rc = -EINVAL;
	} else {
	rc = ef4_mdio_check_mmds(efx, efx->mdio.mmds);
	}

	mutex_unlock(&efx->mac_lock);
	return rc;
	}