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Commit 6386994e authored by Javier Martinez Canillas's avatar Javier Martinez Canillas Committed by David S. Miller
Browse files

net/smsc911x: Check if PHY is in operational mode before software reset 



SMSC LAN generation 4 chips integrate an IEEE 802.3 ethernet physical layer.
The PHY driver for this integrated chip enable an energy detect power-down mode.
When the PHY is in a power-down mode, it prevents the MAC portion chip to be
software reseted.

That means that if we compile the kernel with the configuration option SMSC_PHY
enabled and try to bring the network interface up without an cable plug-ed the
PHY will be in a low power mode and the software reset will fail returning -EIO
to user-space:

root@igep00x0:~# ifconfig eth0 up
ifconfig: SIOCSIFFLAGS: Input/output error

This patch disable the energy detect power-down mode before trying to software
reset the LAN chip and re-enables after it was reseted successfully.

Signed-off-by: default avatarJavier Martinez Canillas <javier@dowhile0.org>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 43c6759e

drivers/net/ethernet/smsc/smsc911x.c

+92 −0
Original line number Diff line number Diff line
@@ -1319,10 +1319,92 @@ static void smsc911x_rx_multicast_update_workaround(struct smsc911x_data *pdata) 
	spin_unlock(&pdata->mac_lock);

}



static int smsc911x_phy_disable_energy_detect(struct smsc911x_data *pdata)

{

	int rc = 0;



	if (!pdata->phy_dev)

		return rc;



	rc = phy_read(pdata->phy_dev, MII_LAN83C185_CTRL_STATUS);



	if (rc < 0) {

		SMSC_WARN(pdata, drv, "Failed reading PHY control reg");

		return rc;

	}



	/*

	 * If energy is detected the PHY is already awake so is not necessary

	 * to disable the energy detect power-down mode.

	 */

	if ((rc & MII_LAN83C185_EDPWRDOWN) &&

	    !(rc & MII_LAN83C185_ENERGYON)) {

		/* Disable energy detect mode for this SMSC Transceivers */

		rc = phy_write(pdata->phy_dev, MII_LAN83C185_CTRL_STATUS,

			       rc & (~MII_LAN83C185_EDPWRDOWN));



		if (rc < 0) {

			SMSC_WARN(pdata, drv, "Failed writing PHY control reg");

			return rc;

		}



		mdelay(1);

	}



	return 0;

}



static int smsc911x_phy_enable_energy_detect(struct smsc911x_data *pdata)

{

	int rc = 0;



	if (!pdata->phy_dev)

		return rc;



	rc = phy_read(pdata->phy_dev, MII_LAN83C185_CTRL_STATUS);



	if (rc < 0) {

		SMSC_WARN(pdata, drv, "Failed reading PHY control reg");

		return rc;

	}



	/* Only enable if energy detect mode is already disabled */

	if (!(rc & MII_LAN83C185_EDPWRDOWN)) {

		mdelay(100);

		/* Enable energy detect mode for this SMSC Transceivers */

		rc = phy_write(pdata->phy_dev, MII_LAN83C185_CTRL_STATUS,

			       rc | MII_LAN83C185_EDPWRDOWN);



		if (rc < 0) {

			SMSC_WARN(pdata, drv, "Failed writing PHY control reg");

			return rc;

		}



		mdelay(1);

	}

	return 0;

}



static int smsc911x_soft_reset(struct smsc911x_data *pdata)

{

	unsigned int timeout;

	unsigned int temp;

	int ret;



	/*

	 * LAN9210/LAN9211/LAN9220/LAN9221 chips have an internal PHY that

	 * are initialized in a Energy Detect Power-Down mode that prevents

	 * the MAC chip to be software reseted. So we have to wakeup the PHY

	 * before.

	 */

	if (pdata->generation == 4) {

		ret = smsc911x_phy_disable_energy_detect(pdata);



		if (ret) {

			SMSC_WARN(pdata, drv, "Failed to wakeup the PHY chip");

			return ret;

		}

	}



	/* Reset the LAN911x */

	smsc911x_reg_write(pdata, HW_CFG, HW_CFG_SRST_);
@@ -1336,6 +1418,16 @@ static int smsc911x_soft_reset(struct smsc911x_data *pdata) 
		SMSC_WARN(pdata, drv, "Failed to complete reset");

		return -EIO;

	}



	if (pdata->generation == 4) {

		ret = smsc911x_phy_enable_energy_detect(pdata);



		if (ret) {

			SMSC_WARN(pdata, drv, "Failed to wakeup the PHY chip");

			return ret;

		}

	}



	return 0;

}