[3.16.y-ckt stable] Patch "smsc911x: power-up phydev before doing a software reset." has been added to staging queue

[Luis Henriques]

This is a note to let you know that I have just added a patch titled

    smsc911x: power-up phydev before doing a software reset.

to the linux-3.16.y-queue branch of the 3.16.y-ckt extended stable tree 
which can be found at:

 http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.16.y-queue

This patch is scheduled to be released in version 3.16.7-ckt2.

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.16.y-ckt tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Luis

------

>From ed98d8e51cfaad4bc66dd5b45f3db83bad8fb476 Mon Sep 17 00:00:00 2001
From: Enric Balletbo i Serra <eballetbo at iseebcn.com>
Date: Thu, 13 Nov 2014 09:14:34 +0100
Subject: smsc911x: power-up phydev before doing a software reset.

commit ccf899a27c08038db91765ff12bb0380dcd85887 upstream.

With commit be9dad1f9f26604fb ("net: phy: suspend phydev when going
to HALTED"), the PHY device will be put in a low-power mode using
BMCR_PDOWN if the the interface is set down. The smsc911x driver does
a software_reset opening the device driver (ndo_open). In such case,
the PHY must be powered-up before access to any register and before
calling the software_reset function. Otherwise, as the PHY is powered
down the software reset fails and the interface can not be enabled
again.

This patch fixes this scenario that is easy to reproduce setting down
the network interface and setting up again.

    $ ifconfig eth0 down
    $ ifconfig eth0 up
    ifconfig: SIOCSIFFLAGS: Input/output error

Signed-off-by: Enric Balletbo i Serra <eballetbo at iseebcn.com>
Signed-off-by: David S. Miller <davem at davemloft.net>
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 drivers/net/ethernet/smsc/smsc911x.c | 46 ++++++++++++++++++++++++++++++++++++
 1 file changed, 46 insertions(+)

diff --git a/drivers/net/ethernet/smsc/smsc911x.c b/drivers/net/ethernet/smsc/smsc911x.c
index 5e13fa5524ae..a4400035681f 100644
--- a/drivers/net/ethernet/smsc/smsc911x.c
+++ b/drivers/net/ethernet/smsc/smsc911x.c
@@ -1342,6 +1342,42 @@ static void smsc911x_rx_multicast_update_workaround(struct smsc911x_data *pdata)
 	spin_unlock(&pdata->mac_lock);
 }

+static int smsc911x_phy_general_power_up(struct smsc911x_data *pdata)
+{
+	int rc = 0;
+
+	if (!pdata->phy_dev)
+		return rc;
+
+	/* If the internal PHY is in General Power-Down mode, all, except the
+	 * management interface, is powered-down and stays in that condition as
+	 * long as Phy register bit 0.11 is HIGH.
+	 *
+	 * In that case, clear the bit 0.11, so the PHY powers up and we can
+	 * access to the phy registers.
+	 */
+	rc = phy_read(pdata->phy_dev, MII_BMCR);
+	if (rc < 0) {
+		SMSC_WARN(pdata, drv, "Failed reading PHY control reg");
+		return rc;
+	}
+
+	/* If the PHY general power-down bit is not set is not necessary to
+	 * disable the general power down-mode.
+	 */
+	if (rc & BMCR_PDOWN) {
+		rc = phy_write(pdata->phy_dev, MII_BMCR, rc & ~BMCR_PDOWN);
+		if (rc < 0) {
+			SMSC_WARN(pdata, drv, "Failed writing PHY control reg");
+			return rc;
+		}
+
+		usleep_range(1000, 1500);
+	}
+
+	return 0;
+}
+
 static int smsc911x_phy_disable_energy_detect(struct smsc911x_data *pdata)
 {
 	int rc = 0;
@@ -1415,6 +1451,16 @@ static int smsc911x_soft_reset(struct smsc911x_data *pdata)
 	int ret;

 	/*
+	 * Make sure to power-up the PHY chip before doing a reset, otherwise
+	 * the reset fails.
+	 */
+	ret = smsc911x_phy_general_power_up(pdata);
+	if (ret) {
+		SMSC_WARN(pdata, drv, "Failed to power-up the PHY chip");
+		return 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
--
2.1.0