[PATCH 4.17 182/324] smsc75xx: Add workaround for gigabit link up hardware errata.

[Greg Kroah-Hartman]

4.17-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Yuiko Oshino <yuiko.osh...@microchip.com>

[ Upstream commit d461e3da905332189aad546b2ad9adbe6071c7cc ]

In certain conditions, the device may not be able to link in gigabit mode. This 
software workaround ensures that the device will not enter the failure state.

Fixes: d0cad871703b898a442e4049c532ec39168e5b57 ("SMSC75XX USB 2.0 Gigabit 
Ethernet Devices")
Signed-off-by: Yuiko Oshino <yuiko.osh...@microchip.com>
Signed-off-by: David S. Miller <da...@davemloft.net>
Signed-off-by: Sasha Levin <alexander.le...@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>
---
 drivers/net/usb/smsc75xx.c |   62 +++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 62 insertions(+)

--- a/drivers/net/usb/smsc75xx.c
+++ b/drivers/net/usb/smsc75xx.c
@@ -82,6 +82,9 @@ static bool turbo_mode = true;
 module_param(turbo_mode, bool, 0644);
 MODULE_PARM_DESC(turbo_mode, "Enable multiple frames per Rx transaction");
 
+static int smsc75xx_link_ok_nopm(struct usbnet *dev);
+static int smsc75xx_phy_gig_workaround(struct usbnet *dev);
+
 static int __must_check __smsc75xx_read_reg(struct usbnet *dev, u32 index,
                                            u32 *data, int in_pm)
 {
@@ -852,6 +855,9 @@ static int smsc75xx_phy_initialize(struc
                return -EIO;
        }
 
+       /* phy workaround for gig link */
+       smsc75xx_phy_gig_workaround(dev);
+
        smsc75xx_mdio_write(dev->net, dev->mii.phy_id, MII_ADVERTISE,
                ADVERTISE_ALL | ADVERTISE_CSMA | ADVERTISE_PAUSE_CAP |
                ADVERTISE_PAUSE_ASYM);
@@ -987,6 +993,62 @@ static int smsc75xx_wait_ready(struct us
        return -EIO;
 }
 
+static int smsc75xx_phy_gig_workaround(struct usbnet *dev)
+{
+       struct mii_if_info *mii = &dev->mii;
+       int ret = 0, timeout = 0;
+       u32 buf, link_up = 0;
+
+       /* Set the phy in Gig loopback */
+       smsc75xx_mdio_write(dev->net, mii->phy_id, MII_BMCR, 0x4040);
+
+       /* Wait for the link up */
+       do {
+               link_up = smsc75xx_link_ok_nopm(dev);
+               usleep_range(10000, 20000);
+               timeout++;
+       } while ((!link_up) && (timeout < 1000));
+
+       if (timeout >= 1000) {
+               netdev_warn(dev->net, "Timeout waiting for PHY link up\n");
+               return -EIO;
+       }
+
+       /* phy reset */
+       ret = smsc75xx_read_reg(dev, PMT_CTL, &buf);
+       if (ret < 0) {
+               netdev_warn(dev->net, "Failed to read PMT_CTL: %d\n", ret);
+               return ret;
+       }
+
+       buf |= PMT_CTL_PHY_RST;
+
+       ret = smsc75xx_write_reg(dev, PMT_CTL, buf);
+       if (ret < 0) {
+               netdev_warn(dev->net, "Failed to write PMT_CTL: %d\n", ret);
+               return ret;
+       }
+
+       timeout = 0;
+       do {
+               usleep_range(10000, 20000);
+               ret = smsc75xx_read_reg(dev, PMT_CTL, &buf);
+               if (ret < 0) {
+                       netdev_warn(dev->net, "Failed to read PMT_CTL: %d\n",
+                                   ret);
+                       return ret;
+               }
+               timeout++;
+       } while ((buf & PMT_CTL_PHY_RST) && (timeout < 100));
+
+       if (timeout >= 100) {
+               netdev_warn(dev->net, "timeout waiting for PHY Reset\n");
+               return -EIO;
+       }
+
+       return 0;
+}
+
 static int smsc75xx_reset(struct usbnet *dev)
 {
        struct smsc75xx_priv *pdata = (struct smsc75xx_priv *)(dev->data[0]);