commit c673ce2ce358f473e81292af6b59d6fdc62f5ade
Author: Andre Przywara <andre.przywara@arm.com>
Date:   Tue Feb 28 22:23:35 2017 +0000

    PHY: faulty 8211E workaround

diff --git a/drivers/net/phy/realtek.c b/drivers/net/phy/realtek.c
index 9cbe645..331183f 100644
--- a/drivers/net/phy/realtek.c
+++ b/drivers/net/phy/realtek.c
@@ -15,6 +15,7 @@
  */
 #include <linux/phy.h>
 #include <linux/module.h>
+#include <linux/of.h>

 #define RTL821x_PHYSR      0x11
 #define RTL821x_PHYSR_DUPLEX   0x2000
@@ -23,6 +24,8 @@
 #define RTL821x_INER_INIT  0x6400
 #define RTL821x_INSR       0x13
 #define RTL8211E_INER_LINK_STATUS 0x400
+#define RTL8211E_EXTENSION_PAGE    0x7
+#define RTL8211E_EXT_PAGE_SEL  0x1e

 #define RTL8211F_INER_LINK_STATUS 0x0010
 #define RTL8211F_INSR      0x1d
@@ -67,6 +70,33 @@ static int rtl8211b_config_intr(struct phy_device *phydev)
    return err;
 }

+static int rtl8211e_config_init(struct phy_device *phydev)
+{
+   struct device_node *of_node = phydev->mdio.dev.of_node;
+
+   if (!of_node)
+       return 0;
+
+   if (!of_property_read_bool(of_node, "disable-rx-delay")) {
+       pr_info("8211E PHY, but no DT property\n");
+       return 0;
+   }
+
+   /* This is a workaround for a batch of faulty PHY chips, found
+    * on a range of Pine64 boards. The RX delay needs to be disabled
+    * completely (the normal rx_delay of 0 programmable by the driver
+    * is not "short enough").
+    */
+   phy_write(phydev, RTL8211F_PAGE_SELECT, RTL8211E_EXTENSION_PAGE);
+   phy_write(phydev, RTL8211E_EXT_PAGE_SEL, 0x00a4);
+   /* Recommended by Realtek engineers, without further explanation. */
+   phy_write(phydev, 0x1c, 0xb591);
+   phy_write(phydev, RTL8211F_PAGE_SELECT, 0x0);
+   pr_info("Applied RTL8211E PHY fix to disable RX delay.\n");
+
+   return 0;
+}
+
 static int rtl8211e_config_intr(struct phy_device *phydev)
 {
    int err;
@@ -156,6 +186,7 @@ static struct phy_driver realtek_drvs[] = {
        .phy_id_mask    = 0x001fffff,
        .features   = PHY_GBIT_FEATURES,
        .flags      = PHY_HAS_INTERRUPT,
+       .config_init    = rtl8211e_config_init,
        .config_aneg    = &genphy_config_aneg,
        .read_status    = &genphy_read_status,
        .ack_interrupt  = &rtl821x_ack_interrupt,