net: phy: consolidate PHY reset in phy_init_hw()

There are quite a lot of drivers touching a PHY device MII_BMCR
register to reset the PHY without taking care of:

1) ensuring that BMCR_RESET is cleared after a given timeout
2) the PHY state machine resuming to the proper state and re-applying
potentially changed settings such as auto-negotiation

Introduce phy_poll_reset() which will take care of polling the MII_BMCR
for the BMCR_RESET bit to be cleared after a given timeout or return a
timeout error code.

In order to make sure the PHY is in a correct state, phy_init_hw() first
issues a software reset through MII_BMCR and then applies any fixups.

Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 55 insertions, 1 deletions

diff --git a/drivers/net/phy/phy_device.c b/drivers/net/phy/phy_device.c
index 6db36595eac9..5a619f0dcf73 100644
--- a/drivers/net/phy/phy_device.c
+++ b/drivers/net/phy/phy_device.c
@@ -364,7 +364,11 @@ int phy_device_register(struct phy_device *phydev)
         phydev->bus->phy_map[phydev->addr] = phydev;
 
         /* Run all of the fixups for this PHY */
-        phy_scan_fixups(phydev);
+        err = phy_init_hw(phydev);
+        if (err) {
+                pr_err("PHY %d failed to initialize\n", phydev->addr);
+                goto out;
+        }
 
         err = device_add(&phydev->dev);
         if (err) {
@@ -497,6 +501,47 @@ void phy_disconnect(struct phy_device *phydev)
 }
 EXPORT_SYMBOL(phy_disconnect);
 
+/**
+ * phy_poll_reset - Safely wait until a PHY reset has properly completed
+ * @phydev: The PHY device to poll
+ *
+ * Description: According to IEEE 802.3, Section 2, Subsection 22.2.4.1.1, as
+ *   published in 2008, a PHY reset may take up to 0.5 seconds.  The MII BMCR
+ *   register must be polled until the BMCR_RESET bit clears.
+ *
+ *   Furthermore, any attempts to write to PHY registers may have no effect
+ *   or even generate MDIO bus errors until this is complete.
+ *
+ *   Some PHYs (such as the Marvell 88E1111) don't entirely conform to the
+ *   standard and do not fully reset after the BMCR_RESET bit is set, and may
+ *   even *REQUIRE* a soft-reset to properly restart autonegotiation.  In an
+ *   effort to support such broken PHYs, this function is separate from the
+ *   standard phy_init_hw() which will zero all the other bits in the BMCR
+ *   and reapply all driver-specific and board-specific fixups.
+ */
+static int phy_poll_reset(struct phy_device *phydev)
+{
+        /* Poll until the reset bit clears (50ms per retry == 0.6 sec) */
+        unsigned int retries = 12;
+        int ret;
+
+        do {
+                msleep(50);
+                ret = phy_read(phydev, MII_BMCR);
+                if (ret < 0)
+                        return ret;
+        } while (ret & BMCR_RESET && --retries);
+        if (ret & BMCR_RESET)
+                return -ETIMEDOUT;
+
+        /*
+         * Some chips (smsc911x) may still need up to another 1ms after the
+         * BMCR_RESET bit is cleared before they are usable.
+         */
+        msleep(1);
+        return 0;
+}
+
 int phy_init_hw(struct phy_device *phydev)
 {
         int ret;
@@ -504,12 +549,21 @@ int phy_init_hw(struct phy_device *phydev)
         if (!phydev->drv || !phydev->drv->config_init)
                 return 0;
 
+        ret = phy_write(phydev, MII_BMCR, BMCR_RESET);
+        if (ret < 0)
+                return ret;
+
+        ret = phy_poll_reset(phydev);
+        if (ret < 0)
+                return ret;
+
         ret = phy_scan_fixups(phydev);
         if (ret < 0)
                 return ret;
 
         return phydev->drv->config_init(phydev);
 }
+EXPORT_SYMBOL(phy_init_hw);
 
 /**
  * phy_attach_direct - attach a network device to a given PHY device pointer