net: phy: fix resume handling

[ Upstream commit f5e64032a799d4f54decc7eb6aafcdffb67f9ad9 ]

When a PHY has the BMCR_PDOWN bit set, it may decide to ignore writes
to other registers, or reset the registers to power-on defaults.
Micrel PHYs do this for their interrupt registers.

The current structure of phylib tries to enable interrupts before
resuming (and releasing) the BMCR_PDOWN bit.  This fails, causing
Micrel PHYs to stop working after a suspend/resume sequence if they
are using interrupts.

Fix this by ensuring that the PHY driver resume methods do not take
the phydev->lock mutex themselves, but the callers of phy_resume()
take that lock.  This then allows us to move the call to phy_resume()
before we enable interrupts in phy_start().

Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/net/phy/at803x.c b/drivers/net/phy/at803x.c
index 5f93e6add56394f28f68da72ddb8fc724db14200..e911e4990b20e181aaf3711d1069f086c2a7a4d3 100644 (file)
--- a/drivers/net/phy/at803x.c
+++ b/drivers/net/phy/at803x.c
@@ -239,14 +239,10 @@ static int at803x_resume(struct phy_device *phydev)
 {
        int value;
 
-       mutex_lock(&phydev->lock);
-
        value = phy_read(phydev, MII_BMCR);
        value &= ~(BMCR_PDOWN | BMCR_ISOLATE);
        phy_write(phydev, MII_BMCR, value);
 
-       mutex_unlock(&phydev->lock);
-
        return 0;
 }
 

diff --git a/drivers/net/phy/phy.c b/drivers/net/phy/phy.c
index 3d860de5e342b2c9a5d6bbe239e09b7debfd1636..26ad88f09795336e4e547d2da9505c4d18d04792 100644 (file)
--- a/drivers/net/phy/phy.c
+++ b/drivers/net/phy/phy.c
@@ -828,7 +828,6 @@ EXPORT_SYMBOL(phy_stop);
  */
 void phy_start(struct phy_device *phydev)
 {
-       bool do_resume = false;
        int err = 0;
 
        mutex_lock(&phydev->lock);
@@ -841,6 +840,9 @@ void phy_start(struct phy_device *phydev)
                phydev->state = PHY_UP;
                break;
        case PHY_HALTED:
+               /* if phy was suspended, bring the physical link up again */
+               phy_resume(phydev);
+
                /* make sure interrupts are re-enabled for the PHY */
                if (phy_interrupt_is_valid(phydev)) {
                        err = phy_enable_interrupts(phydev);
@@ -849,17 +851,12 @@ void phy_start(struct phy_device *phydev)
                }
 
                phydev->state = PHY_RESUMING;
-               do_resume = true;
                break;
        default:
                break;
        }
        mutex_unlock(&phydev->lock);
 
-       /* if phy was suspended, bring the physical link up again */
-       if (do_resume)
-               phy_resume(phydev);
-
        phy_trigger_machine(phydev, true);
 }
 EXPORT_SYMBOL(phy_start);

diff --git a/drivers/net/phy/phy_device.c b/drivers/net/phy/phy_device.c
index 67f25ac29025c53903cc724fac62efdd94828510..b15b31ca26182719cca6f764e19335483e11930e 100644 (file)
--- a/drivers/net/phy/phy_device.c
+++ b/drivers/net/phy/phy_device.c
@@ -135,7 +135,9 @@ static int mdio_bus_phy_resume(struct device *dev)
        if (!mdio_bus_phy_may_suspend(phydev))
                goto no_resume;
 
+       mutex_lock(&phydev->lock);
        ret = phy_resume(phydev);
+       mutex_unlock(&phydev->lock);
        if (ret < 0)
                return ret;
 
@@ -1026,7 +1028,9 @@ int phy_attach_direct(struct net_device *dev, struct phy_device *phydev,
        if (err)
                goto error;
 
+       mutex_lock(&phydev->lock);
        phy_resume(phydev);
+       mutex_unlock(&phydev->lock);
        phy_led_triggers_register(phydev);
 
        return err;
@@ -1157,6 +1161,8 @@ int phy_resume(struct phy_device *phydev)
        struct phy_driver *phydrv = to_phy_driver(phydev->mdio.dev.driver);
        int ret = 0;
 
+       WARN_ON(!mutex_is_locked(&phydev->lock));
+
        if (phydev->drv && phydrv->resume)
                ret = phydrv->resume(phydev);
 
@@ -1639,13 +1645,9 @@ int genphy_resume(struct phy_device *phydev)
 {
        int value;
 
-       mutex_lock(&phydev->lock);
-
        value = phy_read(phydev, MII_BMCR);
        phy_write(phydev, MII_BMCR, value & ~BMCR_PDOWN);
 
-       mutex_unlock(&phydev->lock);
-
        return 0;
 }
 EXPORT_SYMBOL(genphy_resume);