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net: phy: fix resume handling

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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>
This commit is contained in:
Russell King 2017-12-12 10:45:36 +00:00 committed by David S. Miller
parent cd8165c3d5
commit f5e64032a7
3 changed files with 9 additions and 14 deletions
repo.diff.show_diff_stats Download patch file Download diff file Expand all files Collapse all files

4
drivers/net/phy/at803x.c
View file

@ -239,14 +239,10 @@ static int at803x_resume(struct phy_device *phydev)
{ {
int value; int value;
mutex_lock(&phydev->lock);
value = phy_read(phydev, MII_BMCR); value = phy_read(phydev, MII_BMCR);
value &= ~(BMCR_PDOWN | BMCR_ISOLATE); value &= ~(BMCR_PDOWN | BMCR_ISOLATE);
phy_write(phydev, MII_BMCR, value); phy_write(phydev, MII_BMCR, value);
mutex_unlock(&phydev->lock);
return 0; return 0;
} }

9
drivers/net/phy/phy.c
View file

@ -828,7 +828,6 @@ EXPORT_SYMBOL(phy_stop);
*/ */
void phy_start(struct phy_device *phydev) void phy_start(struct phy_device *phydev)
{ {
bool do_resume = false;
int err = 0; int err = 0;
mutex_lock(&phydev->lock); mutex_lock(&phydev->lock);
@ -841,6 +840,9 @@ void phy_start(struct phy_device *phydev)
phydev->state = PHY_UP; phydev->state = PHY_UP;
break; break;
case PHY_HALTED: 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 */ /* make sure interrupts are re-enabled for the PHY */
if (phydev->irq != PHY_POLL) { if (phydev->irq != PHY_POLL) {
err = phy_enable_interrupts(phydev); err = phy_enable_interrupts(phydev);
@ -849,17 +851,12 @@ void phy_start(struct phy_device *phydev)
} }
phydev->state = PHY_RESUMING; phydev->state = PHY_RESUMING;
do_resume = true;
break; break;
default: default:
break; break;
} }
mutex_unlock(&phydev->lock); 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); phy_trigger_machine(phydev, true);
} }
EXPORT_SYMBOL(phy_start); EXPORT_SYMBOL(phy_start);

10
drivers/net/phy/phy_device.c
View file

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