From 21dd19fed3c3eb42a3877600f4a97a774323e562 Mon Sep 17 00:00:00 2001 From: Neil Armstrong Date: Thu, 22 Oct 2015 10:37:49 +0200 Subject: [PATCH] net: phy: Add nested variants of mdiobus read/write Since nested variants of mdiobus_read/write are used in multiple drivers, add nested variants in the mdiobus core. Suggested-by: Andrew Lunn Signed-off-by: Neil Armstrong Signed-off-by: David S. Miller --- drivers/net/phy/mdio_bus.c | 55 ++++++++++++++++++++++++++++++++++++++ include/linux/phy.h | 2 ++ 2 files changed, 57 insertions(+) diff --git a/drivers/net/phy/mdio_bus.c b/drivers/net/phy/mdio_bus.c index 12f44c53cc8e..88cb4592b6fb 100644 --- a/drivers/net/phy/mdio_bus.c +++ b/drivers/net/phy/mdio_bus.c @@ -371,6 +371,33 @@ struct phy_device *mdiobus_scan(struct mii_bus *bus, int addr) } EXPORT_SYMBOL(mdiobus_scan); +/** + * mdiobus_read_nested - Nested version of the mdiobus_read function + * @bus: the mii_bus struct + * @addr: the phy address + * @regnum: register number to read + * + * In case of nested MDIO bus access avoid lockdep false positives by + * using mutex_lock_nested(). + * + * NOTE: MUST NOT be called from interrupt context, + * because the bus read/write functions may wait for an interrupt + * to conclude the operation. + */ +int mdiobus_read_nested(struct mii_bus *bus, int addr, u32 regnum) +{ + int retval; + + BUG_ON(in_interrupt()); + + mutex_lock_nested(&bus->mdio_lock, SINGLE_DEPTH_NESTING); + retval = bus->read(bus, addr, regnum); + mutex_unlock(&bus->mdio_lock); + + return retval; +} +EXPORT_SYMBOL(mdiobus_read_nested); + /** * mdiobus_read - Convenience function for reading a given MII mgmt register * @bus: the mii_bus struct @@ -395,6 +422,34 @@ int mdiobus_read(struct mii_bus *bus, int addr, u32 regnum) } EXPORT_SYMBOL(mdiobus_read); +/** + * mdiobus_write_nested - Nested version of the mdiobus_write function + * @bus: the mii_bus struct + * @addr: the phy address + * @regnum: register number to write + * @val: value to write to @regnum + * + * In case of nested MDIO bus access avoid lockdep false positives by + * using mutex_lock_nested(). + * + * NOTE: MUST NOT be called from interrupt context, + * because the bus read/write functions may wait for an interrupt + * to conclude the operation. + */ +int mdiobus_write_nested(struct mii_bus *bus, int addr, u32 regnum, u16 val) +{ + int err; + + BUG_ON(in_interrupt()); + + mutex_lock_nested(&bus->mdio_lock, SINGLE_DEPTH_NESTING); + err = bus->write(bus, addr, regnum, val); + mutex_unlock(&bus->mdio_lock); + + return err; +} +EXPORT_SYMBOL(mdiobus_write_nested); + /** * mdiobus_write - Convenience function for writing a given MII mgmt register * @bus: the mii_bus struct diff --git a/include/linux/phy.h b/include/linux/phy.h index 4c477e6ece33..05fde31b6dc6 100644 --- a/include/linux/phy.h +++ b/include/linux/phy.h @@ -213,7 +213,9 @@ static inline struct mii_bus *devm_mdiobus_alloc(struct device *dev) void devm_mdiobus_free(struct device *dev, struct mii_bus *bus); struct phy_device *mdiobus_scan(struct mii_bus *bus, int addr); int mdiobus_read(struct mii_bus *bus, int addr, u32 regnum); +int mdiobus_read_nested(struct mii_bus *bus, int addr, u32 regnum); int mdiobus_write(struct mii_bus *bus, int addr, u32 regnum, u16 val); +int mdiobus_write_nested(struct mii_bus *bus, int addr, u32 regnum, u16 val); #define PHY_INTERRUPT_DISABLED 0x0 -- 2.20.1