net: phy: improve phy state checking

Add helpers phy_is_started() and __phy_is_started() to avoid open-coded
checks whether PHY has been started. To make the check easier move
PHY_HALTED before PHY_UP in enum phy_state. Further improvements:

phy_start_aneg():
Return -EBUSY and print warning if function is called from a non-started
state (DOWN, READY, HALTED). Better check because function is exported
and drivers may use it incorrectly.

phy_interrupt():
Return IRQ_NONE also if state is DOWN or READY. We should never receive
an interrupt in one of these states, but better play safe.

phy_stop():
Just return and print a warning if PHY is in a non-started state.
This warning should help to identify drivers with unbalanced calls to
phy_start() / phy_stop().

phy_state_machine():
Schedule state machine run only if PHY is in a started state.
E.g. if state is READY we don't need the state machine, it will be
started by phy_start().

v2:
- don't use __func__ within phy_warn_state
v3:
- use WARN() instead of printing error message to facilitate debugging

Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 23 insertions, 1 deletions

diff --git a/include/linux/phy.h b/include/linux/phy.h
index 8f927246acdb..da039f211c22 100644
--- a/include/linux/phy.h
+++ b/include/linux/phy.h
@@ -319,12 +319,12 @@ struct phy_device *mdiobus_scan(struct mii_bus *bus, int addr);
 enum phy_state {
 	PHY_DOWN = 0,
 	PHY_READY,
+	PHY_HALTED,
 	PHY_UP,
 	PHY_RUNNING,
 	PHY_NOLINK,
 	PHY_FORCING,
 	PHY_CHANGELINK,
-	PHY_HALTED,
 	PHY_RESUMING
 };
 
@@ -669,6 +669,28 @@ phy_lookup_setting(int speed, int duplex, const unsigned long *mask,
 size_t phy_speeds(unsigned int *speeds, size_t size,
 		  unsigned long *mask);
 
+static inline bool __phy_is_started(struct phy_device *phydev)
+{
+	WARN_ON(!mutex_is_locked(&phydev->lock));
+
+	return phydev->state >= PHY_UP;
+}
+
+/**
+ * phy_is_started - Convenience function to check whether PHY is started
+ * @phydev: The phy_device struct
+ */
+static inline bool phy_is_started(struct phy_device *phydev)
+{
+	bool started;
+
+	mutex_lock(&phydev->lock);
+	started = __phy_is_started(phydev);
+	mutex_unlock(&phydev->lock);
+
+	return started;
+}
+
 void phy_resolve_aneg_linkmode(struct phy_device *phydev);
 
 /**