From 788f9933db6172801336d0ae2dec5bdc7525389f Mon Sep 17 00:00:00 2001
From: Russell King <rmk+kernel@armlinux.org.uk>
Date: Tue, 2 Jan 2018 10:58:37 +0000
Subject: [PATCH] net: phy: add unlocked accessors
Git-commit: 788f9933db6172801336d0ae2dec5bdc7525389f
Patch-mainline: v4.16-rc1
References: bsc#1085262

Add unlocked versions of the bus accessors, which allows access to the
bus with all the tracing. These accessors validate that the bus mutex
is held, which is a basic requirement for all mii bus accesses.

Also added is a read-modify-write unlocked accessor with the same
locking requirements.

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>
Acked-by: Takashi Iwai <tiwai@suse.de>

---
 drivers/net/phy/phy-core.c | 25 +++++++++++++++++++++++++
 include/linux/phy.h        | 28 ++++++++++++++++++++++++++++
 2 files changed, 53 insertions(+)

diff --git a/drivers/net/phy/phy-core.c b/drivers/net/phy/phy-core.c
index 2c985c6e2cdd..028c098e9a00 100644
--- a/drivers/net/phy/phy-core.c
+++ b/drivers/net/phy/phy-core.c
@@ -323,3 +323,28 @@ int phy_write_mmd(struct phy_device *phydev, int devad, u32 regnum, u16 val)
 	return ret;
 }
 EXPORT_SYMBOL(phy_write_mmd);
+
+/**
+ * __phy_modify() - Convenience function for modifying a PHY register
+ * @phydev: a pointer to a &struct phy_device
+ * @regnum: register number
+ * @mask: bit mask of bits to clear
+ * @set: bit mask of bits to set
+ *
+ * Unlocked helper function which allows a PHY register to be modified as
+ * new register value = (old register value & mask) | set
+ */
+int __phy_modify(struct phy_device *phydev, u32 regnum, u16 mask, u16 set)
+{
+	int ret, res;
+
+	ret = __phy_read(phydev, regnum);
+	if (ret >= 0) {
+		res = __phy_write(phydev, regnum, (ret & ~mask) | set);
+		if (res < 0)
+			ret = res;
+	}
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(__phy_modify);
diff --git a/include/linux/phy.h b/include/linux/phy.h
index a052e3768422..0c5a28520c65 100644
--- a/include/linux/phy.h
+++ b/include/linux/phy.h
@@ -717,6 +717,18 @@ static inline int phy_read(struct phy_device *phydev, u32 regnum)
 	return mdiobus_read(phydev->mdio.bus, phydev->mdio.addr, regnum);
 }
 
+/**
+ * __phy_read - convenience function for reading a given PHY register
+ * @phydev: the phy_device struct
+ * @regnum: register number to read
+ *
+ * The caller must have taken the MDIO bus lock.
+ */
+static inline int __phy_read(struct phy_device *phydev, u32 regnum)
+{
+	return __mdiobus_read(phydev->mdio.bus, phydev->mdio.addr, regnum);
+}
+
 /**
  * phy_write - Convenience function for writing a given PHY register
  * @phydev: the phy_device struct
@@ -732,6 +744,22 @@ static inline int phy_write(struct phy_device *phydev, u32 regnum, u16 val)
 	return mdiobus_write(phydev->mdio.bus, phydev->mdio.addr, regnum, val);
 }
 
+/**
+ * __phy_write - Convenience function for writing a given PHY register
+ * @phydev: the phy_device struct
+ * @regnum: register number to write
+ * @val: value to write to @regnum
+ *
+ * The caller must have taken the MDIO bus lock.
+ */
+static inline int __phy_write(struct phy_device *phydev, u32 regnum, u16 val)
+{
+	return __mdiobus_write(phydev->mdio.bus, phydev->mdio.addr, regnum,
+			       val);
+}
+
+int __phy_modify(struct phy_device *phydev, u32 regnum, u16 mask, u16 set);
+
 /**
  * phy_interrupt_is_valid - Convenience function for testing a given PHY irq
  * @phydev: the phy_device struct
-- 
2.18.0