1 files changed, 109 insertions, 6 deletions

diff --git a/drivers/net/ethernet/freescale/enetc/enetc_hw.h b/drivers/net/ethernet/freescale/enetc/enetc_hw.h
index 68ef4f959982..861bd04638e0 100644
--- a/drivers/net/ethernet/freescale/enetc/enetc_hw.h
+++ b/drivers/net/ethernet/freescale/enetc/enetc_hw.h
@@ -324,14 +324,100 @@ struct enetc_hw {
 	void __iomem *global;
 };
 
-/* general register accessors */
-#define enetc_rd_reg(reg)	ioread32((reg))
-#define enetc_wr_reg(reg, val)	iowrite32((val), (reg))
+/* ENETC register accessors */
+
+/* MDIO issue workaround (on LS1028A) -
+ * Due to a hardware issue, an access to MDIO registers
+ * that is concurrent with other ENETC register accesses
+ * may lead to the MDIO access being dropped or corrupted.
+ * To protect the MDIO accesses a readers-writers locking
+ * scheme is used, where the MDIO register accesses are
+ * protected by write locks to insure exclusivity, while
+ * the remaining ENETC registers are accessed under read
+ * locks since they only compete with MDIO accesses.
+ */
+extern rwlock_t enetc_mdio_lock;
+
+/* use this locking primitive only on the fast datapath to
+ * group together multiple non-MDIO register accesses to
+ * minimize the overhead of the lock
+ */
+static inline void enetc_lock_mdio(void)
+{
+	read_lock(&enetc_mdio_lock);
+}
+
+static inline void enetc_unlock_mdio(void)
+{
+	read_unlock(&enetc_mdio_lock);
+}
+
+/* use these accessors only on the fast datapath under
+ * the enetc_lock_mdio() locking primitive to minimize
+ * the overhead of the lock
+ */
+static inline u32 enetc_rd_reg_hot(void __iomem *reg)
+{
+	lockdep_assert_held(&enetc_mdio_lock);
+
+	return ioread32(reg);
+}
+
+static inline void enetc_wr_reg_hot(void __iomem *reg, u32 val)
+{
+	lockdep_assert_held(&enetc_mdio_lock);
+
+	iowrite32(val, reg);
+}
+
+/* internal helpers for the MDIO w/a */
+static inline u32 _enetc_rd_reg_wa(void __iomem *reg)
+{
+	u32 val;
+
+	enetc_lock_mdio();
+	val = ioread32(reg);
+	enetc_unlock_mdio();
+
+	return val;
+}
+
+static inline void _enetc_wr_reg_wa(void __iomem *reg, u32 val)
+{
+	enetc_lock_mdio();
+	iowrite32(val, reg);
+	enetc_unlock_mdio();
+}
+
+static inline u32 _enetc_rd_mdio_reg_wa(void __iomem *reg)
+{
+	unsigned long flags;
+	u32 val;
+
+	write_lock_irqsave(&enetc_mdio_lock, flags);
+	val = ioread32(reg);
+	write_unlock_irqrestore(&enetc_mdio_lock, flags);
+
+	return val;
+}
+
+static inline void _enetc_wr_mdio_reg_wa(void __iomem *reg, u32 val)
+{
+	unsigned long flags;
+
+	write_lock_irqsave(&enetc_mdio_lock, flags);
+	iowrite32(val, reg);
+	write_unlock_irqrestore(&enetc_mdio_lock, flags);
+}
+
 #ifdef ioread64
-#define enetc_rd_reg64(reg)	ioread64((reg))
+static inline u64 _enetc_rd_reg64(void __iomem *reg)
+{
+	return ioread64(reg);
+}
 #else
 /* using this to read out stats on 32b systems */
-static inline u64 enetc_rd_reg64(void __iomem *reg)
+static inline u64 _enetc_rd_reg64(void __iomem *reg)
 {
 	u32 low, high, tmp;
 
@@ -345,12 +431,29 @@ static inline u64 enetc_rd_reg64(void __iomem *reg)
 }
 #endif
 
+static inline u64 _enetc_rd_reg64_wa(void __iomem *reg)
+{
+	u64 val;
+
+	enetc_lock_mdio();
+	val = _enetc_rd_reg64(reg);
+	enetc_unlock_mdio();
+
+	return val;
+}
+
+/* general register accessors */
+#define enetc_rd_reg(reg)		_enetc_rd_reg_wa((reg))
+#define enetc_wr_reg(reg, val)		_enetc_wr_reg_wa((reg), (val))
 #define enetc_rd(hw, off)		enetc_rd_reg((hw)->reg + (off))
 #define enetc_wr(hw, off, val)		enetc_wr_reg((hw)->reg + (off), val)
-#define enetc_rd64(hw, off)		enetc_rd_reg64((hw)->reg + (off))
+#define enetc_rd64(hw, off)		_enetc_rd_reg64_wa((hw)->reg + (off))
 /* port register accessors - PF only */
 #define enetc_port_rd(hw, off)		enetc_rd_reg((hw)->port + (off))
 #define enetc_port_wr(hw, off, val)	enetc_wr_reg((hw)->port + (off), val)
+#define enetc_port_rd_mdio(hw, off)	_enetc_rd_mdio_reg_wa((hw)->port + (off))
+#define enetc_port_wr_mdio(hw, off, val)	_enetc_wr_mdio_reg_wa(\
+							(hw)->port + (off), val)
 /* global register accessors - PF only */
 #define enetc_global_rd(hw, off)	enetc_rd_reg((hw)->global + (off))
 #define enetc_global_wr(hw, off, val)	enetc_wr_reg((hw)->global + (off), val)