[PATCH 10/14] drivers: net: dsa: qca8k: add support for specific QCA access function

[Ansuel Smith <ansuelsmth@gmail.com>]

Some qca8k switch revision require some special dbg value to be set
based on the revision number. Add required function to write and read in
these specific registers.

Signed-off-by: Ansuel Smith <ansuelsmth@gmail.com>
---
 drivers/net/dsa/qca8k.c | 51 +++++++++++++++++++++++++++++++++++++++++
 drivers/net/dsa/qca8k.h |  2 ++
 2 files changed, 53 insertions(+)

diff --git a/drivers/net/dsa/qca8k.c b/drivers/net/dsa/qca8k.c
index 20b507a35191..193c269d8ed3 100644
--- a/drivers/net/dsa/qca8k.c
+++ b/drivers/net/dsa/qca8k.c
@@ -69,6 +69,57 @@ static const struct qca8k_mib_desc ar8327_mib[] = {
 	MIB_DESC(1, 0xa4, "TxLateCol"),
 };
 
+/* QCA specific MII registers access function */
+void qca8k_phy_dbg_read(struct qca8k_priv *priv, int phy_addr, u16 dbg_addr, u16 *dbg_data)
+{
+	struct mii_bus *bus = priv->bus;
+
+	mutex_lock_nested(&bus->mdio_lock, MDIO_MUTEX_NESTED);
+	bus->write(bus, phy_addr, MII_ATH_DBG_ADDR, dbg_addr);
+	*dbg_data = bus->read(bus, phy_addr, MII_ATH_DBG_DATA);
+	mutex_unlock(&bus->mdio_lock);
+}
+
+void qca8k_phy_dbg_write(struct qca8k_priv *priv, int phy_addr, u16 dbg_addr, u16 dbg_data)
+{
+	struct mii_bus *bus = priv->bus;
+
+	mutex_lock_nested(&bus->mdio_lock, MDIO_MUTEX_NESTED);
+	bus->write(bus, phy_addr, MII_ATH_DBG_ADDR, dbg_addr);
+	bus->write(bus, phy_addr, MII_ATH_DBG_DATA, dbg_data);
+	mutex_unlock(&bus->mdio_lock);
+}
+
+static inline void qca8k_phy_mmd_prep(struct mii_bus *bus, int phy_addr, u16 addr, u16 reg)
+{
+	bus->write(bus, phy_addr, MII_ATH_MMD_ADDR, addr);
+	bus->write(bus, phy_addr, MII_ATH_MMD_DATA, reg);
+	bus->write(bus, phy_addr, MII_ATH_MMD_ADDR, addr | 0x4000);
+}
+
+void qca8k_phy_mmd_write(struct qca8k_priv *priv, int phy_addr, u16 addr, u16 reg, u16 data)
+{
+	struct mii_bus *bus = priv->bus;
+
+	mutex_lock_nested(&bus->mdio_lock, MDIO_MUTEX_NESTED);
+	qca8k_phy_mmd_prep(bus, phy_addr, addr, reg);
+	bus->write(bus, phy_addr, MII_ATH_MMD_DATA, data);
+	mutex_unlock(&bus->mdio_lock);
+}
+
+u16 qca8k_phy_mmd_read(struct qca8k_priv *priv, int phy_addr, u16 addr, u16 reg)
+{
+	struct mii_bus *bus = priv->bus;
+	u16 data;
+
+	mutex_lock_nested(&bus->mdio_lock, MDIO_MUTEX_NESTED);
+	qca8k_phy_mmd_prep(bus, phy_addr, addr, reg);
+	data = bus->read(bus, phy_addr, MII_ATH_MMD_DATA);
+	mutex_unlock(&bus->mdio_lock);
+
+	return data;
+}
+
 /* The 32bit switch registers are accessed indirectly. To achieve this we need
  * to set the page of the register. Track the last page that was set to reduce
  * mdio writes
diff --git a/drivers/net/dsa/qca8k.h b/drivers/net/dsa/qca8k.h
index dbd54d870a30..de00aa74868b 100644
--- a/drivers/net/dsa/qca8k.h
+++ b/drivers/net/dsa/qca8k.h
@@ -215,6 +215,8 @@
 /* QCA specific MII registers */
 #define MII_ATH_MMD_ADDR				0x0d
 #define MII_ATH_MMD_DATA				0x0e
+#define MII_ATH_DBG_ADDR				0x1d
+#define MII_ATH_DBG_DATA				0x1e
 
 enum {
 	QCA8K_PORT_SPEED_10M = 0,
-- 
2.30.2