net: dsa: qca8k: cache lo and hi for mdio write

From Documentation, we can cache lo and hi the same way we do with the
page. This massively reduce the mdio write as 3/4 of the time as we only
require to write the lo or hi part for a mdio write.

Signed-off-by: Ansuel Smith <ansuelsmth@gmail.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/dsa/qca8k.c b/drivers/net/dsa/qca8k.c
index 86d3742..0cce3a6 100644 (file)
--- a/drivers/net/dsa/qca8k.c
+++ b/drivers/net/dsa/qca8k.c
@@ -89,6 +89,44 @@ qca8k_split_addr(u32 regaddr, u16 *r1, u16 *r2, u16 *page)
 }
 
 static int
+qca8k_set_lo(struct qca8k_priv *priv, int phy_id, u32 regnum, u16 lo)
+{
+       u16 *cached_lo = &priv->mdio_cache.lo;
+       struct mii_bus *bus = priv->bus;
+       int ret;
+
+       if (lo == *cached_lo)
+               return 0;
+
+       ret = bus->write(bus, phy_id, regnum, lo);
+       if (ret < 0)
+               dev_err_ratelimited(&bus->dev,
+                                   "failed to write qca8k 32bit lo register\n");
+
+       *cached_lo = lo;
+       return 0;
+}
+
+static int
+qca8k_set_hi(struct qca8k_priv *priv, int phy_id, u32 regnum, u16 hi)
+{
+       u16 *cached_hi = &priv->mdio_cache.hi;
+       struct mii_bus *bus = priv->bus;
+       int ret;
+
+       if (hi == *cached_hi)
+               return 0;
+
+       ret = bus->write(bus, phy_id, regnum, hi);
+       if (ret < 0)
+               dev_err_ratelimited(&bus->dev,
+                                   "failed to write qca8k 32bit hi register\n");
+
+       *cached_hi = hi;
+       return 0;
+}
+
+static int
 qca8k_mii_read32(struct mii_bus *bus, int phy_id, u32 regnum, u32 *val)
 {
        int ret;
@@ -111,7 +149,7 @@ qca8k_mii_read32(struct mii_bus *bus, int phy_id, u32 regnum, u32 *val)
 }
 
 static void
-qca8k_mii_write32(struct mii_bus *bus, int phy_id, u32 regnum, u32 val)
+qca8k_mii_write32(struct qca8k_priv *priv, int phy_id, u32 regnum, u32 val)
 {
        u16 lo, hi;
        int ret;
@@ -119,12 +157,9 @@ qca8k_mii_write32(struct mii_bus *bus, int phy_id, u32 regnum, u32 val)
        lo = val & 0xffff;
        hi = (u16)(val >> 16);
 
-       ret = bus->write(bus, phy_id, regnum, lo);
+       ret = qca8k_set_lo(priv, phy_id, regnum, lo);
        if (ret >= 0)
-               ret = bus->write(bus, phy_id, regnum + 1, hi);
-       if (ret < 0)
-               dev_err_ratelimited(&bus->dev,
-                                   "failed to write qca8k 32bit register\n");
+               ret = qca8k_set_hi(priv, phy_id, regnum + 1, hi);
 }
 
 static int
@@ -400,7 +435,7 @@ qca8k_regmap_write(void *ctx, uint32_t reg, uint32_t val)
        if (ret < 0)
                goto exit;
 
-       qca8k_mii_write32(bus, 0x10 | r2, r1, val);
+       qca8k_mii_write32(priv, 0x10 | r2, r1, val);
 
 exit:
        mutex_unlock(&bus->mdio_lock);
@@ -433,7 +468,7 @@ qca8k_regmap_update_bits(void *ctx, uint32_t reg, uint32_t mask, uint32_t write_
 
        val &= ~mask;
        val |= write_val;
-       qca8k_mii_write32(bus, 0x10 | r2, r1, val);
+       qca8k_mii_write32(priv, 0x10 | r2, r1, val);
 
 exit:
        mutex_unlock(&bus->mdio_lock);
@@ -1117,14 +1152,14 @@ qca8k_mdio_write(struct qca8k_priv *priv, int phy, int regnum, u16 data)
        if (ret)
                goto exit;
 
-       qca8k_mii_write32(bus, 0x10 | r2, r1, val);
+       qca8k_mii_write32(priv, 0x10 | r2, r1, val);
 
        ret = qca8k_mdio_busy_wait(bus, QCA8K_MDIO_MASTER_CTRL,
                                   QCA8K_MDIO_MASTER_BUSY);
 
 exit:
        /* even if the busy_wait timeouts try to clear the MASTER_EN */
-       qca8k_mii_write32(bus, 0x10 | r2, r1, 0);
+       qca8k_mii_write32(priv, 0x10 | r2, r1, 0);
 
        mutex_unlock(&bus->mdio_lock);
 
@@ -1154,7 +1189,7 @@ qca8k_mdio_read(struct qca8k_priv *priv, int phy, int regnum)
        if (ret)
                goto exit;
 
-       qca8k_mii_write32(bus, 0x10 | r2, r1, val);
+       qca8k_mii_write32(priv, 0x10 | r2, r1, val);
 
        ret = qca8k_mdio_busy_wait(bus, QCA8K_MDIO_MASTER_CTRL,
                                   QCA8K_MDIO_MASTER_BUSY);
@@ -1165,7 +1200,7 @@ qca8k_mdio_read(struct qca8k_priv *priv, int phy, int regnum)
 
 exit:
        /* even if the busy_wait timeouts try to clear the MASTER_EN */
-       qca8k_mii_write32(bus, 0x10 | r2, r1, 0);
+       qca8k_mii_write32(priv, 0x10 | r2, r1, 0);
 
        mutex_unlock(&bus->mdio_lock);
 
@@ -3039,6 +3074,8 @@ qca8k_sw_probe(struct mdio_device *mdiodev)
        }
 
        priv->mdio_cache.page = 0xffff;
+       priv->mdio_cache.lo = 0xffff;
+       priv->mdio_cache.hi = 0xffff;
 
        /* Check the detected switch id */
        ret = qca8k_read_switch_id(priv);

diff --git a/drivers/net/dsa/qca8k.h b/drivers/net/dsa/qca8k.h
index 57368ac..c3d3c22 100644 (file)
--- a/drivers/net/dsa/qca8k.h
+++ b/drivers/net/dsa/qca8k.h
@@ -369,6 +369,11 @@ struct qca8k_mdio_cache {
  * mdio writes
  */
        u16 page;
+/* lo and hi can also be cached and from Documentation we can skip one
+ * extra mdio write if lo or hi is didn't change.
+ */
+       u16 lo;
+       u16 hi;
 };
 
 struct qca8k_priv {