net: cpsw: Loop until interface ready or timeout in cpsw_slave_update_link()

Without this patch the first packet sent will always be dropped.

Also check for interface status in cpsw_send() only if interface is
not ready because the MII access inside cpsw_update_link() is a very
time consuming operation and significantly deteriorates performance.

diff --git a/drivers/net/cpsw.c b/drivers/net/cpsw.c
index 1f305d2819484670b1465bdaade2bfb9c8d42ab0..0add7cf5b1eeebd3a2d395879a8453643677456d 100644 (file)
--- a/drivers/net/cpsw.c
+++ b/drivers/net/cpsw.c
@@ -559,6 +559,7 @@ static void cpsw_set_slave_mac(struct cpsw_slave *slave,
        __raw_writel(mac_lo(priv->dev->enetaddr), &slave->regs->sa_lo);
 }
 
        __raw_writel(mac_lo(priv->dev->enetaddr), &slave->regs->sa_lo);
 }
 

+#define NUM_TRIES 50

 static void cpsw_slave_update_link(struct cpsw_slave *slave,
                                   struct cpsw_priv *priv, int *link)
 {
 static void cpsw_slave_update_link(struct cpsw_slave *slave,
                                   struct cpsw_priv *priv, int *link)
 {


@@ -567,37 +568,42 @@ static void cpsw_slave_update_link(struct cpsw_slave *slave,
        int speed, duplex;
        unsigned short reg;
        u32 mac_control = 0;
        int speed, duplex;
        unsigned short reg;
        u32 mac_control = 0;

+       int retries = NUM_TRIES;

 
 

-       if (miiphy_read(name, phy_id, MII_BMSR, &reg)) {
-               printf("Failed to read PHY reg\n");
-               return; /* could not read, assume no link */
-       }
+       while (retries-- > 0) {
+               if (miiphy_read(name, phy_id, MII_BMSR, &reg)) {
+                       printf("Failed to read PHY reg\n");
+                       return; /* could not read, assume no link */
+               }

 
 

-       if (reg & BMSR_LSTATUS) { /* link up */
-               speed = miiphy_speed(name, phy_id);
-               duplex = miiphy_duplex(name, phy_id);
-
-               *link = 1;
-               mac_control = priv->data->mac_control;
-               if (speed == 10)
-                       mac_control |= BIT(18); /* In Band mode */
-               else if (speed == 100)
-                       mac_control |= BIT(15);
-               else if (speed == 1000) {
-                       if (priv->data->gigabit_en)
-                               mac_control |= BIT(7);
-                       else {
-                               /* Disable gigabit as it's non-functional */
-                               mac_control &= ~BIT(7);
-                               speed = 100;
+               if (reg & BMSR_LSTATUS) { /* link up */
+                       speed = miiphy_speed(name, phy_id);
+                       duplex = miiphy_duplex(name, phy_id);
+
+                       *link = 1;
+                       mac_control = priv->data->mac_control;
+                       if (speed == 10)
+                               mac_control |= BIT(18); /* In Band mode */
+                       else if (speed == 100)
+                               mac_control |= BIT(15);
+                       else if (speed == 1000) {
+                               if (priv->data->gigabit_en)
+                                       mac_control |= BIT(7);
+                               else {
+                                       /* Disable gigabit as it's non-functional */
+                                       mac_control &= ~BIT(7);
+                                       speed = 100;
+                               }

                        }
                        }

-               }

 
 

-               if (duplex == FULL)
-                       mac_control |= BIT(0);  /* FULLDUPLEXEN */
+                       if (duplex == FULL)
+                               mac_control |= BIT(0);  /* FULLDUPLEXEN */
+                       break;
+               }
+               udelay(100000);

        }
        }

-       debug("%s: mac_control: %08x -> %08x\n", __func__,
-               slave->mac_control, mac_control);
+       debug("%s: mac_control: %08x -> %08x after %u loops\n", __func__,
+               slave->mac_control, mac_control, NUM_TRIES - retries);

 
        if (mac_control == slave->mac_control)
                return;
 
        if (mac_control == slave->mac_control)
                return;


@@ -901,7 +907,9 @@ static int cpsw_send(struct eth_device *dev, volatile void *packet, int length)
 
        debug("%s@%d: sending packet %p..%p\n", __func__, __LINE__,
                packet, packet + length - 1);
 
        debug("%s@%d: sending packet %p..%p\n", __func__, __LINE__,
                packet, packet + length - 1);

-       if (!cpsw_update_link(priv))
+
+       if (!priv->data->mac_control && !cpsw_update_link(priv)) {
+               printf("%s: Cannot send packet; link is down\n", __func__);

                return -EIO;
        }
 
                return -EIO;
        }