net: systemport: fix UniMAC reset logic

The UniMAC CMD_SW_RESET bit is not a self-clearing bit, so we need to
assert it, wait a bit and clear it manually. As a result, umac_reset()
is updated not to return any value. The previous version of the code
simply wrote 0 to the CMD register, which would make the busy-waiting
loop exit immediately, having zero effect.

By writing 0 to the CMD register, we were clearing all bits in the CMD
register, and not using the hardware reset default values which are
set on purpose.

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

diff --git a/drivers/net/ethernet/broadcom/bcmsysport.c b/drivers/net/ethernet/broadcom/bcmsysport.c
index f6bccd847ee6bdd4c03d0a47731f48758856f54c..d31f7d239064cd80ca47443f1d9c6f891d5aaf8a 100644 (file)
--- a/drivers/net/ethernet/broadcom/bcmsysport.c
+++ b/drivers/net/ethernet/broadcom/bcmsysport.c
@@ -1254,28 +1254,17 @@ static inline void umac_enable_set(struct bcm_sysport_priv *priv,
                usleep_range(1000, 2000);
 }
 
-static inline int umac_reset(struct bcm_sysport_priv *priv)
+static inline void umac_reset(struct bcm_sysport_priv *priv)
 {
-       unsigned int timeout = 0;
        u32 reg;
-       int ret = 0;
-
-       umac_writel(priv, 0, UMAC_CMD);
-       while (timeout++ < 1000) {
-               reg = umac_readl(priv, UMAC_CMD);
-               if (!(reg & CMD_SW_RESET))
-                       break;
-
-               udelay(1);
-       }
-
-       if (timeout == 1000) {
-               dev_err(&priv->pdev->dev,
-                       "timeout waiting for MAC to come out of reset\n");
-               ret = -ETIMEDOUT;
-       }
 
-       return ret;
+       reg = umac_readl(priv, UMAC_CMD);
+       reg |= CMD_SW_RESET;
+       umac_writel(priv, reg, UMAC_CMD);
+       udelay(10);
+       reg = umac_readl(priv, UMAC_CMD);
+       reg &= ~CMD_SW_RESET;
+       umac_writel(priv, reg, UMAC_CMD);
 }
 
 static void umac_set_hw_addr(struct bcm_sysport_priv *priv,
@@ -1303,11 +1292,7 @@ static int bcm_sysport_open(struct net_device *dev)
        int ret;
 
        /* Reset UniMAC */
-       ret = umac_reset(priv);
-       if (ret) {
-               netdev_err(dev, "UniMAC reset failed\n");
-               return ret;
-       }
+       umac_reset(priv);
 
        /* Flush TX and RX FIFOs at TOPCTRL level */
        topctrl_flush(priv);