[PATCH net v2 04/12] net: au1000: report MDIO transaction timeouts

[Florian Fainelli <f.fainelli@gmail.com>]

The MDIO write callback reports success even if the controller stays
busy and no write is issued. Propagate timeout errors and wait for write
completion so failure of the final transaction is reported to phylib as
well. Return ETIMEDOUT for read timeouts too.

Use readl_poll_timeout() for write completion with a 20 microsecond sleep
interval and a 20 millisecond timeout. The MDIO callback runs in sleepable
context, so avoid adding millisecond busy-waits for completion.

Fixes: 0638dec01e89 ("[PATCH] net: au1000_eth: PHY framework conversion")
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
---
 drivers/net/ethernet/amd/au1000_eth.c | 22 +++++++++++++++-------
 1 file changed, 15 insertions(+), 7 deletions(-)

diff --git a/drivers/net/ethernet/amd/au1000_eth.c b/drivers/net/ethernet/amd/au1000_eth.c
index 7063f9e5bc7c..6b2e216a8361 100644
--- a/drivers/net/ethernet/amd/au1000_eth.c
+++ b/drivers/net/ethernet/amd/au1000_eth.c
@@ -41,6 +41,7 @@
 #include <linux/platform_device.h>
 #include <linux/cpu.h>
 #include <linux/io.h>
+#include <linux/iopoll.h>
 
 #include <asm/mipsregs.h>
 #include <asm/irq.h>
@@ -278,7 +279,7 @@ static int au1000_mdio_read(struct net_device *dev, int phy_addr, int reg)
 		mdelay(1);
 		if (--timedout == 0) {
 			netdev_err(dev, "read_MII busy timeout!!\n");
-			return -1;
+			return -ETIMEDOUT;
 		}
 	}
 
@@ -292,26 +293,27 @@ static int au1000_mdio_read(struct net_device *dev, int phy_addr, int reg)
 		mdelay(1);
 		if (--timedout == 0) {
 			netdev_err(dev, "mdio_read busy timeout!!\n");
-			return -1;
+			return -ETIMEDOUT;
 		}
 	}
 	return readl(mii_data_reg);
 }
 
-static void au1000_mdio_write(struct net_device *dev, int phy_addr,
-			      int reg, u16 value)
+static int au1000_mdio_write(struct net_device *dev, int phy_addr,
+			     int reg, u16 value)
 {
 	struct au1000_private *aup = netdev_priv(dev);
 	u32 *const mii_control_reg = &aup->mac->mii_control;
 	u32 *const mii_data_reg = &aup->mac->mii_data;
 	u32 timedout = 20;
 	u32 mii_control;
+	int ret;
 
 	while (readl(mii_control_reg) & MAC_MII_BUSY) {
 		mdelay(1);
 		if (--timedout == 0) {
 			netdev_err(dev, "mdio_write busy timeout!!\n");
-			return;
+			return -ETIMEDOUT;
 		}
 	}
 
@@ -320,6 +322,13 @@ static void au1000_mdio_write(struct net_device *dev, int phy_addr,
 
 	writel(value, mii_data_reg);
 	writel(mii_control, mii_control_reg);
+
+	ret = readl_poll_timeout(mii_control_reg, mii_control,
+				 !(mii_control & MAC_MII_BUSY), 20, 20000);
+	if (ret)
+		netdev_err(dev, "mdio_write busy timeout!!\n");
+
+	return ret;
 }
 
 static int au1000_mdiobus_read(struct mii_bus *bus, int phy_addr, int regnum)
@@ -344,8 +353,7 @@ static int au1000_mdiobus_write(struct mii_bus *bus, int phy_addr, int regnum,
 	 */
 	au1000_enable_mac(dev, 0);
 
-	au1000_mdio_write(dev, phy_addr, regnum, value);
-	return 0;
+	return au1000_mdio_write(dev, phy_addr, regnum, value);
 }
 
 static int au1000_mdiobus_reset(struct mii_bus *bus)
-- 
2.53.0