ftgmac100: Add a reset task and use it for link changes

Link speed changes require a full HW reset. This isn't done
properly at the moment. It will involve delays and thus isn't
suitable to do from the link poll callback.

So let's create a reset_task that we can queue up when the
link changes. It will be useful for various cases of error
handling as well.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/ethernet/faraday/ftgmac100.c b/drivers/net/ethernet/faraday/ftgmac100.c
index 7f46d9c18f11266045f8009dc67a86c08bf5edc8..88c492e956da42dede32cada0bfbaa1f7939a115 100644 (file)
--- a/drivers/net/ethernet/faraday/ftgmac100.c
+++ b/drivers/net/ethernet/faraday/ftgmac100.c
@@ -76,6 +76,7 @@ struct ftgmac100 {
        struct device *dev;
        struct ncsi_dev *ndev;
        struct napi_struct napi;
+       struct work_struct reset_task;
        struct mii_bus *mii_bus;
 
        /* Link management */
@@ -874,7 +875,6 @@ static void ftgmac100_adjust_link(struct net_device *netdev)
        struct ftgmac100 *priv = netdev_priv(netdev);
        struct phy_device *phydev = netdev->phydev;
        int new_speed;
-       int ier;
 
        /* We store "no link" as speed 0 */
        if (!phydev->link)
@@ -899,20 +899,11 @@ static void ftgmac100_adjust_link(struct net_device *netdev)
        if (!new_speed)
                return;
 
-       ier = ioread32(priv->base + FTGMAC100_OFFSET_IER);
-
-       /* disable all interrupts */
+       /* Disable all interrupts */
        iowrite32(0, priv->base + FTGMAC100_OFFSET_IER);
 
-       netif_stop_queue(netdev);
-       ftgmac100_stop_hw(priv);
-
-       netif_start_queue(netdev);
-       ftgmac100_init_hw(priv);
-       ftgmac100_start_hw(priv);
-
-       /* re-enable interrupts */
-       iowrite32(ier, priv->base + FTGMAC100_OFFSET_IER);
+       /* Reset the adapter asynchronously */
+       schedule_work(&priv->reset_task);
 }
 
 static int ftgmac100_mii_probe(struct ftgmac100 *priv)
@@ -1137,6 +1128,61 @@ static int ftgmac100_init_all(struct ftgmac100 *priv, bool ignore_alloc_err)
        return err;
 }
 
+static void ftgmac100_reset_task(struct work_struct *work)
+{
+       struct ftgmac100 *priv = container_of(work, struct ftgmac100,
+                                             reset_task);
+       struct net_device *netdev = priv->netdev;
+       int err;
+
+       netdev_dbg(netdev, "Resetting NIC...\n");
+
+       /* Lock the world */
+       rtnl_lock();
+       if (netdev->phydev)
+               mutex_lock(&netdev->phydev->lock);
+       if (priv->mii_bus)
+               mutex_lock(&priv->mii_bus->mdio_lock);
+
+
+       /* Check if the interface is still up */
+       if (!netif_running(netdev))
+               goto bail;
+
+       /* Stop the network stack */
+       netif_trans_update(netdev);
+       napi_disable(&priv->napi);
+       netif_tx_disable(netdev);
+
+       /* Stop and reset the MAC */
+       ftgmac100_stop_hw(priv);
+       err = ftgmac100_reset_hw(priv);
+       if (err) {
+               /* Not much we can do ... it might come back... */
+               netdev_err(netdev, "attempting to continue...\n");
+       }
+
+       /* Free all rx and tx buffers */
+       ftgmac100_free_buffers(priv);
+
+       /* The ring pointers have been reset in HW, reflect this here */
+       priv->rx_pointer = 0;
+       priv->tx_clean_pointer = 0;
+       priv->tx_pointer = 0;
+       priv->tx_pending = 0;
+
+       /* Setup everything again and restart chip */
+       ftgmac100_init_all(priv, true);
+
+       netdev_dbg(netdev, "Reset done !\n");
+ bail:
+       if (priv->mii_bus)
+               mutex_unlock(&priv->mii_bus->mdio_lock);
+       if (netdev->phydev)
+               mutex_unlock(&netdev->phydev->lock);
+       rtnl_unlock();
+}
+
 static int ftgmac100_open(struct net_device *netdev)
 {
        struct ftgmac100 *priv = netdev_priv(netdev);
@@ -1222,6 +1268,14 @@ static int ftgmac100_stop(struct net_device *netdev)
 {
        struct ftgmac100 *priv = netdev_priv(netdev);
 
+       /* Note about the reset task: We are called with the rtnl lock
+        * held, so we are synchronized against the core of the reset
+        * task. We must not try to synchronously cancel it otherwise
+        * we can deadlock. But since it will test for netif_running()
+        * which has already been cleared by the net core, we don't
+        * anything special to do.
+        */
+
        /* disable all interrupts */
        iowrite32(0, priv->base + FTGMAC100_OFFSET_IER);
 
@@ -1397,6 +1451,7 @@ static int ftgmac100_probe(struct platform_device *pdev)
        priv = netdev_priv(netdev);
        priv->netdev = netdev;
        priv->dev = &pdev->dev;
+       INIT_WORK(&priv->reset_task, ftgmac100_reset_task);
 
        spin_lock_init(&priv->tx_lock);
 
@@ -1500,6 +1555,12 @@ static int ftgmac100_remove(struct platform_device *pdev)
        priv = netdev_priv(netdev);
 
        unregister_netdev(netdev);
+
+       /* There's a small chance the reset task will have been re-queued,
+        * during stop, make sure it's gone before we free the structure.
+        */
+       cancel_work_sync(&priv->reset_task);
+
        ftgmac100_destroy_mdio(netdev);
 
        iounmap(priv->base);