Staging: Octeon: Run phy bus accesses on a workqueue.

When directly accessing a phy, we must acquire the mdio bus lock.  To
do that we cannot be in interrupt context, so we need to move these
operations to a workqueue.

Signed-off-by: David Daney <ddaney@caviumnetworks.com>
To: linux-mips@linux-mips.org
To: netdev@vger.kernel.org
To: gregkh@suse.de
Patchwork: http://patchwork.linux-mips.org/patch/965/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

3 files changed, 109 insertions, 63 deletions

diff --git a/drivers/staging/octeon/ethernet-rgmii.c b/drivers/staging/octeon/ethernet-rgmii.c
index f90d46ed5640..a0d4d4b98bdc 100644
--- a/drivers/staging/octeon/ethernet-rgmii.c
+++ b/drivers/staging/octeon/ethernet-rgmii.c
@@ -26,6 +26,7 @@
 **********************************************************************/
 #include <linux/kernel.h>
 #include <linux/netdevice.h>
+#include <linux/phy.h>
 #include <net/dst.h>
 
 #include <asm/octeon/octeon.h>
@@ -47,14 +48,20 @@ static int number_rgmii_ports;
 static void cvm_oct_rgmii_poll(struct net_device *dev)
 {
         struct octeon_ethernet *priv = netdev_priv(dev);
-        unsigned long flags;
+        unsigned long flags = 0;
         cvmx_helper_link_info_t link_info;
+        int use_global_register_lock = (priv->phydev == NULL);
 
-        /*
-         * Take the global register lock since we are going to touch
-         * registers that affect more than one port.
-         */
-        spin_lock_irqsave(&global_register_lock, flags);
+        BUG_ON(in_interrupt());
+        if (use_global_register_lock) {
+                /*
+                 * Take the global register lock since we are going to
+                 * touch registers that affect more than one port.
+                 */
+                spin_lock_irqsave(&global_register_lock, flags);
+        } else {
+                mutex_lock(&priv->phydev->bus->mdio_lock);
+        }
 
         link_info = cvmx_helper_link_get(priv->port);
         if (link_info.u64 == priv->link_info) {
@@ -114,7 +121,11 @@ static void cvm_oct_rgmii_poll(struct net_device *dev)
                                      dev->name);
                         }
                 }
-                spin_unlock_irqrestore(&global_register_lock, flags);
+
+                if (use_global_register_lock)
+                        spin_unlock_irqrestore(&global_register_lock, flags);
+                else
+                        mutex_unlock(&priv->phydev->bus->mdio_lock);
                 return;
         }
 
@@ -150,7 +161,12 @@ static void cvm_oct_rgmii_poll(struct net_device *dev)
                 link_info = cvmx_helper_link_autoconf(priv->port);
                 priv->link_info = link_info.u64;
         }
-        spin_unlock_irqrestore(&global_register_lock, flags);
+
+        if (use_global_register_lock)
+                spin_unlock_irqrestore(&global_register_lock, flags);
+        else {
+                mutex_unlock(&priv->phydev->bus->mdio_lock);
+        }
 
         if (priv->phydev == NULL) {
                 /* Tell core. */
@@ -212,8 +228,11 @@ static irqreturn_t cvm_oct_rgmii_rml_interrupt(int cpl, void *dev_id)
                                 struct net_device *dev =
                                     cvm_oct_device[cvmx_helper_get_ipd_port
                                                    (interface, index)];
-                                if (dev)
-                                        cvm_oct_rgmii_poll(dev);
+                                struct octeon_ethernet *priv = netdev_priv(dev);
+
+                                if (dev && !atomic_read(&cvm_oct_poll_queue_stopping))
+                                        queue_work(cvm_oct_poll_queue, &priv->port_work);
+
                                 gmx_rx_int_reg.u64 = 0;
                                 gmx_rx_int_reg.s.phy_dupx = 1;
                                 gmx_rx_int_reg.s.phy_link = 1;
@@ -251,8 +270,11 @@ static irqreturn_t cvm_oct_rgmii_rml_interrupt(int cpl, void *dev_id)
                                 struct net_device *dev =
                                     cvm_oct_device[cvmx_helper_get_ipd_port
                                                    (interface, index)];
-                                if (dev)
-                                        cvm_oct_rgmii_poll(dev);
+                                struct octeon_ethernet *priv = netdev_priv(dev);
+
+                                if (dev && !atomic_read(&cvm_oct_poll_queue_stopping))
+                                        queue_work(cvm_oct_poll_queue, &priv->port_work);
+
                                 gmx_rx_int_reg.u64 = 0;
                                 gmx_rx_int_reg.s.phy_dupx = 1;
                                 gmx_rx_int_reg.s.phy_link = 1;
@@ -301,6 +323,12 @@ int cvm_oct_rgmii_stop(struct net_device *dev)
         return 0;
 }
 
+static void cvm_oct_rgmii_immediate_poll(struct work_struct *work)
+{
+        struct octeon_ethernet *priv = container_of(work, struct octeon_ethernet, port_work);
+        cvm_oct_rgmii_poll(cvm_oct_device[priv->port]);
+}
+
 int cvm_oct_rgmii_init(struct net_device *dev)
 {
         struct octeon_ethernet *priv = netdev_priv(dev);
@@ -308,7 +336,7 @@ int cvm_oct_rgmii_init(struct net_device *dev)
 
         cvm_oct_common_init(dev);
         dev->netdev_ops->ndo_stop(dev);
-
+        INIT_WORK(&priv->port_work, cvm_oct_rgmii_immediate_poll);
         /*
          * Due to GMX errata in CN3XXX series chips, it is necessary
          * to take the link down immediately when the PHY changes
@@ -396,4 +424,5 @@ void cvm_oct_rgmii_uninit(struct net_device *dev)
         number_rgmii_ports--;
         if (number_rgmii_ports == 0)
                 free_irq(OCTEON_IRQ_RML, &number_rgmii_ports);
+        cancel_work_sync(&priv->port_work);
 }
diff --git a/drivers/staging/octeon/ethernet.c b/drivers/staging/octeon/ethernet.c
index 5afece0216ca..1771c1035a3c 100644
--- a/drivers/staging/octeon/ethernet.c
+++ b/drivers/staging/octeon/ethernet.c
@@ -123,9 +123,16 @@ MODULE_PARM_DESC(rx_napi_weight, "The NAPI WEIGHT parameter.");
 static unsigned int cvm_oct_mac_addr_offset;
 
 /**
- * Periodic timer to check auto negotiation
+ * cvm_oct_poll_queue - Workqueue for polling operations.
  */
-static struct timer_list cvm_oct_poll_timer;
+struct workqueue_struct *cvm_oct_poll_queue;
+
+/**
+ * cvm_oct_poll_queue_stopping - flag to indicate polling should stop.
+ *
+ * Set to one right before cvm_oct_poll_queue is destroyed.
+ */
+atomic_t cvm_oct_poll_queue_stopping = ATOMIC_INIT(0);
 
 /**
  * Array of every ethernet device owned by this driver indexed by
@@ -133,47 +140,39 @@ static struct timer_list cvm_oct_poll_timer;
  */
 struct net_device *cvm_oct_device[TOTAL_NUMBER_OF_PORTS];
 
-/**
- * Periodic timer tick for slow management operations
- *
- * @arg:    Device to check
- */
-static void cvm_do_timer(unsigned long arg)
+static void cvm_oct_rx_refill_worker(struct work_struct *work);
+static DECLARE_DELAYED_WORK(cvm_oct_rx_refill_work, cvm_oct_rx_refill_worker);
+
+static void cvm_oct_rx_refill_worker(struct work_struct *work)
 {
-        static int port;
-        if (port < CVMX_PIP_NUM_INPUT_PORTS) {
-                if (cvm_oct_device[port]) {
-                        struct octeon_ethernet *priv = netdev_priv(cvm_oct_device[port]);
-                        if (priv->poll)
-                                priv->poll(cvm_oct_device[port]);
-                        cvm_oct_free_tx_skbs(priv);
-                        cvm_oct_device[port]->netdev_ops->ndo_get_stats(cvm_oct_device[port]);
-                }
-                port++;
-                /*
-                 * Poll the next port in a 50th of a second.  This
-                 * spreads the polling of ports out a little bit.
-                 */
-                mod_timer(&cvm_oct_poll_timer, jiffies + HZ/50);
-        } else {
-                port = 0;
-                /*
-                 * FPA 0 may have been drained, try to refill it if we
-                 * need more than num_packet_buffers / 2, otherwise
-                 * normal receive processing will refill it.  If it
-                 * were drained, no packets could be received so
-                 * cvm_oct_napi_poll would never be invoked to do the
-                 * refill.
-                 */
-                cvm_oct_rx_refill_pool(num_packet_buffers / 2);
-                /*
-                 * All ports have been polled. Start the next iteration through
-                 * the ports in one second.
-                 */
-                mod_timer(&cvm_oct_poll_timer, jiffies + HZ);
-        }
+        /*
+         * FPA 0 may have been drained, try to refill it if we need
+         * more than num_packet_buffers / 2, otherwise normal receive
+         * processing will refill it.  If it were drained, no packets
+         * could be received so cvm_oct_napi_poll would never be
+         * invoked to do the refill.
+         */
+        cvm_oct_rx_refill_pool(num_packet_buffers / 2);
+
+        if (!atomic_read(&cvm_oct_poll_queue_stopping))
+                queue_delayed_work(cvm_oct_poll_queue,
+                                   &cvm_oct_rx_refill_work, HZ);
 }
 
+static void cvm_oct_tx_clean_worker(struct work_struct *work)
+{
+        struct octeon_ethernet *priv = container_of(work,
+                                                    struct octeon_ethernet,
+                                                    tx_clean_work.work);
+
+        if (priv->poll)
+                priv->poll(cvm_oct_device[priv->port]);
+        cvm_oct_free_tx_skbs(priv);
+        cvm_oct_device[priv->port]->netdev_ops->ndo_get_stats(cvm_oct_device[priv->port]);
+        if (!atomic_read(&cvm_oct_poll_queue_stopping))
+                queue_delayed_work(cvm_oct_poll_queue, &priv->tx_clean_work, HZ);
+ }
+
 /**
  * Configure common hardware for all interfaces
  */
@@ -624,6 +623,12 @@ static int __init cvm_oct_init_module(void)
         else
                 cvm_oct_mac_addr_offset = 0;
 
+        cvm_oct_poll_queue = create_singlethread_workqueue("octeon-ethernet");
+        if (cvm_oct_poll_queue == NULL) {
+                pr_err("octeon-ethernet: Cannot create workqueue");
+                return -ENOMEM;
+        }
+
         cvm_oct_proc_initialize();
         cvm_oct_configure_common_hw();
 
@@ -719,7 +724,9 @@ static int __init cvm_oct_init_module(void)
 
                         /* Initialize the device private structure. */
                         priv = netdev_priv(dev);
-                        memset(priv, 0, sizeof(struct octeon_ethernet));
+
+                        INIT_DELAYED_WORK(&priv->tx_clean_work,
+                                          cvm_oct_tx_clean_worker);
 
                         priv->imode = imode;
                         priv->port = port;
@@ -785,17 +792,15 @@ static int __init cvm_oct_init_module(void)
                                 fau -=
                                     cvmx_pko_get_num_queues(priv->port) *
                                     sizeof(uint32_t);
+                                queue_delayed_work(cvm_oct_poll_queue,
+                                                   &priv->tx_clean_work, HZ);
                         }
                 }
         }
 
         cvm_oct_rx_initialize();
 
-        /* Enable the poll timer for checking RGMII status */
-        init_timer(&cvm_oct_poll_timer);
-        cvm_oct_poll_timer.data = 0;
-        cvm_oct_poll_timer.function = cvm_do_timer;
-        mod_timer(&cvm_oct_poll_timer, jiffies + HZ);
+        queue_delayed_work(cvm_oct_poll_queue, &cvm_oct_rx_refill_work, HZ);
 
         return 0;
 }
@@ -817,20 +822,28 @@ static void __exit cvm_oct_cleanup_module(void)
         /* Free the interrupt handler */
         free_irq(OCTEON_IRQ_WORKQ0 + pow_receive_group, cvm_oct_device);
 
-        del_timer(&cvm_oct_poll_timer);
+        atomic_inc_return(&cvm_oct_poll_queue_stopping);
+        cancel_delayed_work_sync(&cvm_oct_rx_refill_work);
+
         cvm_oct_rx_shutdown();
         cvmx_pko_disable();
 
         /* Free the ethernet devices */
         for (port = 0; port < TOTAL_NUMBER_OF_PORTS; port++) {
                 if (cvm_oct_device[port]) {
-                        cvm_oct_tx_shutdown(cvm_oct_device[port]);
-                        unregister_netdev(cvm_oct_device[port]);
-                        kfree(cvm_oct_device[port]);
+                        struct net_device *dev = cvm_oct_device[port];
+                        struct octeon_ethernet *priv = netdev_priv(dev);
+                        cancel_delayed_work_sync(&priv->tx_clean_work);
+
+                        cvm_oct_tx_shutdown(dev);
+                        unregister_netdev(dev);
+                        kfree(dev);
                         cvm_oct_device[port] = NULL;
                 }
         }
 
+        destroy_workqueue(cvm_oct_poll_queue);
+
         cvmx_pko_shutdown();
         cvm_oct_proc_shutdown();
 
diff --git a/drivers/staging/octeon/octeon-ethernet.h b/drivers/staging/octeon/octeon-ethernet.h
index 40b695615431..8d0921061dac 100644
--- a/drivers/staging/octeon/octeon-ethernet.h
+++ b/drivers/staging/octeon/octeon-ethernet.h
@@ -61,6 +61,8 @@ struct octeon_ethernet {
         void (*poll) (struct net_device *dev);
         struct hrtimer          tx_restart_timer;
         ktime_t                 tx_restart_interval;
+        struct delayed_work     tx_clean_work;
+        struct work_struct      port_work;      /* may be unused. */
 };
 
 /**
@@ -97,6 +99,8 @@ extern int pow_send_group;
 extern int pow_receive_group;
 extern char pow_send_list[];
 extern struct net_device *cvm_oct_device[];
+extern struct workqueue_struct *cvm_oct_poll_queue;
+extern atomic_t cvm_oct_poll_queue_stopping;
 
 extern int max_rx_cpus;
 extern int rx_napi_weight;