fjes: tx_stall_task

This patch adds tx_stall_task.
When receiver's buffer is full, sender stops
its tx queue. This task is used to monitor
receiver's status and when receiver's buffer
is avairable, it resumes tx queue.

Signed-off-by: Taku Izumi <izumi.taku@jp.fujitsu.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/fjes/fjes.h b/drivers/net/fjes/fjes.h
index 8e9899e..b04ea9d 100644 (file)
--- a/drivers/net/fjes/fjes.h
+++ b/drivers/net/fjes/fjes.h
@@ -30,6 +30,7 @@
 #define FJES_MAX_QUEUES                1
 #define FJES_TX_RETRY_INTERVAL (20 * HZ)
 #define FJES_TX_RETRY_TIMEOUT  (100)
+#define FJES_TX_TX_STALL_TIMEOUT       (FJES_TX_RETRY_INTERVAL / 2)
 #define FJES_OPEN_ZONE_UPDATE_WAIT     (300) /* msec */
 
 /* board specific private data structure */
@@ -52,6 +53,7 @@ struct fjes_adapter {
 
        struct workqueue_struct *txrx_wq;
 
+       struct work_struct tx_stall_task;
        struct work_struct raise_intr_rxdata_task;
 
        struct fjes_hw hw;

diff --git a/drivers/net/fjes/fjes_main.c b/drivers/net/fjes/fjes_main.c
index 80e180f..ac1e076 100644 (file)
--- a/drivers/net/fjes/fjes_main.c
+++ b/drivers/net/fjes/fjes_main.c
@@ -53,6 +53,7 @@ static int fjes_setup_resources(struct fjes_adapter *);
 static void fjes_free_resources(struct fjes_adapter *);
 static netdev_tx_t fjes_xmit_frame(struct sk_buff *, struct net_device *);
 static void fjes_raise_intr_rxdata_task(struct work_struct *);
+static void fjes_tx_stall_task(struct work_struct *);
 static irqreturn_t fjes_intr(int, void*);
 
 static int fjes_acpi_add(struct acpi_device *);
@@ -278,6 +279,7 @@ static int fjes_close(struct net_device *netdev)
        fjes_free_irq(adapter);
 
        cancel_work_sync(&adapter->raise_intr_rxdata_task);
+       cancel_work_sync(&adapter->tx_stall_task);
 
        fjes_hw_wait_epstop(hw);
 
@@ -407,6 +409,59 @@ static void fjes_free_resources(struct fjes_adapter *adapter)
        }
 }
 
+static void fjes_tx_stall_task(struct work_struct *work)
+{
+       struct fjes_adapter *adapter = container_of(work,
+                       struct fjes_adapter, tx_stall_task);
+       struct net_device *netdev = adapter->netdev;
+       struct fjes_hw *hw = &adapter->hw;
+       int all_queue_available, sendable;
+       enum ep_partner_status pstatus;
+       int max_epid, my_epid, epid;
+       union ep_buffer_info *info;
+       int i;
+
+       if (((long)jiffies -
+               (long)(netdev->trans_start)) > FJES_TX_TX_STALL_TIMEOUT) {
+               netif_wake_queue(netdev);
+               return;
+       }
+
+       my_epid = hw->my_epid;
+       max_epid = hw->max_epid;
+
+       for (i = 0; i < 5; i++) {
+               all_queue_available = 1;
+
+               for (epid = 0; epid < max_epid; epid++) {
+                       if (my_epid == epid)
+                               continue;
+
+                       pstatus = fjes_hw_get_partner_ep_status(hw, epid);
+                       sendable = (pstatus == EP_PARTNER_SHARED);
+                       if (!sendable)
+                               continue;
+
+                       info = adapter->hw.ep_shm_info[epid].tx.info;
+
+                       if (EP_RING_FULL(info->v1i.head, info->v1i.tail,
+                                        info->v1i.count_max)) {
+                               all_queue_available = 0;
+                               break;
+                       }
+               }
+
+               if (all_queue_available) {
+                       netif_wake_queue(netdev);
+                       return;
+               }
+       }
+
+       usleep_range(50, 100);
+
+       queue_work(adapter->txrx_wq, &adapter->tx_stall_task);
+}
+
 static void fjes_raise_intr_rxdata_task(struct work_struct *work)
 {
        struct fjes_adapter *adapter = container_of(work,
@@ -602,6 +657,10 @@ fjes_xmit_frame(struct sk_buff *skb, struct net_device *netdev)
                                        netdev->trans_start = jiffies;
                                        netif_tx_stop_queue(cur_queue);
 
+                                       if (!work_pending(&adapter->tx_stall_task))
+                                               queue_work(adapter->txrx_wq,
+                                                          &adapter->tx_stall_task);
+
                                        ret = NETDEV_TX_BUSY;
                                }
                        } else {
@@ -686,6 +745,7 @@ static int fjes_probe(struct platform_device *plat_dev)
 
        adapter->txrx_wq = create_workqueue(DRV_NAME "/txrx");
 
+       INIT_WORK(&adapter->tx_stall_task, fjes_tx_stall_task);
        INIT_WORK(&adapter->raise_intr_rxdata_task,
                  fjes_raise_intr_rxdata_task);
 
@@ -729,6 +789,7 @@ static int fjes_remove(struct platform_device *plat_dev)
        struct fjes_hw *hw = &adapter->hw;
 
        cancel_work_sync(&adapter->raise_intr_rxdata_task);
+       cancel_work_sync(&adapter->tx_stall_task);
        if (adapter->txrx_wq)
                destroy_workqueue(adapter->txrx_wq);