diff options
| -rw-r--r-- | drivers/net/ethernet/arc/emac_main.c | 53 |
1 files changed, 37 insertions, 16 deletions
diff --git a/drivers/net/ethernet/arc/emac_main.c b/drivers/net/ethernet/arc/emac_main.c index fe5cfeace6e3..5919394d9f58 100644 --- a/drivers/net/ethernet/arc/emac_main.c +++ b/drivers/net/ethernet/arc/emac_main.c @@ -30,6 +30,17 @@ #define DRV_VERSION "1.0" /** + * arc_emac_tx_avail - Return the number of available slots in the tx ring. + * @priv: Pointer to ARC EMAC private data structure. + * + * returns: the number of slots available for transmission in tx the ring. + */ +static inline int arc_emac_tx_avail(struct arc_emac_priv *priv) +{ + return (priv->txbd_dirty + TX_BD_NUM - priv->txbd_curr - 1) % TX_BD_NUM; +} + +/** * arc_emac_adjust_link - Adjust the PHY link duplex. * @ndev: Pointer to the net_device structure. * @@ -180,10 +191,15 @@ static void arc_emac_tx_clean(struct net_device *ndev) txbd->info = 0; *txbd_dirty = (*txbd_dirty + 1) % TX_BD_NUM; - - if (netif_queue_stopped(ndev)) - netif_wake_queue(ndev); } + + /* Ensure that txbd_dirty is visible to tx() before checking + * for queue stopped. + */ + smp_mb(); + + if (netif_queue_stopped(ndev) && arc_emac_tx_avail(priv)) + netif_wake_queue(ndev); } /** @@ -298,7 +314,7 @@ static int arc_emac_poll(struct napi_struct *napi, int budget) work_done = arc_emac_rx(ndev, budget); if (work_done < budget) { napi_complete(napi); - arc_reg_or(priv, R_ENABLE, RXINT_MASK); + arc_reg_or(priv, R_ENABLE, RXINT_MASK | TXINT_MASK); } return work_done; @@ -327,9 +343,9 @@ static irqreturn_t arc_emac_intr(int irq, void *dev_instance) /* Reset all flags except "MDIO complete" */ arc_reg_set(priv, R_STATUS, status); - if (status & RXINT_MASK) { + if (status & (RXINT_MASK | TXINT_MASK)) { if (likely(napi_schedule_prep(&priv->napi))) { - arc_reg_clr(priv, R_ENABLE, RXINT_MASK); + arc_reg_clr(priv, R_ENABLE, RXINT_MASK | TXINT_MASK); __napi_schedule(&priv->napi); } } @@ -440,7 +456,7 @@ static int arc_emac_open(struct net_device *ndev) arc_reg_set(priv, R_TX_RING, (unsigned int)priv->txbd_dma); /* Enable interrupts */ - arc_reg_set(priv, R_ENABLE, RXINT_MASK | ERR_MASK); + arc_reg_set(priv, R_ENABLE, RXINT_MASK | TXINT_MASK | ERR_MASK); /* Set CONTROL */ arc_reg_set(priv, R_CTRL, @@ -511,7 +527,7 @@ static int arc_emac_stop(struct net_device *ndev) netif_stop_queue(ndev); /* Disable interrupts */ - arc_reg_clr(priv, R_ENABLE, RXINT_MASK | ERR_MASK); + arc_reg_clr(priv, R_ENABLE, RXINT_MASK | TXINT_MASK | ERR_MASK); /* Disable EMAC */ arc_reg_clr(priv, R_CTRL, EN_MASK); @@ -574,11 +590,9 @@ static int arc_emac_tx(struct sk_buff *skb, struct net_device *ndev) len = max_t(unsigned int, ETH_ZLEN, skb->len); - /* EMAC still holds this buffer in its possession. - * CPU must not modify this buffer descriptor - */ - if (unlikely((le32_to_cpu(*info) & OWN_MASK) == FOR_EMAC)) { + if (unlikely(!arc_emac_tx_avail(priv))) { netif_stop_queue(ndev); + netdev_err(ndev, "BUG! Tx Ring full when queue awake!\n"); return NETDEV_TX_BUSY; } @@ -607,12 +621,19 @@ static int arc_emac_tx(struct sk_buff *skb, struct net_device *ndev) /* Increment index to point to the next BD */ *txbd_curr = (*txbd_curr + 1) % TX_BD_NUM; - /* Get "info" of the next BD */ - info = &priv->txbd[*txbd_curr].info; + /* Ensure that tx_clean() sees the new txbd_curr before + * checking the queue status. This prevents an unneeded wake + * of the queue in tx_clean(). + */ + smp_mb(); - /* Check if if Tx BD ring is full - next BD is still owned by EMAC */ - if (unlikely((le32_to_cpu(*info) & OWN_MASK) == FOR_EMAC)) + if (!arc_emac_tx_avail(priv)) { netif_stop_queue(ndev); + /* Refresh tx_dirty */ + smp_mb(); + if (arc_emac_tx_avail(priv)) + netif_start_queue(ndev); + } arc_reg_set(priv, R_STATUS, TXPL_MASK); |