From 83617317d2136ca18265955de7782c33be27ff62 Mon Sep 17 00:00:00 2001 From: Benjamin Herrenschmidt Date: Mon, 10 Apr 2017 11:15:20 +1000 Subject: [PATCH] ftgmac100: Store tx skbs in a separate array Rather than in the descriptor. The descriptor is mapped non-cachable and rather slow to access. Since to do that we need to keep track of the tx "pointer" we also have no use of all the accesors to manipulate it, just open code it, it's as clear and will help when adding fragmented sends. Signed-off-by: Benjamin Herrenschmidt Signed-off-by: David S. Miller --- drivers/net/ethernet/faraday/ftgmac100.c | 59 +++++++++----------------------- 1 file changed, 16 insertions(+), 43 deletions(-) diff --git a/drivers/net/ethernet/faraday/ftgmac100.c b/drivers/net/ethernet/faraday/ftgmac100.c index 6325e32..b4d84e7 100644 --- a/drivers/net/ethernet/faraday/ftgmac100.c +++ b/drivers/net/ethernet/faraday/ftgmac100.c @@ -65,6 +65,7 @@ struct ftgmac100 { u32 rxdes0_edorr_mask; /* Tx ring */ + struct sk_buff *tx_skbs[TX_QUEUE_ENTRIES]; unsigned int tx_clean_pointer; unsigned int tx_pointer; unsigned int tx_pending; @@ -545,63 +546,29 @@ static dma_addr_t ftgmac100_txdes_get_dma_addr(struct ftgmac100_txdes *txdes) return le32_to_cpu(txdes->txdes3); } -/* - * txdes2 is not used by hardware. We use it to keep track of socket buffer. - * Since hardware does not touch it, we can skip cpu_to_le32()/le32_to_cpu(). - */ -static void ftgmac100_txdes_set_skb(struct ftgmac100_txdes *txdes, - struct sk_buff *skb) -{ - txdes->txdes2 = (unsigned int)skb; -} - -static struct sk_buff *ftgmac100_txdes_get_skb(struct ftgmac100_txdes *txdes) -{ - return (struct sk_buff *)txdes->txdes2; -} - static int ftgmac100_next_tx_pointer(int pointer) { return (pointer + 1) & (TX_QUEUE_ENTRIES - 1); } -static void ftgmac100_tx_pointer_advance(struct ftgmac100 *priv) -{ - priv->tx_pointer = ftgmac100_next_tx_pointer(priv->tx_pointer); -} - -static void ftgmac100_tx_clean_pointer_advance(struct ftgmac100 *priv) -{ - priv->tx_clean_pointer = ftgmac100_next_tx_pointer(priv->tx_clean_pointer); -} - -static struct ftgmac100_txdes *ftgmac100_current_txdes(struct ftgmac100 *priv) -{ - return &priv->descs->txdes[priv->tx_pointer]; -} - -static struct ftgmac100_txdes * -ftgmac100_current_clean_txdes(struct ftgmac100 *priv) -{ - return &priv->descs->txdes[priv->tx_clean_pointer]; -} - static bool ftgmac100_tx_complete_packet(struct ftgmac100 *priv) { struct net_device *netdev = priv->netdev; struct ftgmac100_txdes *txdes; + unsigned int pointer; struct sk_buff *skb; dma_addr_t map; if (priv->tx_pending == 0) return false; - txdes = ftgmac100_current_clean_txdes(priv); + pointer = priv->tx_clean_pointer; + txdes = &priv->descs->txdes[pointer]; if (ftgmac100_txdes_owned_by_dma(txdes)) return false; - skb = ftgmac100_txdes_get_skb(txdes); + skb = priv->tx_skbs[pointer]; map = ftgmac100_txdes_get_dma_addr(txdes); netdev->stats.tx_packets++; @@ -610,10 +577,11 @@ static bool ftgmac100_tx_complete_packet(struct ftgmac100 *priv) dma_unmap_single(priv->dev, map, skb_headlen(skb), DMA_TO_DEVICE); dev_kfree_skb(skb); + priv->tx_skbs[pointer] = NULL; ftgmac100_txdes_reset(priv, txdes); - ftgmac100_tx_clean_pointer_advance(priv); + priv->tx_clean_pointer = ftgmac100_next_tx_pointer(pointer); spin_lock(&priv->tx_lock); priv->tx_pending--; @@ -634,6 +602,7 @@ static int ftgmac100_hard_start_xmit(struct sk_buff *skb, { struct ftgmac100 *priv = netdev_priv(netdev); struct ftgmac100_txdes *txdes; + unsigned int pointer; dma_addr_t map; /* The HW doesn't pad small frames */ @@ -657,11 +626,12 @@ static int ftgmac100_hard_start_xmit(struct sk_buff *skb, goto drop; } - txdes = ftgmac100_current_txdes(priv); - ftgmac100_tx_pointer_advance(priv); + /* Grab the next free tx descriptor */ + pointer = priv->tx_pointer; + txdes = &priv->descs->txdes[pointer]; /* setup TX descriptor */ - ftgmac100_txdes_set_skb(txdes, skb); + priv->tx_skbs[pointer] = skb; ftgmac100_txdes_set_dma_addr(txdes, map); ftgmac100_txdes_set_buffer_size(txdes, skb->len); @@ -682,6 +652,9 @@ static int ftgmac100_hard_start_xmit(struct sk_buff *skb, } } + /* Update next TX pointer */ + priv->tx_pointer = ftgmac100_next_tx_pointer(pointer); + spin_lock(&priv->tx_lock); priv->tx_pending++; if (priv->tx_pending == TX_QUEUE_ENTRIES) @@ -724,7 +697,7 @@ static void ftgmac100_free_buffers(struct ftgmac100 *priv) /* Free all TX buffers */ for (i = 0; i < TX_QUEUE_ENTRIES; i++) { struct ftgmac100_txdes *txdes = &priv->descs->txdes[i]; - struct sk_buff *skb = ftgmac100_txdes_get_skb(txdes); + struct sk_buff *skb = priv->tx_skbs[i]; dma_addr_t map = ftgmac100_txdes_get_dma_addr(txdes); if (!skb) -- 2.7.4