From 66d06757d9eb74a29775737b8c770e3b57e536d9 Mon Sep 17 00:00:00 2001 From: Petri Gynther Date: Wed, 4 Mar 2015 14:30:01 -0800 Subject: [PATCH] net: bcmgenet: simplify __bcmgenet_tx_reclaim() 1. Use c_index and ring->c_index to determine how many TxCBs/TxBDs are ready for cleanup - c_index = the current value of TDMA_CONS_INDEX - TDMA_CONS_INDEX is HW-incremented and auto-wraparound (0x0-0xFFFF) - ring->c_index = __bcmgenet_tx_reclaim() cleaned up to this point on the previous invocation 2. Add bcmgenet_tx_ring->clean_ptr - index of the next TxCB to be cleaned - incremented as TxCBs/TxBDs are processed - value always in range [ring->cb_ptr, ring->end_ptr] 3. Fix incrementing of dev->stats.tx_packets - should be incremented only when tx_cb_ptr->skb != NULL These changes simplify __bcmgenet_tx_reclaim(). Furthermore, Tx ring size can now be any value. With the old code, Tx ring size had to be a power-of-2: num_tx_bds = ring->size; c_index &= (num_tx_bds - 1); last_c_index &= (num_tx_bds - 1); Signed-off-by: Petri Gynther Reviewed-by: Florian Fainelli Signed-off-by: David S. Miller --- .../net/ethernet/broadcom/genet/bcmgenet.c | 45 +++++++++---------- .../net/ethernet/broadcom/genet/bcmgenet.h | 1 + 2 files changed, 22 insertions(+), 24 deletions(-) diff --git a/drivers/net/ethernet/broadcom/genet/bcmgenet.c b/drivers/net/ethernet/broadcom/genet/bcmgenet.c index 84feb241d60b..9137187063f7 100644 --- a/drivers/net/ethernet/broadcom/genet/bcmgenet.c +++ b/drivers/net/ethernet/broadcom/genet/bcmgenet.c @@ -978,39 +978,32 @@ static unsigned int __bcmgenet_tx_reclaim(struct net_device *dev, struct bcmgenet_tx_ring *ring) { struct bcmgenet_priv *priv = netdev_priv(dev); - int last_tx_cn, last_c_index, num_tx_bds; struct enet_cb *tx_cb_ptr; struct netdev_queue *txq; unsigned int pkts_compl = 0; - unsigned int bds_compl; unsigned int c_index; + unsigned int txbds_ready; + unsigned int txbds_processed = 0; /* Compute how many buffers are transmitted since last xmit call */ c_index = bcmgenet_tdma_ring_readl(priv, ring->index, TDMA_CONS_INDEX); - txq = netdev_get_tx_queue(dev, ring->queue); + c_index &= DMA_C_INDEX_MASK; - last_c_index = ring->c_index; - num_tx_bds = ring->size; - - c_index &= (num_tx_bds - 1); - - if (c_index >= last_c_index) - last_tx_cn = c_index - last_c_index; + if (likely(c_index >= ring->c_index)) + txbds_ready = c_index - ring->c_index; else - last_tx_cn = num_tx_bds - last_c_index + c_index; + txbds_ready = (DMA_C_INDEX_MASK + 1) - ring->c_index + c_index; netif_dbg(priv, tx_done, dev, - "%s ring=%d index=%d last_tx_cn=%d last_index=%d\n", - __func__, ring->index, - c_index, last_tx_cn, last_c_index); + "%s ring=%d old_c_index=%u c_index=%u txbds_ready=%u\n", + __func__, ring->index, ring->c_index, c_index, txbds_ready); /* Reclaim transmitted buffers */ - while (last_tx_cn-- > 0) { - tx_cb_ptr = ring->cbs + last_c_index; - bds_compl = 0; + while (txbds_processed < txbds_ready) { + tx_cb_ptr = &priv->tx_cbs[ring->clean_ptr]; if (tx_cb_ptr->skb) { pkts_compl++; - bds_compl = skb_shinfo(tx_cb_ptr->skb)->nr_frags + 1; + dev->stats.tx_packets++; dev->stats.tx_bytes += tx_cb_ptr->skb->len; dma_unmap_single(&dev->dev, dma_unmap_addr(tx_cb_ptr, dma_addr), @@ -1026,20 +1019,23 @@ static unsigned int __bcmgenet_tx_reclaim(struct net_device *dev, DMA_TO_DEVICE); dma_unmap_addr_set(tx_cb_ptr, dma_addr, 0); } - dev->stats.tx_packets++; - ring->free_bds += bds_compl; - last_c_index++; - last_c_index &= (num_tx_bds - 1); + txbds_processed++; + if (likely(ring->clean_ptr < ring->end_ptr)) + ring->clean_ptr++; + else + ring->clean_ptr = ring->cb_ptr; } + ring->free_bds += txbds_processed; + ring->c_index = (ring->c_index + txbds_processed) & DMA_C_INDEX_MASK; + if (ring->free_bds > (MAX_SKB_FRAGS + 1)) { + txq = netdev_get_tx_queue(dev, ring->queue); if (netif_tx_queue_stopped(txq)) netif_tx_wake_queue(txq); } - ring->c_index = c_index; - return pkts_compl; } @@ -1734,6 +1730,7 @@ static void bcmgenet_init_tx_ring(struct bcmgenet_priv *priv, } ring->cbs = priv->tx_cbs + start_ptr; ring->size = size; + ring->clean_ptr = start_ptr; ring->c_index = 0; ring->free_bds = size; ring->write_ptr = start_ptr; diff --git a/drivers/net/ethernet/broadcom/genet/bcmgenet.h b/drivers/net/ethernet/broadcom/genet/bcmgenet.h index 016bd12bf493..548b7e934727 100644 --- a/drivers/net/ethernet/broadcom/genet/bcmgenet.h +++ b/drivers/net/ethernet/broadcom/genet/bcmgenet.h @@ -525,6 +525,7 @@ struct bcmgenet_tx_ring { unsigned int queue; /* queue index */ struct enet_cb *cbs; /* tx ring buffer control block*/ unsigned int size; /* size of each tx ring */ + unsigned int clean_ptr; /* Tx ring clean pointer */ unsigned int c_index; /* last consumer index of each ring*/ unsigned int free_bds; /* # of free bds for each ring */ unsigned int write_ptr; /* Tx ring write pointer SW copy */