From 478a010c9235ca92e66cc5058b42e30e33275ad4 Mon Sep 17 00:00:00 2001 From: Florian Fainelli Date: Mon, 22 Sep 2014 11:54:42 -0700 Subject: [PATCH 1/2] net: bcmgenet: fix TX reclaim accounting for fragments The GENET driver supports SKB fragments, and succeeds in transmitting them properly, but when reclaiming these transmitted fragments, we will only update the count of free buffer descriptors by 1, even for SKBs with fragments. This leads to the networking stack thinking it has more room than the hardware has when pushing new SKBs, and backing off consequently because we return NETDEV_TX_BUSY. Fix this by accounting for the SKB nr_frags plus one (itself) and update ring->free_bds accordingly with that value for each iteration loop in __bcmgenet_tx_reclaim(). Fixes: 1c1008c793fa ("net: bcmgenet: add main driver file") Signed-off-by: Florian Fainelli Signed-off-by: David S. Miller --- drivers/net/ethernet/broadcom/genet/bcmgenet.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/drivers/net/ethernet/broadcom/genet/bcmgenet.c b/drivers/net/ethernet/broadcom/genet/bcmgenet.c index cdef86a03862..11a96437862d 100644 --- a/drivers/net/ethernet/broadcom/genet/bcmgenet.c +++ b/drivers/net/ethernet/broadcom/genet/bcmgenet.c @@ -875,6 +875,7 @@ static void __bcmgenet_tx_reclaim(struct net_device *dev, int last_tx_cn, last_c_index, num_tx_bds; struct enet_cb *tx_cb_ptr; struct netdev_queue *txq; + unsigned int bds_compl; unsigned int c_index; /* Compute how many buffers are transmitted since last xmit call */ @@ -899,7 +900,9 @@ static void __bcmgenet_tx_reclaim(struct net_device *dev, /* Reclaim transmitted buffers */ while (last_tx_cn-- > 0) { tx_cb_ptr = ring->cbs + last_c_index; + bds_compl = 0; if (tx_cb_ptr->skb) { + bds_compl = skb_shinfo(tx_cb_ptr->skb)->nr_frags + 1; dev->stats.tx_bytes += tx_cb_ptr->skb->len; dma_unmap_single(&dev->dev, dma_unmap_addr(tx_cb_ptr, dma_addr), @@ -916,7 +919,7 @@ static void __bcmgenet_tx_reclaim(struct net_device *dev, dma_unmap_addr_set(tx_cb_ptr, dma_addr, 0); } dev->stats.tx_packets++; - ring->free_bds += 1; + ring->free_bds += bds_compl; last_c_index++; last_c_index &= (num_tx_bds - 1); From 4a0c081eff43a11c65dee3ad6c457f7f58bcebe0 Mon Sep 17 00:00:00 2001 From: Florian Fainelli Date: Mon, 22 Sep 2014 11:54:43 -0700 Subject: [PATCH 2/2] net: bcmgenet: call bcmgenet_dma_teardown in bcmgenet_fini_dma We should not be manipulaging the DMA_CTRL registers directly by writing 0 to them to disable DMA. This is an operation that needs to be timed to make sure the DMA engines have been properly stopped since their state machine stops on a packet boundary, not immediately. Make sure that tha bcmgenet_fini_dma() calls bcmgenet_dma_teardown() to ensure a proper DMA engine state. As a result, we need to reorder the function bodies to resolve the use dependency. Fixes: 1c1008c793fa ("net: bcmgenet: add main driver file") Signed-off-by: Florian Fainelli Signed-off-by: David S. Miller --- .../net/ethernet/broadcom/genet/bcmgenet.c | 105 +++++++++--------- 1 file changed, 52 insertions(+), 53 deletions(-) diff --git a/drivers/net/ethernet/broadcom/genet/bcmgenet.c b/drivers/net/ethernet/broadcom/genet/bcmgenet.c index 11a96437862d..5cc9cae21ed5 100644 --- a/drivers/net/ethernet/broadcom/genet/bcmgenet.c +++ b/drivers/net/ethernet/broadcom/genet/bcmgenet.c @@ -1744,13 +1744,63 @@ static void bcmgenet_init_multiq(struct net_device *dev) bcmgenet_tdma_writel(priv, reg, DMA_CTRL); } +static int bcmgenet_dma_teardown(struct bcmgenet_priv *priv) +{ + int ret = 0; + int timeout = 0; + u32 reg; + + /* Disable TDMA to stop add more frames in TX DMA */ + reg = bcmgenet_tdma_readl(priv, DMA_CTRL); + reg &= ~DMA_EN; + bcmgenet_tdma_writel(priv, reg, DMA_CTRL); + + /* Check TDMA status register to confirm TDMA is disabled */ + while (timeout++ < DMA_TIMEOUT_VAL) { + reg = bcmgenet_tdma_readl(priv, DMA_STATUS); + if (reg & DMA_DISABLED) + break; + + udelay(1); + } + + if (timeout == DMA_TIMEOUT_VAL) { + netdev_warn(priv->dev, "Timed out while disabling TX DMA\n"); + ret = -ETIMEDOUT; + } + + /* Wait 10ms for packet drain in both tx and rx dma */ + usleep_range(10000, 20000); + + /* Disable RDMA */ + reg = bcmgenet_rdma_readl(priv, DMA_CTRL); + reg &= ~DMA_EN; + bcmgenet_rdma_writel(priv, reg, DMA_CTRL); + + timeout = 0; + /* Check RDMA status register to confirm RDMA is disabled */ + while (timeout++ < DMA_TIMEOUT_VAL) { + reg = bcmgenet_rdma_readl(priv, DMA_STATUS); + if (reg & DMA_DISABLED) + break; + + udelay(1); + } + + if (timeout == DMA_TIMEOUT_VAL) { + netdev_warn(priv->dev, "Timed out while disabling RX DMA\n"); + ret = -ETIMEDOUT; + } + + return ret; +} + static void bcmgenet_fini_dma(struct bcmgenet_priv *priv) { int i; /* disable DMA */ - bcmgenet_rdma_writel(priv, 0, DMA_CTRL); - bcmgenet_tdma_writel(priv, 0, DMA_CTRL); + bcmgenet_dma_teardown(priv); for (i = 0; i < priv->num_tx_bds; i++) { if (priv->tx_cbs[i].skb != NULL) { @@ -2109,57 +2159,6 @@ err_clk_disable: return ret; } -static int bcmgenet_dma_teardown(struct bcmgenet_priv *priv) -{ - int ret = 0; - int timeout = 0; - u32 reg; - - /* Disable TDMA to stop add more frames in TX DMA */ - reg = bcmgenet_tdma_readl(priv, DMA_CTRL); - reg &= ~DMA_EN; - bcmgenet_tdma_writel(priv, reg, DMA_CTRL); - - /* Check TDMA status register to confirm TDMA is disabled */ - while (timeout++ < DMA_TIMEOUT_VAL) { - reg = bcmgenet_tdma_readl(priv, DMA_STATUS); - if (reg & DMA_DISABLED) - break; - - udelay(1); - } - - if (timeout == DMA_TIMEOUT_VAL) { - netdev_warn(priv->dev, "Timed out while disabling TX DMA\n"); - ret = -ETIMEDOUT; - } - - /* Wait 10ms for packet drain in both tx and rx dma */ - usleep_range(10000, 20000); - - /* Disable RDMA */ - reg = bcmgenet_rdma_readl(priv, DMA_CTRL); - reg &= ~DMA_EN; - bcmgenet_rdma_writel(priv, reg, DMA_CTRL); - - timeout = 0; - /* Check RDMA status register to confirm RDMA is disabled */ - while (timeout++ < DMA_TIMEOUT_VAL) { - reg = bcmgenet_rdma_readl(priv, DMA_STATUS); - if (reg & DMA_DISABLED) - break; - - udelay(1); - } - - if (timeout == DMA_TIMEOUT_VAL) { - netdev_warn(priv->dev, "Timed out while disabling RX DMA\n"); - ret = -ETIMEDOUT; - } - - return ret; -} - static void bcmgenet_netif_stop(struct net_device *dev) { struct bcmgenet_priv *priv = netdev_priv(dev);