From 16958a2b05def4ed214ae681b7ee4ce8537b00fb Mon Sep 17 00:00:00 2001 From: "Lendacky, Thomas" Date: Thu, 20 Nov 2014 11:04:08 -0600 Subject: [PATCH] amd-xgbe: Add support for the skb->xmit_more flag Add support to delay telling the hardware about data that is ready to be transmitted if the skb->xmit_more flag is set. Signed-off-by: Tom Lendacky Signed-off-by: David S. Miller --- drivers/net/ethernet/amd/xgbe/xgbe-desc.c | 5 ++- drivers/net/ethernet/amd/xgbe/xgbe-dev.c | 43 ++++++++++++++++------- drivers/net/ethernet/amd/xgbe/xgbe-drv.c | 37 +++++++++++++++---- drivers/net/ethernet/amd/xgbe/xgbe.h | 15 ++++++++ 4 files changed, 78 insertions(+), 22 deletions(-) diff --git a/drivers/net/ethernet/amd/xgbe/xgbe-desc.c b/drivers/net/ethernet/amd/xgbe/xgbe-desc.c index 62cb4d3388df..51b68d1299fe 100644 --- a/drivers/net/ethernet/amd/xgbe/xgbe-desc.c +++ b/drivers/net/ethernet/amd/xgbe/xgbe-desc.c @@ -378,7 +378,7 @@ static void xgbe_wrapper_tx_descriptor_init(struct xgbe_prv_data *pdata) ring->cur = 0; ring->dirty = 0; - ring->tx.queue_stopped = 0; + memset(&ring->tx, 0, sizeof(ring->tx)); hw_if->tx_desc_init(channel); } @@ -422,8 +422,7 @@ static void xgbe_wrapper_rx_descriptor_init(struct xgbe_prv_data *pdata) ring->cur = 0; ring->dirty = 0; - ring->rx.realloc_index = 0; - ring->rx.realloc_threshold = 0; + memset(&ring->rx, 0, sizeof(ring->rx)); hw_if->rx_desc_init(channel); } diff --git a/drivers/net/ethernet/amd/xgbe/xgbe-dev.c b/drivers/net/ethernet/amd/xgbe/xgbe-dev.c index b3d2433b52bb..53f5f66ec2ee 100644 --- a/drivers/net/ethernet/amd/xgbe/xgbe-dev.c +++ b/drivers/net/ethernet/amd/xgbe/xgbe-dev.c @@ -1325,6 +1325,29 @@ static void xgbe_config_dcb_pfc(struct xgbe_prv_data *pdata) xgbe_config_flow_control(pdata); } +static void xgbe_tx_start_xmit(struct xgbe_channel *channel, + struct xgbe_ring *ring) +{ + struct xgbe_prv_data *pdata = channel->pdata; + struct xgbe_ring_data *rdata; + + /* Issue a poll command to Tx DMA by writing address + * of next immediate free descriptor */ + rdata = XGBE_GET_DESC_DATA(ring, ring->cur); + XGMAC_DMA_IOWRITE(channel, DMA_CH_TDTR_LO, + lower_32_bits(rdata->rdesc_dma)); + + /* Start the Tx coalescing timer */ + if (pdata->tx_usecs && !channel->tx_timer_active) { + channel->tx_timer_active = 1; + hrtimer_start(&channel->tx_timer, + ktime_set(0, pdata->tx_usecs * NSEC_PER_USEC), + HRTIMER_MODE_REL); + } + + ring->tx.xmit_more = 0; +} + static void xgbe_dev_xmit(struct xgbe_channel *channel) { struct xgbe_prv_data *pdata = channel->pdata; @@ -1528,20 +1551,13 @@ static void xgbe_dev_xmit(struct xgbe_channel *channel) /* Make sure ownership is written to the descriptor */ wmb(); - /* Issue a poll command to Tx DMA by writing address - * of next immediate free descriptor */ ring->cur++; - rdata = XGBE_GET_DESC_DATA(ring, ring->cur); - XGMAC_DMA_IOWRITE(channel, DMA_CH_TDTR_LO, - lower_32_bits(rdata->rdesc_dma)); - - /* Start the Tx coalescing timer */ - if (pdata->tx_usecs && !channel->tx_timer_active) { - channel->tx_timer_active = 1; - hrtimer_start(&channel->tx_timer, - ktime_set(0, pdata->tx_usecs * NSEC_PER_USEC), - HRTIMER_MODE_REL); - } + if (!packet->skb->xmit_more || + netif_xmit_stopped(netdev_get_tx_queue(pdata->netdev, + channel->queue_index))) + xgbe_tx_start_xmit(channel, ring); + else + ring->tx.xmit_more = 1; DBGPR(" %s: descriptors %u to %u written\n", channel->name, start_index & (ring->rdesc_count - 1), @@ -2802,6 +2818,7 @@ void xgbe_init_function_ptrs_dev(struct xgbe_hw_if *hw_if) hw_if->rx_desc_reset = xgbe_rx_desc_reset; hw_if->is_last_desc = xgbe_is_last_desc; hw_if->is_context_desc = xgbe_is_context_desc; + hw_if->tx_start_xmit = xgbe_tx_start_xmit; /* For FLOW ctrl */ hw_if->config_tx_flow_control = xgbe_config_tx_flow_control; diff --git a/drivers/net/ethernet/amd/xgbe/xgbe-drv.c b/drivers/net/ethernet/amd/xgbe/xgbe-drv.c index f9635281c7df..02c104dc2aa4 100644 --- a/drivers/net/ethernet/amd/xgbe/xgbe-drv.c +++ b/drivers/net/ethernet/amd/xgbe/xgbe-drv.c @@ -225,6 +225,28 @@ static inline unsigned int xgbe_tx_avail_desc(struct xgbe_ring *ring) return (ring->rdesc_count - (ring->cur - ring->dirty)); } +static int xgbe_maybe_stop_tx_queue(struct xgbe_channel *channel, + struct xgbe_ring *ring, unsigned int count) +{ + struct xgbe_prv_data *pdata = channel->pdata; + + if (count > xgbe_tx_avail_desc(ring)) { + DBGPR(" Tx queue stopped, not enough descriptors available\n"); + netif_stop_subqueue(pdata->netdev, channel->queue_index); + ring->tx.queue_stopped = 1; + + /* If we haven't notified the hardware because of xmit_more + * support, tell it now + */ + if (ring->tx.xmit_more) + pdata->hw_if.tx_start_xmit(channel, ring); + + return NETDEV_TX_BUSY; + } + + return 0; +} + static int xgbe_calc_rx_buf_size(struct net_device *netdev, unsigned int mtu) { unsigned int rx_buf_size; @@ -1199,6 +1221,8 @@ static void xgbe_packet_info(struct xgbe_prv_data *pdata, unsigned int len; unsigned int i; + packet->skb = skb; + context_desc = 0; packet->rdesc_count = 0; @@ -1447,13 +1471,9 @@ static int xgbe_xmit(struct sk_buff *skb, struct net_device *netdev) xgbe_packet_info(pdata, ring, skb, packet); /* Check that there are enough descriptors available */ - if (packet->rdesc_count > xgbe_tx_avail_desc(ring)) { - DBGPR(" Tx queue stopped, not enough descriptors available\n"); - netif_stop_subqueue(netdev, channel->queue_index); - ring->tx.queue_stopped = 1; - ret = NETDEV_TX_BUSY; + ret = xgbe_maybe_stop_tx_queue(channel, ring, packet->rdesc_count); + if (ret) goto tx_netdev_return; - } ret = xgbe_prep_tso(skb, packet); if (ret) { @@ -1480,6 +1500,11 @@ static int xgbe_xmit(struct sk_buff *skb, struct net_device *netdev) xgbe_print_pkt(netdev, skb, true); #endif + /* Stop the queue in advance if there may not be enough descriptors */ + xgbe_maybe_stop_tx_queue(channel, ring, XGBE_TX_MAX_DESCS); + + ret = NETDEV_TX_OK; + tx_netdev_return: spin_unlock_irqrestore(&ring->lock, flags); diff --git a/drivers/net/ethernet/amd/xgbe/xgbe.h b/drivers/net/ethernet/amd/xgbe/xgbe.h index ec0d37a917ae..eb3387398c6f 100644 --- a/drivers/net/ethernet/amd/xgbe/xgbe.h +++ b/drivers/net/ethernet/amd/xgbe/xgbe.h @@ -140,6 +140,17 @@ #define XGBE_TX_MAX_BUF_SIZE (0x3fff & ~(64 - 1)) +/* Descriptors required for maximum contigous TSO/GSO packet */ +#define XGBE_TX_MAX_SPLIT ((GSO_MAX_SIZE / XGBE_TX_MAX_BUF_SIZE) + 1) + +/* Maximum possible descriptors needed for an SKB: + * - Maximum number of SKB frags + * - Maximum descriptors for contiguous TSO/GSO packet + * - Possible context descriptor + * - Possible TSO header descriptor + */ +#define XGBE_TX_MAX_DESCS (MAX_SKB_FRAGS + XGBE_TX_MAX_SPLIT + 2) + #define XGBE_RX_MIN_BUF_SIZE (ETH_FRAME_LEN + ETH_FCS_LEN + VLAN_HLEN) #define XGBE_RX_BUF_ALIGN 64 #define XGBE_SKB_ALLOC_SIZE 256 @@ -225,6 +236,8 @@ struct xgbe_prv_data; struct xgbe_packet_data { + struct sk_buff *skb; + unsigned int attributes; unsigned int errors; @@ -360,6 +373,7 @@ struct xgbe_ring { union { struct { unsigned int queue_stopped; + unsigned int xmit_more; unsigned short cur_mss; unsigned short cur_vlan_ctag; } tx; @@ -523,6 +537,7 @@ struct xgbe_hw_if { void (*tx_desc_reset)(struct xgbe_ring_data *); int (*is_last_desc)(struct xgbe_ring_desc *); int (*is_context_desc)(struct xgbe_ring_desc *); + void (*tx_start_xmit)(struct xgbe_channel *, struct xgbe_ring *); /* For FLOW ctrl */ int (*config_tx_flow_control)(struct xgbe_prv_data *);