From 1943d8ba9507d49fa5cdb51eb1b63810d94e1969 Mon Sep 17 00:00:00 2001 From: Jesse Brandeburg Date: Fri, 14 Feb 2014 02:14:40 +0000 Subject: [PATCH] i40e/i40evf: enable hardware feature head write back The hardware supports a feature to avoid updating the descriptor ring by marking each descriptor with a DD bit, and instead writes a memory location with an update to where the driver should clean up to. Enable this feature. Change-ID: I5da4e0681f0b581a6401c950a81808792267fe57 Signed-off-by: Jesse Brandeburg Signed-off-by: Mitch Williams Signed-off-by: Catherine Sullivan Tested-by: Kavindya Deegala Signed-off-by: Jeff Kirsher --- drivers/net/ethernet/intel/i40e/i40e_main.c | 5 ++ drivers/net/ethernet/intel/i40e/i40e_txrx.c | 46 ++++++++++++++++--- .../ethernet/intel/i40e/i40e_virtchnl_pf.c | 3 ++ drivers/net/ethernet/intel/i40evf/i40e_txrx.c | 46 ++++++++++++++++--- 4 files changed, 88 insertions(+), 12 deletions(-) diff --git a/drivers/net/ethernet/intel/i40e/i40e_main.c b/drivers/net/ethernet/intel/i40e/i40e_main.c index 661cd427bce6..95433d4d2f6a 100644 --- a/drivers/net/ethernet/intel/i40e/i40e_main.c +++ b/drivers/net/ethernet/intel/i40e/i40e_main.c @@ -2181,6 +2181,11 @@ static int i40e_configure_tx_ring(struct i40e_ring *ring) tx_ctx.fd_ena = !!(vsi->back->flags & (I40E_FLAG_FD_SB_ENABLED | I40E_FLAG_FD_ATR_ENABLED)); tx_ctx.timesync_ena = !!(vsi->back->flags & I40E_FLAG_PTP); + /* FDIR VSI tx ring can still use RS bit and writebacks */ + if (vsi->type != I40E_VSI_FDIR) + tx_ctx.head_wb_ena = 1; + tx_ctx.head_wb_addr = ring->dma + + (ring->count * sizeof(struct i40e_tx_desc)); /* As part of VSI creation/update, FW allocates certain * Tx arbitration queue sets for each TC enabled for diff --git a/drivers/net/ethernet/intel/i40e/i40e_txrx.c b/drivers/net/ethernet/intel/i40e/i40e_txrx.c index 88666adb0743..079c6b2bafc3 100644 --- a/drivers/net/ethernet/intel/i40e/i40e_txrx.c +++ b/drivers/net/ethernet/intel/i40e/i40e_txrx.c @@ -618,6 +618,20 @@ static bool i40e_check_tx_hang(struct i40e_ring *tx_ring) return ret; } +/** + * i40e_get_head - Retrieve head from head writeback + * @tx_ring: tx ring to fetch head of + * + * Returns value of Tx ring head based on value stored + * in head write-back location + **/ +static inline u32 i40e_get_head(struct i40e_ring *tx_ring) +{ + void *head = (struct i40e_tx_desc *)tx_ring->desc + tx_ring->count; + + return le32_to_cpu(*(volatile __le32 *)head); +} + /** * i40e_clean_tx_irq - Reclaim resources after transmit completes * @tx_ring: tx ring to clean @@ -629,6 +643,7 @@ static bool i40e_clean_tx_irq(struct i40e_ring *tx_ring, int budget) { u16 i = tx_ring->next_to_clean; struct i40e_tx_buffer *tx_buf; + struct i40e_tx_desc *tx_head; struct i40e_tx_desc *tx_desc; unsigned int total_packets = 0; unsigned int total_bytes = 0; @@ -637,6 +652,8 @@ static bool i40e_clean_tx_irq(struct i40e_ring *tx_ring, int budget) tx_desc = I40E_TX_DESC(tx_ring, i); i -= tx_ring->count; + tx_head = I40E_TX_DESC(tx_ring, i40e_get_head(tx_ring)); + do { struct i40e_tx_desc *eop_desc = tx_buf->next_to_watch; @@ -647,9 +664,8 @@ static bool i40e_clean_tx_irq(struct i40e_ring *tx_ring, int budget) /* prevent any other reads prior to eop_desc */ read_barrier_depends(); - /* if the descriptor isn't done, no work yet to do */ - if (!(eop_desc->cmd_type_offset_bsz & - cpu_to_le64(I40E_TX_DESC_DTYPE_DESC_DONE))) + /* we have caught up to head, no work left to do */ + if (tx_head == tx_desc) break; /* clear next_to_watch to prevent false hangs */ @@ -905,6 +921,10 @@ int i40e_setup_tx_descriptors(struct i40e_ring *tx_ring) /* round up to nearest 4K */ tx_ring->size = tx_ring->count * sizeof(struct i40e_tx_desc); + /* add u32 for head writeback, align after this takes care of + * guaranteeing this is at least one cache line in size + */ + tx_ring->size += sizeof(u32); tx_ring->size = ALIGN(tx_ring->size, 4096); tx_ring->desc = dma_alloc_coherent(dev, tx_ring->size, &tx_ring->dma, GFP_KERNEL); @@ -2042,9 +2062,23 @@ static void i40e_tx_map(struct i40e_ring *tx_ring, struct sk_buff *skb, tx_bi = &tx_ring->tx_bi[i]; } - tx_desc->cmd_type_offset_bsz = - build_ctob(td_cmd, td_offset, size, td_tag) | - cpu_to_le64((u64)I40E_TXD_CMD << I40E_TXD_QW1_CMD_SHIFT); + /* Place RS bit on last descriptor of any packet that spans across the + * 4th descriptor (WB_STRIDE aka 0x3) in a 64B cacheline. + */ +#define WB_STRIDE 0x3 + if (((i & WB_STRIDE) != WB_STRIDE) && + (first <= &tx_ring->tx_bi[i]) && + (first >= &tx_ring->tx_bi[i & ~WB_STRIDE])) { + tx_desc->cmd_type_offset_bsz = + build_ctob(td_cmd, td_offset, size, td_tag) | + cpu_to_le64((u64)I40E_TX_DESC_CMD_EOP << + I40E_TXD_QW1_CMD_SHIFT); + } else { + tx_desc->cmd_type_offset_bsz = + build_ctob(td_cmd, td_offset, size, td_tag) | + cpu_to_le64((u64)I40E_TXD_CMD << + I40E_TXD_QW1_CMD_SHIFT); + } netdev_tx_sent_queue(netdev_get_tx_queue(tx_ring->netdev, tx_ring->queue_index), diff --git a/drivers/net/ethernet/intel/i40e/i40e_virtchnl_pf.c b/drivers/net/ethernet/intel/i40e/i40e_virtchnl_pf.c index 2086a62062c2..b2da079cd696 100644 --- a/drivers/net/ethernet/intel/i40e/i40e_virtchnl_pf.c +++ b/drivers/net/ethernet/intel/i40e/i40e_virtchnl_pf.c @@ -230,6 +230,9 @@ static int i40e_config_vsi_tx_queue(struct i40e_vf *vf, u16 vsi_idx, tx_ctx.qlen = info->ring_len; tx_ctx.rdylist = le16_to_cpu(pf->vsi[vsi_idx]->info.qs_handle[0]); tx_ctx.rdylist_act = 0; + tx_ctx.head_wb_ena = 1; + tx_ctx.head_wb_addr = info->dma_ring_addr + + (info->ring_len * sizeof(struct i40e_tx_desc)); /* clear the context in the HMC */ ret = i40e_clear_lan_tx_queue_context(hw, pf_queue_id); diff --git a/drivers/net/ethernet/intel/i40evf/i40e_txrx.c b/drivers/net/ethernet/intel/i40evf/i40e_txrx.c index b1d87c6a5c35..626c08a98edb 100644 --- a/drivers/net/ethernet/intel/i40evf/i40e_txrx.c +++ b/drivers/net/ethernet/intel/i40evf/i40e_txrx.c @@ -169,6 +169,20 @@ static bool i40e_check_tx_hang(struct i40e_ring *tx_ring) return ret; } +/** + * i40e_get_head - Retrieve head from head writeback + * @tx_ring: tx ring to fetch head of + * + * Returns value of Tx ring head based on value stored + * in head write-back location + **/ +static inline u32 i40e_get_head(struct i40e_ring *tx_ring) +{ + void *head = (struct i40e_tx_desc *)tx_ring->desc + tx_ring->count; + + return le32_to_cpu(*(volatile __le32 *)head); +} + /** * i40e_clean_tx_irq - Reclaim resources after transmit completes * @tx_ring: tx ring to clean @@ -180,6 +194,7 @@ static bool i40e_clean_tx_irq(struct i40e_ring *tx_ring, int budget) { u16 i = tx_ring->next_to_clean; struct i40e_tx_buffer *tx_buf; + struct i40e_tx_desc *tx_head; struct i40e_tx_desc *tx_desc; unsigned int total_packets = 0; unsigned int total_bytes = 0; @@ -188,6 +203,8 @@ static bool i40e_clean_tx_irq(struct i40e_ring *tx_ring, int budget) tx_desc = I40E_TX_DESC(tx_ring, i); i -= tx_ring->count; + tx_head = I40E_TX_DESC(tx_ring, i40e_get_head(tx_ring)); + do { struct i40e_tx_desc *eop_desc = tx_buf->next_to_watch; @@ -198,9 +215,8 @@ static bool i40e_clean_tx_irq(struct i40e_ring *tx_ring, int budget) /* prevent any other reads prior to eop_desc */ read_barrier_depends(); - /* if the descriptor isn't done, no work yet to do */ - if (!(eop_desc->cmd_type_offset_bsz & - cpu_to_le64(I40E_TX_DESC_DTYPE_DESC_DONE))) + /* we have caught up to head, no work left to do */ + if (tx_head == tx_desc) break; /* clear next_to_watch to prevent false hangs */ @@ -432,6 +448,10 @@ int i40evf_setup_tx_descriptors(struct i40e_ring *tx_ring) /* round up to nearest 4K */ tx_ring->size = tx_ring->count * sizeof(struct i40e_tx_desc); + /* add u32 for head writeback, align after this takes care of + * guaranteeing this is at least one cache line in size + */ + tx_ring->size += sizeof(u32); tx_ring->size = ALIGN(tx_ring->size, 4096); tx_ring->desc = dma_alloc_coherent(dev, tx_ring->size, &tx_ring->dma, GFP_KERNEL); @@ -1377,9 +1397,23 @@ static void i40e_tx_map(struct i40e_ring *tx_ring, struct sk_buff *skb, tx_bi = &tx_ring->tx_bi[i]; } - tx_desc->cmd_type_offset_bsz = - build_ctob(td_cmd, td_offset, size, td_tag) | - cpu_to_le64((u64)I40E_TXD_CMD << I40E_TXD_QW1_CMD_SHIFT); + /* Place RS bit on last descriptor of any packet that spans across the + * 4th descriptor (WB_STRIDE aka 0x3) in a 64B cacheline. + */ +#define WB_STRIDE 0x3 + if (((i & WB_STRIDE) != WB_STRIDE) && + (first <= &tx_ring->tx_bi[i]) && + (first >= &tx_ring->tx_bi[i & ~WB_STRIDE])) { + tx_desc->cmd_type_offset_bsz = + build_ctob(td_cmd, td_offset, size, td_tag) | + cpu_to_le64((u64)I40E_TX_DESC_CMD_EOP << + I40E_TXD_QW1_CMD_SHIFT); + } else { + tx_desc->cmd_type_offset_bsz = + build_ctob(td_cmd, td_offset, size, td_tag) | + cpu_to_le64((u64)I40E_TXD_CMD << + I40E_TXD_QW1_CMD_SHIFT); + } netdev_tx_sent_queue(netdev_get_tx_queue(tx_ring->netdev, tx_ring->queue_index), -- 2.20.1