diff options
Diffstat (limited to 'drivers/net/ethernet/intel/i40evf/i40e_txrx.c')
| -rw-r--r-- | drivers/net/ethernet/intel/i40evf/i40e_txrx.c | 2510 |
1 files changed, 2510 insertions, 0 deletions
diff --git a/drivers/net/ethernet/intel/i40evf/i40e_txrx.c b/drivers/net/ethernet/intel/i40evf/i40e_txrx.c new file mode 100644 index 000000000..b56d22b53 --- /dev/null +++ b/drivers/net/ethernet/intel/i40evf/i40e_txrx.c @@ -0,0 +1,2510 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Copyright(c) 2013 - 2018 Intel Corporation. */ + +#include <linux/prefetch.h> +#include <net/busy_poll.h> + +#include "i40evf.h" +#include "i40e_trace.h" +#include "i40e_prototype.h" + +static inline __le64 build_ctob(u32 td_cmd, u32 td_offset, unsigned int size, + u32 td_tag) +{ + return cpu_to_le64(I40E_TX_DESC_DTYPE_DATA | + ((u64)td_cmd << I40E_TXD_QW1_CMD_SHIFT) | + ((u64)td_offset << I40E_TXD_QW1_OFFSET_SHIFT) | + ((u64)size << I40E_TXD_QW1_TX_BUF_SZ_SHIFT) | + ((u64)td_tag << I40E_TXD_QW1_L2TAG1_SHIFT)); +} + +#define I40E_TXD_CMD (I40E_TX_DESC_CMD_EOP | I40E_TX_DESC_CMD_RS) + +/** + * i40e_unmap_and_free_tx_resource - Release a Tx buffer + * @ring: the ring that owns the buffer + * @tx_buffer: the buffer to free + **/ +static void i40e_unmap_and_free_tx_resource(struct i40e_ring *ring, + struct i40e_tx_buffer *tx_buffer) +{ + if (tx_buffer->skb) { + if (tx_buffer->tx_flags & I40E_TX_FLAGS_FD_SB) + kfree(tx_buffer->raw_buf); + else + dev_kfree_skb_any(tx_buffer->skb); + if (dma_unmap_len(tx_buffer, len)) + dma_unmap_single(ring->dev, + dma_unmap_addr(tx_buffer, dma), + dma_unmap_len(tx_buffer, len), + DMA_TO_DEVICE); + } else if (dma_unmap_len(tx_buffer, len)) { + dma_unmap_page(ring->dev, + dma_unmap_addr(tx_buffer, dma), + dma_unmap_len(tx_buffer, len), + DMA_TO_DEVICE); + } + + tx_buffer->next_to_watch = NULL; + tx_buffer->skb = NULL; + dma_unmap_len_set(tx_buffer, len, 0); + /* tx_buffer must be completely set up in the transmit path */ +} + +/** + * i40evf_clean_tx_ring - Free any empty Tx buffers + * @tx_ring: ring to be cleaned + **/ +void i40evf_clean_tx_ring(struct i40e_ring *tx_ring) +{ + unsigned long bi_size; + u16 i; + + /* ring already cleared, nothing to do */ + if (!tx_ring->tx_bi) + return; + + /* Free all the Tx ring sk_buffs */ + for (i = 0; i < tx_ring->count; i++) + i40e_unmap_and_free_tx_resource(tx_ring, &tx_ring->tx_bi[i]); + + bi_size = sizeof(struct i40e_tx_buffer) * tx_ring->count; + memset(tx_ring->tx_bi, 0, bi_size); + + /* Zero out the descriptor ring */ + memset(tx_ring->desc, 0, tx_ring->size); + + tx_ring->next_to_use = 0; + tx_ring->next_to_clean = 0; + + if (!tx_ring->netdev) + return; + + /* cleanup Tx queue statistics */ + netdev_tx_reset_queue(txring_txq(tx_ring)); +} + +/** + * i40evf_free_tx_resources - Free Tx resources per queue + * @tx_ring: Tx descriptor ring for a specific queue + * + * Free all transmit software resources + **/ +void i40evf_free_tx_resources(struct i40e_ring *tx_ring) +{ + i40evf_clean_tx_ring(tx_ring); + kfree(tx_ring->tx_bi); + tx_ring->tx_bi = NULL; + + if (tx_ring->desc) { + dma_free_coherent(tx_ring->dev, tx_ring->size, + tx_ring->desc, tx_ring->dma); + tx_ring->desc = NULL; + } +} + +/** + * i40evf_get_tx_pending - how many Tx descriptors not processed + * @ring: the ring of descriptors + * @in_sw: is tx_pending being checked in SW or HW + * + * Since there is no access to the ring head register + * in XL710, we need to use our local copies + **/ +u32 i40evf_get_tx_pending(struct i40e_ring *ring, bool in_sw) +{ + u32 head, tail; + + head = ring->next_to_clean; + tail = readl(ring->tail); + + if (head != tail) + return (head < tail) ? + tail - head : (tail + ring->count - head); + + return 0; +} + +/** + * i40evf_detect_recover_hung - Function to detect and recover hung_queues + * @vsi: pointer to vsi struct with tx queues + * + * VSI has netdev and netdev has TX queues. This function is to check each of + * those TX queues if they are hung, trigger recovery by issuing SW interrupt. + **/ +void i40evf_detect_recover_hung(struct i40e_vsi *vsi) +{ + struct i40e_ring *tx_ring = NULL; + struct net_device *netdev; + unsigned int i; + int packets; + + if (!vsi) + return; + + if (test_bit(__I40E_VSI_DOWN, vsi->state)) + return; + + netdev = vsi->netdev; + if (!netdev) + return; + + if (!netif_carrier_ok(netdev)) + return; + + for (i = 0; i < vsi->back->num_active_queues; i++) { + tx_ring = &vsi->back->tx_rings[i]; + if (tx_ring && tx_ring->desc) { + /* If packet counter has not changed the queue is + * likely stalled, so force an interrupt for this + * queue. + * + * prev_pkt_ctr would be negative if there was no + * pending work. + */ + packets = tx_ring->stats.packets & INT_MAX; + if (tx_ring->tx_stats.prev_pkt_ctr == packets) { + i40evf_force_wb(vsi, tx_ring->q_vector); + continue; + } + + /* Memory barrier between read of packet count and call + * to i40evf_get_tx_pending() + */ + smp_rmb(); + tx_ring->tx_stats.prev_pkt_ctr = + i40evf_get_tx_pending(tx_ring, true) ? packets : -1; + } + } +} + +#define WB_STRIDE 4 + +/** + * i40e_clean_tx_irq - Reclaim resources after transmit completes + * @vsi: the VSI we care about + * @tx_ring: Tx ring to clean + * @napi_budget: Used to determine if we are in netpoll + * + * Returns true if there's any budget left (e.g. the clean is finished) + **/ +static bool i40e_clean_tx_irq(struct i40e_vsi *vsi, + struct i40e_ring *tx_ring, int napi_budget) +{ + u16 i = tx_ring->next_to_clean; + struct i40e_tx_buffer *tx_buf; + struct i40e_tx_desc *tx_desc; + unsigned int total_bytes = 0, total_packets = 0; + unsigned int budget = vsi->work_limit; + + tx_buf = &tx_ring->tx_bi[i]; + tx_desc = I40E_TX_DESC(tx_ring, i); + i -= tx_ring->count; + + do { + struct i40e_tx_desc *eop_desc = tx_buf->next_to_watch; + + /* if next_to_watch is not set then there is no work pending */ + if (!eop_desc) + break; + + /* prevent any other reads prior to eop_desc */ + smp_rmb(); + + i40e_trace(clean_tx_irq, tx_ring, tx_desc, tx_buf); + /* 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))) + break; + + /* clear next_to_watch to prevent false hangs */ + tx_buf->next_to_watch = NULL; + + /* update the statistics for this packet */ + total_bytes += tx_buf->bytecount; + total_packets += tx_buf->gso_segs; + + /* free the skb */ + napi_consume_skb(tx_buf->skb, napi_budget); + + /* unmap skb header data */ + dma_unmap_single(tx_ring->dev, + dma_unmap_addr(tx_buf, dma), + dma_unmap_len(tx_buf, len), + DMA_TO_DEVICE); + + /* clear tx_buffer data */ + tx_buf->skb = NULL; + dma_unmap_len_set(tx_buf, len, 0); + + /* unmap remaining buffers */ + while (tx_desc != eop_desc) { + i40e_trace(clean_tx_irq_unmap, + tx_ring, tx_desc, tx_buf); + + tx_buf++; + tx_desc++; + i++; + if (unlikely(!i)) { + i -= tx_ring->count; + tx_buf = tx_ring->tx_bi; + tx_desc = I40E_TX_DESC(tx_ring, 0); + } + + /* unmap any remaining paged data */ + if (dma_unmap_len(tx_buf, len)) { + dma_unmap_page(tx_ring->dev, + dma_unmap_addr(tx_buf, dma), + dma_unmap_len(tx_buf, len), + DMA_TO_DEVICE); + dma_unmap_len_set(tx_buf, len, 0); + } + } + + /* move us one more past the eop_desc for start of next pkt */ + tx_buf++; + tx_desc++; + i++; + if (unlikely(!i)) { + i -= tx_ring->count; + tx_buf = tx_ring->tx_bi; + tx_desc = I40E_TX_DESC(tx_ring, 0); + } + + prefetch(tx_desc); + + /* update budget accounting */ + budget--; + } while (likely(budget)); + + i += tx_ring->count; + tx_ring->next_to_clean = i; + u64_stats_update_begin(&tx_ring->syncp); + tx_ring->stats.bytes += total_bytes; + tx_ring->stats.packets += total_packets; + u64_stats_update_end(&tx_ring->syncp); + tx_ring->q_vector->tx.total_bytes += total_bytes; + tx_ring->q_vector->tx.total_packets += total_packets; + + if (tx_ring->flags & I40E_TXR_FLAGS_WB_ON_ITR) { + /* check to see if there are < 4 descriptors + * waiting to be written back, then kick the hardware to force + * them to be written back in case we stay in NAPI. + * In this mode on X722 we do not enable Interrupt. + */ + unsigned int j = i40evf_get_tx_pending(tx_ring, false); + + if (budget && + ((j / WB_STRIDE) == 0) && (j > 0) && + !test_bit(__I40E_VSI_DOWN, vsi->state) && + (I40E_DESC_UNUSED(tx_ring) != tx_ring->count)) + tx_ring->arm_wb = true; + } + + /* notify netdev of completed buffers */ + netdev_tx_completed_queue(txring_txq(tx_ring), + total_packets, total_bytes); + +#define TX_WAKE_THRESHOLD ((s16)(DESC_NEEDED * 2)) + if (unlikely(total_packets && netif_carrier_ok(tx_ring->netdev) && + (I40E_DESC_UNUSED(tx_ring) >= TX_WAKE_THRESHOLD))) { + /* Make sure that anybody stopping the queue after this + * sees the new next_to_clean. + */ + smp_mb(); + if (__netif_subqueue_stopped(tx_ring->netdev, + tx_ring->queue_index) && + !test_bit(__I40E_VSI_DOWN, vsi->state)) { + netif_wake_subqueue(tx_ring->netdev, + tx_ring->queue_index); + ++tx_ring->tx_stats.restart_queue; + } + } + + return !!budget; +} + +/** + * i40evf_enable_wb_on_itr - Arm hardware to do a wb, interrupts are not enabled + * @vsi: the VSI we care about + * @q_vector: the vector on which to enable writeback + * + **/ +static void i40e_enable_wb_on_itr(struct i40e_vsi *vsi, + struct i40e_q_vector *q_vector) +{ + u16 flags = q_vector->tx.ring[0].flags; + u32 val; + + if (!(flags & I40E_TXR_FLAGS_WB_ON_ITR)) + return; + + if (q_vector->arm_wb_state) + return; + + val = I40E_VFINT_DYN_CTLN1_WB_ON_ITR_MASK | + I40E_VFINT_DYN_CTLN1_ITR_INDX_MASK; /* set noitr */ + + wr32(&vsi->back->hw, + I40E_VFINT_DYN_CTLN1(q_vector->reg_idx), val); + q_vector->arm_wb_state = true; +} + +/** + * i40evf_force_wb - Issue SW Interrupt so HW does a wb + * @vsi: the VSI we care about + * @q_vector: the vector on which to force writeback + * + **/ +void i40evf_force_wb(struct i40e_vsi *vsi, struct i40e_q_vector *q_vector) +{ + u32 val = I40E_VFINT_DYN_CTLN1_INTENA_MASK | + I40E_VFINT_DYN_CTLN1_ITR_INDX_MASK | /* set noitr */ + I40E_VFINT_DYN_CTLN1_SWINT_TRIG_MASK | + I40E_VFINT_DYN_CTLN1_SW_ITR_INDX_ENA_MASK + /* allow 00 to be written to the index */; + + wr32(&vsi->back->hw, + I40E_VFINT_DYN_CTLN1(q_vector->reg_idx), + val); +} + +static inline bool i40e_container_is_rx(struct i40e_q_vector *q_vector, + struct i40e_ring_container *rc) +{ + return &q_vector->rx == rc; +} + +static inline unsigned int i40e_itr_divisor(struct i40e_q_vector *q_vector) +{ + unsigned int divisor; + + switch (q_vector->adapter->link_speed) { + case I40E_LINK_SPEED_40GB: + divisor = I40E_ITR_ADAPTIVE_MIN_INC * 1024; + break; + case I40E_LINK_SPEED_25GB: + case I40E_LINK_SPEED_20GB: + divisor = I40E_ITR_ADAPTIVE_MIN_INC * 512; + break; + default: + case I40E_LINK_SPEED_10GB: + divisor = I40E_ITR_ADAPTIVE_MIN_INC * 256; + break; + case I40E_LINK_SPEED_1GB: + case I40E_LINK_SPEED_100MB: + divisor = I40E_ITR_ADAPTIVE_MIN_INC * 32; + break; + } + + return divisor; +} + +/** + * i40e_update_itr - update the dynamic ITR value based on statistics + * @q_vector: structure containing interrupt and ring information + * @rc: structure containing ring performance data + * + * Stores a new ITR value based on packets and byte + * counts during the last interrupt. The advantage of per interrupt + * computation is faster updates and more accurate ITR for the current + * traffic pattern. Constants in this function were computed + * based on theoretical maximum wire speed and thresholds were set based + * on testing data as well as attempting to minimize response time + * while increasing bulk throughput. + **/ +static void i40e_update_itr(struct i40e_q_vector *q_vector, + struct i40e_ring_container *rc) +{ + unsigned int avg_wire_size, packets, bytes, itr; + unsigned long next_update = jiffies; + + /* If we don't have any rings just leave ourselves set for maximum + * possible latency so we take ourselves out of the equation. + */ + if (!rc->ring || !ITR_IS_DYNAMIC(rc->ring->itr_setting)) + return; + + /* For Rx we want to push the delay up and default to low latency. + * for Tx we want to pull the delay down and default to high latency. + */ + itr = i40e_container_is_rx(q_vector, rc) ? + I40E_ITR_ADAPTIVE_MIN_USECS | I40E_ITR_ADAPTIVE_LATENCY : + I40E_ITR_ADAPTIVE_MAX_USECS | I40E_ITR_ADAPTIVE_LATENCY; + + /* If we didn't update within up to 1 - 2 jiffies we can assume + * that either packets are coming in so slow there hasn't been + * any work, or that there is so much work that NAPI is dealing + * with interrupt moderation and we don't need to do anything. + */ + if (time_after(next_update, rc->next_update)) + goto clear_counts; + + /* If itr_countdown is set it means we programmed an ITR within + * the last 4 interrupt cycles. This has a side effect of us + * potentially firing an early interrupt. In order to work around + * this we need to throw out any data received for a few + * interrupts following the update. + */ + if (q_vector->itr_countdown) { + itr = rc->target_itr; + goto clear_counts; + } + + packets = rc->total_packets; + bytes = rc->total_bytes; + + if (i40e_container_is_rx(q_vector, rc)) { + /* If Rx there are 1 to 4 packets and bytes are less than + * 9000 assume insufficient data to use bulk rate limiting + * approach unless Tx is already in bulk rate limiting. We + * are likely latency driven. + */ + if (packets && packets < 4 && bytes < 9000 && + (q_vector->tx.target_itr & I40E_ITR_ADAPTIVE_LATENCY)) { + itr = I40E_ITR_ADAPTIVE_LATENCY; + goto adjust_by_size; + } + } else if (packets < 4) { + /* If we have Tx and Rx ITR maxed and Tx ITR is running in + * bulk mode and we are receiving 4 or fewer packets just + * reset the ITR_ADAPTIVE_LATENCY bit for latency mode so + * that the Rx can relax. + */ + if (rc->target_itr == I40E_ITR_ADAPTIVE_MAX_USECS && + (q_vector->rx.target_itr & I40E_ITR_MASK) == + I40E_ITR_ADAPTIVE_MAX_USECS) + goto clear_counts; + } else if (packets > 32) { + /* If we have processed over 32 packets in a single interrupt + * for Tx assume we need to switch over to "bulk" mode. + */ + rc->target_itr &= ~I40E_ITR_ADAPTIVE_LATENCY; + } + + /* We have no packets to actually measure against. This means + * either one of the other queues on this vector is active or + * we are a Tx queue doing TSO with too high of an interrupt rate. + * + * Between 4 and 56 we can assume that our current interrupt delay + * is only slightly too low. As such we should increase it by a small + * fixed amount. + */ + if (packets < 56) { + itr = rc->target_itr + I40E_ITR_ADAPTIVE_MIN_INC; + if ((itr & I40E_ITR_MASK) > I40E_ITR_ADAPTIVE_MAX_USECS) { + itr &= I40E_ITR_ADAPTIVE_LATENCY; + itr += I40E_ITR_ADAPTIVE_MAX_USECS; + } + goto clear_counts; + } + + if (packets <= 256) { + itr = min(q_vector->tx.current_itr, q_vector->rx.current_itr); + itr &= I40E_ITR_MASK; + + /* Between 56 and 112 is our "goldilocks" zone where we are + * working out "just right". Just report that our current + * ITR is good for us. + */ + if (packets <= 112) + goto clear_counts; + + /* If packet count is 128 or greater we are likely looking + * at a slight overrun of the delay we want. Try halving + * our delay to see if that will cut the number of packets + * in half per interrupt. + */ + itr /= 2; + itr &= I40E_ITR_MASK; + if (itr < I40E_ITR_ADAPTIVE_MIN_USECS) + itr = I40E_ITR_ADAPTIVE_MIN_USECS; + + goto clear_counts; + } + + /* The paths below assume we are dealing with a bulk ITR since + * number of packets is greater than 256. We are just going to have + * to compute a value and try to bring the count under control, + * though for smaller packet sizes there isn't much we can do as + * NAPI polling will likely be kicking in sooner rather than later. + */ + itr = I40E_ITR_ADAPTIVE_BULK; + +adjust_by_size: + /* If packet counts are 256 or greater we can assume we have a gross + * overestimation of what the rate should be. Instead of trying to fine + * tune it just use the formula below to try and dial in an exact value + * give the current packet size of the frame. + */ + avg_wire_size = bytes / packets; + + /* The following is a crude approximation of: + * wmem_default / (size + overhead) = desired_pkts_per_int + * rate / bits_per_byte / (size + ethernet overhead) = pkt_rate + * (desired_pkt_rate / pkt_rate) * usecs_per_sec = ITR value + * + * Assuming wmem_default is 212992 and overhead is 640 bytes per + * packet, (256 skb, 64 headroom, 320 shared info), we can reduce the + * formula down to + * + * (170 * (size + 24)) / (size + 640) = ITR + * + * We first do some math on the packet size and then finally bitshift + * by 8 after rounding up. We also have to account for PCIe link speed + * difference as ITR scales based on this. + */ + if (avg_wire_size <= 60) { + /* Start at 250k ints/sec */ + avg_wire_size = 4096; + } else if (avg_wire_size <= 380) { + /* 250K ints/sec to 60K ints/sec */ + avg_wire_size *= 40; + avg_wire_size += 1696; + } else if (avg_wire_size <= 1084) { + /* 60K ints/sec to 36K ints/sec */ + avg_wire_size *= 15; + avg_wire_size += 11452; + } else if (avg_wire_size <= 1980) { + /* 36K ints/sec to 30K ints/sec */ + avg_wire_size *= 5; + avg_wire_size += 22420; + } else { + /* plateau at a limit of 30K ints/sec */ + avg_wire_size = 32256; + } + + /* If we are in low latency mode halve our delay which doubles the + * rate to somewhere between 100K to 16K ints/sec + */ + if (itr & I40E_ITR_ADAPTIVE_LATENCY) + avg_wire_size /= 2; + + /* Resultant value is 256 times larger than it needs to be. This + * gives us room to adjust the value as needed to either increase + * or decrease the value based on link speeds of 10G, 2.5G, 1G, etc. + * + * Use addition as we have already recorded the new latency flag + * for the ITR value. + */ + itr += DIV_ROUND_UP(avg_wire_size, i40e_itr_divisor(q_vector)) * + I40E_ITR_ADAPTIVE_MIN_INC; + + if ((itr & I40E_ITR_MASK) > I40E_ITR_ADAPTIVE_MAX_USECS) { + itr &= I40E_ITR_ADAPTIVE_LATENCY; + itr += I40E_ITR_ADAPTIVE_MAX_USECS; + } + +clear_counts: + /* write back value */ + rc->target_itr = itr; + + /* next update should occur within next jiffy */ + rc->next_update = next_update + 1; + + rc->total_bytes = 0; + rc->total_packets = 0; +} + +/** + * i40evf_setup_tx_descriptors - Allocate the Tx descriptors + * @tx_ring: the tx ring to set up + * + * Return 0 on success, negative on error + **/ +int i40evf_setup_tx_descriptors(struct i40e_ring *tx_ring) +{ + struct device *dev = tx_ring->dev; + int bi_size; + + if (!dev) + return -ENOMEM; + + /* warn if we are about to overwrite the pointer */ + WARN_ON(tx_ring->tx_bi); + bi_size = sizeof(struct i40e_tx_buffer) * tx_ring->count; + tx_ring->tx_bi = kzalloc(bi_size, GFP_KERNEL); + if (!tx_ring->tx_bi) + goto err; + + /* round up to nearest 4K */ + tx_ring->size = tx_ring->count * sizeof(struct i40e_tx_desc); + tx_ring->size = ALIGN(tx_ring->size, 4096); + tx_ring->desc = dma_alloc_coherent(dev, tx_ring->size, + &tx_ring->dma, GFP_KERNEL); + if (!tx_ring->desc) { + dev_info(dev, "Unable to allocate memory for the Tx descriptor ring, size=%d\n", + tx_ring->size); + goto err; + } + + tx_ring->next_to_use = 0; + tx_ring->next_to_clean = 0; + tx_ring->tx_stats.prev_pkt_ctr = -1; + return 0; + +err: + kfree(tx_ring->tx_bi); + tx_ring->tx_bi = NULL; + return -ENOMEM; +} + +/** + * i40evf_clean_rx_ring - Free Rx buffers + * @rx_ring: ring to be cleaned + **/ +void i40evf_clean_rx_ring(struct i40e_ring *rx_ring) +{ + unsigned long bi_size; + u16 i; + + /* ring already cleared, nothing to do */ + if (!rx_ring->rx_bi) + return; + + if (rx_ring->skb) { + dev_kfree_skb(rx_ring->skb); + rx_ring->skb = NULL; + } + + /* Free all the Rx ring sk_buffs */ + for (i = 0; i < rx_ring->count; i++) { + struct i40e_rx_buffer *rx_bi = &rx_ring->rx_bi[i]; + + if (!rx_bi->page) + continue; + + /* Invalidate cache lines that may have been written to by + * device so that we avoid corrupting memory. + */ + dma_sync_single_range_for_cpu(rx_ring->dev, + rx_bi->dma, + rx_bi->page_offset, + rx_ring->rx_buf_len, + DMA_FROM_DEVICE); + + /* free resources associated with mapping */ + dma_unmap_page_attrs(rx_ring->dev, rx_bi->dma, + i40e_rx_pg_size(rx_ring), + DMA_FROM_DEVICE, + I40E_RX_DMA_ATTR); + + __page_frag_cache_drain(rx_bi->page, rx_bi->pagecnt_bias); + + rx_bi->page = NULL; + rx_bi->page_offset = 0; + } + + bi_size = sizeof(struct i40e_rx_buffer) * rx_ring->count; + memset(rx_ring->rx_bi, 0, bi_size); + + /* Zero out the descriptor ring */ + memset(rx_ring->desc, 0, rx_ring->size); + + rx_ring->next_to_alloc = 0; + rx_ring->next_to_clean = 0; + rx_ring->next_to_use = 0; +} + +/** + * i40evf_free_rx_resources - Free Rx resources + * @rx_ring: ring to clean the resources from + * + * Free all receive software resources + **/ +void i40evf_free_rx_resources(struct i40e_ring *rx_ring) +{ + i40evf_clean_rx_ring(rx_ring); + kfree(rx_ring->rx_bi); + rx_ring->rx_bi = NULL; + + if (rx_ring->desc) { + dma_free_coherent(rx_ring->dev, rx_ring->size, + rx_ring->desc, rx_ring->dma); + rx_ring->desc = NULL; + } +} + +/** + * i40evf_setup_rx_descriptors - Allocate Rx descriptors + * @rx_ring: Rx descriptor ring (for a specific queue) to setup + * + * Returns 0 on success, negative on failure + **/ +int i40evf_setup_rx_descriptors(struct i40e_ring *rx_ring) +{ + struct device *dev = rx_ring->dev; + int bi_size; + + /* warn if we are about to overwrite the pointer */ + WARN_ON(rx_ring->rx_bi); + bi_size = sizeof(struct i40e_rx_buffer) * rx_ring->count; + rx_ring->rx_bi = kzalloc(bi_size, GFP_KERNEL); + if (!rx_ring->rx_bi) + goto err; + + u64_stats_init(&rx_ring->syncp); + + /* Round up to nearest 4K */ + rx_ring->size = rx_ring->count * sizeof(union i40e_32byte_rx_desc); + rx_ring->size = ALIGN(rx_ring->size, 4096); + rx_ring->desc = dma_alloc_coherent(dev, rx_ring->size, + &rx_ring->dma, GFP_KERNEL); + + if (!rx_ring->desc) { + dev_info(dev, "Unable to allocate memory for the Rx descriptor ring, size=%d\n", + rx_ring->size); + goto err; + } + + rx_ring->next_to_alloc = 0; + rx_ring->next_to_clean = 0; + rx_ring->next_to_use = 0; + + return 0; +err: + kfree(rx_ring->rx_bi); + rx_ring->rx_bi = NULL; + return -ENOMEM; +} + +/** + * i40e_release_rx_desc - Store the new tail and head values + * @rx_ring: ring to bump + * @val: new head index + **/ +static inline void i40e_release_rx_desc(struct i40e_ring *rx_ring, u32 val) +{ + rx_ring->next_to_use = val; + + /* update next to alloc since we have filled the ring */ + rx_ring->next_to_alloc = val; + + /* Force memory writes to complete before letting h/w + * know there are new descriptors to fetch. (Only + * applicable for weak-ordered memory model archs, + * such as IA-64). + */ + wmb(); + writel(val, rx_ring->tail); +} + +/** + * i40e_rx_offset - Return expected offset into page to access data + * @rx_ring: Ring we are requesting offset of + * + * Returns the offset value for ring into the data buffer. + */ +static inline unsigned int i40e_rx_offset(struct i40e_ring *rx_ring) +{ + return ring_uses_build_skb(rx_ring) ? I40E_SKB_PAD : 0; +} + +/** + * i40e_alloc_mapped_page - recycle or make a new page + * @rx_ring: ring to use + * @bi: rx_buffer struct to modify + * + * Returns true if the page was successfully allocated or + * reused. + **/ +static bool i40e_alloc_mapped_page(struct i40e_ring *rx_ring, + struct i40e_rx_buffer *bi) +{ + struct page *page = bi->page; + dma_addr_t dma; + + /* since we are recycling buffers we should seldom need to alloc */ + if (likely(page)) { + rx_ring->rx_stats.page_reuse_count++; + return true; + } + + /* alloc new page for storage */ + page = dev_alloc_pages(i40e_rx_pg_order(rx_ring)); + if (unlikely(!page)) { + rx_ring->rx_stats.alloc_page_failed++; + return false; + } + + /* map page for use */ + dma = dma_map_page_attrs(rx_ring->dev, page, 0, + i40e_rx_pg_size(rx_ring), + DMA_FROM_DEVICE, + I40E_RX_DMA_ATTR); + + /* if mapping failed free memory back to system since + * there isn't much point in holding memory we can't use + */ + if (dma_mapping_error(rx_ring->dev, dma)) { + __free_pages(page, i40e_rx_pg_order(rx_ring)); + rx_ring->rx_stats.alloc_page_failed++; + return false; + } + + bi->dma = dma; + bi->page = page; + bi->page_offset = i40e_rx_offset(rx_ring); + + /* initialize pagecnt_bias to 1 representing we fully own page */ + bi->pagecnt_bias = 1; + + return true; +} + +/** + * i40e_receive_skb - Send a completed packet up the stack + * @rx_ring: rx ring in play + * @skb: packet to send up + * @vlan_tag: vlan tag for packet + **/ +static void i40e_receive_skb(struct i40e_ring *rx_ring, + struct sk_buff *skb, u16 vlan_tag) +{ + struct i40e_q_vector *q_vector = rx_ring->q_vector; + + if ((rx_ring->netdev->features & NETIF_F_HW_VLAN_CTAG_RX) && + (vlan_tag & VLAN_VID_MASK)) + __vlan_hwaccel_put_tag(skb, htons(ETH_P_8021Q), vlan_tag); + + napi_gro_receive(&q_vector->napi, skb); +} + +/** + * i40evf_alloc_rx_buffers - Replace used receive buffers + * @rx_ring: ring to place buffers on + * @cleaned_count: number of buffers to replace + * + * Returns false if all allocations were successful, true if any fail + **/ +bool i40evf_alloc_rx_buffers(struct i40e_ring *rx_ring, u16 cleaned_count) +{ + u16 ntu = rx_ring->next_to_use; + union i40e_rx_desc *rx_desc; + struct i40e_rx_buffer *bi; + + /* do nothing if no valid netdev defined */ + if (!rx_ring->netdev || !cleaned_count) + return false; + + rx_desc = I40E_RX_DESC(rx_ring, ntu); + bi = &rx_ring->rx_bi[ntu]; + + do { + if (!i40e_alloc_mapped_page(rx_ring, bi)) + goto no_buffers; + + /* sync the buffer for use by the device */ + dma_sync_single_range_for_device(rx_ring->dev, bi->dma, + bi->page_offset, + rx_ring->rx_buf_len, + DMA_FROM_DEVICE); + + /* Refresh the desc even if buffer_addrs didn't change + * because each write-back erases this info. + */ + rx_desc->read.pkt_addr = cpu_to_le64(bi->dma + bi->page_offset); + + rx_desc++; + bi++; + ntu++; + if (unlikely(ntu == rx_ring->count)) { + rx_desc = I40E_RX_DESC(rx_ring, 0); + bi = rx_ring->rx_bi; + ntu = 0; + } + + /* clear the status bits for the next_to_use descriptor */ + rx_desc->wb.qword1.status_error_len = 0; + + cleaned_count--; + } while (cleaned_count); + + if (rx_ring->next_to_use != ntu) + i40e_release_rx_desc(rx_ring, ntu); + + return false; + +no_buffers: + if (rx_ring->next_to_use != ntu) + i40e_release_rx_desc(rx_ring, ntu); + + /* make sure to come back via polling to try again after + * allocation failure + */ + return true; +} + +/** + * i40e_rx_checksum - Indicate in skb if hw indicated a good cksum + * @vsi: the VSI we care about + * @skb: skb currently being received and modified + * @rx_desc: the receive descriptor + **/ +static inline void i40e_rx_checksum(struct i40e_vsi *vsi, + struct sk_buff *skb, + union i40e_rx_desc *rx_desc) +{ + struct i40e_rx_ptype_decoded decoded; + u32 rx_error, rx_status; + bool ipv4, ipv6; + u8 ptype; + u64 qword; + + qword = le64_to_cpu(rx_desc->wb.qword1.status_error_len); + ptype = (qword & I40E_RXD_QW1_PTYPE_MASK) >> I40E_RXD_QW1_PTYPE_SHIFT; + rx_error = (qword & I40E_RXD_QW1_ERROR_MASK) >> + I40E_RXD_QW1_ERROR_SHIFT; + rx_status = (qword & I40E_RXD_QW1_STATUS_MASK) >> + I40E_RXD_QW1_STATUS_SHIFT; + decoded = decode_rx_desc_ptype(ptype); + + skb->ip_summed = CHECKSUM_NONE; + + skb_checksum_none_assert(skb); + + /* Rx csum enabled and ip headers found? */ + if (!(vsi->netdev->features & NETIF_F_RXCSUM)) + return; + + /* did the hardware decode the packet and checksum? */ + if (!(rx_status & BIT(I40E_RX_DESC_STATUS_L3L4P_SHIFT))) + return; + + /* both known and outer_ip must be set for the below code to work */ + if (!(decoded.known && decoded.outer_ip)) + return; + + ipv4 = (decoded.outer_ip == I40E_RX_PTYPE_OUTER_IP) && + (decoded.outer_ip_ver == I40E_RX_PTYPE_OUTER_IPV4); + ipv6 = (decoded.outer_ip == I40E_RX_PTYPE_OUTER_IP) && + (decoded.outer_ip_ver == I40E_RX_PTYPE_OUTER_IPV6); + + if (ipv4 && + (rx_error & (BIT(I40E_RX_DESC_ERROR_IPE_SHIFT) | + BIT(I40E_RX_DESC_ERROR_EIPE_SHIFT)))) + goto checksum_fail; + + /* likely incorrect csum if alternate IP extension headers found */ + if (ipv6 && + rx_status & BIT(I40E_RX_DESC_STATUS_IPV6EXADD_SHIFT)) + /* don't increment checksum err here, non-fatal err */ + return; + + /* there was some L4 error, count error and punt packet to the stack */ + if (rx_error & BIT(I40E_RX_DESC_ERROR_L4E_SHIFT)) + goto checksum_fail; + + /* handle packets that were not able to be checksummed due + * to arrival speed, in this case the stack can compute + * the csum. + */ + if (rx_error & BIT(I40E_RX_DESC_ERROR_PPRS_SHIFT)) + return; + + /* Only report checksum unnecessary for TCP, UDP, or SCTP */ + switch (decoded.inner_prot) { + case I40E_RX_PTYPE_INNER_PROT_TCP: + case I40E_RX_PTYPE_INNER_PROT_UDP: + case I40E_RX_PTYPE_INNER_PROT_SCTP: + skb->ip_summed = CHECKSUM_UNNECESSARY; + /* fall though */ + default: + break; + } + + return; + +checksum_fail: + vsi->back->hw_csum_rx_error++; +} + +/** + * i40e_ptype_to_htype - get a hash type + * @ptype: the ptype value from the descriptor + * + * Returns a hash type to be used by skb_set_hash + **/ +static inline int i40e_ptype_to_htype(u8 ptype) +{ + struct i40e_rx_ptype_decoded decoded = decode_rx_desc_ptype(ptype); + + if (!decoded.known) + return PKT_HASH_TYPE_NONE; + + if (decoded.outer_ip == I40E_RX_PTYPE_OUTER_IP && + decoded.payload_layer == I40E_RX_PTYPE_PAYLOAD_LAYER_PAY4) + return PKT_HASH_TYPE_L4; + else if (decoded.outer_ip == I40E_RX_PTYPE_OUTER_IP && + decoded.payload_layer == I40E_RX_PTYPE_PAYLOAD_LAYER_PAY3) + return PKT_HASH_TYPE_L3; + else + return PKT_HASH_TYPE_L2; +} + +/** + * i40e_rx_hash - set the hash value in the skb + * @ring: descriptor ring + * @rx_desc: specific descriptor + * @skb: skb currently being received and modified + * @rx_ptype: Rx packet type + **/ +static inline void i40e_rx_hash(struct i40e_ring *ring, + union i40e_rx_desc *rx_desc, + struct sk_buff *skb, + u8 rx_ptype) +{ + u32 hash; + const __le64 rss_mask = + cpu_to_le64((u64)I40E_RX_DESC_FLTSTAT_RSS_HASH << + I40E_RX_DESC_STATUS_FLTSTAT_SHIFT); + + if (ring->netdev->features & NETIF_F_RXHASH) + return; + + if ((rx_desc->wb.qword1.status_error_len & rss_mask) == rss_mask) { + hash = le32_to_cpu(rx_desc->wb.qword0.hi_dword.rss); + skb_set_hash(skb, hash, i40e_ptype_to_htype(rx_ptype)); + } +} + +/** + * i40evf_process_skb_fields - Populate skb header fields from Rx descriptor + * @rx_ring: rx descriptor ring packet is being transacted on + * @rx_desc: pointer to the EOP Rx descriptor + * @skb: pointer to current skb being populated + * @rx_ptype: the packet type decoded by hardware + * + * This function checks the ring, descriptor, and packet information in + * order to populate the hash, checksum, VLAN, protocol, and + * other fields within the skb. + **/ +static inline +void i40evf_process_skb_fields(struct i40e_ring *rx_ring, + union i40e_rx_desc *rx_desc, struct sk_buff *skb, + u8 rx_ptype) +{ + i40e_rx_hash(rx_ring, rx_desc, skb, rx_ptype); + + i40e_rx_checksum(rx_ring->vsi, skb, rx_desc); + + skb_record_rx_queue(skb, rx_ring->queue_index); + + /* modifies the skb - consumes the enet header */ + skb->protocol = eth_type_trans(skb, rx_ring->netdev); +} + +/** + * i40e_cleanup_headers - Correct empty headers + * @rx_ring: rx descriptor ring packet is being transacted on + * @skb: pointer to current skb being fixed + * + * Also address the case where we are pulling data in on pages only + * and as such no data is present in the skb header. + * + * In addition if skb is not at least 60 bytes we need to pad it so that + * it is large enough to qualify as a valid Ethernet frame. + * + * Returns true if an error was encountered and skb was freed. + **/ +static bool i40e_cleanup_headers(struct i40e_ring *rx_ring, struct sk_buff *skb) +{ + /* if eth_skb_pad returns an error the skb was freed */ + if (eth_skb_pad(skb)) + return true; + + return false; +} + +/** + * i40e_reuse_rx_page - page flip buffer and store it back on the ring + * @rx_ring: rx descriptor ring to store buffers on + * @old_buff: donor buffer to have page reused + * + * Synchronizes page for reuse by the adapter + **/ +static void i40e_reuse_rx_page(struct i40e_ring *rx_ring, + struct i40e_rx_buffer *old_buff) +{ + struct i40e_rx_buffer *new_buff; + u16 nta = rx_ring->next_to_alloc; + + new_buff = &rx_ring->rx_bi[nta]; + + /* update, and store next to alloc */ + nta++; + rx_ring->next_to_alloc = (nta < rx_ring->count) ? nta : 0; + + /* transfer page from old buffer to new buffer */ + new_buff->dma = old_buff->dma; + new_buff->page = old_buff->page; + new_buff->page_offset = old_buff->page_offset; + new_buff->pagecnt_bias = old_buff->pagecnt_bias; +} + +/** + * i40e_page_is_reusable - check if any reuse is possible + * @page: page struct to check + * + * A page is not reusable if it was allocated under low memory + * conditions, or it's not in the same NUMA node as this CPU. + */ +static inline bool i40e_page_is_reusable(struct page *page) +{ + return (page_to_nid(page) == numa_mem_id()) && + !page_is_pfmemalloc(page); +} + +/** + * i40e_can_reuse_rx_page - Determine if this page can be reused by + * the adapter for another receive + * + * @rx_buffer: buffer containing the page + * + * If page is reusable, rx_buffer->page_offset is adjusted to point to + * an unused region in the page. + * + * For small pages, @truesize will be a constant value, half the size + * of the memory at page. We'll attempt to alternate between high and + * low halves of the page, with one half ready for use by the hardware + * and the other half being consumed by the stack. We use the page + * ref count to determine whether the stack has finished consuming the + * portion of this page that was passed up with a previous packet. If + * the page ref count is >1, we'll assume the "other" half page is + * still busy, and this page cannot be reused. + * + * For larger pages, @truesize will be the actual space used by the + * received packet (adjusted upward to an even multiple of the cache + * line size). This will advance through the page by the amount + * actually consumed by the received packets while there is still + * space for a buffer. Each region of larger pages will be used at + * most once, after which the page will not be reused. + * + * In either case, if the page is reusable its refcount is increased. + **/ +static bool i40e_can_reuse_rx_page(struct i40e_rx_buffer *rx_buffer) +{ + unsigned int pagecnt_bias = rx_buffer->pagecnt_bias; + struct page *page = rx_buffer->page; + + /* Is any reuse possible? */ + if (unlikely(!i40e_page_is_reusable(page))) + return false; + +#if (PAGE_SIZE < 8192) + /* if we are only owner of page we can reuse it */ + if (unlikely((page_count(page) - pagecnt_bias) > 1)) + return false; +#else +#define I40E_LAST_OFFSET \ + (SKB_WITH_OVERHEAD(PAGE_SIZE) - I40E_RXBUFFER_2048) + if (rx_buffer->page_offset > I40E_LAST_OFFSET) + return false; +#endif + + /* If we have drained the page fragment pool we need to update + * the pagecnt_bias and page count so that we fully restock the + * number of references the driver holds. + */ + if (unlikely(!pagecnt_bias)) { + page_ref_add(page, USHRT_MAX); + rx_buffer->pagecnt_bias = USHRT_MAX; + } + + return true; +} + +/** + * i40e_add_rx_frag - Add contents of Rx buffer to sk_buff + * @rx_ring: rx descriptor ring to transact packets on + * @rx_buffer: buffer containing page to add + * @skb: sk_buff to place the data into + * @size: packet length from rx_desc + * + * This function will add the data contained in rx_buffer->page to the skb. + * It will just attach the page as a frag to the skb. + * + * The function will then update the page offset. + **/ +static void i40e_add_rx_frag(struct i40e_ring *rx_ring, + struct i40e_rx_buffer *rx_buffer, + struct sk_buff *skb, + unsigned int size) +{ +#if (PAGE_SIZE < 8192) + unsigned int truesize = i40e_rx_pg_size(rx_ring) / 2; +#else + unsigned int truesize = SKB_DATA_ALIGN(size + i40e_rx_offset(rx_ring)); +#endif + + skb_add_rx_frag(skb, skb_shinfo(skb)->nr_frags, rx_buffer->page, + rx_buffer->page_offset, size, truesize); + + /* page is being used so we must update the page offset */ +#if (PAGE_SIZE < 8192) + rx_buffer->page_offset ^= truesize; +#else + rx_buffer->page_offset += truesize; +#endif +} + +/** + * i40e_get_rx_buffer - Fetch Rx buffer and synchronize data for use + * @rx_ring: rx descriptor ring to transact packets on + * @size: size of buffer to add to skb + * + * This function will pull an Rx buffer from the ring and synchronize it + * for use by the CPU. + */ +static struct i40e_rx_buffer *i40e_get_rx_buffer(struct i40e_ring *rx_ring, + const unsigned int size) +{ + struct i40e_rx_buffer *rx_buffer; + + rx_buffer = &rx_ring->rx_bi[rx_ring->next_to_clean]; + prefetchw(rx_buffer->page); + + /* we are reusing so sync this buffer for CPU use */ + dma_sync_single_range_for_cpu(rx_ring->dev, + rx_buffer->dma, + rx_buffer->page_offset, + size, + DMA_FROM_DEVICE); + + /* We have pulled a buffer for use, so decrement pagecnt_bias */ + rx_buffer->pagecnt_bias--; + + return rx_buffer; +} + +/** + * i40e_construct_skb - Allocate skb and populate it + * @rx_ring: rx descriptor ring to transact packets on + * @rx_buffer: rx buffer to pull data from + * @size: size of buffer to add to skb + * + * This function allocates an skb. It then populates it with the page + * data from the current receive descriptor, taking care to set up the + * skb correctly. + */ +static struct sk_buff *i40e_construct_skb(struct i40e_ring *rx_ring, + struct i40e_rx_buffer *rx_buffer, + unsigned int size) +{ + void *va; +#if (PAGE_SIZE < 8192) + unsigned int truesize = i40e_rx_pg_size(rx_ring) / 2; +#else + unsigned int truesize = SKB_DATA_ALIGN(size); +#endif + unsigned int headlen; + struct sk_buff *skb; + + /* prefetch first cache line of first page */ + va = page_address(rx_buffer->page) + rx_buffer->page_offset; + prefetch(va); +#if L1_CACHE_BYTES < 128 + prefetch(va + L1_CACHE_BYTES); +#endif + + /* allocate a skb to store the frags */ + skb = __napi_alloc_skb(&rx_ring->q_vector->napi, + I40E_RX_HDR_SIZE, + GFP_ATOMIC | __GFP_NOWARN); + if (unlikely(!skb)) + return NULL; + + /* Determine available headroom for copy */ + headlen = size; + if (headlen > I40E_RX_HDR_SIZE) + headlen = eth_get_headlen(va, I40E_RX_HDR_SIZE); + + /* align pull length to size of long to optimize memcpy performance */ + memcpy(__skb_put(skb, headlen), va, ALIGN(headlen, sizeof(long))); + + /* update all of the pointers */ + size -= headlen; + if (size) { + skb_add_rx_frag(skb, 0, rx_buffer->page, + rx_buffer->page_offset + headlen, + size, truesize); + + /* buffer is used by skb, update page_offset */ +#if (PAGE_SIZE < 8192) + rx_buffer->page_offset ^= truesize; +#else + rx_buffer->page_offset += truesize; +#endif + } else { + /* buffer is unused, reset bias back to rx_buffer */ + rx_buffer->pagecnt_bias++; + } + + return skb; +} + +/** + * i40e_build_skb - Build skb around an existing buffer + * @rx_ring: Rx descriptor ring to transact packets on + * @rx_buffer: Rx buffer to pull data from + * @size: size of buffer to add to skb + * + * This function builds an skb around an existing Rx buffer, taking care + * to set up the skb correctly and avoid any memcpy overhead. + */ +static struct sk_buff *i40e_build_skb(struct i40e_ring *rx_ring, + struct i40e_rx_buffer *rx_buffer, + unsigned int size) +{ + void *va; +#if (PAGE_SIZE < 8192) + unsigned int truesize = i40e_rx_pg_size(rx_ring) / 2; +#else + unsigned int truesize = SKB_DATA_ALIGN(sizeof(struct skb_shared_info)) + + SKB_DATA_ALIGN(I40E_SKB_PAD + size); +#endif + struct sk_buff *skb; + + /* prefetch first cache line of first page */ + va = page_address(rx_buffer->page) + rx_buffer->page_offset; + prefetch(va); +#if L1_CACHE_BYTES < 128 + prefetch(va + L1_CACHE_BYTES); +#endif + /* build an skb around the page buffer */ + skb = build_skb(va - I40E_SKB_PAD, truesize); + if (unlikely(!skb)) + return NULL; + + /* update pointers within the skb to store the data */ + skb_reserve(skb, I40E_SKB_PAD); + __skb_put(skb, size); + + /* buffer is used by skb, update page_offset */ +#if (PAGE_SIZE < 8192) + rx_buffer->page_offset ^= truesize; +#else + rx_buffer->page_offset += truesize; +#endif + + return skb; +} + +/** + * i40e_put_rx_buffer - Clean up used buffer and either recycle or free + * @rx_ring: rx descriptor ring to transact packets on + * @rx_buffer: rx buffer to pull data from + * + * This function will clean up the contents of the rx_buffer. It will + * either recycle the buffer or unmap it and free the associated resources. + */ +static void i40e_put_rx_buffer(struct i40e_ring *rx_ring, + struct i40e_rx_buffer *rx_buffer) +{ + if (i40e_can_reuse_rx_page(rx_buffer)) { + /* hand second half of page back to the ring */ + i40e_reuse_rx_page(rx_ring, rx_buffer); + rx_ring->rx_stats.page_reuse_count++; + } else { + /* we are not reusing the buffer so unmap it */ + dma_unmap_page_attrs(rx_ring->dev, rx_buffer->dma, + i40e_rx_pg_size(rx_ring), + DMA_FROM_DEVICE, I40E_RX_DMA_ATTR); + __page_frag_cache_drain(rx_buffer->page, + rx_buffer->pagecnt_bias); + } + + /* clear contents of buffer_info */ + rx_buffer->page = NULL; +} + +/** + * i40e_is_non_eop - process handling of non-EOP buffers + * @rx_ring: Rx ring being processed + * @rx_desc: Rx descriptor for current buffer + * @skb: Current socket buffer containing buffer in progress + * + * This function updates next to clean. If the buffer is an EOP buffer + * this function exits returning false, otherwise it will place the + * sk_buff in the next buffer to be chained and return true indicating + * that this is in fact a non-EOP buffer. + **/ +static bool i40e_is_non_eop(struct i40e_ring *rx_ring, + union i40e_rx_desc *rx_desc, + struct sk_buff *skb) +{ + u32 ntc = rx_ring->next_to_clean + 1; + + /* fetch, update, and store next to clean */ + ntc = (ntc < rx_ring->count) ? ntc : 0; + rx_ring->next_to_clean = ntc; + + prefetch(I40E_RX_DESC(rx_ring, ntc)); + + /* if we are the last buffer then there is nothing else to do */ +#define I40E_RXD_EOF BIT(I40E_RX_DESC_STATUS_EOF_SHIFT) + if (likely(i40e_test_staterr(rx_desc, I40E_RXD_EOF))) + return false; + + rx_ring->rx_stats.non_eop_descs++; + + return true; +} + +/** + * i40e_clean_rx_irq - Clean completed descriptors from Rx ring - bounce buf + * @rx_ring: rx descriptor ring to transact packets on + * @budget: Total limit on number of packets to process + * + * This function provides a "bounce buffer" approach to Rx interrupt + * processing. The advantage to this is that on systems that have + * expensive overhead for IOMMU access this provides a means of avoiding + * it by maintaining the mapping of the page to the system. + * + * Returns amount of work completed + **/ +static int i40e_clean_rx_irq(struct i40e_ring *rx_ring, int budget) +{ + unsigned int total_rx_bytes = 0, total_rx_packets = 0; + struct sk_buff *skb = rx_ring->skb; + u16 cleaned_count = I40E_DESC_UNUSED(rx_ring); + bool failure = false; + + while (likely(total_rx_packets < (unsigned int)budget)) { + struct i40e_rx_buffer *rx_buffer; + union i40e_rx_desc *rx_desc; + unsigned int size; + u16 vlan_tag; + u8 rx_ptype; + u64 qword; + + /* return some buffers to hardware, one at a time is too slow */ + if (cleaned_count >= I40E_RX_BUFFER_WRITE) { + failure = failure || + i40evf_alloc_rx_buffers(rx_ring, cleaned_count); + cleaned_count = 0; + } + + rx_desc = I40E_RX_DESC(rx_ring, rx_ring->next_to_clean); + + /* status_error_len will always be zero for unused descriptors + * because it's cleared in cleanup, and overlaps with hdr_addr + * which is always zero because packet split isn't used, if the + * hardware wrote DD then the length will be non-zero + */ + qword = le64_to_cpu(rx_desc->wb.qword1.status_error_len); + + /* This memory barrier is needed to keep us from reading + * any other fields out of the rx_desc until we have + * verified the descriptor has been written back. + */ + dma_rmb(); + + size = (qword & I40E_RXD_QW1_LENGTH_PBUF_MASK) >> + I40E_RXD_QW1_LENGTH_PBUF_SHIFT; + if (!size) + break; + + i40e_trace(clean_rx_irq, rx_ring, rx_desc, skb); + rx_buffer = i40e_get_rx_buffer(rx_ring, size); + + /* retrieve a buffer from the ring */ + if (skb) + i40e_add_rx_frag(rx_ring, rx_buffer, skb, size); + else if (ring_uses_build_skb(rx_ring)) + skb = i40e_build_skb(rx_ring, rx_buffer, size); + else + skb = i40e_construct_skb(rx_ring, rx_buffer, size); + + /* exit if we failed to retrieve a buffer */ + if (!skb) { + rx_ring->rx_stats.alloc_buff_failed++; + rx_buffer->pagecnt_bias++; + break; + } + + i40e_put_rx_buffer(rx_ring, rx_buffer); + cleaned_count++; + + if (i40e_is_non_eop(rx_ring, rx_desc, skb)) + continue; + + /* ERR_MASK will only have valid bits if EOP set, and + * what we are doing here is actually checking + * I40E_RX_DESC_ERROR_RXE_SHIFT, since it is the zeroth bit in + * the error field + */ + if (unlikely(i40e_test_staterr(rx_desc, BIT(I40E_RXD_QW1_ERROR_SHIFT)))) { + dev_kfree_skb_any(skb); + skb = NULL; + continue; + } + + if (i40e_cleanup_headers(rx_ring, skb)) { + skb = NULL; + continue; + } + + /* probably a little skewed due to removing CRC */ + total_rx_bytes += skb->len; + + qword = le64_to_cpu(rx_desc->wb.qword1.status_error_len); + rx_ptype = (qword & I40E_RXD_QW1_PTYPE_MASK) >> + I40E_RXD_QW1_PTYPE_SHIFT; + + /* populate checksum, VLAN, and protocol */ + i40evf_process_skb_fields(rx_ring, rx_desc, skb, rx_ptype); + + + vlan_tag = (qword & BIT(I40E_RX_DESC_STATUS_L2TAG1P_SHIFT)) ? + le16_to_cpu(rx_desc->wb.qword0.lo_dword.l2tag1) : 0; + + i40e_trace(clean_rx_irq_rx, rx_ring, rx_desc, skb); + i40e_receive_skb(rx_ring, skb, vlan_tag); + skb = NULL; + + /* update budget accounting */ + total_rx_packets++; + } + + rx_ring->skb = skb; + + u64_stats_update_begin(&rx_ring->syncp); + rx_ring->stats.packets += total_rx_packets; + rx_ring->stats.bytes += total_rx_bytes; + u64_stats_update_end(&rx_ring->syncp); + rx_ring->q_vector->rx.total_packets += total_rx_packets; + rx_ring->q_vector->rx.total_bytes += total_rx_bytes; + + /* guarantee a trip back through this routine if there was a failure */ + return failure ? budget : (int)total_rx_packets; +} + +static inline u32 i40e_buildreg_itr(const int type, u16 itr) +{ + u32 val; + + /* We don't bother with setting the CLEARPBA bit as the data sheet + * points out doing so is "meaningless since it was already + * auto-cleared". The auto-clearing happens when the interrupt is + * asserted. + * + * Hardware errata 28 for also indicates that writing to a + * xxINT_DYN_CTLx CSR with INTENA_MSK (bit 31) set to 0 will clear + * an event in the PBA anyway so we need to rely on the automask + * to hold pending events for us until the interrupt is re-enabled + * + * The itr value is reported in microseconds, and the register + * value is recorded in 2 microsecond units. For this reason we + * only need to shift by the interval shift - 1 instead of the + * full value. + */ + itr &= I40E_ITR_MASK; + + val = I40E_VFINT_DYN_CTLN1_INTENA_MASK | + (type << I40E_VFINT_DYN_CTLN1_ITR_INDX_SHIFT) | + (itr << (I40E_VFINT_DYN_CTLN1_INTERVAL_SHIFT - 1)); + + return val; +} + +/* a small macro to shorten up some long lines */ +#define INTREG I40E_VFINT_DYN_CTLN1 + +/* The act of updating the ITR will cause it to immediately trigger. In order + * to prevent this from throwing off adaptive update statistics we defer the + * update so that it can only happen so often. So after either Tx or Rx are + * updated we make the adaptive scheme wait until either the ITR completely + * expires via the next_update expiration or we have been through at least + * 3 interrupts. + */ +#define ITR_COUNTDOWN_START 3 + +/** + * i40e_update_enable_itr - Update itr and re-enable MSIX interrupt + * @vsi: the VSI we care about + * @q_vector: q_vector for which itr is being updated and interrupt enabled + * + **/ +static inline void i40e_update_enable_itr(struct i40e_vsi *vsi, + struct i40e_q_vector *q_vector) +{ + struct i40e_hw *hw = &vsi->back->hw; + u32 intval; + + /* These will do nothing if dynamic updates are not enabled */ + i40e_update_itr(q_vector, &q_vector->tx); + i40e_update_itr(q_vector, &q_vector->rx); + + /* This block of logic allows us to get away with only updating + * one ITR value with each interrupt. The idea is to perform a + * pseudo-lazy update with the following criteria. + * + * 1. Rx is given higher priority than Tx if both are in same state + * 2. If we must reduce an ITR that is given highest priority. + * 3. We then give priority to increasing ITR based on amount. + */ + if (q_vector->rx.target_itr < q_vector->rx.current_itr) { + /* Rx ITR needs to be reduced, this is highest priority */ + intval = i40e_buildreg_itr(I40E_RX_ITR, + q_vector->rx.target_itr); + q_vector->rx.current_itr = q_vector->rx.target_itr; + q_vector->itr_countdown = ITR_COUNTDOWN_START; + } else if ((q_vector->tx.target_itr < q_vector->tx.current_itr) || + ((q_vector->rx.target_itr - q_vector->rx.current_itr) < + (q_vector->tx.target_itr - q_vector->tx.current_itr))) { + /* Tx ITR needs to be reduced, this is second priority + * Tx ITR needs to be increased more than Rx, fourth priority + */ + intval = i40e_buildreg_itr(I40E_TX_ITR, + q_vector->tx.target_itr); + q_vector->tx.current_itr = q_vector->tx.target_itr; + q_vector->itr_countdown = ITR_COUNTDOWN_START; + } else if (q_vector->rx.current_itr != q_vector->rx.target_itr) { + /* Rx ITR needs to be increased, third priority */ + intval = i40e_buildreg_itr(I40E_RX_ITR, + q_vector->rx.target_itr); + q_vector->rx.current_itr = q_vector->rx.target_itr; + q_vector->itr_countdown = ITR_COUNTDOWN_START; + } else { + /* No ITR update, lowest priority */ + intval = i40e_buildreg_itr(I40E_ITR_NONE, 0); + if (q_vector->itr_countdown) + q_vector->itr_countdown--; + } + + if (!test_bit(__I40E_VSI_DOWN, vsi->state)) + wr32(hw, INTREG(q_vector->reg_idx), intval); +} + +/** + * i40evf_napi_poll - NAPI polling Rx/Tx cleanup routine + * @napi: napi struct with our devices info in it + * @budget: amount of work driver is allowed to do this pass, in packets + * + * This function will clean all queues associated with a q_vector. + * + * Returns the amount of work done + **/ +int i40evf_napi_poll(struct napi_struct *napi, int budget) +{ + struct i40e_q_vector *q_vector = + container_of(napi, struct i40e_q_vector, napi); + struct i40e_vsi *vsi = q_vector->vsi; + struct i40e_ring *ring; + bool clean_complete = true; + bool arm_wb = false; + int budget_per_ring; + int work_done = 0; + + if (test_bit(__I40E_VSI_DOWN, vsi->state)) { + napi_complete(napi); + return 0; + } + + /* Since the actual Tx work is minimal, we can give the Tx a larger + * budget and be more aggressive about cleaning up the Tx descriptors. + */ + i40e_for_each_ring(ring, q_vector->tx) { + if (!i40e_clean_tx_irq(vsi, ring, budget)) { + clean_complete = false; + continue; + } + arm_wb |= ring->arm_wb; + ring->arm_wb = false; + } + + /* Handle case where we are called by netpoll with a budget of 0 */ + if (budget <= 0) + goto tx_only; + + /* We attempt to distribute budget to each Rx queue fairly, but don't + * allow the budget to go below 1 because that would exit polling early. + */ + budget_per_ring = max(budget/q_vector->num_ringpairs, 1); + + i40e_for_each_ring(ring, q_vector->rx) { + int cleaned = i40e_clean_rx_irq(ring, budget_per_ring); + + work_done += cleaned; + /* if we clean as many as budgeted, we must not be done */ + if (cleaned >= budget_per_ring) + clean_complete = false; + } + + /* If work not completed, return budget and polling will return */ + if (!clean_complete) { + int cpu_id = smp_processor_id(); + + /* It is possible that the interrupt affinity has changed but, + * if the cpu is pegged at 100%, polling will never exit while + * traffic continues and the interrupt will be stuck on this + * cpu. We check to make sure affinity is correct before we + * continue to poll, otherwise we must stop polling so the + * interrupt can move to the correct cpu. + */ + if (!cpumask_test_cpu(cpu_id, &q_vector->affinity_mask)) { + /* Tell napi that we are done polling */ + napi_complete_done(napi, work_done); + + /* Force an interrupt */ + i40evf_force_wb(vsi, q_vector); + + /* Return budget-1 so that polling stops */ + return budget - 1; + } +tx_only: + if (arm_wb) { + q_vector->tx.ring[0].tx_stats.tx_force_wb++; + i40e_enable_wb_on_itr(vsi, q_vector); + } + return budget; + } + + if (vsi->back->flags & I40E_TXR_FLAGS_WB_ON_ITR) + q_vector->arm_wb_state = false; + + /* Work is done so exit the polling mode and re-enable the interrupt */ + napi_complete_done(napi, work_done); + + i40e_update_enable_itr(vsi, q_vector); + + return min(work_done, budget - 1); +} + +/** + * i40evf_tx_prepare_vlan_flags - prepare generic TX VLAN tagging flags for HW + * @skb: send buffer + * @tx_ring: ring to send buffer on + * @flags: the tx flags to be set + * + * Checks the skb and set up correspondingly several generic transmit flags + * related to VLAN tagging for the HW, such as VLAN, DCB, etc. + * + * Returns error code indicate the frame should be dropped upon error and the + * otherwise returns 0 to indicate the flags has been set properly. + **/ +static inline int i40evf_tx_prepare_vlan_flags(struct sk_buff *skb, + struct i40e_ring *tx_ring, + u32 *flags) +{ + __be16 protocol = skb->protocol; + u32 tx_flags = 0; + + if (protocol == htons(ETH_P_8021Q) && + !(tx_ring->netdev->features & NETIF_F_HW_VLAN_CTAG_TX)) { + /* When HW VLAN acceleration is turned off by the user the + * stack sets the protocol to 8021q so that the driver + * can take any steps required to support the SW only + * VLAN handling. In our case the driver doesn't need + * to take any further steps so just set the protocol + * to the encapsulated ethertype. + */ + skb->protocol = vlan_get_protocol(skb); + goto out; + } + + /* if we have a HW VLAN tag being added, default to the HW one */ + if (skb_vlan_tag_present(skb)) { + tx_flags |= skb_vlan_tag_get(skb) << I40E_TX_FLAGS_VLAN_SHIFT; + tx_flags |= I40E_TX_FLAGS_HW_VLAN; + /* else if it is a SW VLAN, check the next protocol and store the tag */ + } else if (protocol == htons(ETH_P_8021Q)) { + struct vlan_hdr *vhdr, _vhdr; + + vhdr = skb_header_pointer(skb, ETH_HLEN, sizeof(_vhdr), &_vhdr); + if (!vhdr) + return -EINVAL; + + protocol = vhdr->h_vlan_encapsulated_proto; + tx_flags |= ntohs(vhdr->h_vlan_TCI) << I40E_TX_FLAGS_VLAN_SHIFT; + tx_flags |= I40E_TX_FLAGS_SW_VLAN; + } + +out: + *flags = tx_flags; + return 0; +} + +/** + * i40e_tso - set up the tso context descriptor + * @first: pointer to first Tx buffer for xmit + * @hdr_len: ptr to the size of the packet header + * @cd_type_cmd_tso_mss: Quad Word 1 + * + * Returns 0 if no TSO can happen, 1 if tso is going, or error + **/ +static int i40e_tso(struct i40e_tx_buffer *first, u8 *hdr_len, + u64 *cd_type_cmd_tso_mss) +{ + struct sk_buff *skb = first->skb; + u64 cd_cmd, cd_tso_len, cd_mss; + union { + struct iphdr *v4; + struct ipv6hdr *v6; + unsigned char *hdr; + } ip; + union { + struct tcphdr *tcp; + struct udphdr *udp; + unsigned char *hdr; + } l4; + u32 paylen, l4_offset; + u16 gso_segs, gso_size; + int err; + + if (skb->ip_summed != CHECKSUM_PARTIAL) + return 0; + + if (!skb_is_gso(skb)) + return 0; + + err = skb_cow_head(skb, 0); + if (err < 0) + return err; + + ip.hdr = skb_network_header(skb); + l4.hdr = skb_transport_header(skb); + + /* initialize outer IP header fields */ + if (ip.v4->version == 4) { + ip.v4->tot_len = 0; + ip.v4->check = 0; + } else { + ip.v6->payload_len = 0; + } + + if (skb_shinfo(skb)->gso_type & (SKB_GSO_GRE | + SKB_GSO_GRE_CSUM | + SKB_GSO_IPXIP4 | + SKB_GSO_IPXIP6 | + SKB_GSO_UDP_TUNNEL | + SKB_GSO_UDP_TUNNEL_CSUM)) { + if (!(skb_shinfo(skb)->gso_type & SKB_GSO_PARTIAL) && + (skb_shinfo(skb)->gso_type & SKB_GSO_UDP_TUNNEL_CSUM)) { + l4.udp->len = 0; + + /* determine offset of outer transport header */ + l4_offset = l4.hdr - skb->data; + + /* remove payload length from outer checksum */ + paylen = skb->len - l4_offset; + csum_replace_by_diff(&l4.udp->check, + (__force __wsum)htonl(paylen)); + } + + /* reset pointers to inner headers */ + ip.hdr = skb_inner_network_header(skb); + l4.hdr = skb_inner_transport_header(skb); + + /* initialize inner IP header fields */ + if (ip.v4->version == 4) { + ip.v4->tot_len = 0; + ip.v4->check = 0; + } else { + ip.v6->payload_len = 0; + } + } + + /* determine offset of inner transport header */ + l4_offset = l4.hdr - skb->data; + + /* remove payload length from inner checksum */ + paylen = skb->len - l4_offset; + csum_replace_by_diff(&l4.tcp->check, (__force __wsum)htonl(paylen)); + + /* compute length of segmentation header */ + *hdr_len = (l4.tcp->doff * 4) + l4_offset; + + /* pull values out of skb_shinfo */ + gso_size = skb_shinfo(skb)->gso_size; + gso_segs = skb_shinfo(skb)->gso_segs; + + /* update GSO size and bytecount with header size */ + first->gso_segs = gso_segs; + first->bytecount += (first->gso_segs - 1) * *hdr_len; + + /* find the field values */ + cd_cmd = I40E_TX_CTX_DESC_TSO; + cd_tso_len = skb->len - *hdr_len; + cd_mss = gso_size; + *cd_type_cmd_tso_mss |= (cd_cmd << I40E_TXD_CTX_QW1_CMD_SHIFT) | + (cd_tso_len << I40E_TXD_CTX_QW1_TSO_LEN_SHIFT) | + (cd_mss << I40E_TXD_CTX_QW1_MSS_SHIFT); + return 1; +} + +/** + * i40e_tx_enable_csum - Enable Tx checksum offloads + * @skb: send buffer + * @tx_flags: pointer to Tx flags currently set + * @td_cmd: Tx descriptor command bits to set + * @td_offset: Tx descriptor header offsets to set + * @tx_ring: Tx descriptor ring + * @cd_tunneling: ptr to context desc bits + **/ +static int i40e_tx_enable_csum(struct sk_buff *skb, u32 *tx_flags, + u32 *td_cmd, u32 *td_offset, + struct i40e_ring *tx_ring, + u32 *cd_tunneling) +{ + union { + struct iphdr *v4; + struct ipv6hdr *v6; + unsigned char *hdr; + } ip; + union { + struct tcphdr *tcp; + struct udphdr *udp; + unsigned char *hdr; + } l4; + unsigned char *exthdr; + u32 offset, cmd = 0; + __be16 frag_off; + u8 l4_proto = 0; + + if (skb->ip_summed != CHECKSUM_PARTIAL) + return 0; + + ip.hdr = skb_network_header(skb); + l4.hdr = skb_transport_header(skb); + + /* compute outer L2 header size */ + offset = ((ip.hdr - skb->data) / 2) << I40E_TX_DESC_LENGTH_MACLEN_SHIFT; + + if (skb->encapsulation) { + u32 tunnel = 0; + /* define outer network header type */ + if (*tx_flags & I40E_TX_FLAGS_IPV4) { + tunnel |= (*tx_flags & I40E_TX_FLAGS_TSO) ? + I40E_TX_CTX_EXT_IP_IPV4 : + I40E_TX_CTX_EXT_IP_IPV4_NO_CSUM; + + l4_proto = ip.v4->protocol; + } else if (*tx_flags & I40E_TX_FLAGS_IPV6) { + tunnel |= I40E_TX_CTX_EXT_IP_IPV6; + + exthdr = ip.hdr + sizeof(*ip.v6); + l4_proto = ip.v6->nexthdr; + if (l4.hdr != exthdr) + ipv6_skip_exthdr(skb, exthdr - skb->data, + &l4_proto, &frag_off); + } + + /* define outer transport */ + switch (l4_proto) { + case IPPROTO_UDP: + tunnel |= I40E_TXD_CTX_UDP_TUNNELING; + *tx_flags |= I40E_TX_FLAGS_VXLAN_TUNNEL; + break; + case IPPROTO_GRE: + tunnel |= I40E_TXD_CTX_GRE_TUNNELING; + *tx_flags |= I40E_TX_FLAGS_VXLAN_TUNNEL; + break; + case IPPROTO_IPIP: + case IPPROTO_IPV6: + *tx_flags |= I40E_TX_FLAGS_VXLAN_TUNNEL; + l4.hdr = skb_inner_network_header(skb); + break; + default: + if (*tx_flags & I40E_TX_FLAGS_TSO) + return -1; + + skb_checksum_help(skb); + return 0; + } + + /* compute outer L3 header size */ + tunnel |= ((l4.hdr - ip.hdr) / 4) << + I40E_TXD_CTX_QW0_EXT_IPLEN_SHIFT; + + /* switch IP header pointer from outer to inner header */ + ip.hdr = skb_inner_network_header(skb); + + /* compute tunnel header size */ + tunnel |= ((ip.hdr - l4.hdr) / 2) << + I40E_TXD_CTX_QW0_NATLEN_SHIFT; + + /* indicate if we need to offload outer UDP header */ + if ((*tx_flags & I40E_TX_FLAGS_TSO) && + !(skb_shinfo(skb)->gso_type & SKB_GSO_PARTIAL) && + (skb_shinfo(skb)->gso_type & SKB_GSO_UDP_TUNNEL_CSUM)) + tunnel |= I40E_TXD_CTX_QW0_L4T_CS_MASK; + + /* record tunnel offload values */ + *cd_tunneling |= tunnel; + + /* switch L4 header pointer from outer to inner */ + l4.hdr = skb_inner_transport_header(skb); + l4_proto = 0; + + /* reset type as we transition from outer to inner headers */ + *tx_flags &= ~(I40E_TX_FLAGS_IPV4 | I40E_TX_FLAGS_IPV6); + if (ip.v4->version == 4) + *tx_flags |= I40E_TX_FLAGS_IPV4; + if (ip.v6->version == 6) + *tx_flags |= I40E_TX_FLAGS_IPV6; + } + + /* Enable IP checksum offloads */ + if (*tx_flags & I40E_TX_FLAGS_IPV4) { + l4_proto = ip.v4->protocol; + /* the stack computes the IP header already, the only time we + * need the hardware to recompute it is in the case of TSO. + */ + cmd |= (*tx_flags & I40E_TX_FLAGS_TSO) ? + I40E_TX_DESC_CMD_IIPT_IPV4_CSUM : + I40E_TX_DESC_CMD_IIPT_IPV4; + } else if (*tx_flags & I40E_TX_FLAGS_IPV6) { + cmd |= I40E_TX_DESC_CMD_IIPT_IPV6; + + exthdr = ip.hdr + sizeof(*ip.v6); + l4_proto = ip.v6->nexthdr; + if (l4.hdr != exthdr) + ipv6_skip_exthdr(skb, exthdr - skb->data, + &l4_proto, &frag_off); + } + + /* compute inner L3 header size */ + offset |= ((l4.hdr - ip.hdr) / 4) << I40E_TX_DESC_LENGTH_IPLEN_SHIFT; + + /* Enable L4 checksum offloads */ + switch (l4_proto) { + case IPPROTO_TCP: + /* enable checksum offloads */ + cmd |= I40E_TX_DESC_CMD_L4T_EOFT_TCP; + offset |= l4.tcp->doff << I40E_TX_DESC_LENGTH_L4_FC_LEN_SHIFT; + break; + case IPPROTO_SCTP: + /* enable SCTP checksum offload */ + cmd |= I40E_TX_DESC_CMD_L4T_EOFT_SCTP; + offset |= (sizeof(struct sctphdr) >> 2) << + I40E_TX_DESC_LENGTH_L4_FC_LEN_SHIFT; + break; + case IPPROTO_UDP: + /* enable UDP checksum offload */ + cmd |= I40E_TX_DESC_CMD_L4T_EOFT_UDP; + offset |= (sizeof(struct udphdr) >> 2) << + I40E_TX_DESC_LENGTH_L4_FC_LEN_SHIFT; + break; + default: + if (*tx_flags & I40E_TX_FLAGS_TSO) + return -1; + skb_checksum_help(skb); + return 0; + } + + *td_cmd |= cmd; + *td_offset |= offset; + + return 1; +} + +/** + * i40e_create_tx_ctx Build the Tx context descriptor + * @tx_ring: ring to create the descriptor on + * @cd_type_cmd_tso_mss: Quad Word 1 + * @cd_tunneling: Quad Word 0 - bits 0-31 + * @cd_l2tag2: Quad Word 0 - bits 32-63 + **/ +static void i40e_create_tx_ctx(struct i40e_ring *tx_ring, + const u64 cd_type_cmd_tso_mss, + const u32 cd_tunneling, const u32 cd_l2tag2) +{ + struct i40e_tx_context_desc *context_desc; + int i = tx_ring->next_to_use; + + if ((cd_type_cmd_tso_mss == I40E_TX_DESC_DTYPE_CONTEXT) && + !cd_tunneling && !cd_l2tag2) + return; + + /* grab the next descriptor */ + context_desc = I40E_TX_CTXTDESC(tx_ring, i); + + i++; + tx_ring->next_to_use = (i < tx_ring->count) ? i : 0; + + /* cpu_to_le32 and assign to struct fields */ + context_desc->tunneling_params = cpu_to_le32(cd_tunneling); + context_desc->l2tag2 = cpu_to_le16(cd_l2tag2); + context_desc->rsvd = cpu_to_le16(0); + context_desc->type_cmd_tso_mss = cpu_to_le64(cd_type_cmd_tso_mss); +} + +/** + * __i40evf_chk_linearize - Check if there are more than 8 buffers per packet + * @skb: send buffer + * + * Note: Our HW can't DMA more than 8 buffers to build a packet on the wire + * and so we need to figure out the cases where we need to linearize the skb. + * + * For TSO we need to count the TSO header and segment payload separately. + * As such we need to check cases where we have 7 fragments or more as we + * can potentially require 9 DMA transactions, 1 for the TSO header, 1 for + * the segment payload in the first descriptor, and another 7 for the + * fragments. + **/ +bool __i40evf_chk_linearize(struct sk_buff *skb) +{ + const struct skb_frag_struct *frag, *stale; + int nr_frags, sum; + + /* no need to check if number of frags is less than 7 */ + nr_frags = skb_shinfo(skb)->nr_frags; + if (nr_frags < (I40E_MAX_BUFFER_TXD - 1)) + return false; + + /* We need to walk through the list and validate that each group + * of 6 fragments totals at least gso_size. + */ + nr_frags -= I40E_MAX_BUFFER_TXD - 2; + frag = &skb_shinfo(skb)->frags[0]; + + /* Initialize size to the negative value of gso_size minus 1. We + * use this as the worst case scenerio in which the frag ahead + * of us only provides one byte which is why we are limited to 6 + * descriptors for a single transmit as the header and previous + * fragment are already consuming 2 descriptors. + */ + sum = 1 - skb_shinfo(skb)->gso_size; + + /* Add size of frags 0 through 4 to create our initial sum */ + sum += skb_frag_size(frag++); + sum += skb_frag_size(frag++); + sum += skb_frag_size(frag++); + sum += skb_frag_size(frag++); + sum += skb_frag_size(frag++); + + /* Walk through fragments adding latest fragment, testing it, and + * then removing stale fragments from the sum. + */ + for (stale = &skb_shinfo(skb)->frags[0];; stale++) { + int stale_size = skb_frag_size(stale); + + sum += skb_frag_size(frag++); + + /* The stale fragment may present us with a smaller + * descriptor than the actual fragment size. To account + * for that we need to remove all the data on the front and + * figure out what the remainder would be in the last + * descriptor associated with the fragment. + */ + if (stale_size > I40E_MAX_DATA_PER_TXD) { + int align_pad = -(stale->page_offset) & + (I40E_MAX_READ_REQ_SIZE - 1); + + sum -= align_pad; + stale_size -= align_pad; + + do { + sum -= I40E_MAX_DATA_PER_TXD_ALIGNED; + stale_size -= I40E_MAX_DATA_PER_TXD_ALIGNED; + } while (stale_size > I40E_MAX_DATA_PER_TXD); + } + + /* if sum is negative we failed to make sufficient progress */ + if (sum < 0) + return true; + + if (!nr_frags--) + break; + + sum -= stale_size; + } + + return false; +} + +/** + * __i40evf_maybe_stop_tx - 2nd level check for tx stop conditions + * @tx_ring: the ring to be checked + * @size: the size buffer we want to assure is available + * + * Returns -EBUSY if a stop is needed, else 0 + **/ +int __i40evf_maybe_stop_tx(struct i40e_ring *tx_ring, int size) +{ + netif_stop_subqueue(tx_ring->netdev, tx_ring->queue_index); + /* Memory barrier before checking head and tail */ + smp_mb(); + + /* Check again in a case another CPU has just made room available. */ + if (likely(I40E_DESC_UNUSED(tx_ring) < size)) + return -EBUSY; + + /* A reprieve! - use start_queue because it doesn't call schedule */ + netif_start_subqueue(tx_ring->netdev, tx_ring->queue_index); + ++tx_ring->tx_stats.restart_queue; + return 0; +} + +/** + * i40evf_tx_map - Build the Tx descriptor + * @tx_ring: ring to send buffer on + * @skb: send buffer + * @first: first buffer info buffer to use + * @tx_flags: collected send information + * @hdr_len: size of the packet header + * @td_cmd: the command field in the descriptor + * @td_offset: offset for checksum or crc + **/ +static inline void i40evf_tx_map(struct i40e_ring *tx_ring, struct sk_buff *skb, + struct i40e_tx_buffer *first, u32 tx_flags, + const u8 hdr_len, u32 td_cmd, u32 td_offset) +{ + unsigned int data_len = skb->data_len; + unsigned int size = skb_headlen(skb); + struct skb_frag_struct *frag; + struct i40e_tx_buffer *tx_bi; + struct i40e_tx_desc *tx_desc; + u16 i = tx_ring->next_to_use; + u32 td_tag = 0; + dma_addr_t dma; + + if (tx_flags & I40E_TX_FLAGS_HW_VLAN) { + td_cmd |= I40E_TX_DESC_CMD_IL2TAG1; + td_tag = (tx_flags & I40E_TX_FLAGS_VLAN_MASK) >> + I40E_TX_FLAGS_VLAN_SHIFT; + } + + first->tx_flags = tx_flags; + + dma = dma_map_single(tx_ring->dev, skb->data, size, DMA_TO_DEVICE); + + tx_desc = I40E_TX_DESC(tx_ring, i); + tx_bi = first; + + for (frag = &skb_shinfo(skb)->frags[0];; frag++) { + unsigned int max_data = I40E_MAX_DATA_PER_TXD_ALIGNED; + + if (dma_mapping_error(tx_ring->dev, dma)) + goto dma_error; + + /* record length, and DMA address */ + dma_unmap_len_set(tx_bi, len, size); + dma_unmap_addr_set(tx_bi, dma, dma); + + /* align size to end of page */ + max_data += -dma & (I40E_MAX_READ_REQ_SIZE - 1); + tx_desc->buffer_addr = cpu_to_le64(dma); + + while (unlikely(size > I40E_MAX_DATA_PER_TXD)) { + tx_desc->cmd_type_offset_bsz = + build_ctob(td_cmd, td_offset, + max_data, td_tag); + + tx_desc++; + i++; + + if (i == tx_ring->count) { + tx_desc = I40E_TX_DESC(tx_ring, 0); + i = 0; + } + + dma += max_data; + size -= max_data; + + max_data = I40E_MAX_DATA_PER_TXD_ALIGNED; + tx_desc->buffer_addr = cpu_to_le64(dma); + } + + if (likely(!data_len)) + break; + + tx_desc->cmd_type_offset_bsz = build_ctob(td_cmd, td_offset, + size, td_tag); + + tx_desc++; + i++; + + if (i == tx_ring->count) { + tx_desc = I40E_TX_DESC(tx_ring, 0); + i = 0; + } + + size = skb_frag_size(frag); + data_len -= size; + + dma = skb_frag_dma_map(tx_ring->dev, frag, 0, size, + DMA_TO_DEVICE); + + tx_bi = &tx_ring->tx_bi[i]; + } + + netdev_tx_sent_queue(txring_txq(tx_ring), first->bytecount); + + i++; + if (i == tx_ring->count) + i = 0; + + tx_ring->next_to_use = i; + + i40e_maybe_stop_tx(tx_ring, DESC_NEEDED); + + /* write last descriptor with RS and EOP bits */ + td_cmd |= I40E_TXD_CMD; + tx_desc->cmd_type_offset_bsz = + build_ctob(td_cmd, td_offset, size, td_tag); + + /* Force memory writes to complete before letting h/w know there + * are new descriptors to fetch. + * + * We also use this memory barrier to make certain all of the + * status bits have been updated before next_to_watch is written. + */ + wmb(); + + /* set next_to_watch value indicating a packet is present */ + first->next_to_watch = tx_desc; + + /* notify HW of packet */ + if (netif_xmit_stopped(txring_txq(tx_ring)) || !skb->xmit_more) { + writel(i, tx_ring->tail); + + /* we need this if more than one processor can write to our tail + * at a time, it synchronizes IO on IA64/Altix systems + */ + mmiowb(); + } + + return; + +dma_error: + dev_info(tx_ring->dev, "TX DMA map failed\n"); + + /* clear dma mappings for failed tx_bi map */ + for (;;) { + tx_bi = &tx_ring->tx_bi[i]; + i40e_unmap_and_free_tx_resource(tx_ring, tx_bi); + if (tx_bi == first) + break; + if (i == 0) + i = tx_ring->count; + i--; + } + + tx_ring->next_to_use = i; +} + +/** + * i40e_xmit_frame_ring - Sends buffer on Tx ring + * @skb: send buffer + * @tx_ring: ring to send buffer on + * + * Returns NETDEV_TX_OK if sent, else an error code + **/ +static netdev_tx_t i40e_xmit_frame_ring(struct sk_buff *skb, + struct i40e_ring *tx_ring) +{ + u64 cd_type_cmd_tso_mss = I40E_TX_DESC_DTYPE_CONTEXT; + u32 cd_tunneling = 0, cd_l2tag2 = 0; + struct i40e_tx_buffer *first; + u32 td_offset = 0; + u32 tx_flags = 0; + __be16 protocol; + u32 td_cmd = 0; + u8 hdr_len = 0; + int tso, count; + + /* prefetch the data, we'll need it later */ + prefetch(skb->data); + + i40e_trace(xmit_frame_ring, skb, tx_ring); + + count = i40e_xmit_descriptor_count(skb); + if (i40e_chk_linearize(skb, count)) { + if (__skb_linearize(skb)) { + dev_kfree_skb_any(skb); + return NETDEV_TX_OK; + } + count = i40e_txd_use_count(skb->len); + tx_ring->tx_stats.tx_linearize++; + } + + /* need: 1 descriptor per page * PAGE_SIZE/I40E_MAX_DATA_PER_TXD, + * + 1 desc for skb_head_len/I40E_MAX_DATA_PER_TXD, + * + 4 desc gap to avoid the cache line where head is, + * + 1 desc for context descriptor, + * otherwise try next time + */ + if (i40e_maybe_stop_tx(tx_ring, count + 4 + 1)) { + tx_ring->tx_stats.tx_busy++; + return NETDEV_TX_BUSY; + } + + /* record the location of the first descriptor for this packet */ + first = &tx_ring->tx_bi[tx_ring->next_to_use]; + first->skb = skb; + first->bytecount = skb->len; + first->gso_segs = 1; + + /* prepare the xmit flags */ + if (i40evf_tx_prepare_vlan_flags(skb, tx_ring, &tx_flags)) + goto out_drop; + + /* obtain protocol of skb */ + protocol = vlan_get_protocol(skb); + + /* setup IPv4/IPv6 offloads */ + if (protocol == htons(ETH_P_IP)) + tx_flags |= I40E_TX_FLAGS_IPV4; + else if (protocol == htons(ETH_P_IPV6)) + tx_flags |= I40E_TX_FLAGS_IPV6; + + tso = i40e_tso(first, &hdr_len, &cd_type_cmd_tso_mss); + + if (tso < 0) + goto out_drop; + else if (tso) + tx_flags |= I40E_TX_FLAGS_TSO; + + /* Always offload the checksum, since it's in the data descriptor */ + tso = i40e_tx_enable_csum(skb, &tx_flags, &td_cmd, &td_offset, + tx_ring, &cd_tunneling); + if (tso < 0) + goto out_drop; + + skb_tx_timestamp(skb); + + /* always enable CRC insertion offload */ + td_cmd |= I40E_TX_DESC_CMD_ICRC; + + i40e_create_tx_ctx(tx_ring, cd_type_cmd_tso_mss, + cd_tunneling, cd_l2tag2); + + i40evf_tx_map(tx_ring, skb, first, tx_flags, hdr_len, + td_cmd, td_offset); + + return NETDEV_TX_OK; + +out_drop: + i40e_trace(xmit_frame_ring_drop, first->skb, tx_ring); + dev_kfree_skb_any(first->skb); + first->skb = NULL; + return NETDEV_TX_OK; +} + +/** + * i40evf_xmit_frame - Selects the correct VSI and Tx queue to send buffer + * @skb: send buffer + * @netdev: network interface device structure + * + * Returns NETDEV_TX_OK if sent, else an error code + **/ +netdev_tx_t i40evf_xmit_frame(struct sk_buff *skb, struct net_device *netdev) +{ + struct i40evf_adapter *adapter = netdev_priv(netdev); + struct i40e_ring *tx_ring = &adapter->tx_rings[skb->queue_mapping]; + + /* hardware can't handle really short frames, hardware padding works + * beyond this point + */ + if (unlikely(skb->len < I40E_MIN_TX_LEN)) { + if (skb_pad(skb, I40E_MIN_TX_LEN - skb->len)) + return NETDEV_TX_OK; + skb->len = I40E_MIN_TX_LEN; + skb_set_tail_pointer(skb, I40E_MIN_TX_LEN); + } + + return i40e_xmit_frame_ring(skb, tx_ring); +} |