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android-kvm / linux / 789b6cc2a5f9123b9c549b886fdc47c865cfe0ba / . / drivers / net / ethernet / intel / iavf / iavf_txrx.c
blob: 3525eab8e9f9a8bbd4908576760a8a84b28fd108 [file] [log] [blame]
// SPDX-License-Identifier: GPL-2.0
/* Copyright(c) 2013 - 2018 Intel Corporation. */
#include <linux/prefetch.h>
#include "iavf.h"
#include "iavf_trace.h"
#include "iavf_prototype.h"
static inline __le64 build_ctob(u32 td_cmd, u32 td_offset, unsigned int size,
u32 td_tag)
{
return cpu_to_le64(IAVF_TX_DESC_DTYPE_DATA |
((u64)td_cmd << IAVF_TXD_QW1_CMD_SHIFT) |
((u64)td_offset << IAVF_TXD_QW1_OFFSET_SHIFT) |
((u64)size << IAVF_TXD_QW1_TX_BUF_SZ_SHIFT) |
((u64)td_tag << IAVF_TXD_QW1_L2TAG1_SHIFT));
}
#define IAVF_TXD_CMD (IAVF_TX_DESC_CMD_EOP | IAVF_TX_DESC_CMD_RS)
/**
* iavf_unmap_and_free_tx_resource - Release a Tx buffer
* @ring: the ring that owns the buffer
* @tx_buffer: the buffer to free
**/
static void iavf_unmap_and_free_tx_resource(struct iavf_ring *ring,
struct iavf_tx_buffer *tx_buffer)
{
if (tx_buffer->skb) {
if (tx_buffer->tx_flags & IAVF_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 */
}
/**
* iavf_clean_tx_ring - Free any empty Tx buffers
* @tx_ring: ring to be cleaned
**/
void iavf_clean_tx_ring(struct iavf_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++)
iavf_unmap_and_free_tx_resource(tx_ring, &tx_ring->tx_bi[i]);
bi_size = sizeof(struct iavf_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));
}
/**
* iavf_free_tx_resources - Free Tx resources per queue
* @tx_ring: Tx descriptor ring for a specific queue
*
* Free all transmit software resources
**/
void iavf_free_tx_resources(struct iavf_ring *tx_ring)
{
iavf_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;
}
}
/**
* iavf_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 iavf_get_tx_pending(struct iavf_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;
}
/**
* iavf_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 iavf_detect_recover_hung(struct iavf_vsi *vsi)
{
struct iavf_ring *tx_ring = NULL;
struct net_device *netdev;
unsigned int i;
int packets;
if (!vsi)
return;
if (test_bit(__IAVF_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) {
iavf_force_wb(vsi, tx_ring->q_vector);
continue;
}
/* Memory barrier between read of packet count and call
* to iavf_get_tx_pending()
*/
smp_rmb();
tx_ring->tx_stats.prev_pkt_ctr =
iavf_get_tx_pending(tx_ring, true) ? packets : -1;
}
}
}
#define WB_STRIDE 4
/**
* iavf_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 iavf_clean_tx_irq(struct iavf_vsi *vsi,
struct iavf_ring *tx_ring, int napi_budget)
{
int i = tx_ring->next_to_clean;
struct iavf_tx_buffer *tx_buf;
struct iavf_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 = IAVF_TX_DESC(tx_ring, i);
i -= tx_ring->count;
do {
struct iavf_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();
iavf_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(IAVF_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) {
iavf_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 = IAVF_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 = IAVF_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 & IAVF_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 = iavf_get_tx_pending(tx_ring, false);
if (budget &&
((j / WB_STRIDE) == 0) && (j > 0) &&
!test_bit(__IAVF_VSI_DOWN, vsi->state) &&
(IAVF_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) &&
(IAVF_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(__IAVF_VSI_DOWN, vsi->state)) {
netif_wake_subqueue(tx_ring->netdev,
tx_ring->queue_index);
++tx_ring->tx_stats.restart_queue;
}
}
return !!budget;
}
/**
* iavf_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 iavf_enable_wb_on_itr(struct iavf_vsi *vsi,
struct iavf_q_vector *q_vector)
{
u16 flags = q_vector->tx.ring[0].flags;
u32 val;
if (!(flags & IAVF_TXR_FLAGS_WB_ON_ITR))
return;
if (q_vector->arm_wb_state)
return;
val = IAVF_VFINT_DYN_CTLN1_WB_ON_ITR_MASK |
IAVF_VFINT_DYN_CTLN1_ITR_INDX_MASK; /* set noitr */
wr32(&vsi->back->hw,
IAVF_VFINT_DYN_CTLN1(q_vector->reg_idx), val);
q_vector->arm_wb_state = true;
}
/**
* iavf_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 iavf_force_wb(struct iavf_vsi *vsi, struct iavf_q_vector *q_vector)
{
u32 val = IAVF_VFINT_DYN_CTLN1_INTENA_MASK |
IAVF_VFINT_DYN_CTLN1_ITR_INDX_MASK | /* set noitr */
IAVF_VFINT_DYN_CTLN1_SWINT_TRIG_MASK |
IAVF_VFINT_DYN_CTLN1_SW_ITR_INDX_ENA_MASK
/* allow 00 to be written to the index */;
wr32(&vsi->back->hw,
IAVF_VFINT_DYN_CTLN1(q_vector->reg_idx),
val);
}
static inline bool iavf_container_is_rx(struct iavf_q_vector *q_vector,
struct iavf_ring_container *rc)
{
return &q_vector->rx == rc;
}
static inline unsigned int iavf_itr_divisor(struct iavf_q_vector *q_vector)
{
unsigned int divisor;
switch (q_vector->adapter->link_speed) {
case VIRTCHNL_LINK_SPEED_40GB:
divisor = IAVF_ITR_ADAPTIVE_MIN_INC * 1024;
break;
case VIRTCHNL_LINK_SPEED_25GB:
case VIRTCHNL_LINK_SPEED_20GB:
divisor = IAVF_ITR_ADAPTIVE_MIN_INC * 512;
break;
default:
case VIRTCHNL_LINK_SPEED_10GB:
divisor = IAVF_ITR_ADAPTIVE_MIN_INC * 256;
break;
case VIRTCHNL_LINK_SPEED_1GB:
case VIRTCHNL_LINK_SPEED_100MB:
divisor = IAVF_ITR_ADAPTIVE_MIN_INC * 32;
break;
}
return divisor;
}
/**
* iavf_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 iavf_update_itr(struct iavf_q_vector *q_vector,
struct iavf_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 = iavf_container_is_rx(q_vector, rc) ?
IAVF_ITR_ADAPTIVE_MIN_USECS | IAVF_ITR_ADAPTIVE_LATENCY :
IAVF_ITR_ADAPTIVE_MAX_USECS | IAVF_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 (iavf_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 & IAVF_ITR_ADAPTIVE_LATENCY)) {
itr = IAVF_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 == IAVF_ITR_ADAPTIVE_MAX_USECS &&
(q_vector->rx.target_itr & IAVF_ITR_MASK) ==
IAVF_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 &= ~IAVF_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 + IAVF_ITR_ADAPTIVE_MIN_INC;
if ((itr & IAVF_ITR_MASK) > IAVF_ITR_ADAPTIVE_MAX_USECS) {
itr &= IAVF_ITR_ADAPTIVE_LATENCY;
itr += IAVF_ITR_ADAPTIVE_MAX_USECS;
}
goto clear_counts;
}
if (packets <= 256) {
itr = min(q_vector->tx.current_itr, q_vector->rx.current_itr);
itr &= IAVF_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 &= IAVF_ITR_MASK;
if (itr < IAVF_ITR_ADAPTIVE_MIN_USECS)
itr = IAVF_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 = IAVF_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 & IAVF_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, iavf_itr_divisor(q_vector)) *
IAVF_ITR_ADAPTIVE_MIN_INC;
if ((itr & IAVF_ITR_MASK) > IAVF_ITR_ADAPTIVE_MAX_USECS) {
itr &= IAVF_ITR_ADAPTIVE_LATENCY;
itr += IAVF_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;
}
/**
* iavf_setup_tx_descriptors - Allocate the Tx descriptors
* @tx_ring: the tx ring to set up
*
* Return 0 on success, negative on error
**/
int iavf_setup_tx_descriptors(struct iavf_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 iavf_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 iavf_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;
}
/**
* iavf_clean_rx_ring - Free Rx buffers
* @rx_ring: ring to be cleaned
**/
void iavf_clean_rx_ring(struct iavf_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 iavf_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,
iavf_rx_pg_size(rx_ring),
DMA_FROM_DEVICE,
IAVF_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 iavf_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;
}
/**
* iavf_free_rx_resources - Free Rx resources
* @rx_ring: ring to clean the resources from
*
* Free all receive software resources
**/
void iavf_free_rx_resources(struct iavf_ring *rx_ring)
{
iavf_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;
}
}
/**
* iavf_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 iavf_setup_rx_descriptors(struct iavf_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 iavf_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 iavf_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;
}
/**
* iavf_release_rx_desc - Store the new tail and head values
* @rx_ring: ring to bump
* @val: new head index
**/
static inline void iavf_release_rx_desc(struct iavf_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);
}
/**
* iavf_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 iavf_rx_offset(struct iavf_ring *rx_ring)
{
return ring_uses_build_skb(rx_ring) ? IAVF_SKB_PAD : 0;
}
/**
* iavf_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 iavf_alloc_mapped_page(struct iavf_ring *rx_ring,
struct iavf_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(iavf_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,
iavf_rx_pg_size(rx_ring),
DMA_FROM_DEVICE,
IAVF_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, iavf_rx_pg_order(rx_ring));
rx_ring->rx_stats.alloc_page_failed++;
return false;
}
bi->dma = dma;
bi->page = page;
bi->page_offset = iavf_rx_offset(rx_ring);
/* initialize pagecnt_bias to 1 representing we fully own page */
bi->pagecnt_bias = 1;
return true;
}
/**
* iavf_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 iavf_receive_skb(struct iavf_ring *rx_ring,
struct sk_buff *skb, u16 vlan_tag)
{
struct iavf_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);
}
/**
* iavf_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 iavf_alloc_rx_buffers(struct iavf_ring *rx_ring, u16 cleaned_count)
{
u16 ntu = rx_ring->next_to_use;
union iavf_rx_desc *rx_desc;
struct iavf_rx_buffer *bi;
/* do nothing if no valid netdev defined */
if (!rx_ring->netdev || !cleaned_count)
return false;
rx_desc = IAVF_RX_DESC(rx_ring, ntu);
bi = &rx_ring->rx_bi[ntu];
do {
if (!iavf_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 = IAVF_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)
iavf_release_rx_desc(rx_ring, ntu);
return false;
no_buffers:
if (rx_ring->next_to_use != ntu)
iavf_release_rx_desc(rx_ring, ntu);
/* make sure to come back via polling to try again after
* allocation failure
*/
return true;
}
/**
* iavf_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 iavf_rx_checksum(struct iavf_vsi *vsi,
struct sk_buff *skb,
union iavf_rx_desc *rx_desc)
{
struct iavf_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 & IAVF_RXD_QW1_PTYPE_MASK) >> IAVF_RXD_QW1_PTYPE_SHIFT;
rx_error = (qword & IAVF_RXD_QW1_ERROR_MASK) >>
IAVF_RXD_QW1_ERROR_SHIFT;
rx_status = (qword & IAVF_RXD_QW1_STATUS_MASK) >>
IAVF_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(IAVF_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 == IAVF_RX_PTYPE_OUTER_IP) &&
(decoded.outer_ip_ver == IAVF_RX_PTYPE_OUTER_IPV4);
ipv6 = (decoded.outer_ip == IAVF_RX_PTYPE_OUTER_IP) &&
(decoded.outer_ip_ver == IAVF_RX_PTYPE_OUTER_IPV6);
if (ipv4 &&
(rx_error & (BIT(IAVF_RX_DESC_ERROR_IPE_SHIFT) |
BIT(IAVF_RX_DESC_ERROR_EIPE_SHIFT))))
goto checksum_fail;
/* likely incorrect csum if alternate IP extension headers found */
if (ipv6 &&
rx_status & BIT(IAVF_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(IAVF_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(IAVF_RX_DESC_ERROR_PPRS_SHIFT))
return;
/* Only report checksum unnecessary for TCP, UDP, or SCTP */
switch (decoded.inner_prot) {
case IAVF_RX_PTYPE_INNER_PROT_TCP:
case IAVF_RX_PTYPE_INNER_PROT_UDP:
case IAVF_RX_PTYPE_INNER_PROT_SCTP:
skb->ip_summed = CHECKSUM_UNNECESSARY;
fallthrough;
default:
break;
}
return;
checksum_fail:
vsi->back->hw_csum_rx_error++;
}
/**
* iavf_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 iavf_ptype_to_htype(u8 ptype)
{
struct iavf_rx_ptype_decoded decoded = decode_rx_desc_ptype(ptype);
if (!decoded.known)
return PKT_HASH_TYPE_NONE;
if (decoded.outer_ip == IAVF_RX_PTYPE_OUTER_IP &&
decoded.payload_layer == IAVF_RX_PTYPE_PAYLOAD_LAYER_PAY4)
return PKT_HASH_TYPE_L4;
else if (decoded.outer_ip == IAVF_RX_PTYPE_OUTER_IP &&
decoded.payload_layer == IAVF_RX_PTYPE_PAYLOAD_LAYER_PAY3)
return PKT_HASH_TYPE_L3;
else
return PKT_HASH_TYPE_L2;
}
/**
* iavf_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 iavf_rx_hash(struct iavf_ring *ring,
union iavf_rx_desc *rx_desc,
struct sk_buff *skb,
u8 rx_ptype)
{
u32 hash;
const __le64 rss_mask =
cpu_to_le64((u64)IAVF_RX_DESC_FLTSTAT_RSS_HASH <<
IAVF_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, iavf_ptype_to_htype(rx_ptype));
}
}
/**
* iavf_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 iavf_process_skb_fields(struct iavf_ring *rx_ring,
union iavf_rx_desc *rx_desc, struct sk_buff *skb,
u8 rx_ptype)
{
iavf_rx_hash(rx_ring, rx_desc, skb, rx_ptype);
iavf_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);
}
/**
* iavf_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 iavf_cleanup_headers(struct iavf_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;
}
/**
* iavf_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 iavf_reuse_rx_page(struct iavf_ring *rx_ring,
struct iavf_rx_buffer *old_buff)
{
struct iavf_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;
}
/**
* iavf_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 iavf_can_reuse_rx_page(struct iavf_rx_buffer *rx_buffer)
{
unsigned int pagecnt_bias = rx_buffer->pagecnt_bias;
struct page *page = rx_buffer->page;
/* Is any reuse possible? */
if (!dev_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 IAVF_LAST_OFFSET \
(SKB_WITH_OVERHEAD(PAGE_SIZE) - IAVF_RXBUFFER_2048)
if (rx_buffer->page_offset > IAVF_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;
}
/**
* iavf_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 iavf_add_rx_frag(struct iavf_ring *rx_ring,
struct iavf_rx_buffer *rx_buffer,
struct sk_buff *skb,
unsigned int size)
{
#if (PAGE_SIZE < 8192)
unsigned int truesize = iavf_rx_pg_size(rx_ring) / 2;
#else
unsigned int truesize = SKB_DATA_ALIGN(size + iavf_rx_offset(rx_ring));
#endif
if (!size)
return;
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
}
/**
* iavf_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 iavf_rx_buffer *iavf_get_rx_buffer(struct iavf_ring *rx_ring,
const unsigned int size)
{
struct iavf_rx_buffer *rx_buffer;
if (!size)
return NULL;
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;
}
/**
* iavf_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 *iavf_construct_skb(struct iavf_ring *rx_ring,
struct iavf_rx_buffer *rx_buffer,
unsigned int size)
{
void *va;
#if (PAGE_SIZE < 8192)
unsigned int truesize = iavf_rx_pg_size(rx_ring) / 2;
#else
unsigned int truesize = SKB_DATA_ALIGN(size);
#endif
unsigned int headlen;
struct sk_buff *skb;
if (!rx_buffer)
return NULL;
/* prefetch first cache line of first page */
va = page_address(rx_buffer->page) + rx_buffer->page_offset;
net_prefetch(va);
/* allocate a skb to store the frags */
skb = __napi_alloc_skb(&rx_ring->q_vector->napi,
IAVF_RX_HDR_SIZE,
GFP_ATOMIC | __GFP_NOWARN);
if (unlikely(!skb))
return NULL;
/* Determine available headroom for copy */
headlen = size;
if (headlen > IAVF_RX_HDR_SIZE)
headlen = eth_get_headlen(skb->dev, va, IAVF_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;
}
/**
* iavf_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 *iavf_build_skb(struct iavf_ring *rx_ring,
struct iavf_rx_buffer *rx_buffer,
unsigned int size)
{
void *va;
#if (PAGE_SIZE < 8192)
unsigned int truesize = iavf_rx_pg_size(rx_ring) / 2;
#else
unsigned int truesize = SKB_DATA_ALIGN(sizeof(struct skb_shared_info)) +
SKB_DATA_ALIGN(IAVF_SKB_PAD + size);
#endif
struct sk_buff *skb;
if (!rx_buffer)
return NULL;
/* prefetch first cache line of first page */
va = page_address(rx_buffer->page) + rx_buffer->page_offset;
net_prefetch(va);
/* build an skb around the page buffer */
skb = build_skb(va - IAVF_SKB_PAD, truesize);
if (unlikely(!skb))
return NULL;
/* update pointers within the skb to store the data */
skb_reserve(skb, IAVF_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;
}
/**
* iavf_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 iavf_put_rx_buffer(struct iavf_ring *rx_ring,
struct iavf_rx_buffer *rx_buffer)
{
if (!rx_buffer)
return;
if (iavf_can_reuse_rx_page(rx_buffer)) {
/* hand second half of page back to the ring */
iavf_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,
iavf_rx_pg_size(rx_ring),
DMA_FROM_DEVICE, IAVF_RX_DMA_ATTR);
__page_frag_cache_drain(rx_buffer->page,
rx_buffer->pagecnt_bias);
}
/* clear contents of buffer_info */
rx_buffer->page = NULL;
}
/**
* iavf_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 iavf_is_non_eop(struct iavf_ring *rx_ring,
union iavf_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(IAVF_RX_DESC(rx_ring, ntc));
/* if we are the last buffer then there is nothing else to do */
#define IAVF_RXD_EOF BIT(IAVF_RX_DESC_STATUS_EOF_SHIFT)
if (likely(iavf_test_staterr(rx_desc, IAVF_RXD_EOF)))
return false;
rx_ring->rx_stats.non_eop_descs++;
return true;
}
/**
* iavf_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 iavf_clean_rx_irq(struct iavf_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 = IAVF_DESC_UNUSED(rx_ring);
bool failure = false;
while (likely(total_rx_packets < (unsigned int)budget)) {
struct iavf_rx_buffer *rx_buffer;
union iavf_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 >= IAVF_RX_BUFFER_WRITE) {
failure = failure ||
iavf_alloc_rx_buffers(rx_ring, cleaned_count);
cleaned_count = 0;
}
rx_desc = IAVF_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();
#define IAVF_RXD_DD BIT(IAVF_RX_DESC_STATUS_DD_SHIFT)
if (!iavf_test_staterr(rx_desc, IAVF_RXD_DD))
break;
size = (qword & IAVF_RXD_QW1_LENGTH_PBUF_MASK) >>
IAVF_RXD_QW1_LENGTH_PBUF_SHIFT;
iavf_trace(clean_rx_irq, rx_ring, rx_desc, skb);
rx_buffer = iavf_get_rx_buffer(rx_ring, size);
/* retrieve a buffer from the ring */
if (skb)
iavf_add_rx_frag(rx_ring, rx_buffer, skb, size);
else if (ring_uses_build_skb(rx_ring))
skb = iavf_build_skb(rx_ring, rx_buffer, size);
else
skb = iavf_construct_skb(rx_ring, rx_buffer, size);
/* exit if we failed to retrieve a buffer */
if (!skb) {
rx_ring->rx_stats.alloc_buff_failed++;
if (rx_buffer)
rx_buffer->pagecnt_bias++;
break;
}
iavf_put_rx_buffer(rx_ring, rx_buffer);
cleaned_count++;
if (iavf_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
* IAVF_RX_DESC_ERROR_RXE_SHIFT, since it is the zeroth bit in
* the error field
*/
if (unlikely(iavf_test_staterr(rx_desc, BIT(IAVF_RXD_QW1_ERROR_SHIFT)))) {
dev_kfree_skb_any(skb);
skb = NULL;
continue;
}
if (iavf_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 & IAVF_RXD_QW1_PTYPE_MASK) >>
IAVF_RXD_QW1_PTYPE_SHIFT;
/* populate checksum, VLAN, and protocol */
iavf_process_skb_fields(rx_ring, rx_desc, skb, rx_ptype);
vlan_tag = (qword & BIT(IAVF_RX_DESC_STATUS_L2TAG1P_SHIFT)) ?
le16_to_cpu(rx_desc->wb.qword0.lo_dword.l2tag1) : 0;
iavf_trace(clean_rx_irq_rx, rx_ring, rx_desc, skb);
iavf_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 iavf_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 &= IAVF_ITR_MASK;
val = IAVF_VFINT_DYN_CTLN1_INTENA_MASK |
(type << IAVF_VFINT_DYN_CTLN1_ITR_INDX_SHIFT) |
(itr << (IAVF_VFINT_DYN_CTLN1_INTERVAL_SHIFT - 1));
return val;
}
/* a small macro to shorten up some long lines */
#define INTREG IAVF_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
/**
* iavf_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 iavf_update_enable_itr(struct iavf_vsi *vsi,
struct iavf_q_vector *q_vector)
{
struct iavf_hw *hw = &vsi->back->hw;
u32 intval;
/* These will do nothing if dynamic updates are not enabled */
iavf_update_itr(q_vector, &q_vector->tx);
iavf_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 = iavf_buildreg_itr(IAVF_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 = iavf_buildreg_itr(IAVF_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 = iavf_buildreg_itr(IAVF_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 = iavf_buildreg_itr(IAVF_ITR_NONE, 0);
if (q_vector->itr_countdown)
q_vector->itr_countdown--;
}
if (!test_bit(__IAVF_VSI_DOWN, vsi->state))
wr32(hw, INTREG(q_vector->reg_idx), intval);
}
/**
* iavf_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 iavf_napi_poll(struct napi_struct *napi, int budget)
{
struct iavf_q_vector *q_vector =
container_of(napi, struct iavf_q_vector, napi);
struct iavf_vsi *vsi = q_vector->vsi;
struct iavf_ring *ring;
bool clean_complete = true;
bool arm_wb = false;
int budget_per_ring;
int work_done = 0;
if (test_bit(__IAVF_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.
*/
iavf_for_each_ring(ring, q_vector->tx) {
if (!iavf_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);
iavf_for_each_ring(ring, q_vector->rx) {
int cleaned = iavf_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 */
iavf_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++;
iavf_enable_wb_on_itr(vsi, q_vector);
}
return budget;
}
if (vsi->back->flags & IAVF_TXR_FLAGS_WB_ON_ITR)
q_vector->arm_wb_state = false;
/* Exit the polling mode, but don't re-enable interrupts if stack might
* poll us due to busy-polling
*/
if (likely(napi_complete_done(napi, work_done)))
iavf_update_enable_itr(vsi, q_vector);
return min(work_done, budget - 1);
}
/**
* iavf_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 iavf_tx_prepare_vlan_flags(struct sk_buff *skb,
struct iavf_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) << IAVF_TX_FLAGS_VLAN_SHIFT;
tx_flags |= IAVF_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) << IAVF_TX_FLAGS_VLAN_SHIFT;
tx_flags |= IAVF_TX_FLAGS_SW_VLAN;
}
out:
*flags = tx_flags;
return 0;
}
/**
* iavf_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 iavf_tso(struct iavf_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;
if (skb_shinfo(skb)->gso_type & SKB_GSO_UDP_L4) {
csum_replace_by_diff(&l4.udp->check,
(__force __wsum)htonl(paylen));
/* compute length of UDP segmentation header */
*hdr_len = (u8)sizeof(l4.udp) + l4_offset;
} else {
csum_replace_by_diff(&l4.tcp->check,
(__force __wsum)htonl(paylen));
/* compute length of TCP segmentation header */
*hdr_len = (u8)((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 = IAVF_TX_CTX_DESC_TSO;
cd_tso_len = skb->len - *hdr_len;
cd_mss = gso_size;
*cd_type_cmd_tso_mss |= (cd_cmd << IAVF_TXD_CTX_QW1_CMD_SHIFT) |
(cd_tso_len << IAVF_TXD_CTX_QW1_TSO_LEN_SHIFT) |
(cd_mss << IAVF_TXD_CTX_QW1_MSS_SHIFT);
return 1;
}
/**
* iavf_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 iavf_tx_enable_csum(struct sk_buff *skb, u32 *tx_flags,
u32 *td_cmd, u32 *td_offset,
struct iavf_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) << IAVF_TX_DESC_LENGTH_MACLEN_SHIFT;
if (skb->encapsulation) {
u32 tunnel = 0;
/* define outer network header type */
if (*tx_flags & IAVF_TX_FLAGS_IPV4) {
tunnel |= (*tx_flags & IAVF_TX_FLAGS_TSO) ?
IAVF_TX_CTX_EXT_IP_IPV4 :
IAVF_TX_CTX_EXT_IP_IPV4_NO_CSUM;
l4_proto = ip.v4->protocol;
} else if (*tx_flags & IAVF_TX_FLAGS_IPV6) {
tunnel |= IAVF_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 |= IAVF_TXD_CTX_UDP_TUNNELING;
*tx_flags |= IAVF_TX_FLAGS_VXLAN_TUNNEL;
break;
case IPPROTO_GRE:
tunnel |= IAVF_TXD_CTX_GRE_TUNNELING;
*tx_flags |= IAVF_TX_FLAGS_VXLAN_TUNNEL;
break;
case IPPROTO_IPIP:
case IPPROTO_IPV6:
*tx_flags |= IAVF_TX_FLAGS_VXLAN_TUNNEL;
l4.hdr = skb_inner_network_header(skb);
break;
default:
if (*tx_flags & IAVF_TX_FLAGS_TSO)
return -1;
skb_checksum_help(skb);
return 0;
}
/* compute outer L3 header size */
tunnel |= ((l4.hdr - ip.hdr) / 4) <<
IAVF_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) <<
IAVF_TXD_CTX_QW0_NATLEN_SHIFT;
/* indicate if we need to offload outer UDP header */
if ((*tx_flags & IAVF_TX_FLAGS_TSO) &&
!(skb_shinfo(skb)->gso_type & SKB_GSO_PARTIAL) &&
(skb_shinfo(skb)->gso_type & SKB_GSO_UDP_TUNNEL_CSUM))
tunnel |= IAVF_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 &= ~(IAVF_TX_FLAGS_IPV4 | IAVF_TX_FLAGS_IPV6);
if (ip.v4->version == 4)
*tx_flags |= IAVF_TX_FLAGS_IPV4;
if (ip.v6->version == 6)
*tx_flags |= IAVF_TX_FLAGS_IPV6;
}
/* Enable IP checksum offloads */
if (*tx_flags & IAVF_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 & IAVF_TX_FLAGS_TSO) ?
IAVF_TX_DESC_CMD_IIPT_IPV4_CSUM :
IAVF_TX_DESC_CMD_IIPT_IPV4;
} else if (*tx_flags & IAVF_TX_FLAGS_IPV6) {
cmd |= IAVF_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) << IAVF_TX_DESC_LENGTH_IPLEN_SHIFT;
/* Enable L4 checksum offloads */
switch (l4_proto) {
case IPPROTO_TCP:
/* enable checksum offloads */
cmd |= IAVF_TX_DESC_CMD_L4T_EOFT_TCP;
offset |= l4.tcp->doff << IAVF_TX_DESC_LENGTH_L4_FC_LEN_SHIFT;
break;
case IPPROTO_SCTP:
/* enable SCTP checksum offload */
cmd |= IAVF_TX_DESC_CMD_L4T_EOFT_SCTP;
offset |= (sizeof(struct sctphdr) >> 2) <<
IAVF_TX_DESC_LENGTH_L4_FC_LEN_SHIFT;
break;
case IPPROTO_UDP:
/* enable UDP checksum offload */
cmd |= IAVF_TX_DESC_CMD_L4T_EOFT_UDP;
offset |= (sizeof(struct udphdr) >> 2) <<
IAVF_TX_DESC_LENGTH_L4_FC_LEN_SHIFT;
break;
default:
if (*tx_flags & IAVF_TX_FLAGS_TSO)
return -1;
skb_checksum_help(skb);
return 0;
}
*td_cmd |= cmd;
*td_offset |= offset;
return 1;
}
/**
* iavf_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 iavf_create_tx_ctx(struct iavf_ring *tx_ring,
const u64 cd_type_cmd_tso_mss,
const u32 cd_tunneling, const u32 cd_l2tag2)
{
struct iavf_tx_context_desc *context_desc;
int i = tx_ring->next_to_use;
if ((cd_type_cmd_tso_mss == IAVF_TX_DESC_DTYPE_CONTEXT) &&
!cd_tunneling && !cd_l2tag2)
return;
/* grab the next descriptor */
context_desc = IAVF_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);
}
/**
* __iavf_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 __iavf_chk_linearize(struct sk_buff *skb)
{
const skb_frag_t *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 < (IAVF_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 -= IAVF_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 > IAVF_MAX_DATA_PER_TXD) {
int align_pad = -(skb_frag_off(stale)) &
(IAVF_MAX_READ_REQ_SIZE - 1);
sum -= align_pad;
stale_size -= align_pad;
do {
sum -= IAVF_MAX_DATA_PER_TXD_ALIGNED;
stale_size -= IAVF_MAX_DATA_PER_TXD_ALIGNED;
} while (stale_size > IAVF_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;
}
/**
* __iavf_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 __iavf_maybe_stop_tx(struct iavf_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(IAVF_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;
}
/**
* iavf_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 iavf_tx_map(struct iavf_ring *tx_ring, struct sk_buff *skb,
struct iavf_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);
skb_frag_t *frag;
struct iavf_tx_buffer *tx_bi;
struct iavf_tx_desc *tx_desc;
u16 i = tx_ring->next_to_use;
u32 td_tag = 0;
dma_addr_t dma;
if (tx_flags & IAVF_TX_FLAGS_HW_VLAN) {
td_cmd |= IAVF_TX_DESC_CMD_IL2TAG1;
td_tag = (tx_flags & IAVF_TX_FLAGS_VLAN_MASK) >>
IAVF_TX_FLAGS_VLAN_SHIFT;
}
first->tx_flags = tx_flags;
dma = dma_map_single(tx_ring->dev, skb->data, size, DMA_TO_DEVICE);
tx_desc = IAVF_TX_DESC(tx_ring, i);
tx_bi = first;
for (frag = &skb_shinfo(skb)->frags[0];; frag++) {
unsigned int max_data = IAVF_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 & (IAVF_MAX_READ_REQ_SIZE - 1);
tx_desc->buffer_addr = cpu_to_le64(dma);
while (unlikely(size > IAVF_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 = IAVF_TX_DESC(tx_ring, 0);
i = 0;
}
dma += max_data;
size -= max_data;
max_data = IAVF_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 = IAVF_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;
iavf_maybe_stop_tx(tx_ring, DESC_NEEDED);
/* write last descriptor with RS and EOP bits */
td_cmd |= IAVF_TXD_CMD;
tx_desc->cmd_type_offset_bsz =
build_ctob(td_cmd, td_offset, size, td_tag);
skb_tx_timestamp(skb);
/* 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)) || !netdev_xmit_more()) {
writel(i, tx_ring->tail);
}
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];
iavf_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;
}
/**
* iavf_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 iavf_xmit_frame_ring(struct sk_buff *skb,
struct iavf_ring *tx_ring)
{
u64 cd_type_cmd_tso_mss = IAVF_TX_DESC_DTYPE_CONTEXT;
u32 cd_tunneling = 0, cd_l2tag2 = 0;
struct iavf_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);
iavf_trace(xmit_frame_ring, skb, tx_ring);
count = iavf_xmit_descriptor_count(skb);
if (iavf_chk_linearize(skb, count)) {
if (__skb_linearize(skb)) {
dev_kfree_skb_any(skb);
return NETDEV_TX_OK;
}
count = iavf_txd_use_count(skb->len);
tx_ring->tx_stats.tx_linearize++;
}
/* need: 1 descriptor per page * PAGE_SIZE/IAVF_MAX_DATA_PER_TXD,
* + 1 desc for skb_head_len/IAVF_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 (iavf_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 (iavf_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 |= IAVF_TX_FLAGS_IPV4;
else if (protocol == htons(ETH_P_IPV6))
tx_flags |= IAVF_TX_FLAGS_IPV6;
tso = iavf_tso(first, &hdr_len, &cd_type_cmd_tso_mss);
if (tso < 0)
goto out_drop;
else if (tso)
tx_flags |= IAVF_TX_FLAGS_TSO;
/* Always offload the checksum, since it's in the data descriptor */
tso = iavf_tx_enable_csum(skb, &tx_flags, &td_cmd, &td_offset,
tx_ring, &cd_tunneling);
if (tso < 0)
goto out_drop;
/* always enable CRC insertion offload */
td_cmd |= IAVF_TX_DESC_CMD_ICRC;
iavf_create_tx_ctx(tx_ring, cd_type_cmd_tso_mss,
cd_tunneling, cd_l2tag2);
iavf_tx_map(tx_ring, skb, first, tx_flags, hdr_len,
td_cmd, td_offset);
return NETDEV_TX_OK;
out_drop:
iavf_trace(xmit_frame_ring_drop, first->skb, tx_ring);
dev_kfree_skb_any(first->skb);
first->skb = NULL;
return NETDEV_TX_OK;
}
/**
* iavf_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 iavf_xmit_frame(struct sk_buff *skb, struct net_device *netdev)
{
struct iavf_adapter *adapter = netdev_priv(netdev);
struct iavf_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 < IAVF_MIN_TX_LEN)) {
if (skb_pad(skb, IAVF_MIN_TX_LEN - skb->len))
return NETDEV_TX_OK;
skb->len = IAVF_MIN_TX_LEN;
skb_set_tail_pointer(skb, IAVF_MIN_TX_LEN);
}
return iavf_xmit_frame_ring(skb, tx_ring);
}