diff options
Diffstat (limited to 'drivers/net/ethernet/intel/ice/ice_txrx.c')
| -rw-r--r-- | drivers/net/ethernet/intel/ice/ice_txrx.c | 1782 |
1 files changed, 1782 insertions, 0 deletions
diff --git a/drivers/net/ethernet/intel/ice/ice_txrx.c b/drivers/net/ethernet/intel/ice/ice_txrx.c new file mode 100644 index 000000000000..6481e3d86374 --- /dev/null +++ b/drivers/net/ethernet/intel/ice/ice_txrx.c @@ -0,0 +1,1782 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Copyright (c) 2018, Intel Corporation. */ + +/* The driver transmit and receive code */ + +#include <linux/prefetch.h> +#include <linux/mm.h> +#include "ice.h" + +#define ICE_RX_HDR_SIZE 256 + +/** + * ice_unmap_and_free_tx_buf - Release a Tx buffer + * @ring: the ring that owns the buffer + * @tx_buf: the buffer to free + */ +static void +ice_unmap_and_free_tx_buf(struct ice_ring *ring, struct ice_tx_buf *tx_buf) +{ + if (tx_buf->skb) { + dev_kfree_skb_any(tx_buf->skb); + if (dma_unmap_len(tx_buf, len)) + dma_unmap_single(ring->dev, + dma_unmap_addr(tx_buf, dma), + dma_unmap_len(tx_buf, len), + DMA_TO_DEVICE); + } else if (dma_unmap_len(tx_buf, len)) { + dma_unmap_page(ring->dev, + dma_unmap_addr(tx_buf, dma), + dma_unmap_len(tx_buf, len), + DMA_TO_DEVICE); + } + + tx_buf->next_to_watch = NULL; + tx_buf->skb = NULL; + dma_unmap_len_set(tx_buf, len, 0); + /* tx_buf must be completely set up in the transmit path */ +} + +static struct netdev_queue *txring_txq(const struct ice_ring *ring) +{ + return netdev_get_tx_queue(ring->netdev, ring->q_index); +} + +/** + * ice_clean_tx_ring - Free any empty Tx buffers + * @tx_ring: ring to be cleaned + */ +void ice_clean_tx_ring(struct ice_ring *tx_ring) +{ + unsigned long size; + u16 i; + + /* ring already cleared, nothing to do */ + if (!tx_ring->tx_buf) + return; + + /* Free all the Tx ring sk_bufss */ + for (i = 0; i < tx_ring->count; i++) + ice_unmap_and_free_tx_buf(tx_ring, &tx_ring->tx_buf[i]); + + size = sizeof(struct ice_tx_buf) * tx_ring->count; + memset(tx_ring->tx_buf, 0, 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)); +} + +/** + * ice_free_tx_ring - Free Tx resources per queue + * @tx_ring: Tx descriptor ring for a specific queue + * + * Free all transmit software resources + */ +void ice_free_tx_ring(struct ice_ring *tx_ring) +{ + ice_clean_tx_ring(tx_ring); + devm_kfree(tx_ring->dev, tx_ring->tx_buf); + tx_ring->tx_buf = NULL; + + if (tx_ring->desc) { + dmam_free_coherent(tx_ring->dev, tx_ring->size, + tx_ring->desc, tx_ring->dma); + tx_ring->desc = NULL; + } +} + +/** + * ice_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 ice_clean_tx_irq(struct ice_vsi *vsi, struct ice_ring *tx_ring, + int napi_budget) +{ + unsigned int total_bytes = 0, total_pkts = 0; + unsigned int budget = vsi->work_lmt; + s16 i = tx_ring->next_to_clean; + struct ice_tx_desc *tx_desc; + struct ice_tx_buf *tx_buf; + + tx_buf = &tx_ring->tx_buf[i]; + tx_desc = ICE_TX_DESC(tx_ring, i); + i -= tx_ring->count; + + do { + struct ice_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; + + smp_rmb(); /* prevent any other reads prior to eop_desc */ + + /* if the descriptor isn't done, no work yet to do */ + if (!(eop_desc->cmd_type_offset_bsz & + cpu_to_le64(ICE_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_pkts += 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_buf data */ + tx_buf->skb = NULL; + dma_unmap_len_set(tx_buf, len, 0); + + /* unmap remaining buffers */ + while (tx_desc != eop_desc) { + tx_buf++; + tx_desc++; + i++; + if (unlikely(!i)) { + i -= tx_ring->count; + tx_buf = tx_ring->tx_buf; + tx_desc = ICE_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_buf; + tx_desc = ICE_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.pkts += total_pkts; + u64_stats_update_end(&tx_ring->syncp); + tx_ring->q_vector->tx.total_bytes += total_bytes; + tx_ring->q_vector->tx.total_pkts += total_pkts; + + netdev_tx_completed_queue(txring_txq(tx_ring), total_pkts, + total_bytes); + +#define TX_WAKE_THRESHOLD ((s16)(DESC_NEEDED * 2)) + if (unlikely(total_pkts && netif_carrier_ok(tx_ring->netdev) && + (ICE_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->q_index) && + !test_bit(__ICE_DOWN, vsi->state)) { + netif_wake_subqueue(tx_ring->netdev, + tx_ring->q_index); + ++tx_ring->tx_stats.restart_q; + } + } + + return !!budget; +} + +/** + * ice_setup_tx_ring - Allocate the Tx descriptors + * @tx_ring: the tx ring to set up + * + * Return 0 on success, negative on error + */ +int ice_setup_tx_ring(struct ice_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_buf); + bi_size = sizeof(struct ice_tx_buf) * tx_ring->count; + tx_ring->tx_buf = devm_kzalloc(dev, bi_size, GFP_KERNEL); + if (!tx_ring->tx_buf) + return -ENOMEM; + + /* round up to nearest 4K */ + tx_ring->size = tx_ring->count * sizeof(struct ice_tx_desc); + tx_ring->size = ALIGN(tx_ring->size, 4096); + tx_ring->desc = dmam_alloc_coherent(dev, tx_ring->size, &tx_ring->dma, + GFP_KERNEL); + if (!tx_ring->desc) { + dev_err(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; + return 0; + +err: + devm_kfree(dev, tx_ring->tx_buf); + tx_ring->tx_buf = NULL; + return -ENOMEM; +} + +/** + * ice_clean_rx_ring - Free Rx buffers + * @rx_ring: ring to be cleaned + */ +void ice_clean_rx_ring(struct ice_ring *rx_ring) +{ + struct device *dev = rx_ring->dev; + unsigned long size; + u16 i; + + /* ring already cleared, nothing to do */ + if (!rx_ring->rx_buf) + return; + + /* Free all the Rx ring sk_buffs */ + for (i = 0; i < rx_ring->count; i++) { + struct ice_rx_buf *rx_buf = &rx_ring->rx_buf[i]; + + if (rx_buf->skb) { + dev_kfree_skb(rx_buf->skb); + rx_buf->skb = NULL; + } + if (!rx_buf->page) + continue; + + dma_unmap_page(dev, rx_buf->dma, PAGE_SIZE, DMA_FROM_DEVICE); + __free_pages(rx_buf->page, 0); + + rx_buf->page = NULL; + rx_buf->page_offset = 0; + } + + size = sizeof(struct ice_rx_buf) * rx_ring->count; + memset(rx_ring->rx_buf, 0, 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; +} + +/** + * ice_free_rx_ring - Free Rx resources + * @rx_ring: ring to clean the resources from + * + * Free all receive software resources + */ +void ice_free_rx_ring(struct ice_ring *rx_ring) +{ + ice_clean_rx_ring(rx_ring); + devm_kfree(rx_ring->dev, rx_ring->rx_buf); + rx_ring->rx_buf = NULL; + + if (rx_ring->desc) { + dmam_free_coherent(rx_ring->dev, rx_ring->size, + rx_ring->desc, rx_ring->dma); + rx_ring->desc = NULL; + } +} + +/** + * ice_setup_rx_ring - Allocate the Rx descriptors + * @rx_ring: the rx ring to set up + * + * Return 0 on success, negative on error + */ +int ice_setup_rx_ring(struct ice_ring *rx_ring) +{ + struct device *dev = rx_ring->dev; + int bi_size; + + if (!dev) + return -ENOMEM; + + /* warn if we are about to overwrite the pointer */ + WARN_ON(rx_ring->rx_buf); + bi_size = sizeof(struct ice_rx_buf) * rx_ring->count; + rx_ring->rx_buf = devm_kzalloc(dev, bi_size, GFP_KERNEL); + if (!rx_ring->rx_buf) + return -ENOMEM; + + /* round up to nearest 4K */ + rx_ring->size = rx_ring->count * sizeof(union ice_32byte_rx_desc); + rx_ring->size = ALIGN(rx_ring->size, 4096); + rx_ring->desc = dmam_alloc_coherent(dev, rx_ring->size, &rx_ring->dma, + GFP_KERNEL); + if (!rx_ring->desc) { + dev_err(dev, "Unable to allocate memory for the Rx descriptor ring, size=%d\n", + rx_ring->size); + goto err; + } + + rx_ring->next_to_use = 0; + rx_ring->next_to_clean = 0; + return 0; + +err: + devm_kfree(dev, rx_ring->rx_buf); + rx_ring->rx_buf = NULL; + return -ENOMEM; +} + +/** + * ice_release_rx_desc - Store the new tail and head values + * @rx_ring: ring to bump + * @val: new head index + */ +static void ice_release_rx_desc(struct ice_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); +} + +/** + * ice_alloc_mapped_page - recycle or make a new page + * @rx_ring: ring to use + * @bi: rx_buf struct to modify + * + * Returns true if the page was successfully allocated or + * reused. + */ +static bool ice_alloc_mapped_page(struct ice_ring *rx_ring, + struct ice_rx_buf *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 = alloc_page(GFP_ATOMIC | __GFP_NOWARN); + if (unlikely(!page)) { + rx_ring->rx_stats.alloc_page_failed++; + return false; + } + + /* map page for use */ + dma = dma_map_page(rx_ring->dev, page, 0, PAGE_SIZE, DMA_FROM_DEVICE); + + /* 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, 0); + rx_ring->rx_stats.alloc_page_failed++; + return false; + } + + bi->dma = dma; + bi->page = page; + bi->page_offset = 0; + + return true; +} + +/** + * ice_alloc_rx_bufs - 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 ice_alloc_rx_bufs(struct ice_ring *rx_ring, u16 cleaned_count) +{ + union ice_32b_rx_flex_desc *rx_desc; + u16 ntu = rx_ring->next_to_use; + struct ice_rx_buf *bi; + + /* do nothing if no valid netdev defined */ + if (!rx_ring->netdev || !cleaned_count) + return false; + + /* get the RX descriptor and buffer based on next_to_use */ + rx_desc = ICE_RX_DESC(rx_ring, ntu); + bi = &rx_ring->rx_buf[ntu]; + + do { + if (!ice_alloc_mapped_page(rx_ring, bi)) + goto no_bufs; + + /* 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 = ICE_RX_DESC(rx_ring, 0); + bi = rx_ring->rx_buf; + ntu = 0; + } + + /* clear the status bits for the next_to_use descriptor */ + rx_desc->wb.status_error0 = 0; + + cleaned_count--; + } while (cleaned_count); + + if (rx_ring->next_to_use != ntu) + ice_release_rx_desc(rx_ring, ntu); + + return false; + +no_bufs: + if (rx_ring->next_to_use != ntu) + ice_release_rx_desc(rx_ring, ntu); + + /* make sure to come back via polling to try again after + * allocation failure + */ + return true; +} + +/** + * ice_page_is_reserved - check if reuse is possible + * @page: page struct to check + */ +static bool ice_page_is_reserved(struct page *page) +{ + return (page_to_nid(page) != numa_mem_id()) || page_is_pfmemalloc(page); +} + +/** + * ice_add_rx_frag - Add contents of Rx buffer to sk_buff + * @rx_buf: buffer containing page to add + * @rx_desc: descriptor containing length of buffer written by hardware + * @skb: sk_buf to place the data into + * + * This function will add the data contained in rx_buf->page to the skb. + * This is done either through a direct copy if the data in the buffer is + * less than the skb header size, otherwise it will just attach the page as + * a frag to the skb. + * + * The function will then update the page offset if necessary and return + * true if the buffer can be reused by the adapter. + */ +static bool ice_add_rx_frag(struct ice_rx_buf *rx_buf, + union ice_32b_rx_flex_desc *rx_desc, + struct sk_buff *skb) +{ +#if (PAGE_SIZE < 8192) + unsigned int truesize = ICE_RXBUF_2048; +#else + unsigned int last_offset = PAGE_SIZE - ICE_RXBUF_2048; + unsigned int truesize; +#endif /* PAGE_SIZE < 8192) */ + + struct page *page; + unsigned int size; + + size = le16_to_cpu(rx_desc->wb.pkt_len) & + ICE_RX_FLX_DESC_PKT_LEN_M; + + page = rx_buf->page; + +#if (PAGE_SIZE >= 8192) + truesize = ALIGN(size, L1_CACHE_BYTES); +#endif /* PAGE_SIZE >= 8192) */ + + /* will the data fit in the skb we allocated? if so, just + * copy it as it is pretty small anyway + */ + if (size <= ICE_RX_HDR_SIZE && !skb_is_nonlinear(skb)) { + unsigned char *va = page_address(page) + rx_buf->page_offset; + + memcpy(__skb_put(skb, size), va, ALIGN(size, sizeof(long))); + + /* page is not reserved, we can reuse buffer as-is */ + if (likely(!ice_page_is_reserved(page))) + return true; + + /* this page cannot be reused so discard it */ + __free_pages(page, 0); + return false; + } + + skb_add_rx_frag(skb, skb_shinfo(skb)->nr_frags, page, + rx_buf->page_offset, size, truesize); + + /* avoid re-using remote pages */ + if (unlikely(ice_page_is_reserved(page))) + return false; + +#if (PAGE_SIZE < 8192) + /* if we are only owner of page we can reuse it */ + if (unlikely(page_count(page) != 1)) + return false; + + /* flip page offset to other buffer */ + rx_buf->page_offset ^= truesize; +#else + /* move offset up to the next cache line */ + rx_buf->page_offset += truesize; + + if (rx_buf->page_offset > last_offset) + return false; +#endif /* PAGE_SIZE < 8192) */ + + /* Even if we own the page, we are not allowed to use atomic_set() + * This would break get_page_unless_zero() users. + */ + get_page(rx_buf->page); + + return true; +} + +/** + * ice_reuse_rx_page - page flip buffer and store it back on the ring + * @rx_ring: rx descriptor ring to store buffers on + * @old_buf: donor buffer to have page reused + * + * Synchronizes page for reuse by the adapter + */ +static void ice_reuse_rx_page(struct ice_ring *rx_ring, + struct ice_rx_buf *old_buf) +{ + u16 nta = rx_ring->next_to_alloc; + struct ice_rx_buf *new_buf; + + new_buf = &rx_ring->rx_buf[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_buf = *old_buf; +} + +/** + * ice_fetch_rx_buf - Allocate skb and populate it + * @rx_ring: rx descriptor ring to transact packets on + * @rx_desc: descriptor containing info written by hardware + * + * This function allocates an skb on the fly, and populates it with the page + * data from the current receive descriptor, taking care to set up the skb + * correctly, as well as handling calling the page recycle function if + * necessary. + */ +static struct sk_buff *ice_fetch_rx_buf(struct ice_ring *rx_ring, + union ice_32b_rx_flex_desc *rx_desc) +{ + struct ice_rx_buf *rx_buf; + struct sk_buff *skb; + struct page *page; + + rx_buf = &rx_ring->rx_buf[rx_ring->next_to_clean]; + page = rx_buf->page; + prefetchw(page); + + skb = rx_buf->skb; + + if (likely(!skb)) { + u8 *page_addr = page_address(page) + rx_buf->page_offset; + + /* prefetch first cache line of first page */ + prefetch(page_addr); +#if L1_CACHE_BYTES < 128 + prefetch((void *)(page_addr + L1_CACHE_BYTES)); +#endif /* L1_CACHE_BYTES */ + + /* allocate a skb to store the frags */ + skb = __napi_alloc_skb(&rx_ring->q_vector->napi, + ICE_RX_HDR_SIZE, + GFP_ATOMIC | __GFP_NOWARN); + if (unlikely(!skb)) { + rx_ring->rx_stats.alloc_buf_failed++; + return NULL; + } + + /* we will be copying header into skb->data in + * pskb_may_pull so it is in our interest to prefetch + * it now to avoid a possible cache miss + */ + prefetchw(skb->data); + + skb_record_rx_queue(skb, rx_ring->q_index); + } else { + /* we are reusing so sync this buffer for CPU use */ + dma_sync_single_range_for_cpu(rx_ring->dev, rx_buf->dma, + rx_buf->page_offset, + ICE_RXBUF_2048, + DMA_FROM_DEVICE); + + rx_buf->skb = NULL; + } + + /* pull page into skb */ + if (ice_add_rx_frag(rx_buf, rx_desc, skb)) { + /* hand second half of page back to the ring */ + ice_reuse_rx_page(rx_ring, rx_buf); + rx_ring->rx_stats.page_reuse_count++; + } else { + /* we are not reusing the buffer so unmap it */ + dma_unmap_page(rx_ring->dev, rx_buf->dma, PAGE_SIZE, + DMA_FROM_DEVICE); + } + + /* clear contents of buffer_info */ + rx_buf->page = NULL; + + return skb; +} + +/** + * ice_pull_tail - ice specific version of skb_pull_tail + * @skb: pointer to current skb being adjusted + * + * This function is an ice specific version of __pskb_pull_tail. The + * main difference between this version and the original function is that + * this function can make several assumptions about the state of things + * that allow for significant optimizations versus the standard function. + * As a result we can do things like drop a frag and maintain an accurate + * truesize for the skb. + */ +static void ice_pull_tail(struct sk_buff *skb) +{ + struct skb_frag_struct *frag = &skb_shinfo(skb)->frags[0]; + unsigned int pull_len; + unsigned char *va; + + /* it is valid to use page_address instead of kmap since we are + * working with pages allocated out of the lomem pool per + * alloc_page(GFP_ATOMIC) + */ + va = skb_frag_address(frag); + + /* we need the header to contain the greater of either ETH_HLEN or + * 60 bytes if the skb->len is less than 60 for skb_pad. + */ + pull_len = eth_get_headlen(va, ICE_RX_HDR_SIZE); + + /* align pull length to size of long to optimize memcpy performance */ + skb_copy_to_linear_data(skb, va, ALIGN(pull_len, sizeof(long))); + + /* update all of the pointers */ + skb_frag_size_sub(frag, pull_len); + frag->page_offset += pull_len; + skb->data_len -= pull_len; + skb->tail += pull_len; +} + +/** + * ice_cleanup_headers - Correct empty headers + * @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 ice_cleanup_headers(struct sk_buff *skb) +{ + /* place header in linear portion of buffer */ + if (skb_is_nonlinear(skb)) + ice_pull_tail(skb); + + /* if eth_skb_pad returns an error the skb was freed */ + if (eth_skb_pad(skb)) + return true; + + return false; +} + +/** + * ice_test_staterr - tests bits in Rx descriptor status and error fields + * @rx_desc: pointer to receive descriptor (in le64 format) + * @stat_err_bits: value to mask + * + * This function does some fast chicanery in order to return the + * value of the mask which is really only used for boolean tests. + * The status_error_len doesn't need to be shifted because it begins + * at offset zero. + */ +static bool ice_test_staterr(union ice_32b_rx_flex_desc *rx_desc, + const u16 stat_err_bits) +{ + return !!(rx_desc->wb.status_error0 & + cpu_to_le16(stat_err_bits)); +} + +/** + * ice_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 ice_is_non_eop(struct ice_ring *rx_ring, + union ice_32b_rx_flex_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(ICE_RX_DESC(rx_ring, ntc)); + + /* if we are the last buffer then there is nothing else to do */ +#define ICE_RXD_EOF BIT(ICE_RX_FLEX_DESC_STATUS0_EOF_S) + if (likely(ice_test_staterr(rx_desc, ICE_RXD_EOF))) + return false; + + /* place skb in next buffer to be received */ + rx_ring->rx_buf[ntc].skb = skb; + rx_ring->rx_stats.non_eop_descs++; + + return true; +} + +/** + * ice_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 enum pkt_hash_types ice_ptype_to_htype(u8 __always_unused ptype) +{ + return PKT_HASH_TYPE_NONE; +} + +/** + * ice_rx_hash - set the hash value in the skb + * @rx_ring: descriptor ring + * @rx_desc: specific descriptor + * @skb: pointer to current skb + * @rx_ptype: the ptype value from the descriptor + */ +static void +ice_rx_hash(struct ice_ring *rx_ring, union ice_32b_rx_flex_desc *rx_desc, + struct sk_buff *skb, u8 rx_ptype) +{ + struct ice_32b_rx_flex_desc_nic *nic_mdid; + u32 hash; + + if (!(rx_ring->netdev->features & NETIF_F_RXHASH)) + return; + + if (rx_desc->wb.rxdid != ICE_RXDID_FLEX_NIC) + return; + + nic_mdid = (struct ice_32b_rx_flex_desc_nic *)rx_desc; + hash = le32_to_cpu(nic_mdid->rss_hash); + skb_set_hash(skb, hash, ice_ptype_to_htype(rx_ptype)); +} + +/** + * ice_rx_csum - Indicate in skb if checksum is good + * @vsi: the VSI we care about + * @skb: skb currently being received and modified + * @rx_desc: the receive descriptor + * @ptype: the packet type decoded by hardware + * + * skb->protocol must be set before this function is called + */ +static void ice_rx_csum(struct ice_vsi *vsi, struct sk_buff *skb, + union ice_32b_rx_flex_desc *rx_desc, u8 ptype) +{ + struct ice_rx_ptype_decoded decoded; + u32 rx_error, rx_status; + bool ipv4, ipv6; + + rx_status = le16_to_cpu(rx_desc->wb.status_error0); + rx_error = rx_status; + + decoded = ice_decode_rx_desc_ptype(ptype); + + /* Start with CHECKSUM_NONE and by default csum_level = 0 */ + skb->ip_summed = CHECKSUM_NONE; + skb_checksum_none_assert(skb); + + /* check if Rx checksum is enabled */ + if (!(vsi->netdev->features & NETIF_F_RXCSUM)) + return; + + /* check if HW has decoded the packet and checksum */ + if (!(rx_status & BIT(ICE_RX_FLEX_DESC_STATUS0_L3L4P_S))) + return; + + if (!(decoded.known && decoded.outer_ip)) + return; + + ipv4 = (decoded.outer_ip == ICE_RX_PTYPE_OUTER_IP) && + (decoded.outer_ip_ver == ICE_RX_PTYPE_OUTER_IPV4); + ipv6 = (decoded.outer_ip == ICE_RX_PTYPE_OUTER_IP) && + (decoded.outer_ip_ver == ICE_RX_PTYPE_OUTER_IPV6); + + if (ipv4 && (rx_error & (BIT(ICE_RX_FLEX_DESC_STATUS0_XSUM_IPE_S) | + BIT(ICE_RX_FLEX_DESC_STATUS0_XSUM_EIPE_S)))) + goto checksum_fail; + else if (ipv6 && (rx_status & + (BIT(ICE_RX_FLEX_DESC_STATUS0_IPV6EXADD_S)))) + goto checksum_fail; + + /* check for L4 errors and handle packets that were not able to be + * checksummed due to arrival speed + */ + if (rx_error & BIT(ICE_RX_FLEX_DESC_STATUS0_XSUM_L4E_S)) + goto checksum_fail; + + /* Only report checksum unnecessary for TCP, UDP, or SCTP */ + switch (decoded.inner_prot) { + case ICE_RX_PTYPE_INNER_PROT_TCP: + case ICE_RX_PTYPE_INNER_PROT_UDP: + case ICE_RX_PTYPE_INNER_PROT_SCTP: + skb->ip_summed = CHECKSUM_UNNECESSARY; + default: + break; + } + return; + +checksum_fail: + vsi->back->hw_csum_rx_error++; +} + +/** + * ice_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 + * @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 void ice_process_skb_fields(struct ice_ring *rx_ring, + union ice_32b_rx_flex_desc *rx_desc, + struct sk_buff *skb, u8 ptype) +{ + ice_rx_hash(rx_ring, rx_desc, skb, ptype); + + /* modifies the skb - consumes the enet header */ + skb->protocol = eth_type_trans(skb, rx_ring->netdev); + + ice_rx_csum(rx_ring->vsi, skb, rx_desc, ptype); +} + +/** + * ice_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 + * + * This function sends the completed packet (via. skb) up the stack using + * gro receive functions (with/without vlan tag) + */ +static void ice_receive_skb(struct ice_ring *rx_ring, struct sk_buff *skb, + u16 vlan_tag) +{ + 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(&rx_ring->q_vector->napi, skb); +} + +/** + * ice_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 ice_clean_rx_irq(struct ice_ring *rx_ring, int budget) +{ + unsigned int total_rx_bytes = 0, total_rx_pkts = 0; + u16 cleaned_count = ICE_DESC_UNUSED(rx_ring); + bool failure = false; + + /* start the loop to process RX packets bounded by 'budget' */ + while (likely(total_rx_pkts < (unsigned int)budget)) { + union ice_32b_rx_flex_desc *rx_desc; + struct sk_buff *skb; + u16 stat_err_bits; + u16 vlan_tag = 0; + u8 rx_ptype; + + /* return some buffers to hardware, one at a time is too slow */ + if (cleaned_count >= ICE_RX_BUF_WRITE) { + failure = failure || + ice_alloc_rx_bufs(rx_ring, cleaned_count); + cleaned_count = 0; + } + + /* get the RX desc from RX ring based on 'next_to_clean' */ + rx_desc = ICE_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 it will be non-zero + */ + stat_err_bits = BIT(ICE_RX_FLEX_DESC_STATUS0_DD_S); + if (!ice_test_staterr(rx_desc, stat_err_bits)) + break; + + /* This memory barrier is needed to keep us from reading + * any other fields out of the rx_desc until we know the + * DD bit is set. + */ + dma_rmb(); + + /* allocate (if needed) and populate skb */ + skb = ice_fetch_rx_buf(rx_ring, rx_desc); + if (!skb) + break; + + cleaned_count++; + + /* skip if it is NOP desc */ + if (ice_is_non_eop(rx_ring, rx_desc, skb)) + continue; + + stat_err_bits = BIT(ICE_RX_FLEX_DESC_STATUS0_RXE_S); + if (unlikely(ice_test_staterr(rx_desc, stat_err_bits))) { + dev_kfree_skb_any(skb); + continue; + } + + rx_ptype = le16_to_cpu(rx_desc->wb.ptype_flex_flags0) & + ICE_RX_FLEX_DESC_PTYPE_M; + + stat_err_bits = BIT(ICE_RX_FLEX_DESC_STATUS0_L2TAG1P_S); + if (ice_test_staterr(rx_desc, stat_err_bits)) + vlan_tag = le16_to_cpu(rx_desc->wb.l2tag1); + + /* correct empty headers and pad skb if needed (to make valid + * ethernet frame + */ + if (ice_cleanup_headers(skb)) { + skb = NULL; + continue; + } + + /* probably a little skewed due to removing CRC */ + total_rx_bytes += skb->len; + + /* populate checksum, VLAN, and protocol */ + ice_process_skb_fields(rx_ring, rx_desc, skb, rx_ptype); + + /* send completed skb up the stack */ + ice_receive_skb(rx_ring, skb, vlan_tag); + + /* update budget accounting */ + total_rx_pkts++; + } + + /* update queue and vector specific stats */ + u64_stats_update_begin(&rx_ring->syncp); + rx_ring->stats.pkts += total_rx_pkts; + rx_ring->stats.bytes += total_rx_bytes; + u64_stats_update_end(&rx_ring->syncp); + rx_ring->q_vector->rx.total_pkts += total_rx_pkts; + 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_pkts; +} + +/** + * ice_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 ice_napi_poll(struct napi_struct *napi, int budget) +{ + struct ice_q_vector *q_vector = + container_of(napi, struct ice_q_vector, napi); + struct ice_vsi *vsi = q_vector->vsi; + struct ice_pf *pf = vsi->back; + bool clean_complete = true; + int budget_per_ring = 0; + struct ice_ring *ring; + int work_done = 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. + */ + ice_for_each_ring(ring, q_vector->tx) + if (!ice_clean_tx_irq(vsi, ring, budget)) + clean_complete = false; + + /* Handle case where we are called by netpoll with a budget of 0 */ + if (budget <= 0) + return budget; + + /* 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. + */ + if (q_vector->num_ring_rx) + budget_per_ring = max(budget / q_vector->num_ring_rx, 1); + + ice_for_each_ring(ring, q_vector->rx) { + int cleaned; + + cleaned = ice_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) + return budget; + + /* Work is done so exit the polling mode and re-enable the interrupt */ + napi_complete_done(napi, work_done); + if (test_bit(ICE_FLAG_MSIX_ENA, pf->flags)) + ice_irq_dynamic_ena(&vsi->back->hw, vsi, q_vector); + return 0; +} + +/* helper function for building cmd/type/offset */ +static __le64 +build_ctob(u64 td_cmd, u64 td_offset, unsigned int size, u64 td_tag) +{ + return cpu_to_le64(ICE_TX_DESC_DTYPE_DATA | + (td_cmd << ICE_TXD_QW1_CMD_S) | + (td_offset << ICE_TXD_QW1_OFFSET_S) | + ((u64)size << ICE_TXD_QW1_TX_BUF_SZ_S) | + (td_tag << ICE_TXD_QW1_L2TAG1_S)); +} + +/** + * __ice_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 + */ +static int __ice_maybe_stop_tx(struct ice_ring *tx_ring, unsigned int size) +{ + netif_stop_subqueue(tx_ring->netdev, tx_ring->q_index); + /* Memory barrier before checking head and tail */ + smp_mb(); + + /* Check again in a case another CPU has just made room available. */ + if (likely(ICE_DESC_UNUSED(tx_ring) < size)) + return -EBUSY; + + /* A reprieve! - use start_subqueue because it doesn't call schedule */ + netif_start_subqueue(tx_ring->netdev, tx_ring->q_index); + ++tx_ring->tx_stats.restart_q; + return 0; +} + +/** + * ice_maybe_stop_tx - 1st level check for tx stop conditions + * @tx_ring: the ring to be checked + * @size: the size buffer we want to assure is available + * + * Returns 0 if stop is not needed + */ +static int ice_maybe_stop_tx(struct ice_ring *tx_ring, unsigned int size) +{ + if (likely(ICE_DESC_UNUSED(tx_ring) >= size)) + return 0; + return __ice_maybe_stop_tx(tx_ring, size); +} + +/** + * ice_tx_map - Build the Tx descriptor + * @tx_ring: ring to send buffer on + * @first: first buffer info buffer to use + * @off: pointer to struct that holds offload parameters + * + * This function loops over the skb data pointed to by *first + * and gets a physical address for each memory location and programs + * it and the length into the transmit descriptor. + */ +static void +ice_tx_map(struct ice_ring *tx_ring, struct ice_tx_buf *first, + struct ice_tx_offload_params *off) +{ + u64 td_offset, td_tag, td_cmd; + u16 i = tx_ring->next_to_use; + struct skb_frag_struct *frag; + unsigned int data_len, size; + struct ice_tx_desc *tx_desc; + struct ice_tx_buf *tx_buf; + struct sk_buff *skb; + dma_addr_t dma; + + td_tag = off->td_l2tag1; + td_cmd = off->td_cmd; + td_offset = off->td_offset; + skb = first->skb; + + data_len = skb->data_len; + size = skb_headlen(skb); + + tx_desc = ICE_TX_DESC(tx_ring, i); + + if (first->tx_flags & ICE_TX_FLAGS_HW_VLAN) { + td_cmd |= (u64)ICE_TX_DESC_CMD_IL2TAG1; + td_tag = (first->tx_flags & ICE_TX_FLAGS_VLAN_M) >> + ICE_TX_FLAGS_VLAN_S; + } + + dma = dma_map_single(tx_ring->dev, skb->data, size, DMA_TO_DEVICE); + + tx_buf = first; + + for (frag = &skb_shinfo(skb)->frags[0];; frag++) { + unsigned int max_data = ICE_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_buf, len, size); + dma_unmap_addr_set(tx_buf, dma, dma); + + /* align size to end of page */ + max_data += -dma & (ICE_MAX_READ_REQ_SIZE - 1); + tx_desc->buf_addr = cpu_to_le64(dma); + + /* account for data chunks larger than the hardware + * can handle + */ + while (unlikely(size > ICE_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 = ICE_TX_DESC(tx_ring, 0); + i = 0; + } + + dma += max_data; + size -= max_data; + + max_data = ICE_MAX_DATA_PER_TXD_ALIGNED; + tx_desc->buf_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 = ICE_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_buf = &tx_ring->tx_buf[i]; + } + + /* record bytecount for BQL */ + netdev_tx_sent_queue(txring_txq(tx_ring), first->bytecount); + + /* record SW timestamp if HW timestamp is not available */ + skb_tx_timestamp(first->skb); + + i++; + if (i == tx_ring->count) + i = 0; + + /* write last descriptor with RS and EOP bits */ + td_cmd |= (u64)(ICE_TX_DESC_CMD_EOP | ICE_TX_DESC_CMD_RS); + 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; + + tx_ring->next_to_use = i; + + ice_maybe_stop_tx(tx_ring, DESC_NEEDED); + + /* 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: + /* clear dma mappings for failed tx_buf map */ + for (;;) { + tx_buf = &tx_ring->tx_buf[i]; + ice_unmap_and_free_tx_buf(tx_ring, tx_buf); + if (tx_buf == first) + break; + if (i == 0) + i = tx_ring->count; + i--; + } + + tx_ring->next_to_use = i; +} + +/** + * ice_tx_csum - Enable Tx checksum offloads + * @first: pointer to the first descriptor + * @off: pointer to struct that holds offload parameters + * + * Returns 0 or error (negative) if checksum offload can't happen, 1 otherwise. + */ +static +int ice_tx_csum(struct ice_tx_buf *first, struct ice_tx_offload_params *off) +{ + u32 l4_len = 0, l3_len = 0, l2_len = 0; + struct sk_buff *skb = first->skb; + union { + struct iphdr *v4; + struct ipv6hdr *v6; + unsigned char *hdr; + } ip; + union { + struct tcphdr *tcp; + unsigned char *hdr; + } l4; + __be16 frag_off, protocol; + unsigned char *exthdr; + u32 offset, cmd = 0; + 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 */ + l2_len = ip.hdr - skb->data; + offset = (l2_len / 2) << ICE_TX_DESC_LEN_MACLEN_S; + + if (skb->encapsulation) + return -1; + + /* Enable IP checksum offloads */ + protocol = vlan_get_protocol(skb); + if (protocol == htons(ETH_P_IP)) { + 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. + */ + if (first->tx_flags & ICE_TX_FLAGS_TSO) + cmd |= ICE_TX_DESC_CMD_IIPT_IPV4_CSUM; + else + cmd |= ICE_TX_DESC_CMD_IIPT_IPV4; + + } else if (protocol == htons(ETH_P_IPV6)) { + cmd |= ICE_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); + } else { + return -1; + } + + /* compute inner L3 header size */ + l3_len = l4.hdr - ip.hdr; + offset |= (l3_len / 4) << ICE_TX_DESC_LEN_IPLEN_S; + + /* Enable L4 checksum offloads */ + switch (l4_proto) { + case IPPROTO_TCP: + /* enable checksum offloads */ + cmd |= ICE_TX_DESC_CMD_L4T_EOFT_TCP; + l4_len = l4.tcp->doff; + offset |= l4_len << ICE_TX_DESC_LEN_L4_LEN_S; + break; + case IPPROTO_UDP: + /* enable UDP checksum offload */ + cmd |= ICE_TX_DESC_CMD_L4T_EOFT_UDP; + l4_len = (sizeof(struct udphdr) >> 2); + offset |= l4_len << ICE_TX_DESC_LEN_L4_LEN_S; + break; + case IPPROTO_SCTP: + default: + if (first->tx_flags & ICE_TX_FLAGS_TSO) + return -1; + skb_checksum_help(skb); + return 0; + } + + off->td_cmd |= cmd; + off->td_offset |= offset; + return 1; +} + +/** + * ice_tx_prepare_vlan_flags - prepare generic TX VLAN tagging flags for HW + * @tx_ring: ring to send buffer on + * @first: pointer to struct ice_tx_buf + * + * 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 int +ice_tx_prepare_vlan_flags(struct ice_ring *tx_ring, struct ice_tx_buf *first) +{ + struct sk_buff *skb = first->skb; + __be16 protocol = skb->protocol; + + 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)) { + first->tx_flags |= skb_vlan_tag_get(skb) << ICE_TX_FLAGS_VLAN_S; + first->tx_flags |= ICE_TX_FLAGS_HW_VLAN; + } else if (protocol == htons(ETH_P_8021Q)) { + struct vlan_hdr *vhdr, _vhdr; + + /* for SW VLAN, check the next protocol and store the tag */ + vhdr = (struct vlan_hdr *)skb_header_pointer(skb, ETH_HLEN, + sizeof(_vhdr), + &_vhdr); + if (!vhdr) + return -EINVAL; + + first->tx_flags |= ntohs(vhdr->h_vlan_TCI) << + ICE_TX_FLAGS_VLAN_S; + first->tx_flags |= ICE_TX_FLAGS_SW_VLAN; + } + +out: + return 0; +} + +/** + * ice_tso - computes mss and TSO length to prepare for TSO + * @first: pointer to struct ice_tx_buf + * @off: pointer to struct that holds offload parameters + * + * Returns 0 or error (negative) if TSO can't happen, 1 otherwise. + */ +static +int ice_tso(struct ice_tx_buf *first, struct ice_tx_offload_params *off) +{ + struct sk_buff *skb = first->skb; + union { + struct iphdr *v4; + struct ipv6hdr *v6; + unsigned char *hdr; + } ip; + union { + struct tcphdr *tcp; + unsigned char *hdr; + } l4; + u64 cd_mss, cd_tso_len; + u32 paylen, l4_start; + 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; + } + + /* determine offset of transport header */ + l4_start = l4.hdr - skb->data; + + /* remove payload length from checksum */ + paylen = skb->len - l4_start; + csum_replace_by_diff(&l4.tcp->check, (__force __wsum)htonl(paylen)); + + /* compute length of segmentation header */ + off->header_len = (l4.tcp->doff * 4) + l4_start; + + /* update gso_segs and bytecount */ + first->gso_segs = skb_shinfo(skb)->gso_segs; + first->bytecount = (first->gso_segs - 1) * off->header_len; + + cd_tso_len = skb->len - off->header_len; + cd_mss = skb_shinfo(skb)->gso_size; + + /* record cdesc_qw1 with TSO parameters */ + off->cd_qw1 |= ICE_TX_DESC_DTYPE_CTX | + (ICE_TX_CTX_DESC_TSO << ICE_TXD_CTX_QW1_CMD_S) | + (cd_tso_len << ICE_TXD_CTX_QW1_TSO_LEN_S) | + (cd_mss << ICE_TXD_CTX_QW1_MSS_S); + first->tx_flags |= ICE_TX_FLAGS_TSO; + return 1; +} + +/** + * ice_txd_use_count - estimate the number of descriptors needed for Tx + * @size: transmit request size in bytes + * + * Due to hardware alignment restrictions (4K alignment), we need to + * assume that we can have no more than 12K of data per descriptor, even + * though each descriptor can take up to 16K - 1 bytes of aligned memory. + * Thus, we need to divide by 12K. But division is slow! Instead, + * we decompose the operation into shifts and one relatively cheap + * multiply operation. + * + * To divide by 12K, we first divide by 4K, then divide by 3: + * To divide by 4K, shift right by 12 bits + * To divide by 3, multiply by 85, then divide by 256 + * (Divide by 256 is done by shifting right by 8 bits) + * Finally, we add one to round up. Because 256 isn't an exact multiple of + * 3, we'll underestimate near each multiple of 12K. This is actually more + * accurate as we have 4K - 1 of wiggle room that we can fit into the last + * segment. For our purposes this is accurate out to 1M which is orders of + * magnitude greater than our largest possible GSO size. + * + * This would then be implemented as: + * return (((size >> 12) * 85) >> 8) + 1; + * + * Since multiplication and division are commutative, we can reorder + * operations into: + * return ((size * 85) >> 20) + 1; + */ +static unsigned int ice_txd_use_count(unsigned int size) +{ + return ((size * 85) >> 20) + 1; +} + +/** + * ice_xmit_desc_count - calculate number of tx descriptors needed + * @skb: send buffer + * + * Returns number of data descriptors needed for this skb. + */ +static unsigned int ice_xmit_desc_count(struct sk_buff *skb) +{ + const struct skb_frag_struct *frag = &skb_shinfo(skb)->frags[0]; + unsigned int nr_frags = skb_shinfo(skb)->nr_frags; + unsigned int count = 0, size = skb_headlen(skb); + + for (;;) { + count += ice_txd_use_count(size); + + if (!nr_frags--) + break; + + size = skb_frag_size(frag++); + } + + return count; +} + +/** + * __ice_chk_linearize - Check if there are more than 8 buffers per packet + * @skb: send buffer + * + * Note: This 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. + */ +static bool __ice_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 < (ICE_MAX_BUF_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 -= ICE_MAX_BUF_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. + */ + stale = &skb_shinfo(skb)->frags[0]; + for (;;) { + sum += skb_frag_size(frag++); + + /* if sum is negative we failed to make sufficient progress */ + if (sum < 0) + return true; + + if (!nr_frags--) + break; + + sum -= skb_frag_size(stale++); + } + + return false; +} + +/** + * ice_chk_linearize - Check if there are more than 8 fragments per packet + * @skb: send buffer + * @count: number of buffers used + * + * Note: Our HW can't scatter-gather more than 8 fragments to build + * a packet on the wire and so we need to figure out the cases where we + * need to linearize the skb. + */ +static bool ice_chk_linearize(struct sk_buff *skb, unsigned int count) +{ + /* Both TSO and single send will work if count is less than 8 */ + if (likely(count < ICE_MAX_BUF_TXD)) + return false; + + if (skb_is_gso(skb)) + return __ice_chk_linearize(skb); + + /* we can support up to 8 data buffers for a single send */ + return count != ICE_MAX_BUF_TXD; +} + +/** + * ice_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 +ice_xmit_frame_ring(struct sk_buff *skb, struct ice_ring *tx_ring) +{ + struct ice_tx_offload_params offload = { 0 }; + struct ice_tx_buf *first; + unsigned int count; + int tso, csum; + + count = ice_xmit_desc_count(skb); + if (ice_chk_linearize(skb, count)) { + if (__skb_linearize(skb)) + goto out_drop; + count = ice_txd_use_count(skb->len); + tx_ring->tx_stats.tx_linearize++; + } + + /* need: 1 descriptor per page * PAGE_SIZE/ICE_MAX_DATA_PER_TXD, + * + 1 desc for skb_head_len/ICE_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 (ice_maybe_stop_tx(tx_ring, count + 4 + 1)) { + tx_ring->tx_stats.tx_busy++; + return NETDEV_TX_BUSY; + } + + offload.tx_ring = tx_ring; + + /* record the location of the first descriptor for this packet */ + first = &tx_ring->tx_buf[tx_ring->next_to_use]; + first->skb = skb; + first->bytecount = max_t(unsigned int, skb->len, ETH_ZLEN); + first->gso_segs = 1; + first->tx_flags = 0; + + /* prepare the VLAN tagging flags for Tx */ + if (ice_tx_prepare_vlan_flags(tx_ring, first)) + goto out_drop; + + /* set up TSO offload */ + tso = ice_tso(first, &offload); + if (tso < 0) + goto out_drop; + + /* always set up Tx checksum offload */ + csum = ice_tx_csum(first, &offload); + if (csum < 0) + goto out_drop; + + if (tso || offload.cd_tunnel_params) { + struct ice_tx_ctx_desc *cdesc; + int i = tx_ring->next_to_use; + + /* grab the next descriptor */ + cdesc = ICE_TX_CTX_DESC(tx_ring, i); + i++; + tx_ring->next_to_use = (i < tx_ring->count) ? i : 0; + + /* setup context descriptor */ + cdesc->tunneling_params = cpu_to_le32(offload.cd_tunnel_params); + cdesc->l2tag2 = cpu_to_le16(offload.cd_l2tag2); + cdesc->rsvd = cpu_to_le16(0); + cdesc->qw1 = cpu_to_le64(offload.cd_qw1); + } + + ice_tx_map(tx_ring, first, &offload); + return NETDEV_TX_OK; + +out_drop: + dev_kfree_skb_any(skb); + return NETDEV_TX_OK; +} + +/** + * ice_start_xmit - 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 ice_start_xmit(struct sk_buff *skb, struct net_device *netdev) +{ + struct ice_netdev_priv *np = netdev_priv(netdev); + struct ice_vsi *vsi = np->vsi; + struct ice_ring *tx_ring; + + tx_ring = vsi->tx_rings[skb->queue_mapping]; + + /* hardware can't handle really short frames, hardware padding works + * beyond this point + */ + if (skb_put_padto(skb, ICE_MIN_TX_LEN)) + return NETDEV_TX_OK; + + return ice_xmit_frame_ring(skb, tx_ring); +} |