1 /****************************************************************************
2 * Driver for Solarflare Solarstorm network controllers and boards
3 * Copyright 2005-2006 Fen Systems Ltd.
4 * Copyright 2005-2009 Solarflare Communications Inc.
6 * This program is free software; you can redistribute it and/or modify it
7 * under the terms of the GNU General Public License version 2 as published
8 * by the Free Software Foundation, incorporated herein by reference.
11 #include <linux/pci.h>
12 #include <linux/tcp.h>
15 #include <linux/ipv6.h>
16 #include <linux/slab.h>
18 #include <linux/if_ether.h>
19 #include <linux/highmem.h>
20 #include "net_driver.h"
23 #include "workarounds.h"
26 * TX descriptor ring full threshold
28 * The tx_queue descriptor ring fill-level must fall below this value
29 * before we restart the netif queue
31 #define EFX_TXQ_THRESHOLD (EFX_TXQ_MASK / 2u)
33 /* We want to be able to nest calls to netif_stop_queue(), since each
34 * channel can have an individual stop on the queue.
36 void efx_stop_queue(struct efx_nic *efx)
38 spin_lock_bh(&efx->netif_stop_lock);
39 EFX_TRACE(efx, "stop TX queue\n");
41 atomic_inc(&efx->netif_stop_count);
42 netif_stop_queue(efx->net_dev);
44 spin_unlock_bh(&efx->netif_stop_lock);
47 /* Wake netif's TX queue
48 * We want to be able to nest calls to netif_stop_queue(), since each
49 * channel can have an individual stop on the queue.
51 void efx_wake_queue(struct efx_nic *efx)
54 if (atomic_dec_and_lock(&efx->netif_stop_count,
55 &efx->netif_stop_lock)) {
56 EFX_TRACE(efx, "waking TX queue\n");
57 netif_wake_queue(efx->net_dev);
58 spin_unlock(&efx->netif_stop_lock);
63 static void efx_dequeue_buffer(struct efx_tx_queue *tx_queue,
64 struct efx_tx_buffer *buffer)
66 if (buffer->unmap_len) {
67 struct pci_dev *pci_dev = tx_queue->efx->pci_dev;
68 dma_addr_t unmap_addr = (buffer->dma_addr + buffer->len -
70 if (buffer->unmap_single)
71 pci_unmap_single(pci_dev, unmap_addr, buffer->unmap_len,
74 pci_unmap_page(pci_dev, unmap_addr, buffer->unmap_len,
76 buffer->unmap_len = 0;
77 buffer->unmap_single = false;
81 dev_kfree_skb_any((struct sk_buff *) buffer->skb);
83 EFX_TRACE(tx_queue->efx, "TX queue %d transmission id %x "
84 "complete\n", tx_queue->queue, read_ptr);
89 * struct efx_tso_header - a DMA mapped buffer for packet headers
90 * @next: Linked list of free ones.
91 * The list is protected by the TX queue lock.
92 * @dma_unmap_len: Length to unmap for an oversize buffer, or 0.
93 * @dma_addr: The DMA address of the header below.
95 * This controls the memory used for a TSO header. Use TSOH_DATA()
96 * to find the packet header data. Use TSOH_SIZE() to calculate the
97 * total size required for a given packet header length. TSO headers
98 * in the free list are exactly %TSOH_STD_SIZE bytes in size.
100 struct efx_tso_header {
102 struct efx_tso_header *next;
108 static int efx_enqueue_skb_tso(struct efx_tx_queue *tx_queue,
109 struct sk_buff *skb);
110 static void efx_fini_tso(struct efx_tx_queue *tx_queue);
111 static void efx_tsoh_heap_free(struct efx_tx_queue *tx_queue,
112 struct efx_tso_header *tsoh);
114 static void efx_tsoh_free(struct efx_tx_queue *tx_queue,
115 struct efx_tx_buffer *buffer)
118 if (likely(!buffer->tsoh->unmap_len)) {
119 buffer->tsoh->next = tx_queue->tso_headers_free;
120 tx_queue->tso_headers_free = buffer->tsoh;
122 efx_tsoh_heap_free(tx_queue, buffer->tsoh);
129 static inline unsigned
130 efx_max_tx_len(struct efx_nic *efx, dma_addr_t dma_addr)
132 /* Depending on the NIC revision, we can use descriptor
133 * lengths up to 8K or 8K-1. However, since PCI Express
134 * devices must split read requests at 4K boundaries, there is
135 * little benefit from using descriptors that cross those
136 * boundaries and we keep things simple by not doing so.
138 unsigned len = (~dma_addr & 0xfff) + 1;
140 /* Work around hardware bug for unaligned buffers. */
141 if (EFX_WORKAROUND_5391(efx) && (dma_addr & 0xf))
142 len = min_t(unsigned, len, 512 - (dma_addr & 0xf));
148 * Add a socket buffer to a TX queue
150 * This maps all fragments of a socket buffer for DMA and adds them to
151 * the TX queue. The queue's insert pointer will be incremented by
152 * the number of fragments in the socket buffer.
154 * If any DMA mapping fails, any mapped fragments will be unmapped,
155 * the queue's insert pointer will be restored to its original value.
157 * This function is split out from efx_hard_start_xmit to allow the
158 * loopback test to direct packets via specific TX queues.
160 * Returns NETDEV_TX_OK or NETDEV_TX_BUSY
161 * You must hold netif_tx_lock() to call this function.
163 netdev_tx_t efx_enqueue_skb(struct efx_tx_queue *tx_queue, struct sk_buff *skb)
165 struct efx_nic *efx = tx_queue->efx;
166 struct pci_dev *pci_dev = efx->pci_dev;
167 struct efx_tx_buffer *buffer;
168 skb_frag_t *fragment;
171 unsigned int len, unmap_len = 0, fill_level, insert_ptr;
172 dma_addr_t dma_addr, unmap_addr = 0;
173 unsigned int dma_len;
176 netdev_tx_t rc = NETDEV_TX_OK;
178 EFX_BUG_ON_PARANOID(tx_queue->write_count != tx_queue->insert_count);
180 if (skb_shinfo(skb)->gso_size)
181 return efx_enqueue_skb_tso(tx_queue, skb);
183 /* Get size of the initial fragment */
184 len = skb_headlen(skb);
186 /* Pad if necessary */
187 if (EFX_WORKAROUND_15592(efx) && skb->len <= 32) {
188 EFX_BUG_ON_PARANOID(skb->data_len);
190 if (skb_pad(skb, len - skb->len))
194 fill_level = tx_queue->insert_count - tx_queue->old_read_count;
195 q_space = EFX_TXQ_MASK - 1 - fill_level;
197 /* Map for DMA. Use pci_map_single rather than pci_map_page
198 * since this is more efficient on machines with sparse
202 dma_addr = pci_map_single(pci_dev, skb->data, len, PCI_DMA_TODEVICE);
204 /* Process all fragments */
206 if (unlikely(pci_dma_mapping_error(pci_dev, dma_addr)))
209 /* Store fields for marking in the per-fragment final
212 unmap_addr = dma_addr;
214 /* Add to TX queue, splitting across DMA boundaries */
216 if (unlikely(q_space-- <= 0)) {
217 /* It might be that completions have
218 * happened since the xmit path last
219 * checked. Update the xmit path's
220 * copy of read_count.
223 /* This memory barrier protects the
224 * change of stopped from the access
227 tx_queue->old_read_count =
228 *(volatile unsigned *)
229 &tx_queue->read_count;
230 fill_level = (tx_queue->insert_count
231 - tx_queue->old_read_count);
232 q_space = EFX_TXQ_MASK - 1 - fill_level;
233 if (unlikely(q_space-- <= 0))
239 insert_ptr = tx_queue->insert_count & EFX_TXQ_MASK;
240 buffer = &tx_queue->buffer[insert_ptr];
241 efx_tsoh_free(tx_queue, buffer);
242 EFX_BUG_ON_PARANOID(buffer->tsoh);
243 EFX_BUG_ON_PARANOID(buffer->skb);
244 EFX_BUG_ON_PARANOID(buffer->len);
245 EFX_BUG_ON_PARANOID(!buffer->continuation);
246 EFX_BUG_ON_PARANOID(buffer->unmap_len);
248 dma_len = efx_max_tx_len(efx, dma_addr);
249 if (likely(dma_len >= len))
252 /* Fill out per descriptor fields */
253 buffer->len = dma_len;
254 buffer->dma_addr = dma_addr;
257 ++tx_queue->insert_count;
260 /* Transfer ownership of the unmapping to the final buffer */
261 buffer->unmap_single = unmap_single;
262 buffer->unmap_len = unmap_len;
265 /* Get address and size of next fragment */
266 if (i >= skb_shinfo(skb)->nr_frags)
268 fragment = &skb_shinfo(skb)->frags[i];
269 len = fragment->size;
270 page = fragment->page;
271 page_offset = fragment->page_offset;
274 unmap_single = false;
275 dma_addr = pci_map_page(pci_dev, page, page_offset, len,
279 /* Transfer ownership of the skb to the final buffer */
281 buffer->continuation = false;
283 /* Pass off to hardware */
284 efx_nic_push_buffers(tx_queue);
289 EFX_ERR_RL(efx, " TX queue %d could not map skb with %d bytes %d "
290 "fragments for DMA\n", tx_queue->queue, skb->len,
291 skb_shinfo(skb)->nr_frags + 1);
293 /* Mark the packet as transmitted, and free the SKB ourselves */
294 dev_kfree_skb_any(skb);
300 if (tx_queue->stopped == 1)
304 /* Work backwards until we hit the original insert pointer value */
305 while (tx_queue->insert_count != tx_queue->write_count) {
306 --tx_queue->insert_count;
307 insert_ptr = tx_queue->insert_count & EFX_TXQ_MASK;
308 buffer = &tx_queue->buffer[insert_ptr];
309 efx_dequeue_buffer(tx_queue, buffer);
313 /* Free the fragment we were mid-way through pushing */
316 pci_unmap_single(pci_dev, unmap_addr, unmap_len,
319 pci_unmap_page(pci_dev, unmap_addr, unmap_len,
326 /* Remove packets from the TX queue
328 * This removes packets from the TX queue, up to and including the
331 static void efx_dequeue_buffers(struct efx_tx_queue *tx_queue,
334 struct efx_nic *efx = tx_queue->efx;
335 unsigned int stop_index, read_ptr;
337 stop_index = (index + 1) & EFX_TXQ_MASK;
338 read_ptr = tx_queue->read_count & EFX_TXQ_MASK;
340 while (read_ptr != stop_index) {
341 struct efx_tx_buffer *buffer = &tx_queue->buffer[read_ptr];
342 if (unlikely(buffer->len == 0)) {
343 EFX_ERR(tx_queue->efx, "TX queue %d spurious TX "
344 "completion id %x\n", tx_queue->queue,
346 efx_schedule_reset(efx, RESET_TYPE_TX_SKIP);
350 efx_dequeue_buffer(tx_queue, buffer);
351 buffer->continuation = true;
354 ++tx_queue->read_count;
355 read_ptr = tx_queue->read_count & EFX_TXQ_MASK;
359 /* Initiate a packet transmission. We use one channel per CPU
360 * (sharing when we have more CPUs than channels). On Falcon, the TX
361 * completion events will be directed back to the CPU that transmitted
362 * the packet, which should be cache-efficient.
364 * Context: non-blocking.
365 * Note that returning anything other than NETDEV_TX_OK will cause the
366 * OS to free the skb.
368 netdev_tx_t efx_hard_start_xmit(struct sk_buff *skb,
369 struct net_device *net_dev)
371 struct efx_nic *efx = netdev_priv(net_dev);
372 struct efx_tx_queue *tx_queue;
374 if (unlikely(efx->port_inhibited))
375 return NETDEV_TX_BUSY;
377 if (likely(skb->ip_summed == CHECKSUM_PARTIAL))
378 tx_queue = &efx->tx_queue[EFX_TX_QUEUE_OFFLOAD_CSUM];
380 tx_queue = &efx->tx_queue[EFX_TX_QUEUE_NO_CSUM];
382 return efx_enqueue_skb(tx_queue, skb);
385 void efx_xmit_done(struct efx_tx_queue *tx_queue, unsigned int index)
388 struct efx_nic *efx = tx_queue->efx;
390 EFX_BUG_ON_PARANOID(index > EFX_TXQ_MASK);
392 efx_dequeue_buffers(tx_queue, index);
394 /* See if we need to restart the netif queue. This barrier
395 * separates the update of read_count from the test of
398 if (unlikely(tx_queue->stopped) && likely(efx->port_enabled)) {
399 fill_level = tx_queue->insert_count - tx_queue->read_count;
400 if (fill_level < EFX_TXQ_THRESHOLD) {
401 EFX_BUG_ON_PARANOID(!efx_dev_registered(efx));
403 /* Do this under netif_tx_lock(), to avoid racing
404 * with efx_xmit(). */
405 netif_tx_lock(efx->net_dev);
406 if (tx_queue->stopped) {
407 tx_queue->stopped = 0;
410 netif_tx_unlock(efx->net_dev);
415 int efx_probe_tx_queue(struct efx_tx_queue *tx_queue)
417 struct efx_nic *efx = tx_queue->efx;
418 unsigned int txq_size;
421 EFX_LOG(efx, "creating TX queue %d\n", tx_queue->queue);
423 /* Allocate software ring */
424 txq_size = EFX_TXQ_SIZE * sizeof(*tx_queue->buffer);
425 tx_queue->buffer = kzalloc(txq_size, GFP_KERNEL);
426 if (!tx_queue->buffer)
428 for (i = 0; i <= EFX_TXQ_MASK; ++i)
429 tx_queue->buffer[i].continuation = true;
431 /* Allocate hardware ring */
432 rc = efx_nic_probe_tx(tx_queue);
439 kfree(tx_queue->buffer);
440 tx_queue->buffer = NULL;
444 void efx_init_tx_queue(struct efx_tx_queue *tx_queue)
446 EFX_LOG(tx_queue->efx, "initialising TX queue %d\n", tx_queue->queue);
448 tx_queue->insert_count = 0;
449 tx_queue->write_count = 0;
450 tx_queue->read_count = 0;
451 tx_queue->old_read_count = 0;
452 BUG_ON(tx_queue->stopped);
454 /* Set up TX descriptor ring */
455 efx_nic_init_tx(tx_queue);
458 void efx_release_tx_buffers(struct efx_tx_queue *tx_queue)
460 struct efx_tx_buffer *buffer;
462 if (!tx_queue->buffer)
465 /* Free any buffers left in the ring */
466 while (tx_queue->read_count != tx_queue->write_count) {
467 buffer = &tx_queue->buffer[tx_queue->read_count & EFX_TXQ_MASK];
468 efx_dequeue_buffer(tx_queue, buffer);
469 buffer->continuation = true;
472 ++tx_queue->read_count;
476 void efx_fini_tx_queue(struct efx_tx_queue *tx_queue)
478 EFX_LOG(tx_queue->efx, "shutting down TX queue %d\n", tx_queue->queue);
480 /* Flush TX queue, remove descriptor ring */
481 efx_nic_fini_tx(tx_queue);
483 efx_release_tx_buffers(tx_queue);
485 /* Free up TSO header cache */
486 efx_fini_tso(tx_queue);
488 /* Release queue's stop on port, if any */
489 if (tx_queue->stopped) {
490 tx_queue->stopped = 0;
491 efx_wake_queue(tx_queue->efx);
495 void efx_remove_tx_queue(struct efx_tx_queue *tx_queue)
497 EFX_LOG(tx_queue->efx, "destroying TX queue %d\n", tx_queue->queue);
498 efx_nic_remove_tx(tx_queue);
500 kfree(tx_queue->buffer);
501 tx_queue->buffer = NULL;
505 /* Efx TCP segmentation acceleration.
507 * Why? Because by doing it here in the driver we can go significantly
508 * faster than the GSO.
510 * Requires TX checksum offload support.
513 /* Number of bytes inserted at the start of a TSO header buffer,
514 * similar to NET_IP_ALIGN.
516 #ifdef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS
517 #define TSOH_OFFSET 0
519 #define TSOH_OFFSET NET_IP_ALIGN
522 #define TSOH_BUFFER(tsoh) ((u8 *)(tsoh + 1) + TSOH_OFFSET)
524 /* Total size of struct efx_tso_header, buffer and padding */
525 #define TSOH_SIZE(hdr_len) \
526 (sizeof(struct efx_tso_header) + TSOH_OFFSET + hdr_len)
528 /* Size of blocks on free list. Larger blocks must be allocated from
531 #define TSOH_STD_SIZE 128
533 #define PTR_DIFF(p1, p2) ((u8 *)(p1) - (u8 *)(p2))
534 #define ETH_HDR_LEN(skb) (skb_network_header(skb) - (skb)->data)
535 #define SKB_TCP_OFF(skb) PTR_DIFF(tcp_hdr(skb), (skb)->data)
536 #define SKB_IPV4_OFF(skb) PTR_DIFF(ip_hdr(skb), (skb)->data)
537 #define SKB_IPV6_OFF(skb) PTR_DIFF(ipv6_hdr(skb), (skb)->data)
540 * struct tso_state - TSO state for an SKB
541 * @out_len: Remaining length in current segment
542 * @seqnum: Current sequence number
543 * @ipv4_id: Current IPv4 ID, host endian
544 * @packet_space: Remaining space in current packet
545 * @dma_addr: DMA address of current position
546 * @in_len: Remaining length in current SKB fragment
547 * @unmap_len: Length of SKB fragment
548 * @unmap_addr: DMA address of SKB fragment
549 * @unmap_single: DMA single vs page mapping flag
550 * @protocol: Network protocol (after any VLAN header)
551 * @header_len: Number of bytes of header
552 * @full_packet_size: Number of bytes to put in each outgoing segment
554 * The state used during segmentation. It is put into this data structure
555 * just to make it easy to pass into inline functions.
558 /* Output position */
562 unsigned packet_space;
568 dma_addr_t unmap_addr;
573 int full_packet_size;
578 * Verify that our various assumptions about sk_buffs and the conditions
579 * under which TSO will be attempted hold true. Return the protocol number.
581 static __be16 efx_tso_check_protocol(struct sk_buff *skb)
583 __be16 protocol = skb->protocol;
585 EFX_BUG_ON_PARANOID(((struct ethhdr *)skb->data)->h_proto !=
587 if (protocol == htons(ETH_P_8021Q)) {
588 /* Find the encapsulated protocol; reset network header
589 * and transport header based on that. */
590 struct vlan_ethhdr *veh = (struct vlan_ethhdr *)skb->data;
591 protocol = veh->h_vlan_encapsulated_proto;
592 skb_set_network_header(skb, sizeof(*veh));
593 if (protocol == htons(ETH_P_IP))
594 skb_set_transport_header(skb, sizeof(*veh) +
595 4 * ip_hdr(skb)->ihl);
596 else if (protocol == htons(ETH_P_IPV6))
597 skb_set_transport_header(skb, sizeof(*veh) +
598 sizeof(struct ipv6hdr));
601 if (protocol == htons(ETH_P_IP)) {
602 EFX_BUG_ON_PARANOID(ip_hdr(skb)->protocol != IPPROTO_TCP);
604 EFX_BUG_ON_PARANOID(protocol != htons(ETH_P_IPV6));
605 EFX_BUG_ON_PARANOID(ipv6_hdr(skb)->nexthdr != NEXTHDR_TCP);
607 EFX_BUG_ON_PARANOID((PTR_DIFF(tcp_hdr(skb), skb->data)
608 + (tcp_hdr(skb)->doff << 2u)) >
616 * Allocate a page worth of efx_tso_header structures, and string them
617 * into the tx_queue->tso_headers_free linked list. Return 0 or -ENOMEM.
619 static int efx_tsoh_block_alloc(struct efx_tx_queue *tx_queue)
622 struct pci_dev *pci_dev = tx_queue->efx->pci_dev;
623 struct efx_tso_header *tsoh;
627 base_kva = pci_alloc_consistent(pci_dev, PAGE_SIZE, &dma_addr);
628 if (base_kva == NULL) {
629 EFX_ERR(tx_queue->efx, "Unable to allocate page for TSO"
634 /* pci_alloc_consistent() allocates pages. */
635 EFX_BUG_ON_PARANOID(dma_addr & (PAGE_SIZE - 1u));
637 for (kva = base_kva; kva < base_kva + PAGE_SIZE; kva += TSOH_STD_SIZE) {
638 tsoh = (struct efx_tso_header *)kva;
639 tsoh->dma_addr = dma_addr + (TSOH_BUFFER(tsoh) - base_kva);
640 tsoh->next = tx_queue->tso_headers_free;
641 tx_queue->tso_headers_free = tsoh;
648 /* Free up a TSO header, and all others in the same page. */
649 static void efx_tsoh_block_free(struct efx_tx_queue *tx_queue,
650 struct efx_tso_header *tsoh,
651 struct pci_dev *pci_dev)
653 struct efx_tso_header **p;
654 unsigned long base_kva;
657 base_kva = (unsigned long)tsoh & PAGE_MASK;
658 base_dma = tsoh->dma_addr & PAGE_MASK;
660 p = &tx_queue->tso_headers_free;
662 if (((unsigned long)*p & PAGE_MASK) == base_kva)
668 pci_free_consistent(pci_dev, PAGE_SIZE, (void *)base_kva, base_dma);
671 static struct efx_tso_header *
672 efx_tsoh_heap_alloc(struct efx_tx_queue *tx_queue, size_t header_len)
674 struct efx_tso_header *tsoh;
676 tsoh = kmalloc(TSOH_SIZE(header_len), GFP_ATOMIC | GFP_DMA);
680 tsoh->dma_addr = pci_map_single(tx_queue->efx->pci_dev,
681 TSOH_BUFFER(tsoh), header_len,
683 if (unlikely(pci_dma_mapping_error(tx_queue->efx->pci_dev,
689 tsoh->unmap_len = header_len;
694 efx_tsoh_heap_free(struct efx_tx_queue *tx_queue, struct efx_tso_header *tsoh)
696 pci_unmap_single(tx_queue->efx->pci_dev,
697 tsoh->dma_addr, tsoh->unmap_len,
703 * efx_tx_queue_insert - push descriptors onto the TX queue
704 * @tx_queue: Efx TX queue
705 * @dma_addr: DMA address of fragment
706 * @len: Length of fragment
707 * @final_buffer: The final buffer inserted into the queue
709 * Push descriptors onto the TX queue. Return 0 on success or 1 if
712 static int efx_tx_queue_insert(struct efx_tx_queue *tx_queue,
713 dma_addr_t dma_addr, unsigned len,
714 struct efx_tx_buffer **final_buffer)
716 struct efx_tx_buffer *buffer;
717 struct efx_nic *efx = tx_queue->efx;
718 unsigned dma_len, fill_level, insert_ptr;
721 EFX_BUG_ON_PARANOID(len <= 0);
723 fill_level = tx_queue->insert_count - tx_queue->old_read_count;
724 /* -1 as there is no way to represent all descriptors used */
725 q_space = EFX_TXQ_MASK - 1 - fill_level;
728 if (unlikely(q_space-- <= 0)) {
729 /* It might be that completions have happened
730 * since the xmit path last checked. Update
731 * the xmit path's copy of read_count.
734 /* This memory barrier protects the change of
735 * stopped from the access of read_count. */
737 tx_queue->old_read_count =
738 *(volatile unsigned *)&tx_queue->read_count;
739 fill_level = (tx_queue->insert_count
740 - tx_queue->old_read_count);
741 q_space = EFX_TXQ_MASK - 1 - fill_level;
742 if (unlikely(q_space-- <= 0)) {
743 *final_buffer = NULL;
750 insert_ptr = tx_queue->insert_count & EFX_TXQ_MASK;
751 buffer = &tx_queue->buffer[insert_ptr];
752 ++tx_queue->insert_count;
754 EFX_BUG_ON_PARANOID(tx_queue->insert_count -
755 tx_queue->read_count >
758 efx_tsoh_free(tx_queue, buffer);
759 EFX_BUG_ON_PARANOID(buffer->len);
760 EFX_BUG_ON_PARANOID(buffer->unmap_len);
761 EFX_BUG_ON_PARANOID(buffer->skb);
762 EFX_BUG_ON_PARANOID(!buffer->continuation);
763 EFX_BUG_ON_PARANOID(buffer->tsoh);
765 buffer->dma_addr = dma_addr;
767 dma_len = efx_max_tx_len(efx, dma_addr);
769 /* If there is enough space to send then do so */
773 buffer->len = dma_len; /* Don't set the other members */
778 EFX_BUG_ON_PARANOID(!len);
780 *final_buffer = buffer;
786 * Put a TSO header into the TX queue.
788 * This is special-cased because we know that it is small enough to fit in
789 * a single fragment, and we know it doesn't cross a page boundary. It
790 * also allows us to not worry about end-of-packet etc.
792 static void efx_tso_put_header(struct efx_tx_queue *tx_queue,
793 struct efx_tso_header *tsoh, unsigned len)
795 struct efx_tx_buffer *buffer;
797 buffer = &tx_queue->buffer[tx_queue->insert_count & EFX_TXQ_MASK];
798 efx_tsoh_free(tx_queue, buffer);
799 EFX_BUG_ON_PARANOID(buffer->len);
800 EFX_BUG_ON_PARANOID(buffer->unmap_len);
801 EFX_BUG_ON_PARANOID(buffer->skb);
802 EFX_BUG_ON_PARANOID(!buffer->continuation);
803 EFX_BUG_ON_PARANOID(buffer->tsoh);
805 buffer->dma_addr = tsoh->dma_addr;
808 ++tx_queue->insert_count;
812 /* Remove descriptors put into a tx_queue. */
813 static void efx_enqueue_unwind(struct efx_tx_queue *tx_queue)
815 struct efx_tx_buffer *buffer;
816 dma_addr_t unmap_addr;
818 /* Work backwards until we hit the original insert pointer value */
819 while (tx_queue->insert_count != tx_queue->write_count) {
820 --tx_queue->insert_count;
821 buffer = &tx_queue->buffer[tx_queue->insert_count &
823 efx_tsoh_free(tx_queue, buffer);
824 EFX_BUG_ON_PARANOID(buffer->skb);
825 if (buffer->unmap_len) {
826 unmap_addr = (buffer->dma_addr + buffer->len -
828 if (buffer->unmap_single)
829 pci_unmap_single(tx_queue->efx->pci_dev,
830 unmap_addr, buffer->unmap_len,
833 pci_unmap_page(tx_queue->efx->pci_dev,
834 unmap_addr, buffer->unmap_len,
836 buffer->unmap_len = 0;
839 buffer->continuation = true;
844 /* Parse the SKB header and initialise state. */
845 static void tso_start(struct tso_state *st, const struct sk_buff *skb)
847 /* All ethernet/IP/TCP headers combined size is TCP header size
848 * plus offset of TCP header relative to start of packet.
850 st->header_len = ((tcp_hdr(skb)->doff << 2u)
851 + PTR_DIFF(tcp_hdr(skb), skb->data));
852 st->full_packet_size = st->header_len + skb_shinfo(skb)->gso_size;
854 if (st->protocol == htons(ETH_P_IP))
855 st->ipv4_id = ntohs(ip_hdr(skb)->id);
858 st->seqnum = ntohl(tcp_hdr(skb)->seq);
860 EFX_BUG_ON_PARANOID(tcp_hdr(skb)->urg);
861 EFX_BUG_ON_PARANOID(tcp_hdr(skb)->syn);
862 EFX_BUG_ON_PARANOID(tcp_hdr(skb)->rst);
864 st->packet_space = st->full_packet_size;
865 st->out_len = skb->len - st->header_len;
867 st->unmap_single = false;
870 static int tso_get_fragment(struct tso_state *st, struct efx_nic *efx,
873 st->unmap_addr = pci_map_page(efx->pci_dev, frag->page,
874 frag->page_offset, frag->size,
876 if (likely(!pci_dma_mapping_error(efx->pci_dev, st->unmap_addr))) {
877 st->unmap_single = false;
878 st->unmap_len = frag->size;
879 st->in_len = frag->size;
880 st->dma_addr = st->unmap_addr;
886 static int tso_get_head_fragment(struct tso_state *st, struct efx_nic *efx,
887 const struct sk_buff *skb)
889 int hl = st->header_len;
890 int len = skb_headlen(skb) - hl;
892 st->unmap_addr = pci_map_single(efx->pci_dev, skb->data + hl,
893 len, PCI_DMA_TODEVICE);
894 if (likely(!pci_dma_mapping_error(efx->pci_dev, st->unmap_addr))) {
895 st->unmap_single = true;
898 st->dma_addr = st->unmap_addr;
906 * tso_fill_packet_with_fragment - form descriptors for the current fragment
907 * @tx_queue: Efx TX queue
908 * @skb: Socket buffer
911 * Form descriptors for the current fragment, until we reach the end
912 * of fragment or end-of-packet. Return 0 on success, 1 if not enough
913 * space in @tx_queue.
915 static int tso_fill_packet_with_fragment(struct efx_tx_queue *tx_queue,
916 const struct sk_buff *skb,
917 struct tso_state *st)
919 struct efx_tx_buffer *buffer;
920 int n, end_of_packet, rc;
924 if (st->packet_space == 0)
927 EFX_BUG_ON_PARANOID(st->in_len <= 0);
928 EFX_BUG_ON_PARANOID(st->packet_space <= 0);
930 n = min(st->in_len, st->packet_space);
932 st->packet_space -= n;
936 rc = efx_tx_queue_insert(tx_queue, st->dma_addr, n, &buffer);
937 if (likely(rc == 0)) {
938 if (st->out_len == 0)
939 /* Transfer ownership of the skb */
942 end_of_packet = st->out_len == 0 || st->packet_space == 0;
943 buffer->continuation = !end_of_packet;
945 if (st->in_len == 0) {
946 /* Transfer ownership of the pci mapping */
947 buffer->unmap_len = st->unmap_len;
948 buffer->unmap_single = st->unmap_single;
959 * tso_start_new_packet - generate a new header and prepare for the new packet
960 * @tx_queue: Efx TX queue
961 * @skb: Socket buffer
964 * Generate a new header and prepare for the new packet. Return 0 on
965 * success, or -1 if failed to alloc header.
967 static int tso_start_new_packet(struct efx_tx_queue *tx_queue,
968 const struct sk_buff *skb,
969 struct tso_state *st)
971 struct efx_tso_header *tsoh;
972 struct tcphdr *tsoh_th;
976 /* Allocate a DMA-mapped header buffer. */
977 if (likely(TSOH_SIZE(st->header_len) <= TSOH_STD_SIZE)) {
978 if (tx_queue->tso_headers_free == NULL) {
979 if (efx_tsoh_block_alloc(tx_queue))
982 EFX_BUG_ON_PARANOID(!tx_queue->tso_headers_free);
983 tsoh = tx_queue->tso_headers_free;
984 tx_queue->tso_headers_free = tsoh->next;
987 tx_queue->tso_long_headers++;
988 tsoh = efx_tsoh_heap_alloc(tx_queue, st->header_len);
993 header = TSOH_BUFFER(tsoh);
994 tsoh_th = (struct tcphdr *)(header + SKB_TCP_OFF(skb));
996 /* Copy and update the headers. */
997 memcpy(header, skb->data, st->header_len);
999 tsoh_th->seq = htonl(st->seqnum);
1000 st->seqnum += skb_shinfo(skb)->gso_size;
1001 if (st->out_len > skb_shinfo(skb)->gso_size) {
1002 /* This packet will not finish the TSO burst. */
1003 ip_length = st->full_packet_size - ETH_HDR_LEN(skb);
1007 /* This packet will be the last in the TSO burst. */
1008 ip_length = st->header_len - ETH_HDR_LEN(skb) + st->out_len;
1009 tsoh_th->fin = tcp_hdr(skb)->fin;
1010 tsoh_th->psh = tcp_hdr(skb)->psh;
1013 if (st->protocol == htons(ETH_P_IP)) {
1014 struct iphdr *tsoh_iph =
1015 (struct iphdr *)(header + SKB_IPV4_OFF(skb));
1017 tsoh_iph->tot_len = htons(ip_length);
1019 /* Linux leaves suitable gaps in the IP ID space for us to fill. */
1020 tsoh_iph->id = htons(st->ipv4_id);
1023 struct ipv6hdr *tsoh_iph =
1024 (struct ipv6hdr *)(header + SKB_IPV6_OFF(skb));
1026 tsoh_iph->payload_len = htons(ip_length - sizeof(*tsoh_iph));
1029 st->packet_space = skb_shinfo(skb)->gso_size;
1030 ++tx_queue->tso_packets;
1032 /* Form a descriptor for this header. */
1033 efx_tso_put_header(tx_queue, tsoh, st->header_len);
1040 * efx_enqueue_skb_tso - segment and transmit a TSO socket buffer
1041 * @tx_queue: Efx TX queue
1042 * @skb: Socket buffer
1044 * Context: You must hold netif_tx_lock() to call this function.
1046 * Add socket buffer @skb to @tx_queue, doing TSO or return != 0 if
1047 * @skb was not enqueued. In all cases @skb is consumed. Return
1048 * %NETDEV_TX_OK or %NETDEV_TX_BUSY.
1050 static int efx_enqueue_skb_tso(struct efx_tx_queue *tx_queue,
1051 struct sk_buff *skb)
1053 struct efx_nic *efx = tx_queue->efx;
1054 int frag_i, rc, rc2 = NETDEV_TX_OK;
1055 struct tso_state state;
1057 /* Find the packet protocol and sanity-check it */
1058 state.protocol = efx_tso_check_protocol(skb);
1060 EFX_BUG_ON_PARANOID(tx_queue->write_count != tx_queue->insert_count);
1062 tso_start(&state, skb);
1064 /* Assume that skb header area contains exactly the headers, and
1065 * all payload is in the frag list.
1067 if (skb_headlen(skb) == state.header_len) {
1068 /* Grab the first payload fragment. */
1069 EFX_BUG_ON_PARANOID(skb_shinfo(skb)->nr_frags < 1);
1071 rc = tso_get_fragment(&state, efx,
1072 skb_shinfo(skb)->frags + frag_i);
1076 rc = tso_get_head_fragment(&state, efx, skb);
1082 if (tso_start_new_packet(tx_queue, skb, &state) < 0)
1086 rc = tso_fill_packet_with_fragment(tx_queue, skb, &state);
1090 /* Move onto the next fragment? */
1091 if (state.in_len == 0) {
1092 if (++frag_i >= skb_shinfo(skb)->nr_frags)
1093 /* End of payload reached. */
1095 rc = tso_get_fragment(&state, efx,
1096 skb_shinfo(skb)->frags + frag_i);
1101 /* Start at new packet? */
1102 if (state.packet_space == 0 &&
1103 tso_start_new_packet(tx_queue, skb, &state) < 0)
1107 /* Pass off to hardware */
1108 efx_nic_push_buffers(tx_queue);
1110 tx_queue->tso_bursts++;
1111 return NETDEV_TX_OK;
1114 EFX_ERR(efx, "Out of memory for TSO headers, or PCI mapping error\n");
1115 dev_kfree_skb_any(skb);
1119 rc2 = NETDEV_TX_BUSY;
1121 /* Stop the queue if it wasn't stopped before. */
1122 if (tx_queue->stopped == 1)
1123 efx_stop_queue(efx);
1126 /* Free the DMA mapping we were in the process of writing out */
1127 if (state.unmap_len) {
1128 if (state.unmap_single)
1129 pci_unmap_single(efx->pci_dev, state.unmap_addr,
1130 state.unmap_len, PCI_DMA_TODEVICE);
1132 pci_unmap_page(efx->pci_dev, state.unmap_addr,
1133 state.unmap_len, PCI_DMA_TODEVICE);
1136 efx_enqueue_unwind(tx_queue);
1142 * Free up all TSO datastructures associated with tx_queue. This
1143 * routine should be called only once the tx_queue is both empty and
1144 * will no longer be used.
1146 static void efx_fini_tso(struct efx_tx_queue *tx_queue)
1150 if (tx_queue->buffer) {
1151 for (i = 0; i <= EFX_TXQ_MASK; ++i)
1152 efx_tsoh_free(tx_queue, &tx_queue->buffer[i]);
1155 while (tx_queue->tso_headers_free != NULL)
1156 efx_tsoh_block_free(tx_queue, tx_queue->tso_headers_free,
1157 tx_queue->efx->pci_dev);