1// SPDX-License-Identifier: GPL-2.0-only
2/****************************************************************************
3 * Driver for Solarflare network controllers and boards
4 * Copyright 2005-2006 Fen Systems Ltd.
5 * Copyright 2005-2015 Solarflare Communications Inc.
6 */
7
8#include <linux/pci.h>
9#include <linux/tcp.h>
10#include <linux/ip.h>
11#include <linux/in.h>
12#include <linux/ipv6.h>
13#include <linux/slab.h>
14#include <net/ipv6.h>
15#include <linux/if_ether.h>
16#include <linux/highmem.h>
17#include <linux/moduleparam.h>
18#include <linux/cache.h>
19#include "net_driver.h"
20#include "efx.h"
21#include "io.h"
22#include "nic.h"
23#include "tx.h"
24#include "workarounds.h"
25#include "ef10_regs.h"
26
27/* Efx legacy TCP segmentation acceleration.
28 *
29 * Utilises firmware support to go faster than GSO (but not as fast as TSOv2).
30 *
31 * Requires TX checksum offload support.
32 */
33
34#define PTR_DIFF(p1, p2) ((u8 *)(p1) - (u8 *)(p2))
35
36/**
37 * struct tso_state - TSO state for an SKB
38 * @out_len: Remaining length in current segment
39 * @seqnum: Current sequence number
40 * @ipv4_id: Current IPv4 ID, host endian
41 * @packet_space: Remaining space in current packet
42 * @dma_addr: DMA address of current position
43 * @in_len: Remaining length in current SKB fragment
44 * @unmap_len: Length of SKB fragment
45 * @unmap_addr: DMA address of SKB fragment
46 * @protocol: Network protocol (after any VLAN header)
47 * @ip_off: Offset of IP header
48 * @tcp_off: Offset of TCP header
49 * @header_len: Number of bytes of header
50 * @ip_base_len: IPv4 tot_len or IPv6 payload_len, before TCP payload
51 * @header_dma_addr: Header DMA address
52 * @header_unmap_len: Header DMA mapped length
53 *
54 * The state used during segmentation. It is put into this data structure
55 * just to make it easy to pass into inline functions.
56 */
57struct tso_state {
58 /* Output position */
59 unsigned int out_len;
60 unsigned int seqnum;
61 u16 ipv4_id;
62 unsigned int packet_space;
63
64 /* Input position */
65 dma_addr_t dma_addr;
66 unsigned int in_len;
67 unsigned int unmap_len;
68 dma_addr_t unmap_addr;
69
70 __be16 protocol;
71 unsigned int ip_off;
72 unsigned int tcp_off;
73 unsigned int header_len;
74 unsigned int ip_base_len;
75 dma_addr_t header_dma_addr;
76 unsigned int header_unmap_len;
77};
78
79static inline void prefetch_ptr(struct efx_tx_queue *tx_queue)
80{
81 unsigned int insert_ptr = efx_tx_queue_get_insert_index(tx_queue);
82 char *ptr;
83
84 ptr = (char *) (tx_queue->buffer + insert_ptr);
85 prefetch(ptr);
86 prefetch(ptr + 0x80);
87
88 ptr = (char *)(((efx_qword_t *)tx_queue->txd.addr) + insert_ptr);
89 prefetch(ptr);
90 prefetch(ptr + 0x80);
91}
92
93/**
94 * efx_tx_queue_insert - push descriptors onto the TX queue
95 * @tx_queue: Efx TX queue
96 * @dma_addr: DMA address of fragment
97 * @len: Length of fragment
98 * @final_buffer: The final buffer inserted into the queue
99 *
100 * Push descriptors onto the TX queue.
101 */
102static void efx_tx_queue_insert(struct efx_tx_queue *tx_queue,
103 dma_addr_t dma_addr, unsigned int len,
104 struct efx_tx_buffer **final_buffer)
105{
106 struct efx_tx_buffer *buffer;
107 unsigned int dma_len;
108
109 EFX_WARN_ON_ONCE_PARANOID(len <= 0);
110
111 while (1) {
112 buffer = efx_tx_queue_get_insert_buffer(tx_queue);
113 ++tx_queue->insert_count;
114
115 EFX_WARN_ON_ONCE_PARANOID(tx_queue->insert_count -
116 tx_queue->read_count >=
117 tx_queue->efx->txq_entries);
118
119 buffer->dma_addr = dma_addr;
120
121 dma_len = tx_queue->efx->type->tx_limit_len(tx_queue,
122 dma_addr, len);
123
124 /* If there's space for everything this is our last buffer. */
125 if (dma_len >= len)
126 break;
127
128 buffer->len = dma_len;
129 buffer->flags = EFX_TX_BUF_CONT;
130 dma_addr += dma_len;
131 len -= dma_len;
132 }
133
134 EFX_WARN_ON_ONCE_PARANOID(!len);
135 buffer->len = len;
136 *final_buffer = buffer;
137}
138
139/*
140 * Verify that our various assumptions about sk_buffs and the conditions
141 * under which TSO will be attempted hold true. Return the protocol number.
142 */
143static __be16 efx_tso_check_protocol(struct sk_buff *skb)
144{
145 __be16 protocol = skb->protocol;
146
147 EFX_WARN_ON_ONCE_PARANOID(((struct ethhdr *)skb->data)->h_proto !=
148 protocol);
149 if (protocol == htons(ETH_P_8021Q)) {
150 struct vlan_ethhdr *veh = skb_vlan_eth_hdr(skb);
151
152 protocol = veh->h_vlan_encapsulated_proto;
153 }
154
155 if (protocol == htons(ETH_P_IP)) {
156 EFX_WARN_ON_ONCE_PARANOID(ip_hdr(skb)->protocol != IPPROTO_TCP);
157 } else {
158 EFX_WARN_ON_ONCE_PARANOID(protocol != htons(ETH_P_IPV6));
159 EFX_WARN_ON_ONCE_PARANOID(ipv6_hdr(skb)->nexthdr != NEXTHDR_TCP);
160 }
161 EFX_WARN_ON_ONCE_PARANOID((PTR_DIFF(tcp_hdr(skb), skb->data) +
162 (tcp_hdr(skb)->doff << 2u)) >
163 skb_headlen(skb));
164
165 return protocol;
166}
167
168/* Parse the SKB header and initialise state. */
169static int tso_start(struct tso_state *st, struct efx_nic *efx,
170 struct efx_tx_queue *tx_queue,
171 const struct sk_buff *skb)
172{
173 struct device *dma_dev = &efx->pci_dev->dev;
174 unsigned int header_len, in_len;
175 dma_addr_t dma_addr;
176
177 st->ip_off = skb_network_header(skb) - skb->data;
178 st->tcp_off = skb_transport_header(skb) - skb->data;
179 header_len = st->tcp_off + (tcp_hdr(skb)->doff << 2u);
180 in_len = skb_headlen(skb) - header_len;
181 st->header_len = header_len;
182 st->in_len = in_len;
183 if (st->protocol == htons(ETH_P_IP)) {
184 st->ip_base_len = st->header_len - st->ip_off;
185 st->ipv4_id = ntohs(ip_hdr(skb)->id);
186 } else {
187 st->ip_base_len = st->header_len - st->tcp_off;
188 st->ipv4_id = 0;
189 }
190 st->seqnum = ntohl(tcp_hdr(skb)->seq);
191
192 EFX_WARN_ON_ONCE_PARANOID(tcp_hdr(skb)->urg);
193 EFX_WARN_ON_ONCE_PARANOID(tcp_hdr(skb)->syn);
194 EFX_WARN_ON_ONCE_PARANOID(tcp_hdr(skb)->rst);
195
196 st->out_len = skb->len - header_len;
197
198 dma_addr = dma_map_single(dma_dev, skb->data,
199 skb_headlen(skb), DMA_TO_DEVICE);
200 st->header_dma_addr = dma_addr;
201 st->header_unmap_len = skb_headlen(skb);
202 st->dma_addr = dma_addr + header_len;
203 st->unmap_len = 0;
204
205 return unlikely(dma_mapping_error(dma_dev, dma_addr)) ? -ENOMEM : 0;
206}
207
208static int tso_get_fragment(struct tso_state *st, struct efx_nic *efx,
209 skb_frag_t *frag)
210{
211 st->unmap_addr = skb_frag_dma_map(dev: &efx->pci_dev->dev, frag, offset: 0,
212 size: skb_frag_size(frag), dir: DMA_TO_DEVICE);
213 if (likely(!dma_mapping_error(&efx->pci_dev->dev, st->unmap_addr))) {
214 st->unmap_len = skb_frag_size(frag);
215 st->in_len = skb_frag_size(frag);
216 st->dma_addr = st->unmap_addr;
217 return 0;
218 }
219 return -ENOMEM;
220}
221
222
223/**
224 * tso_fill_packet_with_fragment - form descriptors for the current fragment
225 * @tx_queue: Efx TX queue
226 * @skb: Socket buffer
227 * @st: TSO state
228 *
229 * Form descriptors for the current fragment, until we reach the end
230 * of fragment or end-of-packet.
231 */
232static void tso_fill_packet_with_fragment(struct efx_tx_queue *tx_queue,
233 const struct sk_buff *skb,
234 struct tso_state *st)
235{
236 struct efx_tx_buffer *buffer;
237 int n;
238
239 if (st->in_len == 0)
240 return;
241 if (st->packet_space == 0)
242 return;
243
244 EFX_WARN_ON_ONCE_PARANOID(st->in_len <= 0);
245 EFX_WARN_ON_ONCE_PARANOID(st->packet_space <= 0);
246
247 n = min(st->in_len, st->packet_space);
248
249 st->packet_space -= n;
250 st->out_len -= n;
251 st->in_len -= n;
252
253 efx_tx_queue_insert(tx_queue, dma_addr: st->dma_addr, len: n, final_buffer: &buffer);
254
255 if (st->out_len == 0) {
256 /* Transfer ownership of the skb */
257 buffer->skb = skb;
258 buffer->flags = EFX_TX_BUF_SKB;
259 } else if (st->packet_space != 0) {
260 buffer->flags = EFX_TX_BUF_CONT;
261 }
262
263 if (st->in_len == 0) {
264 /* Transfer ownership of the DMA mapping */
265 buffer->unmap_len = st->unmap_len;
266 buffer->dma_offset = buffer->unmap_len - buffer->len;
267 st->unmap_len = 0;
268 }
269
270 st->dma_addr += n;
271}
272
273
274#define TCP_FLAGS_OFFSET 13
275
276/**
277 * tso_start_new_packet - generate a new header and prepare for the new packet
278 * @tx_queue: Efx TX queue
279 * @skb: Socket buffer
280 * @st: TSO state
281 *
282 * Generate a new header and prepare for the new packet. Return 0 on
283 * success, or -%ENOMEM if failed to alloc header, or other negative error.
284 */
285static int tso_start_new_packet(struct efx_tx_queue *tx_queue,
286 const struct sk_buff *skb,
287 struct tso_state *st)
288{
289 struct efx_tx_buffer *buffer =
290 efx_tx_queue_get_insert_buffer(tx_queue);
291 bool is_last = st->out_len <= skb_shinfo(skb)->gso_size;
292 u8 tcp_flags_mask, tcp_flags;
293
294 if (!is_last) {
295 st->packet_space = skb_shinfo(skb)->gso_size;
296 tcp_flags_mask = 0x09; /* mask out FIN and PSH */
297 } else {
298 st->packet_space = st->out_len;
299 tcp_flags_mask = 0x00;
300 }
301
302 if (WARN_ON(!st->header_unmap_len))
303 return -EINVAL;
304 /* Send the original headers with a TSO option descriptor
305 * in front
306 */
307 tcp_flags = ((u8 *)tcp_hdr(skb))[TCP_FLAGS_OFFSET] & ~tcp_flags_mask;
308
309 buffer->flags = EFX_TX_BUF_OPTION;
310 buffer->len = 0;
311 buffer->unmap_len = 0;
312 EFX_POPULATE_QWORD_5(buffer->option,
313 ESF_DZ_TX_DESC_IS_OPT, 1,
314 ESF_DZ_TX_OPTION_TYPE,
315 ESE_DZ_TX_OPTION_DESC_TSO,
316 ESF_DZ_TX_TSO_TCP_FLAGS, tcp_flags,
317 ESF_DZ_TX_TSO_IP_ID, st->ipv4_id,
318 ESF_DZ_TX_TSO_TCP_SEQNO, st->seqnum);
319 ++tx_queue->insert_count;
320
321 /* We mapped the headers in tso_start(). Unmap them
322 * when the last segment is completed.
323 */
324 buffer = efx_tx_queue_get_insert_buffer(tx_queue);
325 buffer->dma_addr = st->header_dma_addr;
326 buffer->len = st->header_len;
327 if (is_last) {
328 buffer->flags = EFX_TX_BUF_CONT | EFX_TX_BUF_MAP_SINGLE;
329 buffer->unmap_len = st->header_unmap_len;
330 buffer->dma_offset = 0;
331 /* Ensure we only unmap them once in case of a
332 * later DMA mapping error and rollback
333 */
334 st->header_unmap_len = 0;
335 } else {
336 buffer->flags = EFX_TX_BUF_CONT;
337 buffer->unmap_len = 0;
338 }
339 ++tx_queue->insert_count;
340
341 st->seqnum += skb_shinfo(skb)->gso_size;
342
343 /* Linux leaves suitable gaps in the IP ID space for us to fill. */
344 ++st->ipv4_id;
345
346 return 0;
347}
348
349/**
350 * efx_enqueue_skb_tso - segment and transmit a TSO socket buffer
351 * @tx_queue: Efx TX queue
352 * @skb: Socket buffer
353 * @data_mapped: Did we map the data? Always set to true
354 * by this on success.
355 *
356 * Context: You must hold netif_tx_lock() to call this function.
357 *
358 * Add socket buffer @skb to @tx_queue, doing TSO or return != 0 if
359 * @skb was not enqueued. @skb is consumed unless return value is
360 * %EINVAL.
361 */
362int efx_enqueue_skb_tso(struct efx_tx_queue *tx_queue,
363 struct sk_buff *skb,
364 bool *data_mapped)
365{
366 struct efx_nic *efx = tx_queue->efx;
367 int frag_i, rc;
368 struct tso_state state;
369
370 if (tx_queue->tso_version != 1)
371 return -EINVAL;
372
373 prefetch(skb->data);
374
375 /* Find the packet protocol and sanity-check it */
376 state.protocol = efx_tso_check_protocol(skb);
377
378 EFX_WARN_ON_ONCE_PARANOID(tx_queue->write_count != tx_queue->insert_count);
379
380 rc = tso_start(st: &state, efx, tx_queue, skb);
381 if (rc)
382 goto fail;
383
384 if (likely(state.in_len == 0)) {
385 /* Grab the first payload fragment. */
386 EFX_WARN_ON_ONCE_PARANOID(skb_shinfo(skb)->nr_frags < 1);
387 frag_i = 0;
388 rc = tso_get_fragment(st: &state, efx,
389 skb_shinfo(skb)->frags + frag_i);
390 if (rc)
391 goto fail;
392 } else {
393 /* Payload starts in the header area. */
394 frag_i = -1;
395 }
396
397 rc = tso_start_new_packet(tx_queue, skb, st: &state);
398 if (rc)
399 goto fail;
400
401 prefetch_ptr(tx_queue);
402
403 while (1) {
404 tso_fill_packet_with_fragment(tx_queue, skb, st: &state);
405
406 /* Move onto the next fragment? */
407 if (state.in_len == 0) {
408 if (++frag_i >= skb_shinfo(skb)->nr_frags)
409 /* End of payload reached. */
410 break;
411 rc = tso_get_fragment(st: &state, efx,
412 skb_shinfo(skb)->frags + frag_i);
413 if (rc)
414 goto fail;
415 }
416
417 /* Start at new packet? */
418 if (state.packet_space == 0) {
419 rc = tso_start_new_packet(tx_queue, skb, st: &state);
420 if (rc)
421 goto fail;
422 }
423 }
424
425 *data_mapped = true;
426
427 return 0;
428
429fail:
430 if (rc == -ENOMEM)
431 netif_err(efx, tx_err, efx->net_dev,
432 "Out of memory for TSO headers, or DMA mapping error\n");
433 else
434 netif_err(efx, tx_err, efx->net_dev, "TSO failed, rc = %d\n", rc);
435
436 /* Free the DMA mapping we were in the process of writing out */
437 if (state.unmap_len) {
438 dma_unmap_page(&efx->pci_dev->dev, state.unmap_addr,
439 state.unmap_len, DMA_TO_DEVICE);
440 }
441
442 /* Free the header DMA mapping */
443 if (state.header_unmap_len)
444 dma_unmap_single(&efx->pci_dev->dev, state.header_dma_addr,
445 state.header_unmap_len, DMA_TO_DEVICE);
446
447 return rc;
448}
449

source code of linux/drivers/net/ethernet/sfc/tx_tso.c