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 2005-2013 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/cache.h>
18#include "net_driver.h"
19#include "efx.h"
20#include "io.h"
21#include "nic.h"
22#include "tx.h"
23#include "tx_common.h"
24#include "workarounds.h"
25
26static inline u8 *efx_tx_get_copy_buffer(struct efx_tx_queue *tx_queue,
27 struct efx_tx_buffer *buffer)
28{
29 unsigned int index = efx_tx_queue_get_insert_index(tx_queue);
30 struct efx_buffer *page_buf =
31 &tx_queue->cb_page[index >> (PAGE_SHIFT - EFX_TX_CB_ORDER)];
32 unsigned int offset =
33 ((index << EFX_TX_CB_ORDER) + NET_IP_ALIGN) & (PAGE_SIZE - 1);
34
35 if (unlikely(!page_buf->addr) &&
36 efx_siena_alloc_buffer(efx: tx_queue->efx, buffer: page_buf, PAGE_SIZE,
37 GFP_ATOMIC))
38 return NULL;
39 buffer->dma_addr = page_buf->dma_addr + offset;
40 buffer->unmap_len = 0;
41 return (u8 *)page_buf->addr + offset;
42}
43
44static void efx_tx_maybe_stop_queue(struct efx_tx_queue *txq1)
45{
46 /* We need to consider all queues that the net core sees as one */
47 struct efx_nic *efx = txq1->efx;
48 struct efx_tx_queue *txq2;
49 unsigned int fill_level;
50
51 fill_level = efx_channel_tx_old_fill_level(channel: txq1->channel);
52 if (likely(fill_level < efx->txq_stop_thresh))
53 return;
54
55 /* We used the stale old_read_count above, which gives us a
56 * pessimistic estimate of the fill level (which may even
57 * validly be >= efx->txq_entries). Now try again using
58 * read_count (more likely to be a cache miss).
59 *
60 * If we read read_count and then conditionally stop the
61 * queue, it is possible for the completion path to race with
62 * us and complete all outstanding descriptors in the middle,
63 * after which there will be no more completions to wake it.
64 * Therefore we stop the queue first, then read read_count
65 * (with a memory barrier to ensure the ordering), then
66 * restart the queue if the fill level turns out to be low
67 * enough.
68 */
69 netif_tx_stop_queue(dev_queue: txq1->core_txq);
70 smp_mb();
71 efx_for_each_channel_tx_queue(txq2, txq1->channel)
72 txq2->old_read_count = READ_ONCE(txq2->read_count);
73
74 fill_level = efx_channel_tx_old_fill_level(channel: txq1->channel);
75 EFX_WARN_ON_ONCE_PARANOID(fill_level >= efx->txq_entries);
76 if (likely(fill_level < efx->txq_stop_thresh)) {
77 smp_mb();
78 if (likely(!efx->loopback_selftest))
79 netif_tx_start_queue(dev_queue: txq1->core_txq);
80 }
81}
82
83static int efx_enqueue_skb_copy(struct efx_tx_queue *tx_queue,
84 struct sk_buff *skb)
85{
86 unsigned int copy_len = skb->len;
87 struct efx_tx_buffer *buffer;
88 u8 *copy_buffer;
89 int rc;
90
91 EFX_WARN_ON_ONCE_PARANOID(copy_len > EFX_TX_CB_SIZE);
92
93 buffer = efx_tx_queue_get_insert_buffer(tx_queue);
94
95 copy_buffer = efx_tx_get_copy_buffer(tx_queue, buffer);
96 if (unlikely(!copy_buffer))
97 return -ENOMEM;
98
99 rc = skb_copy_bits(skb, offset: 0, to: copy_buffer, len: copy_len);
100 EFX_WARN_ON_PARANOID(rc);
101 buffer->len = copy_len;
102
103 buffer->skb = skb;
104 buffer->flags = EFX_TX_BUF_SKB;
105
106 ++tx_queue->insert_count;
107 return rc;
108}
109
110/* Send any pending traffic for a channel. xmit_more is shared across all
111 * queues for a channel, so we must check all of them.
112 */
113static void efx_tx_send_pending(struct efx_channel *channel)
114{
115 struct efx_tx_queue *q;
116
117 efx_for_each_channel_tx_queue(q, channel) {
118 if (q->xmit_pending)
119 efx_nic_push_buffers(tx_queue: q);
120 }
121}
122
123/*
124 * Add a socket buffer to a TX queue
125 *
126 * This maps all fragments of a socket buffer for DMA and adds them to
127 * the TX queue. The queue's insert pointer will be incremented by
128 * the number of fragments in the socket buffer.
129 *
130 * If any DMA mapping fails, any mapped fragments will be unmapped,
131 * the queue's insert pointer will be restored to its original value.
132 *
133 * This function is split out from efx_siena_hard_start_xmit to allow the
134 * loopback test to direct packets via specific TX queues.
135 *
136 * Returns NETDEV_TX_OK.
137 * You must hold netif_tx_lock() to call this function.
138 */
139netdev_tx_t __efx_siena_enqueue_skb(struct efx_tx_queue *tx_queue,
140 struct sk_buff *skb)
141{
142 unsigned int old_insert_count = tx_queue->insert_count;
143 bool xmit_more = netdev_xmit_more();
144 bool data_mapped = false;
145 unsigned int segments;
146 unsigned int skb_len;
147 int rc;
148
149 skb_len = skb->len;
150 segments = skb_is_gso(skb) ? skb_shinfo(skb)->gso_segs : 0;
151 if (segments == 1)
152 segments = 0; /* Don't use TSO for a single segment. */
153
154 /* Handle TSO first - it's *possible* (although unlikely) that we might
155 * be passed a packet to segment that's smaller than the copybreak/PIO
156 * size limit.
157 */
158 if (segments) {
159 rc = efx_siena_tx_tso_fallback(tx_queue, skb);
160 tx_queue->tso_fallbacks++;
161 if (rc == 0)
162 return 0;
163 goto err;
164 } else if (skb->data_len && skb_len <= EFX_TX_CB_SIZE) {
165 /* Pad short packets or coalesce short fragmented packets. */
166 if (efx_enqueue_skb_copy(tx_queue, skb))
167 goto err;
168 tx_queue->cb_packets++;
169 data_mapped = true;
170 }
171
172 /* Map for DMA and create descriptors if we haven't done so already. */
173 if (!data_mapped && (efx_siena_tx_map_data(tx_queue, skb, segment_count: segments)))
174 goto err;
175
176 efx_tx_maybe_stop_queue(txq1: tx_queue);
177
178 tx_queue->xmit_pending = true;
179
180 /* Pass off to hardware */
181 if (__netdev_tx_sent_queue(dev_queue: tx_queue->core_txq, bytes: skb_len, xmit_more))
182 efx_tx_send_pending(channel: tx_queue->channel);
183
184 tx_queue->tx_packets++;
185 return NETDEV_TX_OK;
186
187
188err:
189 efx_siena_enqueue_unwind(tx_queue, insert_count: old_insert_count);
190 dev_kfree_skb_any(skb);
191
192 /* If we're not expecting another transmit and we had something to push
193 * on this queue or a partner queue then we need to push here to get the
194 * previous packets out.
195 */
196 if (!xmit_more)
197 efx_tx_send_pending(channel: tx_queue->channel);
198
199 return NETDEV_TX_OK;
200}
201
202/* Transmit a packet from an XDP buffer
203 *
204 * Returns number of packets sent on success, error code otherwise.
205 * Runs in NAPI context, either in our poll (for XDP TX) or a different NIC
206 * (for XDP redirect).
207 */
208int efx_siena_xdp_tx_buffers(struct efx_nic *efx, int n, struct xdp_frame **xdpfs,
209 bool flush)
210{
211 struct efx_tx_buffer *tx_buffer;
212 struct efx_tx_queue *tx_queue;
213 struct xdp_frame *xdpf;
214 dma_addr_t dma_addr;
215 unsigned int len;
216 int space;
217 int cpu;
218 int i = 0;
219
220 if (unlikely(n && !xdpfs))
221 return -EINVAL;
222 if (unlikely(!n))
223 return 0;
224
225 cpu = raw_smp_processor_id();
226 if (unlikely(cpu >= efx->xdp_tx_queue_count))
227 return -EINVAL;
228
229 tx_queue = efx->xdp_tx_queues[cpu];
230 if (unlikely(!tx_queue))
231 return -EINVAL;
232
233 if (!tx_queue->initialised)
234 return -EINVAL;
235
236 if (efx->xdp_txq_queues_mode != EFX_XDP_TX_QUEUES_DEDICATED)
237 HARD_TX_LOCK(efx->net_dev, tx_queue->core_txq, cpu);
238
239 /* If we're borrowing net stack queues we have to handle stop-restart
240 * or we might block the queue and it will be considered as frozen
241 */
242 if (efx->xdp_txq_queues_mode == EFX_XDP_TX_QUEUES_BORROWED) {
243 if (netif_tx_queue_stopped(dev_queue: tx_queue->core_txq))
244 goto unlock;
245 efx_tx_maybe_stop_queue(txq1: tx_queue);
246 }
247
248 /* Check for available space. We should never need multiple
249 * descriptors per frame.
250 */
251 space = efx->txq_entries +
252 tx_queue->read_count - tx_queue->insert_count;
253
254 for (i = 0; i < n; i++) {
255 xdpf = xdpfs[i];
256
257 if (i >= space)
258 break;
259
260 /* We'll want a descriptor for this tx. */
261 prefetchw(x: __efx_tx_queue_get_insert_buffer(tx_queue));
262
263 len = xdpf->len;
264
265 /* Map for DMA. */
266 dma_addr = dma_map_single(&efx->pci_dev->dev,
267 xdpf->data, len,
268 DMA_TO_DEVICE);
269 if (dma_mapping_error(dev: &efx->pci_dev->dev, dma_addr))
270 break;
271
272 /* Create descriptor and set up for unmapping DMA. */
273 tx_buffer = efx_siena_tx_map_chunk(tx_queue, dma_addr, len);
274 tx_buffer->xdpf = xdpf;
275 tx_buffer->flags = EFX_TX_BUF_XDP |
276 EFX_TX_BUF_MAP_SINGLE;
277 tx_buffer->dma_offset = 0;
278 tx_buffer->unmap_len = len;
279 tx_queue->tx_packets++;
280 }
281
282 /* Pass mapped frames to hardware. */
283 if (flush && i > 0)
284 efx_nic_push_buffers(tx_queue);
285
286unlock:
287 if (efx->xdp_txq_queues_mode != EFX_XDP_TX_QUEUES_DEDICATED)
288 HARD_TX_UNLOCK(efx->net_dev, tx_queue->core_txq);
289
290 return i == 0 ? -EIO : i;
291}
292
293/* Initiate a packet transmission. We use one channel per CPU
294 * (sharing when we have more CPUs than channels).
295 *
296 * Context: non-blocking.
297 * Should always return NETDEV_TX_OK and consume the skb.
298 */
299netdev_tx_t efx_siena_hard_start_xmit(struct sk_buff *skb,
300 struct net_device *net_dev)
301{
302 struct efx_nic *efx = netdev_priv(dev: net_dev);
303 struct efx_tx_queue *tx_queue;
304 unsigned index, type;
305
306 EFX_WARN_ON_PARANOID(!netif_device_present(net_dev));
307
308 index = skb_get_queue_mapping(skb);
309 type = efx_tx_csum_type_skb(skb);
310 if (index >= efx->n_tx_channels) {
311 index -= efx->n_tx_channels;
312 type |= EFX_TXQ_TYPE_HIGHPRI;
313 }
314
315 /* PTP "event" packet */
316 if (unlikely(efx_xmit_with_hwtstamp(skb)) &&
317 ((efx_siena_ptp_use_mac_tx_timestamps(efx) && efx->ptp_data) ||
318 unlikely(efx_siena_ptp_is_ptp_tx(efx, skb)))) {
319 /* There may be existing transmits on the channel that are
320 * waiting for this packet to trigger the doorbell write.
321 * We need to send the packets at this point.
322 */
323 efx_tx_send_pending(channel: efx_get_tx_channel(efx, index));
324 return efx_siena_ptp_tx(efx, skb);
325 }
326
327 tx_queue = efx_get_tx_queue(efx, index, type);
328 if (WARN_ON_ONCE(!tx_queue)) {
329 /* We don't have a TXQ of the right type.
330 * This should never happen, as we don't advertise offload
331 * features unless we can support them.
332 */
333 dev_kfree_skb_any(skb);
334 /* If we're not expecting another transmit and we had something to push
335 * on this queue or a partner queue then we need to push here to get the
336 * previous packets out.
337 */
338 if (!netdev_xmit_more())
339 efx_tx_send_pending(channel: efx_get_tx_channel(efx, index));
340 return NETDEV_TX_OK;
341 }
342
343 return __efx_siena_enqueue_skb(tx_queue, skb);
344}
345
346void efx_siena_init_tx_queue_core_txq(struct efx_tx_queue *tx_queue)
347{
348 struct efx_nic *efx = tx_queue->efx;
349
350 /* Must be inverse of queue lookup in efx_siena_hard_start_xmit() */
351 tx_queue->core_txq =
352 netdev_get_tx_queue(dev: efx->net_dev,
353 index: tx_queue->channel->channel +
354 ((tx_queue->type & EFX_TXQ_TYPE_HIGHPRI) ?
355 efx->n_tx_channels : 0));
356}
357
358int efx_siena_setup_tc(struct net_device *net_dev, enum tc_setup_type type,
359 void *type_data)
360{
361 struct efx_nic *efx = netdev_priv(dev: net_dev);
362 struct tc_mqprio_qopt *mqprio = type_data;
363 unsigned tc, num_tc;
364
365 if (type != TC_SETUP_QDISC_MQPRIO)
366 return -EOPNOTSUPP;
367
368 /* Only Siena supported highpri queues */
369 if (efx_nic_rev(efx) > EFX_REV_SIENA_A0)
370 return -EOPNOTSUPP;
371
372 num_tc = mqprio->num_tc;
373
374 if (num_tc > EFX_MAX_TX_TC)
375 return -EINVAL;
376
377 mqprio->hw = TC_MQPRIO_HW_OFFLOAD_TCS;
378
379 if (num_tc == net_dev->num_tc)
380 return 0;
381
382 for (tc = 0; tc < num_tc; tc++) {
383 net_dev->tc_to_txq[tc].offset = tc * efx->n_tx_channels;
384 net_dev->tc_to_txq[tc].count = efx->n_tx_channels;
385 }
386
387 net_dev->num_tc = num_tc;
388
389 return netif_set_real_num_tx_queues(dev: net_dev,
390 max_t(int, num_tc, 1) *
391 efx->n_tx_channels);
392}
393

source code of linux/drivers/net/ethernet/sfc/siena/tx.c