1 // SPDX-License-Identifier: GPL-2.0-only
2 /****************************************************************************
3  * Driver for Solarflare network controllers and boards
4  * Copyright 2018 Solarflare Communications Inc.
5  *
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.
9  */
10 
11 #include "net_driver.h"
12 #include <linux/module.h>
13 #include "efx_channels.h"
14 #include "efx.h"
15 #include "efx_common.h"
16 #include "tx_common.h"
17 #include "rx_common.h"
18 #include "nic.h"
19 #include "sriov.h"
20 
21 /* This is the first interrupt mode to try out of:
22  * 0 => MSI-X
23  * 1 => MSI
24  * 2 => legacy
25  */
26 static unsigned int interrupt_mode;
27 module_param(interrupt_mode, uint, 0444);
28 MODULE_PARM_DESC(interrupt_mode,
29 		 "Interrupt mode (0=>MSIX 1=>MSI 2=>legacy)");
30 
31 /* This is the requested number of CPUs to use for Receive-Side Scaling (RSS),
32  * i.e. the number of CPUs among which we may distribute simultaneous
33  * interrupt handling.
34  *
35  * Cards without MSI-X will only target one CPU via legacy or MSI interrupt.
36  * The default (0) means to assign an interrupt to each core.
37  */
38 static unsigned int rss_cpus;
39 module_param(rss_cpus, uint, 0444);
40 MODULE_PARM_DESC(rss_cpus, "Number of CPUs to use for Receive-Side Scaling");
41 
42 static unsigned int irq_adapt_low_thresh = 8000;
43 module_param(irq_adapt_low_thresh, uint, 0644);
44 MODULE_PARM_DESC(irq_adapt_low_thresh,
45 		 "Threshold score for reducing IRQ moderation");
46 
47 static unsigned int irq_adapt_high_thresh = 16000;
48 module_param(irq_adapt_high_thresh, uint, 0644);
49 MODULE_PARM_DESC(irq_adapt_high_thresh,
50 		 "Threshold score for increasing IRQ moderation");
51 
52 /* This is the weight assigned to each of the (per-channel) virtual
53  * NAPI devices.
54  */
55 static int napi_weight = 64;
56 
57 /***************
58  * Housekeeping
59  ***************/
60 
61 int efx_channel_dummy_op_int(struct efx_channel *channel)
62 {
63 	return 0;
64 }
65 
66 void efx_channel_dummy_op_void(struct efx_channel *channel)
67 {
68 }
69 
70 static const struct efx_channel_type efx_default_channel_type = {
71 	.pre_probe		= efx_channel_dummy_op_int,
72 	.post_remove		= efx_channel_dummy_op_void,
73 	.get_name		= efx_get_channel_name,
74 	.copy			= efx_copy_channel,
75 	.want_txqs		= efx_default_channel_want_txqs,
76 	.keep_eventq		= false,
77 	.want_pio		= true,
78 };
79 
80 /*************
81  * INTERRUPTS
82  *************/
83 
84 static unsigned int efx_wanted_parallelism(struct efx_nic *efx)
85 {
86 	cpumask_var_t thread_mask;
87 	unsigned int count;
88 	int cpu;
89 
90 	if (rss_cpus) {
91 		count = rss_cpus;
92 	} else {
93 		if (unlikely(!zalloc_cpumask_var(&thread_mask, GFP_KERNEL))) {
94 			netif_warn(efx, probe, efx->net_dev,
95 				   "RSS disabled due to allocation failure\n");
96 			return 1;
97 		}
98 
99 		count = 0;
100 		for_each_online_cpu(cpu) {
101 			if (!cpumask_test_cpu(cpu, thread_mask)) {
102 				++count;
103 				cpumask_or(thread_mask, thread_mask,
104 					   topology_sibling_cpumask(cpu));
105 			}
106 		}
107 
108 		free_cpumask_var(thread_mask);
109 	}
110 
111 	if (count > EFX_MAX_RX_QUEUES) {
112 		netif_cond_dbg(efx, probe, efx->net_dev, !rss_cpus, warn,
113 			       "Reducing number of rx queues from %u to %u.\n",
114 			       count, EFX_MAX_RX_QUEUES);
115 		count = EFX_MAX_RX_QUEUES;
116 	}
117 
118 	/* If RSS is requested for the PF *and* VFs then we can't write RSS
119 	 * table entries that are inaccessible to VFs
120 	 */
121 #ifdef CONFIG_SFC_SRIOV
122 	if (efx->type->sriov_wanted) {
123 		if (efx->type->sriov_wanted(efx) && efx_vf_size(efx) > 1 &&
124 		    count > efx_vf_size(efx)) {
125 			netif_warn(efx, probe, efx->net_dev,
126 				   "Reducing number of RSS channels from %u to %u for "
127 				   "VF support. Increase vf-msix-limit to use more "
128 				   "channels on the PF.\n",
129 				   count, efx_vf_size(efx));
130 			count = efx_vf_size(efx);
131 		}
132 	}
133 #endif
134 
135 	return count;
136 }
137 
138 static int efx_allocate_msix_channels(struct efx_nic *efx,
139 				      unsigned int max_channels,
140 				      unsigned int extra_channels,
141 				      unsigned int parallelism)
142 {
143 	unsigned int n_channels = parallelism;
144 	int vec_count;
145 	int n_xdp_tx;
146 	int n_xdp_ev;
147 
148 	if (efx_separate_tx_channels)
149 		n_channels *= 2;
150 	n_channels += extra_channels;
151 
152 	/* To allow XDP transmit to happen from arbitrary NAPI contexts
153 	 * we allocate a TX queue per CPU. We share event queues across
154 	 * multiple tx queues, assuming tx and ev queues are both
155 	 * maximum size.
156 	 */
157 
158 	n_xdp_tx = num_possible_cpus();
159 	n_xdp_ev = DIV_ROUND_UP(n_xdp_tx, EFX_TXQ_TYPES);
160 
161 	vec_count = pci_msix_vec_count(efx->pci_dev);
162 	if (vec_count < 0)
163 		return vec_count;
164 
165 	max_channels = min_t(unsigned int, vec_count, max_channels);
166 
167 	/* Check resources.
168 	 * We need a channel per event queue, plus a VI per tx queue.
169 	 * This may be more pessimistic than it needs to be.
170 	 */
171 	if (n_channels + n_xdp_ev > max_channels) {
172 		netif_err(efx, drv, efx->net_dev,
173 			  "Insufficient resources for %d XDP event queues (%d other channels, max %d)\n",
174 			  n_xdp_ev, n_channels, max_channels);
175 		efx->n_xdp_channels = 0;
176 		efx->xdp_tx_per_channel = 0;
177 		efx->xdp_tx_queue_count = 0;
178 	} else {
179 		efx->n_xdp_channels = n_xdp_ev;
180 		efx->xdp_tx_per_channel = EFX_TXQ_TYPES;
181 		efx->xdp_tx_queue_count = n_xdp_tx;
182 		n_channels += n_xdp_ev;
183 		netif_dbg(efx, drv, efx->net_dev,
184 			  "Allocating %d TX and %d event queues for XDP\n",
185 			  n_xdp_tx, n_xdp_ev);
186 	}
187 
188 	if (vec_count < n_channels) {
189 		netif_err(efx, drv, efx->net_dev,
190 			  "WARNING: Insufficient MSI-X vectors available (%d < %u).\n",
191 			  vec_count, n_channels);
192 		netif_err(efx, drv, efx->net_dev,
193 			  "WARNING: Performance may be reduced.\n");
194 		n_channels = vec_count;
195 	}
196 
197 	n_channels = min(n_channels, max_channels);
198 
199 	efx->n_channels = n_channels;
200 
201 	/* Ignore XDP tx channels when creating rx channels. */
202 	n_channels -= efx->n_xdp_channels;
203 
204 	if (efx_separate_tx_channels) {
205 		efx->n_tx_channels =
206 			min(max(n_channels / 2, 1U),
207 			    efx->max_tx_channels);
208 		efx->tx_channel_offset =
209 			n_channels - efx->n_tx_channels;
210 		efx->n_rx_channels =
211 			max(n_channels -
212 			    efx->n_tx_channels, 1U);
213 	} else {
214 		efx->n_tx_channels = min(n_channels, efx->max_tx_channels);
215 		efx->tx_channel_offset = 0;
216 		efx->n_rx_channels = n_channels;
217 	}
218 
219 	efx->n_rx_channels = min(efx->n_rx_channels, parallelism);
220 	efx->n_tx_channels = min(efx->n_tx_channels, parallelism);
221 
222 	efx->xdp_channel_offset = n_channels;
223 
224 	netif_dbg(efx, drv, efx->net_dev,
225 		  "Allocating %u RX channels\n",
226 		  efx->n_rx_channels);
227 
228 	return efx->n_channels;
229 }
230 
231 /* Probe the number and type of interrupts we are able to obtain, and
232  * the resulting numbers of channels and RX queues.
233  */
234 int efx_probe_interrupts(struct efx_nic *efx)
235 {
236 	unsigned int extra_channels = 0;
237 	unsigned int rss_spread;
238 	unsigned int i, j;
239 	int rc;
240 
241 	for (i = 0; i < EFX_MAX_EXTRA_CHANNELS; i++)
242 		if (efx->extra_channel_type[i])
243 			++extra_channels;
244 
245 	if (efx->interrupt_mode == EFX_INT_MODE_MSIX) {
246 		unsigned int parallelism = efx_wanted_parallelism(efx);
247 		struct msix_entry xentries[EFX_MAX_CHANNELS];
248 		unsigned int n_channels;
249 
250 		rc = efx_allocate_msix_channels(efx, efx->max_channels,
251 						extra_channels, parallelism);
252 		if (rc >= 0) {
253 			n_channels = rc;
254 			for (i = 0; i < n_channels; i++)
255 				xentries[i].entry = i;
256 			rc = pci_enable_msix_range(efx->pci_dev, xentries, 1,
257 						   n_channels);
258 		}
259 		if (rc < 0) {
260 			/* Fall back to single channel MSI */
261 			netif_err(efx, drv, efx->net_dev,
262 				  "could not enable MSI-X\n");
263 			if (efx->type->min_interrupt_mode >= EFX_INT_MODE_MSI)
264 				efx->interrupt_mode = EFX_INT_MODE_MSI;
265 			else
266 				return rc;
267 		} else if (rc < n_channels) {
268 			netif_err(efx, drv, efx->net_dev,
269 				  "WARNING: Insufficient MSI-X vectors"
270 				  " available (%d < %u).\n", rc, n_channels);
271 			netif_err(efx, drv, efx->net_dev,
272 				  "WARNING: Performance may be reduced.\n");
273 			n_channels = rc;
274 		}
275 
276 		if (rc > 0) {
277 			for (i = 0; i < efx->n_channels; i++)
278 				efx_get_channel(efx, i)->irq =
279 					xentries[i].vector;
280 		}
281 	}
282 
283 	/* Try single interrupt MSI */
284 	if (efx->interrupt_mode == EFX_INT_MODE_MSI) {
285 		efx->n_channels = 1;
286 		efx->n_rx_channels = 1;
287 		efx->n_tx_channels = 1;
288 		efx->n_xdp_channels = 0;
289 		efx->xdp_channel_offset = efx->n_channels;
290 		rc = pci_enable_msi(efx->pci_dev);
291 		if (rc == 0) {
292 			efx_get_channel(efx, 0)->irq = efx->pci_dev->irq;
293 		} else {
294 			netif_err(efx, drv, efx->net_dev,
295 				  "could not enable MSI\n");
296 			if (efx->type->min_interrupt_mode >= EFX_INT_MODE_LEGACY)
297 				efx->interrupt_mode = EFX_INT_MODE_LEGACY;
298 			else
299 				return rc;
300 		}
301 	}
302 
303 	/* Assume legacy interrupts */
304 	if (efx->interrupt_mode == EFX_INT_MODE_LEGACY) {
305 		efx->n_channels = 1 + (efx_separate_tx_channels ? 1 : 0);
306 		efx->n_rx_channels = 1;
307 		efx->n_tx_channels = 1;
308 		efx->n_xdp_channels = 0;
309 		efx->xdp_channel_offset = efx->n_channels;
310 		efx->legacy_irq = efx->pci_dev->irq;
311 	}
312 
313 	/* Assign extra channels if possible, before XDP channels */
314 	efx->n_extra_tx_channels = 0;
315 	j = efx->xdp_channel_offset;
316 	for (i = 0; i < EFX_MAX_EXTRA_CHANNELS; i++) {
317 		if (!efx->extra_channel_type[i])
318 			continue;
319 		if (j <= efx->tx_channel_offset + efx->n_tx_channels) {
320 			efx->extra_channel_type[i]->handle_no_channel(efx);
321 		} else {
322 			--j;
323 			efx_get_channel(efx, j)->type =
324 				efx->extra_channel_type[i];
325 			if (efx_channel_has_tx_queues(efx_get_channel(efx, j)))
326 				efx->n_extra_tx_channels++;
327 		}
328 	}
329 
330 	rss_spread = efx->n_rx_channels;
331 	/* RSS might be usable on VFs even if it is disabled on the PF */
332 #ifdef CONFIG_SFC_SRIOV
333 	if (efx->type->sriov_wanted) {
334 		efx->rss_spread = ((rss_spread > 1 ||
335 				    !efx->type->sriov_wanted(efx)) ?
336 				   rss_spread : efx_vf_size(efx));
337 		return 0;
338 	}
339 #endif
340 	efx->rss_spread = rss_spread;
341 
342 	return 0;
343 }
344 
345 #if defined(CONFIG_SMP)
346 void efx_set_interrupt_affinity(struct efx_nic *efx)
347 {
348 	struct efx_channel *channel;
349 	unsigned int cpu;
350 
351 	efx_for_each_channel(channel, efx) {
352 		cpu = cpumask_local_spread(channel->channel,
353 					   pcibus_to_node(efx->pci_dev->bus));
354 		irq_set_affinity_hint(channel->irq, cpumask_of(cpu));
355 	}
356 }
357 
358 void efx_clear_interrupt_affinity(struct efx_nic *efx)
359 {
360 	struct efx_channel *channel;
361 
362 	efx_for_each_channel(channel, efx)
363 		irq_set_affinity_hint(channel->irq, NULL);
364 }
365 #else
366 void
367 efx_set_interrupt_affinity(struct efx_nic *efx __attribute__ ((unused)))
368 {
369 }
370 
371 void
372 efx_clear_interrupt_affinity(struct efx_nic *efx __attribute__ ((unused)))
373 {
374 }
375 #endif /* CONFIG_SMP */
376 
377 void efx_remove_interrupts(struct efx_nic *efx)
378 {
379 	struct efx_channel *channel;
380 
381 	/* Remove MSI/MSI-X interrupts */
382 	efx_for_each_channel(channel, efx)
383 		channel->irq = 0;
384 	pci_disable_msi(efx->pci_dev);
385 	pci_disable_msix(efx->pci_dev);
386 
387 	/* Remove legacy interrupt */
388 	efx->legacy_irq = 0;
389 }
390 
391 /***************
392  * EVENT QUEUES
393  ***************/
394 
395 /* Create event queue
396  * Event queue memory allocations are done only once.  If the channel
397  * is reset, the memory buffer will be reused; this guards against
398  * errors during channel reset and also simplifies interrupt handling.
399  */
400 int efx_probe_eventq(struct efx_channel *channel)
401 {
402 	struct efx_nic *efx = channel->efx;
403 	unsigned long entries;
404 
405 	netif_dbg(efx, probe, efx->net_dev,
406 		  "chan %d create event queue\n", channel->channel);
407 
408 	/* Build an event queue with room for one event per tx and rx buffer,
409 	 * plus some extra for link state events and MCDI completions.
410 	 */
411 	entries = roundup_pow_of_two(efx->rxq_entries + efx->txq_entries + 128);
412 	EFX_WARN_ON_PARANOID(entries > EFX_MAX_EVQ_SIZE);
413 	channel->eventq_mask = max(entries, EFX_MIN_EVQ_SIZE) - 1;
414 
415 	return efx_nic_probe_eventq(channel);
416 }
417 
418 /* Prepare channel's event queue */
419 int efx_init_eventq(struct efx_channel *channel)
420 {
421 	struct efx_nic *efx = channel->efx;
422 	int rc;
423 
424 	EFX_WARN_ON_PARANOID(channel->eventq_init);
425 
426 	netif_dbg(efx, drv, efx->net_dev,
427 		  "chan %d init event queue\n", channel->channel);
428 
429 	rc = efx_nic_init_eventq(channel);
430 	if (rc == 0) {
431 		efx->type->push_irq_moderation(channel);
432 		channel->eventq_read_ptr = 0;
433 		channel->eventq_init = true;
434 	}
435 	return rc;
436 }
437 
438 /* Enable event queue processing and NAPI */
439 void efx_start_eventq(struct efx_channel *channel)
440 {
441 	netif_dbg(channel->efx, ifup, channel->efx->net_dev,
442 		  "chan %d start event queue\n", channel->channel);
443 
444 	/* Make sure the NAPI handler sees the enabled flag set */
445 	channel->enabled = true;
446 	smp_wmb();
447 
448 	napi_enable(&channel->napi_str);
449 	efx_nic_eventq_read_ack(channel);
450 }
451 
452 /* Disable event queue processing and NAPI */
453 void efx_stop_eventq(struct efx_channel *channel)
454 {
455 	if (!channel->enabled)
456 		return;
457 
458 	napi_disable(&channel->napi_str);
459 	channel->enabled = false;
460 }
461 
462 void efx_fini_eventq(struct efx_channel *channel)
463 {
464 	if (!channel->eventq_init)
465 		return;
466 
467 	netif_dbg(channel->efx, drv, channel->efx->net_dev,
468 		  "chan %d fini event queue\n", channel->channel);
469 
470 	efx_nic_fini_eventq(channel);
471 	channel->eventq_init = false;
472 }
473 
474 void efx_remove_eventq(struct efx_channel *channel)
475 {
476 	netif_dbg(channel->efx, drv, channel->efx->net_dev,
477 		  "chan %d remove event queue\n", channel->channel);
478 
479 	efx_nic_remove_eventq(channel);
480 }
481 
482 /**************************************************************************
483  *
484  * Channel handling
485  *
486  *************************************************************************/
487 
488 /* Allocate and initialise a channel structure. */
489 struct efx_channel *
490 efx_alloc_channel(struct efx_nic *efx, int i, struct efx_channel *old_channel)
491 {
492 	struct efx_rx_queue *rx_queue;
493 	struct efx_tx_queue *tx_queue;
494 	struct efx_channel *channel;
495 	int j;
496 
497 	channel = kzalloc(sizeof(*channel), GFP_KERNEL);
498 	if (!channel)
499 		return NULL;
500 
501 	channel->efx = efx;
502 	channel->channel = i;
503 	channel->type = &efx_default_channel_type;
504 
505 	for (j = 0; j < EFX_TXQ_TYPES; j++) {
506 		tx_queue = &channel->tx_queue[j];
507 		tx_queue->efx = efx;
508 		tx_queue->queue = i * EFX_TXQ_TYPES + j;
509 		tx_queue->channel = channel;
510 	}
511 
512 #ifdef CONFIG_RFS_ACCEL
513 	INIT_DELAYED_WORK(&channel->filter_work, efx_filter_rfs_expire);
514 #endif
515 
516 	rx_queue = &channel->rx_queue;
517 	rx_queue->efx = efx;
518 	timer_setup(&rx_queue->slow_fill, efx_rx_slow_fill, 0);
519 
520 	return channel;
521 }
522 
523 int efx_init_channels(struct efx_nic *efx)
524 {
525 	unsigned int i;
526 
527 	for (i = 0; i < EFX_MAX_CHANNELS; i++) {
528 		efx->channel[i] = efx_alloc_channel(efx, i, NULL);
529 		if (!efx->channel[i])
530 			return -ENOMEM;
531 		efx->msi_context[i].efx = efx;
532 		efx->msi_context[i].index = i;
533 	}
534 
535 	/* Higher numbered interrupt modes are less capable! */
536 	if (WARN_ON_ONCE(efx->type->max_interrupt_mode >
537 			 efx->type->min_interrupt_mode)) {
538 		return -EIO;
539 	}
540 	efx->interrupt_mode = max(efx->type->max_interrupt_mode,
541 				  interrupt_mode);
542 	efx->interrupt_mode = min(efx->type->min_interrupt_mode,
543 				  interrupt_mode);
544 
545 	return 0;
546 }
547 
548 void efx_fini_channels(struct efx_nic *efx)
549 {
550 	unsigned int i;
551 
552 	for (i = 0; i < EFX_MAX_CHANNELS; i++)
553 		if (efx->channel[i]) {
554 			kfree(efx->channel[i]);
555 			efx->channel[i] = NULL;
556 		}
557 }
558 
559 /* Allocate and initialise a channel structure, copying parameters
560  * (but not resources) from an old channel structure.
561  */
562 struct efx_channel *efx_copy_channel(const struct efx_channel *old_channel)
563 {
564 	struct efx_rx_queue *rx_queue;
565 	struct efx_tx_queue *tx_queue;
566 	struct efx_channel *channel;
567 	int j;
568 
569 	channel = kmalloc(sizeof(*channel), GFP_KERNEL);
570 	if (!channel)
571 		return NULL;
572 
573 	*channel = *old_channel;
574 
575 	channel->napi_dev = NULL;
576 	INIT_HLIST_NODE(&channel->napi_str.napi_hash_node);
577 	channel->napi_str.napi_id = 0;
578 	channel->napi_str.state = 0;
579 	memset(&channel->eventq, 0, sizeof(channel->eventq));
580 
581 	for (j = 0; j < EFX_TXQ_TYPES; j++) {
582 		tx_queue = &channel->tx_queue[j];
583 		if (tx_queue->channel)
584 			tx_queue->channel = channel;
585 		tx_queue->buffer = NULL;
586 		memset(&tx_queue->txd, 0, sizeof(tx_queue->txd));
587 	}
588 
589 	rx_queue = &channel->rx_queue;
590 	rx_queue->buffer = NULL;
591 	memset(&rx_queue->rxd, 0, sizeof(rx_queue->rxd));
592 	timer_setup(&rx_queue->slow_fill, efx_rx_slow_fill, 0);
593 #ifdef CONFIG_RFS_ACCEL
594 	INIT_DELAYED_WORK(&channel->filter_work, efx_filter_rfs_expire);
595 #endif
596 
597 	return channel;
598 }
599 
600 static int efx_probe_channel(struct efx_channel *channel)
601 {
602 	struct efx_tx_queue *tx_queue;
603 	struct efx_rx_queue *rx_queue;
604 	int rc;
605 
606 	netif_dbg(channel->efx, probe, channel->efx->net_dev,
607 		  "creating channel %d\n", channel->channel);
608 
609 	rc = channel->type->pre_probe(channel);
610 	if (rc)
611 		goto fail;
612 
613 	rc = efx_probe_eventq(channel);
614 	if (rc)
615 		goto fail;
616 
617 	efx_for_each_channel_tx_queue(tx_queue, channel) {
618 		rc = efx_probe_tx_queue(tx_queue);
619 		if (rc)
620 			goto fail;
621 	}
622 
623 	efx_for_each_channel_rx_queue(rx_queue, channel) {
624 		rc = efx_probe_rx_queue(rx_queue);
625 		if (rc)
626 			goto fail;
627 	}
628 
629 	channel->rx_list = NULL;
630 
631 	return 0;
632 
633 fail:
634 	efx_remove_channel(channel);
635 	return rc;
636 }
637 
638 void efx_get_channel_name(struct efx_channel *channel, char *buf, size_t len)
639 {
640 	struct efx_nic *efx = channel->efx;
641 	const char *type;
642 	int number;
643 
644 	number = channel->channel;
645 
646 	if (number >= efx->xdp_channel_offset &&
647 	    !WARN_ON_ONCE(!efx->n_xdp_channels)) {
648 		type = "-xdp";
649 		number -= efx->xdp_channel_offset;
650 	} else if (efx->tx_channel_offset == 0) {
651 		type = "";
652 	} else if (number < efx->tx_channel_offset) {
653 		type = "-rx";
654 	} else {
655 		type = "-tx";
656 		number -= efx->tx_channel_offset;
657 	}
658 	snprintf(buf, len, "%s%s-%d", efx->name, type, number);
659 }
660 
661 void efx_set_channel_names(struct efx_nic *efx)
662 {
663 	struct efx_channel *channel;
664 
665 	efx_for_each_channel(channel, efx)
666 		channel->type->get_name(channel,
667 					efx->msi_context[channel->channel].name,
668 					sizeof(efx->msi_context[0].name));
669 }
670 
671 int efx_probe_channels(struct efx_nic *efx)
672 {
673 	struct efx_channel *channel;
674 	int rc;
675 
676 	/* Restart special buffer allocation */
677 	efx->next_buffer_table = 0;
678 
679 	/* Probe channels in reverse, so that any 'extra' channels
680 	 * use the start of the buffer table. This allows the traffic
681 	 * channels to be resized without moving them or wasting the
682 	 * entries before them.
683 	 */
684 	efx_for_each_channel_rev(channel, efx) {
685 		rc = efx_probe_channel(channel);
686 		if (rc) {
687 			netif_err(efx, probe, efx->net_dev,
688 				  "failed to create channel %d\n",
689 				  channel->channel);
690 			goto fail;
691 		}
692 	}
693 	efx_set_channel_names(efx);
694 
695 	return 0;
696 
697 fail:
698 	efx_remove_channels(efx);
699 	return rc;
700 }
701 
702 void efx_remove_channel(struct efx_channel *channel)
703 {
704 	struct efx_tx_queue *tx_queue;
705 	struct efx_rx_queue *rx_queue;
706 
707 	netif_dbg(channel->efx, drv, channel->efx->net_dev,
708 		  "destroy chan %d\n", channel->channel);
709 
710 	efx_for_each_channel_rx_queue(rx_queue, channel)
711 		efx_remove_rx_queue(rx_queue);
712 	efx_for_each_possible_channel_tx_queue(tx_queue, channel)
713 		efx_remove_tx_queue(tx_queue);
714 	efx_remove_eventq(channel);
715 	channel->type->post_remove(channel);
716 }
717 
718 void efx_remove_channels(struct efx_nic *efx)
719 {
720 	struct efx_channel *channel;
721 
722 	efx_for_each_channel(channel, efx)
723 		efx_remove_channel(channel);
724 
725 	kfree(efx->xdp_tx_queues);
726 }
727 
728 int efx_realloc_channels(struct efx_nic *efx, u32 rxq_entries, u32 txq_entries)
729 {
730 	struct efx_channel *other_channel[EFX_MAX_CHANNELS], *channel;
731 	unsigned int i, next_buffer_table = 0;
732 	u32 old_rxq_entries, old_txq_entries;
733 	int rc, rc2;
734 
735 	rc = efx_check_disabled(efx);
736 	if (rc)
737 		return rc;
738 
739 	/* Not all channels should be reallocated. We must avoid
740 	 * reallocating their buffer table entries.
741 	 */
742 	efx_for_each_channel(channel, efx) {
743 		struct efx_rx_queue *rx_queue;
744 		struct efx_tx_queue *tx_queue;
745 
746 		if (channel->type->copy)
747 			continue;
748 		next_buffer_table = max(next_buffer_table,
749 					channel->eventq.index +
750 					channel->eventq.entries);
751 		efx_for_each_channel_rx_queue(rx_queue, channel)
752 			next_buffer_table = max(next_buffer_table,
753 						rx_queue->rxd.index +
754 						rx_queue->rxd.entries);
755 		efx_for_each_channel_tx_queue(tx_queue, channel)
756 			next_buffer_table = max(next_buffer_table,
757 						tx_queue->txd.index +
758 						tx_queue->txd.entries);
759 	}
760 
761 	efx_device_detach_sync(efx);
762 	efx_stop_all(efx);
763 	efx_soft_disable_interrupts(efx);
764 
765 	/* Clone channels (where possible) */
766 	memset(other_channel, 0, sizeof(other_channel));
767 	for (i = 0; i < efx->n_channels; i++) {
768 		channel = efx->channel[i];
769 		if (channel->type->copy)
770 			channel = channel->type->copy(channel);
771 		if (!channel) {
772 			rc = -ENOMEM;
773 			goto out;
774 		}
775 		other_channel[i] = channel;
776 	}
777 
778 	/* Swap entry counts and channel pointers */
779 	old_rxq_entries = efx->rxq_entries;
780 	old_txq_entries = efx->txq_entries;
781 	efx->rxq_entries = rxq_entries;
782 	efx->txq_entries = txq_entries;
783 	for (i = 0; i < efx->n_channels; i++) {
784 		channel = efx->channel[i];
785 		efx->channel[i] = other_channel[i];
786 		other_channel[i] = channel;
787 	}
788 
789 	/* Restart buffer table allocation */
790 	efx->next_buffer_table = next_buffer_table;
791 
792 	for (i = 0; i < efx->n_channels; i++) {
793 		channel = efx->channel[i];
794 		if (!channel->type->copy)
795 			continue;
796 		rc = efx_probe_channel(channel);
797 		if (rc)
798 			goto rollback;
799 		efx_init_napi_channel(efx->channel[i]);
800 	}
801 
802 out:
803 	/* Destroy unused channel structures */
804 	for (i = 0; i < efx->n_channels; i++) {
805 		channel = other_channel[i];
806 		if (channel && channel->type->copy) {
807 			efx_fini_napi_channel(channel);
808 			efx_remove_channel(channel);
809 			kfree(channel);
810 		}
811 	}
812 
813 	rc2 = efx_soft_enable_interrupts(efx);
814 	if (rc2) {
815 		rc = rc ? rc : rc2;
816 		netif_err(efx, drv, efx->net_dev,
817 			  "unable to restart interrupts on channel reallocation\n");
818 		efx_schedule_reset(efx, RESET_TYPE_DISABLE);
819 	} else {
820 		efx_start_all(efx);
821 		efx_device_attach_if_not_resetting(efx);
822 	}
823 	return rc;
824 
825 rollback:
826 	/* Swap back */
827 	efx->rxq_entries = old_rxq_entries;
828 	efx->txq_entries = old_txq_entries;
829 	for (i = 0; i < efx->n_channels; i++) {
830 		channel = efx->channel[i];
831 		efx->channel[i] = other_channel[i];
832 		other_channel[i] = channel;
833 	}
834 	goto out;
835 }
836 
837 int efx_set_channels(struct efx_nic *efx)
838 {
839 	struct efx_channel *channel;
840 	struct efx_tx_queue *tx_queue;
841 	int xdp_queue_number;
842 
843 	efx->tx_channel_offset =
844 		efx_separate_tx_channels ?
845 		efx->n_channels - efx->n_tx_channels : 0;
846 
847 	if (efx->xdp_tx_queue_count) {
848 		EFX_WARN_ON_PARANOID(efx->xdp_tx_queues);
849 
850 		/* Allocate array for XDP TX queue lookup. */
851 		efx->xdp_tx_queues = kcalloc(efx->xdp_tx_queue_count,
852 					     sizeof(*efx->xdp_tx_queues),
853 					     GFP_KERNEL);
854 		if (!efx->xdp_tx_queues)
855 			return -ENOMEM;
856 	}
857 
858 	/* We need to mark which channels really have RX and TX
859 	 * queues, and adjust the TX queue numbers if we have separate
860 	 * RX-only and TX-only channels.
861 	 */
862 	xdp_queue_number = 0;
863 	efx_for_each_channel(channel, efx) {
864 		if (channel->channel < efx->n_rx_channels)
865 			channel->rx_queue.core_index = channel->channel;
866 		else
867 			channel->rx_queue.core_index = -1;
868 
869 		efx_for_each_channel_tx_queue(tx_queue, channel) {
870 			tx_queue->queue -= (efx->tx_channel_offset *
871 					    EFX_TXQ_TYPES);
872 
873 			if (efx_channel_is_xdp_tx(channel) &&
874 			    xdp_queue_number < efx->xdp_tx_queue_count) {
875 				efx->xdp_tx_queues[xdp_queue_number] = tx_queue;
876 				xdp_queue_number++;
877 			}
878 		}
879 	}
880 	return 0;
881 }
882 
883 bool efx_default_channel_want_txqs(struct efx_channel *channel)
884 {
885 	return channel->channel - channel->efx->tx_channel_offset <
886 		channel->efx->n_tx_channels;
887 }
888 
889 /*************
890  * START/STOP
891  *************/
892 
893 int efx_soft_enable_interrupts(struct efx_nic *efx)
894 {
895 	struct efx_channel *channel, *end_channel;
896 	int rc;
897 
898 	BUG_ON(efx->state == STATE_DISABLED);
899 
900 	efx->irq_soft_enabled = true;
901 	smp_wmb();
902 
903 	efx_for_each_channel(channel, efx) {
904 		if (!channel->type->keep_eventq) {
905 			rc = efx_init_eventq(channel);
906 			if (rc)
907 				goto fail;
908 		}
909 		efx_start_eventq(channel);
910 	}
911 
912 	efx_mcdi_mode_event(efx);
913 
914 	return 0;
915 fail:
916 	end_channel = channel;
917 	efx_for_each_channel(channel, efx) {
918 		if (channel == end_channel)
919 			break;
920 		efx_stop_eventq(channel);
921 		if (!channel->type->keep_eventq)
922 			efx_fini_eventq(channel);
923 	}
924 
925 	return rc;
926 }
927 
928 void efx_soft_disable_interrupts(struct efx_nic *efx)
929 {
930 	struct efx_channel *channel;
931 
932 	if (efx->state == STATE_DISABLED)
933 		return;
934 
935 	efx_mcdi_mode_poll(efx);
936 
937 	efx->irq_soft_enabled = false;
938 	smp_wmb();
939 
940 	if (efx->legacy_irq)
941 		synchronize_irq(efx->legacy_irq);
942 
943 	efx_for_each_channel(channel, efx) {
944 		if (channel->irq)
945 			synchronize_irq(channel->irq);
946 
947 		efx_stop_eventq(channel);
948 		if (!channel->type->keep_eventq)
949 			efx_fini_eventq(channel);
950 	}
951 
952 	/* Flush the asynchronous MCDI request queue */
953 	efx_mcdi_flush_async(efx);
954 }
955 
956 int efx_enable_interrupts(struct efx_nic *efx)
957 {
958 	struct efx_channel *channel, *end_channel;
959 	int rc;
960 
961 	/* TODO: Is this really a bug? */
962 	BUG_ON(efx->state == STATE_DISABLED);
963 
964 	if (efx->eeh_disabled_legacy_irq) {
965 		enable_irq(efx->legacy_irq);
966 		efx->eeh_disabled_legacy_irq = false;
967 	}
968 
969 	efx->type->irq_enable_master(efx);
970 
971 	efx_for_each_channel(channel, efx) {
972 		if (channel->type->keep_eventq) {
973 			rc = efx_init_eventq(channel);
974 			if (rc)
975 				goto fail;
976 		}
977 	}
978 
979 	rc = efx_soft_enable_interrupts(efx);
980 	if (rc)
981 		goto fail;
982 
983 	return 0;
984 
985 fail:
986 	end_channel = channel;
987 	efx_for_each_channel(channel, efx) {
988 		if (channel == end_channel)
989 			break;
990 		if (channel->type->keep_eventq)
991 			efx_fini_eventq(channel);
992 	}
993 
994 	efx->type->irq_disable_non_ev(efx);
995 
996 	return rc;
997 }
998 
999 void efx_disable_interrupts(struct efx_nic *efx)
1000 {
1001 	struct efx_channel *channel;
1002 
1003 	efx_soft_disable_interrupts(efx);
1004 
1005 	efx_for_each_channel(channel, efx) {
1006 		if (channel->type->keep_eventq)
1007 			efx_fini_eventq(channel);
1008 	}
1009 
1010 	efx->type->irq_disable_non_ev(efx);
1011 }
1012 
1013 void efx_start_channels(struct efx_nic *efx)
1014 {
1015 	struct efx_tx_queue *tx_queue;
1016 	struct efx_rx_queue *rx_queue;
1017 	struct efx_channel *channel;
1018 
1019 	efx_for_each_channel(channel, efx) {
1020 		efx_for_each_channel_tx_queue(tx_queue, channel) {
1021 			efx_init_tx_queue(tx_queue);
1022 			atomic_inc(&efx->active_queues);
1023 		}
1024 
1025 		efx_for_each_channel_rx_queue(rx_queue, channel) {
1026 			efx_init_rx_queue(rx_queue);
1027 			atomic_inc(&efx->active_queues);
1028 			efx_stop_eventq(channel);
1029 			efx_fast_push_rx_descriptors(rx_queue, false);
1030 			efx_start_eventq(channel);
1031 		}
1032 
1033 		WARN_ON(channel->rx_pkt_n_frags);
1034 	}
1035 }
1036 
1037 void efx_stop_channels(struct efx_nic *efx)
1038 {
1039 	struct efx_tx_queue *tx_queue;
1040 	struct efx_rx_queue *rx_queue;
1041 	struct efx_channel *channel;
1042 	int rc = 0;
1043 
1044 	/* Stop RX refill */
1045 	efx_for_each_channel(channel, efx) {
1046 		efx_for_each_channel_rx_queue(rx_queue, channel)
1047 			rx_queue->refill_enabled = false;
1048 	}
1049 
1050 	efx_for_each_channel(channel, efx) {
1051 		/* RX packet processing is pipelined, so wait for the
1052 		 * NAPI handler to complete.  At least event queue 0
1053 		 * might be kept active by non-data events, so don't
1054 		 * use napi_synchronize() but actually disable NAPI
1055 		 * temporarily.
1056 		 */
1057 		if (efx_channel_has_rx_queue(channel)) {
1058 			efx_stop_eventq(channel);
1059 			efx_start_eventq(channel);
1060 		}
1061 	}
1062 
1063 	if (efx->type->fini_dmaq)
1064 		rc = efx->type->fini_dmaq(efx);
1065 
1066 	if (rc) {
1067 		netif_err(efx, drv, efx->net_dev, "failed to flush queues\n");
1068 	} else {
1069 		netif_dbg(efx, drv, efx->net_dev,
1070 			  "successfully flushed all queues\n");
1071 	}
1072 
1073 	efx_for_each_channel(channel, efx) {
1074 		efx_for_each_channel_rx_queue(rx_queue, channel)
1075 			efx_fini_rx_queue(rx_queue);
1076 		efx_for_each_possible_channel_tx_queue(tx_queue, channel)
1077 			efx_fini_tx_queue(tx_queue);
1078 	}
1079 }
1080 
1081 /**************************************************************************
1082  *
1083  * NAPI interface
1084  *
1085  *************************************************************************/
1086 
1087 /* Process channel's event queue
1088  *
1089  * This function is responsible for processing the event queue of a
1090  * single channel.  The caller must guarantee that this function will
1091  * never be concurrently called more than once on the same channel,
1092  * though different channels may be being processed concurrently.
1093  */
1094 static int efx_process_channel(struct efx_channel *channel, int budget)
1095 {
1096 	struct efx_tx_queue *tx_queue;
1097 	struct list_head rx_list;
1098 	int spent;
1099 
1100 	if (unlikely(!channel->enabled))
1101 		return 0;
1102 
1103 	/* Prepare the batch receive list */
1104 	EFX_WARN_ON_PARANOID(channel->rx_list != NULL);
1105 	INIT_LIST_HEAD(&rx_list);
1106 	channel->rx_list = &rx_list;
1107 
1108 	efx_for_each_channel_tx_queue(tx_queue, channel) {
1109 		tx_queue->pkts_compl = 0;
1110 		tx_queue->bytes_compl = 0;
1111 	}
1112 
1113 	spent = efx_nic_process_eventq(channel, budget);
1114 	if (spent && efx_channel_has_rx_queue(channel)) {
1115 		struct efx_rx_queue *rx_queue =
1116 			efx_channel_get_rx_queue(channel);
1117 
1118 		efx_rx_flush_packet(channel);
1119 		efx_fast_push_rx_descriptors(rx_queue, true);
1120 	}
1121 
1122 	/* Update BQL */
1123 	efx_for_each_channel_tx_queue(tx_queue, channel) {
1124 		if (tx_queue->bytes_compl) {
1125 			netdev_tx_completed_queue(tx_queue->core_txq,
1126 						  tx_queue->pkts_compl,
1127 						  tx_queue->bytes_compl);
1128 		}
1129 	}
1130 
1131 	/* Receive any packets we queued up */
1132 	netif_receive_skb_list(channel->rx_list);
1133 	channel->rx_list = NULL;
1134 
1135 	return spent;
1136 }
1137 
1138 static void efx_update_irq_mod(struct efx_nic *efx, struct efx_channel *channel)
1139 {
1140 	int step = efx->irq_mod_step_us;
1141 
1142 	if (channel->irq_mod_score < irq_adapt_low_thresh) {
1143 		if (channel->irq_moderation_us > step) {
1144 			channel->irq_moderation_us -= step;
1145 			efx->type->push_irq_moderation(channel);
1146 		}
1147 	} else if (channel->irq_mod_score > irq_adapt_high_thresh) {
1148 		if (channel->irq_moderation_us <
1149 		    efx->irq_rx_moderation_us) {
1150 			channel->irq_moderation_us += step;
1151 			efx->type->push_irq_moderation(channel);
1152 		}
1153 	}
1154 
1155 	channel->irq_count = 0;
1156 	channel->irq_mod_score = 0;
1157 }
1158 
1159 /* NAPI poll handler
1160  *
1161  * NAPI guarantees serialisation of polls of the same device, which
1162  * provides the guarantee required by efx_process_channel().
1163  */
1164 static int efx_poll(struct napi_struct *napi, int budget)
1165 {
1166 	struct efx_channel *channel =
1167 		container_of(napi, struct efx_channel, napi_str);
1168 	struct efx_nic *efx = channel->efx;
1169 	int spent;
1170 
1171 	netif_vdbg(efx, intr, efx->net_dev,
1172 		   "channel %d NAPI poll executing on CPU %d\n",
1173 		   channel->channel, raw_smp_processor_id());
1174 
1175 	spent = efx_process_channel(channel, budget);
1176 
1177 	xdp_do_flush_map();
1178 
1179 	if (spent < budget) {
1180 		if (efx_channel_has_rx_queue(channel) &&
1181 		    efx->irq_rx_adaptive &&
1182 		    unlikely(++channel->irq_count == 1000)) {
1183 			efx_update_irq_mod(efx, channel);
1184 		}
1185 
1186 #ifdef CONFIG_RFS_ACCEL
1187 		/* Perhaps expire some ARFS filters */
1188 		mod_delayed_work(system_wq, &channel->filter_work, 0);
1189 #endif
1190 
1191 		/* There is no race here; although napi_disable() will
1192 		 * only wait for napi_complete(), this isn't a problem
1193 		 * since efx_nic_eventq_read_ack() will have no effect if
1194 		 * interrupts have already been disabled.
1195 		 */
1196 		if (napi_complete_done(napi, spent))
1197 			efx_nic_eventq_read_ack(channel);
1198 	}
1199 
1200 	return spent;
1201 }
1202 
1203 void efx_init_napi_channel(struct efx_channel *channel)
1204 {
1205 	struct efx_nic *efx = channel->efx;
1206 
1207 	channel->napi_dev = efx->net_dev;
1208 	netif_napi_add(channel->napi_dev, &channel->napi_str,
1209 		       efx_poll, napi_weight);
1210 }
1211 
1212 void efx_init_napi(struct efx_nic *efx)
1213 {
1214 	struct efx_channel *channel;
1215 
1216 	efx_for_each_channel(channel, efx)
1217 		efx_init_napi_channel(channel);
1218 }
1219 
1220 void efx_fini_napi_channel(struct efx_channel *channel)
1221 {
1222 	if (channel->napi_dev)
1223 		netif_napi_del(&channel->napi_str);
1224 
1225 	channel->napi_dev = NULL;
1226 }
1227 
1228 void efx_fini_napi(struct efx_nic *efx)
1229 {
1230 	struct efx_channel *channel;
1231 
1232 	efx_for_each_channel(channel, efx)
1233 		efx_fini_napi_channel(channel);
1234 }
1235