1 /*
2  * aQuantia Corporation Network Driver
3  * Copyright (C) 2014-2017 aQuantia Corporation. All rights reserved
4  *
5  * This program is free software; you can redistribute it and/or modify it
6  * under the terms and conditions of the GNU General Public License,
7  * version 2, as published by the Free Software Foundation.
8  */
9 
10 /* File aq_ring.c: Definition of functions for Rx/Tx rings. */
11 
12 #include "aq_ring.h"
13 #include "aq_nic.h"
14 #include "aq_hw.h"
15 
16 #include <linux/netdevice.h>
17 #include <linux/etherdevice.h>
18 
19 static struct aq_ring_s *aq_ring_alloc(struct aq_ring_s *self,
20 				       struct aq_nic_s *aq_nic)
21 {
22 	int err = 0;
23 
24 	self->buff_ring =
25 		kcalloc(self->size, sizeof(struct aq_ring_buff_s), GFP_KERNEL);
26 
27 	if (!self->buff_ring) {
28 		err = -ENOMEM;
29 		goto err_exit;
30 	}
31 	self->dx_ring = dma_alloc_coherent(aq_nic_get_dev(aq_nic),
32 					   self->size * self->dx_size,
33 					   &self->dx_ring_pa, GFP_KERNEL);
34 	if (!self->dx_ring) {
35 		err = -ENOMEM;
36 		goto err_exit;
37 	}
38 
39 err_exit:
40 	if (err < 0) {
41 		aq_ring_free(self);
42 		self = NULL;
43 	}
44 	return self;
45 }
46 
47 struct aq_ring_s *aq_ring_tx_alloc(struct aq_ring_s *self,
48 				   struct aq_nic_s *aq_nic,
49 				   unsigned int idx,
50 				   struct aq_nic_cfg_s *aq_nic_cfg)
51 {
52 	int err = 0;
53 
54 	self->aq_nic = aq_nic;
55 	self->idx = idx;
56 	self->size = aq_nic_cfg->txds;
57 	self->dx_size = aq_nic_cfg->aq_hw_caps->txd_size;
58 
59 	self = aq_ring_alloc(self, aq_nic);
60 	if (!self) {
61 		err = -ENOMEM;
62 		goto err_exit;
63 	}
64 
65 err_exit:
66 	if (err < 0) {
67 		aq_ring_free(self);
68 		self = NULL;
69 	}
70 	return self;
71 }
72 
73 struct aq_ring_s *aq_ring_rx_alloc(struct aq_ring_s *self,
74 				   struct aq_nic_s *aq_nic,
75 				   unsigned int idx,
76 				   struct aq_nic_cfg_s *aq_nic_cfg)
77 {
78 	int err = 0;
79 
80 	self->aq_nic = aq_nic;
81 	self->idx = idx;
82 	self->size = aq_nic_cfg->rxds;
83 	self->dx_size = aq_nic_cfg->aq_hw_caps->rxd_size;
84 
85 	self = aq_ring_alloc(self, aq_nic);
86 	if (!self) {
87 		err = -ENOMEM;
88 		goto err_exit;
89 	}
90 
91 err_exit:
92 	if (err < 0) {
93 		aq_ring_free(self);
94 		self = NULL;
95 	}
96 	return self;
97 }
98 
99 int aq_ring_init(struct aq_ring_s *self)
100 {
101 	self->hw_head = 0;
102 	self->sw_head = 0;
103 	self->sw_tail = 0;
104 	return 0;
105 }
106 
107 static inline bool aq_ring_dx_in_range(unsigned int h, unsigned int i,
108 				       unsigned int t)
109 {
110 	return (h < t) ? ((h < i) && (i < t)) : ((h < i) || (i < t));
111 }
112 
113 void aq_ring_update_queue_state(struct aq_ring_s *ring)
114 {
115 	if (aq_ring_avail_dx(ring) <= AQ_CFG_SKB_FRAGS_MAX)
116 		aq_ring_queue_stop(ring);
117 	else if (aq_ring_avail_dx(ring) > AQ_CFG_RESTART_DESC_THRES)
118 		aq_ring_queue_wake(ring);
119 }
120 
121 void aq_ring_queue_wake(struct aq_ring_s *ring)
122 {
123 	struct net_device *ndev = aq_nic_get_ndev(ring->aq_nic);
124 
125 	if (__netif_subqueue_stopped(ndev, ring->idx)) {
126 		netif_wake_subqueue(ndev, ring->idx);
127 		ring->stats.tx.queue_restarts++;
128 	}
129 }
130 
131 void aq_ring_queue_stop(struct aq_ring_s *ring)
132 {
133 	struct net_device *ndev = aq_nic_get_ndev(ring->aq_nic);
134 
135 	if (!__netif_subqueue_stopped(ndev, ring->idx))
136 		netif_stop_subqueue(ndev, ring->idx);
137 }
138 
139 bool aq_ring_tx_clean(struct aq_ring_s *self)
140 {
141 	struct device *dev = aq_nic_get_dev(self->aq_nic);
142 	unsigned int budget = AQ_CFG_TX_CLEAN_BUDGET;
143 
144 	for (; self->sw_head != self->hw_head && budget--;
145 		self->sw_head = aq_ring_next_dx(self, self->sw_head)) {
146 		struct aq_ring_buff_s *buff = &self->buff_ring[self->sw_head];
147 
148 		if (likely(buff->is_mapped)) {
149 			if (unlikely(buff->is_sop)) {
150 				if (!buff->is_eop &&
151 				    buff->eop_index != 0xffffU &&
152 				    (!aq_ring_dx_in_range(self->sw_head,
153 						buff->eop_index,
154 						self->hw_head)))
155 					break;
156 
157 				dma_unmap_single(dev, buff->pa, buff->len,
158 						 DMA_TO_DEVICE);
159 			} else {
160 				dma_unmap_page(dev, buff->pa, buff->len,
161 					       DMA_TO_DEVICE);
162 			}
163 		}
164 
165 		if (unlikely(buff->is_eop))
166 			dev_kfree_skb_any(buff->skb);
167 
168 		buff->pa = 0U;
169 		buff->eop_index = 0xffffU;
170 	}
171 
172 	return !!budget;
173 }
174 
175 #define AQ_SKB_ALIGN SKB_DATA_ALIGN(sizeof(struct skb_shared_info))
176 int aq_ring_rx_clean(struct aq_ring_s *self,
177 		     struct napi_struct *napi,
178 		     int *work_done,
179 		     int budget)
180 {
181 	struct net_device *ndev = aq_nic_get_ndev(self->aq_nic);
182 	int err = 0;
183 	bool is_rsc_completed = true;
184 
185 	for (; (self->sw_head != self->hw_head) && budget;
186 		self->sw_head = aq_ring_next_dx(self, self->sw_head),
187 		--budget, ++(*work_done)) {
188 		struct aq_ring_buff_s *buff = &self->buff_ring[self->sw_head];
189 		struct sk_buff *skb = NULL;
190 		unsigned int next_ = 0U;
191 		unsigned int i = 0U;
192 		struct aq_ring_buff_s *buff_ = NULL;
193 
194 		if (buff->is_error) {
195 			__free_pages(buff->page, 0);
196 			continue;
197 		}
198 
199 		if (buff->is_cleaned)
200 			continue;
201 
202 		if (!buff->is_eop) {
203 			for (next_ = buff->next,
204 			     buff_ = &self->buff_ring[next_]; true;
205 			     next_ = buff_->next,
206 			     buff_ = &self->buff_ring[next_]) {
207 				is_rsc_completed =
208 					aq_ring_dx_in_range(self->sw_head,
209 							    next_,
210 							    self->hw_head);
211 
212 				if (unlikely(!is_rsc_completed)) {
213 					is_rsc_completed = false;
214 					break;
215 				}
216 
217 				if (buff_->is_eop)
218 					break;
219 			}
220 
221 			if (!is_rsc_completed) {
222 				err = 0;
223 				goto err_exit;
224 			}
225 		}
226 
227 		/* for single fragment packets use build_skb() */
228 		if (buff->is_eop &&
229 		    buff->len <= AQ_CFG_RX_FRAME_MAX - AQ_SKB_ALIGN) {
230 			skb = build_skb(page_address(buff->page),
231 					AQ_CFG_RX_FRAME_MAX);
232 			if (unlikely(!skb)) {
233 				err = -ENOMEM;
234 				goto err_exit;
235 			}
236 
237 			skb_put(skb, buff->len);
238 		} else {
239 			skb = netdev_alloc_skb(ndev, ETH_HLEN);
240 			if (unlikely(!skb)) {
241 				err = -ENOMEM;
242 				goto err_exit;
243 			}
244 			skb_put(skb, ETH_HLEN);
245 			memcpy(skb->data, page_address(buff->page), ETH_HLEN);
246 
247 			skb_add_rx_frag(skb, 0, buff->page, ETH_HLEN,
248 					buff->len - ETH_HLEN,
249 					SKB_TRUESIZE(buff->len - ETH_HLEN));
250 
251 			if (!buff->is_eop) {
252 				for (i = 1U, next_ = buff->next,
253 				     buff_ = &self->buff_ring[next_];
254 				     true; next_ = buff_->next,
255 				     buff_ = &self->buff_ring[next_], ++i) {
256 					skb_add_rx_frag(skb, i,
257 							buff_->page, 0,
258 							buff_->len,
259 							SKB_TRUESIZE(buff->len -
260 							ETH_HLEN));
261 					buff_->is_cleaned = 1;
262 
263 					if (buff_->is_eop)
264 						break;
265 				}
266 			}
267 		}
268 
269 		skb->protocol = eth_type_trans(skb, ndev);
270 		if (unlikely(buff->is_cso_err)) {
271 			++self->stats.rx.errors;
272 			skb->ip_summed = CHECKSUM_NONE;
273 		} else {
274 			if (buff->is_ip_cso) {
275 				__skb_incr_checksum_unnecessary(skb);
276 				if (buff->is_udp_cso || buff->is_tcp_cso)
277 					__skb_incr_checksum_unnecessary(skb);
278 			} else {
279 				skb->ip_summed = CHECKSUM_NONE;
280 			}
281 		}
282 
283 		skb_set_hash(skb, buff->rss_hash,
284 			     buff->is_hash_l4 ? PKT_HASH_TYPE_L4 :
285 			     PKT_HASH_TYPE_NONE);
286 
287 		skb_record_rx_queue(skb, self->idx);
288 
289 		++self->stats.rx.packets;
290 		self->stats.rx.bytes += skb->len;
291 
292 		napi_gro_receive(napi, skb);
293 	}
294 
295 err_exit:
296 	return err;
297 }
298 
299 int aq_ring_rx_fill(struct aq_ring_s *self)
300 {
301 	unsigned int pages_order = fls(AQ_CFG_RX_FRAME_MAX / PAGE_SIZE +
302 		(AQ_CFG_RX_FRAME_MAX % PAGE_SIZE ? 1 : 0)) - 1;
303 	struct aq_ring_buff_s *buff = NULL;
304 	int err = 0;
305 	int i = 0;
306 
307 	for (i = aq_ring_avail_dx(self); i--;
308 		self->sw_tail = aq_ring_next_dx(self, self->sw_tail)) {
309 		buff = &self->buff_ring[self->sw_tail];
310 
311 		buff->flags = 0U;
312 		buff->len = AQ_CFG_RX_FRAME_MAX;
313 
314 		buff->page = alloc_pages(GFP_ATOMIC | __GFP_COMP, pages_order);
315 		if (!buff->page) {
316 			err = -ENOMEM;
317 			goto err_exit;
318 		}
319 
320 		buff->pa = dma_map_page(aq_nic_get_dev(self->aq_nic),
321 					buff->page, 0,
322 					AQ_CFG_RX_FRAME_MAX, DMA_FROM_DEVICE);
323 
324 		if (dma_mapping_error(aq_nic_get_dev(self->aq_nic), buff->pa)) {
325 			err = -ENOMEM;
326 			goto err_exit;
327 		}
328 
329 		buff = NULL;
330 	}
331 
332 err_exit:
333 	if (err < 0) {
334 		if (buff && buff->page)
335 			__free_pages(buff->page, 0);
336 	}
337 
338 	return err;
339 }
340 
341 void aq_ring_rx_deinit(struct aq_ring_s *self)
342 {
343 	if (!self)
344 		goto err_exit;
345 
346 	for (; self->sw_head != self->sw_tail;
347 		self->sw_head = aq_ring_next_dx(self, self->sw_head)) {
348 		struct aq_ring_buff_s *buff = &self->buff_ring[self->sw_head];
349 
350 		dma_unmap_page(aq_nic_get_dev(self->aq_nic), buff->pa,
351 			       AQ_CFG_RX_FRAME_MAX, DMA_FROM_DEVICE);
352 
353 		__free_pages(buff->page, 0);
354 	}
355 
356 err_exit:;
357 }
358 
359 void aq_ring_free(struct aq_ring_s *self)
360 {
361 	if (!self)
362 		goto err_exit;
363 
364 	kfree(self->buff_ring);
365 
366 	if (self->dx_ring)
367 		dma_free_coherent(aq_nic_get_dev(self->aq_nic),
368 				  self->size * self->dx_size, self->dx_ring,
369 				  self->dx_ring_pa);
370 
371 err_exit:;
372 }
373