1 /*
2  * Copyright(c) 2017 Intel Corporation.
3  *
4  * This file is provided under a dual BSD/GPLv2 license.  When using or
5  * redistributing this file, you may do so under either license.
6  *
7  * GPL LICENSE SUMMARY
8  *
9  * This program is free software; you can redistribute it and/or modify
10  * it under the terms of version 2 of the GNU General Public License as
11  * published by the Free Software Foundation.
12  *
13  * This program is distributed in the hope that it will be useful, but
14  * WITHOUT ANY WARRANTY; without even the implied warranty of
15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
16  * General Public License for more details.
17  *
18  * BSD LICENSE
19  *
20  * Redistribution and use in source and binary forms, with or without
21  * modification, are permitted provided that the following conditions
22  * are met:
23  *
24  *  - Redistributions of source code must retain the above copyright
25  *    notice, this list of conditions and the following disclaimer.
26  *  - Redistributions in binary form must reproduce the above copyright
27  *    notice, this list of conditions and the following disclaimer in
28  *    the documentation and/or other materials provided with the
29  *    distribution.
30  *  - Neither the name of Intel Corporation nor the names of its
31  *    contributors may be used to endorse or promote products derived
32  *    from this software without specific prior written permission.
33  *
34  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
35  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
36  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
37  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
38  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
39  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
40  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
41  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
42  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
43  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
44  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
45  *
46  */
47 
48 /*
49  * This file contains HFI1 support for VNIC SDMA functionality
50  */
51 
52 #include "sdma.h"
53 #include "vnic.h"
54 
55 #define HFI1_VNIC_SDMA_Q_ACTIVE   BIT(0)
56 #define HFI1_VNIC_SDMA_Q_DEFERRED BIT(1)
57 
58 #define HFI1_VNIC_TXREQ_NAME_LEN   32
59 #define HFI1_VNIC_SDMA_DESC_WTRMRK 64
60 #define HFI1_VNIC_SDMA_RETRY_COUNT 1
61 
62 /*
63  * struct vnic_txreq - VNIC transmit descriptor
64  * @txreq: sdma transmit request
65  * @sdma: vnic sdma pointer
66  * @skb: skb to send
67  * @pad: pad buffer
68  * @plen: pad length
69  * @pbc_val: pbc value
70  * @retry_count: tx retry count
71  */
72 struct vnic_txreq {
73 	struct sdma_txreq       txreq;
74 	struct hfi1_vnic_sdma   *sdma;
75 
76 	struct sk_buff         *skb;
77 	unsigned char           pad[HFI1_VNIC_MAX_PAD];
78 	u16                     plen;
79 	__le64                  pbc_val;
80 
81 	u32                     retry_count;
82 };
83 
84 static void vnic_sdma_complete(struct sdma_txreq *txreq,
85 			       int status)
86 {
87 	struct vnic_txreq *tx = container_of(txreq, struct vnic_txreq, txreq);
88 	struct hfi1_vnic_sdma *vnic_sdma = tx->sdma;
89 
90 	sdma_txclean(vnic_sdma->dd, txreq);
91 	dev_kfree_skb_any(tx->skb);
92 	kmem_cache_free(vnic_sdma->dd->vnic.txreq_cache, tx);
93 }
94 
95 static noinline int build_vnic_ulp_payload(struct sdma_engine *sde,
96 					   struct vnic_txreq *tx)
97 {
98 	int i, ret = 0;
99 
100 	ret = sdma_txadd_kvaddr(
101 		sde->dd,
102 		&tx->txreq,
103 		tx->skb->data,
104 		skb_headlen(tx->skb));
105 	if (unlikely(ret))
106 		goto bail_txadd;
107 
108 	for (i = 0; i < skb_shinfo(tx->skb)->nr_frags; i++) {
109 		struct skb_frag_struct *frag = &skb_shinfo(tx->skb)->frags[i];
110 
111 		/* combine physically continuous fragments later? */
112 		ret = sdma_txadd_page(sde->dd,
113 				      &tx->txreq,
114 				      skb_frag_page(frag),
115 				      frag->page_offset,
116 				      skb_frag_size(frag));
117 		if (unlikely(ret))
118 			goto bail_txadd;
119 	}
120 
121 	if (tx->plen)
122 		ret = sdma_txadd_kvaddr(sde->dd, &tx->txreq,
123 					tx->pad + HFI1_VNIC_MAX_PAD - tx->plen,
124 					tx->plen);
125 
126 bail_txadd:
127 	return ret;
128 }
129 
130 static int build_vnic_tx_desc(struct sdma_engine *sde,
131 			      struct vnic_txreq *tx,
132 			      u64 pbc)
133 {
134 	int ret = 0;
135 	u16 hdrbytes = 2 << 2;  /* PBC */
136 
137 	ret = sdma_txinit_ahg(
138 		&tx->txreq,
139 		0,
140 		hdrbytes + tx->skb->len + tx->plen,
141 		0,
142 		0,
143 		NULL,
144 		0,
145 		vnic_sdma_complete);
146 	if (unlikely(ret))
147 		goto bail_txadd;
148 
149 	/* add pbc */
150 	tx->pbc_val = cpu_to_le64(pbc);
151 	ret = sdma_txadd_kvaddr(
152 		sde->dd,
153 		&tx->txreq,
154 		&tx->pbc_val,
155 		hdrbytes);
156 	if (unlikely(ret))
157 		goto bail_txadd;
158 
159 	/* add the ulp payload */
160 	ret = build_vnic_ulp_payload(sde, tx);
161 bail_txadd:
162 	return ret;
163 }
164 
165 /* setup the last plen bypes of pad */
166 static inline void hfi1_vnic_update_pad(unsigned char *pad, u8 plen)
167 {
168 	pad[HFI1_VNIC_MAX_PAD - 1] = plen - OPA_VNIC_ICRC_TAIL_LEN;
169 }
170 
171 int hfi1_vnic_send_dma(struct hfi1_devdata *dd, u8 q_idx,
172 		       struct hfi1_vnic_vport_info *vinfo,
173 		       struct sk_buff *skb, u64 pbc, u8 plen)
174 {
175 	struct hfi1_vnic_sdma *vnic_sdma = &vinfo->sdma[q_idx];
176 	struct sdma_engine *sde = vnic_sdma->sde;
177 	struct vnic_txreq *tx;
178 	int ret = -ECOMM;
179 
180 	if (unlikely(READ_ONCE(vnic_sdma->state) != HFI1_VNIC_SDMA_Q_ACTIVE))
181 		goto tx_err;
182 
183 	if (unlikely(!sde || !sdma_running(sde)))
184 		goto tx_err;
185 
186 	tx = kmem_cache_alloc(dd->vnic.txreq_cache, GFP_ATOMIC);
187 	if (unlikely(!tx)) {
188 		ret = -ENOMEM;
189 		goto tx_err;
190 	}
191 
192 	tx->sdma = vnic_sdma;
193 	tx->skb = skb;
194 	hfi1_vnic_update_pad(tx->pad, plen);
195 	tx->plen = plen;
196 	ret = build_vnic_tx_desc(sde, tx, pbc);
197 	if (unlikely(ret))
198 		goto free_desc;
199 	tx->retry_count = 0;
200 
201 	ret = sdma_send_txreq(sde, &vnic_sdma->wait, &tx->txreq,
202 			      vnic_sdma->pkts_sent);
203 	/* When -ECOMM, sdma callback will be called with ABORT status */
204 	if (unlikely(ret && unlikely(ret != -ECOMM)))
205 		goto free_desc;
206 
207 	if (!ret) {
208 		vnic_sdma->pkts_sent = true;
209 		iowait_starve_clear(vnic_sdma->pkts_sent, &vnic_sdma->wait);
210 	}
211 	return ret;
212 
213 free_desc:
214 	sdma_txclean(dd, &tx->txreq);
215 	kmem_cache_free(dd->vnic.txreq_cache, tx);
216 tx_err:
217 	if (ret != -EBUSY)
218 		dev_kfree_skb_any(skb);
219 	else
220 		vnic_sdma->pkts_sent = false;
221 	return ret;
222 }
223 
224 /*
225  * hfi1_vnic_sdma_sleep - vnic sdma sleep function
226  *
227  * This function gets called from sdma_send_txreq() when there are not enough
228  * sdma descriptors available to send the packet. It adds Tx queue's wait
229  * structure to sdma engine's dmawait list to be woken up when descriptors
230  * become available.
231  */
232 static int hfi1_vnic_sdma_sleep(struct sdma_engine *sde,
233 				struct iowait *wait,
234 				struct sdma_txreq *txreq,
235 				uint seq,
236 				bool pkts_sent)
237 {
238 	struct hfi1_vnic_sdma *vnic_sdma =
239 		container_of(wait, struct hfi1_vnic_sdma, wait);
240 	struct hfi1_ibdev *dev = &vnic_sdma->dd->verbs_dev;
241 	struct vnic_txreq *tx = container_of(txreq, struct vnic_txreq, txreq);
242 
243 	if (sdma_progress(sde, seq, txreq))
244 		if (tx->retry_count++ < HFI1_VNIC_SDMA_RETRY_COUNT)
245 			return -EAGAIN;
246 
247 	vnic_sdma->state = HFI1_VNIC_SDMA_Q_DEFERRED;
248 	write_seqlock(&dev->iowait_lock);
249 	if (list_empty(&vnic_sdma->wait.list))
250 		iowait_queue(pkts_sent, wait, &sde->dmawait);
251 	write_sequnlock(&dev->iowait_lock);
252 	return -EBUSY;
253 }
254 
255 /*
256  * hfi1_vnic_sdma_wakeup - vnic sdma wakeup function
257  *
258  * This function gets called when SDMA descriptors becomes available and Tx
259  * queue's wait structure was previously added to sdma engine's dmawait list.
260  * It notifies the upper driver about Tx queue wakeup.
261  */
262 static void hfi1_vnic_sdma_wakeup(struct iowait *wait, int reason)
263 {
264 	struct hfi1_vnic_sdma *vnic_sdma =
265 		container_of(wait, struct hfi1_vnic_sdma, wait);
266 	struct hfi1_vnic_vport_info *vinfo = vnic_sdma->vinfo;
267 
268 	vnic_sdma->state = HFI1_VNIC_SDMA_Q_ACTIVE;
269 	if (__netif_subqueue_stopped(vinfo->netdev, vnic_sdma->q_idx))
270 		netif_wake_subqueue(vinfo->netdev, vnic_sdma->q_idx);
271 };
272 
273 inline bool hfi1_vnic_sdma_write_avail(struct hfi1_vnic_vport_info *vinfo,
274 				       u8 q_idx)
275 {
276 	struct hfi1_vnic_sdma *vnic_sdma = &vinfo->sdma[q_idx];
277 
278 	return (READ_ONCE(vnic_sdma->state) == HFI1_VNIC_SDMA_Q_ACTIVE);
279 }
280 
281 void hfi1_vnic_sdma_init(struct hfi1_vnic_vport_info *vinfo)
282 {
283 	int i;
284 
285 	for (i = 0; i < vinfo->num_tx_q; i++) {
286 		struct hfi1_vnic_sdma *vnic_sdma = &vinfo->sdma[i];
287 
288 		iowait_init(&vnic_sdma->wait, 0, NULL, hfi1_vnic_sdma_sleep,
289 			    hfi1_vnic_sdma_wakeup, NULL);
290 		vnic_sdma->sde = &vinfo->dd->per_sdma[i];
291 		vnic_sdma->dd = vinfo->dd;
292 		vnic_sdma->vinfo = vinfo;
293 		vnic_sdma->q_idx = i;
294 		vnic_sdma->state = HFI1_VNIC_SDMA_Q_ACTIVE;
295 
296 		/* Add a free descriptor watermark for wakeups */
297 		if (vnic_sdma->sde->descq_cnt > HFI1_VNIC_SDMA_DESC_WTRMRK) {
298 			INIT_LIST_HEAD(&vnic_sdma->stx.list);
299 			vnic_sdma->stx.num_desc = HFI1_VNIC_SDMA_DESC_WTRMRK;
300 			list_add_tail(&vnic_sdma->stx.list,
301 				      &vnic_sdma->wait.tx_head);
302 		}
303 	}
304 }
305 
306 int hfi1_vnic_txreq_init(struct hfi1_devdata *dd)
307 {
308 	char buf[HFI1_VNIC_TXREQ_NAME_LEN];
309 
310 	snprintf(buf, sizeof(buf), "hfi1_%u_vnic_txreq_cache", dd->unit);
311 	dd->vnic.txreq_cache = kmem_cache_create(buf,
312 						 sizeof(struct vnic_txreq),
313 						 0, SLAB_HWCACHE_ALIGN,
314 						 NULL);
315 	if (!dd->vnic.txreq_cache)
316 		return -ENOMEM;
317 	return 0;
318 }
319 
320 void hfi1_vnic_txreq_deinit(struct hfi1_devdata *dd)
321 {
322 	kmem_cache_destroy(dd->vnic.txreq_cache);
323 	dd->vnic.txreq_cache = NULL;
324 }
325