1 /*
2  * Copyright(c) 2017 - 2018 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 
61 /*
62  * struct vnic_txreq - VNIC transmit descriptor
63  * @txreq: sdma transmit request
64  * @sdma: vnic sdma pointer
65  * @skb: skb to send
66  * @pad: pad buffer
67  * @plen: pad length
68  * @pbc_val: pbc value
69  */
70 struct vnic_txreq {
71 	struct sdma_txreq       txreq;
72 	struct hfi1_vnic_sdma   *sdma;
73 
74 	struct sk_buff         *skb;
75 	unsigned char           pad[HFI1_VNIC_MAX_PAD];
76 	u16                     plen;
77 	__le64                  pbc_val;
78 };
79 
80 static void vnic_sdma_complete(struct sdma_txreq *txreq,
81 			       int status)
82 {
83 	struct vnic_txreq *tx = container_of(txreq, struct vnic_txreq, txreq);
84 	struct hfi1_vnic_sdma *vnic_sdma = tx->sdma;
85 
86 	sdma_txclean(vnic_sdma->dd, txreq);
87 	dev_kfree_skb_any(tx->skb);
88 	kmem_cache_free(vnic_sdma->dd->vnic.txreq_cache, tx);
89 }
90 
91 static noinline int build_vnic_ulp_payload(struct sdma_engine *sde,
92 					   struct vnic_txreq *tx)
93 {
94 	int i, ret = 0;
95 
96 	ret = sdma_txadd_kvaddr(
97 		sde->dd,
98 		&tx->txreq,
99 		tx->skb->data,
100 		skb_headlen(tx->skb));
101 	if (unlikely(ret))
102 		goto bail_txadd;
103 
104 	for (i = 0; i < skb_shinfo(tx->skb)->nr_frags; i++) {
105 		struct skb_frag_struct *frag = &skb_shinfo(tx->skb)->frags[i];
106 
107 		/* combine physically continuous fragments later? */
108 		ret = sdma_txadd_page(sde->dd,
109 				      &tx->txreq,
110 				      skb_frag_page(frag),
111 				      frag->page_offset,
112 				      skb_frag_size(frag));
113 		if (unlikely(ret))
114 			goto bail_txadd;
115 	}
116 
117 	if (tx->plen)
118 		ret = sdma_txadd_kvaddr(sde->dd, &tx->txreq,
119 					tx->pad + HFI1_VNIC_MAX_PAD - tx->plen,
120 					tx->plen);
121 
122 bail_txadd:
123 	return ret;
124 }
125 
126 static int build_vnic_tx_desc(struct sdma_engine *sde,
127 			      struct vnic_txreq *tx,
128 			      u64 pbc)
129 {
130 	int ret = 0;
131 	u16 hdrbytes = 2 << 2;  /* PBC */
132 
133 	ret = sdma_txinit_ahg(
134 		&tx->txreq,
135 		0,
136 		hdrbytes + tx->skb->len + tx->plen,
137 		0,
138 		0,
139 		NULL,
140 		0,
141 		vnic_sdma_complete);
142 	if (unlikely(ret))
143 		goto bail_txadd;
144 
145 	/* add pbc */
146 	tx->pbc_val = cpu_to_le64(pbc);
147 	ret = sdma_txadd_kvaddr(
148 		sde->dd,
149 		&tx->txreq,
150 		&tx->pbc_val,
151 		hdrbytes);
152 	if (unlikely(ret))
153 		goto bail_txadd;
154 
155 	/* add the ulp payload */
156 	ret = build_vnic_ulp_payload(sde, tx);
157 bail_txadd:
158 	return ret;
159 }
160 
161 /* setup the last plen bypes of pad */
162 static inline void hfi1_vnic_update_pad(unsigned char *pad, u8 plen)
163 {
164 	pad[HFI1_VNIC_MAX_PAD - 1] = plen - OPA_VNIC_ICRC_TAIL_LEN;
165 }
166 
167 int hfi1_vnic_send_dma(struct hfi1_devdata *dd, u8 q_idx,
168 		       struct hfi1_vnic_vport_info *vinfo,
169 		       struct sk_buff *skb, u64 pbc, u8 plen)
170 {
171 	struct hfi1_vnic_sdma *vnic_sdma = &vinfo->sdma[q_idx];
172 	struct sdma_engine *sde = vnic_sdma->sde;
173 	struct vnic_txreq *tx;
174 	int ret = -ECOMM;
175 
176 	if (unlikely(READ_ONCE(vnic_sdma->state) != HFI1_VNIC_SDMA_Q_ACTIVE))
177 		goto tx_err;
178 
179 	if (unlikely(!sde || !sdma_running(sde)))
180 		goto tx_err;
181 
182 	tx = kmem_cache_alloc(dd->vnic.txreq_cache, GFP_ATOMIC);
183 	if (unlikely(!tx)) {
184 		ret = -ENOMEM;
185 		goto tx_err;
186 	}
187 
188 	tx->sdma = vnic_sdma;
189 	tx->skb = skb;
190 	hfi1_vnic_update_pad(tx->pad, plen);
191 	tx->plen = plen;
192 	ret = build_vnic_tx_desc(sde, tx, pbc);
193 	if (unlikely(ret))
194 		goto free_desc;
195 
196 	ret = sdma_send_txreq(sde, iowait_get_ib_work(&vnic_sdma->wait),
197 			      &tx->txreq, vnic_sdma->pkts_sent);
198 	/* When -ECOMM, sdma callback will be called with ABORT status */
199 	if (unlikely(ret && unlikely(ret != -ECOMM)))
200 		goto free_desc;
201 
202 	if (!ret) {
203 		vnic_sdma->pkts_sent = true;
204 		iowait_starve_clear(vnic_sdma->pkts_sent, &vnic_sdma->wait);
205 	}
206 	return ret;
207 
208 free_desc:
209 	sdma_txclean(dd, &tx->txreq);
210 	kmem_cache_free(dd->vnic.txreq_cache, tx);
211 tx_err:
212 	if (ret != -EBUSY)
213 		dev_kfree_skb_any(skb);
214 	else
215 		vnic_sdma->pkts_sent = false;
216 	return ret;
217 }
218 
219 /*
220  * hfi1_vnic_sdma_sleep - vnic sdma sleep function
221  *
222  * This function gets called from sdma_send_txreq() when there are not enough
223  * sdma descriptors available to send the packet. It adds Tx queue's wait
224  * structure to sdma engine's dmawait list to be woken up when descriptors
225  * become available.
226  */
227 static int hfi1_vnic_sdma_sleep(struct sdma_engine *sde,
228 				struct iowait_work *wait,
229 				struct sdma_txreq *txreq,
230 				uint seq,
231 				bool pkts_sent)
232 {
233 	struct hfi1_vnic_sdma *vnic_sdma =
234 		container_of(wait->iow, struct hfi1_vnic_sdma, wait);
235 
236 	write_seqlock(&sde->waitlock);
237 	if (sdma_progress(sde, seq, txreq)) {
238 		write_sequnlock(&sde->waitlock);
239 		return -EAGAIN;
240 	}
241 
242 	vnic_sdma->state = HFI1_VNIC_SDMA_Q_DEFERRED;
243 	if (list_empty(&vnic_sdma->wait.list)) {
244 		iowait_get_priority(wait->iow);
245 		iowait_queue(pkts_sent, wait->iow, &sde->dmawait);
246 	}
247 	write_sequnlock(&sde->waitlock);
248 	return -EBUSY;
249 }
250 
251 /*
252  * hfi1_vnic_sdma_wakeup - vnic sdma wakeup function
253  *
254  * This function gets called when SDMA descriptors becomes available and Tx
255  * queue's wait structure was previously added to sdma engine's dmawait list.
256  * It notifies the upper driver about Tx queue wakeup.
257  */
258 static void hfi1_vnic_sdma_wakeup(struct iowait *wait, int reason)
259 {
260 	struct hfi1_vnic_sdma *vnic_sdma =
261 		container_of(wait, struct hfi1_vnic_sdma, wait);
262 	struct hfi1_vnic_vport_info *vinfo = vnic_sdma->vinfo;
263 
264 	vnic_sdma->state = HFI1_VNIC_SDMA_Q_ACTIVE;
265 	if (__netif_subqueue_stopped(vinfo->netdev, vnic_sdma->q_idx))
266 		netif_wake_subqueue(vinfo->netdev, vnic_sdma->q_idx);
267 };
268 
269 inline bool hfi1_vnic_sdma_write_avail(struct hfi1_vnic_vport_info *vinfo,
270 				       u8 q_idx)
271 {
272 	struct hfi1_vnic_sdma *vnic_sdma = &vinfo->sdma[q_idx];
273 
274 	return (READ_ONCE(vnic_sdma->state) == HFI1_VNIC_SDMA_Q_ACTIVE);
275 }
276 
277 void hfi1_vnic_sdma_init(struct hfi1_vnic_vport_info *vinfo)
278 {
279 	int i;
280 
281 	for (i = 0; i < vinfo->num_tx_q; i++) {
282 		struct hfi1_vnic_sdma *vnic_sdma = &vinfo->sdma[i];
283 
284 		iowait_init(&vnic_sdma->wait, 0, NULL, NULL,
285 			    hfi1_vnic_sdma_sleep,
286 			    hfi1_vnic_sdma_wakeup, NULL, NULL);
287 		vnic_sdma->sde = &vinfo->dd->per_sdma[i];
288 		vnic_sdma->dd = vinfo->dd;
289 		vnic_sdma->vinfo = vinfo;
290 		vnic_sdma->q_idx = i;
291 		vnic_sdma->state = HFI1_VNIC_SDMA_Q_ACTIVE;
292 
293 		/* Add a free descriptor watermark for wakeups */
294 		if (vnic_sdma->sde->descq_cnt > HFI1_VNIC_SDMA_DESC_WTRMRK) {
295 			struct iowait_work *work;
296 
297 			INIT_LIST_HEAD(&vnic_sdma->stx.list);
298 			vnic_sdma->stx.num_desc = HFI1_VNIC_SDMA_DESC_WTRMRK;
299 			work = iowait_get_ib_work(&vnic_sdma->wait);
300 			list_add_tail(&vnic_sdma->stx.list, &work->tx_head);
301 		}
302 	}
303 }
304 
305 int hfi1_vnic_txreq_init(struct hfi1_devdata *dd)
306 {
307 	char buf[HFI1_VNIC_TXREQ_NAME_LEN];
308 
309 	snprintf(buf, sizeof(buf), "hfi1_%u_vnic_txreq_cache", dd->unit);
310 	dd->vnic.txreq_cache = kmem_cache_create(buf,
311 						 sizeof(struct vnic_txreq),
312 						 0, SLAB_HWCACHE_ALIGN,
313 						 NULL);
314 	if (!dd->vnic.txreq_cache)
315 		return -ENOMEM;
316 	return 0;
317 }
318 
319 void hfi1_vnic_txreq_deinit(struct hfi1_devdata *dd)
320 {
321 	kmem_cache_destroy(dd->vnic.txreq_cache);
322 	dd->vnic.txreq_cache = NULL;
323 }
324