1 // SPDX-License-Identifier: GPL-2.0 or BSD-3-Clause
2 /*
3  * Copyright(c) 2017 - 2018 Intel Corporation.
4  */
5 
6 /*
7  * This file contains HFI1 support for VNIC SDMA functionality
8  */
9 
10 #include "sdma.h"
11 #include "vnic.h"
12 
13 #define HFI1_VNIC_SDMA_Q_ACTIVE   BIT(0)
14 #define HFI1_VNIC_SDMA_Q_DEFERRED BIT(1)
15 
16 #define HFI1_VNIC_TXREQ_NAME_LEN   32
17 #define HFI1_VNIC_SDMA_DESC_WTRMRK 64
18 
19 /*
20  * struct vnic_txreq - VNIC transmit descriptor
21  * @txreq: sdma transmit request
22  * @sdma: vnic sdma pointer
23  * @skb: skb to send
24  * @pad: pad buffer
25  * @plen: pad length
26  * @pbc_val: pbc value
27  */
28 struct vnic_txreq {
29 	struct sdma_txreq       txreq;
30 	struct hfi1_vnic_sdma   *sdma;
31 
32 	struct sk_buff         *skb;
33 	unsigned char           pad[HFI1_VNIC_MAX_PAD];
34 	u16                     plen;
35 	__le64                  pbc_val;
36 };
37 
38 static void vnic_sdma_complete(struct sdma_txreq *txreq,
39 			       int status)
40 {
41 	struct vnic_txreq *tx = container_of(txreq, struct vnic_txreq, txreq);
42 	struct hfi1_vnic_sdma *vnic_sdma = tx->sdma;
43 
44 	sdma_txclean(vnic_sdma->dd, txreq);
45 	dev_kfree_skb_any(tx->skb);
46 	kmem_cache_free(vnic_sdma->dd->vnic.txreq_cache, tx);
47 }
48 
49 static noinline int build_vnic_ulp_payload(struct sdma_engine *sde,
50 					   struct vnic_txreq *tx)
51 {
52 	int i, ret = 0;
53 
54 	ret = sdma_txadd_kvaddr(
55 		sde->dd,
56 		&tx->txreq,
57 		tx->skb->data,
58 		skb_headlen(tx->skb));
59 	if (unlikely(ret))
60 		goto bail_txadd;
61 
62 	for (i = 0; i < skb_shinfo(tx->skb)->nr_frags; i++) {
63 		skb_frag_t *frag = &skb_shinfo(tx->skb)->frags[i];
64 
65 		/* combine physically continuous fragments later? */
66 		ret = sdma_txadd_page(sde->dd,
67 				      NULL,
68 				      &tx->txreq,
69 				      skb_frag_page(frag),
70 				      skb_frag_off(frag),
71 				      skb_frag_size(frag));
72 		if (unlikely(ret))
73 			goto bail_txadd;
74 	}
75 
76 	if (tx->plen)
77 		ret = sdma_txadd_kvaddr(sde->dd, &tx->txreq,
78 					tx->pad + HFI1_VNIC_MAX_PAD - tx->plen,
79 					tx->plen);
80 
81 bail_txadd:
82 	return ret;
83 }
84 
85 static int build_vnic_tx_desc(struct sdma_engine *sde,
86 			      struct vnic_txreq *tx,
87 			      u64 pbc)
88 {
89 	int ret = 0;
90 	u16 hdrbytes = 2 << 2;  /* PBC */
91 
92 	ret = sdma_txinit_ahg(
93 		&tx->txreq,
94 		0,
95 		hdrbytes + tx->skb->len + tx->plen,
96 		0,
97 		0,
98 		NULL,
99 		0,
100 		vnic_sdma_complete);
101 	if (unlikely(ret))
102 		goto bail_txadd;
103 
104 	/* add pbc */
105 	tx->pbc_val = cpu_to_le64(pbc);
106 	ret = sdma_txadd_kvaddr(
107 		sde->dd,
108 		&tx->txreq,
109 		&tx->pbc_val,
110 		hdrbytes);
111 	if (unlikely(ret))
112 		goto bail_txadd;
113 
114 	/* add the ulp payload */
115 	ret = build_vnic_ulp_payload(sde, tx);
116 bail_txadd:
117 	return ret;
118 }
119 
120 /* setup the last plen bypes of pad */
121 static inline void hfi1_vnic_update_pad(unsigned char *pad, u8 plen)
122 {
123 	pad[HFI1_VNIC_MAX_PAD - 1] = plen - OPA_VNIC_ICRC_TAIL_LEN;
124 }
125 
126 int hfi1_vnic_send_dma(struct hfi1_devdata *dd, u8 q_idx,
127 		       struct hfi1_vnic_vport_info *vinfo,
128 		       struct sk_buff *skb, u64 pbc, u8 plen)
129 {
130 	struct hfi1_vnic_sdma *vnic_sdma = &vinfo->sdma[q_idx];
131 	struct sdma_engine *sde = vnic_sdma->sde;
132 	struct vnic_txreq *tx;
133 	int ret = -ECOMM;
134 
135 	if (unlikely(READ_ONCE(vnic_sdma->state) != HFI1_VNIC_SDMA_Q_ACTIVE))
136 		goto tx_err;
137 
138 	if (unlikely(!sde || !sdma_running(sde)))
139 		goto tx_err;
140 
141 	tx = kmem_cache_alloc(dd->vnic.txreq_cache, GFP_ATOMIC);
142 	if (unlikely(!tx)) {
143 		ret = -ENOMEM;
144 		goto tx_err;
145 	}
146 
147 	tx->sdma = vnic_sdma;
148 	tx->skb = skb;
149 	hfi1_vnic_update_pad(tx->pad, plen);
150 	tx->plen = plen;
151 	ret = build_vnic_tx_desc(sde, tx, pbc);
152 	if (unlikely(ret))
153 		goto free_desc;
154 
155 	ret = sdma_send_txreq(sde, iowait_get_ib_work(&vnic_sdma->wait),
156 			      &tx->txreq, vnic_sdma->pkts_sent);
157 	/* When -ECOMM, sdma callback will be called with ABORT status */
158 	if (unlikely(ret && unlikely(ret != -ECOMM)))
159 		goto free_desc;
160 
161 	if (!ret) {
162 		vnic_sdma->pkts_sent = true;
163 		iowait_starve_clear(vnic_sdma->pkts_sent, &vnic_sdma->wait);
164 	}
165 	return ret;
166 
167 free_desc:
168 	sdma_txclean(dd, &tx->txreq);
169 	kmem_cache_free(dd->vnic.txreq_cache, tx);
170 tx_err:
171 	if (ret != -EBUSY)
172 		dev_kfree_skb_any(skb);
173 	else
174 		vnic_sdma->pkts_sent = false;
175 	return ret;
176 }
177 
178 /*
179  * hfi1_vnic_sdma_sleep - vnic sdma sleep function
180  *
181  * This function gets called from sdma_send_txreq() when there are not enough
182  * sdma descriptors available to send the packet. It adds Tx queue's wait
183  * structure to sdma engine's dmawait list to be woken up when descriptors
184  * become available.
185  */
186 static int hfi1_vnic_sdma_sleep(struct sdma_engine *sde,
187 				struct iowait_work *wait,
188 				struct sdma_txreq *txreq,
189 				uint seq,
190 				bool pkts_sent)
191 {
192 	struct hfi1_vnic_sdma *vnic_sdma =
193 		container_of(wait->iow, struct hfi1_vnic_sdma, wait);
194 
195 	write_seqlock(&sde->waitlock);
196 	if (sdma_progress(sde, seq, txreq)) {
197 		write_sequnlock(&sde->waitlock);
198 		return -EAGAIN;
199 	}
200 
201 	vnic_sdma->state = HFI1_VNIC_SDMA_Q_DEFERRED;
202 	if (list_empty(&vnic_sdma->wait.list)) {
203 		iowait_get_priority(wait->iow);
204 		iowait_queue(pkts_sent, wait->iow, &sde->dmawait);
205 	}
206 	write_sequnlock(&sde->waitlock);
207 	return -EBUSY;
208 }
209 
210 /*
211  * hfi1_vnic_sdma_wakeup - vnic sdma wakeup function
212  *
213  * This function gets called when SDMA descriptors becomes available and Tx
214  * queue's wait structure was previously added to sdma engine's dmawait list.
215  * It notifies the upper driver about Tx queue wakeup.
216  */
217 static void hfi1_vnic_sdma_wakeup(struct iowait *wait, int reason)
218 {
219 	struct hfi1_vnic_sdma *vnic_sdma =
220 		container_of(wait, struct hfi1_vnic_sdma, wait);
221 	struct hfi1_vnic_vport_info *vinfo = vnic_sdma->vinfo;
222 
223 	vnic_sdma->state = HFI1_VNIC_SDMA_Q_ACTIVE;
224 	if (__netif_subqueue_stopped(vinfo->netdev, vnic_sdma->q_idx))
225 		netif_wake_subqueue(vinfo->netdev, vnic_sdma->q_idx);
226 };
227 
228 inline bool hfi1_vnic_sdma_write_avail(struct hfi1_vnic_vport_info *vinfo,
229 				       u8 q_idx)
230 {
231 	struct hfi1_vnic_sdma *vnic_sdma = &vinfo->sdma[q_idx];
232 
233 	return (READ_ONCE(vnic_sdma->state) == HFI1_VNIC_SDMA_Q_ACTIVE);
234 }
235 
236 void hfi1_vnic_sdma_init(struct hfi1_vnic_vport_info *vinfo)
237 {
238 	int i;
239 
240 	for (i = 0; i < vinfo->num_tx_q; i++) {
241 		struct hfi1_vnic_sdma *vnic_sdma = &vinfo->sdma[i];
242 
243 		iowait_init(&vnic_sdma->wait, 0, NULL, NULL,
244 			    hfi1_vnic_sdma_sleep,
245 			    hfi1_vnic_sdma_wakeup, NULL, NULL);
246 		vnic_sdma->sde = &vinfo->dd->per_sdma[i];
247 		vnic_sdma->dd = vinfo->dd;
248 		vnic_sdma->vinfo = vinfo;
249 		vnic_sdma->q_idx = i;
250 		vnic_sdma->state = HFI1_VNIC_SDMA_Q_ACTIVE;
251 
252 		/* Add a free descriptor watermark for wakeups */
253 		if (vnic_sdma->sde->descq_cnt > HFI1_VNIC_SDMA_DESC_WTRMRK) {
254 			struct iowait_work *work;
255 
256 			INIT_LIST_HEAD(&vnic_sdma->stx.list);
257 			vnic_sdma->stx.num_desc = HFI1_VNIC_SDMA_DESC_WTRMRK;
258 			work = iowait_get_ib_work(&vnic_sdma->wait);
259 			list_add_tail(&vnic_sdma->stx.list, &work->tx_head);
260 		}
261 	}
262 }
263 
264 int hfi1_vnic_txreq_init(struct hfi1_devdata *dd)
265 {
266 	char buf[HFI1_VNIC_TXREQ_NAME_LEN];
267 
268 	snprintf(buf, sizeof(buf), "hfi1_%u_vnic_txreq_cache", dd->unit);
269 	dd->vnic.txreq_cache = kmem_cache_create(buf,
270 						 sizeof(struct vnic_txreq),
271 						 0, SLAB_HWCACHE_ALIGN,
272 						 NULL);
273 	if (!dd->vnic.txreq_cache)
274 		return -ENOMEM;
275 	return 0;
276 }
277 
278 void hfi1_vnic_txreq_deinit(struct hfi1_devdata *dd)
279 {
280 	kmem_cache_destroy(dd->vnic.txreq_cache);
281 	dd->vnic.txreq_cache = NULL;
282 }
283