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