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 */
28struct 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
38static 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
49static 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				      NULL, NULL, NULL);
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
81bail_txadd:
82	return ret;
83}
84
85static 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);
116bail_txadd:
117	return ret;
118}
119
120/* setup the last plen bypes of pad */
121static 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
126int 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
167free_desc:
168	sdma_txclean(dd, &tx->txreq);
169	kmem_cache_free(dd->vnic.txreq_cache, tx);
170tx_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 */
186static 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 */
217static 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
228inline 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
236void 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
264int 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
278void 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