1/*-
2 * SPDX-License-Identifier: BSD-2-Clause OR GPL-2.0
3 *
4 * Copyright (c) 2017 Mellanox Technologies Ltd.  All rights reserved.
5 *
6 * This software is available to you under a choice of one of two
7 * licenses.  You may choose to be licensed under the terms of the GNU
8 * General Public License (GPL) Version 2, available from the file
9 * COPYING in the main directory of this source tree, or the
10 * OpenIB.org BSD license below:
11 *
12 *     Redistribution and use in source and binary forms, with or
13 *     without modification, are permitted provided that the following
14 *     conditions are met:
15 *
16 *      - Redistributions of source code must retain the above
17 *        copyright notice, this list of conditions and the following
18 *        disclaimer.
19 *
20 *      - Redistributions in binary form must reproduce the above
21 *        copyright notice, this list of conditions and the following
22 *        disclaimer in the documentation and/or other materials
23 *        provided with the distribution.
24 *
25 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
26 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
27 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
28 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
29 * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
30 * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
31 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
32 * SOFTWARE.
33 */
34
35#include <sys/cdefs.h>
36__FBSDID("$FreeBSD$");
37
38#include <linux/module.h>
39#include <linux/err.h>
40#include <linux/slab.h>
41
42#include <rdma/ib_verbs.h>
43
44#define	IB_CQ_POLL_MAX	16
45/* maximum number of completions per poll loop */
46#define	IB_CQ_POLL_BUDGET 65536
47#define	IB_CQ_POLL_FLAGS (IB_CQ_NEXT_COMP | IB_CQ_REPORT_MISSED_EVENTS)
48
49static void
50ib_cq_poll_work(struct work_struct *work)
51{
52	struct ib_wc ib_wc[IB_CQ_POLL_MAX];
53	struct ib_cq *cq = container_of(work, struct ib_cq, work);
54	int total = 0;
55	int i;
56	int n;
57
58	while (1) {
59		n = ib_poll_cq(cq, IB_CQ_POLL_MAX, ib_wc);
60		for (i = 0; i < n; i++) {
61			struct ib_wc *wc = ib_wc + i;
62
63			if (wc->wr_cqe != NULL)
64				wc->wr_cqe->done(cq, wc);
65		}
66
67		if (n != IB_CQ_POLL_MAX) {
68			if (ib_req_notify_cq(cq, IB_CQ_POLL_FLAGS) > 0)
69				break;
70			else
71				return;
72		}
73		total += n;
74		if (total >= IB_CQ_POLL_BUDGET)
75			break;
76	}
77
78	/* give other work structs a chance */
79	queue_work(ib_comp_wq, &cq->work);
80}
81
82static void
83ib_cq_completion_workqueue(struct ib_cq *cq, void *private)
84{
85	queue_work(ib_comp_wq, &cq->work);
86}
87
88struct ib_cq *
89ib_alloc_cq(struct ib_device *dev, void *private,
90    int nr_cqe, int comp_vector, enum ib_poll_context poll_ctx)
91{
92	struct ib_cq_init_attr cq_attr = {
93		.cqe = nr_cqe,
94		.comp_vector = comp_vector,
95	};
96	struct ib_cq *cq;
97
98	/*
99	 * Check for invalid parameters early on to avoid
100	 * extra error handling code:
101	 */
102	switch (poll_ctx) {
103	case IB_POLL_DIRECT:
104	case IB_POLL_SOFTIRQ:
105	case IB_POLL_WORKQUEUE:
106		break;
107	default:
108		return (ERR_PTR(-EINVAL));
109	}
110
111	cq = dev->create_cq(dev, &cq_attr, NULL, NULL);
112	if (IS_ERR(cq))
113		return (cq);
114
115	cq->device = dev;
116	cq->uobject = NULL;
117	cq->event_handler = NULL;
118	cq->cq_context = private;
119	cq->poll_ctx = poll_ctx;
120	atomic_set(&cq->usecnt, 0);
121
122	switch (poll_ctx) {
123	case IB_POLL_DIRECT:
124		cq->comp_handler = NULL;	/* no hardware completions */
125		break;
126	case IB_POLL_SOFTIRQ:
127	case IB_POLL_WORKQUEUE:
128		cq->comp_handler = ib_cq_completion_workqueue;
129		INIT_WORK(&cq->work, ib_cq_poll_work);
130		ib_req_notify_cq(cq, IB_CQ_NEXT_COMP);
131		break;
132	default:
133		break;
134	}
135	return (cq);
136}
137EXPORT_SYMBOL(ib_alloc_cq);
138
139void
140ib_free_cq(struct ib_cq *cq)
141{
142
143	if (WARN_ON_ONCE(atomic_read(&cq->usecnt) != 0))
144		return;
145
146	switch (cq->poll_ctx) {
147	case IB_POLL_DIRECT:
148		break;
149	case IB_POLL_SOFTIRQ:
150	case IB_POLL_WORKQUEUE:
151		flush_work(&cq->work);
152		break;
153	default:
154		break;
155	}
156
157	(void)cq->device->destroy_cq(cq);
158}
159EXPORT_SYMBOL(ib_free_cq);
160