1/*	$NetBSD: nouveau_nvif_notify.c,v 1.5 2021/12/19 10:51:57 riastradh Exp $	*/
2
3/*
4 * Copyright 2014 Red Hat Inc.
5 *
6 * Permission is hereby granted, free of charge, to any person obtaining a
7 * copy of this software and associated documentation files (the "Software"),
8 * to deal in the Software without restriction, including without limitation
9 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
10 * and/or sell copies of the Software, and to permit persons to whom the
11 * Software is furnished to do so, subject to the following conditions:
12 *
13 * The above copyright notice and this permission notice shall be included in
14 * all copies or substantial portions of the Software.
15 *
16 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
17 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
18 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
19 * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
20 * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
21 * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
22 * OTHER DEALINGS IN THE SOFTWARE.
23 *
24 * Authors: Ben Skeggs <bskeggs@redhat.com>
25 */
26
27#include <sys/cdefs.h>
28__KERNEL_RCSID(0, "$NetBSD: nouveau_nvif_notify.c,v 1.5 2021/12/19 10:51:57 riastradh Exp $");
29
30#include <nvif/client.h>
31#include <nvif/driver.h>
32#include <nvif/notify.h>
33#include <nvif/object.h>
34#include <nvif/ioctl.h>
35#include <nvif/event.h>
36
37static inline int
38nvif_notify_put_(struct nvif_notify *notify)
39{
40	struct nvif_object *object = notify->object;
41	struct {
42		struct nvif_ioctl_v0 ioctl;
43		struct nvif_ioctl_ntfy_put_v0 ntfy;
44	} args = {
45		.ioctl.type = NVIF_IOCTL_V0_NTFY_PUT,
46		.ntfy.index = notify->index,
47	};
48
49	if (atomic_inc_return(&notify->putcnt) != 1)
50		return 0;
51
52	return nvif_object_ioctl(object, &args, sizeof(args), NULL);
53}
54
55int
56nvif_notify_put(struct nvif_notify *notify)
57{
58	if (likely(notify->object) &&
59	    test_and_clear_bit(NVIF_NOTIFY_USER, &notify->flags)) {
60		int ret = nvif_notify_put_(notify);
61		if (test_bit(NVIF_NOTIFY_WORK, &notify->flags))
62			flush_work(&notify->work);
63		return ret;
64	}
65	return 0;
66}
67
68static inline int
69nvif_notify_get_(struct nvif_notify *notify)
70{
71	struct nvif_object *object = notify->object;
72	struct {
73		struct nvif_ioctl_v0 ioctl;
74		struct nvif_ioctl_ntfy_get_v0 ntfy;
75	} args = {
76		.ioctl.type = NVIF_IOCTL_V0_NTFY_GET,
77		.ntfy.index = notify->index,
78	};
79
80	if (atomic_dec_return(&notify->putcnt) != 0)
81		return 0;
82
83	return nvif_object_ioctl(object, &args, sizeof(args), NULL);
84}
85
86int
87nvif_notify_get(struct nvif_notify *notify)
88{
89	if (likely(notify->object) &&
90	    !test_and_set_bit(NVIF_NOTIFY_USER, &notify->flags))
91		return nvif_notify_get_(notify);
92	return 0;
93}
94
95static inline int
96nvif_notify_func(struct nvif_notify *notify, bool keep)
97{
98	int ret = notify->func(notify);
99	if (ret == NVIF_NOTIFY_KEEP ||
100	    !test_and_clear_bit(NVIF_NOTIFY_USER, &notify->flags)) {
101		if (!keep)
102			atomic_dec(&notify->putcnt);
103		else
104			nvif_notify_get_(notify);
105	}
106	return ret;
107}
108
109static void
110nvif_notify_work(struct work_struct *work)
111{
112	struct nvif_notify *notify = container_of(work, typeof(*notify), work);
113	nvif_notify_func(notify, true);
114}
115
116int
117nvif_notify(const void *header, u32 length, const void *data, u32 size)
118{
119	struct nvif_notify *notify = NULL;
120	const union {
121		struct nvif_notify_rep_v0 v0;
122	} *args = header;
123	int ret = NVIF_NOTIFY_DROP;
124
125	if (length == sizeof(args->v0) && args->v0.version == 0) {
126		if (WARN_ON(args->v0.route))
127			return NVIF_NOTIFY_DROP;
128		notify = (void *)(unsigned long)args->v0.token;
129	}
130
131	if (!WARN_ON(notify == NULL)) {
132		struct nvif_client *client = notify->object->client;
133		if (!WARN_ON(notify->size != size)) {
134			atomic_inc(&notify->putcnt);
135			if (test_bit(NVIF_NOTIFY_WORK, &notify->flags)) {
136				memcpy(__UNCONST(notify->data), data, size);
137				schedule_work(&notify->work);
138				return NVIF_NOTIFY_DROP;
139			}
140			notify->data = data;
141			ret = nvif_notify_func(notify, client->driver->keep);
142			notify->data = NULL;
143		}
144	}
145
146	return ret;
147}
148
149int
150nvif_notify_fini(struct nvif_notify *notify)
151{
152	struct nvif_object *object = notify->object;
153	struct {
154		struct nvif_ioctl_v0 ioctl;
155		struct nvif_ioctl_ntfy_del_v0 ntfy;
156	} args = {
157		.ioctl.type = NVIF_IOCTL_V0_NTFY_DEL,
158		.ntfy.index = notify->index,
159	};
160	int ret = nvif_notify_put(notify);
161	if (ret >= 0 && object) {
162		ret = nvif_object_ioctl(object, &args, sizeof(args), NULL);
163		notify->object = NULL;
164		kfree(__UNCONST(notify->data));
165	}
166	return ret;
167}
168
169int
170nvif_notify_init(struct nvif_object *object, int (*func)(struct nvif_notify *),
171		 bool work, u8 event, void *data, u32 size, u32 reply,
172		 struct nvif_notify *notify)
173{
174	struct {
175		struct nvif_ioctl_v0 ioctl;
176		struct nvif_ioctl_ntfy_new_v0 ntfy;
177		struct nvif_notify_req_v0 req;
178	} *args;
179	int ret = -ENOMEM;
180
181	notify->object = object;
182	notify->flags = 0;
183	atomic_set(&notify->putcnt, 1);
184	notify->func = func;
185	notify->data = NULL;
186	notify->size = reply;
187	if (work) {
188		INIT_WORK(&notify->work, nvif_notify_work);
189		set_bit(NVIF_NOTIFY_WORK, &notify->flags);
190		notify->data = kmalloc(notify->size, GFP_KERNEL);
191		if (!notify->data)
192			goto done;
193	}
194
195	if (!(args = kmalloc(sizeof(*args) + size, GFP_KERNEL)))
196		goto done;
197	args->ioctl.version = 0;
198	args->ioctl.type = NVIF_IOCTL_V0_NTFY_NEW;
199	args->ntfy.version = 0;
200	args->ntfy.event = event;
201	args->req.version = 0;
202	args->req.reply = notify->size;
203	args->req.route = 0;
204	args->req.token = (unsigned long)(void *)notify;
205
206	memcpy(args->req.data, data, size);
207	ret = nvif_object_ioctl(object, args, sizeof(*args) + size, NULL);
208	notify->index = args->ntfy.index;
209	kfree(args);
210done:
211	if (ret)
212		nvif_notify_fini(notify);
213	return ret;
214}
215