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