[go: nahoru, domu]
sw_sync.c revision 9d1906e61dda982070e3910a04d9cce050f7f1a4 
1/*
2 * drivers/base/sw_sync.c
3 *
4 * Copyright (C) 2012 Google, Inc.
5 *
6 * This software is licensed under the terms of the GNU General Public
7 * License version 2, as published by the Free Software Foundation, and
8 * may be copied, distributed, and modified under those terms.
9 *
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
13 * GNU General Public License for more details.
14 *
15 */
16
17#include <linux/kernel.h>
18#include <linux/file.h>
19#include <linux/fs.h>
20#include <linux/miscdevice.h>
21#include <linux/module.h>
22#include <linux/syscalls.h>
23#include <linux/uaccess.h>
24
25#include "sw_sync.h"
26
27static int sw_sync_cmp(u32 a, u32 b)
28{
29	if (a == b)
30		return 0;
31
32	return ((s32)a - (s32)b) < 0 ? -1 : 1;
33}
34
35struct sync_pt *sw_sync_pt_create(struct sw_sync_timeline *obj, u32 value)
36{
37	struct sw_sync_pt *pt;
38
39	pt = (struct sw_sync_pt *)
40		sync_pt_create(&obj->obj, sizeof(struct sw_sync_pt));
41
42	pt->value = value;
43
44	return (struct sync_pt *)pt;
45}
46
47static struct sync_pt *sw_sync_pt_dup(struct sync_pt *sync_pt)
48{
49	struct sw_sync_pt *pt = (struct sw_sync_pt *) sync_pt;
50	struct sw_sync_timeline *obj =
51		(struct sw_sync_timeline *)sync_pt->parent;
52
53	return (struct sync_pt *) sw_sync_pt_create(obj, pt->value);
54}
55
56static int sw_sync_pt_has_signaled(struct sync_pt *sync_pt)
57{
58	struct sw_sync_pt *pt = (struct sw_sync_pt *)sync_pt;
59	struct sw_sync_timeline *obj =
60		(struct sw_sync_timeline *)sync_pt->parent;
61
62	return sw_sync_cmp(obj->value, pt->value) >= 0;
63}
64
65static int sw_sync_pt_compare(struct sync_pt *a, struct sync_pt *b)
66{
67	struct sw_sync_pt *pt_a = (struct sw_sync_pt *)a;
68	struct sw_sync_pt *pt_b = (struct sw_sync_pt *)b;
69
70	return sw_sync_cmp(pt_a->value, pt_b->value);
71}
72
73struct sync_timeline_ops sw_sync_timeline_ops = {
74	.driver_name = "sw_sync",
75	.dup = sw_sync_pt_dup,
76	.has_signaled = sw_sync_pt_has_signaled,
77	.compare = sw_sync_pt_compare,
78};
79
80
81struct sw_sync_timeline *sw_sync_timeline_create(const char *name)
82{
83	struct sw_sync_timeline *obj = (struct sw_sync_timeline *)
84		sync_timeline_create(&sw_sync_timeline_ops,
85				     sizeof(struct sw_sync_timeline),
86				     name);
87
88	return obj;
89}
90
91void sw_sync_timeline_inc(struct sw_sync_timeline *obj, u32 inc)
92{
93	obj->value += inc;
94
95	sync_timeline_signal(&obj->obj);
96}
97
98
99#ifdef CONFIG_SW_SYNC_USER
100/* *WARNING*
101 *
102 * improper use of this can result in deadlocking kernel drivers from userspace.
103 */
104
105/* opening sw_sync create a new sync obj */
106int sw_sync_open(struct inode *inode, struct file *file)
107{
108	struct sw_sync_timeline *obj;
109	char task_comm[TASK_COMM_LEN];
110
111	get_task_comm(task_comm, current);
112
113	obj = sw_sync_timeline_create(task_comm);
114	if (obj == NULL)
115		return -ENOMEM;
116
117	file->private_data = obj;
118
119	return 0;
120}
121
122int sw_sync_release(struct inode *inode, struct file *file)
123{
124	struct sw_sync_timeline *obj = file->private_data;
125	sync_timeline_destroy(&obj->obj);
126	return 0;
127}
128
129long sw_sync_ioctl_create_fence(struct sw_sync_timeline *obj, unsigned long arg)
130{
131	int fd = get_unused_fd();
132	int err;
133	struct sync_pt *pt;
134	struct sync_fence *fence;
135	struct sw_sync_create_fence_data data;
136
137	if (copy_from_user(&data, (void __user *)arg, sizeof(data)))
138		return -EFAULT;
139
140	pt = sw_sync_pt_create(obj, data.value);
141	if (pt == NULL) {
142		err = -ENOMEM;
143		goto err;
144	}
145
146	data.name[sizeof(data.name) - 1] = '\0';
147	fence = sync_fence_create(data.name, pt);
148	if (fence == NULL) {
149		sync_pt_free(pt);
150		err = -ENOMEM;
151		goto err;
152	}
153
154	data.fence = fd;
155	if (copy_to_user((void __user *)arg, &data, sizeof(data))) {
156		sync_fence_put(fence);
157		err = -EFAULT;
158		goto err;
159	}
160
161	sync_fence_install(fence, fd);
162
163	return 0;
164
165err:
166	put_unused_fd(fd);
167	return err;
168}
169
170long sw_sync_ioctl_inc(struct sw_sync_timeline *obj, unsigned long arg)
171{
172	u32 value;
173
174	if (copy_from_user(&value, (void __user *)arg, sizeof(value)))
175		return -EFAULT;
176
177	sw_sync_timeline_inc(obj, value);
178
179	return 0;
180}
181
182long sw_sync_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
183{
184	struct sw_sync_timeline *obj = file->private_data;
185
186	switch (cmd) {
187	case SW_SYNC_IOC_CREATE_FENCE:
188		return sw_sync_ioctl_create_fence(obj, arg);
189
190	case SW_SYNC_IOC_INC:
191		return sw_sync_ioctl_inc(obj, arg);
192
193	default:
194		return -ENOTTY;
195	}
196}
197
198static const struct file_operations sw_sync_fops = {
199	.owner = THIS_MODULE,
200	.open = sw_sync_open,
201	.release = sw_sync_release,
202	.unlocked_ioctl = sw_sync_ioctl,
203};
204
205static struct miscdevice sw_sync_dev = {
206	.minor	= MISC_DYNAMIC_MINOR,
207	.name	= "sw_sync",
208	.fops	= &sw_sync_fops,
209};
210
211int __init sw_sync_device_init(void)
212{
213	return misc_register(&sw_sync_dev);
214}
215
216void __exit sw_sync_device_remove(void)
217{
218	misc_deregister(&sw_sync_dev);
219}
220
221module_init(sw_sync_device_init);
222module_exit(sw_sync_device_remove);
223
224#endif /* CONFIG_SW_SYNC_USER */
225