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/init.h>
19 #include <linux/export.h>
20 #include <linux/file.h>
21 #include <linux/fs.h>
22 #include <linux/miscdevice.h>
23 #include <linux/syscalls.h>
24 #include <linux/uaccess.h>
25
26 #include "sw_sync.h"
27
sw_sync_cmp(u32 a,u32 b)28 static int sw_sync_cmp(u32 a, u32 b)
29 {
30 if (a == b)
31 return 0;
32
33 return ((s32)a - (s32)b) < 0 ? -1 : 1;
34 }
35
sw_sync_pt_create(struct sw_sync_timeline * obj,u32 value)36 struct sync_pt *sw_sync_pt_create(struct sw_sync_timeline *obj, u32 value)
37 {
38 struct sw_sync_pt *pt;
39
40 pt = (struct sw_sync_pt *)
41 sync_pt_create(&obj->obj, sizeof(struct sw_sync_pt));
42
43 pt->value = value;
44
45 return (struct sync_pt *)pt;
46 }
47 EXPORT_SYMBOL(sw_sync_pt_create);
48
sw_sync_pt_dup(struct sync_pt * sync_pt)49 static struct sync_pt *sw_sync_pt_dup(struct sync_pt *sync_pt)
50 {
51 struct sw_sync_pt *pt = (struct sw_sync_pt *)sync_pt;
52 struct sw_sync_timeline *obj =
53 (struct sw_sync_timeline *)sync_pt_parent(sync_pt);
54
55 return (struct sync_pt *)sw_sync_pt_create(obj, pt->value);
56 }
57
sw_sync_pt_has_signaled(struct sync_pt * sync_pt)58 static int sw_sync_pt_has_signaled(struct sync_pt *sync_pt)
59 {
60 struct sw_sync_pt *pt = (struct sw_sync_pt *)sync_pt;
61 struct sw_sync_timeline *obj =
62 (struct sw_sync_timeline *)sync_pt_parent(sync_pt);
63
64 return sw_sync_cmp(obj->value, pt->value) >= 0;
65 }
66
sw_sync_pt_compare(struct sync_pt * a,struct sync_pt * b)67 static int sw_sync_pt_compare(struct sync_pt *a, struct sync_pt *b)
68 {
69 struct sw_sync_pt *pt_a = (struct sw_sync_pt *)a;
70 struct sw_sync_pt *pt_b = (struct sw_sync_pt *)b;
71
72 return sw_sync_cmp(pt_a->value, pt_b->value);
73 }
74
sw_sync_fill_driver_data(struct sync_pt * sync_pt,void * data,int size)75 static int sw_sync_fill_driver_data(struct sync_pt *sync_pt,
76 void *data, int size)
77 {
78 struct sw_sync_pt *pt = (struct sw_sync_pt *)sync_pt;
79
80 if (size < sizeof(pt->value))
81 return -ENOMEM;
82
83 memcpy(data, &pt->value, sizeof(pt->value));
84
85 return sizeof(pt->value);
86 }
87
sw_sync_timeline_value_str(struct sync_timeline * sync_timeline,char * str,int size)88 static void sw_sync_timeline_value_str(struct sync_timeline *sync_timeline,
89 char *str, int size)
90 {
91 struct sw_sync_timeline *timeline =
92 (struct sw_sync_timeline *)sync_timeline;
93 snprintf(str, size, "%d", timeline->value);
94 }
95
sw_sync_pt_value_str(struct sync_pt * sync_pt,char * str,int size)96 static void sw_sync_pt_value_str(struct sync_pt *sync_pt,
97 char *str, int size)
98 {
99 struct sw_sync_pt *pt = (struct sw_sync_pt *)sync_pt;
100
101 snprintf(str, size, "%d", pt->value);
102 }
103
104 static struct sync_timeline_ops sw_sync_timeline_ops = {
105 .driver_name = "sw_sync",
106 .dup = sw_sync_pt_dup,
107 .has_signaled = sw_sync_pt_has_signaled,
108 .compare = sw_sync_pt_compare,
109 .fill_driver_data = sw_sync_fill_driver_data,
110 .timeline_value_str = sw_sync_timeline_value_str,
111 .pt_value_str = sw_sync_pt_value_str,
112 };
113
sw_sync_timeline_create(const char * name)114 struct sw_sync_timeline *sw_sync_timeline_create(const char *name)
115 {
116 struct sw_sync_timeline *obj = (struct sw_sync_timeline *)
117 sync_timeline_create(&sw_sync_timeline_ops,
118 sizeof(struct sw_sync_timeline),
119 name);
120
121 return obj;
122 }
123 EXPORT_SYMBOL(sw_sync_timeline_create);
124
sw_sync_timeline_inc(struct sw_sync_timeline * obj,u32 inc)125 void sw_sync_timeline_inc(struct sw_sync_timeline *obj, u32 inc)
126 {
127 obj->value += inc;
128
129 sync_timeline_signal(&obj->obj);
130 }
131 EXPORT_SYMBOL(sw_sync_timeline_inc);
132
133 #ifdef CONFIG_SW_SYNC_USER
134 /* *WARNING*
135 *
136 * improper use of this can result in deadlocking kernel drivers from userspace.
137 */
138
139 /* opening sw_sync create a new sync obj */
sw_sync_open(struct inode * inode,struct file * file)140 static int sw_sync_open(struct inode *inode, struct file *file)
141 {
142 struct sw_sync_timeline *obj;
143 char task_comm[TASK_COMM_LEN];
144
145 get_task_comm(task_comm, current);
146
147 obj = sw_sync_timeline_create(task_comm);
148 if (!obj)
149 return -ENOMEM;
150
151 file->private_data = obj;
152
153 return 0;
154 }
155
sw_sync_release(struct inode * inode,struct file * file)156 static int sw_sync_release(struct inode *inode, struct file *file)
157 {
158 struct sw_sync_timeline *obj = file->private_data;
159
160 sync_timeline_destroy(&obj->obj);
161 return 0;
162 }
163
sw_sync_ioctl_create_fence(struct sw_sync_timeline * obj,unsigned long arg)164 static long sw_sync_ioctl_create_fence(struct sw_sync_timeline *obj,
165 unsigned long arg)
166 {
167 int fd = get_unused_fd_flags(O_CLOEXEC);
168 int err;
169 struct sync_pt *pt;
170 struct sync_fence *fence;
171 struct sw_sync_create_fence_data data;
172
173 if (fd < 0)
174 return fd;
175
176 if (copy_from_user(&data, (void __user *)arg, sizeof(data))) {
177 err = -EFAULT;
178 goto err;
179 }
180
181 pt = sw_sync_pt_create(obj, data.value);
182 if (!pt) {
183 err = -ENOMEM;
184 goto err;
185 }
186
187 data.name[sizeof(data.name) - 1] = '\0';
188 fence = sync_fence_create(data.name, pt);
189 if (!fence) {
190 sync_pt_free(pt);
191 err = -ENOMEM;
192 goto err;
193 }
194
195 data.fence = fd;
196 if (copy_to_user((void __user *)arg, &data, sizeof(data))) {
197 sync_fence_put(fence);
198 err = -EFAULT;
199 goto err;
200 }
201
202 sync_fence_install(fence, fd);
203
204 return 0;
205
206 err:
207 put_unused_fd(fd);
208 return err;
209 }
210
sw_sync_ioctl_inc(struct sw_sync_timeline * obj,unsigned long arg)211 static long sw_sync_ioctl_inc(struct sw_sync_timeline *obj, unsigned long arg)
212 {
213 u32 value;
214
215 if (copy_from_user(&value, (void __user *)arg, sizeof(value)))
216 return -EFAULT;
217
218 sw_sync_timeline_inc(obj, value);
219
220 return 0;
221 }
222
sw_sync_ioctl(struct file * file,unsigned int cmd,unsigned long arg)223 static long sw_sync_ioctl(struct file *file, unsigned int cmd,
224 unsigned long arg)
225 {
226 struct sw_sync_timeline *obj = file->private_data;
227
228 switch (cmd) {
229 case SW_SYNC_IOC_CREATE_FENCE:
230 return sw_sync_ioctl_create_fence(obj, arg);
231
232 case SW_SYNC_IOC_INC:
233 return sw_sync_ioctl_inc(obj, arg);
234
235 default:
236 return -ENOTTY;
237 }
238 }
239
240 static const struct file_operations sw_sync_fops = {
241 .owner = THIS_MODULE,
242 .open = sw_sync_open,
243 .release = sw_sync_release,
244 .unlocked_ioctl = sw_sync_ioctl,
245 .compat_ioctl = sw_sync_ioctl,
246 };
247
248 static struct miscdevice sw_sync_dev = {
249 .minor = MISC_DYNAMIC_MINOR,
250 .name = "sw_sync",
251 .fops = &sw_sync_fops,
252 };
253
sw_sync_device_init(void)254 static int __init sw_sync_device_init(void)
255 {
256 return misc_register(&sw_sync_dev);
257 }
258 device_initcall(sw_sync_device_init);
259
260 #endif /* CONFIG_SW_SYNC_USER */
261