1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
|
// SPDX-License-Identifier: GPL-2.0-only
#include <linux/slab.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/device.h>
#include <linux/workqueue.h>
#include <linux/kfifo.h>
#include <linux/mutex.h>
#include <linux/iio/iio.h>
#include <linux/iio/buffer.h>
#include <linux/iio/kfifo_buf.h>
#include <linux/iio/buffer_impl.h>
#include <linux/sched.h>
#include <linux/poll.h>
struct iio_kfifo {
struct iio_buffer buffer;
struct kfifo kf;
struct mutex user_lock;
int update_needed;
};
#define iio_to_kfifo(r) container_of(r, struct iio_kfifo, buffer)
static inline int __iio_allocate_kfifo(struct iio_kfifo *buf,
size_t bytes_per_datum, unsigned int length)
{
if ((length == 0) || (bytes_per_datum == 0))
return -EINVAL;
/*
* Make sure we don't overflow an unsigned int after kfifo rounds up to
* the next power of 2.
*/
if (roundup_pow_of_two(length) > UINT_MAX / bytes_per_datum)
return -EINVAL;
return __kfifo_alloc((struct __kfifo *)&buf->kf, length,
bytes_per_datum, GFP_KERNEL);
}
static int iio_request_update_kfifo(struct iio_buffer *r)
{
int ret = 0;
struct iio_kfifo *buf = iio_to_kfifo(r);
mutex_lock(&buf->user_lock);
if (buf->update_needed) {
kfifo_free(&buf->kf);
ret = __iio_allocate_kfifo(buf, buf->buffer.bytes_per_datum,
buf->buffer.length);
if (ret >= 0)
buf->update_needed = false;
} else {
kfifo_reset_out(&buf->kf);
}
mutex_unlock(&buf->user_lock);
return ret;
}
static int iio_mark_update_needed_kfifo(struct iio_buffer *r)
{
struct iio_kfifo *kf = iio_to_kfifo(r);
kf->update_needed = true;
return 0;
}
static int iio_set_bytes_per_datum_kfifo(struct iio_buffer *r, size_t bpd)
{
if (r->bytes_per_datum != bpd) {
r->bytes_per_datum = bpd;
iio_mark_update_needed_kfifo(r);
}
return 0;
}
static int iio_set_length_kfifo(struct iio_buffer *r, unsigned int length)
{
/* Avoid an invalid state */
if (length < 2)
length = 2;
if (r->length != length) {
r->length = length;
iio_mark_update_needed_kfifo(r);
}
return 0;
}
static int iio_store_to_kfifo(struct iio_buffer *r,
const void *data)
{
int ret;
struct iio_kfifo *kf = iio_to_kfifo(r);
ret = kfifo_in(&kf->kf, data, 1);
if (ret != 1)
return -EBUSY;
return 0;
}
static int iio_read_first_n_kfifo(struct iio_buffer *r,
size_t n, char __user *buf)
{
int ret, copied;
struct iio_kfifo *kf = iio_to_kfifo(r);
if (mutex_lock_interruptible(&kf->user_lock))
return -ERESTARTSYS;
if (!kfifo_initialized(&kf->kf) || n < kfifo_esize(&kf->kf))
ret = -EINVAL;
else
ret = kfifo_to_user(&kf->kf, buf, n, &copied);
mutex_unlock(&kf->user_lock);
if (ret < 0)
return ret;
return copied;
}
static size_t iio_kfifo_buf_data_available(struct iio_buffer *r)
{
struct iio_kfifo *kf = iio_to_kfifo(r);
size_t samples;
mutex_lock(&kf->user_lock);
samples = kfifo_len(&kf->kf);
mutex_unlock(&kf->user_lock);
return samples;
}
static void iio_kfifo_buffer_release(struct iio_buffer *buffer)
{
struct iio_kfifo *kf = iio_to_kfifo(buffer);
mutex_destroy(&kf->user_lock);
kfifo_free(&kf->kf);
kfree(kf);
}
static const struct iio_buffer_access_funcs kfifo_access_funcs = {
.store_to = &iio_store_to_kfifo,
.read_first_n = &iio_read_first_n_kfifo,
.data_available = iio_kfifo_buf_data_available,
.request_update = &iio_request_update_kfifo,
.set_bytes_per_datum = &iio_set_bytes_per_datum_kfifo,
.set_length = &iio_set_length_kfifo,
.release = &iio_kfifo_buffer_release,
.modes = INDIO_BUFFER_SOFTWARE | INDIO_BUFFER_TRIGGERED,
};
struct iio_buffer *iio_kfifo_allocate(void)
{
struct iio_kfifo *kf;
kf = kzalloc(sizeof(*kf), GFP_KERNEL);
if (!kf)
return NULL;
kf->update_needed = true;
iio_buffer_init(&kf->buffer);
kf->buffer.access = &kfifo_access_funcs;
kf->buffer.length = 2;
mutex_init(&kf->user_lock);
return &kf->buffer;
}
EXPORT_SYMBOL(iio_kfifo_allocate);
void iio_kfifo_free(struct iio_buffer *r)
{
iio_buffer_put(r);
}
EXPORT_SYMBOL(iio_kfifo_free);
static void devm_iio_kfifo_release(struct device *dev, void *res)
{
iio_kfifo_free(*(struct iio_buffer **)res);
}
static int devm_iio_kfifo_match(struct device *dev, void *res, void *data)
{
struct iio_buffer **r = res;
if (WARN_ON(!r || !*r))
return 0;
return *r == data;
}
/**
* devm_iio_fifo_allocate - Resource-managed iio_kfifo_allocate()
* @dev: Device to allocate kfifo buffer for
*
* RETURNS:
* Pointer to allocated iio_buffer on success, NULL on failure.
*/
struct iio_buffer *devm_iio_kfifo_allocate(struct device *dev)
{
struct iio_buffer **ptr, *r;
ptr = devres_alloc(devm_iio_kfifo_release, sizeof(*ptr), GFP_KERNEL);
if (!ptr)
return NULL;
r = iio_kfifo_allocate();
if (r) {
*ptr = r;
devres_add(dev, ptr);
} else {
devres_free(ptr);
}
return r;
}
EXPORT_SYMBOL(devm_iio_kfifo_allocate);
/**
* devm_iio_fifo_free - Resource-managed iio_kfifo_free()
* @dev: Device the buffer belongs to
* @r: The buffer associated with the device
*/
void devm_iio_kfifo_free(struct device *dev, struct iio_buffer *r)
{
WARN_ON(devres_release(dev, devm_iio_kfifo_release,
devm_iio_kfifo_match, r));
}
EXPORT_SYMBOL(devm_iio_kfifo_free);
MODULE_LICENSE("GPL");
|
