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
|
#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/kfifo_buf.h>
#include <linux/sched.h>
#include <linux/poll.h>
struct iio_kfifo {
struct iio_buffer buffer;
struct kfifo kf;
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,
int bytes_per_datum, int length)
{
if ((length == 0) || (bytes_per_datum == 0))
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);
if (!buf->update_needed)
goto error_ret;
kfifo_free(&buf->kf);
ret = __iio_allocate_kfifo(buf, buf->buffer.bytes_per_datum,
buf->buffer.length);
r->stufftoread = false;
error_ret:
return ret;
}
static int iio_get_length_kfifo(struct iio_buffer *r)
{
return r->length;
}
static IIO_BUFFER_ENABLE_ATTR;
static IIO_BUFFER_LENGTH_ATTR;
static struct attribute *iio_kfifo_attributes[] = {
&dev_attr_length.attr,
&dev_attr_enable.attr,
NULL,
};
static struct attribute_group iio_kfifo_attribute_group = {
.attrs = iio_kfifo_attributes,
.name = "buffer",
};
static int iio_get_bytes_per_datum_kfifo(struct iio_buffer *r)
{
return r->bytes_per_datum;
}
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, 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;
r->stufftoread = true;
wake_up_interruptible_poll(&r->pollq, POLLIN | POLLRDNORM);
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 (n < r->bytes_per_datum || r->bytes_per_datum == 0)
return -EINVAL;
ret = kfifo_to_user(&kf->kf, buf, n, &copied);
if (ret < 0)
return ret;
if (kfifo_is_empty(&kf->kf))
r->stufftoread = false;
/* verify it is still empty to avoid race */
if (!kfifo_is_empty(&kf->kf))
r->stufftoread = true;
return copied;
}
static void iio_kfifo_buffer_release(struct iio_buffer *buffer)
{
kfree(iio_to_kfifo(buffer));
}
static const struct iio_buffer_access_funcs kfifo_access_funcs = {
.store_to = &iio_store_to_kfifo,
.read_first_n = &iio_read_first_n_kfifo,
.request_update = &iio_request_update_kfifo,
.get_bytes_per_datum = &iio_get_bytes_per_datum_kfifo,
.set_bytes_per_datum = &iio_set_bytes_per_datum_kfifo,
.get_length = &iio_get_length_kfifo,
.set_length = &iio_set_length_kfifo,
.release = &iio_kfifo_buffer_release,
};
struct iio_buffer *iio_kfifo_allocate(struct iio_dev *indio_dev)
{
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.attrs = &iio_kfifo_attribute_group;
kf->buffer.access = &kfifo_access_funcs;
kf->buffer.length = 2;
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);
MODULE_LICENSE("GPL");
|
