1 #include <linux/slab.h>
2 #include <linux/kernel.h>
3 #include <linux/module.h>
4 #include <linux/device.h>
5 #include <linux/workqueue.h>
6 #include <linux/kfifo.h>
7 #include <linux/mutex.h>
8
9 #include "kfifo_buf.h"
10
11 struct iio_kfifo {
12 struct iio_buffer buffer;
13 struct kfifo kf;
14 int update_needed;
15 };
16
17 #define iio_to_kfifo(r) container_of(r, struct iio_kfifo, buffer)
18
__iio_allocate_kfifo(struct iio_kfifo * buf,int bytes_per_datum,int length)19 static inline int __iio_allocate_kfifo(struct iio_kfifo *buf,
20 int bytes_per_datum, int length)
21 {
22 if ((length == 0) || (bytes_per_datum == 0))
23 return -EINVAL;
24
25 __iio_update_buffer(&buf->buffer, bytes_per_datum, length);
26 return kfifo_alloc(&buf->kf, bytes_per_datum*length, GFP_KERNEL);
27 }
28
iio_request_update_kfifo(struct iio_buffer * r)29 static int iio_request_update_kfifo(struct iio_buffer *r)
30 {
31 int ret = 0;
32 struct iio_kfifo *buf = iio_to_kfifo(r);
33
34 if (!buf->update_needed)
35 goto error_ret;
36 kfifo_free(&buf->kf);
37 ret = __iio_allocate_kfifo(buf, buf->buffer.bytes_per_datum,
38 buf->buffer.length);
39 error_ret:
40 return ret;
41 }
42
iio_get_length_kfifo(struct iio_buffer * r)43 static int iio_get_length_kfifo(struct iio_buffer *r)
44 {
45 return r->length;
46 }
47
48 static IIO_BUFFER_ENABLE_ATTR;
49 static IIO_BUFFER_LENGTH_ATTR;
50
51 static struct attribute *iio_kfifo_attributes[] = {
52 &dev_attr_length.attr,
53 &dev_attr_enable.attr,
54 NULL,
55 };
56
57 static struct attribute_group iio_kfifo_attribute_group = {
58 .attrs = iio_kfifo_attributes,
59 .name = "buffer",
60 };
61
iio_get_bytes_per_datum_kfifo(struct iio_buffer * r)62 static int iio_get_bytes_per_datum_kfifo(struct iio_buffer *r)
63 {
64 return r->bytes_per_datum;
65 }
66
iio_mark_update_needed_kfifo(struct iio_buffer * r)67 static int iio_mark_update_needed_kfifo(struct iio_buffer *r)
68 {
69 struct iio_kfifo *kf = iio_to_kfifo(r);
70 kf->update_needed = true;
71 return 0;
72 }
73
iio_set_bytes_per_datum_kfifo(struct iio_buffer * r,size_t bpd)74 static int iio_set_bytes_per_datum_kfifo(struct iio_buffer *r, size_t bpd)
75 {
76 if (r->bytes_per_datum != bpd) {
77 r->bytes_per_datum = bpd;
78 iio_mark_update_needed_kfifo(r);
79 }
80 return 0;
81 }
82
iio_set_length_kfifo(struct iio_buffer * r,int length)83 static int iio_set_length_kfifo(struct iio_buffer *r, int length)
84 {
85 if (r->length != length) {
86 r->length = length;
87 iio_mark_update_needed_kfifo(r);
88 }
89 return 0;
90 }
91
iio_store_to_kfifo(struct iio_buffer * r,u8 * data,s64 timestamp)92 static int iio_store_to_kfifo(struct iio_buffer *r,
93 u8 *data,
94 s64 timestamp)
95 {
96 int ret;
97 struct iio_kfifo *kf = iio_to_kfifo(r);
98 ret = kfifo_in(&kf->kf, data, r->bytes_per_datum);
99 if (ret != r->bytes_per_datum)
100 return -EBUSY;
101 return 0;
102 }
103
iio_read_first_n_kfifo(struct iio_buffer * r,size_t n,char __user * buf)104 static int iio_read_first_n_kfifo(struct iio_buffer *r,
105 size_t n, char __user *buf)
106 {
107 int ret, copied;
108 struct iio_kfifo *kf = iio_to_kfifo(r);
109
110 if (n < r->bytes_per_datum)
111 return -EINVAL;
112
113 n = rounddown(n, r->bytes_per_datum);
114 ret = kfifo_to_user(&kf->kf, buf, n, &copied);
115
116 return copied;
117 }
118
119 static const struct iio_buffer_access_funcs kfifo_access_funcs = {
120 .store_to = &iio_store_to_kfifo,
121 .read_first_n = &iio_read_first_n_kfifo,
122 .request_update = &iio_request_update_kfifo,
123 .get_bytes_per_datum = &iio_get_bytes_per_datum_kfifo,
124 .set_bytes_per_datum = &iio_set_bytes_per_datum_kfifo,
125 .get_length = &iio_get_length_kfifo,
126 .set_length = &iio_set_length_kfifo,
127 };
128
iio_kfifo_allocate(struct iio_dev * indio_dev)129 struct iio_buffer *iio_kfifo_allocate(struct iio_dev *indio_dev)
130 {
131 struct iio_kfifo *kf;
132
133 kf = kzalloc(sizeof *kf, GFP_KERNEL);
134 if (!kf)
135 return NULL;
136 kf->update_needed = true;
137 iio_buffer_init(&kf->buffer);
138 kf->buffer.attrs = &iio_kfifo_attribute_group;
139 kf->buffer.access = &kfifo_access_funcs;
140
141 return &kf->buffer;
142 }
143 EXPORT_SYMBOL(iio_kfifo_allocate);
144
iio_kfifo_free(struct iio_buffer * r)145 void iio_kfifo_free(struct iio_buffer *r)
146 {
147 kfree(iio_to_kfifo(r));
148 }
149 EXPORT_SYMBOL(iio_kfifo_free);
150
151 MODULE_LICENSE("GPL");
152