tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
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#include <linux/iio/kfifo_buf.h>
9#include <linux/sched.h>
10#include <linux/poll.h>
11
12struct iio_kfifo {
13 struct iio_buffer buffer;
14 struct kfifo kf;
15 struct mutex user_lock;
16 int update_needed;
17};
18
19#define iio_to_kfifo(r) container_of(r, struct iio_kfifo, buffer)
20
21static inline int __iio_allocate_kfifo(struct iio_kfifo *buf,
22 int bytes_per_datum, int length)
23{
24 if ((length == 0) || (bytes_per_datum == 0))
25 return -EINVAL;
26
27 return __kfifo_alloc((struct __kfifo *)&buf->kf, length,
28 bytes_per_datum, GFP_KERNEL);
29}
30
31static int iio_request_update_kfifo(struct iio_buffer *r)
32{
33 int ret = 0;
34 struct iio_kfifo *buf = iio_to_kfifo(r);
35
36 mutex_lock(&buf->user_lock);
37 if (buf->update_needed) {
38 kfifo_free(&buf->kf);
39 ret = __iio_allocate_kfifo(buf, buf->buffer.bytes_per_datum,
40 buf->buffer.length);
41 if (ret >= 0)
42 buf->update_needed = false;
43 } else {
44 kfifo_reset_out(&buf->kf);
45 }
46 mutex_unlock(&buf->user_lock);
47
48 return ret;
49}
50
51static int iio_mark_update_needed_kfifo(struct iio_buffer *r)
52{
53 struct iio_kfifo *kf = iio_to_kfifo(r);
54 kf->update_needed = true;
55 return 0;
56}
57
58static int iio_set_bytes_per_datum_kfifo(struct iio_buffer *r, size_t bpd)
59{
60 if (r->bytes_per_datum != bpd) {
61 r->bytes_per_datum = bpd;
62 iio_mark_update_needed_kfifo(r);
63 }
64 return 0;
65}
66
67static int iio_set_length_kfifo(struct iio_buffer *r, int length)
68{
69 /* Avoid an invalid state */
70 if (length < 2)
71 length = 2;
72 if (r->length != length) {
73 r->length = length;
74 iio_mark_update_needed_kfifo(r);
75 }
76 return 0;
77}
78
79static int iio_store_to_kfifo(struct iio_buffer *r,
80 const void *data)
81{
82 int ret;
83 struct iio_kfifo *kf = iio_to_kfifo(r);
84 ret = kfifo_in(&kf->kf, data, 1);
85 if (ret != 1)
86 return -EBUSY;
87 return 0;
88}
89
90static int iio_read_first_n_kfifo(struct iio_buffer *r,
91 size_t n, char __user *buf)
92{
93 int ret, copied;
94 struct iio_kfifo *kf = iio_to_kfifo(r);
95
96 if (mutex_lock_interruptible(&kf->user_lock))
97 return -ERESTARTSYS;
98
99 if (!kfifo_initialized(&kf->kf) || n < kfifo_esize(&kf->kf))
100 ret = -EINVAL;
101 else
102 ret = kfifo_to_user(&kf->kf, buf, n, &copied);
103 mutex_unlock(&kf->user_lock);
104 if (ret < 0)
105 return ret;
106
107 return copied;
108}
109
110static size_t iio_kfifo_buf_data_available(struct iio_buffer *r)
111{
112 struct iio_kfifo *kf = iio_to_kfifo(r);
113 size_t samples;
114
115 mutex_lock(&kf->user_lock);
116 samples = kfifo_len(&kf->kf);
117 mutex_unlock(&kf->user_lock);
118
119 return samples;
120}
121
122static void iio_kfifo_buffer_release(struct iio_buffer *buffer)
123{
124 struct iio_kfifo *kf = iio_to_kfifo(buffer);
125
126 mutex_destroy(&kf->user_lock);
127 kfifo_free(&kf->kf);
128 kfree(kf);
129}
130
131static const struct iio_buffer_access_funcs kfifo_access_funcs = {
132 .store_to = &iio_store_to_kfifo,
133 .read_first_n = &iio_read_first_n_kfifo,
134 .data_available = iio_kfifo_buf_data_available,
135 .request_update = &iio_request_update_kfifo,
136 .set_bytes_per_datum = &iio_set_bytes_per_datum_kfifo,
137 .set_length = &iio_set_length_kfifo,
138 .release = &iio_kfifo_buffer_release,
139
140 .modes = INDIO_BUFFER_SOFTWARE | INDIO_BUFFER_TRIGGERED,
141};
142
143struct iio_buffer *iio_kfifo_allocate(void)
144{
145 struct iio_kfifo *kf;
146
147 kf = kzalloc(sizeof(*kf), GFP_KERNEL);
148 if (!kf)
149 return NULL;
150
151 kf->update_needed = true;
152 iio_buffer_init(&kf->buffer);
153 kf->buffer.access = &kfifo_access_funcs;
154 kf->buffer.length = 2;
155 mutex_init(&kf->user_lock);
156
157 return &kf->buffer;
158}
159EXPORT_SYMBOL(iio_kfifo_allocate);
160
161void iio_kfifo_free(struct iio_buffer *r)
162{
163 iio_buffer_put(r);
164}
165EXPORT_SYMBOL(iio_kfifo_free);
166
167static void devm_iio_kfifo_release(struct device *dev, void *res)
168{
169 iio_kfifo_free(*(struct iio_buffer **)res);
170}
171
172static int devm_iio_kfifo_match(struct device *dev, void *res, void *data)
173{
174 struct iio_buffer **r = res;
175
176 if (WARN_ON(!r || !*r))
177 return 0;
178
179 return *r == data;
180}
181
182/**
183 * devm_iio_fifo_allocate - Resource-managed iio_kfifo_allocate()
184 * @dev: Device to allocate kfifo buffer for
185 *
186 * RETURNS:
187 * Pointer to allocated iio_buffer on success, NULL on failure.
188 */
189struct iio_buffer *devm_iio_kfifo_allocate(struct device *dev)
190{
191 struct iio_buffer **ptr, *r;
192
193 ptr = devres_alloc(devm_iio_kfifo_release, sizeof(*ptr), GFP_KERNEL);
194 if (!ptr)
195 return NULL;
196
197 r = iio_kfifo_allocate();
198 if (r) {
199 *ptr = r;
200 devres_add(dev, ptr);
201 } else {
202 devres_free(ptr);
203 }
204
205 return r;
206}
207EXPORT_SYMBOL(devm_iio_kfifo_allocate);
208
209/**
210 * devm_iio_fifo_free - Resource-managed iio_kfifo_free()
211 * @dev: Device the buffer belongs to
212 * @r: The buffer associated with the device
213 */
214void devm_iio_kfifo_free(struct device *dev, struct iio_buffer *r)
215{
216 WARN_ON(devres_release(dev, devm_iio_kfifo_release,
217 devm_iio_kfifo_match, r));
218}
219EXPORT_SYMBOL(devm_iio_kfifo_free);
220
221MODULE_LICENSE("GPL");