projects/linux·blob master · refs

272 lines · 6.3 KiB

1// SPDX-License-Identifier: GPL-2.0-only
2#include <linux/slab.h>
3#include <linux/kernel.h>
4#include <linux/module.h>
5#include <linux/device.h>
6#include <linux/workqueue.h>
7#include <linux/kfifo.h>
8#include <linux/mutex.h>
9#include <linux/iio/iio.h>
10#include <linux/iio/buffer.h>
11#include <linux/iio/kfifo_buf.h>
12#include <linux/iio/buffer_impl.h>
13#include <linux/sched.h>
14#include <linux/poll.h>
15
16struct iio_kfifo {
17 struct iio_buffer buffer;
18 struct kfifo kf;
19 struct mutex user_lock;
20 int update_needed;
21};
22
23#define iio_to_kfifo(r) container_of(r, struct iio_kfifo, buffer)
24
25static inline int __iio_allocate_kfifo(struct iio_kfifo *buf,
26 size_t bytes_per_datum, unsigned int length)
27{
28 if ((length == 0) || (bytes_per_datum == 0))
29 return -EINVAL;
30
31 /*
32 * Make sure we don't overflow an unsigned int after kfifo rounds up to
33 * the next power of 2.
34 */
35 if (roundup_pow_of_two(length) > UINT_MAX / bytes_per_datum)
36 return -EINVAL;
37
38 return __kfifo_alloc((struct __kfifo *)&buf->kf, length,
39 bytes_per_datum, GFP_KERNEL);
40}
41
42static int iio_request_update_kfifo(struct iio_buffer *r)
43{
44 int ret = 0;
45 struct iio_kfifo *buf = iio_to_kfifo(r);
46
47 mutex_lock(&buf->user_lock);
48 if (buf->update_needed) {
49 kfifo_free(&buf->kf);
50 ret = __iio_allocate_kfifo(buf, buf->buffer.bytes_per_datum,
51 buf->buffer.length);
52 if (ret >= 0)
53 buf->update_needed = false;
54 } else {
55 kfifo_reset_out(&buf->kf);
56 }
57 mutex_unlock(&buf->user_lock);
58
59 return ret;
60}
61
62static int iio_mark_update_needed_kfifo(struct iio_buffer *r)
63{
64 struct iio_kfifo *kf = iio_to_kfifo(r);
65 kf->update_needed = true;
66 return 0;
67}
68
69static int iio_set_bytes_per_datum_kfifo(struct iio_buffer *r, size_t bpd)
70{
71 if (r->bytes_per_datum != bpd) {
72 r->bytes_per_datum = bpd;
73 iio_mark_update_needed_kfifo(r);
74 }
75 return 0;
76}
77
78static int iio_set_length_kfifo(struct iio_buffer *r, unsigned int length)
79{
80 /* Avoid an invalid state */
81 if (length < 2)
82 length = 2;
83 if (r->length != length) {
84 r->length = length;
85 iio_mark_update_needed_kfifo(r);
86 }
87 return 0;
88}
89
90static int iio_store_to_kfifo(struct iio_buffer *r,
91 const void *data)
92{
93 int ret;
94 struct iio_kfifo *kf = iio_to_kfifo(r);
95 ret = kfifo_in(&kf->kf, data, 1);
96 if (ret != 1)
97 return -EBUSY;
98 return 0;
99}
100
101static int iio_read_kfifo(struct iio_buffer *r, size_t n, char __user *buf)
102{
103 int ret, copied;
104 struct iio_kfifo *kf = iio_to_kfifo(r);
105
106 if (mutex_lock_interruptible(&kf->user_lock))
107 return -ERESTARTSYS;
108
109 if (!kfifo_initialized(&kf->kf) || n < kfifo_esize(&kf->kf))
110 ret = -EINVAL;
111 else
112 ret = kfifo_to_user(&kf->kf, buf, n, &copied);
113 mutex_unlock(&kf->user_lock);
114 if (ret < 0)
115 return ret;
116
117 return copied;
118}
119
120static size_t iio_kfifo_buf_data_available(struct iio_buffer *r)
121{
122 struct iio_kfifo *kf = iio_to_kfifo(r);
123 size_t samples;
124
125 mutex_lock(&kf->user_lock);
126 samples = kfifo_len(&kf->kf);
127 mutex_unlock(&kf->user_lock);
128
129 return samples;
130}
131
132static void iio_kfifo_buffer_release(struct iio_buffer *buffer)
133{
134 struct iio_kfifo *kf = iio_to_kfifo(buffer);
135
136 mutex_destroy(&kf->user_lock);
137 kfifo_free(&kf->kf);
138 kfree(kf);
139}
140
141static size_t iio_kfifo_buf_space_available(struct iio_buffer *r)
142{
143 struct iio_kfifo *kf = iio_to_kfifo(r);
144 size_t avail;
145
146 mutex_lock(&kf->user_lock);
147 avail = kfifo_avail(&kf->kf);
148 mutex_unlock(&kf->user_lock);
149
150 return avail;
151}
152
153static int iio_kfifo_remove_from(struct iio_buffer *r, void *data)
154{
155 int ret;
156 struct iio_kfifo *kf = iio_to_kfifo(r);
157
158 if (kfifo_size(&kf->kf) < 1)
159 return -EBUSY;
160
161 ret = kfifo_out(&kf->kf, data, 1);
162 if (ret != 1)
163 return -EBUSY;
164
165 wake_up_interruptible_poll(&r->pollq, EPOLLOUT | EPOLLWRNORM);
166
167 return 0;
168}
169
170static int iio_kfifo_write(struct iio_buffer *r, size_t n,
171 const char __user *buf)
172{
173 struct iio_kfifo *kf = iio_to_kfifo(r);
174 int ret, copied;
175
176 mutex_lock(&kf->user_lock);
177 if (!kfifo_initialized(&kf->kf) || n < kfifo_esize(&kf->kf))
178 ret = -EINVAL;
179 else
180 ret = kfifo_from_user(&kf->kf, buf, n, &copied);
181 mutex_unlock(&kf->user_lock);
182 if (ret)
183 return ret;
184
185 return copied;
186}
187
188static const struct iio_buffer_access_funcs kfifo_access_funcs = {
189 .store_to = &iio_store_to_kfifo,
190 .read = &iio_read_kfifo,
191 .data_available = iio_kfifo_buf_data_available,
192 .remove_from = &iio_kfifo_remove_from,
193 .write = &iio_kfifo_write,
194 .space_available = &iio_kfifo_buf_space_available,
195 .request_update = &iio_request_update_kfifo,
196 .set_bytes_per_datum = &iio_set_bytes_per_datum_kfifo,
197 .set_length = &iio_set_length_kfifo,
198 .release = &iio_kfifo_buffer_release,
199
200 .modes = INDIO_BUFFER_SOFTWARE | INDIO_BUFFER_TRIGGERED,
201};
202
203struct iio_buffer *iio_kfifo_allocate(void)
204{
205 struct iio_kfifo *kf;
206
207 kf = kzalloc_obj(*kf);
208 if (!kf)
209 return NULL;
210
211 kf->update_needed = true;
212 iio_buffer_init(&kf->buffer);
213 kf->buffer.access = &kfifo_access_funcs;
214 kf->buffer.length = 2;
215 mutex_init(&kf->user_lock);
216
217 return &kf->buffer;
218}
219EXPORT_SYMBOL(iio_kfifo_allocate);
220
221void iio_kfifo_free(struct iio_buffer *r)
222{
223 iio_buffer_put(r);
224}
225EXPORT_SYMBOL(iio_kfifo_free);
226
227static void devm_iio_kfifo_release(void *buffer)
228{
229 iio_kfifo_free(buffer);
230}
231
232/**
233 * devm_iio_kfifo_buffer_setup_ext - Allocate a kfifo buffer & attach it to an IIO device
234 * @dev: Device object to which to attach the life-time of this kfifo buffer
235 * @indio_dev: The device the buffer should be attached to
236 * @setup_ops: The setup_ops required to configure the HW part of the buffer (optional)
237 * @buffer_attrs: Extra sysfs buffer attributes for this IIO buffer
238 *
239 * This function allocates a kfifo buffer via iio_kfifo_allocate() and
240 * attaches it to the IIO device via iio_device_attach_buffer().
241 * This is meant to be a bit of a short-hand/helper function as there are a few
242 * drivers that seem to do this.
243 *
244 * Return: 0 on success, negative error code on failure.
245 */
246int devm_iio_kfifo_buffer_setup_ext(struct device *dev,
247 struct iio_dev *indio_dev,
248 const struct iio_buffer_setup_ops *setup_ops,
249 const struct iio_dev_attr **buffer_attrs)
250{
251 struct iio_buffer *buffer;
252 int ret;
253
254 buffer = iio_kfifo_allocate();
255 if (!buffer)
256 return -ENOMEM;
257
258 ret = devm_add_action_or_reset(dev, devm_iio_kfifo_release, buffer);
259 if (ret)
260 return ret;
261
262 indio_dev->modes |= INDIO_BUFFER_SOFTWARE;
263 indio_dev->setup_ops = setup_ops;
264
265 buffer->attrs = buffer_attrs;
266
267 return iio_device_attach_buffer(indio_dev, buffer);
268}
269EXPORT_SYMBOL_GPL(devm_iio_kfifo_buffer_setup_ext);
270
271MODULE_DESCRIPTION("Industrial I/O buffering based on kfifo");
272MODULE_LICENSE("GPL");