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>
17 struct iio_buffer buffer;
19 struct mutex user_lock;
23 #define iio_to_kfifo(r) container_of(r, struct iio_kfifo, buffer)
25 static inline int __iio_allocate_kfifo(struct iio_kfifo *buf,
26 size_t bytes_per_datum, unsigned int length)
28 if ((length == 0) || (bytes_per_datum == 0))
32 * Make sure we don't overflow an unsigned int after kfifo rounds up to
33 * the next power of 2.
35 if (roundup_pow_of_two(length) > UINT_MAX / bytes_per_datum)
38 return __kfifo_alloc((struct __kfifo *)&buf->kf, length,
39 bytes_per_datum, GFP_KERNEL);
42 static int iio_request_update_kfifo(struct iio_buffer *r)
45 struct iio_kfifo *buf = iio_to_kfifo(r);
47 mutex_lock(&buf->user_lock);
48 if (buf->update_needed) {
50 ret = __iio_allocate_kfifo(buf, buf->buffer.bytes_per_datum,
53 buf->update_needed = false;
55 kfifo_reset_out(&buf->kf);
57 mutex_unlock(&buf->user_lock);
62 static int iio_mark_update_needed_kfifo(struct iio_buffer *r)
64 struct iio_kfifo *kf = iio_to_kfifo(r);
65 kf->update_needed = true;
69 static int iio_set_bytes_per_datum_kfifo(struct iio_buffer *r, size_t bpd)
71 if (r->bytes_per_datum != bpd) {
72 r->bytes_per_datum = bpd;
73 iio_mark_update_needed_kfifo(r);
78 static int iio_set_length_kfifo(struct iio_buffer *r, unsigned int length)
80 /* Avoid an invalid state */
83 if (r->length != length) {
85 iio_mark_update_needed_kfifo(r);
90 static int iio_store_to_kfifo(struct iio_buffer *r,
94 struct iio_kfifo *kf = iio_to_kfifo(r);
95 ret = kfifo_in(&kf->kf, data, 1);
101 static int iio_read_kfifo(struct iio_buffer *r, size_t n, char __user *buf)
104 struct iio_kfifo *kf = iio_to_kfifo(r);
106 if (mutex_lock_interruptible(&kf->user_lock))
109 if (!kfifo_initialized(&kf->kf) || n < kfifo_esize(&kf->kf))
112 ret = kfifo_to_user(&kf->kf, buf, n, &copied);
113 mutex_unlock(&kf->user_lock);
120 static size_t iio_kfifo_buf_data_available(struct iio_buffer *r)
122 struct iio_kfifo *kf = iio_to_kfifo(r);
125 mutex_lock(&kf->user_lock);
126 samples = kfifo_len(&kf->kf);
127 mutex_unlock(&kf->user_lock);
132 static void iio_kfifo_buffer_release(struct iio_buffer *buffer)
134 struct iio_kfifo *kf = iio_to_kfifo(buffer);
136 mutex_destroy(&kf->user_lock);
141 static const struct iio_buffer_access_funcs kfifo_access_funcs = {
142 .store_to = &iio_store_to_kfifo,
143 .read = &iio_read_kfifo,
144 .data_available = iio_kfifo_buf_data_available,
145 .request_update = &iio_request_update_kfifo,
146 .set_bytes_per_datum = &iio_set_bytes_per_datum_kfifo,
147 .set_length = &iio_set_length_kfifo,
148 .release = &iio_kfifo_buffer_release,
150 .modes = INDIO_BUFFER_SOFTWARE | INDIO_BUFFER_TRIGGERED,
153 struct iio_buffer *iio_kfifo_allocate(void)
155 struct iio_kfifo *kf;
157 kf = kzalloc(sizeof(*kf), GFP_KERNEL);
161 kf->update_needed = true;
162 iio_buffer_init(&kf->buffer);
163 kf->buffer.access = &kfifo_access_funcs;
164 kf->buffer.length = 2;
165 mutex_init(&kf->user_lock);
169 EXPORT_SYMBOL(iio_kfifo_allocate);
171 void iio_kfifo_free(struct iio_buffer *r)
175 EXPORT_SYMBOL(iio_kfifo_free);
177 static void devm_iio_kfifo_release(struct device *dev, void *res)
179 iio_kfifo_free(*(struct iio_buffer **)res);
183 * devm_iio_kfifo_allocate - Resource-managed iio_kfifo_allocate()
184 * @dev: Device to allocate kfifo buffer for
187 * Pointer to allocated iio_buffer on success, NULL on failure.
189 static struct iio_buffer *devm_iio_kfifo_allocate(struct device *dev)
191 struct iio_buffer **ptr, *r;
193 ptr = devres_alloc(devm_iio_kfifo_release, sizeof(*ptr), GFP_KERNEL);
197 r = iio_kfifo_allocate();
200 devres_add(dev, ptr);
209 * devm_iio_kfifo_buffer_setup_ext - Allocate a kfifo buffer & attach it to an IIO device
210 * @dev: Device object to which to attach the life-time of this kfifo buffer
211 * @indio_dev: The device the buffer should be attached to
212 * @mode_flags: The mode flags for this buffer (INDIO_BUFFER_SOFTWARE and/or
213 * INDIO_BUFFER_TRIGGERED).
214 * @setup_ops: The setup_ops required to configure the HW part of the buffer (optional)
215 * @buffer_attrs: Extra sysfs buffer attributes for this IIO buffer
217 * This function allocates a kfifo buffer via devm_iio_kfifo_allocate() and
218 * attaches it to the IIO device via iio_device_attach_buffer().
219 * This is meant to be a bit of a short-hand/helper function as there are a few
220 * drivers that seem to do this.
222 int devm_iio_kfifo_buffer_setup_ext(struct device *dev,
223 struct iio_dev *indio_dev,
225 const struct iio_buffer_setup_ops *setup_ops,
226 const struct attribute **buffer_attrs)
228 struct iio_buffer *buffer;
233 buffer = devm_iio_kfifo_allocate(dev);
237 mode_flags &= kfifo_access_funcs.modes;
239 indio_dev->modes |= mode_flags;
240 indio_dev->setup_ops = setup_ops;
242 buffer->attrs = buffer_attrs;
244 return iio_device_attach_buffer(indio_dev, buffer);
246 EXPORT_SYMBOL_GPL(devm_iio_kfifo_buffer_setup_ext);
248 MODULE_LICENSE("GPL");