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>
13 struct iio_buffer buffer;
15 struct mutex user_lock;
19 #define iio_to_kfifo(r) container_of(r, struct iio_kfifo, buffer)
21 static inline int __iio_allocate_kfifo(struct iio_kfifo *buf,
22 size_t bytes_per_datum, unsigned int length)
24 if ((length == 0) || (bytes_per_datum == 0))
28 * Make sure we don't overflow an unsigned int after kfifo rounds up to
29 * the next power of 2.
31 if (roundup_pow_of_two(length) > UINT_MAX / bytes_per_datum)
34 return __kfifo_alloc((struct __kfifo *)&buf->kf, length,
35 bytes_per_datum, GFP_KERNEL);
38 static int iio_request_update_kfifo(struct iio_buffer *r)
41 struct iio_kfifo *buf = iio_to_kfifo(r);
43 mutex_lock(&buf->user_lock);
44 if (buf->update_needed) {
46 ret = __iio_allocate_kfifo(buf, buf->buffer.bytes_per_datum,
49 buf->update_needed = false;
51 kfifo_reset_out(&buf->kf);
53 mutex_unlock(&buf->user_lock);
58 static int iio_mark_update_needed_kfifo(struct iio_buffer *r)
60 struct iio_kfifo *kf = iio_to_kfifo(r);
61 kf->update_needed = true;
65 static int iio_set_bytes_per_datum_kfifo(struct iio_buffer *r, size_t bpd)
67 if (r->bytes_per_datum != bpd) {
68 r->bytes_per_datum = bpd;
69 iio_mark_update_needed_kfifo(r);
74 static int iio_set_length_kfifo(struct iio_buffer *r, unsigned int length)
76 /* Avoid an invalid state */
79 if (r->length != length) {
81 iio_mark_update_needed_kfifo(r);
86 static int iio_store_to_kfifo(struct iio_buffer *r,
90 struct iio_kfifo *kf = iio_to_kfifo(r);
91 ret = kfifo_in(&kf->kf, data, 1);
97 static int iio_read_first_n_kfifo(struct iio_buffer *r,
98 size_t n, char __user *buf)
101 struct iio_kfifo *kf = iio_to_kfifo(r);
103 if (mutex_lock_interruptible(&kf->user_lock))
106 if (!kfifo_initialized(&kf->kf) || n < kfifo_esize(&kf->kf))
109 ret = kfifo_to_user(&kf->kf, buf, n, &copied);
110 mutex_unlock(&kf->user_lock);
117 static size_t iio_kfifo_buf_data_available(struct iio_buffer *r)
119 struct iio_kfifo *kf = iio_to_kfifo(r);
122 mutex_lock(&kf->user_lock);
123 samples = kfifo_len(&kf->kf);
124 mutex_unlock(&kf->user_lock);
129 static void iio_kfifo_buffer_release(struct iio_buffer *buffer)
131 struct iio_kfifo *kf = iio_to_kfifo(buffer);
133 mutex_destroy(&kf->user_lock);
138 static const struct iio_buffer_access_funcs kfifo_access_funcs = {
139 .store_to = &iio_store_to_kfifo,
140 .read_first_n = &iio_read_first_n_kfifo,
141 .data_available = iio_kfifo_buf_data_available,
142 .request_update = &iio_request_update_kfifo,
143 .set_bytes_per_datum = &iio_set_bytes_per_datum_kfifo,
144 .set_length = &iio_set_length_kfifo,
145 .release = &iio_kfifo_buffer_release,
147 .modes = INDIO_BUFFER_SOFTWARE | INDIO_BUFFER_TRIGGERED,
150 struct iio_buffer *iio_kfifo_allocate(void)
152 struct iio_kfifo *kf;
154 kf = kzalloc(sizeof(*kf), GFP_KERNEL);
158 kf->update_needed = true;
159 iio_buffer_init(&kf->buffer);
160 kf->buffer.access = &kfifo_access_funcs;
161 kf->buffer.length = 2;
162 mutex_init(&kf->user_lock);
166 EXPORT_SYMBOL(iio_kfifo_allocate);
168 void iio_kfifo_free(struct iio_buffer *r)
172 EXPORT_SYMBOL(iio_kfifo_free);
174 static void devm_iio_kfifo_release(struct device *dev, void *res)
176 iio_kfifo_free(*(struct iio_buffer **)res);
179 static int devm_iio_kfifo_match(struct device *dev, void *res, void *data)
181 struct iio_buffer **r = res;
183 if (WARN_ON(!r || !*r))
190 * devm_iio_fifo_allocate - Resource-managed iio_kfifo_allocate()
191 * @dev: Device to allocate kfifo buffer for
194 * Pointer to allocated iio_buffer on success, NULL on failure.
196 struct iio_buffer *devm_iio_kfifo_allocate(struct device *dev)
198 struct iio_buffer **ptr, *r;
200 ptr = devres_alloc(devm_iio_kfifo_release, sizeof(*ptr), GFP_KERNEL);
204 r = iio_kfifo_allocate();
207 devres_add(dev, ptr);
214 EXPORT_SYMBOL(devm_iio_kfifo_allocate);
217 * devm_iio_fifo_free - Resource-managed iio_kfifo_free()
218 * @dev: Device the buffer belongs to
219 * @r: The buffer associated with the device
221 void devm_iio_kfifo_free(struct device *dev, struct iio_buffer *r)
223 WARN_ON(devres_release(dev, devm_iio_kfifo_release,
224 devm_iio_kfifo_match, r));
226 EXPORT_SYMBOL(devm_iio_kfifo_free);
228 MODULE_LICENSE("GPL");