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 int bytes_per_datum, int length)
24 if ((length == 0) || (bytes_per_datum == 0))
27 return __kfifo_alloc((struct __kfifo *)&buf->kf, length,
28 bytes_per_datum, GFP_KERNEL);
31 static int iio_request_update_kfifo(struct iio_buffer *r)
34 struct iio_kfifo *buf = iio_to_kfifo(r);
36 mutex_lock(&buf->user_lock);
37 if (buf->update_needed) {
39 ret = __iio_allocate_kfifo(buf, buf->buffer.bytes_per_datum,
41 buf->update_needed = false;
43 kfifo_reset_out(&buf->kf);
45 mutex_unlock(&buf->user_lock);
50 static int iio_mark_update_needed_kfifo(struct iio_buffer *r)
52 struct iio_kfifo *kf = iio_to_kfifo(r);
53 kf->update_needed = true;
57 static int iio_set_bytes_per_datum_kfifo(struct iio_buffer *r, size_t bpd)
59 if (r->bytes_per_datum != bpd) {
60 r->bytes_per_datum = bpd;
61 iio_mark_update_needed_kfifo(r);
66 static int iio_set_length_kfifo(struct iio_buffer *r, int length)
68 /* Avoid an invalid state */
71 if (r->length != length) {
73 iio_mark_update_needed_kfifo(r);
78 static int iio_store_to_kfifo(struct iio_buffer *r,
82 struct iio_kfifo *kf = iio_to_kfifo(r);
83 ret = kfifo_in(&kf->kf, data, 1);
89 static int iio_read_first_n_kfifo(struct iio_buffer *r,
90 size_t n, char __user *buf)
93 struct iio_kfifo *kf = iio_to_kfifo(r);
95 if (mutex_lock_interruptible(&kf->user_lock))
98 if (!kfifo_initialized(&kf->kf) || n < kfifo_esize(&kf->kf))
101 ret = kfifo_to_user(&kf->kf, buf, n, &copied);
102 mutex_unlock(&kf->user_lock);
109 static size_t iio_kfifo_buf_data_available(struct iio_buffer *r)
111 struct iio_kfifo *kf = iio_to_kfifo(r);
114 mutex_lock(&kf->user_lock);
115 samples = kfifo_len(&kf->kf);
116 mutex_unlock(&kf->user_lock);
121 static void iio_kfifo_buffer_release(struct iio_buffer *buffer)
123 struct iio_kfifo *kf = iio_to_kfifo(buffer);
125 mutex_destroy(&kf->user_lock);
130 static const struct iio_buffer_access_funcs kfifo_access_funcs = {
131 .store_to = &iio_store_to_kfifo,
132 .read_first_n = &iio_read_first_n_kfifo,
133 .data_available = iio_kfifo_buf_data_available,
134 .request_update = &iio_request_update_kfifo,
135 .set_bytes_per_datum = &iio_set_bytes_per_datum_kfifo,
136 .set_length = &iio_set_length_kfifo,
137 .release = &iio_kfifo_buffer_release,
140 struct iio_buffer *iio_kfifo_allocate(void)
142 struct iio_kfifo *kf;
144 kf = kzalloc(sizeof(*kf), GFP_KERNEL);
148 kf->update_needed = true;
149 iio_buffer_init(&kf->buffer);
150 kf->buffer.access = &kfifo_access_funcs;
151 kf->buffer.length = 2;
152 mutex_init(&kf->user_lock);
156 EXPORT_SYMBOL(iio_kfifo_allocate);
158 void iio_kfifo_free(struct iio_buffer *r)
162 EXPORT_SYMBOL(iio_kfifo_free);
164 static void devm_iio_kfifo_release(struct device *dev, void *res)
166 iio_kfifo_free(*(struct iio_buffer **)res);
169 static int devm_iio_kfifo_match(struct device *dev, void *res, void *data)
171 struct iio_buffer **r = res;
173 if (WARN_ON(!r || !*r))
180 * devm_iio_fifo_allocate - Resource-managed iio_kfifo_allocate()
181 * @dev: Device to allocate kfifo buffer for
184 * Pointer to allocated iio_buffer on success, NULL on failure.
186 struct iio_buffer *devm_iio_kfifo_allocate(struct device *dev)
188 struct iio_buffer **ptr, *r;
190 ptr = devres_alloc(devm_iio_kfifo_release, sizeof(*ptr), GFP_KERNEL);
194 r = iio_kfifo_allocate();
197 devres_add(dev, ptr);
204 EXPORT_SYMBOL(devm_iio_kfifo_allocate);
207 * devm_iio_fifo_free - Resource-managed iio_kfifo_free()
208 * @dev: Device the buffer belongs to
209 * @r: The buffer associated with the device
211 void devm_iio_kfifo_free(struct device *dev, struct iio_buffer *r)
213 WARN_ON(devres_release(dev, devm_iio_kfifo_release,
214 devm_iio_kfifo_match, r));
216 EXPORT_SYMBOL(devm_iio_kfifo_free);
218 MODULE_LICENSE("GPL");