linux/drivers/iio/buffer/kfifo_buf.c
Lars-Peter Clausen 8548a63b37 iio: Move generic buffer implementations to sub-directory
For generic IIO trigger implementations we already have a sub-directory,
but the generic buffer implementations currently reside in the IIO
top-level directory. The main reason is that things have historically grown
into this form.

With more generic buffer implementations on its way now is the perfect time
to clean this up and introduce a sub-directory for generic buffer
implementations to avoid too much clutter in the top-level directory.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
2015-08-16 10:51:21 +01:00

222 lines
4.8 KiB
C

#include <linux/slab.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/device.h>
#include <linux/workqueue.h>
#include <linux/kfifo.h>
#include <linux/mutex.h>
#include <linux/iio/kfifo_buf.h>
#include <linux/sched.h>
#include <linux/poll.h>
struct iio_kfifo {
struct iio_buffer buffer;
struct kfifo kf;
struct mutex user_lock;
int update_needed;
};
#define iio_to_kfifo(r) container_of(r, struct iio_kfifo, buffer)
static inline int __iio_allocate_kfifo(struct iio_kfifo *buf,
int bytes_per_datum, int length)
{
if ((length == 0) || (bytes_per_datum == 0))
return -EINVAL;
return __kfifo_alloc((struct __kfifo *)&buf->kf, length,
bytes_per_datum, GFP_KERNEL);
}
static int iio_request_update_kfifo(struct iio_buffer *r)
{
int ret = 0;
struct iio_kfifo *buf = iio_to_kfifo(r);
mutex_lock(&buf->user_lock);
if (buf->update_needed) {
kfifo_free(&buf->kf);
ret = __iio_allocate_kfifo(buf, buf->buffer.bytes_per_datum,
buf->buffer.length);
if (ret >= 0)
buf->update_needed = false;
} else {
kfifo_reset_out(&buf->kf);
}
mutex_unlock(&buf->user_lock);
return ret;
}
static int iio_mark_update_needed_kfifo(struct iio_buffer *r)
{
struct iio_kfifo *kf = iio_to_kfifo(r);
kf->update_needed = true;
return 0;
}
static int iio_set_bytes_per_datum_kfifo(struct iio_buffer *r, size_t bpd)
{
if (r->bytes_per_datum != bpd) {
r->bytes_per_datum = bpd;
iio_mark_update_needed_kfifo(r);
}
return 0;
}
static int iio_set_length_kfifo(struct iio_buffer *r, int length)
{
/* Avoid an invalid state */
if (length < 2)
length = 2;
if (r->length != length) {
r->length = length;
iio_mark_update_needed_kfifo(r);
}
return 0;
}
static int iio_store_to_kfifo(struct iio_buffer *r,
const void *data)
{
int ret;
struct iio_kfifo *kf = iio_to_kfifo(r);
ret = kfifo_in(&kf->kf, data, 1);
if (ret != 1)
return -EBUSY;
return 0;
}
static int iio_read_first_n_kfifo(struct iio_buffer *r,
size_t n, char __user *buf)
{
int ret, copied;
struct iio_kfifo *kf = iio_to_kfifo(r);
if (mutex_lock_interruptible(&kf->user_lock))
return -ERESTARTSYS;
if (!kfifo_initialized(&kf->kf) || n < kfifo_esize(&kf->kf))
ret = -EINVAL;
else
ret = kfifo_to_user(&kf->kf, buf, n, &copied);
mutex_unlock(&kf->user_lock);
if (ret < 0)
return ret;
return copied;
}
static size_t iio_kfifo_buf_data_available(struct iio_buffer *r)
{
struct iio_kfifo *kf = iio_to_kfifo(r);
size_t samples;
mutex_lock(&kf->user_lock);
samples = kfifo_len(&kf->kf);
mutex_unlock(&kf->user_lock);
return samples;
}
static void iio_kfifo_buffer_release(struct iio_buffer *buffer)
{
struct iio_kfifo *kf = iio_to_kfifo(buffer);
mutex_destroy(&kf->user_lock);
kfifo_free(&kf->kf);
kfree(kf);
}
static const struct iio_buffer_access_funcs kfifo_access_funcs = {
.store_to = &iio_store_to_kfifo,
.read_first_n = &iio_read_first_n_kfifo,
.data_available = iio_kfifo_buf_data_available,
.request_update = &iio_request_update_kfifo,
.set_bytes_per_datum = &iio_set_bytes_per_datum_kfifo,
.set_length = &iio_set_length_kfifo,
.release = &iio_kfifo_buffer_release,
.modes = INDIO_BUFFER_SOFTWARE | INDIO_BUFFER_TRIGGERED,
};
struct iio_buffer *iio_kfifo_allocate(void)
{
struct iio_kfifo *kf;
kf = kzalloc(sizeof(*kf), GFP_KERNEL);
if (!kf)
return NULL;
kf->update_needed = true;
iio_buffer_init(&kf->buffer);
kf->buffer.access = &kfifo_access_funcs;
kf->buffer.length = 2;
mutex_init(&kf->user_lock);
return &kf->buffer;
}
EXPORT_SYMBOL(iio_kfifo_allocate);
void iio_kfifo_free(struct iio_buffer *r)
{
iio_buffer_put(r);
}
EXPORT_SYMBOL(iio_kfifo_free);
static void devm_iio_kfifo_release(struct device *dev, void *res)
{
iio_kfifo_free(*(struct iio_buffer **)res);
}
static int devm_iio_kfifo_match(struct device *dev, void *res, void *data)
{
struct iio_buffer **r = res;
if (WARN_ON(!r || !*r))
return 0;
return *r == data;
}
/**
* devm_iio_fifo_allocate - Resource-managed iio_kfifo_allocate()
* @dev: Device to allocate kfifo buffer for
*
* RETURNS:
* Pointer to allocated iio_buffer on success, NULL on failure.
*/
struct iio_buffer *devm_iio_kfifo_allocate(struct device *dev)
{
struct iio_buffer **ptr, *r;
ptr = devres_alloc(devm_iio_kfifo_release, sizeof(*ptr), GFP_KERNEL);
if (!ptr)
return NULL;
r = iio_kfifo_allocate();
if (r) {
*ptr = r;
devres_add(dev, ptr);
} else {
devres_free(ptr);
}
return r;
}
EXPORT_SYMBOL(devm_iio_kfifo_allocate);
/**
* devm_iio_fifo_free - Resource-managed iio_kfifo_free()
* @dev: Device the buffer belongs to
* @r: The buffer associated with the device
*/
void devm_iio_kfifo_free(struct device *dev, struct iio_buffer *r)
{
WARN_ON(devres_release(dev, devm_iio_kfifo_release,
devm_iio_kfifo_match, r));
}
EXPORT_SYMBOL(devm_iio_kfifo_free);
MODULE_LICENSE("GPL");