On Fri, 12 Feb 2021 12:20:18 +0200
Alexandru Ardelean <alexandru.ardelean@xxxxxxxxxx> wrote:
> From: Lars-Peter Clausen <lars@xxxxxxxxxx>
>
> Add output buffer support to the kfifo buffer implementation.
>
> The implementation is straight forward and mostly just wraps the kfifo
> API to provide the required operations.
>
> Signed-off-by: Lars-Peter Clausen <lars@xxxxxxxxxx>
> Signed-off-by: Alexandru Ardelean <alexandru.ardelean@xxxxxxxxxx>
Nice. For some reason I thought it would be more complex than this :)
Jonathan
> ---
> drivers/iio/buffer/kfifo_buf.c | 50 ++++++++++++++++++++++++++++++++++
> 1 file changed, 50 insertions(+)
>
> diff --git a/drivers/iio/buffer/kfifo_buf.c b/drivers/iio/buffer/kfifo_buf.c
> index 1359abed3b31..6e055176f969 100644
> --- a/drivers/iio/buffer/kfifo_buf.c
> +++ b/drivers/iio/buffer/kfifo_buf.c
> @@ -138,10 +138,60 @@ static void iio_kfifo_buffer_release(struct iio_buffer *buffer)
> kfree(kf);
> }
>
> +static size_t iio_kfifo_buf_space_available(struct iio_buffer *r)
> +{
> + struct iio_kfifo *kf = iio_to_kfifo(r);
> + size_t avail;
> +
> + mutex_lock(&kf->user_lock);
> + avail = kfifo_avail(&kf->kf);
> + mutex_unlock(&kf->user_lock);
> +
> + return avail;
> +}
> +
> +static int iio_kfifo_remove_from(struct iio_buffer *r, void *data)
> +{
> + int ret;
> + struct iio_kfifo *kf = iio_to_kfifo(r);
> +
> + if (kfifo_size(&kf->kf) < r->bytes_per_datum)
> + return -EBUSY;
> +
> + ret = kfifo_out(&kf->kf, data, r->bytes_per_datum);
> + if (ret != r->bytes_per_datum)
> + return -EBUSY;
> +
> + wake_up_interruptible_poll(&r->pollq, POLLOUT | POLLWRNORM);
> +
> + return 0;
> +}
> +
> +static int iio_kfifo_write(struct iio_buffer *r, size_t n,
> + const char __user *buf)
> +{
> + struct iio_kfifo *kf = iio_to_kfifo(r);
> + int ret, copied;
> +
> + mutex_lock(&kf->user_lock);
> + if (!kfifo_initialized(&kf->kf) || n < kfifo_esize(&kf->kf))
> + ret = -EINVAL;
> + else
> + ret = kfifo_from_user(&kf->kf, buf, n, &copied);
> + mutex_unlock(&kf->user_lock);
> + if (ret)
> + return ret;
> +
> + return copied;
> +}
> +
> static const struct iio_buffer_access_funcs kfifo_access_funcs = {
> .store_to = &iio_store_to_kfifo,
> .read = &iio_read_kfifo,
> .data_available = iio_kfifo_buf_data_available,
> + .remove_from = &iio_kfifo_remove_from,
> + .write = &iio_kfifo_write,
> + .space_available = &iio_kfifo_buf_space_available,
> .request_update = &iio_request_update_kfifo,
> .set_bytes_per_datum = &iio_set_bytes_per_datum_kfifo,
> .set_length = &iio_set_length_kfifo,
