diff options
| author | Octavian Purdila <octavian.purdila@intel.com> | 2015-06-05 15:56:47 +0300 |
|---|---|---|
| committer | Jonathan Cameron <jic23@kernel.org> | 2015-06-21 16:51:13 +0300 |
| commit | c6f67a1f55a7f8a8373068ca07553bd2b2731949 (patch) | |
| tree | 936323b1e9e9d2ef184f35fc32f5abd459b0572e /drivers/iio/industrialio-buffer.c | |
| parent | e20008ed931b9bdd90d1a3fd8c9ef9307547f4ed (diff) | |
| download | linux-c6f67a1f55a7f8a8373068ca07553bd2b2731949.tar.xz | |
iio: allow userspace to flush the hwfifo with non-blocking reads
This patch changes the semantics of non-blocking reads so that a
hardware fifo flush is triggered if the available data in the device
buffer is less then the requested size.
This allows userspace to accurately generate hardware fifo flushes, by
doing a non-blocking read with a size greater then the sum of the
device buffer and hardware fifo size.
Signed-off-by: Octavian Purdila <octavian.purdila@intel.com>
Reviewed-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
Diffstat (limited to 'drivers/iio/industrialio-buffer.c')
| -rw-r--r-- | drivers/iio/industrialio-buffer.c | 18 |
1 files changed, 9 insertions, 9 deletions
diff --git a/drivers/iio/industrialio-buffer.c b/drivers/iio/industrialio-buffer.c index 6eee1b044c60..f72be48e650c 100644 --- a/drivers/iio/industrialio-buffer.c +++ b/drivers/iio/industrialio-buffer.c @@ -71,8 +71,9 @@ static bool iio_buffer_ready(struct iio_dev *indio_dev, struct iio_buffer *buf, if (avail >= to_wait) { /* force a flush for non-blocking reads */ - if (!to_wait && !avail && to_flush) - iio_buffer_flush_hwfifo(indio_dev, buf, to_flush); + if (!to_wait && avail < to_flush) + iio_buffer_flush_hwfifo(indio_dev, buf, + to_flush - avail); return true; } @@ -100,8 +101,7 @@ ssize_t iio_buffer_read_first_n_outer(struct file *filp, char __user *buf, struct iio_dev *indio_dev = filp->private_data; struct iio_buffer *rb = indio_dev->buffer; size_t datum_size; - size_t to_wait = 0; - size_t to_read; + size_t to_wait; int ret; if (!indio_dev->info) @@ -119,14 +119,14 @@ ssize_t iio_buffer_read_first_n_outer(struct file *filp, char __user *buf, if (!datum_size) return 0; - to_read = min_t(size_t, n / datum_size, rb->watermark); - - if (!(filp->f_flags & O_NONBLOCK)) - to_wait = to_read; + if (filp->f_flags & O_NONBLOCK) + to_wait = 0; + else + to_wait = min_t(size_t, n / datum_size, rb->watermark); do { ret = wait_event_interruptible(rb->pollq, - iio_buffer_ready(indio_dev, rb, to_wait, to_read)); + iio_buffer_ready(indio_dev, rb, to_wait, n / datum_size)); if (ret) return ret; |