Commit d7a83bc3 authored Jun 13, 2021 by Jonathan Cameron

iio: imu: adis16400: Fix buffer alignment requirements.



iio_push_to_buffers_with_timestamp() requires that the buffer
is 8 byte alignment to ensure an inserted timestamp is naturally aligned.

This requirement was not met here when burst mode is in use beause
of a leading u16. Use the new iio_push_to_buffers_with_ts_unaligned()
function that has more relaxed requirements.

It is somewhat complex to access that actual data length, but a
safe bound can be found by using scan_bytes - sizeof(timestamp) so that
is used in this path.

More efficient approaches exist, but this ensure correctness at the
cost of using a bounce buffer.

Fixes: 5075e072 ("iio: imu: adis: generalize burst mode support")
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: Nuno Sá <nuno.sa@analog.com>
Link: https://lore.kernel.org/r/20210613151039.569883-5-jic23@kernel.org

parent b5ca2046

drivers/iio/imu/adis16400.c

+15 −5

Original line number	Diff line number	Diff line
		@@ -641,13 +641,23 @@ static irqreturn_t adis16400_trigger_handler(int irq, void *p)
		if (ret)
		dev_err(&adis->spi->dev, "Failed to read data: %d\n", ret);

		if (st->variant->flags & ADIS16400_BURST_DIAG_STAT)
		if (st->variant->flags & ADIS16400_BURST_DIAG_STAT) {
		buffer = adis->buffer + sizeof(u16);
		else
		buffer = adis->buffer;

		iio_push_to_buffers_with_timestamp(indio_dev, buffer,
		/*
		* The size here is always larger than, or equal to the true
		* size of the channel data. This may result in a larger copy
		* than necessary, but as the target buffer will be
		* buffer->scan_bytes this will be safe.
		*/
		iio_push_to_buffers_with_ts_unaligned(indio_dev, buffer,
		indio_dev->scan_bytes - sizeof(pf->timestamp),
		pf->timestamp);
		} else {
		iio_push_to_buffers_with_timestamp(indio_dev,
		adis->buffer,
		pf->timestamp);
		}


		iio_trigger_notify_done(indio_dev->trig);