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| author | Matti Vaittinen <mazziesaccount@gmail.com> | 2023-10-03 12:57:47 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2023-11-20 11:08:25 +0100 |
| commit | 168697f15a5387ba3d46d6c06c0ed7428ae57e50 (patch) | |
| tree | 0109f19e2b64ac277eb89078c7b6323edef00e31 /tools | |
| parent | a61c3c647ffd7f01972224456fb4f63e3259d78a (diff) | |
tools: iio: iio_generic_buffer ensure alignment
[ Upstream commit 2d3dff577dd0ea8fe9637a13822f7603c4a881c8 ]
The iio_generic_buffer can return garbage values when the total size of
scan data is not a multiple of the largest element in the scan. This can be
demonstrated by reading a scan, consisting, for example of one 4-byte and
one 2-byte element, where the 4-byte element is first in the buffer.
The IIO generic buffer code does not take into account the last two
padding bytes that are needed to ensure that the 4-byte data for next
scan is correctly aligned.
Add the padding bytes required to align the next sample with the scan size.
Signed-off-by: Matti Vaittinen <mazziesaccount@gmail.com>
Fixes: e58537ccce73 ("staging: iio: update example application.")
Link: https://lore.kernel.org/r/ZRvlm4ktNLu+qmlf@dc78bmyyyyyyyyyyyyydt-3.rev.dnainternet.fi
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'tools')
| -rw-r--r-- | tools/iio/iio_generic_buffer.c | 13 |
1 files changed, 12 insertions, 1 deletions
diff --git a/tools/iio/iio_generic_buffer.c b/tools/iio/iio_generic_buffer.c index 44bbf80f0cfd..0d0a7a19d6f9 100644 --- a/tools/iio/iio_generic_buffer.c +++ b/tools/iio/iio_generic_buffer.c @@ -54,9 +54,12 @@ enum autochan { static unsigned int size_from_channelarray(struct iio_channel_info *channels, int num_channels) { unsigned int bytes = 0; - int i = 0; + int i = 0, max = 0; + unsigned int misalignment; while (i < num_channels) { + if (channels[i].bytes > max) + max = channels[i].bytes; if (bytes % channels[i].bytes == 0) channels[i].location = bytes; else @@ -66,6 +69,14 @@ static unsigned int size_from_channelarray(struct iio_channel_info *channels, in bytes = channels[i].location + channels[i].bytes; i++; } + /* + * We want the data in next sample to also be properly aligned so + * we'll add padding at the end if needed. Adding padding only + * works for channel data which size is 2^n bytes. + */ + misalignment = bytes % max; + if (misalignment) + bytes += max - misalignment; return bytes; } |