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authorMatti Vaittinen <mazziesaccount@gmail.com>2023-10-03 12:57:47 +0300
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2023-11-20 11:08:25 +0100
commit168697f15a5387ba3d46d6c06c0ed7428ae57e50 (patch)
tree0109f19e2b64ac277eb89078c7b6323edef00e31 /tools
parenta61c3c647ffd7f01972224456fb4f63e3259d78a (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.c13
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;
}