From: Jonathan Cameron <jic23@kernel.org>
To: linux-iio@vger.kernel.org
Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com>,
Nuno Sa <nuno.sa@analog.com>
Subject: [RFC PATCH 4/4] iio: imu: adis16400: Fix buffer alignment requirements.
Date: Sat, 1 May 2021 18:25:15 +0100 [thread overview]
Message-ID: <20210501172515.513486-5-jic23@kernel.org> (raw)
In-Reply-To: <20210501172515.513486-1-jic23@kernel.org>
From: Jonathan Cameron <Jonathan.Cameron@huawei.com>
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_na() 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: 5075e0720d93 ("iio: imu: adis: generalize burst mode support")
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: Nuno Sa <nuno.sa@analog.com>
---
drivers/iio/imu/adis16400.c | 20 +++++++++++++++-----
1 file changed, 15 insertions(+), 5 deletions(-)
diff --git a/drivers/iio/imu/adis16400.c b/drivers/iio/imu/adis16400.c
index 768aa493a1a6..c6d03a37373b 100644
--- a/drivers/iio/imu/adis16400.c
+++ b/drivers/iio/imu/adis16400.c
@@ -663,13 +663,23 @@ static irqreturn_t adis16400_trigger_handler(int irq, void *p)
spi_setup(st->adis.spi);
}
- 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;
+ /*
+ * 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_na(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_push_to_buffers_with_timestamp(indio_dev, buffer,
- pf->timestamp);
iio_trigger_notify_done(indio_dev->trig);
--
2.31.1
next prev parent reply other threads:[~2021-05-01 17:26 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-05-01 17:25 [RFC PATCH 0/4] IIO: Alignment fixes part 4 - bounce buffers for the hard cases Jonathan Cameron
2021-05-01 17:25 ` [RFC PATCH 1/4] iio: core: Introduce iio_push_to_buffers_with_ts_na() for non aligned case Jonathan Cameron
2021-05-01 19:25 ` Andy Shevchenko
2021-05-01 19:27 ` Andy Shevchenko
2021-05-02 15:37 ` Jonathan Cameron
2021-05-02 15:53 ` Jonathan Cameron
2021-05-02 9:10 ` Sa, Nuno
2021-05-02 16:08 ` Jonathan Cameron
2021-05-03 7:15 ` Sa, Nuno
2021-05-03 7:46 ` Sa, Nuno
2021-05-03 10:34 ` Andy Shevchenko
2021-05-03 10:39 ` Jonathan Cameron
2021-05-03 11:20 ` Sa, Nuno
2021-05-01 17:25 ` [RFC PATCH 2/4] iio: adc: ti-adc108s102: Fix alignment of buffer pushed to iio buffers Jonathan Cameron
2021-05-01 17:25 ` [RFC PATCH 3/4] iio: gyro: mpu3050: Fix alignment and size issues with buffers Jonathan Cameron
2021-05-05 12:58 ` Linus Walleij
2021-05-01 17:25 ` Jonathan Cameron [this message]
2021-05-02 8:52 ` [RFC PATCH 4/4] iio: imu: adis16400: Fix buffer alignment requirements Sa, Nuno
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