From: Jonathan Cameron <Jonathan.Cameron@xxxxxxxxxx>
Whilst it is almost always possible to arrange for scan data to be
read directly into a buffer that is suitable for passing to
iio_push_to_buffers_with_timestamp(), there are a few places where
leading data needs to be skipped over.
For these cases introduce a function that will allocate an appropriate
sized and aligned bounce buffer (if not already allocated) and copy
the unaligned data into that before calling
iio_push_to_buffers_with_timestamp() on the bounce buffer.
We tie the lifespace of this buffer to that of the iio_dev.dev
which should ensure no memory leaks occur.
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@xxxxxxxxxx>
---
drivers/iio/industrialio-buffer.c | 36 +++++++++++++++++++++++++++++++
include/linux/iio/buffer.h | 4 ++++
include/linux/iio/iio-opaque.h | 4 ++++
3 files changed, 44 insertions(+)
diff --git a/drivers/iio/industrialio-buffer.c b/drivers/iio/industrialio-buffer.c
index 9a8e16c7e9af..818dfaa73665 100644
--- a/drivers/iio/industrialio-buffer.c
+++ b/drivers/iio/industrialio-buffer.c
@@ -1727,6 +1727,42 @@ int iio_push_to_buffers(struct iio_dev *indio_dev, const void *data)
}
EXPORT_SYMBOL_GPL(iio_push_to_buffers);
+/**
+ * iio_push_to_buffers_with_ts_na() - push to registered buffer,
+ * no alignment or space requirements.
+ * @indio_dev: iio_dev structure for device.
+ * @data: channel data excluding the timestamp.
+ * @data_sz: size of data.
+ * @timestamp: timestamp for the sample data.
+ *
+ * This special variant of iio_push_to_buffers_with_timetamp() does
+ * not require space for the timestamp, or 8 byte alignment of data.
+ * It does however require an allocation on first call and additional
+ * coppies on all calls, so should be avoided if possible
+ */
+int iio_push_to_buffers_with_ts_na(struct iio_dev *indio_dev,
+ const void *data,
+ size_t data_sz,
+ int64_t timestamp)
+{
+ struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
+
+ data_sz = min_t(size_t, indio_dev->scan_bytes, data_sz);
+ if (iio_dev_opaque->bounce_buffer_size != indio_dev->scan_bytes) {
+ iio_dev_opaque->bounce_buffer =
+ devm_krealloc(&indio_dev->dev,
+ iio_dev_opaque->bounce_buffer,
+ indio_dev->scan_bytes, GFP_KERNEL);
+ if (!iio_dev_opaque)
+ return -ENOMEM;
+ }
+ memcpy(iio_dev_opaque->bounce_buffer, data, data_sz);
+ return iio_push_to_buffers_with_timestamp(indio_dev,
+ iio_dev_opaque->bounce_buffer,
+ timestamp);
+}
+EXPORT_SYMBOL_GPL(iio_push_to_buffers_with_ts_na);
+
/**
* iio_buffer_release() - Free a buffer's resources
* @ref: Pointer to the kref embedded in the iio_buffer struct
diff --git a/include/linux/iio/buffer.h b/include/linux/iio/buffer.h
index b6928ac5c63d..4ea9027ad2bf 100644
--- a/include/linux/iio/buffer.h
+++ b/include/linux/iio/buffer.h
@@ -38,6 +38,10 @@ static inline int iio_push_to_buffers_with_timestamp(struct iio_dev *indio_dev,
return iio_push_to_buffers(indio_dev, data);
}
+int iio_push_to_buffers_with_ts_na(struct iio_dev *indio_dev,
+ const void *data, size_t data_sz,
+ int64_t timestamp);
+
bool iio_validate_scan_mask_onehot(struct iio_dev *indio_dev,
const unsigned long *mask);
diff --git a/include/linux/iio/iio-opaque.h b/include/linux/iio/iio-opaque.h
index 32addd5e790e..70ca58e66c0a 100644
--- a/include/linux/iio/iio-opaque.h
+++ b/include/linux/iio/iio-opaque.h
@@ -19,6 +19,8 @@
* @groupcounter: index of next attribute group
* @legacy_scan_el_group: attribute group for legacy scan elements attribute group
* @legacy_buffer_group: attribute group for legacy buffer attributes group
+ * @bounce_buffer: for devices that call iio_push_to_buffers_with_timestamp_na
+ * @bounce_buffer_size: size of currently allocate bounce buffer
* @debugfs_dentry: device specific debugfs dentry
* @cached_reg_addr: cached register address for debugfs reads
* @read_buf: read buffer to be used for the initial reg read
@@ -38,6 +40,8 @@ struct iio_dev_opaque {
int groupcounter;
struct attribute_group legacy_scan_el_group;
struct attribute_group legacy_buffer_group;
+ void *bounce_buffer;
+ size_t bounce_buffer_size;
#if defined(CONFIG_DEBUG_FS)
struct dentry *debugfs_dentry;
unsigned cached_reg_addr;
--
2.31.1
