On 29/05/15 17:14, Lars-Peter Clausen wrote:
> In hardware mode we can not use the software demuxer, this means that the
> selected scan mask needs to match one of the available scan masks exactly.
>
> It also means that all attached buffers need to use the same scan mask.
> Given that when operating in hardware mode there is typically only a single
> buffer attached to the device this not an issue. Add a sanity check to make
> sure that only a single buffer is attached in hardware mode nevertheless.
>
That pretty much sums up why devices supporting only hardware buffers
are probably not going to be a long term feature!
Mind you for fast devices we may want to allow forced bypassing of the
demux (i.e. a hardware buffer).
Out of curiosity is this series a precursor to another hardware buffered
device or just a useful intellectual exercise?
Applied.
> Signed-off-by: Lars-Peter Clausen <lars@xxxxxxxxxx>
> ---
> drivers/iio/industrialio-buffer.c | 25 ++++++++++++++++++++-----
> 1 file changed, 20 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/iio/industrialio-buffer.c b/drivers/iio/industrialio-buffer.c
> index 4250e97..e174fcc 100644
> --- a/drivers/iio/industrialio-buffer.c
> +++ b/drivers/iio/industrialio-buffer.c
> @@ -239,13 +239,19 @@ static ssize_t iio_scan_el_show(struct device *dev,
> /* Note NULL used as error indicator as it doesn't make sense. */
> static const unsigned long *iio_scan_mask_match(const unsigned long *av_masks,
> unsigned int masklength,
> - const unsigned long *mask)
> + const unsigned long *mask,
> + bool strict)
> {
> if (bitmap_empty(mask, masklength))
> return NULL;
> while (*av_masks) {
> - if (bitmap_subset(mask, av_masks, masklength))
> - return av_masks;
> + if (strict) {
> + if (bitmap_equal(mask, av_masks, masklength))
> + return av_masks;
> + } else {
> + if (bitmap_subset(mask, av_masks, masklength))
> + return av_masks;
> + }
> av_masks += BITS_TO_LONGS(masklength);
> }
> return NULL;
> @@ -295,7 +301,7 @@ static int iio_scan_mask_set(struct iio_dev *indio_dev,
> if (indio_dev->available_scan_masks) {
> mask = iio_scan_mask_match(indio_dev->available_scan_masks,
> indio_dev->masklength,
> - trialmask);
> + trialmask, false);
> if (!mask)
> goto err_invalid_mask;
> }
> @@ -602,6 +608,7 @@ static int iio_verify_update(struct iio_dev *indio_dev,
> {
> unsigned long *compound_mask;
> const unsigned long *scan_mask;
> + bool strict_scanmask = false;
> struct iio_buffer *buffer;
> bool scan_timestamp;
> unsigned int modes;
> @@ -631,7 +638,14 @@ static int iio_verify_update(struct iio_dev *indio_dev,
> if ((modes & INDIO_BUFFER_TRIGGERED) && indio_dev->trig) {
> config->mode = INDIO_BUFFER_TRIGGERED;
> } else if (modes & INDIO_BUFFER_HARDWARE) {
> + /*
> + * Keep things simple for now and only allow a single buffer to
> + * be connected in hardware mode.
> + */
> + if (insert_buffer && !list_empty(&indio_dev->buffer_list))
> + return -EINVAL;
> config->mode = INDIO_BUFFER_HARDWARE;
> + strict_scanmask = true;
> } else if (modes & INDIO_BUFFER_SOFTWARE) {
> config->mode = INDIO_BUFFER_SOFTWARE;
> } else {
> @@ -666,7 +680,8 @@ static int iio_verify_update(struct iio_dev *indio_dev,
> if (indio_dev->available_scan_masks) {
> scan_mask = iio_scan_mask_match(indio_dev->available_scan_masks,
> indio_dev->masklength,
> - compound_mask);
> + compound_mask,
> + strict_scanmask);
> kfree(compound_mask);
> if (scan_mask == NULL)
> return -EINVAL;
>
--
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