Re: [PATCH v3 05/59] dmaengine: Make channel allocation callbacks optional

Laurent Pinchart
2014-10-22T21:05:18Z

Hi Maxime,

Thank you for the patch.

On Wednesday 22 October 2014 17:43:19 Maxime Ripard wrote:
> Nowadays, some drivers don't have anything in there channel allocation
> callbacks anymore.
>
> Remove the BUG_ON if those callbacks aren't implemented, in order to allow
> drivers to not implement them.
>
> Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>

Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

> ---
> drivers/dma/dmaengine.c | 18 +++++++++++-------
> 1 file changed, 11 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/dma/dmaengine.c b/drivers/dma/dmaengine.c
> index 72f10e2f5c32..9b2cd74b8f2e 100644
> --- a/drivers/dma/dmaengine.c
> +++ b/drivers/dma/dmaengine.c
> @@ -235,9 +235,11 @@ static int dma_chan_get(struct dma_chan *chan)
> return -ENODEV;
>
> /* allocate upon first client reference */
> - ret = chan->device->device_alloc_chan_resources(chan);
> - if (ret < 0)
> - goto err_out;
> + if (chan->device->device_alloc_chan_resources) {
> + ret = chan->device->device_alloc_chan_resources(chan);
> + if (ret < 0)
> + goto err_out;
> + }
>
> if (!dma_has_cap(DMA_PRIVATE, chan->device->cap_mask))
> balance_ref_count(chan);
> @@ -259,11 +261,15 @@ err_out:
> */
> static void dma_chan_put(struct dma_chan *chan)
> {
> + /* This channel is not in use, bail out */
> if (!chan->client_count)
> - return; /* this channel failed alloc_chan_resources */
> + return;
> +
> chan->client_count--;
> module_put(dma_chan_to_owner(chan));
> - if (chan->client_count == 0)
> +
> + /* This channel is not in use anymore, free it */
> + if (!chan->client_count && chan->device->device_free_chan_resources)
> chan->device->device_free_chan_resources(chan);
> }
>
> @@ -819,8 +825,6 @@ int dma_async_device_register(struct dma_device *device)
> BUG_ON(dma_has_cap(DMA_INTERLEAVE, device->cap_mask) &&
> !device->device_prep_interleaved_dma);
>
> - BUG_ON(!device->device_alloc_chan_resources);
> - BUG_ON(!device->device_free_chan_resources);
> BUG_ON(!device->device_tx_status);
> BUG_ON(!device->device_issue_pending);
> BUG_ON(!device->dev);

--
Regards,

Laurent Pinchart