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

Maxime Ripard
2014-10-22T15:45:25Z

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>
---
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);
--
2.1.1