diff options
Diffstat (limited to 'drivers/dma/dmaengine.c')
| -rw-r--r-- | drivers/dma/dmaengine.c | 26 |
1 files changed, 26 insertions, 0 deletions
diff --git a/drivers/dma/dmaengine.c b/drivers/dma/dmaengine.c index 93f7992bee5c..78dbbe09d7b1 100644 --- a/drivers/dma/dmaengine.c +++ b/drivers/dma/dmaengine.c @@ -504,6 +504,32 @@ static struct dma_chan *private_candidate(const dma_cap_mask_t *mask, } /** + * dma_request_channel - try to get specific channel exclusively + * @chan: target channel + */ +struct dma_chan *dma_get_slave_channel(struct dma_chan *chan) +{ + int err = -EBUSY; + + /* lock against __dma_request_channel */ + mutex_lock(&dma_list_mutex); + + if (chan->client_count == 0) + err = dma_chan_get(chan); + else + chan = NULL; + + mutex_unlock(&dma_list_mutex); + + if (err) + pr_debug("%s: failed to get %s: (%d)\n", + __func__, dma_chan_name(chan), err); + + return chan; +} +EXPORT_SYMBOL_GPL(dma_get_slave_channel); + +/** * dma_request_channel - try to allocate an exclusive channel * @mask: capabilities that the channel must satisfy * @fn: optional callback to disposition available channels |