From: Stephen Warren swarren@nvidia.com

Enhance dmaengine_pcm_request_chan_of() to support deferred probe for DMA channels, by using the new dma_request_slave_channel_or_err() API. This prevents snd_dmaengine_pcm_register() from succeeding without acquiring DMA channels due to the relevant DMA controller not yet being registered.

Signed-off-by: Stephen Warren swarren@nvidia.com Acked-by: Lars-Peter Clausen lars@metafoo.de --- Mark, this is the patch which requires the dependency from the DMA tree, i.e. what I mentioned in the pull request that I sent just a little while ago. You'd previously ack'd it so I could take it through the Tegra tree, but it's probably better if instead you put it into ASoC tree first, then I pull your (topic/dma?) branch into the Tegra tree.

(I've validated that your current topic/dma, plus a merge of the DMA tree's topic/defer_probe, plus this patch, plus a merge of next-20131210 to pick up the rest of ASoC etc., runs without conflicts and builds at least for Tegra without issues).

v3: * Fix missing braces around else block. v2: * Call dmaengine_pcm_release_chan() if dmaengine_pcm_request_chan_of() fails, to clean up any partial allocations. --- sound/soc/soc-generic-dmaengine-pcm.c | 20 ++++++++++++++++---- 1 file changed, 16 insertions(+), 4 deletions(-)

diff --git a/sound/soc/soc-generic-dmaengine-pcm.c b/sound/soc/soc-generic-dmaengine-pcm.c index 5b70c556fba3..585eaa69e8c3 100644 --- a/sound/soc/soc-generic-dmaengine-pcm.c +++ b/sound/soc/soc-generic-dmaengine-pcm.c @@ -287,16 +287,17 @@ static const char * const dmaengine_pcm_dma_channel_names[] = { [SNDRV_PCM_STREAM_CAPTURE] = "rx", };

-static void dmaengine_pcm_request_chan_of(struct dmaengine_pcm *pcm, +static int dmaengine_pcm_request_chan_of(struct dmaengine_pcm *pcm, struct device *dev, const struct snd_dmaengine_pcm_config *config) { unsigned int i; const char *name; + struct dma_chan *chan;

if ((pcm->flags & (SND_DMAENGINE_PCM_FLAG_NO_DT | SND_DMAENGINE_PCM_FLAG_CUSTOM_CHANNEL_NAME)) || !dev->of_node) - return; + return 0;

if (config->dma_dev) { /* @@ -318,13 +319,22 @@ static void dmaengine_pcm_request_chan_of(struct dmaengine_pcm *pcm, name = dmaengine_pcm_dma_channel_names[i]; if (config->chan_names[i]) name = config->chan_names[i]; - pcm->chan[i] = dma_request_slave_channel(dev, name); + chan = dma_request_slave_channel_reason(dev, name); + if (IS_ERR(chan)) { + if (PTR_ERR(pcm->chan[i]) == -EPROBE_DEFER) + return -EPROBE_DEFER; + pcm->chan[i] = NULL; + } else { + pcm->chan[i] = chan; + } if (pcm->flags & SND_DMAENGINE_PCM_FLAG_HALF_DUPLEX) break; }

if (pcm->flags & SND_DMAENGINE_PCM_FLAG_HALF_DUPLEX) pcm->chan[1] = pcm->chan[0]; + + return 0; }

static void dmaengine_pcm_release_chan(struct dmaengine_pcm *pcm) @@ -360,7 +370,9 @@ int snd_dmaengine_pcm_register(struct device *dev, pcm->config = config; pcm->flags = flags;

- dmaengine_pcm_request_chan_of(pcm, dev, config); + ret = dmaengine_pcm_request_chan_of(pcm, dev, config); + if (ret) + goto err_free_dma;

if (flags & SND_DMAENGINE_PCM_FLAG_NO_RESIDUE) ret = snd_soc_add_platform(dev, &pcm->platform,