From: Stephen Warren <swarren@xxxxxxxxxx>
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.
Cc: treding@xxxxxxxxxx
Cc: linux-tegra@xxxxxxxxxxxxxxx
Cc: linux-arm-kernel@xxxxxxxxxxxxxxxxxxx
Cc: Liam Girdwood <lgirdwood@xxxxxxxxx>
Cc: Mark Brown <broonie@xxxxxxxxxx>
Cc: alsa-devel@xxxxxxxxxxxxxxxx
Signed-off-by: Stephen Warren <swarren@xxxxxxxxxx>
---
This patch is part of a series with strong internal depdendencies. I'm
looking for an ack so that I can take the entire series through the Tegra
and arm-soc trees. The series will be part of a stable branch that can be
merged into other subsystems if needed to avoid/resolve dependencies.
---
sound/soc/soc-generic-dmaengine-pcm.c | 77 +++++++++++++++++++++++++----------
1 file changed, 55 insertions(+), 22 deletions(-)
diff --git a/sound/soc/soc-generic-dmaengine-pcm.c b/sound/soc/soc-generic-dmaengine-pcm.c
index cbc9c96ce1f4..f7e65e1552ef 100644
--- a/sound/soc/soc-generic-dmaengine-pcm.c
+++ b/sound/soc/soc-generic-dmaengine-pcm.c
@@ -284,24 +284,52 @@ 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,
- struct device *dev)
+static int dmaengine_pcm_request_chan_of(struct dmaengine_pcm *pcm,
+ struct device *dev)
{
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;
+
+ for (i = SNDRV_PCM_STREAM_PLAYBACK; i <= SNDRV_PCM_STREAM_CAPTURE;
+ i++) {
+ if (pcm->flags & SND_DMAENGINE_PCM_FLAG_HALF_DUPLEX)
+ name = "rx-tx";
+ else
+ name = dmaengine_pcm_dma_channel_names[i];
+ chan = dma_request_slave_channel_or_err(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[0] = dma_request_slave_channel(dev, "rx-tx");
+ if (pcm->flags & SND_DMAENGINE_PCM_FLAG_HALF_DUPLEX)
pcm->chan[1] = pcm->chan[0];
- } else {
- for (i = SNDRV_PCM_STREAM_PLAYBACK; i <= SNDRV_PCM_STREAM_CAPTURE; i++) {
- pcm->chan[i] = dma_request_slave_channel(dev,
- dmaengine_pcm_dma_channel_names[i]);
- }
+
+ return 0;
+}
+
+static void dmaengine_pcm_release_chan(struct dmaengine_pcm *pcm)
+{
+ unsigned int i;
+
+ for (i = SNDRV_PCM_STREAM_PLAYBACK; i <= SNDRV_PCM_STREAM_CAPTURE;
+ i++) {
+ if (!pcm->chan[i])
+ continue;
+ dma_release_channel(pcm->chan[i]);
+ if (pcm->flags & SND_DMAENGINE_PCM_FLAG_HALF_DUPLEX)
+ break;
}
}
@@ -315,6 +343,7 @@ int snd_dmaengine_pcm_register(struct device *dev,
const struct snd_dmaengine_pcm_config *config, unsigned int flags)
{
struct dmaengine_pcm *pcm;
+ int ret;
pcm = kzalloc(sizeof(*pcm), GFP_KERNEL);
if (!pcm)
@@ -323,14 +352,26 @@ int snd_dmaengine_pcm_register(struct device *dev,
pcm->config = config;
pcm->flags = flags;
- dmaengine_pcm_request_chan_of(pcm, dev);
+ ret = dmaengine_pcm_request_chan_of(pcm, dev);
+ if (ret)
+ goto err_free_pcm;
if (flags & SND_DMAENGINE_PCM_FLAG_NO_RESIDUE)
- return snd_soc_add_platform(dev, &pcm->platform,
+ ret = snd_soc_add_platform(dev, &pcm->platform,
&dmaengine_no_residue_pcm_platform);
else
- return snd_soc_add_platform(dev, &pcm->platform,
+ ret = snd_soc_add_platform(dev, &pcm->platform,
&dmaengine_pcm_platform);
+ if (ret)
+ goto err_free_dma;
+
+ return 0;
+
+err_free_dma:
+ dmaengine_pcm_release_chan(pcm);
+err_free_pcm:
+ kfree(pcm);
+ return ret;
}
EXPORT_SYMBOL_GPL(snd_dmaengine_pcm_register);
@@ -345,7 +386,6 @@ void snd_dmaengine_pcm_unregister(struct device *dev)
{
struct snd_soc_platform *platform;
struct dmaengine_pcm *pcm;
- unsigned int i;
platform = snd_soc_lookup_platform(dev);
if (!platform)
@@ -353,15 +393,8 @@ void snd_dmaengine_pcm_unregister(struct device *dev)
pcm = soc_platform_to_pcm(platform);
- for (i = SNDRV_PCM_STREAM_PLAYBACK; i <= SNDRV_PCM_STREAM_CAPTURE; i++) {
- if (pcm->chan[i]) {
- dma_release_channel(pcm->chan[i]);
- if (pcm->flags & SND_DMAENGINE_PCM_FLAG_HALF_DUPLEX)
- break;
- }
- }
-
snd_soc_remove_platform(platform);
+ dmaengine_pcm_release_chan(pcm);
kfree(pcm);
}
EXPORT_SYMBOL_GPL(snd_dmaengine_pcm_unregister);
--
1.8.1.5
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