ASoC: dmaengine-pcm: Make requesting the DMA channel at PCM open optional

Refactor the dmaengine PCM library to allow the DMA channel to be requested
before opening a PCM substream. snd_dmaengine_pcm_open() now expects a DMA
channel instead of a filter function and filter parameter as its parameters.
snd_dmaengine_pcm_close() is updated to not release the DMA channel. This allows
a dmaengine based PCM driver to request its channels before the substream is
opened.

The patch also introduces two new functions, snd_dmaengine_pcm_open_request_chan()
and snd_dmaengine_pcm_close_release_chan(), which have the same signature and
behaviour of the old snd_dmaengine_pcm_{open,close}() and internally use the new
variants of these functions. All users of snd_dmaengine_pcm_{open,close}() are
updated to use snd_dmaengine_pcm_open_request_chan() and
snd_dmaengine_pcm_close_release_chan().

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Tested-by: Stephen Warren <swarren@nvidia.com>
Tested-by: Shawn Guo <shawn.guo@linaro.org>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

10 files changed, 73 insertions, 43 deletions

diff --git a/sound/soc/atmel/atmel-pcm-dma.c b/sound/soc/atmel/atmel-pcm-dma.c
index bb07989762d5..1d38fd0bc4e2 100644
--- a/sound/soc/atmel/atmel-pcm-dma.c
+++ b/sound/soc/atmel/atmel-pcm-dma.c
@@ -155,7 +155,7 @@ static int atmel_pcm_hw_params(struct snd_pcm_substream *substream,
         if (ssc->pdev)
                 sdata = ssc->pdev->dev.platform_data;
 
-        ret = snd_dmaengine_pcm_open(substream, filter, sdata);
+        ret = snd_dmaengine_pcm_open_request_chan(substream, filter, sdata);
         if (ret) {
                 pr_err("atmel-pcm: dmaengine pcm open failed\n");
                 return -EINVAL;
@@ -171,7 +171,7 @@ static int atmel_pcm_hw_params(struct snd_pcm_substream *substream,
 
         return 0;
 err:
-        snd_dmaengine_pcm_close(substream);
+        snd_dmaengine_pcm_close_release_chan(substream);
         return ret;
 }
 
@@ -197,7 +197,7 @@ static int atmel_pcm_open(struct snd_pcm_substream *substream)
 
 static struct snd_pcm_ops atmel_pcm_ops = {
         .open           = atmel_pcm_open,
-        .close          = snd_dmaengine_pcm_close,
+        .close          = snd_dmaengine_pcm_close_release_chan,
         .ioctl          = snd_pcm_lib_ioctl,
         .hw_params      = atmel_pcm_hw_params,
         .prepare        = atmel_pcm_dma_prepare,
diff --git a/sound/soc/cirrus/ep93xx-pcm.c b/sound/soc/cirrus/ep93xx-pcm.c
index 298946f790eb..488032690378 100644
--- a/sound/soc/cirrus/ep93xx-pcm.c
+++ b/sound/soc/cirrus/ep93xx-pcm.c
@@ -69,7 +69,8 @@ static int ep93xx_pcm_open(struct snd_pcm_substream *substream)
 
         snd_soc_set_runtime_hwparams(substream, &ep93xx_pcm_hardware);
 
-        return snd_dmaengine_pcm_open(substream, ep93xx_pcm_dma_filter,
+        return snd_dmaengine_pcm_open_request_chan(substream,
+                        ep93xx_pcm_dma_filter,
                         snd_soc_dai_get_dma_data(rtd->cpu_dai, substream));
 }
 
@@ -100,7 +101,7 @@ static int ep93xx_pcm_mmap(struct snd_pcm_substream *substream,
 
 static struct snd_pcm_ops ep93xx_pcm_ops = {
         .open           = ep93xx_pcm_open,
-        .close          = snd_dmaengine_pcm_close,
+        .close          = snd_dmaengine_pcm_close_release_chan,
         .ioctl          = snd_pcm_lib_ioctl,
         .hw_params      = ep93xx_pcm_hw_params,
         .hw_free        = ep93xx_pcm_hw_free,
diff --git a/sound/soc/fsl/imx-pcm-dma.c b/sound/soc/fsl/imx-pcm-dma.c
index ee838c8a3b11..c6647825bdd5 100644
--- a/sound/soc/fsl/imx-pcm-dma.c
+++ b/sound/soc/fsl/imx-pcm-dma.c
@@ -100,7 +100,7 @@ static int snd_imx_open(struct snd_pcm_substream *substream)
 
 static struct snd_pcm_ops imx_pcm_ops = {
         .open           = snd_imx_open,
-        .close          = snd_dmaengine_pcm_close,
+        .close          = snd_dmaengine_pcm_close_release_chan,
         .ioctl          = snd_pcm_lib_ioctl,
         .hw_params      = snd_imx_pcm_hw_params,
         .trigger        = snd_dmaengine_pcm_trigger,
diff --git a/sound/soc/mxs/mxs-pcm.c b/sound/soc/mxs/mxs-pcm.c
index ebbef8597554..7bceb16d0fd9 100644
--- a/sound/soc/mxs/mxs-pcm.c
+++ b/sound/soc/mxs/mxs-pcm.c
@@ -87,7 +87,7 @@ static int snd_mxs_open(struct snd_pcm_substream *substream)
 
         snd_soc_set_runtime_hwparams(substream, &snd_mxs_hardware);
 
-        return snd_dmaengine_pcm_open(substream, filter,
+        return snd_dmaengine_pcm_open_request_chan(substream, filter,
                 snd_soc_dai_get_dma_data(rtd->cpu_dai, substream));
 }
 
@@ -104,7 +104,7 @@ static int snd_mxs_pcm_mmap(struct snd_pcm_substream *substream,
 
 static struct snd_pcm_ops mxs_pcm_ops = {
         .open           = snd_mxs_open,
-        .close          = snd_dmaengine_pcm_close,
+        .close          = snd_dmaengine_pcm_close_release_chan,
         .ioctl          = snd_pcm_lib_ioctl,
         .hw_params      = snd_mxs_pcm_hw_params,
         .trigger        = snd_dmaengine_pcm_trigger,
diff --git a/sound/soc/omap/omap-pcm.c b/sound/soc/omap/omap-pcm.c
index c8e272f9c2de..c28e042f2208 100644
--- a/sound/soc/omap/omap-pcm.c
+++ b/sound/soc/omap/omap-pcm.c
@@ -118,8 +118,9 @@ static int omap_pcm_open(struct snd_pcm_substream *substream)
 
         dma_data = snd_soc_dai_get_dma_data(rtd->cpu_dai, substream);
 
-        return snd_dmaengine_pcm_open(substream, omap_dma_filter_fn,
-                                      dma_data->filter_data);
+        return snd_dmaengine_pcm_open_request_chan(substream,
+                                                   omap_dma_filter_fn,
+                                                   dma_data->filter_data);
 }
 
 static int omap_pcm_mmap(struct snd_pcm_substream *substream,
@@ -135,7 +136,7 @@ static int omap_pcm_mmap(struct snd_pcm_substream *substream,
 
 static struct snd_pcm_ops omap_pcm_ops = {
         .open           = omap_pcm_open,
-        .close          = snd_dmaengine_pcm_close,
+        .close          = snd_dmaengine_pcm_close_release_chan,
         .ioctl          = snd_pcm_lib_ioctl,
         .hw_params      = omap_pcm_hw_params,
         .hw_free        = omap_pcm_hw_free,
diff --git a/sound/soc/pxa/mmp-pcm.c b/sound/soc/pxa/mmp-pcm.c
index 6c3980252bf6..349930015264 100644
--- a/sound/soc/pxa/mmp-pcm.c
+++ b/sound/soc/pxa/mmp-pcm.c
@@ -131,7 +131,8 @@ static int mmp_pcm_open(struct snd_pcm_substream *substream)
         dma_data.dma_res = r;
         dma_data.ssp_id = cpu_dai->id;
 
-        return snd_dmaengine_pcm_open(substream, filter, &dma_data);
+        return snd_dmaengine_pcm_open_request_chan(substream, filter,
+                    &dma_data);
 }
 
 static int mmp_pcm_mmap(struct snd_pcm_substream *substream,
@@ -148,7 +149,7 @@ static int mmp_pcm_mmap(struct snd_pcm_substream *substream,
 
 struct snd_pcm_ops mmp_pcm_ops = {
         .open           = mmp_pcm_open,
-        .close          = snd_dmaengine_pcm_close,
+        .close          = snd_dmaengine_pcm_close_release_chan,
         .ioctl          = snd_pcm_lib_ioctl,
         .hw_params      = mmp_pcm_hw_params,
         .trigger        = snd_dmaengine_pcm_trigger,
diff --git a/sound/soc/soc-dmaengine-pcm.c b/sound/soc/soc-dmaengine-pcm.c
index a9a300acb506..b0420a75f412 100644
--- a/sound/soc/soc-dmaengine-pcm.c
+++ b/sound/soc/soc-dmaengine-pcm.c
@@ -254,44 +254,38 @@ snd_pcm_uframes_t snd_dmaengine_pcm_pointer(struct snd_pcm_substream *substream)
 }
 EXPORT_SYMBOL_GPL(snd_dmaengine_pcm_pointer);
 
-static int dmaengine_pcm_request_channel(struct dmaengine_pcm_runtime_data *prtd,
-        dma_filter_fn filter_fn, void *filter_data)
+static struct dma_chan *dmaengine_pcm_request_channel(dma_filter_fn filter_fn,
+        void *filter_data)
 {
         dma_cap_mask_t mask;
 
         dma_cap_zero(mask);
         dma_cap_set(DMA_SLAVE, mask);
         dma_cap_set(DMA_CYCLIC, mask);
-        prtd->dma_chan = dma_request_channel(mask, filter_fn, filter_data);
-
-        if (!prtd->dma_chan)
-                return -ENXIO;
 
-        return 0;
+        return dma_request_channel(mask, filter_fn, filter_data);
 }
 
 /**
  * snd_dmaengine_pcm_open - Open a dmaengine based PCM substream
  * @substream: PCM substream
- * @filter_fn: Filter function used to request the DMA channel
- * @filter_data: Data passed to the DMA filter function
+ * @chan: DMA channel to use for data transfers
  *
  * Returns 0 on success, a negative error code otherwise.
  *
- * This function will request a DMA channel using the passed filter function and
- * data. The function should usually be called from the pcm open callback.
- *
- * Note that this function will use private_data field of the substream's
- * runtime. So it is not availabe to your pcm driver implementation. If you need
- * to keep additional data attached to a substream use
- * snd_dmaengine_pcm_{set,get}_data.
+ * The function should usually be called from the pcm open callback. Note that
+ * this function will use private_data field of the substream's runtime. So it
+ * is not availabe to your pcm driver implementation.
  */
 int snd_dmaengine_pcm_open(struct snd_pcm_substream *substream,
-        dma_filter_fn filter_fn, void *filter_data)
+        struct dma_chan *chan)
 {
         struct dmaengine_pcm_runtime_data *prtd;
         int ret;
 
+        if (!chan)
+                return -ENXIO;
+
         ret = snd_pcm_hw_constraint_integer(substream->runtime,
                                             SNDRV_PCM_HW_PARAM_PERIODS);
         if (ret < 0)
@@ -301,11 +295,7 @@ int snd_dmaengine_pcm_open(struct snd_pcm_substream *substream,
         if (!prtd)
                 return -ENOMEM;
 
-        ret = dmaengine_pcm_request_channel(prtd, filter_fn, filter_data);
-        if (ret < 0) {
-                kfree(prtd);
-                return ret;
-        }
+        prtd->dma_chan = chan;
 
         substream->runtime->private_data = prtd;
 
@@ -314,6 +304,27 @@ int snd_dmaengine_pcm_open(struct snd_pcm_substream *substream,
 EXPORT_SYMBOL_GPL(snd_dmaengine_pcm_open);
 
 /**
+ * snd_dmaengine_pcm_open_request_chan - Open a dmaengine based PCM substream and request channel
+ * @substream: PCM substream
+ * @filter_fn: Filter function used to request the DMA channel
+ * @filter_data: Data passed to the DMA filter function
+ *
+ * Returns 0 on success, a negative error code otherwise.
+ *
+ * This function will request a DMA channel using the passed filter function and
+ * data. The function should usually be called from the pcm open callback. Note
+ * that this function will use private_data field of the substream's runtime. So
+ * it is not availabe to your pcm driver implementation.
+ */
+int snd_dmaengine_pcm_open_request_chan(struct snd_pcm_substream *substream,
+        dma_filter_fn filter_fn, void *filter_data)
+{
+        return snd_dmaengine_pcm_open(substream,
+                    dmaengine_pcm_request_channel(filter_fn, filter_data));
+}
+EXPORT_SYMBOL_GPL(snd_dmaengine_pcm_open_request_chan);
+
+/**
  * snd_dmaengine_pcm_close - Close a dmaengine based PCM substream
  * @substream: PCM substream
  */
@@ -321,11 +332,26 @@ int snd_dmaengine_pcm_close(struct snd_pcm_substream *substream)
 {
         struct dmaengine_pcm_runtime_data *prtd = substream_to_prtd(substream);
 
-        dma_release_channel(prtd->dma_chan);
         kfree(prtd);
 
         return 0;
 }
 EXPORT_SYMBOL_GPL(snd_dmaengine_pcm_close);
 
+/**
+ * snd_dmaengine_pcm_release_chan_close - Close a dmaengine based PCM substream and release channel
+ * @substream: PCM substream
+ *
+ * Releases the DMA channel associated with the PCM substream.
+ */
+int snd_dmaengine_pcm_close_release_chan(struct snd_pcm_substream *substream)
+{
+        struct dmaengine_pcm_runtime_data *prtd = substream_to_prtd(substream);
+
+        dma_release_channel(prtd->dma_chan);
+
+        return snd_dmaengine_pcm_close(substream);
+}
+EXPORT_SYMBOL_GPL(snd_dmaengine_pcm_close_release_chan);
+
 MODULE_LICENSE("GPL");
diff --git a/sound/soc/spear/spear_pcm.c b/sound/soc/spear/spear_pcm.c
index db75d72c4805..ba66a3f370a3 100644
--- a/sound/soc/spear/spear_pcm.c
+++ b/sound/soc/spear/spear_pcm.c
@@ -64,7 +64,8 @@ static int spear_pcm_open(struct snd_pcm_substream *substream)
         if (ret)
                 return ret;
 
-        return snd_dmaengine_pcm_open(substream, dma_data->filter, dma_data)
+        return snd_dmaengine_pcm_open_request_chan(substream, dma_data->filter,
+                                dma_data);
 }
 
 static int spear_pcm_mmap(struct snd_pcm_substream *substream,
@@ -79,7 +80,7 @@ static int spear_pcm_mmap(struct snd_pcm_substream *substream,
 
 static struct snd_pcm_ops spear_pcm_ops = {
         .open           = spear_pcm_open,
-        .close          = snd_dmaengine_pcm_close,
+        .close          = snd_dmaengine_pcm_close_release_chan,
         .ioctl          = snd_pcm_lib_ioctl,
         .hw_params      = spear_pcm_hw_params,
         .hw_free        = spear_pcm_hw_free,
diff --git a/sound/soc/tegra/tegra_pcm.c b/sound/soc/tegra/tegra_pcm.c
index f91d08bc1753..32d08119dd87 100644
--- a/sound/soc/tegra/tegra_pcm.c
+++ b/sound/soc/tegra/tegra_pcm.c
@@ -66,7 +66,7 @@ static int tegra_pcm_open(struct snd_pcm_substream *substream)
         /* Set HW params now that initialization is complete */
         snd_soc_set_runtime_hwparams(substream, &tegra_pcm_hardware);
 
-        ret = snd_dmaengine_pcm_open(substream, NULL, NULL);
+        ret = snd_dmaengine_pcm_open_request_chan(substream, NULL, NULL);
         if (ret) {
                 dev_err(dev, "dmaengine pcm open failed with err %d\n", ret);
                 return ret;
@@ -144,7 +144,7 @@ static int tegra_pcm_mmap(struct snd_pcm_substream *substream,
 
 static struct snd_pcm_ops tegra_pcm_ops = {
         .open           = tegra_pcm_open,
-        .close          = snd_dmaengine_pcm_close,
+        .close          = snd_dmaengine_pcm_close_release_chan,
         .ioctl          = snd_pcm_lib_ioctl,
         .hw_params      = tegra_pcm_hw_params,
         .hw_free        = tegra_pcm_hw_free,
diff --git a/sound/soc/ux500/ux500_pcm.c b/sound/soc/ux500/ux500_pcm.c
index 09b5364e5095..a7d4f04e5964 100644
--- a/sound/soc/ux500/ux500_pcm.c
+++ b/sound/soc/ux500/ux500_pcm.c
@@ -125,8 +125,8 @@ static int ux500_pcm_open(struct snd_pcm_substream *substream)
                 dma_cfg->dst_info.data_width = mem_data_width;
         }
 
-
-        ret = snd_dmaengine_pcm_open(substream, stedma40_filter, dma_cfg);
+        ret = snd_dmaengine_pcm_open_request_chan(substream, stedma40_filter,
+                        dma_cfg);
         if (ret) {
                 dev_dbg(dai->dev,
                         "%s: ERROR: snd_dmaengine_pcm_open failed (%d)!\n",
@@ -211,7 +211,7 @@ static int ux500_pcm_mmap(struct snd_pcm_substream *substream,
 
 static struct snd_pcm_ops ux500_pcm_ops = {
         .open           = ux500_pcm_open,
-        .close          = snd_dmaengine_pcm_close,
+        .close          = snd_dmaengine_pcm_close_release_chan,
         .ioctl          = snd_pcm_lib_ioctl,
         .hw_params      = ux500_pcm_hw_params,
         .hw_free        = ux500_pcm_hw_free,