ASoC: imx-pcm: Request DMA channel early

Request the DMA channel in the pcm open callback. This allows us to let open
fail if there is no dma channel available.

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

1 files changed, 32 insertions, 46 deletions

diff --git a/sound/soc/imx/imx-pcm-dma-mx2.c b/sound/soc/imx/imx-pcm-dma-mx2.c
index ec1394415526..f974e61fa68c 100644
--- a/sound/soc/imx/imx-pcm-dma-mx2.c
+++ b/sound/soc/imx/imx-pcm-dma-mx2.c
@@ -65,17 +65,13 @@ static bool filter(struct dma_chan *chan, void *param)
         return true;
 }
 
-static int imx_ssi_dma_alloc(struct snd_pcm_substream *substream,
-                                struct snd_pcm_hw_params *params)
+static int imx_ssi_dma_alloc(struct snd_pcm_substream *substream)
 {
         struct snd_soc_pcm_runtime *rtd = substream->private_data;
         struct imx_pcm_dma_params *dma_params;
         struct snd_pcm_runtime *runtime = substream->runtime;
         struct imx_pcm_runtime_data *iprtd = runtime->private_data;
-        struct dma_slave_config slave_config;
         dma_cap_mask_t mask;
-        enum dma_slave_buswidth buswidth;
-        int ret;
 
         dma_params = snd_soc_dai_get_dma_data(rtd->cpu_dai, substream);
 
@@ -84,13 +80,29 @@ static int imx_ssi_dma_alloc(struct snd_pcm_substream *substream,
         iprtd->dma_data.dma_request = dma_params->dma;
 
         /* Try to grab a DMA channel */
-        if (!iprtd->dma_chan) {
-                dma_cap_zero(mask);
-                dma_cap_set(DMA_SLAVE, mask);
-                iprtd->dma_chan = dma_request_channel(mask, filter, iprtd);
-                if (!iprtd->dma_chan)
-                        return -EINVAL;
-        }
+        dma_cap_zero(mask);
+        dma_cap_set(DMA_SLAVE, mask);
+        iprtd->dma_chan = dma_request_channel(mask, filter, iprtd);
+        if (!iprtd->dma_chan)
+                return -EINVAL;
+
+        return 0;
+}
+
+static int snd_imx_pcm_hw_params(struct snd_pcm_substream *substream,
+                                struct snd_pcm_hw_params *params)
+{
+        struct snd_soc_pcm_runtime *rtd = substream->private_data;
+        struct snd_pcm_runtime *runtime = substream->runtime;
+        struct imx_pcm_runtime_data *iprtd = runtime->private_data;
+        struct dma_chan *chan = iprtd->dma_chan;
+        struct imx_pcm_dma_params *dma_params;
+        struct dma_slave_config slave_config;
+        enum dma_slave_buswidth buswidth;
+        unsigned long dma_addr;
+        int ret;
+
+        dma_params = snd_soc_dai_get_dma_data(rtd->cpu_dai, substream);
 
         switch (params_format(params)) {
         case SNDRV_PCM_FORMAT_S16_LE:
@@ -116,29 +128,10 @@ static int imx_ssi_dma_alloc(struct snd_pcm_substream *substream,
                 slave_config.src_maxburst = dma_params->burstsize;
         }
 
-        ret = dmaengine_slave_config(iprtd->dma_chan, &slave_config);
+        ret = dmaengine_slave_config(chan, &slave_config);
         if (ret)
                 return ret;
 
-        return 0;
-}
-
-static int snd_imx_pcm_hw_params(struct snd_pcm_substream *substream,
-                                struct snd_pcm_hw_params *params)
-{
-        struct snd_soc_pcm_runtime *rtd = substream->private_data;
-        struct snd_pcm_runtime *runtime = substream->runtime;
-        struct imx_pcm_runtime_data *iprtd = runtime->private_data;
-        unsigned long dma_addr;
-        struct dma_chan *chan;
-        struct imx_pcm_dma_params *dma_params;
-        int ret;
-
-        dma_params = snd_soc_dai_get_dma_data(rtd->cpu_dai, substream);
-        ret = imx_ssi_dma_alloc(substream, params);
-        if (ret)
-                return ret;
-        chan = iprtd->dma_chan;
 
         iprtd->periods = params_periods(params);
         iprtd->period_bytes = params_period_bytes(params);
@@ -164,19 +157,6 @@ static int snd_imx_pcm_hw_params(struct snd_pcm_substream *substream,
         return 0;
 }
 
-static int snd_imx_pcm_hw_free(struct snd_pcm_substream *substream)
-{
-        struct snd_pcm_runtime *runtime = substream->runtime;
-        struct imx_pcm_runtime_data *iprtd = runtime->private_data;
-
-        if (iprtd->dma_chan) {
-                dma_release_channel(iprtd->dma_chan);
-                iprtd->dma_chan = NULL;
-        }
-
-        return 0;
-}
-
 static int snd_imx_pcm_trigger(struct snd_pcm_substream *substream, int cmd)
 {
         struct snd_pcm_runtime *runtime = substream->runtime;
@@ -251,6 +231,12 @@ static int snd_imx_open(struct snd_pcm_substream *substream)
                 return ret;
         }
 
+        ret = imx_ssi_dma_alloc(substream);
+        if (ret < 0) {
+                kfree(iprtd);
+                return ret;
+        }
+
         snd_soc_set_runtime_hwparams(substream, &snd_imx_hardware);
 
         return 0;
@@ -261,6 +247,7 @@ static int snd_imx_close(struct snd_pcm_substream *substream)
         struct snd_pcm_runtime *runtime = substream->runtime;
         struct imx_pcm_runtime_data *iprtd = runtime->private_data;
 
+        dma_release_channel(iprtd->dma_chan);
         kfree(iprtd);
 
         return 0;
@@ -271,7 +258,6 @@ static struct snd_pcm_ops imx_pcm_ops = {
         .close          = snd_imx_close,
         .ioctl          = snd_pcm_lib_ioctl,
         .hw_params      = snd_imx_pcm_hw_params,
-        .hw_free        = snd_imx_pcm_hw_free,
         .trigger        = snd_imx_pcm_trigger,
         .pointer        = snd_imx_pcm_pointer,
         .mmap           = snd_imx_pcm_mmap,