3 files changed, 55 insertions, 25 deletions

diff --git a/include/sound/dmaengine_pcm.h b/include/sound/dmaengine_pcm.h
index f86ef5ea9b01..67be2445941a 100644
--- a/include/sound/dmaengine_pcm.h
+++ b/include/sound/dmaengine_pcm.h
@@ -51,6 +51,16 @@ struct dma_chan *snd_dmaengine_pcm_request_channel(dma_filter_fn filter_fn,
         void *filter_data);
 struct dma_chan *snd_dmaengine_pcm_get_chan(struct snd_pcm_substream *substream);
 
+/*
+ * The DAI supports packed transfers, eg 2 16-bit samples in a 32-bit word.
+ * If this flag is set the dmaengine driver won't put any restriction on
+ * the supported sample formats and set the DMA transfer size to undefined.
+ * The DAI driver is responsible to disable any unsupported formats in it's
+ * configuration and catch corner cases that are not already handled in
+ * the ALSA core.
+ */
+#define SND_DMAENGINE_PCM_DAI_FLAG_PACK BIT(0)
+
 /**
  * struct snd_dmaengine_dai_dma_data - DAI DMA configuration data
  * @addr: Address of the DAI data source or destination register.
@@ -63,6 +73,7 @@ struct dma_chan *snd_dmaengine_pcm_get_chan(struct snd_pcm_substream *substream)
  * requesting the DMA channel.
  * @chan_name: Custom channel name to use when requesting DMA channel.
  * @fifo_size: FIFO size of the DAI controller in bytes
+ * @flags: PCM_DAI flags, only SND_DMAENGINE_PCM_DAI_FLAG_PACK for now
  */
 struct snd_dmaengine_dai_dma_data {
         dma_addr_t addr;
@@ -72,6 +83,7 @@ struct snd_dmaengine_dai_dma_data {
         void *filter_data;
         const char *chan_name;
         unsigned int fifo_size;
+        unsigned int flags;
 };
 
 void snd_dmaengine_pcm_set_config_from_dai_data(
diff --git a/sound/core/pcm_dmaengine.c b/sound/core/pcm_dmaengine.c
index 697c166acf05..8eb58c709b14 100644
--- a/sound/core/pcm_dmaengine.c
+++ b/sound/core/pcm_dmaengine.c
@@ -106,8 +106,9 @@ EXPORT_SYMBOL_GPL(snd_hwparams_to_dma_slave_config);
  * direction of the substream. If the substream is a playback stream the dst
  * fields will be initialized, if it is a capture stream the src fields will be
  * initialized. The {dst,src}_addr_width field will only be initialized if the
- * addr_width field of the DAI DMA data struct is not equal to
- * DMA_SLAVE_BUSWIDTH_UNDEFINED.
+ * SND_DMAENGINE_PCM_DAI_FLAG_PACK flag is set or if the addr_width field of
+ * the DAI DMA data struct is not equal to DMA_SLAVE_BUSWIDTH_UNDEFINED. If
+ * both conditions are met the latter takes priority.
  */
 void snd_dmaengine_pcm_set_config_from_dai_data(
         const struct snd_pcm_substream *substream,
@@ -117,11 +118,17 @@ void snd_dmaengine_pcm_set_config_from_dai_data(
         if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) {
                 slave_config->dst_addr = dma_data->addr;
                 slave_config->dst_maxburst = dma_data->maxburst;
+                if (dma_data->flags & SND_DMAENGINE_PCM_DAI_FLAG_PACK)
+                        slave_config->dst_addr_width =
+                                DMA_SLAVE_BUSWIDTH_UNDEFINED;
                 if (dma_data->addr_width != DMA_SLAVE_BUSWIDTH_UNDEFINED)
                         slave_config->dst_addr_width = dma_data->addr_width;
         } else {
                 slave_config->src_addr = dma_data->addr;
                 slave_config->src_maxburst = dma_data->maxburst;
+                if (dma_data->flags & SND_DMAENGINE_PCM_DAI_FLAG_PACK)
+                        slave_config->src_addr_width =
+                                DMA_SLAVE_BUSWIDTH_UNDEFINED;
                 if (dma_data->addr_width != DMA_SLAVE_BUSWIDTH_UNDEFINED)
                         slave_config->src_addr_width = dma_data->addr_width;
         }
diff --git a/sound/soc/soc-generic-dmaengine-pcm.c b/sound/soc/soc-generic-dmaengine-pcm.c
index 6fd1906af387..6cef3977507a 100644
--- a/sound/soc/soc-generic-dmaengine-pcm.c
+++ b/sound/soc/soc-generic-dmaengine-pcm.c
@@ -163,31 +163,42 @@ static int dmaengine_pcm_set_runtime_hwparams(struct snd_pcm_substream *substrea
         }
 
         /*
-         * Prepare formats mask for valid/allowed sample types. If the dma does
-         * not have support for the given physical word size, it needs to be
-         * masked out so user space can not use the format which produces
-         * corrupted audio.
-         * In case the dma driver does not implement the slave_caps the default
-         * assumption is that it supports 1, 2 and 4 bytes widths.
+         * If SND_DMAENGINE_PCM_DAI_FLAG_PACK is set keep
+         * hw.formats set to 0, meaning no restrictions are in place.
+         * In this case it's the responsibility of the DAI driver to
+         * provide the supported format information.
          */
-        for (i = 0; i <= SNDRV_PCM_FORMAT_LAST; i++) {
-                int bits = snd_pcm_format_physical_width(i);
-
-                /* Enable only samples with DMA supported physical widths */
-                switch (bits) {
-                case 8:
-                case 16:
-                case 24:
-                case 32:
-                case 64:
-                        if (addr_widths & (1 << (bits / 8)))
-                                hw.formats |= (1LL << i);
-                        break;
-                default:
-                        /* Unsupported types */
-                        break;
+        if (!(dma_data->flags & SND_DMAENGINE_PCM_DAI_FLAG_PACK))
+                /*
+                 * Prepare formats mask for valid/allowed sample types. If the
+                 * dma does not have support for the given physical word size,
+                 * it needs to be masked out so user space can not use the
+                 * format which produces corrupted audio.
+                 * In case the dma driver does not implement the slave_caps the
+                 * default assumption is that it supports 1, 2 and 4 bytes
+                 * widths.
+                 */
+                for (i = 0; i <= SNDRV_PCM_FORMAT_LAST; i++) {
+                        int bits = snd_pcm_format_physical_width(i);
+
+                        /*
+                         * Enable only samples with DMA supported physical
+                         * widths
+                         */
+                        switch (bits) {
+                        case 8:
+                        case 16:
+                        case 24:
+                        case 32:
+                        case 64:
+                                if (addr_widths & (1 << (bits / 8)))
+                                        hw.formats |= (1LL << i);
+                                break;
+                        default:
+                                /* Unsupported types */
+                                break;
+                        }
                 }
-        }
 
         return snd_soc_set_runtime_hwparams(substream, &hw);
 }