1 files changed, 83 insertions, 0 deletions
diff --git a/sound/core/pcm_dmaengine.c b/sound/core/pcm_dmaengine.c
index 89a05926ac73..5749a8a49784 100644
--- a/sound/core/pcm_dmaengine.c
+++ b/sound/core/pcm_dmaengine.c
@@ -369,4 +369,87 @@ int snd_dmaengine_pcm_close_release_chan(struct snd_pcm_substream *substream)
 }
 EXPORT_SYMBOL_GPL(snd_dmaengine_pcm_close_release_chan);
 
+/**
+ * snd_dmaengine_pcm_refine_runtime_hwparams - Refine runtime hw params
+ * @substream: PCM substream
+ * @dma_data: DAI DMA data
+ * @hw: PCM hw params
+ * @chan: DMA channel to use for data transfers
+ *
+ * Returns 0 on success, a negative error code otherwise.
+ *
+ * This function will query DMA capability, then refine the pcm hardware
+ * parameters.
+ */
+int snd_dmaengine_pcm_refine_runtime_hwparams(
+	struct snd_pcm_substream *substream,
+	struct snd_dmaengine_dai_dma_data *dma_data,
+	struct snd_pcm_hardware *hw,
+	struct dma_chan *chan)
+{
+	struct dma_slave_caps dma_caps;
+	u32 addr_widths = BIT(DMA_SLAVE_BUSWIDTH_1_BYTE) |
+			  BIT(DMA_SLAVE_BUSWIDTH_2_BYTES) |
+			  BIT(DMA_SLAVE_BUSWIDTH_4_BYTES);
+	snd_pcm_format_t i;
+	int ret = 0;
+
+	if (!hw || !chan || !dma_data)
+		return -EINVAL;
+
+	ret = dma_get_slave_caps(chan, &dma_caps);
+	if (ret == 0) {
+		if (dma_caps.cmd_pause && dma_caps.cmd_resume)
+			hw->info |= SNDRV_PCM_INFO_PAUSE | SNDRV_PCM_INFO_RESUME;
+		if (dma_caps.residue_granularity <= DMA_RESIDUE_GRANULARITY_SEGMENT)
+			hw->info |= SNDRV_PCM_INFO_BATCH;
+
+		if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
+			addr_widths = dma_caps.dst_addr_widths;
+		else
+			addr_widths = dma_caps.src_addr_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.
+	 */
+	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 = SNDRV_PCM_FORMAT_FIRST; 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 |= pcm_format_to_bits(i);
+				break;
+			default:
+				/* Unsupported types */
+				break;
+			}
+		}
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(snd_dmaengine_pcm_refine_runtime_hwparams);
+
 MODULE_LICENSE("GPL");