[PATCH 05/11] ASoC: mmp-sspa: Add support for soc-generic-dmaengine-pcm

From: Lubomir Rintel
Date: Mon May 11 2020 - 17:01:51 EST


This makes the driver usable with the mmp_tdma drier via
soc-generic-dmaengine-pcm. This is conditionalized on DT node (support
for DT is added by a later patch).

A custom mmap callback that creates a NC mapping is used instead of the
default WC one, because with write-combining some bytes don't seem to
make it through for reasons unknown to me.

Signed-off-by: Lubomir Rintel <lkundrak@xxxxx>
---
sound/soc/pxa/mmp-sspa.c | 57 ++++++++++++++++++++++++++++++++++++++++
1 file changed, 57 insertions(+)

diff --git a/sound/soc/pxa/mmp-sspa.c b/sound/soc/pxa/mmp-sspa.c
index 421ffa9fa7b1..6e4b63d0c589 100644
--- a/sound/soc/pxa/mmp-sspa.c
+++ b/sound/soc/pxa/mmp-sspa.c
@@ -386,8 +386,54 @@ static struct snd_soc_dai_driver mmp_sspa_dai = {
.ops = &mmp_sspa_dai_ops,
};

+#define MMP_PCM_INFO (SNDRV_PCM_INFO_MMAP | \
+ SNDRV_PCM_INFO_MMAP_VALID | \
+ SNDRV_PCM_INFO_INTERLEAVED | \
+ SNDRV_PCM_INFO_PAUSE | \
+ SNDRV_PCM_INFO_RESUME | \
+ SNDRV_PCM_INFO_NO_PERIOD_WAKEUP)
+
+static const struct snd_pcm_hardware mmp_pcm_hardware[] = {
+ {
+ .info = MMP_PCM_INFO,
+ .period_bytes_min = 1024,
+ .period_bytes_max = 2048,
+ .periods_min = 2,
+ .periods_max = 32,
+ .buffer_bytes_max = 4096,
+ .fifo_size = 32,
+ },
+ {
+ .info = MMP_PCM_INFO,
+ .period_bytes_min = 1024,
+ .period_bytes_max = 2048,
+ .periods_min = 2,
+ .periods_max = 32,
+ .buffer_bytes_max = 4096,
+ .fifo_size = 32,
+ },
+};
+
+static const struct snd_dmaengine_pcm_config mmp_pcm_config = {
+ .prepare_slave_config = snd_dmaengine_pcm_prepare_slave_config,
+ .pcm_hardware = mmp_pcm_hardware,
+ .prealloc_buffer_size = 4096,
+};
+
+static int mmp_pcm_mmap(struct snd_soc_component *component,
+ struct snd_pcm_substream *substream,
+ struct vm_area_struct *vma)
+{
+ vma->vm_flags |= VM_DONTEXPAND | VM_DONTDUMP;
+ vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
+ return remap_pfn_range(vma, vma->vm_start,
+ substream->dma_buffer.addr >> PAGE_SHIFT,
+ vma->vm_end - vma->vm_start, vma->vm_page_prot);
+}
+
static const struct snd_soc_component_driver mmp_sspa_component = {
.name = "mmp-sspa",
+ .mmap = mmp_pcm_mmap,
};

static int asoc_mmp_sspa_probe(struct platform_device *pdev)
@@ -425,10 +471,21 @@ static int asoc_mmp_sspa_probe(struct platform_device *pdev)
priv->dai_fmt = (unsigned int) -1;
platform_set_drvdata(pdev, priv);

+ priv->playback_dma_data.maxburst = 4;
+ priv->capture_dma_data.maxburst = 4;
/* You know, these addresses are actually ignored. */
priv->playback_dma_data.addr = SSPA_TXD;
priv->capture_dma_data.addr = SSPA_RXD;

+ if (pdev->dev.of_node) {
+ int ret;
+
+ ret = devm_snd_dmaengine_pcm_register(&pdev->dev,
+ &mmp_pcm_config, 0);
+ if (ret)
+ return ret;
+ }
+
return devm_snd_soc_register_component(&pdev->dev, &mmp_sspa_component,
&mmp_sspa_dai, 1);
}
--
2.26.2