ASoC: core - add hostless DAI support
Allow DAI's to be hostless so that no PCM data is sent between DAI
and CPU. This allows for power savings as there is no DMA or CPU
interaction required.
TODO: we shouldn't need to allocate a PAGE for a dummy DMA buffer.
Signed-off-by: Liam Girdwood <lrg@ti.com>
diff --git a/include/sound/soc.h b/include/sound/soc.h
index 82b2403..d40c5ea 100644
--- a/include/sound/soc.h
+++ b/include/sound/soc.h
@@ -210,6 +210,7 @@
#define snd_soc_get_enum_text(soc_enum, idx) \
(soc_enum->texts ? soc_enum->texts[idx] : soc_enum->dtexts[idx])
+
/*
* Bias levels
*
@@ -725,6 +726,8 @@
unsigned int no_codec:1;
/* This DAI has a Backend ID */
unsigned int be_id;
+ /* This DAI can support no host IO (no pcm data is copied to from host) */
+ unsigned int no_host_mode:2;
/* codec/machine specific init - e.g. add machine controls */
int (*init)(struct snd_soc_pcm_runtime *rtd);
diff --git a/sound/soc/soc-core.c b/sound/soc/soc-core.c
index 3005b0d..3add1b8 100644
--- a/sound/soc/soc-core.c
+++ b/sound/soc/soc-core.c
@@ -123,6 +123,24 @@
return 0;
}
+/* ASoC no host IO hardware.
+ * TODO: fine tune these values for all host less transfers.
+ */
+static const struct snd_pcm_hardware no_host_hardware = {
+ .info = SNDRV_PCM_INFO_MMAP |
+ SNDRV_PCM_INFO_MMAP_VALID |
+ SNDRV_PCM_INFO_INTERLEAVED |
+ SNDRV_PCM_INFO_PAUSE |
+ SNDRV_PCM_INFO_RESUME,
+ .formats = SNDRV_PCM_FMTBIT_S16_LE |
+ SNDRV_PCM_FMTBIT_S32_LE,
+ .period_bytes_min = PAGE_SIZE >> 2,
+ .period_bytes_max = PAGE_SIZE >> 1,
+ .periods_min = 2,
+ .periods_max = 4,
+ .buffer_bytes_max = PAGE_SIZE,
+};
+
/* codec register dump */
static ssize_t soc_codec_reg_show(struct snd_soc_codec *codec, char *buf,
size_t count, loff_t pos)
@@ -540,6 +558,9 @@
mutex_lock_nested(&rtd->pcm_mutex, rtd->pcm_subclass);
+ if (rtd->dai_link->no_host_mode == SND_SOC_DAI_LINK_NO_HOST)
+ snd_soc_set_runtime_hwparams(substream, &no_host_hardware);
+
/* startup the audio subsystem */
if (cpu_dai->driver->ops->startup) {
ret = cpu_dai->driver->ops->startup(substream, cpu_dai);
@@ -910,6 +931,19 @@
rtd->rate = params_rate(params);
+ /* malloc a page for hostless IO.
+ * FIXME: rework with alsa-lib changes so that this malloc is not required.
+ */
+ if (rtd->dai_link->no_host_mode == SND_SOC_DAI_LINK_NO_HOST) {
+ substream->dma_buffer.dev.type = SNDRV_DMA_TYPE_DEV;
+ substream->dma_buffer.dev.dev = &rtd->dev;
+ substream->dma_buffer.dev.dev->coherent_dma_mask = ISA_DMA_THRESHOLD;
+ substream->dma_buffer.private_data = NULL;
+
+ ret = snd_pcm_lib_malloc_pages(substream, PAGE_SIZE);
+ if (ret < 0)
+ goto platform_err;
+ }
out:
mutex_unlock(&rtd->pcm_mutex);
return ret;
@@ -962,6 +996,8 @@
if (cpu_dai->driver->ops->hw_free)
cpu_dai->driver->ops->hw_free(substream, cpu_dai);
+ if (rtd->dai_link->no_host_mode == SND_SOC_DAI_LINK_NO_HOST)
+ snd_pcm_lib_free_pages(substream);
mutex_unlock(&rtd->pcm_mutex);
return 0;
}
@@ -2283,6 +2319,16 @@
goto out;
}
+ /* setup any hostless PCMs - i.e. no host IO is performed */
+ if (rtd->dai_link->no_host_mode) {
+ substream[SNDRV_PCM_STREAM_PLAYBACK]->hw_no_buffer = 1;
+ substream[SNDRV_PCM_STREAM_CAPTURE]->hw_no_buffer = 1;
+ snd_soc_set_runtime_hwparams(substream[SNDRV_PCM_STREAM_PLAYBACK],
+ &no_host_hardware);
+ snd_soc_set_runtime_hwparams(substream[SNDRV_PCM_STREAM_CAPTURE],
+ &no_host_hardware);
+ }
+
/* ASoC PCM operations */
if (rtd->dai_link->dynamic) {
rtd->ops.open = soc_dsp_fe_dai_open;