ASoC: OMAP: Use McBSP threshold to playback and capture

This patch changes the way DMA is done in omap-pcm.c
in order to reduce power consumption. There is no need
to have so much SW control in order to have DMA in idle
state during audio streaming. Configuring McBSP threshold value
and DMA to FRAME_SYNC are sufficient.

Signed-off-by: Eduardo Valentin <eduardo.valentin@nokia.com>
Acked-by: Jarkko Nikula <jhnikula@gmail.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

diff --git a/sound/soc/omap/omap-mcbsp.c b/sound/soc/omap/omap-mcbsp.c
index 6e855080e6eaa40be5894bf902b5e513b1f5a615..580de5a8dba6f744c31bb6e03861d8c2763a45cc 100644 (file)
--- a/sound/soc/omap/omap-mcbsp.c
+++ b/sound/soc/omap/omap-mcbsp.c
@@ -139,28 +139,59 @@ static const unsigned long omap34xx_mcbsp_port[][2] = {
 static const unsigned long omap34xx_mcbsp_port[][2] = {};
 #endif
 
+static void omap_mcbsp_set_threshold(struct snd_pcm_substream *substream)
+{
+       struct snd_soc_pcm_runtime *rtd = substream->private_data;
+       struct snd_soc_dai *cpu_dai = rtd->dai->cpu_dai;
+       struct omap_mcbsp_data *mcbsp_data = to_mcbsp(cpu_dai->private_data);
+       int samples = snd_pcm_lib_period_bytes(substream) >> 1;
+
+       /* Configure McBSP internal buffer usage */
+       if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
+               omap_mcbsp_set_tx_threshold(mcbsp_data->bus_id, samples - 1);
+       else
+               omap_mcbsp_set_rx_threshold(mcbsp_data->bus_id, samples - 1);
+}
+
 static int omap_mcbsp_dai_startup(struct snd_pcm_substream *substream,
                                  struct snd_soc_dai *dai)
 {
        struct snd_soc_pcm_runtime *rtd = substream->private_data;
        struct snd_soc_dai *cpu_dai = rtd->dai->cpu_dai;
        struct omap_mcbsp_data *mcbsp_data = to_mcbsp(cpu_dai->private_data);
+       int bus_id = mcbsp_data->bus_id;
        int err = 0;
 
-       if (cpu_is_omap343x() && mcbsp_data->bus_id == 1) {
+       if (!cpu_dai->active)
+               err = omap_mcbsp_request(bus_id);
+
+       if (cpu_is_omap343x()) {
+               int max_period;
+
                /*
                 * McBSP2 in OMAP3 has 1024 * 32-bit internal audio buffer.
                 * Set constraint for minimum buffer size to the same than FIFO
                 * size in order to avoid underruns in playback startup because
                 * HW is keeping the DMA request active until FIFO is filled.
                 */
+               if (bus_id == 1)
+                       snd_pcm_hw_constraint_minmax(substream->runtime,
+                                       SNDRV_PCM_HW_PARAM_BUFFER_BYTES,
+                                       4096, UINT_MAX);
+
+               if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
+                       max_period = omap_mcbsp_get_max_tx_threshold(bus_id);
+               else
+                       max_period = omap_mcbsp_get_max_rx_threshold(bus_id);
+
+               max_period++;
+               max_period <<= 1;
+
                snd_pcm_hw_constraint_minmax(substream->runtime,
-                       SNDRV_PCM_HW_PARAM_BUFFER_BYTES, 4096, UINT_MAX);
+                                               SNDRV_PCM_HW_PARAM_PERIOD_BYTES,
+                                               32, max_period);
        }
 
-       if (!cpu_dai->active)
-               err = omap_mcbsp_request(mcbsp_data->bus_id);
-
        return err;
 }
 
@@ -220,7 +251,7 @@ static int omap_mcbsp_dai_hw_params(struct snd_pcm_substream *substream,
        struct omap_mcbsp_data *mcbsp_data = to_mcbsp(cpu_dai->private_data);
        struct omap_mcbsp_reg_cfg *regs = &mcbsp_data->regs;
        int dma, bus_id = mcbsp_data->bus_id, id = cpu_dai->id;
-       int wlen, channels, wpf;
+       int wlen, channels, wpf, sync_mode = OMAP_DMA_SYNC_ELEMENT;
        unsigned long port;
        unsigned int format;
 
@@ -236,6 +267,9 @@ static int omap_mcbsp_dai_hw_params(struct snd_pcm_substream *substream,
        } else if (cpu_is_omap343x()) {
                dma = omap24xx_dma_reqs[bus_id][substream->stream];
                port = omap34xx_mcbsp_port[bus_id][substream->stream];
+               omap_mcbsp_dai_dma_params[id][substream->stream].set_threshold =
+                                               omap_mcbsp_set_threshold;
+               sync_mode = OMAP_DMA_SYNC_FRAME;
        } else {
                return -ENODEV;
        }
@@ -243,6 +277,7 @@ static int omap_mcbsp_dai_hw_params(struct snd_pcm_substream *substream,
                substream->stream ? "Audio Capture" : "Audio Playback";
        omap_mcbsp_dai_dma_params[id][substream->stream].dma_req = dma;
        omap_mcbsp_dai_dma_params[id][substream->stream].port_addr = port;
+       omap_mcbsp_dai_dma_params[id][substream->stream].sync_mode = sync_mode;
        cpu_dai->dma_data = &omap_mcbsp_dai_dma_params[id][substream->stream];
 
        if (mcbsp_data->configured) {

diff --git a/sound/soc/omap/omap-pcm.c b/sound/soc/omap/omap-pcm.c
index b9633d5a95575a949f2b4ed8a67c7e066f4f1622..5735945788bfda39307322bae71519a277f6ab10 100644 (file)
--- a/sound/soc/omap/omap-pcm.c
+++ b/sound/soc/omap/omap-pcm.c
@@ -162,7 +162,7 @@ static int omap_pcm_prepare(struct snd_pcm_substream *substream)
         */
        dma_params.data_type                    = OMAP_DMA_DATA_TYPE_S16;
        dma_params.trigger                      = dma_data->dma_req;
-       dma_params.sync_mode                    = OMAP_DMA_SYNC_ELEMENT;
+       dma_params.sync_mode                    = dma_data->sync_mode;
        if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) {
                dma_params.src_amode            = OMAP_DMA_AMODE_POST_INC;
                dma_params.dst_amode            = OMAP_DMA_AMODE_CONSTANT;
@@ -205,6 +205,7 @@ static int omap_pcm_trigger(struct snd_pcm_substream *substream, int cmd)
 {
        struct snd_pcm_runtime *runtime = substream->runtime;
        struct omap_runtime_data *prtd = runtime->private_data;
+       struct omap_pcm_dma_data *dma_data = prtd->dma_data;
        unsigned long flags;
        int ret = 0;
 
@@ -214,6 +215,10 @@ static int omap_pcm_trigger(struct snd_pcm_substream *substream, int cmd)
        case SNDRV_PCM_TRIGGER_RESUME:
        case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
                prtd->period_index = 0;
+               /* Configure McBSP internal buffer usage */
+               if (dma_data->set_threshold)
+                       dma_data->set_threshold(substream);
+
                omap_start_dma(prtd->dma_ch);
                break;
 

diff --git a/sound/soc/omap/omap-pcm.h b/sound/soc/omap/omap-pcm.h
index 8d9d26916b05b8868736fa30d071507d1d41ac6d..38a821dd4118f6b1411330013945904ce34bf9cb 100644 (file)
--- a/sound/soc/omap/omap-pcm.h
+++ b/sound/soc/omap/omap-pcm.h
@@ -29,6 +29,8 @@ struct omap_pcm_dma_data {
        char            *name;          /* stream identifier */
        int             dma_req;        /* DMA request line */
        unsigned long   port_addr;      /* transmit/receive register */
+       int             sync_mode;      /* DMA sync mode */
+       void (*set_threshold)(struct snd_pcm_substream *substream);
 };
 
 extern struct snd_soc_platform omap_soc_platform;