[alsa-devel] [PATCH v2] davinci-mcasp: Add support for multichannel playback
Bedia, Vaibhav
vaibhav.bedia at ti.com
Tue Mar 5 12:06:16 CET 2013
Hi Michal,
On Wed, Feb 27, 2013 at 22:08:45, Michal Bachraty wrote:
> Davinci McASP has support for I2S multichannel playback.
> For I2S playback/receive, each serializer is capable to play 2 channels
> (L/R) audio data.Serializer function (Playback-receive-none) is configured
> in DT, depending on hardware specification. It is possible to play less
> channels than configured in DT. For that purpose,only specific number of
> active serializers are enabled. McASP FIFO need to have DMA transfer Bcnt
> set to number of enabled serializers, otherwise no data are transfered to
> McASP and Alsa generates "DMA/IRQ playback write error (DMA or IRQ trouble?)"
> error.
>
Thanks for looking into this. Before going into details, a few generic comments.
All serializers configured in Tx (or Rx) work off common clock generators and
hence the serializers will be operating in sync. I assume the setup that you
have matches this requirement. Based on the DMA programming assumed in the
implementation the user needs to ensure that buffer has the data in the right
format. Can you please describe the setup that you have and how you tested this?
> Signed-off-by: Michal Bachraty <michal.bachraty at streamunlimited.com>
> ---
> sound/soc/davinci/davinci-mcasp.c | 56 ++++++++++++++++++++++++++++++++-----
> sound/soc/davinci/davinci-pcm.c | 16 ++++++-----
> sound/soc/davinci/davinci-pcm.h | 1 +
> 3 files changed, 59 insertions(+), 14 deletions(-)
>
> diff --git a/sound/soc/davinci/davinci-mcasp.c b/sound/soc/davinci/davinci-mcasp.c
> index afef3fb..b84bb73 100644
> --- a/sound/soc/davinci/davinci-mcasp.c
> +++ b/sound/soc/davinci/davinci-mcasp.c
> @@ -235,6 +235,10 @@
> #define DISMOD (val)(val<<2)
> #define TXSTATE BIT(4)
> #define RXSTATE BIT(5)
> +#define SRMOD_MASK 3
> +#define SRMOD_INACTIVE 0
> +#define SRMOD_TX 1
> +#define SRMOD_RX 2
I don't see SRMOD_TX/RX being used anywhere.
>
> /*
> * DAVINCI_MCASP_LBCTL_REG - Loop Back Control Register Bits
> @@ -657,12 +661,15 @@ static int davinci_config_channel_size(struct davinci_audio_dev *dev,
> return 0;
> }
>
> -static void davinci_hw_common_param(struct davinci_audio_dev *dev, int stream)
> +static int davinci_hw_common_param(struct davinci_audio_dev *dev, int stream,
> + int channels)
> {
> int i;
> u8 tx_ser = 0;
> u8 rx_ser = 0;
> -
> + u8 ser;
> + u8 slots = dev->tdm_slots;
> + u8 max_active_serializers = (channels + slots - 1) / slots;
> /* Default configuration */
> mcasp_set_bits(dev->base + DAVINCI_MCASP_PWREMUMGT_REG, MCASP_SOFT);
>
> @@ -680,16 +687,42 @@ static void davinci_hw_common_param(struct davinci_audio_dev *dev, int stream)
> }
>
> for (i = 0; i < dev->num_serializer; i++) {
> + if (dev->serial_dir[i] == TX_MODE)
> + tx_ser++;
> + if (dev->serial_dir[i] == RX_MODE)
> + rx_ser++;
> + }
> +
> + if (stream == SNDRV_PCM_STREAM_PLAYBACK)
> + ser = tx_ser;
> + else
> + ser = rx_ser;
> +
> + if (ser < max_active_serializers) {
> + dev_warn(dev->dev, "stream has more channels (%d) than are "
> + "enabled in mcasp (%d)\n", channels, ser * slots);
> + return -EINVAL;
> + }
> +
> + tx_ser = 0;
> + rx_ser = 0;
The number of active serializers is already being calculated below.
> +
> + for (i = 0; i < dev->num_serializer; i++) {
> mcasp_set_bits(dev->base + DAVINCI_MCASP_XRSRCTL_REG(i),
> dev->serial_dir[i]);
> - if (dev->serial_dir[i] == TX_MODE) {
> + if (dev->serial_dir[i] == TX_MODE &&
> + tx_ser < max_active_serializers) {
> mcasp_set_bits(dev->base + DAVINCI_MCASP_PDIR_REG,
> AXR(i));
> tx_ser++;
> - } else if (dev->serial_dir[i] == RX_MODE) {
> + } else if (dev->serial_dir[i] == RX_MODE &&
> + rx_ser < max_active_serializers) {
> mcasp_clr_bits(dev->base + DAVINCI_MCASP_PDIR_REG,
> AXR(i));
> rx_ser++;
> + } else {
> + mcasp_mod_bits(dev->base + DAVINCI_MCASP_XRSRCTL_REG(i),
> + SRMOD_INACTIVE, SRMOD_MASK);
Sorry I don't follow what you are trying to do here.
> }
> }
>
> @@ -729,6 +762,8 @@ static void davinci_hw_common_param(struct davinci_audio_dev *dev, int stream)
> ((dev->rxnumevt * rx_ser) << 8), NUMEVT_MASK);
> }
> }
> +
> + return 0;
> }
>
> static void davinci_hw_param(struct davinci_audio_dev *dev, int stream)
> @@ -812,8 +847,14 @@ static int davinci_mcasp_hw_params(struct snd_pcm_substream *substream,
> &dev->dma_params[substream->stream];
> int word_length;
> u8 fifo_level;
> + u8 slots = dev->tdm_slots;
> + int channels;
> + struct snd_interval *pcm_channels = hw_param_interval(params,
> + SNDRV_PCM_HW_PARAM_CHANNELS);
> + channels = pcm_channels->min;
>
> - davinci_hw_common_param(dev, substream->stream);
> + if (davinci_hw_common_param(dev, substream->stream, channels))
> + return -EINVAL;
> if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
> fifo_level = dev->txnumevt;
> else
> @@ -862,6 +903,7 @@ static int davinci_mcasp_hw_params(struct snd_pcm_substream *substream,
> dma_params->acnt = dma_params->data_type;
>
> dma_params->fifo_level = fifo_level;
> + dma_params->active_serializers = (channels + slots - 1) / slots;
> davinci_config_channel_size(dev, word_length);
>
> return 0;
> @@ -936,13 +978,13 @@ static struct snd_soc_dai_driver davinci_mcasp_dai[] = {
> .name = "davinci-mcasp.0",
> .playback = {
> .channels_min = 2,
> - .channels_max = 2,
> + .channels_max = 8,
Why are you setting this to 8?
> .rates = DAVINCI_MCASP_RATES,
> .formats = DAVINCI_MCASP_PCM_FMTS,
> },
> .capture = {
> .channels_min = 2,
> - .channels_max = 2,
> + .channels_max = 8,
Same here.
> .rates = DAVINCI_MCASP_RATES,
> .formats = DAVINCI_MCASP_PCM_FMTS,
> },
> diff --git a/sound/soc/davinci/davinci-pcm.c b/sound/soc/davinci/davinci-pcm.c
> index bb57552..3af8b50 100644
> --- a/sound/soc/davinci/davinci-pcm.c
> +++ b/sound/soc/davinci/davinci-pcm.c
> @@ -182,6 +182,7 @@ static void davinci_pcm_enqueue_dma(struct snd_pcm_substream *substream)
> unsigned short acnt;
> unsigned int count;
> unsigned int fifo_level;
> + unsigned char serializers = prtd->params->active_serializers;
Can you please describe what DMA configuration you want? I think you can
get rid of the active_serializers configuration by making use of tx_num_evt.
>
> period_size = snd_pcm_lib_period_bytes(substream);
> dma_offset = prtd->period * period_size;
> @@ -195,14 +196,14 @@ static void davinci_pcm_enqueue_dma(struct snd_pcm_substream *substream)
> data_type = prtd->params->data_type;
> count = period_size / data_type;
> if (fifo_level)
> - count /= fifo_level;
> + count /= fifo_level * serializers;
I think there's a problem is the way in which tx_num_evt is interpreted in the current code.
Instead of setting to fifo_level to tx_num_evt, if you set it to tx_num_evt * num_serializers
you can get rid of the additional code to take care of the number of serializers.
>
> if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) {
> src = dma_pos;
> dst = prtd->params->dma_addr;
> src_bidx = data_type;
> - dst_bidx = 0;
> - src_cidx = data_type * fifo_level;
> + dst_bidx = 4;
Err.. this will most likely break other audio configurations. You should look at how to
avoid this change by making use of the mask and rotation operations in the McASP code.
> + src_cidx = data_type * fifo_level * serializers;
> dst_cidx = 0;
> } else {
> src = prtd->params->dma_addr;
> @@ -210,7 +211,7 @@ static void davinci_pcm_enqueue_dma(struct snd_pcm_substream *substream)
> src_bidx = 0;
> dst_bidx = data_type;
> src_cidx = 0;
> - dst_cidx = data_type * fifo_level;
> + dst_cidx = data_type * fifo_level * serializers;
With the change in fifo_level as described above, this won't be necessary.
> }
>
> acnt = prtd->params->acnt;
> @@ -224,9 +225,10 @@ static void davinci_pcm_enqueue_dma(struct snd_pcm_substream *substream)
> edma_set_transfer_params(prtd->asp_link[0], acnt, count, 1, 0,
> ASYNC);
> else
> - edma_set_transfer_params(prtd->asp_link[0], acnt, fifo_level,
> - count, fifo_level,
> - ABSYNC);
> + edma_set_transfer_params(prtd->asp_link[0], acnt,
> + fifo_level * serializers,
> + count, fifo_level * serializers,
> + ABSYNC);
Same comment applies here.
Regards,
Vaibhav
More information about the Alsa-devel
mailing list