target/linux/bcm27xx/patches-6.1/950-0894-ASOC-dwc-Improve-DMA-shutdown.patch

   1 From e6baee4502c0228c79408b047096a1259a84353f Mon Sep 17 00:00:00 2001
   2 From: Phil Elwell <phil@raspberrypi.com>
   3 Date: Mon, 3 Jul 2023 10:14:43 +0100
   4 Subject: [PATCH] ASOC: dwc: Improve DMA shutdown
   5
   6 Disabling the I2S interface with outstanding transfers prevents the
   7 DMAC from shutting down, so keep it partially active after a stop.
   8
   9 Signed-off-by: Phil Elwell <phil@raspberrypi.com>
  10 ---
  11  sound/soc/dwc/dwc-i2s.c | 72 ++++++++++++++++++++++++++++++++++++-----
  12  1 file changed, 64 insertions(+), 8 deletions(-)
  13
  14 --- a/sound/soc/dwc/dwc-i2s.c
  15 +++ b/sound/soc/dwc/dwc-i2s.c
  16 @@ -165,24 +165,26 @@ static void i2s_start(struct dw_i2s_dev
  17         i2s_write_reg(dev->i2s_base, CER, 1);
  18  }
  19
  20 -static void i2s_stop(struct dw_i2s_dev *dev,
  21 -               struct snd_pcm_substream *substream)
  22 +static void i2s_pause(struct dw_i2s_dev *dev, struct snd_pcm_substream *substream)
  23  {
  24
  25         i2s_clear_irqs(dev, substream->stream);
  26 -       if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
  27 -               i2s_write_reg(dev->i2s_base, ITER, 0);
  28 -       else
  29 -               i2s_write_reg(dev->i2s_base, IRER, 0);
  30
  31         i2s_disable_irqs(dev, substream->stream, 8);
  32
  33         if (!dev->active) {
  34                 i2s_write_reg(dev->i2s_base, CER, 0);
  35 -               i2s_write_reg(dev->i2s_base, IER, 0);
  36 +               /* Keep the device enabled until the shutdown - do not clear IER */
  37         }
  38  }
  39
  40 +static void i2s_stop(struct dw_i2s_dev *dev, struct snd_pcm_substream *substream)
  41 +{
  42 +       i2s_clear_irqs(dev, substream->stream);
  43 +
  44 +       i2s_disable_irqs(dev, substream->stream, 8);
  45 +}
  46 +
  47  static void dw_i2s_config(struct dw_i2s_dev *dev, int stream)
  48  {
  49         struct i2s_clk_config_data *config = &dev->config;
  50 @@ -288,6 +290,55 @@ static int dw_i2s_hw_params(struct snd_p
  51         return 0;
  52  }
  53
  54 +static int dw_i2s_startup(struct snd_pcm_substream *substream,
  55 +                         struct snd_soc_dai *cpu_dai)
  56 +{
  57 +       struct dw_i2s_dev *dev = snd_soc_dai_get_drvdata(cpu_dai);
  58 +       union dw_i2s_snd_dma_data *dma_data = NULL;
  59 +       u32 dmacr;
  60 +
  61 +       dev_dbg(dev->dev, "%s(%s)\n", __func__, substream->name);
  62 +       if (!(dev->capability & DWC_I2S_RECORD) &&
  63 +           substream->stream == SNDRV_PCM_STREAM_CAPTURE)
  64 +               return -EINVAL;
  65 +
  66 +       if (!(dev->capability & DWC_I2S_PLAY) &&
  67 +           substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
  68 +               return -EINVAL;
  69 +
  70 +       dw_i2s_config(dev, substream->stream);
  71 +       dmacr = i2s_read_reg(dev->i2s_base, DMACR);
  72 +       if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
  73 +               dma_data = &dev->play_dma_data;
  74 +       else if (substream->stream == SNDRV_PCM_STREAM_CAPTURE)
  75 +               dma_data = &dev->capture_dma_data;
  76 +
  77 +       snd_soc_dai_set_dma_data(cpu_dai, substream, (void *)dma_data);
  78 +       i2s_write_reg(dev->i2s_base, DMACR, dmacr);
  79 +
  80 +       return 0;
  81 +}
  82 +
  83 +static void dw_i2s_shutdown(struct snd_pcm_substream *substream,
  84 +                           struct snd_soc_dai *dai)
  85 +{
  86 +       struct dw_i2s_dev *dev = snd_soc_dai_get_drvdata(dai);
  87 +
  88 +       dev_dbg(dev->dev, "%s(%s)\n", __func__, substream->name);
  89 +       i2s_disable_channels(dev, substream->stream);
  90 +       if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
  91 +               i2s_write_reg(dev->i2s_base, ITER, 0);
  92 +       else
  93 +               i2s_write_reg(dev->i2s_base, IRER, 0);
  94 +
  95 +       i2s_disable_irqs(dev, substream->stream, 8);
  96 +
  97 +       if (!dev->active) {
  98 +               i2s_write_reg(dev->i2s_base, CER, 0);
  99 +               i2s_write_reg(dev->i2s_base, IER, 0);
 100 +       }
 101 +}
 102 +
 103  static int dw_i2s_prepare(struct snd_pcm_substream *substream,
 104                           struct snd_soc_dai *dai)
 105  {
 106 @@ -315,9 +366,12 @@ static int dw_i2s_trigger(struct snd_pcm
 107                 i2s_start(dev, substream);
 108                 break;
 109
 110 +       case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
 111 +               dev->active--;
 112 +               i2s_pause(dev, substream);
 113 +               break;
 114         case SNDRV_PCM_TRIGGER_STOP:
 115         case SNDRV_PCM_TRIGGER_SUSPEND:
 116 -       case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
 117                 dev->active--;
 118                 i2s_stop(dev, substream);
 119                 break;
 120 @@ -394,6 +448,8 @@ static int dw_i2s_set_bclk_ratio(struct
 121
 122  static const struct snd_soc_dai_ops dw_i2s_dai_ops = {
 123         .hw_params      = dw_i2s_hw_params,
 124 +       .startup        = dw_i2s_startup,
 125 +       .shutdown       = dw_i2s_shutdown,
 126         .prepare        = dw_i2s_prepare,
 127         .trigger        = dw_i2s_trigger,
 128         .set_fmt        = dw_i2s_set_fmt,