target/linux/bcm27xx/patches-6.1/950-1176-ASoC-dwc-Fix-full-duplex-mode.patch

   1 From cbc65d9c95088d1437a5a84c7d6628b8d27a86f1 Mon Sep 17 00:00:00 2001
   2 From: Phil Elwell <phil@raspberrypi.com>
   3 Date: Tue, 28 Nov 2023 12:14:03 +0000
   4 Subject: [PATCH] ASoC: dwc: Fix full-duplex mode
   5
   6 Configuration of the DMA register was carelessly zeroing bits that may
   7 used by a stream in the other direction. Preserve them instead.
   8
   9 See: https://github.com/raspberrypi/linux/issues/5741
  10
  11 Signed-off-by: Phil Elwell <phil@raspberrypi.com>
  12 ---
  13  sound/soc/dwc/dwc-i2s.c | 20 +++++++++++++-------
  14  1 file changed, 13 insertions(+), 7 deletions(-)
  15
  16 --- a/sound/soc/dwc/dwc-i2s.c
  17 +++ b/sound/soc/dwc/dwc-i2s.c
  18 @@ -189,10 +189,17 @@ static void dw_i2s_config(struct dw_i2s_
  19  {
  20         struct i2s_clk_config_data *config = &dev->config;
  21         u32 ch_reg;
  22 -       u32 dmacr = 0;
  23 +       u32 dmacr;
  24
  25         i2s_disable_channels(dev, stream);
  26
  27 +       dmacr = i2s_read_reg(dev->i2s_base, DMACR);
  28 +
  29 +       if (stream == SNDRV_PCM_STREAM_PLAYBACK)
  30 +               dmacr &= ~(DMACR_DMAEN_TXCH0 * 0xf);
  31 +       else
  32 +               dmacr &= ~(DMACR_DMAEN_RXCH0 * 0xf);
  33 +
  34         for (ch_reg = 0; ch_reg < (config->chan_nr / 2); ch_reg++) {
  35                 if (stream == SNDRV_PCM_STREAM_PLAYBACK) {
  36                         i2s_write_reg(dev->i2s_base, TCR(ch_reg),
  37 @@ -210,10 +217,6 @@ static void dw_i2s_config(struct dw_i2s_
  38                         dmacr |= (DMACR_DMAEN_RXCH0 << ch_reg);
  39                 }
  40         }
  41 -       if (stream == SNDRV_PCM_STREAM_PLAYBACK)
  42 -               dmacr |= DMACR_DMAEN_TX;
  43 -       else if (stream == SNDRV_PCM_STREAM_CAPTURE)
  44 -               dmacr |= DMACR_DMAEN_RX;
  45
  46         i2s_write_reg(dev->i2s_base, DMACR, dmacr);
  47  }
  48 @@ -319,10 +322,13 @@ static int dw_i2s_startup(struct snd_pcm
  49
  50         dw_i2s_config(dev, substream->stream);
  51         dmacr = i2s_read_reg(dev->i2s_base, DMACR);
  52 -       if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
  53 +       if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) {
  54                 dma_data = &dev->play_dma_data;
  55 -       else if (substream->stream == SNDRV_PCM_STREAM_CAPTURE)
  56 +               dmacr |= DMACR_DMAEN_TX;
  57 +       } else if (substream->stream == SNDRV_PCM_STREAM_CAPTURE) {
  58                 dma_data = &dev->capture_dma_data;
  59 +               dmacr |= DMACR_DMAEN_RX;
  60 +       }
  61
  62         snd_soc_dai_set_dma_data(cpu_dai, substream, (void *)dma_data);
  63         i2s_write_reg(dev->i2s_base, DMACR, dmacr);