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From cbc65d9c95088d1437a5a84c7d6628b8d27a86f1 Mon Sep 17 00:00:00 2001
From: Phil Elwell <phil@raspberrypi.com>
Date: Tue, 28 Nov 2023 12:14:03 +0000
Subject: [PATCH] ASoC: dwc: Fix full-duplex mode
Configuration of the DMA register was carelessly zeroing bits that may
used by a stream in the other direction. Preserve them instead.
See: https://github.com/raspberrypi/linux/issues/5741
Signed-off-by: Phil Elwell <phil@raspberrypi.com>
---
sound/soc/dwc/dwc-i2s.c | 20 +++++++++++++-------
1 file changed, 13 insertions(+), 7 deletions(-)
--- a/sound/soc/dwc/dwc-i2s.c
+++ b/sound/soc/dwc/dwc-i2s.c
@@ -189,10 +189,17 @@ static void dw_i2s_config(struct dw_i2s_
{
struct i2s_clk_config_data *config = &dev->config;
u32 ch_reg;
- u32 dmacr = 0;
+ u32 dmacr;
i2s_disable_channels(dev, stream);
+ dmacr = i2s_read_reg(dev->i2s_base, DMACR);
+
+ if (stream == SNDRV_PCM_STREAM_PLAYBACK)
+ dmacr &= ~(DMACR_DMAEN_TXCH0 * 0xf);
+ else
+ dmacr &= ~(DMACR_DMAEN_RXCH0 * 0xf);
+
for (ch_reg = 0; ch_reg < (config->chan_nr / 2); ch_reg++) {
if (stream == SNDRV_PCM_STREAM_PLAYBACK) {
i2s_write_reg(dev->i2s_base, TCR(ch_reg),
@@ -210,10 +217,6 @@ static void dw_i2s_config(struct dw_i2s_
dmacr |= (DMACR_DMAEN_RXCH0 << ch_reg);
}
}
- if (stream == SNDRV_PCM_STREAM_PLAYBACK)
- dmacr |= DMACR_DMAEN_TX;
- else if (stream == SNDRV_PCM_STREAM_CAPTURE)
- dmacr |= DMACR_DMAEN_RX;
i2s_write_reg(dev->i2s_base, DMACR, dmacr);
}
@@ -319,10 +322,13 @@ static int dw_i2s_startup(struct snd_pcm
dw_i2s_config(dev, substream->stream);
dmacr = i2s_read_reg(dev->i2s_base, DMACR);
- if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
+ if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) {
dma_data = &dev->play_dma_data;
- else if (substream->stream == SNDRV_PCM_STREAM_CAPTURE)
+ dmacr |= DMACR_DMAEN_TX;
+ } else if (substream->stream == SNDRV_PCM_STREAM_CAPTURE) {
dma_data = &dev->capture_dma_data;
+ dmacr |= DMACR_DMAEN_RX;
+ }
snd_soc_dai_set_dma_data(cpu_dai, substream, (void *)dma_data);
i2s_write_reg(dev->i2s_base, DMACR, dmacr);
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