From: Luca Ceresoli <luca@lucaceresoli.net>
To: alsa-devel@alsa-project.org
Cc: Luca Ceresoli <luca@lucaceresoli.net>,
Liam Girdwood <lgirdwood@gmail.com>,
Mark Brown <broonie@kernel.org>, Jaroslav Kysela <perex@perex.cz>,
Takashi Iwai <tiwai@suse.com>,
Lars-Peter Clausen <lars@metafoo.de>,
linux-kernel@vger.kernel.org
Subject: [PATCH 1/1] axi-i2s: set period size register
Date: Fri, 24 Aug 2018 18:04:30 +0200 [thread overview]
Message-ID: <20180824160430.10222-2-luca@lucaceresoli.net> (raw)
In-Reply-To: <20180824160430.10222-1-luca@lucaceresoli.net>
The default value of the PERIOD_LEN register is 0 and results in
axi-i2s keeping TLAST always asserted in its AXI Stream output.
When the AXI Stream is sent to a Xilinx AXI-DMA, this results in the
DMA generating an interrupt flood and ALSA produce a corrupted
recording. This is because AXI-DMA raises an interrupt whenever TLAST
is active.
Fix by setting the PERIOD_LEN register as soon as the period is
known. This way TLAST is emitted once per period, and the DMA raises
interrupts correctly.
Signed-off-by: Luca Ceresoli <luca@lucaceresoli.net>
---
sound/soc/adi/axi-i2s.c | 15 ++++++++++++++-
1 file changed, 14 insertions(+), 1 deletion(-)
diff --git a/sound/soc/adi/axi-i2s.c b/sound/soc/adi/axi-i2s.c
index 4c23381727a1..af581a313a40 100644
--- a/sound/soc/adi/axi-i2s.c
+++ b/sound/soc/adi/axi-i2s.c
@@ -24,6 +24,7 @@
#define AXI_I2S_REG_CTRL 0x04
#define AXI_I2S_REG_CLK_CTRL 0x08
#define AXI_I2S_REG_STATUS 0x10
+#define AXI_I2S_REG_PERIOD_LEN 0x18
#define AXI_I2S_REG_RX_FIFO 0x28
#define AXI_I2S_REG_TX_FIFO 0x2C
@@ -101,6 +102,17 @@ static int axi_i2s_hw_params(struct snd_pcm_substream *substream,
return 0;
}
+static int axi_i2s_prepare(struct snd_pcm_substream *substream,
+ struct snd_soc_dai *dai)
+{
+ struct axi_i2s *i2s = snd_soc_dai_get_drvdata(dai);
+ unsigned int period_bytes = snd_pcm_lib_period_bytes(substream);
+
+ /* adi_i2s counts 32-bit words, thus divide bytes by 4 */
+ return regmap_write(i2s->regmap, AXI_I2S_REG_PERIOD_LEN,
+ (period_bytes / 4) - 1);
+}
+
static int axi_i2s_startup(struct snd_pcm_substream *substream,
struct snd_soc_dai *dai)
{
@@ -147,6 +159,7 @@ static const struct snd_soc_dai_ops axi_i2s_dai_ops = {
.shutdown = axi_i2s_shutdown,
.trigger = axi_i2s_trigger,
.hw_params = axi_i2s_hw_params,
+ .prepare = axi_i2s_prepare,
};
static struct snd_soc_dai_driver axi_i2s_dai = {
@@ -175,7 +188,7 @@ static const struct regmap_config axi_i2s_regmap_config = {
.reg_bits = 32,
.reg_stride = 4,
.val_bits = 32,
- .max_register = AXI_I2S_REG_STATUS,
+ .max_register = AXI_I2S_REG_PERIOD_LEN,
};
static int axi_i2s_probe(struct platform_device *pdev)
--
2.17.1
next prev parent reply other threads:[~2018-08-24 16:05 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-08-24 16:04 [PATCH 0/1] Fix ADI axi-i2s + Xilinx AXI-DMA capture Luca Ceresoli
2018-08-24 16:04 ` Luca Ceresoli [this message]
2018-08-27 12:27 ` [PATCH 1/1] axi-i2s: set period size register Lars-Peter Clausen
2018-08-27 16:22 ` Luca Ceresoli
2018-08-27 16:51 ` Lars-Peter Clausen
2018-08-29 7:15 ` Luca Ceresoli
2018-09-06 8:43 ` Michal Simek
2018-08-28 18:58 ` [PATCH 0/1] Fix ADI axi-i2s + Xilinx AXI-DMA capture Mark Brown
2018-08-29 7:16 ` Luca Ceresoli
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