Thread (6 messages) 6 messages, 3 authors, 2019-07-03

Re: [PATCH V2 2/2] ASoC: fsl_esai: recover the channel swap after xrun

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From: Nicolin Chen <nicoleotsuka@gmail.com>
Date: 2019-07-03 09:32:21
Also in: alsa-devel, lkml

On Wed, Jul 03, 2019 at 02:42:05PM +0800, shengjiu.wang@nxp.com wrote:
quoted hunk ↗ jump to hunk
From: Shengjiu Wang <redacted>

There is chip errata ERR008000, the reference doc is
(https://www.nxp.com/docs/en/errata/IMX6DQCE.pdf),

The issue is "While using ESAI transmit or receive and
an underrun/overrun happens, channel swap may occur.
The only recovery mechanism is to reset the ESAI."

This issue exist in imx3/imx5/imx6(partial) series.

In this commit add a tasklet to handle reset of ESAI
after xrun happens to recover the channel swap.

Signed-off-by: Shengjiu Wang <redacted>
---
 sound/soc/fsl/fsl_esai.c | 76 ++++++++++++++++++++++++++++++++++++++++
 1 file changed, 76 insertions(+)
diff --git a/sound/soc/fsl/fsl_esai.c b/sound/soc/fsl/fsl_esai.c
index 20039ae9893b..8c92e49ad6d8 100644
--- a/sound/soc/fsl/fsl_esai.c
+++ b/sound/soc/fsl/fsl_esai.c
+static void fsl_esai_reset(unsigned long arg)
Similarly fsl_esai_hw_reset? This one isn't really that bad though,
yet it feels better to have function naming in a similar style.
quoted hunk ↗ jump to hunk
+{
+	struct fsl_esai *esai_priv = (struct fsl_esai *)arg;
+	u32 saisr, tfcr, rfcr;
+
+	/* save the registers */
+	regmap_read(esai_priv->regmap, REG_ESAI_TFCR, &tfcr);
+	regmap_read(esai_priv->regmap, REG_ESAI_RFCR, &rfcr);
Instead of having this implicit comments, we could have:
+	bool tx = true, rx = false, enabled[2];
+
+	regmap_read(esai_priv->regmap, REG_ESAI_TFCR, &tfcr);
+	regmap_read(esai_priv->regmap, REG_ESAI_RFCR, &rfcr);
+	enabled[tx] = tfcr & ESAI_xFCR_xFEN;
+	enabled[rx] = rfcr & ESAI_xFCR_xFEN;
quoted hunk ↗ jump to hunk
+
+	/* stop the tx & rx */
+	fsl_esai_trigger_stop(esai_priv, 1);
+	fsl_esai_trigger_stop(esai_priv, 0);
And we could reuse the boolean 'tx' and 'rx' here.
quoted hunk ↗ jump to hunk
+
+	/* reset the esai, and restore the registers */
+	fsl_esai_init(esai_priv);
+
[...]
quoted hunk ↗ jump to hunk
+	regmap_update_bits(esai_priv->regmap, REG_ESAI_TCR,
+			   ESAI_xCR_xPR_MASK,
+			   ESAI_xCR_xPR);
+	regmap_update_bits(esai_priv->regmap, REG_ESAI_RCR,
+			   ESAI_xCR_xPR_MASK,
+			   ESAI_xCR_xPR);
Mask and value might fit into one line?
quoted hunk ↗ jump to hunk
+
+	/* restore registers by regcache_sync */
+	fsl_esai_register_restore(esai_priv);
+
+	regmap_update_bits(esai_priv->regmap, REG_ESAI_TCR,
+			   ESAI_xCR_xPR_MASK, 0);
+	regmap_update_bits(esai_priv->regmap, REG_ESAI_RCR,
+			   ESAI_xCR_xPR_MASK, 0);
And just for curious, can (or shall) we stuff this personal reset
to the reset() function? I found this one is a part of the reset
routine being mentioned in the RM -- it was done after ESAI reset
is done via ECR register.

[...]
quoted hunk ↗ jump to hunk
+	regmap_update_bits(esai_priv->regmap, REG_ESAI_PRRC,
+			   ESAI_PRRC_PDC_MASK,
+			   ESAI_PRRC_PDC(ESAI_GPIO));
+	regmap_update_bits(esai_priv->regmap, REG_ESAI_PCRC,
+			   ESAI_PCRC_PC_MASK,
+			   ESAI_PCRC_PC(ESAI_GPIO));
Mask and value might fit into one line?
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