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ASoC: fsl_sai: Reduce race condition during TE/RE enabling

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For trigger start, we don't need to check if it's the first time to
enable TE/RE or second time. It doesn't hurt to enable them any way,
which in the meantime can reduce race condition for TE/RE enabling.

For trigger stop, we will definitely clear FRDE of current direction.
Thus the driver only needs to read the opposite one's.

Signed-off-by: Nicolin Chen <nicoleotsuka@gmail.com>
Signed-off-by: Mark Brown <broonie@linaro.org>
This commit is contained in:
Nicolin Chen 2014-07-23 19:23:38 +08:00 committed by Mark Brown
parent 4800f88b61
commit f4075a8f45
1 changed files with 7 additions and 11 deletions
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18
sound/soc/fsl/fsl_sai.c
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@ -327,7 +327,7 @@ static int fsl_sai_trigger(struct snd_pcm_substream *substream, int cmd,
{
struct fsl_sai *sai = snd_soc_dai_get_drvdata(cpu_dai);
bool tx = substream->stream == SNDRV_PCM_STREAM_PLAYBACK;
u32 tcsr, rcsr;
u32 xcsr;
/*
* The transmitter bit clock and frame sync are to be
@ -338,9 +338,6 @@ static int fsl_sai_trigger(struct snd_pcm_substream *substream, int cmd,
regmap_update_bits(sai->regmap, FSL_SAI_RCR2, FSL_SAI_CR2_SYNC,
FSL_SAI_CR2_SYNC);
regmap_read(sai->regmap, FSL_SAI_TCSR, &tcsr);
regmap_read(sai->regmap, FSL_SAI_RCSR, &rcsr);
/*
* It is recommended that the transmitter is the last enabled
* and the first disabled.
@ -349,12 +346,10 @@ static int fsl_sai_trigger(struct snd_pcm_substream *substream, int cmd,
case SNDRV_PCM_TRIGGER_START:
case SNDRV_PCM_TRIGGER_RESUME:
case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
if (!(tcsr & FSL_SAI_CSR_FRDE || rcsr & FSL_SAI_CSR_FRDE)) {
regmap_update_bits(sai->regmap, FSL_SAI_RCSR,
FSL_SAI_CSR_TERE, FSL_SAI_CSR_TERE);
regmap_update_bits(sai->regmap, FSL_SAI_TCSR,
FSL_SAI_CSR_TERE, FSL_SAI_CSR_TERE);
}
regmap_update_bits(sai->regmap, FSL_SAI_RCSR,
FSL_SAI_CSR_TERE, FSL_SAI_CSR_TERE);
regmap_update_bits(sai->regmap, FSL_SAI_TCSR,
FSL_SAI_CSR_TERE, FSL_SAI_CSR_TERE);
regmap_update_bits(sai->regmap, FSL_SAI_xCSR(tx),
FSL_SAI_CSR_xIE_MASK, FSL_SAI_FLAGS);
@ -370,7 +365,8 @@ static int fsl_sai_trigger(struct snd_pcm_substream *substream, int cmd,
FSL_SAI_CSR_xIE_MASK, 0);
/* Check if the opposite FRDE is also disabled */
if (!(tx ? rcsr & FSL_SAI_CSR_FRDE : tcsr & FSL_SAI_CSR_FRDE)) {
regmap_read(sai->regmap, FSL_SAI_xCSR(!tx), &xcsr);
if (!(xcsr & FSL_SAI_CSR_FRDE)) {
/* Disable both directions and reset their FIFOs */
regmap_update_bits(sai->regmap, FSL_SAI_TCSR,
FSL_SAI_CSR_TERE | FSL_SAI_CSR_FR,