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ASoC: fsl_sai: Refine enable/disable TE/RE sequence in trigger() 

Current code enables TCSR.TE and RCSR.RE together, and disable
TCSR.TE and RCSR.RE together in trigger(), which only supports
one operation mode：
1. Rx synchronous with Tx: TE is last enabled and first disabled

Other operation mode need to be considered also:
2. Tx synchronous with Rx: RE is last enabled and first disabled.
3. Asynchronous mode: Tx and Rx are independent.

So the enable TCSR.TE and RCSR.RE sequence and the disable
sequence need to be refined accordingly for #2 and #3.

There is slightly against what RM recommennds with this change.
For example in Rx synchronous with Tx mode, case "aplay 1.wav;
arecord 2.wav" enable TE before RE. But it should be safe to
do so, judging by years of testing results.

Signed-off-by: Shengjiu Wang <shengjiu.wang@nxp.com>
Reviewed-by: Nicolin Chen <nicoleotsuka@gmail.com>
Link: https://lore.kernel.org/r/20200805063413.4610-2-shengjiu.wang@nxp.com
Signed-off-by: Mark Brown <broonie@kernel.org>
This commit is contained in:
Shengjiu Wang 2020-08-05 14:34:11 +08:00 committed by Mark Brown
parent 549ade5721
commit 94741eba63
No known key found for this signature in database
GPG Key ID: 24D68B725D5487D0
1 changed files with 82 additions and 38 deletions
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120
sound/soc/fsl/fsl_sai.c
View File

@ -37,6 +37,24 @@ static const struct snd_pcm_hw_constraint_list fsl_sai_rate_constraints = {
.list = fsl_sai_rates,
};
/**
* fsl_sai_dir_is_synced - Check if stream is synced by the opposite stream
*
* SAI supports synchronous mode using bit/frame clocks of either Transmitter's
* or Receiver's for both streams. This function is used to check if clocks of
* the stream's are synced by the opposite stream.
*
* @sai: SAI context
* @dir: stream direction
*/
static inline bool fsl_sai_dir_is_synced(struct fsl_sai *sai, int dir)
{
int adir = (dir == TX) ? RX : TX;
/* current dir in async mode while opposite dir in sync mode */
return !sai->synchronous[dir] && sai->synchronous[adir];
}
static irqreturn_t fsl_sai_isr(int irq, void *devid)
{
struct fsl_sai *sai = (struct fsl_sai *)devid;
@ -522,6 +540,38 @@ static int fsl_sai_hw_free(struct snd_pcm_substream *substream,
return 0;
}
static void fsl_sai_config_disable(struct fsl_sai *sai, int dir)
{
unsigned int ofs = sai->soc_data->reg_offset;
bool tx = dir == TX;
u32 xcsr, count = 100;
regmap_update_bits(sai->regmap, FSL_SAI_xCSR(tx, ofs),
FSL_SAI_CSR_TERE, 0);
/* TERE will remain set till the end of current frame */
do {
udelay(10);
regmap_read(sai->regmap, FSL_SAI_xCSR(tx, ofs), &xcsr);
} while (--count && xcsr & FSL_SAI_CSR_TERE);
regmap_update_bits(sai->regmap, FSL_SAI_xCSR(tx, ofs),
FSL_SAI_CSR_FR, FSL_SAI_CSR_FR);
/*
* For sai master mode, after several open/close sai,
* there will be no frame clock, and can't recover
* anymore. Add software reset to fix this issue.
* This is a hardware bug, and will be fix in the
* next sai version.
*/
if (!sai->is_slave_mode) {
/* Software Reset */
regmap_write(sai->regmap, FSL_SAI_xCSR(tx, ofs), FSL_SAI_CSR_SR);
/* Clear SR bit to finish the reset */
regmap_write(sai->regmap, FSL_SAI_xCSR(tx, ofs), 0);
}
}
static int fsl_sai_trigger(struct snd_pcm_substream *substream, int cmd,
struct snd_soc_dai *cpu_dai)
@ -530,7 +580,9 @@ static int fsl_sai_trigger(struct snd_pcm_substream *substream, int cmd,
unsigned int ofs = sai->soc_data->reg_offset;
bool tx = substream->stream == SNDRV_PCM_STREAM_PLAYBACK;
u32 xcsr, count = 100;
int adir = tx ? RX : TX;
int dir = tx ? TX : RX;
u32 xcsr;
/*
* Asynchronous mode: Clear SYNC for both Tx and Rx.
@ -553,10 +605,22 @@ static int fsl_sai_trigger(struct snd_pcm_substream *substream, int cmd,
regmap_update_bits(sai->regmap, FSL_SAI_xCSR(tx, ofs),
FSL_SAI_CSR_FRDE, FSL_SAI_CSR_FRDE);
regmap_update_bits(sai->regmap, FSL_SAI_RCSR(ofs),
FSL_SAI_CSR_TERE, FSL_SAI_CSR_TERE);
regmap_update_bits(sai->regmap, FSL_SAI_TCSR(ofs),
regmap_update_bits(sai->regmap, FSL_SAI_xCSR(tx, ofs),
FSL_SAI_CSR_TERE, FSL_SAI_CSR_TERE);
/*
* Enable the opposite direction for synchronous mode
* 1. Tx sync with Rx: only set RE for Rx; set TE & RE for Tx
* 2. Rx sync with Tx: only set TE for Tx; set RE & TE for Rx
*
* RM recommends to enable RE after TE for case 1 and to enable
* TE after RE for case 2, but we here may not always guarantee
* that happens: "arecord 1.wav; aplay 2.wav" in case 1 enables
* TE after RE, which is against what RM recommends but should
* be safe to do, judging by years of testing results.
*/
if (fsl_sai_dir_is_synced(sai, adir))
regmap_update_bits(sai->regmap, FSL_SAI_xCSR((!tx), ofs),
FSL_SAI_CSR_TERE, FSL_SAI_CSR_TERE);
regmap_update_bits(sai->regmap, FSL_SAI_xCSR(tx, ofs),
FSL_SAI_CSR_xIE_MASK, FSL_SAI_FLAGS);
@ -571,43 +635,23 @@ static int fsl_sai_trigger(struct snd_pcm_substream *substream, int cmd,
/* Check if the opposite FRDE is also disabled */
regmap_read(sai->regmap, FSL_SAI_xCSR(!tx, ofs), &xcsr);
if (!(xcsr & FSL_SAI_CSR_FRDE)) {
/* Disable both directions and reset their FIFOs */
regmap_update_bits(sai->regmap, FSL_SAI_TCSR(ofs),
FSL_SAI_CSR_TERE, 0);
regmap_update_bits(sai->regmap, FSL_SAI_RCSR(ofs),
FSL_SAI_CSR_TERE, 0);
/* TERE will remain set till the end of current frame */
do {
udelay(10);
regmap_read(sai->regmap,
FSL_SAI_xCSR(tx, ofs), &xcsr);
} while (--count && xcsr & FSL_SAI_CSR_TERE);
/*
* If opposite stream provides clocks for synchronous mode and
* it is inactive, disable it before disabling the current one
*/
if (fsl_sai_dir_is_synced(sai, adir) && !(xcsr & FSL_SAI_CSR_FRDE))
fsl_sai_config_disable(sai, adir);
regmap_update_bits(sai->regmap, FSL_SAI_TCSR(ofs),
FSL_SAI_CSR_FR, FSL_SAI_CSR_FR);
regmap_update_bits(sai->regmap, FSL_SAI_RCSR(ofs),
FSL_SAI_CSR_FR, FSL_SAI_CSR_FR);
/*
* Disable current stream if either of:
* 1. current stream doesn't provide clocks for synchronous mode
* 2. current stream provides clocks for synchronous mode but no
* more stream is active.
*/
if (!fsl_sai_dir_is_synced(sai, dir) || !(xcsr & FSL_SAI_CSR_FRDE))
fsl_sai_config_disable(sai, dir);
/*
* For sai master mode, after several open/close sai,
* there will be no frame clock, and can't recover
* anymore. Add software reset to fix this issue.
* This is a hardware bug, and will be fix in the
* next sai version.
*/
if (!sai->is_slave_mode) {
/* Software Reset for both Tx and Rx */
regmap_write(sai->regmap, FSL_SAI_TCSR(ofs),
FSL_SAI_CSR_SR);
regmap_write(sai->regmap, FSL_SAI_RCSR(ofs),
FSL_SAI_CSR_SR);
/* Clear SR bit to finish the reset */
regmap_write(sai->regmap, FSL_SAI_TCSR(ofs), 0);
regmap_write(sai->regmap, FSL_SAI_RCSR(ofs), 0);
}
}
break;
default:
return -EINVAL;