Current code enables TCSR.TE and RCSR.RE together, and disable TCSR.TE and RCSR.RE together in trigger(), which only supports one operation modeļ¼ 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 --- sound/soc/fsl/fsl_sai.c | 126 +++++++++++++++++++++++++++------------- 1 file changed, 85 insertions(+), 41 deletions(-)
diff --git a/sound/soc/fsl/fsl_sai.c b/sound/soc/fsl/fsl_sai.c index cdff739924e2..566c4747362a 100644 --- a/sound/soc/fsl/fsl_sai.c +++ b/sound/soc/fsl/fsl_sai.c @@ -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); - - 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); - - /* - * 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); - } - } + + /* + * 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); + + /* + * 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); + break; default: return -EINVAL;