diff options
author | Shengjiu Wang <shengjiu.wang@nxp.com> | 2020-08-05 14:34:11 +0800 |
---|---|---|
committer | Mark Brown <broonie@kernel.org> | 2020-08-17 14:56:49 +0100 |
commit | 94741eba63c23b0f1527b0ae0125e6b553bde10e (patch) | |
tree | 70e5e3aed0944f29e3bfec9747602198a4876635 /sound/soc/fsl/fsl_sai.c | |
parent | 549ade5721fe197b78165fc3476af1fe0c65f089 (diff) | |
download | linux-94741eba63c23b0f1527b0ae0125e6b553bde10e.tar.bz2 |
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 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>
Link: https://lore.kernel.org/r/20200805063413.4610-2-shengjiu.wang@nxp.com
Signed-off-by: Mark Brown <broonie@kernel.org>
Diffstat (limited to 'sound/soc/fsl/fsl_sai.c')
-rw-r--r-- | sound/soc/fsl/fsl_sai.c | 126 |
1 files 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; |