From: Mihai Serban mihai.serban@nxp.com
EDMA requires the period size to be multiple of maxburst. Otherwise the remaining bytes are not transferred and thus noise is produced.
We can handle this issue by adding a constraint on SNDRV_PCM_HW_PARAM_PERIOD_SIZE to be multiple of tx/rx maxburst value.
Signed-off-by: Mihai Serban mihai.serban@nxp.com Signed-off-by: Daniel Baluta daniel.baluta@nxp.com --- Changes since v1: * rename variable to use_edma as per Nicolin's suggestion.
sound/soc/fsl/fsl_sai.c | 15 +++++++++++++++ sound/soc/fsl/fsl_sai.h | 1 + 2 files changed, 16 insertions(+)
diff --git a/sound/soc/fsl/fsl_sai.c b/sound/soc/fsl/fsl_sai.c index ef0b74693093..b517e4bc1b87 100644 --- a/sound/soc/fsl/fsl_sai.c +++ b/sound/soc/fsl/fsl_sai.c @@ -628,6 +628,16 @@ static int fsl_sai_startup(struct snd_pcm_substream *substream, FSL_SAI_CR3_TRCE_MASK, FSL_SAI_CR3_TRCE);
+ /* + * EDMA controller needs period size to be a multiple of + * tx/rx maxburst + */ + if (sai->soc_data->use_edma) + snd_pcm_hw_constraint_step(substream->runtime, 0, + SNDRV_PCM_HW_PARAM_PERIOD_SIZE, + tx ? sai->dma_params_tx.maxburst : + sai->dma_params_rx.maxburst); + ret = snd_pcm_hw_constraint_list(substream->runtime, 0, SNDRV_PCM_HW_PARAM_RATE, &fsl_sai_rate_constraints);
@@ -1026,30 +1036,35 @@ static int fsl_sai_remove(struct platform_device *pdev)
static const struct fsl_sai_soc_data fsl_sai_vf610_data = { .use_imx_pcm = false, + .use_edma = false, .fifo_depth = 32, .reg_offset = 0, };
static const struct fsl_sai_soc_data fsl_sai_imx6sx_data = { .use_imx_pcm = true, + .use_edma = false, .fifo_depth = 32, .reg_offset = 0, };
static const struct fsl_sai_soc_data fsl_sai_imx7ulp_data = { .use_imx_pcm = true, + .use_edma = false, .fifo_depth = 16, .reg_offset = 8, };
static const struct fsl_sai_soc_data fsl_sai_imx8mq_data = { .use_imx_pcm = true, + .use_edma = false, .fifo_depth = 128, .reg_offset = 8, };
static const struct fsl_sai_soc_data fsl_sai_imx8qm_data = { .use_imx_pcm = true, + .use_edma = true, .fifo_depth = 64, .reg_offset = 0, }; diff --git a/sound/soc/fsl/fsl_sai.h b/sound/soc/fsl/fsl_sai.h index b12cb578f6d0..76b15deea80c 100644 --- a/sound/soc/fsl/fsl_sai.h +++ b/sound/soc/fsl/fsl_sai.h @@ -157,6 +157,7 @@
struct fsl_sai_soc_data { bool use_imx_pcm; + bool use_edma; unsigned int fifo_depth; unsigned int reg_offset; };