On Fri, Feb 06, 2026 at 09:48:03AM +0800, Shengjiu Wang wrote: > There is a limitation on i.MX952 that dma request is not cleared at the > end of conversion with dma slave mode. Which causes sample is dropped > from the input fifo on the second time if dma is triggered before the > client device and EDMA may copy wrong data from output fifo as the output > fifo is not ready in the beginning. > > The solution is to trigger asrc before dma on i.MX952, and add delay to > wait output data is generated then start the EDMA for output, otherwise > the m2m function has noise issues. > > So add an option to start ASRC first for M2M before ASRC is enabled on > i.MX952. > > Signed-off-by: Shengjiu Wang <[email protected]> > Reviewed-by: Daniel Baluta <[email protected]> > ---
Reviewed-by: Frank Li <[email protected]> > sound/soc/fsl/fsl_asrc.c | 22 ++++++++++++++++++++++ > sound/soc/fsl/fsl_asrc.h | 4 ++++ > sound/soc/fsl/fsl_asrc_common.h | 4 ++++ > sound/soc/fsl/fsl_asrc_m2m.c | 8 +++++++- > 4 files changed, 37 insertions(+), 1 deletion(-) > > diff --git a/sound/soc/fsl/fsl_asrc.c b/sound/soc/fsl/fsl_asrc.c > index 92fb16f7be45..2fe25667c888 100644 > --- a/sound/soc/fsl/fsl_asrc.c > +++ b/sound/soc/fsl/fsl_asrc.c > @@ -1078,6 +1078,26 @@ static unsigned int > fsl_asrc_get_output_fifo_size(struct fsl_asrc_pair *pair) > return val >> ASRFSTi_OUTPUT_FIFO_SHIFT; > } > > +static bool fsl_asrc_m2m_output_ready(struct fsl_asrc_pair *pair) > +{ > + struct fsl_asrc *asrc = pair->asrc; > + enum asrc_pair_index index = pair->index; > + u32 val; > + int ret; > + > + /* Check output fifo status if it exceeds the watermark. */ > + ret = regmap_read_poll_timeout(asrc->regmap, REG_ASRFST(index), val, > + (ASRFSTi_OUTPUT_FIFO_FILL(val) >= > ASRC_M2M_OUTPUTFIFO_WML), > + 1, 1000); > + > + if (ret) { > + pair_warn("output is not ready\n"); > + return false; > + } > + > + return true; > +} > + > static int fsl_asrc_m2m_prepare(struct fsl_asrc_pair *pair) > { > struct fsl_asrc_pair_priv *pair_priv = pair->private; > @@ -1275,6 +1295,7 @@ static int fsl_asrc_probe(struct platform_device *pdev) > > asrc_priv->soc = of_device_get_match_data(&pdev->dev); > asrc->use_edma = asrc_priv->soc->use_edma; > + asrc->start_before_dma = asrc_priv->soc->start_before_dma; > asrc->get_dma_channel = fsl_asrc_get_dma_channel; > asrc->request_pair = fsl_asrc_request_pair; > asrc->release_pair = fsl_asrc_release_pair; > @@ -1289,6 +1310,7 @@ static int fsl_asrc_probe(struct platform_device *pdev) > asrc->m2m_get_maxburst = fsl_asrc_m2m_get_maxburst; > asrc->m2m_pair_resume = fsl_asrc_m2m_pair_resume; > asrc->m2m_get_cap = fsl_asrc_m2m_get_cap; > + asrc->m2m_output_ready = fsl_asrc_m2m_output_ready; > > if (of_device_is_compatible(np, "fsl,imx35-asrc")) { > asrc_priv->clk_map[IN] = input_clk_map_imx35; > diff --git a/sound/soc/fsl/fsl_asrc.h b/sound/soc/fsl/fsl_asrc.h > index 1c492eb237f5..60b6865ca952 100644 > --- a/sound/soc/fsl/fsl_asrc.h > +++ b/sound/soc/fsl/fsl_asrc.h > @@ -257,6 +257,8 @@ > #define ASRFSTi_OUTPUT_FIFO_WIDTH 7 > #define ASRFSTi_OUTPUT_FIFO_SHIFT 12 > #define ASRFSTi_OUTPUT_FIFO_MASK (((1 << ASRFSTi_OUTPUT_FIFO_WIDTH) - 1) > << ASRFSTi_OUTPUT_FIFO_SHIFT) > +#define ASRFSTi_OUTPUT_FIFO_FILL(v) \ > + (((v) & ASRFSTi_OUTPUT_FIFO_MASK) >> ASRFSTi_OUTPUT_FIFO_SHIFT) > #define ASRFSTi_IAEi_SHIFT 11 > #define ASRFSTi_IAEi_MASK (1 << ASRFSTi_IAEi_SHIFT) > #define ASRFSTi_IAEi (1 << ASRFSTi_IAEi_SHIFT) > @@ -432,10 +434,12 @@ struct dma_block { > * > * @use_edma: using edma as dma device or not > * @channel_bits: width of ASRCNCR register for each pair > + * @start_before_dma: start asrc before dma > */ > struct fsl_asrc_soc_data { > bool use_edma; > unsigned int channel_bits; > + bool start_before_dma; > }; > > /** > diff --git a/sound/soc/fsl/fsl_asrc_common.h b/sound/soc/fsl/fsl_asrc_common.h > index 0cd595b0f629..c8a1a2b5915d 100644 > --- a/sound/soc/fsl/fsl_asrc_common.h > +++ b/sound/soc/fsl/fsl_asrc_common.h > @@ -107,6 +107,7 @@ struct fsl_asrc_pair { > * @asrc_rate: default sample rate for ASoC Back-Ends > * @asrc_format: default sample format for ASoC Back-Ends > * @use_edma: edma is used > + * @start_before_dma: start asrc before dma > * @get_dma_channel: function pointer > * @request_pair: function pointer > * @release_pair: function pointer > @@ -116,6 +117,7 @@ struct fsl_asrc_pair { > * @m2m_start: function pointer > * @m2m_unprepare: function pointer > * @m2m_stop: function pointer > + * @m2m_output_ready: function pointer, check output fifo ready or not > * @m2m_calc_out_len: function pointer > * @m2m_get_maxburst: function pointer > * @m2m_pair_suspend: function pointer > @@ -143,6 +145,7 @@ struct fsl_asrc { > int asrc_rate; > snd_pcm_format_t asrc_format; > bool use_edma; > + bool start_before_dma; > > struct dma_chan *(*get_dma_channel)(struct fsl_asrc_pair *pair, bool > dir); > int (*request_pair)(int channels, struct fsl_asrc_pair *pair); > @@ -154,6 +157,7 @@ struct fsl_asrc { > int (*m2m_start)(struct fsl_asrc_pair *pair); > int (*m2m_unprepare)(struct fsl_asrc_pair *pair); > int (*m2m_stop)(struct fsl_asrc_pair *pair); > + bool (*m2m_output_ready)(struct fsl_asrc_pair *pair); > > int (*m2m_calc_out_len)(struct fsl_asrc_pair *pair, int > input_buffer_length); > int (*m2m_get_maxburst)(u8 dir, struct fsl_asrc_pair *pair); > diff --git a/sound/soc/fsl/fsl_asrc_m2m.c b/sound/soc/fsl/fsl_asrc_m2m.c > index f46881f71e43..77999526dd9e 100644 > --- a/sound/soc/fsl/fsl_asrc_m2m.c > +++ b/sound/soc/fsl/fsl_asrc_m2m.c > @@ -253,15 +253,21 @@ static int asrc_m2m_device_run(struct fsl_asrc_pair > *pair, struct snd_compr_task > reinit_completion(&pair->complete[IN]); > reinit_completion(&pair->complete[OUT]); > > + if (asrc->start_before_dma) > + asrc->m2m_start(pair); > + > /* Submit DMA request */ > dmaengine_submit(pair->desc[IN]); > dma_async_issue_pending(pair->desc[IN]->chan); > if (out_dma_len > 0) { > + if (asrc->start_before_dma && asrc->m2m_output_ready) > + asrc->m2m_output_ready(pair); > dmaengine_submit(pair->desc[OUT]); > dma_async_issue_pending(pair->desc[OUT]->chan); > } > > - asrc->m2m_start(pair); > + if (!asrc->start_before_dma) > + asrc->m2m_start(pair); > > if (!wait_for_completion_interruptible_timeout(&pair->complete[IN], 10 > * HZ)) { > dev_err(dev, "out DMA task timeout\n"); > -- > 2.34.1 >
