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ASoC: fsl_ssi: Add dual fifo mode support 

By enabling dual fifo mode, it would allow SSI enter a better performance
to transimit/receive data without occasional hardware underrun/overrun.

Signed-off-by: Nicolin Chen <b42378@freescale.com>
Acked-by: Timur Tabi <timur@tabi.org>
Acked-by: Mark Brown <broonie@linaro.org>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
This commit is contained in:
Nicolin Chen 2013-11-13 22:55:26 +08:00 committed by Vinod Koul
parent b1d27c79c8
commit 0da9e55e71
1 changed files with 26 additions and 1 deletions
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27
sound/soc/fsl/fsl_ssi.c
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@ -143,6 +143,7 @@ struct fsl_ssi_private {
bool ssi_on_imx;
bool imx_ac97;
bool use_dma;
bool use_dual_fifo;
struct clk *clk;
struct snd_dmaengine_dai_dma_data dma_params_tx;
struct snd_dmaengine_dai_dma_data dma_params_rx;
@ -413,6 +414,12 @@ static int fsl_ssi_setup(struct fsl_ssi_private *ssi_private)
write_ssi(CCSR_SSI_SOR_WAIT(3), &ssi->sor);
}
if (ssi_private->use_dual_fifo) {
write_ssi_mask(&ssi->srcr, 0, CCSR_SSI_SRCR_RFEN1);
write_ssi_mask(&ssi->stcr, 0, CCSR_SSI_STCR_TFEN1);
write_ssi_mask(&ssi->scr, 0, CCSR_SSI_SCR_TCH_EN);
}
return 0;
}
@ -480,6 +487,15 @@ static int fsl_ssi_startup(struct snd_pcm_substream *substream,
ssi_private->second_stream = substream;
}
/* When using dual fifo mode, it is safer to ensure an even period
* size. If appearing to an odd number while DMA always starts its
* task from fifo0, fifo1 would be neglected at the end of each
* period. But SSI would still access fifo1 with an invalid data.
*/
if (ssi_private->use_dual_fifo)
snd_pcm_hw_constraint_step(substream->runtime, 0,
SNDRV_PCM_HW_PARAM_PERIOD_SIZE, 2);
return 0;
}
@ -947,7 +963,7 @@ static int fsl_ssi_probe(struct platform_device *pdev)
ssi_private->fifo_depth = 8;
if (of_device_is_compatible(pdev->dev.of_node, "fsl,imx21-ssi")) {
u32 dma_events[2];
u32 dma_events[2], dmas[4];
ssi_private->ssi_on_imx = true;
ssi_private->clk = devm_clk_get(&pdev->dev, NULL);
@ -1001,6 +1017,15 @@ static int fsl_ssi_probe(struct platform_device *pdev)
dma_events[0], shared ? IMX_DMATYPE_SSI_SP : IMX_DMATYPE_SSI);
imx_pcm_dma_params_init_data(&ssi_private->filter_data_rx,
dma_events[1], shared ? IMX_DMATYPE_SSI_SP : IMX_DMATYPE_SSI);
if (!of_property_read_u32_array(pdev->dev.of_node, "dmas", dmas, 4)
&& dmas[2] == IMX_DMATYPE_SSI_DUAL) {
ssi_private->use_dual_fifo = true;
/* When using dual fifo mode, we need to keep watermark
* as even numbers due to dma script limitation.
*/
ssi_private->dma_params_tx.maxburst &= ~0x1;
ssi_private->dma_params_rx.maxburst &= ~0x1;
}
} else if (ssi_private->use_dma) {
/* The 'name' should not have any slashes in it. */
ret = devm_request_irq(&pdev->dev, ssi_private->irq,