[alsa-devel] [PATCH v3] ASoC: fsl_sai: fix no frame clk in master mode
After several open/close sai test with ctrl+c, there will be I/O error. The SAI can't work anymore, can't recover. There will be no frame clock. With adding the software reset in trigger stop, the issue can be fixed.
This is a hardware bug/errata and reset is the only option.
According to the reference manual, the software reset doesn't reset any control register but only internal hardware logics such as bit clock generator, status flags, and FIFO pointers. (Our purpose is just to reset the clock generator while the software reset is the only way to do that.)
Since slave mode doesn't use the clock generator, only apply the reset procedure to the master mode.
For asynchronous mode, TX will not be reset when RX is still running. In this case, i can't reproduce this issue.
Signed-off-by: Zidan Wang zidan.wang@freescale.com Acked-by: Nicolin Chen nicoleotsuka@gmail.com --- v1->v2: 1) refine the commit log and comments 2) Since slave mode doesn't use the clock generator, only apply the reset procedure to the master mode. v2->v3: add a simple comment in code to describe the hardware bug.
sound/soc/fsl/fsl_sai.c | 18 ++++++++++++++++++ 1 file changed, 18 insertions(+)
diff --git a/sound/soc/fsl/fsl_sai.c b/sound/soc/fsl/fsl_sai.c index 8832901..fef264d 100644 --- a/sound/soc/fsl/fsl_sai.c +++ b/sound/soc/fsl/fsl_sai.c @@ -564,6 +564,24 @@ static int fsl_sai_trigger(struct snd_pcm_substream *substream, int cmd, FSL_SAI_CSR_FR, FSL_SAI_CSR_FR); regmap_update_bits(sai->regmap, FSL_SAI_RCSR, 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, FSL_SAI_CSR_SR); + regmap_write(sai->regmap, + FSL_SAI_RCSR, FSL_SAI_CSR_SR); + /* Clear SR bit to finish the reset */ + regmap_write(sai->regmap, FSL_SAI_TCSR, 0); + regmap_write(sai->regmap, FSL_SAI_RCSR, 0); + } } break; default:
The patch
ASoC: fsl_sai: fix no frame clk in master mode
has been applied to the asoc tree at
git://git.kernel.org/pub/scm/linux/kernel/git/broonie/sound.git
All being well this means that it will be integrated into the linux-next tree (usually sometime in the next 24 hours) and sent to Linus during the next merge window (or sooner if it is a bug fix), however if problems are discovered then the patch may be dropped or reverted.
You may get further e-mails resulting from automated or manual testing and review of the tree, please engage with people reporting problems and send followup patches addressing any issues that are reported if needed.
If any updates are required or you are submitting further changes they should be sent as incremental updates against current git, existing patches will not be replaced.
Please add any relevant lists and maintainers to the CCs when replying to this mail.
Thanks, Mark
From 3e3f8bd569558acefdfaae273d71f7a29b8c0b4f Mon Sep 17 00:00:00 2001
From: Zidan Wang zidan.wang@freescale.com Date: Fri, 18 Dec 2015 16:53:41 +0800 Subject: [PATCH] ASoC: fsl_sai: fix no frame clk in master mode
After several open/close sai test with ctrl+c, there will be I/O error. The SAI can't work anymore, can't recover. There will be no frame clock. With adding the software reset in trigger stop, the issue can be fixed.
This is a hardware bug/errata and reset is the only option.
According to the reference manual, the software reset doesn't reset any control register but only internal hardware logics such as bit clock generator, status flags, and FIFO pointers. (Our purpose is just to reset the clock generator while the software reset is the only way to do that.)
Since slave mode doesn't use the clock generator, only apply the reset procedure to the master mode.
For asynchronous mode, TX will not be reset when RX is still running. In this case, i can't reproduce this issue.
Signed-off-by: Zidan Wang zidan.wang@freescale.com Acked-by: Nicolin Chen nicoleotsuka@gmail.com Signed-off-by: Mark Brown broonie@kernel.org --- sound/soc/fsl/fsl_sai.c | 18 ++++++++++++++++++ 1 file changed, 18 insertions(+)
diff --git a/sound/soc/fsl/fsl_sai.c b/sound/soc/fsl/fsl_sai.c index a4435f5e3be9..a31f0ba527eb 100644 --- a/sound/soc/fsl/fsl_sai.c +++ b/sound/soc/fsl/fsl_sai.c @@ -504,6 +504,24 @@ static int fsl_sai_trigger(struct snd_pcm_substream *substream, int cmd, FSL_SAI_CSR_FR, FSL_SAI_CSR_FR); regmap_update_bits(sai->regmap, FSL_SAI_RCSR, 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, FSL_SAI_CSR_SR); + regmap_write(sai->regmap, + FSL_SAI_RCSR, FSL_SAI_CSR_SR); + /* Clear SR bit to finish the reset */ + regmap_write(sai->regmap, FSL_SAI_TCSR, 0); + regmap_write(sai->regmap, FSL_SAI_RCSR, 0); + } } break; default:
participants (2)
-
Mark Brown -
Zidan Wang