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ASoC: ti: davinci-i2s: Move the XSYNCERR workaround to .prepare callback 

Currently the driver uses snd_soc_rtdcom_lookup() in it's mcbsp_start
function to try to stop/restart the DMA as the initial XSYNCERR workaround
need to be done before the DMA is armed.

There are couple of things wrong with this:
- the driver crashes with NULL pointer dereference as the
  component->driver->ops is actually NULL
- the driver should not use snd_soc_rtdcom_lookup() in the first place
- Fiddling with DMA is never a good thing

Move the workaround handling to .prepare which is called before the DMA is
armed, so it complies with the requirements.

Reported-by (usage of snd_soc_rtdcom_lookup): Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
Link: https://lore.kernel.org/r/20190830103841.25128-3-peter.ujfalusi@ti.com
Signed-off-by: Mark Brown <broonie@kernel.org>
This commit is contained in:
Peter Ujfalusi 2019-08-30 13:38:39 +03:00 committed by Mark Brown
parent cc9bbb6cde
commit a2dc6f82fd
No known key found for this signature in database
GPG Key ID: 24D68B725D5487D0
1 changed files with 34 additions and 48 deletions
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82
sound/soc/ti/davinci-i2s.c
View File

@ -187,57 +187,9 @@ static void toggle_clock(struct davinci_mcbsp_dev *dev, int playback)
static void davinci_mcbsp_start(struct davinci_mcbsp_dev *dev,
struct snd_pcm_substream *substream)
{
struct snd_soc_pcm_runtime *rtd = substream->private_data;
struct snd_soc_component *component = snd_soc_rtdcom_lookup(rtd, DRV_NAME);
int playback = (substream->stream == SNDRV_PCM_STREAM_PLAYBACK);
u32 spcr;
u32 mask = playback ? DAVINCI_MCBSP_SPCR_XRST : DAVINCI_MCBSP_SPCR_RRST;
spcr = davinci_mcbsp_read_reg(dev, DAVINCI_MCBSP_SPCR_REG);
if (spcr & mask) {
/* start off disabled */
davinci_mcbsp_write_reg(dev, DAVINCI_MCBSP_SPCR_REG,
spcr & ~mask);
toggle_clock(dev, playback);
}
if (dev->pcr & (DAVINCI_MCBSP_PCR_FSXM | DAVINCI_MCBSP_PCR_FSRM |
DAVINCI_MCBSP_PCR_CLKXM | DAVINCI_MCBSP_PCR_CLKRM)) {
/* Start the sample generator */
spcr |= DAVINCI_MCBSP_SPCR_GRST;
davinci_mcbsp_write_reg(dev, DAVINCI_MCBSP_SPCR_REG, spcr);
}
if (playback) {
/* Stop the DMA to avoid data loss */
/* while the transmitter is out of reset to handle XSYNCERR */
if (component->driver->ops->trigger) {
int ret = component->driver->ops->trigger(substream,
SNDRV_PCM_TRIGGER_STOP);
if (ret < 0)
printk(KERN_DEBUG "Playback DMA stop failed\n");
}
/* Enable the transmitter */
spcr = davinci_mcbsp_read_reg(dev, DAVINCI_MCBSP_SPCR_REG);
spcr |= DAVINCI_MCBSP_SPCR_XRST;
davinci_mcbsp_write_reg(dev, DAVINCI_MCBSP_SPCR_REG, spcr);
/* wait for any unexpected frame sync error to occur */
udelay(100);
/* Disable the transmitter to clear any outstanding XSYNCERR */
spcr = davinci_mcbsp_read_reg(dev, DAVINCI_MCBSP_SPCR_REG);
spcr &= ~DAVINCI_MCBSP_SPCR_XRST;
davinci_mcbsp_write_reg(dev, DAVINCI_MCBSP_SPCR_REG, spcr);
toggle_clock(dev, playback);
/* Restart the DMA */
if (component->driver->ops->trigger) {
int ret = component->driver->ops->trigger(substream,
SNDRV_PCM_TRIGGER_START);
if (ret < 0)
printk(KERN_DEBUG "Playback DMA start failed\n");
}
}
/* Enable transmitter or receiver */
spcr = davinci_mcbsp_read_reg(dev, DAVINCI_MCBSP_SPCR_REG);
@ -575,7 +527,41 @@ static int davinci_i2s_prepare(struct snd_pcm_substream *substream,
{
struct davinci_mcbsp_dev *dev = snd_soc_dai_get_drvdata(dai);
int playback = (substream->stream == SNDRV_PCM_STREAM_PLAYBACK);
u32 spcr;
u32 mask = playback ? DAVINCI_MCBSP_SPCR_XRST : DAVINCI_MCBSP_SPCR_RRST;
davinci_mcbsp_stop(dev, playback);
spcr = davinci_mcbsp_read_reg(dev, DAVINCI_MCBSP_SPCR_REG);
if (spcr & mask) {
/* start off disabled */
davinci_mcbsp_write_reg(dev, DAVINCI_MCBSP_SPCR_REG,
spcr & ~mask);
toggle_clock(dev, playback);
}
if (dev->pcr & (DAVINCI_MCBSP_PCR_FSXM | DAVINCI_MCBSP_PCR_FSRM |
DAVINCI_MCBSP_PCR_CLKXM | DAVINCI_MCBSP_PCR_CLKRM)) {
/* Start the sample generator */
spcr |= DAVINCI_MCBSP_SPCR_GRST;
davinci_mcbsp_write_reg(dev, DAVINCI_MCBSP_SPCR_REG, spcr);
}
if (playback) {
/* Enable the transmitter */
spcr = davinci_mcbsp_read_reg(dev, DAVINCI_MCBSP_SPCR_REG);
spcr |= DAVINCI_MCBSP_SPCR_XRST;
davinci_mcbsp_write_reg(dev, DAVINCI_MCBSP_SPCR_REG, spcr);
/* wait for any unexpected frame sync error to occur */
udelay(100);
/* Disable the transmitter to clear any outstanding XSYNCERR */
spcr = davinci_mcbsp_read_reg(dev, DAVINCI_MCBSP_SPCR_REG);
spcr &= ~DAVINCI_MCBSP_SPCR_XRST;
davinci_mcbsp_write_reg(dev, DAVINCI_MCBSP_SPCR_REG, spcr);
toggle_clock(dev, playback);
}
return 0;
}