From 70424d8e6e15abd32e189130be220d0063e082bc Mon Sep 17 00:00:00 2001 From: John Hsu Date: Fri, 1 Dec 2017 10:01:50 +0800 Subject: [PATCH] ASoC: nau8825: improve semaphore control After reviewing the crosstalk protection, there are two flaws at semaphore control. The first one is that the semaphore releases are not enough; and the other is that down_interruptible has an risk to make the ISR sleep. Therefore, the driver add more releases before the funcitons return. Take down_trylock to replace down_interruptible. The ISR can control the protection as well and never sleep by semaphore. Signed-off-by: John Hsu Signed-off-by: Mark Brown --- sound/soc/codecs/nau8825.c | 38 +++++++++++++++++++++++--------------- 1 file changed, 23 insertions(+), 15 deletions(-) diff --git a/sound/soc/codecs/nau8825.c b/sound/soc/codecs/nau8825.c index 603cd72c2a25..5778eadbf9e6 100644 --- a/sound/soc/codecs/nau8825.c +++ b/sound/soc/codecs/nau8825.c @@ -245,13 +245,14 @@ static const unsigned short logtable[256] = { * tasks are allowed to acquire the semaphore, calling this function will * put the task to sleep. If the semaphore is not released within the * specified number of jiffies, this function returns. - * Acquires the semaphore without jiffies. If no more tasks are allowed - * to acquire the semaphore, calling this function will put the task to - * sleep until the semaphore is released. * If the semaphore is not released within the specified number of jiffies, - * this function returns -ETIME. - * If the sleep is interrupted by a signal, this function will return -EINTR. - * It returns 0 if the semaphore was acquired successfully. + * this function returns -ETIME. If the sleep is interrupted by a signal, + * this function will return -EINTR. It returns 0 if the semaphore was + * acquired successfully. + * + * Acquires the semaphore without jiffies. Try to acquire the semaphore + * atomically. Returns 0 if the semaphore has been acquired successfully + * or 1 if it it cannot be acquired. */ static int nau8825_sema_acquire(struct nau8825 *nau8825, long timeout) { @@ -262,8 +263,8 @@ static int nau8825_sema_acquire(struct nau8825 *nau8825, long timeout) if (ret < 0) dev_warn(nau8825->dev, "Acquire semaphore timeout\n"); } else { - ret = down_interruptible(&nau8825->xtalk_sem); - if (ret < 0) + ret = down_trylock(&nau8825->xtalk_sem); + if (ret) dev_warn(nau8825->dev, "Acquire semaphore fail\n"); } @@ -1246,8 +1247,10 @@ static int nau8825_hw_params(struct snd_pcm_substream *substream, regmap_read(nau8825->regmap, NAU8825_REG_DAC_CTRL1, &osr); osr &= NAU8825_DAC_OVERSAMPLE_MASK; if (nau8825_clock_check(nau8825, substream->stream, - params_rate(params), osr)) + params_rate(params), osr)) { + nau8825_sema_release(nau8825); return -EINVAL; + } regmap_update_bits(nau8825->regmap, NAU8825_REG_CLK_DIVIDER, NAU8825_CLK_DAC_SRC_MASK, osr_dac_sel[osr].clk_src << NAU8825_CLK_DAC_SRC_SFT); @@ -1255,8 +1258,10 @@ static int nau8825_hw_params(struct snd_pcm_substream *substream, regmap_read(nau8825->regmap, NAU8825_REG_ADC_RATE, &osr); osr &= NAU8825_ADC_SYNC_DOWN_MASK; if (nau8825_clock_check(nau8825, substream->stream, - params_rate(params), osr)) + params_rate(params), osr)) { + nau8825_sema_release(nau8825); return -EINVAL; + } regmap_update_bits(nau8825->regmap, NAU8825_REG_CLK_DIVIDER, NAU8825_CLK_ADC_SRC_MASK, osr_adc_sel[osr].clk_src << NAU8825_CLK_ADC_SRC_SFT); @@ -1273,8 +1278,10 @@ static int nau8825_hw_params(struct snd_pcm_substream *substream, bclk_div = 1; else if (bclk_fs <= 128) bclk_div = 0; - else + else { + nau8825_sema_release(nau8825); return -EINVAL; + } regmap_update_bits(nau8825->regmap, NAU8825_REG_I2S_PCM_CTRL2, NAU8825_I2S_LRC_DIV_MASK | NAU8825_I2S_BLK_DIV_MASK, ((bclk_div + 1) << NAU8825_I2S_LRC_DIV_SFT) | bclk_div); @@ -1294,6 +1301,7 @@ static int nau8825_hw_params(struct snd_pcm_substream *substream, val_len |= NAU8825_I2S_DL_32; break; default: + nau8825_sema_release(nau8825); return -EINVAL; } @@ -1312,8 +1320,6 @@ static int nau8825_set_dai_fmt(struct snd_soc_dai *codec_dai, unsigned int fmt) struct nau8825 *nau8825 = snd_soc_codec_get_drvdata(codec); unsigned int ctrl1_val = 0, ctrl2_val = 0; - nau8825_sema_acquire(nau8825, 3 * HZ); - switch (fmt & SND_SOC_DAIFMT_MASTER_MASK) { case SND_SOC_DAIFMT_CBM_CFM: ctrl2_val |= NAU8825_I2S_MS_MASTER; @@ -1355,6 +1361,8 @@ static int nau8825_set_dai_fmt(struct snd_soc_dai *codec_dai, unsigned int fmt) return -EINVAL; } + nau8825_sema_acquire(nau8825, 3 * HZ); + regmap_update_bits(nau8825->regmap, NAU8825_REG_I2S_PCM_CTRL1, NAU8825_I2S_DL_MASK | NAU8825_I2S_DF_MASK | NAU8825_I2S_BP_MASK | NAU8825_I2S_PCMB_MASK, @@ -1701,7 +1709,7 @@ static irqreturn_t nau8825_interrupt(int irq, void *data) int ret; nau8825->xtalk_protect = true; ret = nau8825_sema_acquire(nau8825, 0); - if (ret < 0) + if (ret) nau8825->xtalk_protect = false; } /* Startup cross talk detection process */ @@ -2383,7 +2391,7 @@ static int __maybe_unused nau8825_resume(struct snd_soc_codec *codec) regcache_sync(nau8825->regmap); nau8825->xtalk_protect = true; ret = nau8825_sema_acquire(nau8825, 0); - if (ret < 0) + if (ret) nau8825->xtalk_protect = false; enable_irq(nau8825->irq);