From patchwork Fri Dec 1 02:01:50 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: AS50 KCHSU0 X-Patchwork-Id: 10086027 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 4EE5F60327 for ; Fri, 1 Dec 2017 02:10:07 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 3A6442A4E4 for ; Fri, 1 Dec 2017 02:10:07 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 2D3012A4EC; Fri, 1 Dec 2017 02:10:07 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-1.9 required=2.0 tests=BAYES_00, RCVD_IN_DNSWL_NONE autolearn=ham version=3.3.1 Received: from alsa0.perex.cz (alsa0.perex.cz [77.48.224.243]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id C8A962A4E4 for ; Fri, 1 Dec 2017 02:10:05 +0000 (UTC) Received: from alsa0.perex.cz (localhost [127.0.0.1]) by alsa0.perex.cz (Postfix) with ESMTP id 55441267B78; Fri, 1 Dec 2017 03:01:58 +0100 (CET) X-Original-To: alsa-devel@alsa-project.org Delivered-To: alsa-devel@alsa-project.org Received: by alsa0.perex.cz (Postfix, from userid 1000) id EF0C0267B75; Fri, 1 Dec 2017 03:01:55 +0100 (CET) Received: from maillog.nuvoton.com (maillog.nuvoton.com [202.39.227.15]) by alsa0.perex.cz (Postfix) with ESMTP id D3B08267B70 for ; Fri, 1 Dec 2017 03:01:53 +0100 (CET) Received: from NTHCCAS01.nuvoton.com (nthccas01.nuvoton.com [10.1.8.28]) by maillog.nuvoton.com (Postfix) with ESMTP id 488751C80A4F; Fri, 1 Dec 2017 10:01:52 +0800 (CST) Received: from NTHCML01B.nuvoton.com (10.1.8.178) by NTHCCAS01.nuvoton.com (10.1.8.28) with Microsoft SMTP Server (TLS) id 15.0.1130.7; Fri, 1 Dec 2017 10:01:52 +0800 Received: from NTHCCAS01.nuvoton.com (10.1.8.28) by NTHCML01B.nuvoton.com (10.1.8.178) with Microsoft SMTP Server (TLS) id 15.0.1130.7; Fri, 1 Dec 2017 10:01:51 +0800 Received: from localhost.localdomain (10.4.36.27) by NTHCCAS01.nuvoton.com (10.1.12.25) with Microsoft SMTP Server id 15.0.1130.7 via Frontend Transport; Fri, 1 Dec 2017 10:01:51 +0800 From: John Hsu To: Date: Fri, 1 Dec 2017 10:01:50 +0800 Message-ID: <1512093710-11097-1-git-send-email-KCHSU0@nuvoton.com> X-Mailer: git-send-email 2.6.4 MIME-Version: 1.0 Cc: alsa-devel@alsa-project.org, cychiang@google.com, anatol.pomozov@gmail.com, WTLI@nuvoton.com, wuchengli@google.com, John Hsu , lgirdwood@gmail.com, YHCHuang@nuvoton.com, mac.chiang@intel.com, CTLIN0@nuvoton.com, mhkuo@nuvoton.com Subject: [alsa-devel] ASoC: nau8825: improve semaphore control X-BeenThere: alsa-devel@alsa-project.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: "Alsa-devel mailing list for ALSA developers - http://www.alsa-project.org" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: alsa-devel-bounces@alsa-project.org Sender: alsa-devel-bounces@alsa-project.org X-Virus-Scanned: ClamAV using ClamSMTP 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 --- 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 7947b11..2aea642 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"); } @@ -1258,8 +1259,10 @@ 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); @@ -1267,8 +1270,10 @@ 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); @@ -1285,8 +1290,10 @@ 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); @@ -1306,6 +1313,7 @@ static int nau8825_hw_params(struct snd_pcm_substream *substream, val_len |= NAU8825_I2S_DL_32; break; default: + nau8825_sema_release(nau8825); return -EINVAL; } @@ -1324,8 +1332,6 @@ 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; @@ -1367,6 +1373,8 @@ 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, @@ -1713,7 +1721,7 @@ 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 */ @@ -2399,7 +2407,7 @@ 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);