From patchwork Thu Jun 29 14:10:34 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sascha Hauer X-Patchwork-Id: 13297064 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from alsa0.perex.cz (alsa0.perex.cz [77.48.224.243]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id F2DA0EB64D9 for ; Thu, 29 Jun 2023 14:12:27 +0000 (UTC) Received: from alsa1.perex.cz (alsa1.perex.cz [207.180.221.201]) (using TLSv1.2 with cipher ADH-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by alsa0.perex.cz (Postfix) with ESMTPS id 96488845; Thu, 29 Jun 2023 16:11:35 +0200 (CEST) DKIM-Filter: OpenDKIM Filter v2.11.0 alsa0.perex.cz 96488845 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=alsa-project.org; s=default; t=1688047945; bh=b8dXG8qqAmEn+KZIa3/idP8bhKO1odtgGPWglSAm2nk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-Id: List-Archive:List-Help:List-Owner:List-Post:List-Subscribe: List-Unsubscribe:From; b=TS4UpaP/+G0ouoTPhWbrn7lqetaki7PyYSDmh6wRvwxQch3ZjQZyrqHu6/nDGP7Tx kf/sqGyMCRg18HWemHCoY0wtv6hFswGsYn2CURXj8Fy7ixGWSTVOpEG2GmE/oY4Pjs oDf8P+kfiruxK78k3wUtZHxrKnqbE0tcWlLKcSPU= Received: by alsa1.perex.cz (Postfix, from userid 50401) id AB7FEF800E3; Thu, 29 Jun 2023 16:10:46 +0200 (CEST) Received: from mailman-core.alsa-project.org (mailman-core.alsa-project.org [10.254.200.10]) by alsa1.perex.cz (Postfix) with ESMTP id 10C72F800E3; Thu, 29 Jun 2023 16:10:46 +0200 (CEST) Received: by alsa1.perex.cz (Postfix, from userid 50401) id 98802F8027B; Thu, 29 Jun 2023 16:10:40 +0200 (CEST) Received: from metis.ext.pengutronix.de (metis.ext.pengutronix.de [IPv6:2001:67c:670:201:290:27ff:fe1d:cc33]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange ECDHE (P-256) server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) by alsa1.perex.cz (Postfix) with ESMTPS id 2B922F80246 for ; Thu, 29 Jun 2023 16:10:37 +0200 (CEST) DKIM-Filter: OpenDKIM Filter v2.11.0 alsa1.perex.cz 2B922F80246 Received: from drehscheibe.grey.stw.pengutronix.de ([2a0a:edc0:0:c01:1d::a2]) by metis.ext.pengutronix.de with esmtps (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1qEsM0-0004bc-EC; Thu, 29 Jun 2023 16:10:36 +0200 Received: from [2a0a:edc0:0:1101:1d::28] (helo=dude02.red.stw.pengutronix.de) by drehscheibe.grey.stw.pengutronix.de with esmtp (Exim 4.94.2) (envelope-from ) id 1qEsLz-00AvCr-Nq; Thu, 29 Jun 2023 16:10:35 +0200 Received: from sha by dude02.red.stw.pengutronix.de with local (Exim 4.94.2) (envelope-from ) id 1qEsLy-00BC2x-Vm; Thu, 29 Jun 2023 16:10:34 +0200 From: Sascha Hauer To: alsa-devel@alsa-project.org Cc: Shengjiu Wang , Xiubo Li , Fabio Estevam , Nicolin Chen , Liam Girdwood , Mark Brown , Ahmad Fatoum , Sascha Hauer Subject: [PATCH v2 2/2] ASoC: fsl_sai: Fill Tx FIFO to avoid initial underruns Date: Thu, 29 Jun 2023 16:10:34 +0200 Message-Id: <20230629141034.2659669-3-s.hauer@pengutronix.de> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20230629141034.2659669-1-s.hauer@pengutronix.de> References: <20230629141034.2659669-1-s.hauer@pengutronix.de> MIME-Version: 1.0 X-SA-Exim-Connect-IP: 2a0a:edc0:0:c01:1d::a2 X-SA-Exim-Mail-From: sha@pengutronix.de X-SA-Exim-Scanned: No (on metis.ext.pengutronix.de); SAEximRunCond expanded to false X-PTX-Original-Recipient: alsa-devel@alsa-project.org Message-ID-Hash: 7OGEN474P7BVJSJK4MPQMZCTEV5Z2RNE X-Message-ID-Hash: 7OGEN474P7BVJSJK4MPQMZCTEV5Z2RNE X-MailFrom: sha@pengutronix.de X-Mailman-Rule-Misses: dmarc-mitigation; no-senders; approved; emergency; loop; banned-address; member-moderation; header-match-alsa-devel.alsa-project.org-0; header-match-alsa-devel.alsa-project.org-1; nonmember-moderation; administrivia; implicit-dest; max-recipients; max-size; news-moderation; no-subject; digests; suspicious-header X-Mailman-Version: 3.3.8 Precedence: list List-Id: "Alsa-devel mailing list for ALSA developers - http://www.alsa-project.org" Archived-At: List-Archive: List-Help: List-Owner: List-Post: List-Subscribe: List-Unsubscribe: From: Ahmad Fatoum JACK handles XRuns by stopping and start the ALSA device. On occasion, this leads to early underruns on start leading to reorderd output channels. By filling the FIFO initially, we can avoid these early underruns. This is also suggested by the i.MX8MM reference manual: "If the Transmit FIFO is empty, then to avoid a FIFO underrun, the Transmit Data Register must be written at least 3 bit clocks before the start of the next unmasked word. Before enabling the transmitter, the Transmit FIFO should be initialized with data (since after the transmitter is enabled, the transmitter will start a new frame, and if no data is in the FIFO, then the transmitter will immediately give an error)" [1]: Rev. 0, 02/2019, 13.9.3.5.2 FIFO pointers Fixes: 435508214942 ("ASoC: Add SAI SoC Digital Audio Interface driver.") Signed-off-by: Ahmad Fatoum Signed-off-by: Sascha Hauer --- Notes: Changes since v1: - Add missing Signed-off-by sound/soc/fsl/fsl_sai.c | 18 ++++++++++++++++++ sound/soc/fsl/fsl_sai.h | 1 + 2 files changed, 19 insertions(+) diff --git a/sound/soc/fsl/fsl_sai.c b/sound/soc/fsl/fsl_sai.c index 36f6115469843..6a4f990110d91 100644 --- a/sound/soc/fsl/fsl_sai.c +++ b/sound/soc/fsl/fsl_sai.c @@ -755,6 +755,21 @@ static void fsl_sai_config_disable(struct fsl_sai *sai, int dir) } } +static void fsl_sai_tx_fill_fifo(struct fsl_sai *sai, + struct snd_pcm_runtime *runtime) +{ + u32 slots, slot_width, pins; + int i; + + slot_width = sai->slot_width ?: snd_pcm_format_physical_width(runtime->format); + + slots = fsl_sai_get_tdm_slots(sai, runtime->channels, slot_width); + pins = DIV_ROUND_UP(runtime->channels, slots); + + for (i = 0; i < runtime->channels; i++) + regmap_write(sai->regmap, FSL_SAI_TDR(i % pins), 0x0); +} + static int fsl_sai_trigger(struct snd_pcm_substream *substream, int cmd, struct snd_soc_dai *cpu_dai) { @@ -784,6 +799,9 @@ static int fsl_sai_trigger(struct snd_pcm_substream *substream, int cmd, case SNDRV_PCM_TRIGGER_START: case SNDRV_PCM_TRIGGER_RESUME: case SNDRV_PCM_TRIGGER_PAUSE_RELEASE: + /* Fill FIFO to avoid initial underruns */ + if (tx) + fsl_sai_tx_fill_fifo(sai, substream->runtime); regmap_update_bits(sai->regmap, FSL_SAI_xCSR(tx, ofs), FSL_SAI_CSR_FRDE, FSL_SAI_CSR_FRDE); diff --git a/sound/soc/fsl/fsl_sai.h b/sound/soc/fsl/fsl_sai.h index a53c4f0e25faf..66a136d97a441 100644 --- a/sound/soc/fsl/fsl_sai.h +++ b/sound/soc/fsl/fsl_sai.h @@ -34,6 +34,7 @@ #define FSL_SAI_TDR5 0x34 /* SAI Transmit Data 5 */ #define FSL_SAI_TDR6 0x38 /* SAI Transmit Data 6 */ #define FSL_SAI_TDR7 0x3C /* SAI Transmit Data 7 */ +#define FSL_SAI_TDR(ofs) (FSL_SAI_TDR0 + (ofs) * 4) #define FSL_SAI_TFR0 0x40 /* SAI Transmit FIFO 0 */ #define FSL_SAI_TFR1 0x44 /* SAI Transmit FIFO 1 */ #define FSL_SAI_TFR2 0x48 /* SAI Transmit FIFO 2 */