From mboxrd@z Thu Jan 1 00:00:00 1970 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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id E5E5FC004D4 for ; Thu, 19 Jan 2023 17:27:25 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229926AbjASR1Y (ORCPT ); Thu, 19 Jan 2023 12:27:24 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37058 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229807AbjASR1T (ORCPT ); Thu, 19 Jan 2023 12:27:19 -0500 Received: from mga02.intel.com (mga02.intel.com [134.134.136.20]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 58C8581028 for ; Thu, 19 Jan 2023 09:27:16 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1674149236; x=1705685236; h=message-id:date:mime-version:subject:to:cc:references: from:in-reply-to:content-transfer-encoding; bh=hvKnPzV818Q2MTrJsqR3kbZNsGKViKmjEv5oxYAd76U=; b=iDlaGHmBGBl4x+WrSrZaLcpJizbAlqpIOvi8A26fbhJ68ByAUF5qrNam IIR7yf/FyUf1isc67D95j3wtUCRp/F5vUXqrOzGXhvlJkyBGQJnsDfHFO JmkNSyjfe5R8aHLdUuBRAXHgYDMEIwldi/p/fYfJyw66XhdBlpDHdh6Bm hkV6n46ZXOa4neHwVUYtPwrAdhO7UvT7HukSFXrsJGdIjvpO6fBuj3Ls9 UuEEc4tUHAQ38KkKmHeTydQp90VdWlaEZsJbGWQ1qJAsKCGRuGImJS+wU UL47yOeMSj6tVChV5TdVlp/q6KcB12M0k1CuLUpcxhozsIfw7l6wlO+QD w==; X-IronPort-AV: E=McAfee;i="6500,9779,10595"; a="313243574" X-IronPort-AV: E=Sophos;i="5.97,229,1669104000"; d="scan'208";a="313243574" Received: from fmsmga006.fm.intel.com ([10.253.24.20]) by orsmga101.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 19 Jan 2023 09:27:15 -0800 X-IronPort-AV: E=McAfee;i="6500,9779,10595"; a="905621057" X-IronPort-AV: E=Sophos;i="5.97,229,1669104000"; d="scan'208";a="905621057" Received: from sahamad-mobl1.amr.corp.intel.com (HELO [10.213.187.97]) ([10.213.187.97]) by fmsmga006-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 19 Jan 2023 09:27:15 -0800 Message-ID: Date: Thu, 19 Jan 2023 11:27:14 -0600 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Firefox/102.0 Thunderbird/102.4.2 Subject: Re: [PATCH 1/2] soundwire: bus: Don't filter slave alerts Content-Language: en-US To: Charles Keepax , vkoul@kernel.org Cc: alsa-devel@alsa-project.org, patches@opensource.cirrus.com, linux-kernel@vger.kernel.org, sanyog.r.kale@intel.com, yung-chuan.liao@linux.intel.com References: <20230119165104.3433290-1-ckeepax@opensource.cirrus.com> From: Pierre-Louis Bossart In-Reply-To: <20230119165104.3433290-1-ckeepax@opensource.cirrus.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 1/19/23 10:51, Charles Keepax wrote: > Currently the SoundWire core will loop handling slave alerts but it will > only handle those present when the alert was first raised. This causes > some issues with the Cadence SoundWire IP, which only generates an IRQ > when alert changes state. This means that if a new alert arrives whilst > old alerts are being handled it will not be handled in the currently > loop and then no further alerts will be processed since alert never > changes state to trigger a new IRQ. > > Correct this issue by allowing the core to handle all pending alerts in > the IRQ handling loop. The code will still only loop up to > SDW_READ_INTR_CLEAR_RETRY times, so it shouldn't be possible for it get > completely stuck and if you are generating IRQs faster than you can > handle them you likely have bigger problems anyway. The change makes sense, but it's a bit odd to change the way the interrupts are handled because of a specific design. The bus should be able to deal with various designs, not force a one-size-fits-all policy that may not be quite right in all cases. Could we have a new flag at the bus level that says that peripheral interrupts are not filtered, and set if for the Intel case? We could similarly make the SDW_READ_INTR_CLEAR_RETRY constant bus/platform specific. The SoundWire spec mandates that we re-read the status after clearing the interrupt, but it doesn't say how to deal with recurring interrupts. > Signed-off-by: Charles Keepax > --- > drivers/soundwire/bus.c | 12 ++++-------- > 1 file changed, 4 insertions(+), 8 deletions(-) > > diff --git a/drivers/soundwire/bus.c b/drivers/soundwire/bus.c > index 633d411b64f35..daee2cca94a4d 100644 > --- a/drivers/soundwire/bus.c > +++ b/drivers/soundwire/bus.c > @@ -1560,7 +1560,7 @@ static int sdw_handle_slave_alerts(struct sdw_slave *slave) > unsigned long port; > bool slave_notify; > u8 sdca_cascade = 0; > - u8 buf, buf2[2], _buf, _buf2[2]; > + u8 buf, buf2[2]; > bool parity_check; > bool parity_quirk; > > @@ -1716,9 +1716,9 @@ static int sdw_handle_slave_alerts(struct sdw_slave *slave) > "SDW_SCP_INT1 recheck read failed:%d\n", ret); > goto io_err; > } > - _buf = ret; > + buf = ret; > > - ret = sdw_nread_no_pm(slave, SDW_SCP_INTSTAT2, 2, _buf2); > + ret = sdw_nread_no_pm(slave, SDW_SCP_INTSTAT2, 2, buf2); > if (ret < 0) { > dev_err(&slave->dev, > "SDW_SCP_INT2/3 recheck read failed:%d\n", ret); > @@ -1736,12 +1736,8 @@ static int sdw_handle_slave_alerts(struct sdw_slave *slave) > } > > /* > - * Make sure no interrupts are pending, but filter to limit loop > - * to interrupts identified in the first status read > + * Make sure no interrupts are pending > */ > - buf &= _buf; > - buf2[0] &= _buf2[0]; > - buf2[1] &= _buf2[1]; > stat = buf || buf2[0] || buf2[1] || sdca_cascade; > > /*