From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-ej1-f45.google.com (mail-ej1-f45.google.com [209.85.218.45]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 3B98027701 for ; Mon, 17 Mar 2025 11:56:20 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.218.45 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1742212583; cv=none; b=JZCcD0U4bHFew0cjKBoBY7XmDEWQD9fImMtLMugW33Tk3bidFb2/oUyE/va2cU8hxOBRFtjgpjSKctRXlVDaAtQ4OddredEc8hCt63MWHGFCuHopSrdxsWf/Z6RCxFsCF/XH0yJ887y52kIHgbpLnIqTaM+2OMCbzf30cDW8mDk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1742212583; c=relaxed/simple; bh=Rkw4yJGSe21TTCcFB1UVx47FOz4c7u0YapVBfQVN8JI=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=Cnv1wRmuOkSjzFYCJpQRxKBUPG1n4puBwy464d7UqBzy2EoicWCAipLIZxGC1q9/gSXafKfFXobIFCE/4Z3evhp2AFf3WnUlxtjmtGXvdLVAFg1+/r/IsnjpgGzqt29x4Onc32ZNi0Vl0ai9fLMQ+a5F3MgZ+1P5H6fwRVXbHC8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linaro.org; spf=pass smtp.mailfrom=linaro.org; dkim=pass (2048-bit key) header.d=linaro.org header.i=@linaro.org header.b=GAFuxf8k; arc=none smtp.client-ip=209.85.218.45 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linaro.org Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linaro.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=linaro.org header.i=@linaro.org header.b="GAFuxf8k" Received: by mail-ej1-f45.google.com with SMTP id a640c23a62f3a-abec8b750ebso795727166b.0 for ; Mon, 17 Mar 2025 04:56:20 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; t=1742212579; x=1742817379; darn=vger.kernel.org; h=content-transfer-encoding:in-reply-to:from:content-language :references:cc:to:subject:user-agent:mime-version:date:message-id :from:to:cc:subject:date:message-id:reply-to; bh=nvSmeQlqS0PVSiztlrJp1EnapLR9YnzwoX8WjGMczkU=; b=GAFuxf8khfL58+1sCmYA3BoL1lWWLoKhdWuiDa3WwW7NW3SV+BlG/saX2l5oetXEhr I4isjl10fRfSx8Ni3V86LVKeJTk8HxxraFgZ9L0YZK4TlJjBCpoFIPla6Dy0r1u8mLB9 Pb/hyl7VVeXuApQWh3CPqAcHh0UDvRAIG42a6E/QLP1qnqTaht4/O20rG7iITz+kkO4x bLnXnZVqhKuVkKZq3BABxJJ6TZi2rUzC/YY2x1ghiIYxB4I3/L0eahbVXDOY4Zq7IT5f B0umlTWey96yaU43HTYn/tbC86F5ISC0G9B602CmYEny8O+kNq0+Y7SadwYaZJdyDTtv oI9A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1742212579; x=1742817379; h=content-transfer-encoding:in-reply-to:from:content-language :references:cc:to:subject:user-agent:mime-version:date:message-id :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=nvSmeQlqS0PVSiztlrJp1EnapLR9YnzwoX8WjGMczkU=; b=m0F0CHzud3HSw3m8yBmL3svzLXlczf2Mr3STe/nbArVdcj75elP+EpW+X/C+oeBp9D vBrN22NG/Rt96raoOG1GE0SdWGj/5sQ3oIfg+R8UybN3VIJT13JbTQH/78357/6OtbJa tK7PgrPAeXeBmwKAa32+fcTI0y8SCKWOtSsOReZOsIlSzEpCuxqBIdEWTLirY6u//eqF mK9CsSvv7Hak+L/7ADfKMvBBFVu3Mb889EjfCt888gMh6DFfYbc2cot4iDuh4TM/17zJ Y9T3w+Iogof5WrubNKUyLdUorecfCQLs3yAekNCiJMdKd1VsXnP9dJhLZ1ps5tzl3J77 CCrQ== X-Forwarded-Encrypted: i=1; AJvYcCUBtzcVDjuQZ0CvjrBdpIbLb410rjbdr7KHPOjbMCIYOIo3MtQ3+vdoE1YVs5gmu3CwhOBw5ur3OLkJvL8=@vger.kernel.org X-Gm-Message-State: AOJu0YyMb+YegNCbqACCQuBORCzN8jQsRIz4ASJf5jNQ7zVvBvph1GjE /XzVLqpjOleMdfmu2webWJt1XKsO9II/GF9F+oeJGUeO+HhC6iWkC18Xce9GPB8= X-Gm-Gg: ASbGnctjZr21IXpVuSLAi1AJZj7Q+n1gqCeXcZ4z4h/oJv5/OUh2KKJhvXRiHTzuSLH jlDzRenT58/h8I15m+9ZlxxHLctGPlN81UlhtbVH31avj/JNDoXDCzkiQ35xoQnLU8UPdQAPDZs 1Upy5EnHXfgrtgX64OmntBkcfiMrrY5oiwkN50DWFWFnaB85o1AHZnuD0l/9VjI7K+p6uDcEEG7 lYDJTvsq9+uS8Ap3cnVxx+fBF6sxqfVg5ZmbT/LM+F85Wp8Mwsd96hdIuJ/JTg2lZK0KJluCvjc vpy8kpmXVbn0QSWZlxEOpqefqHmAMYRf60T+J6lEAplGgTTgW/saxA== X-Google-Smtp-Source: AGHT+IElqC4N7WBdN/UwREha3sJL0AOI9i9gOEBfGevhPlzqhMr3fPOn8XBHjesPAtYa3nhFewNk9Q== X-Received: by 2002:a17:907:a089:b0:ac1:ea39:9b9f with SMTP id a640c23a62f3a-ac330461ce4mr1164128466b.54.1742212579456; Mon, 17 Mar 2025 04:56:19 -0700 (PDT) Received: from [192.168.1.247] ([145.224.67.123]) by smtp.gmail.com with ESMTPSA id a640c23a62f3a-ac314a3e0e4sm657815566b.136.2025.03.17.04.56.18 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 17 Mar 2025 04:56:19 -0700 (PDT) Message-ID: Date: Mon, 17 Mar 2025 11:56:17 +0000 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 4/7] coresight: Add claim tag warnings and debug messages To: Leo Yan Cc: lcherian@marvell.com, coresight@lists.linaro.org, Mike Leach , Alexander Shishkin , Maxime Coquelin , Alexandre Torgue , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-stm32@st-md-mailman.stormreply.com References: <20250211103945.967495-1-james.clark@linaro.org> <20250211103945.967495-5-james.clark@linaro.org> <20250313144005.GQ9682@e132581.arm.com> Content-Language: en-US From: James Clark In-Reply-To: <20250313144005.GQ9682@e132581.arm.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 13/03/2025 2:40 pm, Leo Yan wrote: > On Tue, Feb 11, 2025 at 10:39:40AM +0000, James Clark wrote: >> >> Add a dev_dbg() message so that external debugger conflicts are more >> visible. There are multiple reasons for -EBUSY so a message for this >> particular one could be helpful. Add errors for and enumerate all the >> other cases that are impossible. >> >> Signed-off-by: James Clark >> --- >> drivers/hwtracing/coresight/coresight-core.c | 48 ++++++++++++-------- >> drivers/hwtracing/coresight/coresight-priv.h | 5 +- >> 2 files changed, 34 insertions(+), 19 deletions(-) >> >> diff --git a/drivers/hwtracing/coresight/coresight-core.c b/drivers/hwtracing/coresight/coresight-core.c >> index 7b53165c93af..7fe5d5d432c4 100644 >> --- a/drivers/hwtracing/coresight/coresight-core.c >> +++ b/drivers/hwtracing/coresight/coresight-core.c >> @@ -133,16 +133,6 @@ static inline u32 coresight_read_claim_tags(struct csdev_access *csa) >> csdev_access_relaxed_read32(csa, CORESIGHT_CLAIMCLR)); >> } >> >> -static inline bool coresight_is_claimed_self_hosted(struct csdev_access *csa) >> -{ >> - return coresight_read_claim_tags(csa) == CORESIGHT_CLAIM_SELF_HOSTED; >> -} >> - >> -static inline bool coresight_is_claimed_any(struct coresight_device *csdev) >> -{ >> - return coresight_read_claim_tags(&csdev->access) != 0; >> -} >> - >> static inline void coresight_set_self_claim_tag(struct csdev_access *csa) >> { >> csdev_access_relaxed_write32(csa, CORESIGHT_CLAIM_SELF_HOSTED, >> @@ -169,18 +159,40 @@ static inline void coresight_clear_self_claim_tag(struct csdev_access *csa) >> */ >> int coresight_claim_device_unlocked(struct coresight_device *csdev) >> { >> + int tag; >> + struct csdev_access *csa; >> + >> if (WARN_ON(!csdev)) >> return -EINVAL; >> >> - if (coresight_is_claimed_any(csdev)) >> + csa = &csdev->access; >> + tag = coresight_read_claim_tags(csa); >> + >> + switch (tag) { >> + case CORESIGHT_CLAIM_FREE: >> + coresight_set_self_claim_tag(csa); >> + if (coresight_read_claim_tags(csa) == CORESIGHT_CLAIM_SELF_HOSTED) >> + return 0; >> + > > It would be a rare case if a failure happens here. Seems to me, it > would be valuable to print a log for this edge case. > > Otherwise, looks good to me. > Yeah I can add dev_dbg("Busy: Couldn't set self claim tag"). Just to distinguish this race case from the other busy case.