From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1) server-digest SHA256) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 60288606A31A for ; Wed, 21 Oct 2026 14:40:15 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key, unprotected) header.d=lists.infradead.org header.i=@lists.infradead.org header.a=rsa-sha256 header.s=bombadil.20210309 header.b=oz5SjpFl; dkim=pass (1024-bit key, unprotected) header.d=arm.com header.i=@arm.com header.a=rsa-sha256 header.s=foss header.b=hjQkMejx DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=1m78tWGGeDJIH1O9K2lE2ESdNUNdQQcLVxQs2dYVHn4=; b=oz5SjpFl3Nti4GaSgVkICNqXMe dFD6rdKyXq80ACFADpUhT9YRWgn3DgcJ0SUCVAkISo/htw+xcEe+bp6hAPYk90ADHYohMqIHhIpAO K31PaMxDomIJZoaVJB1kQBRiNKaSVvOJFy8LRbeI08sUhjI7tCMgspUSx9Hgju3gamOOtXl0fzQpO 4SCxKFUhAm4fz6rhLiPz8KwvseZeL71MEN6hfjkAGq6rrV//hVaa2hkfEELLC2nH9pwCDhMzTZedI U0fNx39syFaWyg8Cc8/MXeCvRmC54+KhmYrmHiW6LtpEzvM74tdq5fS8QNiW/JsDOLTj5nT24OCKv bsKcD4dA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.99.1 #2 (Red Hat Linux)) id 1xJXU6-0000000C7ew-1ATI; Wed, 21 Oct 2026 14:40:06 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.99.1 #2 (Red Hat Linux)) id 1xJXU3-0000000C7eT-3dDM for linux-arm-kernel@lists.infradead.org; Wed, 21 Oct 2026 14:40:05 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id D2D3B2880; Wed, 21 Oct 2026 07:39:57 -0700 (PDT) Received: from localhost (unknown [10.2.196.114]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id B01FF3F7D8; Wed, 21 Oct 2026 07:40:00 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=arm.com; s=foss; t=1792593601; bh=QRNpGsebJ+fw8gymcaKJxQJyRKlhooI9CG4j2vpkYXY=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=hjQkMejxD6ErdyhS8yadWEEQeMWR2Tjn9W52QMOWm+Ng9DG6zxtgT5xsnwpiaMU+f 3pnKhlIsV15kzsr17226O0yToPuV0g6AvFm+R/UCoWlVjKY3sXLMtD4nkEJ02/VDLP vF9VO3y/nOTKObHpp+Wn30wEtpCELCWIvd2sO42I= Date: Wed, 21 Oct 2026 15:39:58 +0100 From: Leo Yan To: Amir Ayupov Cc: James Clark , Suzuki K Poulose , Mike Leach , Alexander Shishkin , Jonathan Corbet , Randy Dunlap , Shuah Khan , coresight@lists.linaro.org, linux-arm-kernel@lists.infradead.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2 2/4] coresight: syscfg: Match feature capabilities separately from device class Message-ID: <20261021143958.GH26205@e132581.arm.com> References: <20261012230527.750567-1-aaupov@fb.com> <20261012230527.750567-3-aaupov@fb.com> X-Archived-By: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20261012230527.750567-3-aaupov@fb.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.9.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20261021_074004_037463_4A2916CF X-CRM114-Status: GOOD ( 16.85 ) X-Spam-Score: -4.4 (----) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" X-Spam-Status: No, score=-11.2 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=4.0.1 X-Spam-Checker-Version: SpamAssassin 4.0.1 (2024-03-26) on aws-us-west-2-korg-listserv-alma10-1 On Mon, Oct 12, 2026 at 04:05:21PM -0700, Amir Ayupov wrote: [...] > --- a/drivers/hwtracing/coresight/coresight-config.h > +++ b/drivers/hwtracing/coresight/coresight-config.h > @@ -30,6 +30,12 @@ > #define CS_CFG_MATCH_CLASS_SRC_ALL 0x0001 /* match any source */ > #define CS_CFG_MATCH_CLASS_SRC_ETM4 0x0002 /* match any ETMv4 device */ It is good to introduce a marco: #define CS_CFG_MATCH_CLASS_MASK GENMASK_U32(7, 0) > +/* > + * flags defining device capabilities a feature can require. A feature loads on > + * a device that matches one of its classes and has all of its capabilities. > + */ > +#define CS_CFG_MATCH_CAP_MASK 0x0000ff00 To make the mask explicitly 32-bit unsigned: #define CS_CFG_MATCH_CAP_MASK GENMASK_U32(15, 8) > + > /* flags defining device instance matching - used in config match desc data. */ > #define CS_CFG_MATCH_INST_ANY 0x80000000 /* any instance of a class */ Not an issue with this patch, but CS_CFG_MATCH_INST_ANY appears to be unused and could be removed in a separate cleanup patch. > diff --git a/drivers/hwtracing/coresight/coresight-syscfg.c b/drivers/hwtracing/coresight/coresight-syscfg.c > index a816c22c87bc8..1545d64afec01 100644 > --- a/drivers/hwtracing/coresight/coresight-syscfg.c > +++ b/drivers/hwtracing/coresight/coresight-syscfg.c > @@ -172,7 +172,21 @@ cscfg_alloc_csdev_feat(struct coresight_device *csdev, struct cscfg_feature_desc > } > > /* load one feature into one coresight device */ > +/* > + * A feature matches a device that shares one of its class flags and has all of > + * the capability flags it requires. > + */ > +static bool cscfg_match_feat_csdev(u32 feat_flags, u32 csdev_flags) > +{ > + u32 caps = feat_flags & CS_CFG_MATCH_CAP_MASK; > + > + return (feat_flags & csdev_flags & ~CS_CFG_MATCH_CAP_MASK) && > + (csdev_flags & caps) == caps; For clearer comparison conditions: /* Class type must be matches */ if ((feat_flags & CS_CFG_MATCH_CLASS_MASK) != (csdev_flags & CS_CFG_MATCH_CLASS_MASK) return false; /* No required capabilities miss from the device */ if (feat_flags & ~csdev_flags & CS_CFG_MATCH_CAP_MASK) return false; return true; Thanks, Leo