From nobody Wed Sep 17 12:04:47 2025 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 C78FCC4332F for ; Mon, 19 Dec 2022 23:47:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229802AbiLSXrR (ORCPT ); Mon, 19 Dec 2022 18:47:17 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45214 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232694AbiLSXqy (ORCPT ); Mon, 19 Dec 2022 18:46:54 -0500 Received: from mail-wr1-x430.google.com (mail-wr1-x430.google.com [IPv6:2a00:1450:4864:20::430]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E37FC1114E for ; Mon, 19 Dec 2022 15:46:50 -0800 (PST) Received: by mail-wr1-x430.google.com with SMTP id h12so10200820wrv.10 for ; Mon, 19 Dec 2022 15:46:50 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=references:in-reply-to:message-id:date:subject:cc:to:from:from:to :cc:subject:date:message-id:reply-to; bh=20URghUEhnd48vVWNIo4NcdPqwWP3OApoVFQSqBizbk=; b=XrGsIL3zLIGiSSn6zRwToocscYx+EVhRGz0v2L1n/IAjuMcU6xq8ZxA2Wus2Ht6e9N S6C2+S60mmYaom7yAsckD8S25Ejvvcqe3F3SJmBbvSPaiKxrPfxWn9DTSgnKDa/+OqNl mc9TLU7w9ovr7ziKMBo0UqNMEtE4C3eOa0PQJvlkSW0u6trdiuySdE8p/gNE/utvkkou YxAZ+G9dzZdfS0bdLiNYmdOvHB6TpFNjqgitjPcyn3NwIEffSny6Tyt0mxRN66OpK4TU YOkTfkTzLeC0IdVDj8ppUq80K+kQFcI4raWg7306COdxXtCPeDg+HudpqicpXG2aegSM bZDQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=references:in-reply-to:message-id:date:subject:cc:to:from :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=20URghUEhnd48vVWNIo4NcdPqwWP3OApoVFQSqBizbk=; b=WX7SLIRerOMbdhlnaBIGHqX8hcrmiE8uUnm71E10JlCLyyjD2lDzoydtBWmeReabyA +shHw8IESOPOm4ncDaSJbNhBibH0Gh608FPM8bXa9IxcdBlUz9brbIxjmXa5FE7B3eVq WQ74jfkpydi0luAKD0UYRv99t0jpTtD/5h8REWpSgf9+GNf6AemdtbZdJ8MDGfjTpuFP hMq+9HcAYMLoEjSlsyCFWYbiWeIhbGOLyurewag97WBKLJHIcMwprlg4TcFvq3HQFCne cVHTnHYdeKNsY+UQbWRUqGVMrzwkQkuESJJjj03DeboVk/qErDZscMwzsuGJvuMuowOY 6Vjg== X-Gm-Message-State: AFqh2kp+QcrbJKuwY40KYYrU3BwHqBNsleyLwq9CNJ+G9uZikL3Dgza8 4u1BRDOAllu5HVEa54oo9hshvg== X-Google-Smtp-Source: AMrXdXt6JZzeWZ/AtX+SAqVE7wKHSrEQFyPWiwpw8cD02387TMiFxduKOJlehH3NW+aKz7L7W5wBsQ== X-Received: by 2002:adf:dbc7:0:b0:25d:d243:4f3c with SMTP id e7-20020adfdbc7000000b0025dd2434f3cmr6508350wrj.69.1671493609382; Mon, 19 Dec 2022 15:46:49 -0800 (PST) Received: from linaro.org ([2a00:23c5:6809:2201:bce1:4a06:7ceb:6940]) by smtp.gmail.com with ESMTPSA id n2-20020a5d4c42000000b002383fc96509sm11165148wrt.47.2022.12.19.15.46.48 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 19 Dec 2022 15:46:48 -0800 (PST) From: Mike Leach To: linux-arm-kernel@lists.infradead.org, coresight@lists.linaro.org, linux-kernel@vger.kernel.org Cc: mathieu.poirier@linaro.org, suzuki.poulose@arm.com, acme@kernel.org, james.clark@arm.com, Mike Leach , Jonathan Corbet , linux-doc@vger.kernel.org Subject: [PATCH v5 6/6] Documentation: coresight: docs for config load via configfs Date: Mon, 19 Dec 2022 23:46:38 +0000 Message-Id: <20221219234638.3661-7-mike.leach@linaro.org> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20221219234638.3661-1-mike.leach@linaro.org> References: <20221219234638.3661-1-mike.leach@linaro.org> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Add documentation covering the configfs updates that allow binary configuration files to be loaded and unloaded via configfs, along with the demonstration programs in samples. Cc: Jonathan Corbet Cc: linux-doc@vger.kernel.org Signed-off-by: Mike Leach --- .../trace/coresight/coresight-config.rst | 202 +++++++++++++++++- 1 file changed, 195 insertions(+), 7 deletions(-) diff --git a/Documentation/trace/coresight/coresight-config.rst b/Documenta= tion/trace/coresight/coresight-config.rst index 6d5ffa6f7347..109053eb1b93 100644 --- a/Documentation/trace/coresight/coresight-config.rst +++ b/Documentation/trace/coresight/coresight-config.rst @@ -141,11 +141,11 @@ Mount configfs as normal and the 'cs-syscfg' subsyste= m will appear:: $ ls /config cs-syscfg stp-policy =20 -This has two sub-directories:: +This has two sub-directories, with the load and unload attribute files:: =20 $ cd cs-syscfg/ $ ls - configurations features + configurations features load unload =20 The system has the configuration 'autofdo' built in. It may be examined as follows:: @@ -278,9 +278,16 @@ Creating and Loading Custom Configurations =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D =20 Custom configurations and / or features can be dynamically loaded into the -system by using a loadable module. +system by using a loadable module, or by loading a binary configuration +file in configfs. =20 -An example of a custom configuration is found in ./samples/coresight. +Loaded configurations can use previously loaded features. The system will +ensure that it is not possible to unload a feature that is currently in +use, by enforcing the unload order as the strict reverse of the load order. + + +Using a Loadable Module +----------------------- =20 This creates a new configuration that uses the existing built in strobing feature, but provides a different set of presets. @@ -289,6 +296,187 @@ When the module is loaded, then the configuration app= ears in the configfs file system and is selectable in the same way as the built in configuration described above. =20 -Configurations can use previously loaded features. The system will ensure -that it is not possible to unload a feature that is currently in use, by -enforcing the unload order as the strict reverse of the load order. +The file 'coresight-cfg-sample.c' contains the configuration and module +initialisation code needed to create the loadable module. + +This will be built alongside the kernel modules if select in KConfig. + +An example of a custom configuration module is found in './samples/coresig= ht'. + +Using a Binary Configuration File +--------------------------------- + +The './tools/coresight' directory contains example programs to generate and +read and print binary configuration files. + +Building the tools creates the 'coresight-cfg-file-gen' program that will +generate a configuration binary 'example1.cscfg' that can be loaded into t= he +system using configfs. The configuration declared in the source file +'coresight-cfg-example1.c' is named 'autofdo3' - the name that will be used +once loaded. + +The source files 'coresight-cfg-bufw.h' and 'coresight-cfg-bufw.c' provide= a +standard function to convert a configuration declared in 'C' into the corr= ect +binary buffer format. These files can be re-used to create new custom +configurations. Alternatively, addition examples can be added to the +'coresight-cfg-file-gen' program:: + + $ ./coresight-cfg-file-gen + Coresight Configuration file Generator + + Generating example1 example + Generating example2 example + +The program 'coresight-cfg-file-read' can read back and print a configurat= ion +binary. This is built using the file reader from the driver code +(coresight-config-file.c), which is copied over into './tools/coresight' at +build time.:: + + ./coresight-cfg-file-read example1.cscfg + CoreSight Configuration file reader + =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D + + Configuration 1 + Name:- autofdo3 + Description:- + Setup ETMs with strobing for autofdo + Supplied presets allow experimentation with mark-space ratio for vario= us loads + + Uses 1 features:- + Feature-1: strobing + + Provides 4 sets of preset values, 2 presets per set + set[0]: 0x7d0, 0x64, + set[1]: 0x7d0, 0x3e8, + set[2]: 0x7d0, 0x1388, + set[3]: 0x7d0, 0x2710, + + =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D + File contains no features + +There are additional attributes in the cs-syscfg directory - load and +unload that can be used to load and unload configuration binary files. To +load, 'cat' the binary config into the load attribute:: + + $ ls /config/cs-syscfg + configurations features load unload + $ cat example1.cscfg > /config/cs-syscfg/load + $ ls /config/cs-syscfg/configurations/ + autofdo autofdo3 + +To unload, use the same file in the unload attribute:: + + $ cat example1.cscfg > /config/cs-syscfg/unload + ls /config/cs-syscfg/configurations/ + autofdo + + + +Binary Configuration File Format +-------------------------------- + +The file format is defined in the source file **coresight-config-file.h** + +The source reader and generator examples produce a binary of this format. + +This arrangement is reproduced below:- + +Overall File structure +~~~~~~~~~~~~~~~~~~~~~~ + +:: + + [cscfg_file_header] // Mandatory + [CONFIG_ELEM]* // Optional - multiple, defined by cscfg_file_hea= der.nr_configs + [FEATURE_ELEM]* // Optional - multiple, defined by cscfg_file_hea= der.nr_features + +File is invalid if both [CONFIG_ELEM] and [FEATURE_ELEM] are omitted. + +A file that contains only [FEATURE_ELEM] may be loaded, and the features u= sed +by subsequently loaded files with [CONFIG_ELEM] elements. + +Element Name Strings +~~~~~~~~~~~~~~~~~~~~ + +Configuration name strings are required to consist of alphanumeric charact= ers and '_' only. Other special characters are not permitted. + +:: + my_config_2 // is a valid name. + this-bad-config#5 // this will not work + +This is in order to comply with the requirements of the perf command line. + +It is recommended that Feature and Parameter names use the same convention= to allow for future enhancements to the command line syntax. + +CONFIG_ELEM element +~~~~~~~~~~~~~~~~~~~ + +:: + + [cscfg_file_elem_header] // header length value to end o= f feature strings. + [cscfg_file_elem_str] // name of the configuration. + // (see element string name req= uirements) + [cscfg_file_elem_str] // description of configuration. + [u16 value](nr_presets) // number of defined sets prese= ts values. + [u32 value](nr_total_params) // total parameters defined by = all used features. + [u16 value](nr_feat_refs) // number of features reference= d by the configuration + [u64 values] * (nr_presets * nr_total_params) // the preset values. + [cscfg_file_elem_str] * (nr_feat_refs) // names of features used in th= e configurations. + +FEATURE_ELEM element +~~~~~~~~~~~~~~~~~~~~ + +:: + + [cscfg_file_elem_header] // header length is total bytes= to end of param structures. + [cscfg_file_elem_str] // feature name. + [cscfg_file_elem_str] // feature description. + [u32 value](match_flags) // flags to associate the featu= re with a device. + [u16 value](nr_regs) // number of registers. + [u16 value](nr_params) // number of parameters. + [cscfg_regval_desc struct] * (nr_regs) // register definitions + [PARAM_ELEM] * (nr_params) // parameters definitions + +PARAM_ELEM element +~~~~~~~~~~~~~~~~~~ + +:: + + [cscfg_file_elem_str] // parameter name. + [u64 value](param_value) // initial value. + +Additional definitions. +~~~~~~~~~~~~~~~~~~~~~~~ + +The following structures are defined in **coresight-config-file.h** + + * **struct cscfg_file_header** : This structure contains an initial magic= number, the total + length of the file, and the number of configurations and features in th= e file. + * **struct cscfg_file_elem_header**: This defines the total length and ty= pe of a CONFIG_ELEM + or a FEATURE_ELEM. + * **struct cscfg_file_elem_str**: This defines a string and its length. + +The magic number in cscfg_file_header is defined as two bitfields:: + + [31:8] Fixed magic number to identify file type. + [7:0] Current file format version. + +The following defines determine the maximum overall file size and maximum = individual +string size:: + + CSCFG_FILE_MAXSIZE // maximum overall file size. + CSCFG_FILE_STR_MAXSIZE // maximum individual string size. + +Load Dependencies. +~~~~~~~~~~~~~~~~~~ + +Files may be unloaded only in the strict reverse order of loading. This is= enforced by the +configuration system. + +This is to ensure that any load dependencies are maintained. + +A configuration file that contains a CONFIG_ELEM that references named fea= tures "feat_A" and "feat_B" will load only if either:- +a) "feat_A" and/or "feat_B" has been loaded previously, or are present as = built-in / module loaded features. +b) "feat_A" and/or "feat_B" are declared as FEAT_ELEM in the same file as = the CONFIG_ELEM. + +Files that contain features or configurations with the same names as those= already loaded will fail to load. --=20 2.17.1