On Mon, Dec 19, 2022 at 11:46:38PM +0000, Mike Leach wrote: > diff --git a/Documentation/trace/coresight/coresight-config.rst b/Documentation/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' subsystem will appear:: > $ ls /config > cs-syscfg stp-policy > > -This has two sub-directories:: > +This has two sub-directories, with the load and unload attribute files:: > > $ cd cs-syscfg/ > $ ls > - configurations features > + configurations features load unload > > The system has the configuration 'autofdo' built in. It may be examined as > follows:: > @@ -278,9 +278,16 @@ Creating and Loading Custom Configurations > ========================================== > > 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. > > -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 > +----------------------- > > 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 appears in the configfs > file system and is selectable in the same way as the built in configuration > described above. > > -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. What config options (CONFIG_) are required for above to work? > + > +An example of a custom configuration module is found in './samples/coresight'. > + > +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 the > +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 correct > +binary buffer format. These files can be re-used to create new custom > +configurations. Alternatively, addition examples can be added to the s/addition/additional/ > +'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 configuration > +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 > + ============================================ > + > + Configuration 1 > + Name:- autofdo3 > + Description:- > + Setup ETMs with strobing for autofdo > + Supplied presets allow experimentation with mark-space ratio for various 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, > + > + ============================================ > + 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** Use single-quote for identifier names for consistency here. > + > +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_header.nr_configs > + [FEATURE_ELEM]* // Optional - multiple, defined by cscfg_file_header.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 used > +by subsequently loaded files with [CONFIG_ELEM] elements. > + > +Element Name Strings > +~~~~~~~~~~~~~~~~~~~~ > + > +Configuration name strings are required to consist of alphanumeric characters and '_' only. Other special characters are not permitted. > + > +:: > + my_config_2 // is a valid name. > + this-bad-config#5 // this will not work Instead of using code-block for name examples, what about "... For example, foo_bar is a valid name where as foo-bar# is not."? > + > +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 of feature strings. > + [cscfg_file_elem_str] // name of the configuration. > + // (see element string name requirements) > + [cscfg_file_elem_str] // description of configuration. > + [u16 value](nr_presets) // number of defined sets presets values. > + [u32 value](nr_total_params) // total parameters defined by all used features. > + [u16 value](nr_feat_refs) // number of features referenced 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 the 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 feature 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. > +~~~~~~~~~~~~~~~~~~~~~~~ Trim trailing period for section names > + > +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 the file. > + * **struct cscfg_file_elem_header**: This defines the total length and type of a CONFIG_ELEM > + or a FEATURE_ELEM. > + * **struct cscfg_file_elem_str**: This defines a string and its length. Again, for consistency, wrap identifier names in single-quotes. > + > +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. For parameter lists in elements, use bullet lists instead. > + > +Load Dependencies. > +~~~~~~~~~~~~~~~~~~ Trim trailing period for section names. > + > +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 features "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. Separate the preceding paragraph and the list with a blank line in order for the list to be rendered as list. Thanks. -- An old man doll... just what I always wanted! - Clara
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