Hi Bagas,
On Wed, 21 Dec 2022 at 03:55, Bagas Sanjaya bagasdotme@gmail.com wrote:
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.
The next version will contain all the adjustments that you suggested, though rather than using single quotes, I have changed all the occurrences to consistently the double back tick to make the filenames etc fixed width font.
Thanks for the review
Mike
Thanks.
-- An old man doll... just what I always wanted! - Clara
-- Mike Leach Principal Engineer, ARM Ltd. Manchester Design Centre. UK
-
Mike Leach