Merge tag 'coresight-next-v5.17' of...

    autofdo

    $ cd autofdo/

    $ ls

    description   preset1  preset3  preset5  preset7  preset9

    feature_refs  preset2  preset4  preset6  preset8

    description  feature_refs  preset1  preset3  preset5  preset7  preset9

    enable       preset        preset2  preset4  preset6  preset8

    $ cat description

    Setup ETMs with strobing for autofdo

    $ cat feature_refs

    strobing

Each preset declared has a preset<n> subdirectory declared. The values for

Each preset declared has a 'preset<n>' subdirectory declared. The values for

the preset can be examined::

    $ cat preset1/values

    $ cat preset2/values

    strobing.window = 0x1388 strobing.period = 0x4

The 'enable' and 'preset' files allow the control of a configuration when

using CoreSight with sysfs.

The features referenced by the configuration can be examined in the features

directory::

be selected when running trace under perf::

    $ ls /sys/devices/cs_etm

    configurations  format  perf_event_mux_interval_ms  sinks  type

    events  nr_addr_filters  power

Key directories here are 'configurations' - which lists the loaded

configurations, and 'events' - a generic perf directory which allows

selection on the perf command line.::

    cpu0  cpu2  events  nr_addr_filters		power  subsystem  uevent

    cpu1  cpu3  format  perf_event_mux_interval_ms	sinks  type

    $ ls configurations/

    autofdo

    $ cat configurations/autofdo

    0xa7c3dddd

The key directory here is 'events' - a generic perf directory which allows

selection on the perf command line. As with the sinks entries, this provides

a hash of the configuration name.

As with the sinks entries, this provides a hash of the configuration name.

The entry in the 'events' directory uses perfs built in syntax generator

to substitute the syntax for the name when evaluating the command::

When configurations are selected in this way, then the trace sink used is

automatically selected.

Using Configurations in sysfs

=============================

Coresight can be controlled using sysfs. When this is in use then a configuration

can be made active for the devices that are used in the sysfs session.

In a configuration there are 'enable' and 'preset' files.

To enable a configuration for use with sysfs::

    $ cd configurations/autofdo

    $ echo 1 > enable

This will then use any default parameter values in the features - which can be

adjusted as described above.

To use a preset<n> set of parameter values::

    $ echo 3 > preset

This will select preset3 for the configuration.

The valid values for preset are 0 - to deselect presets, and any value of

<n> where a preset<n> sub-directory is present.

Note that the active sysfs configuration is a global parameter, therefore

only a single configuration can be active for sysfs at any one time.

Attempting to enable a second configuration will result in an error.

Additionally, attempting to disable the configuration while in use will

also result in an error.

The use of the active configuration by sysfs is independent of the configuration

used in perf.

Creating and Loading Custom Configurations

==========================================

Custom configurations and / or features can be dynamically loaded into the

system by using a loadable module.

An example of a custom configuration is found in ./samples/coresight.

This creates a new configuration that uses the existing built in

strobing feature, but provides a different set of presets.

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.

F:	drivers/hwtracing/coresight/*

F:	include/dt-bindings/arm/coresight-cti-dt.h

F:	include/linux/coresight*

F:	samples/coresight/*

F:	tools/perf/arch/arm/util/auxtrace.c

F:	tools/perf/arch/arm/util/cs-etm.c

F:	tools/perf/arch/arm/util/cs-etm.h

	NULL

};

static struct cscfg_load_owner_info preload_owner = {

	.type = CSCFG_OWNER_PRELOAD,

};

/* preload called on initialisation */

int cscfg_preload(void)

int cscfg_preload(void *owner_handle)

{

	return cscfg_load_config_sets(preload_cfgs, preload_feats);

	preload_owner.owner_handle = owner_handle;

	return cscfg_load_config_sets(preload_cfgs, preload_feats, &preload_owner);

}

 * @params_desc: array of parameters used.

 * @nr_regs:	 number of registers used.

 * @regs_desc:	 array of registers used.

 * @load_owner:	 handle to load owner for dynamic load and unload of features.

 * @fs_group:	 reference to configfs group for dynamic unload.

 */

struct cscfg_feature_desc {

	const char *name;

	struct cscfg_parameter_desc *params_desc;

	int nr_regs;

	struct cscfg_regval_desc *regs_desc;

	void *load_owner;

	struct config_group *fs_group;

};

/**

 * @presets:		Array of preset values.

 * @event_ea:		Extended attribute for perf event value

 * @active_cnt:		ref count for activate on this configuration.

 *

 * @load_owner:		handle to load owner for dynamic load and unload of configs.

 * @fs_group:		reference to configfs group for dynamic unload.

 */

struct cscfg_config_desc {

	const char *name;

	const u64 *presets; /* nr_presets * nr_total_params */

	struct dev_ext_attribute *event_ea;

	atomic_t active_cnt;

	void *load_owner;

	struct config_group *fs_group;

};

/**

 * coresight_grab_device - Power up this device and any of the helper

 * devices connected to it for trace operation. Since the helper devices

 * don't appear on the trace path, they should be handled along with the

 * the master device.

 * master device.

 */

static int coresight_grab_device(struct coresight_device *csdev)

{