[PATCH v1 1/9] perf pmu: Add documentation

[Ian Rogers <irogers@google.com>]

Add documentation to struct perf_pmu and the associated structs of
perf_pmu_alias and perf_pmu_format.

Signed-off-by: Ian Rogers <irogers@google.com>
---
 tools/perf/util/pmu.c |  14 ++++++
 tools/perf/util/pmu.h | 105 +++++++++++++++++++++++++++++++++++++++---
 2 files changed, 113 insertions(+), 6 deletions(-)

diff --git a/tools/perf/util/pmu.c b/tools/perf/util/pmu.c
index 6a86e6af0903..a8f9f47c6ed9 100644
--- a/tools/perf/util/pmu.c
+++ b/tools/perf/util/pmu.c
@@ -31,10 +31,24 @@
 
 struct perf_pmu perf_pmu__fake;
 
+/**
+ * Values from a format file read from <sysfs>/devices/cpu/format/ held in
+ * struct perf_pmu. For example, the contents of
+ * <sysfs>/devices/cpu/format/event may be "config:0-7" and will be represented
+ * here as name="event", value=PERF_PMU_FORMAT_VALUE_CONFIG and bits 0 to 7 will
+ * be set.
+ */
 struct perf_pmu_format {
+	/** The modifier/file name. */
 	char *name;
+	/**
+	 * Which config value the format relates to. Supported values are from
+	 * PERF_PMU_FORMAT_VALUE_CONFIG to PERF_PMU_FORMAT_VALUE_CONFIG_END.
+	 */
 	int value;
+	/** Which config bits are set by this format value. */
 	DECLARE_BITMAP(bits, PERF_PMU_FORMAT_BITS);
+	/** Element on list within struct perf_pmu. */
 	struct list_head list;
 };
 
diff --git a/tools/perf/util/pmu.h b/tools/perf/util/pmu.h
index 68e15c38ae71..29571c0f9d15 100644
--- a/tools/perf/util/pmu.h
+++ b/tools/perf/util/pmu.h
@@ -34,30 +34,91 @@ struct perf_pmu_caps {
 };
 
 struct perf_pmu {
+	/** The name of the PMU such as "cpu". */
 	char *name;
+	/**
+	 * Optional alternate name for the PMU determined in architecture
+	 * specific code.
+	 */
 	char *alias_name;
+	/**
+	 * Optional PMU identifier read from
+	 * <sysfs>/bus/event_source/devices/<name>/identifier.
+	 */
 	char *id;
+	/**
+	 * Perf event attributed type value, read from
+	 * <sysfs>/bus/event_source/devices/<name>/type.
+	 */
 	__u32 type;
+	/**
+	 * Can the PMU name be selected as if it were an event?
+	 */
 	bool selectable;
+	/**
+	 * Is the PMU not within the CPU core? Determined by the presence of
+	 * <sysfs>/bus/event_source/devices/<name>/cpumask.
+	 */
 	bool is_uncore;
+	/** Is the PMU name either cpu_core or cpu_atom. */
 	bool is_hybrid;
+	/**
+	 * Are events auxiliary events? Determined in architecture specific
+	 * code.
+	 */
 	bool auxtrace;
+	/**
+	 * Number of levels of :ppp precision supported by the PMU, read from
+	 * <sysfs>/bus/event_source/devices/<name>/caps/max_precise.
+	 */
 	int max_precise;
+	/**
+	 * Optional default perf_event_attr determined in architecture specific
+	 * code.
+	 */
 	struct perf_event_attr *default_config;
+	/**
+	 * Empty or the contents of either of:
+	 * <sysfs>/bus/event_source/devices/<name>/cpumask.
+	 * <sysfs>/bus/event_source/devices/<cpu>/cpus.
+	 */
 	struct perf_cpu_map *cpus;
-	struct list_head format;  /* HEAD struct perf_pmu_format -> list */
-	struct list_head aliases; /* HEAD struct perf_pmu_alias -> list */
+	/**
+	 * Holds the contents of files read from
+	 * <sysfs>/bus/event_source/devices/<name>/format/. The contents specify
+	 * which event parameter changes what config, config1 or config2 bits.
+	 */
+	struct list_head format;
+	/**
+	 * List of struct perf_pmu_alias. Each alias corresponds to an event
+	 * read from <sysfs>/bus/event_source/devices/<name>/events/ or from
+	 * json events in pmu-events.c.
+	 */
+	struct list_head aliases;
+	/** Has the list caps been initialized? */
 	bool caps_initialized;
+	/** The length of the list caps. */
 	u32 nr_caps;
-	struct list_head caps;    /* HEAD struct perf_pmu_caps -> list */
-	struct list_head list;    /* ELEM */
+	/**
+	 * Holds the contents of files read from
+	 * <sysfs>/bus/event_source/devices/<name>/caps/. The contents are pairs
+	 * of the filename with the value of its contents, for example,
+	 * max_precise (see above) may have a value of 3.
+	 */
+	struct list_head caps;
+	/** Element on pmus list in pmu.c. */
+	struct list_head list;
+	/** Element on perf_pmu__hybrid_pmus. */
 	struct list_head hybrid_list;
 
+	/** Features to inhibit when events on this PMU are opened. */
 	struct {
+		/** Disables perf_event_attr exclude_guest and exclude_host. */
 		bool exclude_guest;
 	} missing_features;
 };
 
+/** A special global PMU used for testing. */
 extern struct perf_pmu perf_pmu__fake;
 
 struct perf_pmu_info {
@@ -71,21 +132,53 @@ struct perf_pmu_info {
 
 #define UNIT_MAX_LEN	31 /* max length for event unit name */
 
+/**
+ * An event either read from sysfs or builtin in pmu-events.c, created by
+ * parsing the pmu-events json files.
+ */
 struct perf_pmu_alias {
 	char *name;
+	/** Optional short description of the event. */
 	char *desc;
+	/** Optional long description. */
 	char *long_desc;
+	/**
+	 * Optional topic such as cache or pipeline, particularly for json
+	 * events.
+	 */
 	char *topic;
+	/** Comma separated parameter list. */
 	char *str;
-	struct list_head terms; /* HEAD struct parse_events_term -> list */
-	struct list_head list;  /* ELEM */
+	/** Owned list of the original parsed parameters. */
+	struct list_head terms;
+	/** List element of struct perf_pmu aliases. */
+	struct list_head list;
+	/** Units for the event, such as bytes or cache lines. */
 	char unit[UNIT_MAX_LEN+1];
+	/** Value to scale read counter values by. */
 	double scale;
+	/**
+	 * Does the file
+	 * <sysfs>/bus/event_source/devices/<pmu_name>/events/<name>.per-pkg or
+	 * equivalent json value exist and have the value 1.
+	 */
 	bool per_pkg;
+	/**
+	 * Does the file
+	 * <sysfs>/bus/event_source/devices/<pmu_name>/events/<name>.snapshot
+	 * exist and have the value 1.
+	 */
 	bool snapshot;
+	/** Is the event hidden and so not shown in perf list by default. */
 	bool deprecated;
+	/**
+	 * A metric expression associated with an event. Doing this makes little
+	 * sense due to scale and unit applying to both.
+	 */
 	char *metric_expr;
+	/** A name for the metric. unit applying to both. */
 	char *metric_name;
+	/** The name copied from struct perf_pmu. */
 	char *pmu_name;
 };
 
-- 
2.38.1.431.g37b22c650d-goog