perf tools: Add coresight etm PMU record capabilities

Coresight ETMs are IP blocks used to perform HW assisted tracing on a
CPU core.  This patch introduce the required auxiliary API functions
allowing the perf core to interact with a tracer.

Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Acked-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: linux-arm-kernel@lists.infradead.org
Link: http://lkml.kernel.org/r/1474041004-13956-4-git-send-email-mathieu.poirier@linaro.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

1 files changed, 54 insertions, 0 deletions

diff --git a/tools/perf/arch/arm/util/auxtrace.c b/tools/perf/arch/arm/util/auxtrace.c
new file mode 100644
index 000000000000..8edf2cb71564
--- /dev/null
+++ b/tools/perf/arch/arm/util/auxtrace.c
@@ -0,0 +1,54 @@
+/*
+ * Copyright(C) 2015 Linaro Limited. All rights reserved.
+ * Author: Mathieu Poirier <mathieu.poirier@linaro.org>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 as published by
+ * the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <stdbool.h>
+#include <linux/coresight-pmu.h>
+
+#include "../../util/auxtrace.h"
+#include "../../util/evlist.h"
+#include "../../util/pmu.h"
+#include "cs-etm.h"
+
+struct auxtrace_record
+*auxtrace_record__init(struct perf_evlist *evlist, int *err)
+{
+	struct perf_pmu	*cs_etm_pmu;
+	struct perf_evsel *evsel;
+	bool found_etm = false;
+
+	cs_etm_pmu = perf_pmu__find(CORESIGHT_ETM_PMU_NAME);
+
+	if (evlist) {
+		evlist__for_each_entry(evlist, evsel) {
+			if (cs_etm_pmu &&
+			    evsel->attr.type == cs_etm_pmu->type)
+				found_etm = true;
+		}
+	}
+
+	if (found_etm)
+		return cs_etm_record_init(err);
+
+	/*
+	 * Clear 'err' even if we haven't found a cs_etm event - that way perf
+	 * record can still be used even if tracers aren't present.  The NULL
+	 * return value will take care of telling the infrastructure HW tracing
+	 * isn't available.
+	 */
+	*err = 0;
+	return NULL;
+}