coresight: introducing a global trace ID function
TraceID values have to be unique for all tracers and
consistent between drivers and user space. As such
introducing a central function to be used whenever a
traceID value is required.
The patch also account for data traceIDs, which are usually
I(N) + 1.
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/include/linux/coresight-pmu.h b/include/linux/coresight-pmu.h
index 6c5386b..7d41026 100644
--- a/include/linux/coresight-pmu.h
+++ b/include/linux/coresight-pmu.h
@@ -19,9 +19,21 @@
#define _LINUX_CORESIGHT_PMU_H
#define CORESIGHT_ETM_PMU_NAME "cs_etm"
+#define CORESIGHT_ETM_PMU_SEED 0x10
/* ETMv3.5/PTM's ETMCR config bit */
#define ETM_OPT_CYCACC 12
#define ETM_OPT_TS 28
+static inline int coresight_get_trace_id(int cpu)
+{
+ /*
+ * A trace ID of value 0 is invalid, so let's start at some
+ * random value that fits in 7 bits and go from there. Since
+ * the common convention is to have data trace IDs be I(N) + 1,
+ * set instruction trace IDs as a function of the CPU number.
+ */
+ return (CORESIGHT_ETM_PMU_SEED + (cpu * 2));
+}
+
#endif