[PATCH] selftests: arm coresight: sysfsmode testing

[Linu Cherian <lcherian@marvell.com>]

Add sysfs mode selftest for ARM Coresight hardware tracer.

Signed-off-by: Linu Cherian <lcherian@marvell.com>
---
 .../drivers/hwtracing/coresight/Makefile      |   5 +
 .../hwtracing/coresight/sysfs_test_trace.sh   | 144 ++++++++++++++++++
 2 files changed, 149 insertions(+)
 create mode 100644 tools/testing/selftests/drivers/hwtracing/coresight/Makefile
 create mode 100755 tools/testing/selftests/drivers/hwtracing/coresight/sysfs_test_trace.sh

diff --git a/tools/testing/selftests/drivers/hwtracing/coresight/Makefile b/tools/testing/selftests/drivers/hwtracing/coresight/Makefile
new file mode 100644
index 000000000000..7dc68ae1c0a9
--- /dev/null
+++ b/tools/testing/selftests/drivers/hwtracing/coresight/Makefile
@@ -0,0 +1,5 @@
+# SPDX-License-Identifier: GPL-2.0
+
+TEST_PROGS = sysfs_test_trace.sh
+
+include ../../../lib.mk
diff --git a/tools/testing/selftests/drivers/hwtracing/coresight/sysfs_test_trace.sh b/tools/testing/selftests/drivers/hwtracing/coresight/sysfs_test_trace.sh
new file mode 100755
index 000000000000..0d6307fff1d2
--- /dev/null
+++ b/tools/testing/selftests/drivers/hwtracing/coresight/sysfs_test_trace.sh
@@ -0,0 +1,144 @@
+#!/bin/sh
+# SPDX-License-Identifier: GPL-2.0
+# Copyright (C) 2024 Marvell.
+
+# Test Arm CoreSight trace capture in sysfs mode
+# Based on tools/perf/tests/shell/test_arm_coresight.sh
+
+glb_err=0
+
+arm_cs_report() {
+	if [ $2 != 0 ]; then
+		echo "$1: FAIL"
+		glb_err=$2
+	else
+		echo "$1: PASS"
+	fi
+}
+
+is_device_sink() {
+	# If the node of "enable_sink" is existed under the device path, this
+	# means the device is a sink device.
+
+	if [ -e "$1/enable_sink" ]; then
+
+		return 0
+	else
+		return 1
+	fi
+}
+
+# Configure sink for buffer mode
+cfg_sink_buf_mode() {
+	sink_dev=$1
+	mode=$2
+	# Set buffer mode if supported
+	if [ -e "$sink_dev/buf_modes_available" ]; then
+		cat $sink_dev/buf_modes_available | grep -E -q $mode
+		if [ $? -eq 0 ]; then
+			echo $mode > $sink_dev/buf_mode_preferred
+			return 0
+		fi
+	fi
+
+	return 1
+}
+
+run_app() {
+
+	taskset -c $1 dd if=/dev/urandom  of=/dev/null bs=1M count=64
+}
+
+sysfs_trace() {
+	src_dev=$1
+	sink_dev=$2
+	cpu=$3
+
+	# Enable sink device
+	echo 1 > $sink_dev/enable_sink
+	# Enable source device
+	echo 1 > $src_dev/enable_source
+
+	# Run app to be traced
+	run_app $cpu
+
+	# Read back trace data
+	dd if=/dev/$sink_dev_name of=/tmp/tracedata
+
+	# Verify if read is successful
+	err=$?
+
+	# Disable source device
+	echo 0 > $src_dev/enable_source
+
+	# Diskable sink device
+	echo 0 > $sink_dev/enable_sink
+
+	arm_cs_report "CoreSight path testing (CPU$cpu -> $sink_dev_name)" $err
+}
+
+try_sysfs_trace_resrv_buf() {
+	src_dev=$1
+	sink_dev=$2
+	cpu=$3
+
+	# Configure the resrved buffer mode if available
+	cfg_sink_buf_mode $sink_dev "resrv"
+	if [ $? -eq 0 ]; then
+		echo "Running sysfs trace with resrv buf mode"
+		sysfs_trace $src_dev $sink_dev $cpu
+		# Restore buffer mode
+		cfg_sink_buf_mode $sink_dev "auto"
+		if [ $? -eq 1 ]; then
+			echo "Failed to restore default buf mode"
+		fi
+	fi
+}
+
+arm_cs_iterate_devices() {
+	src_dev=$1
+	cpu=$3
+	for cdev in $2/connections/out\:*; do
+
+		# Skip testing if it's not a directory
+		! [ -d $cdev ] && continue;
+
+		# Read out its symbol link file name
+		sink_dev=`readlink -f $cdev`
+
+		# Extract device name from path, e.g.
+		#   sink_dev = '/sys/devices/platform/20010000.etf/tmc_etf0'
+		#     `> sink_dev_name = 'tmc_etf0'
+		sink_dev_name=$(basename $sink_dev)
+
+		if is_device_sink $sink_dev; then
+			# Run trace with resrv buf mode (if available)
+			try_sysfs_trace_resrv_buf $src_dev $sink_dev $cpu
+
+			# Run the default mode
+			echo "Running sysfs trace with default settings"
+			sysfs_trace $src_dev $sink_dev $cpu
+		fi
+
+		arm_cs_iterate_devices $src_dev $cdev $cpu
+
+	done
+}
+
+arm_cs_etm_traverse_path_test() {
+	# Iterate for every ETM device
+	for dev in /sys/bus/event_source/devices/cs_etm/cpu*; do
+		# Canonicalize the path
+		dev=`readlink -f $dev`
+
+		# Find the ETM device belonging to which CPU
+		cpu=`cat $dev/cpu`
+
+		# Use depth-first search (DFS) to iterate outputs
+		arm_cs_iterate_devices $dev $dev $cpu
+	done
+}
+
+arm_cs_etm_traverse_path_test
+
+exit $glb_err
-- 
2.34.1