[PATCH v2] selftests: arm coresight: sysfsmode testing - CoreSight

19 Dec 2024

Add sysfs mode selftest for ARM Coresight hardware tracer.
The test will run below sequence for all possible sinks for every
trace source available on the system.
1. Enable source and sink device to start tracing in sysfs mode
3. Run a standard dd command to be traced
4. Stop tracing
5. Readback tracedata
- Test case is pass if the readback of tracedata is success else
failure.
- In case of ETR sink, the test is run with both default buffer mode and
reserved buffer mode(if available).
Sample output:
selftests: drivers/hwtracing/coresight: sysfs_test_trace.sh
 Running sysfs trace with default settings
 64+0 records in
 64+0 records out
 67108864 bytes (67 MB, 64 MiB) copied, 0.196945 s, 341 MB/s
 32+0 records in
 32+0 records out
 16384 bytes (16 kB, 16 KiB) copied, 0.000805288 s, 20.3 MB/s
 CoreSight path testing (CPU0 -> tmc_etf0): PASS
Signed-off-by: Linu Cherian lcherian@marvell.com
---
Changelog from v1:
- Added test description in commit message suggested by Shuah
- Added config dependency file suggested by Shuah 
- Added TARGETS as suggested by James
- Skipped TPIU as suggested by James 
- Added Reviewed-by tag
tools/testing/selftests/Makefile              |   1 +
 .../drivers/hwtracing/coresight/Makefile      |   5 +
 .../drivers/hwtracing/coresight/config        |   7 +
 .../hwtracing/coresight/sysfs_test_trace.sh   | 146 ++++++++++++++++++
 4 files changed, 159 insertions(+)
 create mode 100644 tools/testing/selftests/drivers/hwtracing/coresight/Makefile
 create mode 100644 tools/testing/selftests/drivers/hwtracing/coresight/config
 create mode 100755 tools/testing/selftests/drivers/hwtracing/coresight/sysfs_test_trace.sh

diff --git a/tools/testing/selftests/Makefile b/tools/testing/selftests/Makefile
index 363d031a16f7..15788c32de6b 100644
--- a/tools/testing/selftests/Makefile
+++ b/tools/testing/selftests/Makefile
@@ -18,6 +18,7 @@ TARGETS += devices/error_logs
 TARGETS += devices/probe
 TARGETS += dmabuf-heaps
 TARGETS += drivers/dma-buf
+TARGETS += drivers/hwtracing/coresight
 TARGETS += drivers/s390x/uvdevice
 TARGETS += drivers/net
 TARGETS += drivers/net/bonding
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/config b/tools/testing/selftests/drivers/hwtracing/coresight/config
new file mode 100644
index 000000000000..47e9256957d3
--- /dev/null
+++ b/tools/testing/selftests/drivers/hwtracing/coresight/config
@@ -0,0 +1,7 @@
+CONFIG_CORESIGHT=y
+CONFIG_CORESIGHT_LINKS_AND_SINKS=y
+CONFIG_CORESIGHT_LINK_AND_SINK_TMC=y
+CONFIG_CORESIGHT_SINK_ETBV10
+CONFIG_CORESIGHT_SOURCE_ETM3X
+CONFIG_CORESIGHT_SOURCE_ETM4X=y
+CONFIG_CORESIGHT_TRBE=y
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..1939bbede1af
--- /dev/null
+++ b/tools/testing/selftests/drivers/hwtracing/coresight/sysfs_test_trace.sh
@@ -0,0 +1,146 @@
+#!/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. Need to exclude 'tpiu' since it
+	# doesn't have a readable file.
+	echo "$1" | grep -E -q -v "tpiu"
+
+	if [ $? -eq 0 ] && [ -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


    