[PATCH] kselftest: cpufreq: Backup and restore governor for sptests

[Yiwei Lin <s921975628@gmail.com>]

After executing cpufreq sptest, the system governor
will be overwritten with the governor switched
during the test. Restore this setting to maintain
consistency before and after the test.

Signed-off-by: Yiwei Lin <s921975628@gmail.com>
---
 tools/testing/selftests/cpufreq/governor.sh   | 21 +++++++++++++++++++
 .../selftests/cpufreq/special-tests.sh        | 13 ++++++++++++
 2 files changed, 34 insertions(+)

diff --git a/tools/testing/selftests/cpufreq/governor.sh b/tools/testing/selftests/cpufreq/governor.sh
index fe37df79c0871..5d105ab9c9222 100755
--- a/tools/testing/selftests/cpufreq/governor.sh
+++ b/tools/testing/selftests/cpufreq/governor.sh
@@ -16,6 +16,12 @@ source cpufreq.sh
 CUR_GOV=
 CUR_FREQ=
 
+# Per-policy backup, keyed by policy so multiple policies can be saved at once
+# (backup_governor/restore_governor also keep CUR_GOV/CUR_FREQ for callers that
+# read them directly).
+declare -A SAVED_GOVERNORS
+declare -A SAVED_FREQS
+
 # Find governor's directory path
 # $1: policy, $2: governor
 find_gov_directory()
@@ -39,11 +45,13 @@ find_current_governor()
 backup_governor()
 {
 	CUR_GOV=$(find_current_governor $1)
+	SAVED_GOVERNORS[$1]=$CUR_GOV
 
 	printf "Governor backup done for $1: $CUR_GOV\n"
 
 	if [ $CUR_GOV == "userspace" ]; then
 		CUR_FREQ=$(find_current_freq $1)
+		SAVED_FREQS[$1]=$CUR_FREQ
 		printf "Governor frequency backup done for $1: $CUR_FREQ\n"
 	fi
 
@@ -53,11 +61,13 @@ backup_governor()
 # $1: policy
 restore_governor()
 {
+	CUR_GOV=${SAVED_GOVERNORS[$1]}
 	__switch_governor $1 $CUR_GOV
 
 	printf "Governor restored for $1 to $CUR_GOV\n"
 
 	if [ $CUR_GOV == "userspace" ]; then
+		CUR_FREQ=${SAVED_FREQS[$1]}
 		set_cpu_frequency $1 $CUR_FREQ
 		printf "Governor frequency restored for $1: $CUR_FREQ\n"
 	fi
@@ -65,6 +75,17 @@ restore_governor()
 	printf "\n"
 }
 
+# Save/restore governors for every policy at once
+save_all_governors()
+{
+	for_each_policy backup_governor
+}
+
+restore_all_governors()
+{
+	for_each_policy restore_governor
+}
+
 # param:
 # $1: policy, $2: governor
 __switch_governor()
diff --git a/tools/testing/selftests/cpufreq/special-tests.sh b/tools/testing/selftests/cpufreq/special-tests.sh
index 8d40505dc4682..c7eddadd047d1 100755
--- a/tools/testing/selftests/cpufreq/special-tests.sh
+++ b/tools/testing/selftests/cpufreq/special-tests.sh
@@ -40,7 +40,9 @@ simple_lockdep()
 {
 	printf "** Test: Running ${FUNCNAME[0]} **\n"
 
+	save_all_governors
 	for_each_policy __simple_lockdep
+	restore_all_governors
 }
 
 # Test 2
@@ -56,7 +58,10 @@ concurrent_lockdep()
 {
 	printf "** Test: Running ${FUNCNAME[0]} **\n"
 
+	save_all_governors
 	for_each_policy_concurrent __concurrent_lockdep
+	wait
+	restore_all_governors
 }
 
 # Test 3
@@ -68,17 +73,23 @@ quick_shuffle()
 		echo ondemand | sudo tee $CPUFREQROOT/policy*/scaling_governor &
 		echo userspace | sudo tee $CPUFREQROOT/policy*/scaling_governor &
 	done
+	wait
 }
 
 governor_race()
 {
 	printf "** Test: Running ${FUNCNAME[0]} **\n"
 
+	save_all_governors
+
 	# run 8 concurrent instances
 	for I in `seq 8`
 	do
 		quick_shuffle &
 	done
+	wait
+
+	restore_all_governors
 }
 
 # Test 4
@@ -112,5 +123,7 @@ hotplug_with_updates_cpu()
 
 hotplug_with_updates()
 {
+	save_all_governors
 	for_each_non_boot_cpu hotplug_with_updates_cpu
+	restore_all_governors
 }
-- 
2.34.1