[PATCH net-next v3 08/14] selftests: dpll: add pin priority test

[Petr Oros <poros@redhat.com>]

Add a test that sets a new priority on an input pin, reads it back and
restores the original value. The range of priorities a device accepts is
not advertised over netlink, so the test tries one below the current
value and then the small values every driver accepts, since a large
current value may mark an unused pin outside the settable range, as the
ice driver does with 255. A driver may still refuse all of them for a
constraint the interface does not tell, so that is a skip on a device
provided by the user, with the reason the tool reported, and a failure
on the device the script created, whose simulator accepts every
priority. The test skips when the dpll tool lacks the prio keyword of
pin set, and the restore is deferred right after the original value is
read so that an interrupted run restores it too. A pin that does not
advertise the priority-can-change capability or does not report a
priority is a skip on a device provided by the user and a failure on the
device the script created, whose pins have both.

The dpllsim_add_pin helper gains an optional priority argument, which is
written only when it is given, so that a pin without one keeps the
default of the simulator. A priority is accepted for input pins only,
so the callers pass one for those alone.

The standard device lays its inputs out as gnss0 with priority 0 and
ext0 with priority 1, and the stress devices get random priorities on
their input pins.

Reviewed-by: Ivan Vecera <ivecera@redhat.com>
Acked-by: Jiri Pirko <jiri@nvidia.com>
Signed-off-by: Petr Oros <poros@redhat.com>
---
v3:
- follow the move of the selftests to
  tools/testing/selftests/drivers/dpll

v2: https://lore.kernel.org/all/20261105151852.1844305-9-poros@redhat.com/
v1: https://lore.kernel.org/all/20261103093910.596225-9-poros@redhat.com/
---
 .../selftests/drivers/dpll/dpll_features.sh   | 65 +++++++++++++++++++
 .../selftests/drivers/dpll/dpll_lib.sh        | 32 +++++++--
 .../selftests/drivers/dpll/dpll_stress.sh     | 15 +++--
 3 files changed, 100 insertions(+), 12 deletions(-)

diff --git a/tools/testing/selftests/drivers/dpll/dpll_features.sh b/tools/testing/selftests/drivers/dpll/dpll_features.sh
index 874007411bc5e7..b4b1eff322a219 100755
--- a/tools/testing/selftests/drivers/dpll/dpll_features.sh
+++ b/tools/testing/selftests/drivers/dpll/dpll_features.sh
@@ -17,6 +17,7 @@ source "$SCRIPTDIR/dpll_lib.sh"
 
 ALL_TESTS="
 	test_pin_state_transitions
+	test_pin_priority_get_set
 "
 
 ##############################################################################
@@ -37,6 +38,70 @@ find_connected_pin()
 	done
 }
 
+test_pin_priority_get_set()
+{
+	local before target after reason candidate
+
+	RET=0
+
+	if [ -z "$PIN_TUNE_ID" ]; then
+		dpll_log_test_skip_or_fail "DPLL pin priority set/get" \
+		    "no spare input pin"
+		return
+	fi
+	if ! dpll_pin_set_supports prio; then
+		log_test_skip "DPLL pin priority set/get" \
+		    "dpll tool lacks pin set prio"
+		return
+	fi
+	if ! dpll_pin_has_capability "$PIN_TUNE_ID" priority-can-change; then
+		dpll_log_test_skip_or_fail "DPLL pin priority set/get" \
+		    "priority cannot change"
+		return
+	fi
+
+	before=$(dpll_pin_get_prio "$DPLL_DEV_ID" "$PIN_TUNE_ID")
+	if [ -z "$before" ]; then
+		dpll_log_test_skip_or_fail "DPLL pin priority set/get" \
+		    "prio not reported"
+		return
+	fi
+	defer dpll_pin_set_prio "$DPLL_DEV_ID" "$PIN_TUNE_ID" "$before"
+
+	# The accepted range is not advertised, so try one below the current
+	# value and then small values, a refusal of all of them is a skip on
+	# a device the user provided, the simulator accepts every priority.
+	target=""
+	for candidate in $((before - 1)) 1 7; do
+		[ "$candidate" -ge 0 ] && [ "$candidate" != "$before" ] ||
+			continue
+		if dpll_pin_set_prio "$DPLL_DEV_ID" "$PIN_TUNE_ID" \
+				     "$candidate"; then
+			target=$candidate
+			break
+		fi
+		reason=${DPLL_LAST_ERR%%$'\n'*}
+	done
+	if [ -z "$target" ]; then
+		dpll_log_test_skip_or_fail "DPLL pin priority set/get" \
+		    "cannot set a new prio${reason:+, $reason}"
+		return
+	fi
+	after=$(dpll_pin_get_prio "$DPLL_DEV_ID" "$PIN_TUNE_ID")
+	if [ "$after" != "$target" ]; then
+		check_err 1 "priority expected $target, got '$after'"
+	fi
+
+	dpll_pin_set_prio "$DPLL_DEV_ID" "$PIN_TUNE_ID" "$before"
+	check_err $? "cannot restore pin priority"
+	after=$(dpll_pin_get_prio "$DPLL_DEV_ID" "$PIN_TUNE_ID")
+	if [ "$after" != "$before" ]; then
+		check_err 1 "priority not restored, got '$after'"
+	fi
+
+	log_test "DPLL pin priority set/get"
+}
+
 test_pin_state_transitions()
 {
 	local mode before state after reason ref_pin
diff --git a/tools/testing/selftests/drivers/dpll/dpll_lib.sh b/tools/testing/selftests/drivers/dpll/dpll_lib.sh
index 63c70a4aaab6e2..6fe707c2609c55 100644
--- a/tools/testing/selftests/drivers/dpll/dpll_lib.sh
+++ b/tools/testing/selftests/drivers/dpll/dpll_lib.sh
@@ -395,6 +395,11 @@ dpll_pin_has_capability()
 	   <<< "$out" &> /dev/null
 }
 
+dpll_pin_get_prio()
+{
+	__dpll_pin_dev_field "$1" "$2" '.prio'
+}
+
 ##############################################################################
 # Pin setters
 #
@@ -416,6 +421,16 @@ dpll_pin_set_state()
 			     state "$state" 2>&1 >/dev/null)
 }
 
+dpll_pin_set_prio()
+{
+	local dev_id=$1
+	local pin_id=$2
+	local prio=$3
+
+	DPLL_LAST_ERR=$(dpll pin set id "$pin_id" parent-device "$dev_id" \
+			     prio "$prio" 2>&1 >/dev/null)
+}
+
 ##############################################################################
 # dpllsim configfs interface
 #
@@ -497,7 +512,9 @@ dpllsim_create_device()
 
 # $1: device name, $2: pin name (becomes the board-label), $3: type (gnss,
 # int-oscillator, ext, synce-eth-port, mux), $4: frequency in Hz,
-# $5: direction (input/output)
+# $5: direction (input/output), $6: prio (optional, input pins only).
+# The priority is written only when one is given, so a pin without one
+# keeps the default of the simulator.
 dpllsim_add_pin()
 {
 	local dev=$1
@@ -505,13 +522,16 @@ dpllsim_add_pin()
 	local type=$3
 	local frequency=$4
 	local direction=$5
+	local prio=${6:-}
 	local pin_path="$DPLLSIM_CFG/$dev/pins/$pin"
 
 	mkdir "$pin_path" 2>/dev/null || return 1
 
 	if ! echo "$type" 2>/dev/null > "$pin_path/type" ||
 	   ! echo "$frequency" 2>/dev/null > "$pin_path/frequency" ||
-	   ! echo "$direction" 2>/dev/null > "$pin_path/direction"; then
+	   ! echo "$direction" 2>/dev/null > "$pin_path/direction" ||
+	   { [ -n "$prio" ] &&
+	     ! echo "$prio" 2>/dev/null > "$pin_path/prio"; }; then
 		rmdir "$pin_path" 2>/dev/null
 		return 1
 	fi
@@ -559,8 +579,8 @@ dpllsim_alloc_clock_id()
 # Create a device with the standard 3-pin layout, deploy it and resolve
 # the netlink device id. Sets DPLLSIM_CREATED_NAME, DPLLSIM_CLOCK_ID and
 # DPLLSIM_DEV_ID.
-#   gnss0: GNSS, 1 Hz, input
-#   ext0: EXT, 10 MHz, input
+#   gnss0: GNSS, 1 Hz, input, prio 0 (active reference)
+#   ext0: EXT, 10 MHz, input, prio 1
 #   out0: EXT, 10 MHz, output
 # shellcheck disable=SC2120 # the argument is optional
 dpllsim_setup_standard_device()
@@ -572,8 +592,8 @@ dpllsim_setup_standard_device()
 	name="std$clock_id"
 	dpllsim_create_device "$name" "$clock_id" || return 1
 
-	if ! dpllsim_add_pin "$name" gnss0 gnss 1 input ||
-	   ! dpllsim_add_pin "$name" ext0 ext 10000000 input ||
+	if ! dpllsim_add_pin "$name" gnss0 gnss 1 input 0 ||
+	   ! dpllsim_add_pin "$name" ext0 ext 10000000 input 1 ||
 	   ! dpllsim_add_pin "$name" out0 ext 10000000 output; then
 		dpllsim_delete_device "$name"
 		return 1
diff --git a/tools/testing/selftests/drivers/dpll/dpll_stress.sh b/tools/testing/selftests/drivers/dpll/dpll_stress.sh
index 526cb113807f72..3806fda2e2dfe0 100755
--- a/tools/testing/selftests/drivers/dpll/dpll_stress.sh
+++ b/tools/testing/selftests/drivers/dpll/dpll_stress.sh
@@ -77,13 +77,13 @@ create_stress_device()
 	local clock_id=$1
 	local num_pins=$2
 	local name="st$clock_id"
-	local i type freq dir
+	local i type freq dir prio
 	local dirs=(input output)
 
 	dpllsim_create_device "$name" "$clock_id" || return 1
 
 	# Always have at least one plain input pin, then random ones
-	if ! dpllsim_add_pin "$name" ext0 ext 10000000 input; then
+	if ! dpllsim_add_pin "$name" ext0 ext 10000000 input 1; then
 		dpllsim_delete_device "$name"
 		return 1
 	fi
@@ -94,8 +94,11 @@ create_stress_device()
 		# output one
 		dir=${dirs[RANDOM % 2]}
 		[ "$type" = mux ] && dir=input
-		if ! dpllsim_add_pin "$name" "pin$i" "$type" "$freq" \
-				     "$dir"; then
+		# Only input pins accept a priority
+		prio=""
+		[ "$dir" = input ] && prio=$((RANDOM % 128))
+		if ! dpllsim_add_pin "$name" "pin$i" "$type" "$freq" "$dir" \
+				     "$prio"; then
 			dpllsim_delete_device "$name"
 			return 1
 		fi
@@ -206,8 +209,8 @@ test_deploy_cycle()
 	fi
 	track_device "$name"
 
-	if ! dpllsim_add_pin "$name" gnss0 gnss 1 input ||
-	   ! dpllsim_add_pin "$name" ext0 ext 10000000 input ||
+	if ! dpllsim_add_pin "$name" gnss0 gnss 1 input 0 ||
+	   ! dpllsim_add_pin "$name" ext0 ext 10000000 input 1 ||
 	   ! dpllsim_add_pin "$name" out0 ext 10000000 output; then
 		check_err 1 "cannot add pins"
 		log_test "DPLL deploy/undeploy cycling"
-- 
2.56.0