[PATCH v3 1/1] drm/i915/guc/slpc: Add selftest for slpc tile-tile interaction

[Riana Tauro <riana.tauro@xxxxxxxxx>]

Run a workload on tiles simultaneously by requesting for RP0 frequency.
Pcode can however limit the frequency being granted due to throttling
reasons. This test fails if there is any throttling

v2: Fix build error
v3: Use IS_ERR_OR_NULL to check worker
    Addressed cosmetic review comments (Tvrtko)

Signed-off-by: Riana Tauro <riana.tauro@xxxxxxxxx>
---
 drivers/gpu/drm/i915/gt/selftest_slpc.c | 60 +++++++++++++++++++++++++
 1 file changed, 60 insertions(+)

diff --git a/drivers/gpu/drm/i915/gt/selftest_slpc.c b/drivers/gpu/drm/i915/gt/selftest_slpc.c
index 82ec95a299f6..427e714b432b 100644
--- a/drivers/gpu/drm/i915/gt/selftest_slpc.c
+++ b/drivers/gpu/drm/i915/gt/selftest_slpc.c
@@ -13,6 +13,14 @@ enum test_type {
 	VARY_MAX,
 	MAX_GRANTED,
 	SLPC_POWER,
+	TILE_INTERACTION,
+};
+
+struct slpc_thread {
+	struct kthread_worker *worker;
+	struct kthread_work work;
+	struct intel_gt *gt;
+	int result;
 };
 
 static int slpc_set_min_freq(struct intel_guc_slpc *slpc, u32 freq)
@@ -310,6 +318,7 @@ static int run_test(struct intel_gt *gt, int test_type)
 			break;
 
 		case MAX_GRANTED:
+		case TILE_INTERACTION:
 			/* Media engines have a different RP0 */
 			if (engine->class == VIDEO_DECODE_CLASS ||
 			    engine->class == VIDEO_ENHANCEMENT_CLASS) {
@@ -426,6 +435,56 @@ static int live_slpc_power(void *arg)
 	return ret;
 }
 
+static void slpc_spinner_thread(struct kthread_work *work)
+{
+	struct slpc_thread *thread = container_of(work, typeof(*thread), work);
+
+	thread->result = run_test(thread->gt, TILE_INTERACTION);
+}
+
+static int live_slpc_tile_interaction(void *arg)
+{
+	struct drm_i915_private *i915 = arg;
+	struct intel_gt *gt;
+	struct slpc_thread *threads;
+	int i = 0, ret = 0;
+
+	threads = kcalloc(I915_MAX_GT, sizeof(*threads), GFP_KERNEL);
+	if (!threads)
+		return -ENOMEM;
+
+	for_each_gt(gt, i915, i) {
+		threads[i].worker = kthread_create_worker(0, "igt/slpc_parallel:%d", gt->info.id);
+
+		if (IS_ERR(threads[i].worker)) {
+			ret = PTR_ERR(threads[i].worker);
+			break;
+		}
+
+		threads[i].gt = gt;
+		kthread_init_work(&threads[i].work, slpc_spinner_thread);
+		kthread_queue_work(threads[i].worker, &threads[i].work);
+	}
+
+	for_each_gt(gt, i915, i) {
+		int status;
+
+		if (IS_ERR_OR_NULL(threads[i].worker))
+			continue;
+
+		kthread_flush_work(&threads[i].work);
+		status = READ_ONCE(threads[i].result);
+		if (status && !ret) {
+			pr_err("%s GT %d failed ", __func__, gt->info.id);
+			ret = status;
+		}
+		kthread_destroy_worker(threads[i].worker);
+	}
+
+	kfree(threads);
+	return ret;
+}
+
 int intel_slpc_live_selftests(struct drm_i915_private *i915)
 {
 	static const struct i915_subtest tests[] = {
@@ -433,6 +492,7 @@ int intel_slpc_live_selftests(struct drm_i915_private *i915)
 		SUBTEST(live_slpc_vary_min),
 		SUBTEST(live_slpc_max_granted),
 		SUBTEST(live_slpc_power),
+		SUBTEST(live_slpc_tile_interaction),
 	};
 
 	struct intel_gt *gt;
-- 
2.25.1