drm/i915/guc/slpc: Add a new SLPC selftest

This test will validate we can achieve actual frequency of RP0. Pcode
grants frequencies based on what GuC is requesting. However, thermal
throttling can limit what is being granted. Add a test to request for
max, but don't fail the test if RP0 is not granted due to throttle
reasons.

Also optimize the selftest by using a common run_test function to avoid
code duplication. Rename the "clamp" tests to vary_max_freq and
vary_min_freq.

v2: Fix compile warning
v3: Review comments (Ashutosh). Added a FIXME for the media RP0 case.
v4: Checkpatch (strict) fixes, remove FIXME and other comments (Ashutosh)

Fixes commit 8ee2c227 ("drm/i915/guc/slpc: Add SLPC selftest")

Cc: Ashutosh Dixit <ashutosh.dixit@intel.com>
Signed-off-by: Vinay Belgaumkar <vinay.belgaumkar@intel.com>
Reviewed-by: Ashutosh Dixit <ashutosh.dixit@intel.com>
Signed-off-by: John Harrison <John.C.Harrison@Intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220627230346.27720-1-vinay.belgaumkar@intel.com

drivers/gpu/drm/i915/gt/selftest_slpc.c

@@ -8,6 +8,11 @@
 #define delay_for_h2g() usleep_range(H2G_DELAY, H2G_DELAY + 10000)
 #define FREQUENCY_REQ_UNIT	DIV_ROUND_CLOSEST(GT_FREQUENCY_MULTIPLIER, \
 						  GEN9_FREQ_SCALER)
+enum test_type {
+	VARY_MIN,
+	VARY_MAX,
+	MAX_GRANTED
+};
 
 static int slpc_set_min_freq(struct intel_guc_slpc *slpc, u32 freq)
 {
@@ -36,147 +41,114 @@ static int slpc_set_max_freq(struct intel_guc_slpc *slpc, u32 freq)
 	return ret;
 }
 
-static int live_slpc_clamp_min(void *arg)
+static int vary_max_freq(struct intel_guc_slpc *slpc, struct intel_rps *rps,
+			 u32 *max_act_freq)
 {
-	struct drm_i915_private *i915 = arg;
-	struct intel_gt *gt = to_gt(i915);
-	struct intel_guc_slpc *slpc = &gt->uc.guc.slpc;
-	struct intel_rps *rps = &gt->rps;
-	struct intel_engine_cs *engine;
-	enum intel_engine_id id;
-	struct igt_spinner spin;
-	u32 slpc_min_freq, slpc_max_freq;
+	u32 step, max_freq, req_freq;
+	u32 act_freq;
 	int err = 0;
 
-	if (!intel_uc_uses_guc_slpc(&gt->uc))
-		return 0;
+	/* Go from max to min in 5 steps */
+	step = (slpc->rp0_freq - slpc->min_freq) / NUM_STEPS;
+	*max_act_freq = slpc->min_freq;
+	for (max_freq = slpc->rp0_freq; max_freq > slpc->min_freq;
+				max_freq -= step) {
+		err = slpc_set_max_freq(slpc, max_freq);
+		if (err)
+			break;
 
-	if (igt_spinner_init(&spin, gt))
-		return -ENOMEM;
+		req_freq = intel_rps_read_punit_req_frequency(rps);
 
-	if (intel_guc_slpc_get_max_freq(slpc, &slpc_max_freq)) {
-		pr_err("Could not get SLPC max freq\n");
-		return -EIO;
-	}
+		/* GuC requests freq in multiples of 50/3 MHz */
+		if (req_freq > (max_freq + FREQUENCY_REQ_UNIT)) {
+			pr_err("SWReq is %d, should be at most %d\n", req_freq,
+			       max_freq + FREQUENCY_REQ_UNIT);
+			err = -EINVAL;
+		}
 
-	if (intel_guc_slpc_get_min_freq(slpc, &slpc_min_freq)) {
-		pr_err("Could not get SLPC min freq\n");
-		return -EIO;
-	}
+		act_freq =  intel_rps_read_actual_frequency(rps);
+		if (act_freq > *max_act_freq)
+			*max_act_freq = act_freq;
 
-	if (slpc_min_freq == slpc_max_freq) {
-		pr_err("Min/Max are fused to the same value\n");
-		return -EINVAL;
+		if (err)
+			break;
 	}
 
-	intel_gt_pm_wait_for_idle(gt);
-	intel_gt_pm_get(gt);
-	for_each_engine(engine, gt, id) {
-		struct i915_request *rq;
-		u32 step, min_freq, req_freq;
-		u32 act_freq, max_act_freq;
+	return err;
+}
 
-		if (!intel_engine_can_store_dword(engine))
-			continue;
+static int vary_min_freq(struct intel_guc_slpc *slpc, struct intel_rps *rps,
+			 u32 *max_act_freq)
+{
+	u32 step, min_freq, req_freq;
+	u32 act_freq;
+	int err = 0;
 
-		/* Go from min to max in 5 steps */
-		step = (slpc_max_freq - slpc_min_freq) / NUM_STEPS;
-		max_act_freq = slpc_min_freq;
-		for (min_freq = slpc_min_freq; min_freq < slpc_max_freq;
-					min_freq += step) {
-			err = slpc_set_min_freq(slpc, min_freq);
-			if (err)
-				break;
-
-			st_engine_heartbeat_disable(engine);
-
-			rq = igt_spinner_create_request(&spin,
-							engine->kernel_context,
-							MI_NOOP);
-			if (IS_ERR(rq)) {
-				err = PTR_ERR(rq);
-				st_engine_heartbeat_enable(engine);
-				break;
-			}
+	/* Go from min to max in 5 steps */
+	step = (slpc->rp0_freq - slpc->min_freq) / NUM_STEPS;
+	*max_act_freq = slpc->min_freq;
+	for (min_freq = slpc->min_freq; min_freq < slpc->rp0_freq;
+				min_freq += step) {
+		err = slpc_set_min_freq(slpc, min_freq);
+		if (err)
+			break;
 
-			i915_request_add(rq);
+		req_freq = intel_rps_read_punit_req_frequency(rps);
 
-			if (!igt_wait_for_spinner(&spin, rq)) {
-				pr_err("%s: Spinner did not start\n",
-				       engine->name);
-				igt_spinner_end(&spin);
-				st_engine_heartbeat_enable(engine);
-				intel_gt_set_wedged(engine->gt);
-				err = -EIO;
-				break;
-			}
+		/* GuC requests freq in multiples of 50/3 MHz */
+		if (req_freq < (min_freq - FREQUENCY_REQ_UNIT)) {
+			pr_err("SWReq is %d, should be at least %d\n", req_freq,
+			       min_freq - FREQUENCY_REQ_UNIT);
+			err = -EINVAL;
+		}
 
-			/* Wait for GuC to detect business and raise
-			 * requested frequency if necessary.
-			 */
-			delay_for_h2g();
+		act_freq =  intel_rps_read_actual_frequency(rps);
+		if (act_freq > *max_act_freq)
+			*max_act_freq = act_freq;
 
-			req_freq = intel_rps_read_punit_req_frequency(rps);
+		if (err)
+			break;
+	}
 
-			/* GuC requests freq in multiples of 50/3 MHz */
-			if (req_freq < (min_freq - FREQUENCY_REQ_UNIT)) {
-				pr_err("SWReq is %d, should be at least %d\n", req_freq,
-				       min_freq - FREQUENCY_REQ_UNIT);
-				igt_spinner_end(&spin);
-				st_engine_heartbeat_enable(engine);
-				err = -EINVAL;
-				break;
-			}
+	return err;
+}
 
-			act_freq =  intel_rps_read_actual_frequency(rps);
-			if (act_freq > max_act_freq)
-				max_act_freq = act_freq;
+static int max_granted_freq(struct intel_guc_slpc *slpc, struct intel_rps *rps, u32 *max_act_freq)
+{
+	struct intel_gt *gt = rps_to_gt(rps);
+	u32 perf_limit_reasons;
+	int err = 0;
 
-			igt_spinner_end(&spin);
-			st_engine_heartbeat_enable(engine);
-		}
+	err = slpc_set_min_freq(slpc, slpc->rp0_freq);
+	if (err)
+		return err;
 
-		pr_info("Max actual frequency for %s was %d\n",
-			engine->name, max_act_freq);
+	*max_act_freq =  intel_rps_read_actual_frequency(rps);
+	if (*max_act_freq != slpc->rp0_freq) {
+		/* Check if there was some throttling by pcode */
+		perf_limit_reasons = intel_uncore_read(gt->uncore, GT0_PERF_LIMIT_REASONS);
 
-		/* Actual frequency should rise above min */
-		if (max_act_freq == slpc_min_freq) {
-			pr_err("Actual freq did not rise above min\n");
+		/* If not, this is an error */
+		if (!(perf_limit_reasons & GT0_PERF_LIMIT_REASONS_MASK)) {
+			pr_err("Pcode did not grant max freq\n");
 			err = -EINVAL;
+		} else {
+			pr_info("Pcode throttled frequency 0x%x\n", perf_limit_reasons);
 		}
-
-		if (err)
-			break;
 	}
 
-	/* Restore min/max frequencies */
-	slpc_set_max_freq(slpc, slpc_max_freq);
-	slpc_set_min_freq(slpc, slpc_min_freq);
-
-	if (igt_flush_test(gt->i915))
-		err = -EIO;
-
-	intel_gt_pm_put(gt);
-	igt_spinner_fini(&spin);
-	intel_gt_pm_wait_for_idle(gt);
-
 	return err;
 }
 
-static int live_slpc_clamp_max(void *arg)
+static int run_test(struct intel_gt *gt, int test_type)
 {
-	struct drm_i915_private *i915 = arg;
-	struct intel_gt *gt = to_gt(i915);
-	struct intel_guc_slpc *slpc;
-	struct intel_rps *rps;
+	struct intel_guc_slpc *slpc = &gt->uc.guc.slpc;
+	struct intel_rps *rps = &gt->rps;
 	struct intel_engine_cs *engine;
 	enum intel_engine_id id;
 	struct igt_spinner spin;
-	int err = 0;
 	u32 slpc_min_freq, slpc_max_freq;
-
-	slpc = &gt->uc.guc.slpc;
-	rps = &gt->rps;
+	int err = 0;
 
 	if (!intel_uc_uses_guc_slpc(&gt->uc))
 		return 0;
@@ -194,7 +166,7 @@ static int live_slpc_clamp_max(void *arg)
 		return -EIO;
 	}
 
-	if (slpc_min_freq == slpc_max_freq) {
+	if (slpc->min_freq == slpc->rp0_freq) {
 		pr_err("Min/Max are fused to the same value\n");
 		return -EINVAL;
 	}
@@ -203,93 +175,82 @@ static int live_slpc_clamp_max(void *arg)
 	intel_gt_pm_get(gt);
 	for_each_engine(engine, gt, id) {
 		struct i915_request *rq;
-		u32 max_freq, req_freq;
-		u32 act_freq, max_act_freq;
-		u32 step;
+		u32 max_act_freq;
 
 		if (!intel_engine_can_store_dword(engine))
 			continue;
 
-		/* Go from max to min in 5 steps */
-		step = (slpc_max_freq - slpc_min_freq) / NUM_STEPS;
-		max_act_freq = slpc_min_freq;
-		for (max_freq = slpc_max_freq; max_freq > slpc_min_freq;
-					max_freq -= step) {
-			err = slpc_set_max_freq(slpc, max_freq);
-			if (err)
-				break;
-
-			st_engine_heartbeat_disable(engine);
-
-			rq = igt_spinner_create_request(&spin,
-							engine->kernel_context,
-							MI_NOOP);
-			if (IS_ERR(rq)) {
-				st_engine_heartbeat_enable(engine);
-				err = PTR_ERR(rq);
-				break;
-			}
+		st_engine_heartbeat_disable(engine);
 
-			i915_request_add(rq);
+		rq = igt_spinner_create_request(&spin,
+						engine->kernel_context,
+						MI_NOOP);
+		if (IS_ERR(rq)) {
+			err = PTR_ERR(rq);
+			st_engine_heartbeat_enable(engine);
+			break;
+		}
 
-			if (!igt_wait_for_spinner(&spin, rq)) {
-				pr_err("%s: SLPC spinner did not start\n",
-				       engine->name);
-				igt_spinner_end(&spin);
-				st_engine_heartbeat_enable(engine);
-				intel_gt_set_wedged(engine->gt);
-				err = -EIO;
-				break;
-			}
+		i915_request_add(rq);
 
-			delay_for_h2g();
+		if (!igt_wait_for_spinner(&spin, rq)) {
+			pr_err("%s: Spinner did not start\n",
+			       engine->name);
+			igt_spinner_end(&spin);
+			st_engine_heartbeat_enable(engine);
+			intel_gt_set_wedged(engine->gt);
+			err = -EIO;
+			break;
+		}
 
-			/* Verify that SWREQ indeed was set to specific value */
-			req_freq = intel_rps_read_punit_req_frequency(rps);
+		switch (test_type) {
+		case VARY_MIN:
+			err = vary_min_freq(slpc, rps, &max_act_freq);
+			break;
 
-			/* GuC requests freq in multiples of 50/3 MHz */
-			if (req_freq > (max_freq + FREQUENCY_REQ_UNIT)) {
-				pr_err("SWReq is %d, should be at most %d\n", req_freq,
-				       max_freq + FREQUENCY_REQ_UNIT);
+		case VARY_MAX:
+			err = vary_max_freq(slpc, rps, &max_act_freq);
+			break;
+
+		case MAX_GRANTED:
+			/* Media engines have a different RP0 */
+			if (engine->class == VIDEO_DECODE_CLASS ||
+			    engine->class == VIDEO_ENHANCEMENT_CLASS) {
 				igt_spinner_end(&spin);
 				st_engine_heartbeat_enable(engine);
-				err = -EINVAL;
-				break;
+				err = 0;
+				continue;
 			}
 
-			act_freq =  intel_rps_read_actual_frequency(rps);
-			if (act_freq > max_act_freq)
-				max_act_freq = act_freq;
-
-			st_engine_heartbeat_enable(engine);
-			igt_spinner_end(&spin);
-
-			if (err)
-				break;
+			err = max_granted_freq(slpc, rps, &max_act_freq);
+			break;
 		}
 
 		pr_info("Max actual frequency for %s was %d\n",
 			engine->name, max_act_freq);
 
 		/* Actual frequency should rise above min */
-		if (max_act_freq == slpc_min_freq) {
+		if (max_act_freq <= slpc_min_freq) {
 			pr_err("Actual freq did not rise above min\n");
+			pr_err("Perf Limit Reasons: 0x%x\n",
+			       intel_uncore_read(gt->uncore, GT0_PERF_LIMIT_REASONS));
 			err = -EINVAL;
 		}
 
-		if (igt_flush_test(gt->i915)) {
-			err = -EIO;
-			break;
-		}
+		igt_spinner_end(&spin);
+		st_engine_heartbeat_enable(engine);
 
 		if (err)
 			break;
 	}
 
-	/* Restore min/max freq */
+	/* Restore min/max frequencies */
 	slpc_set_max_freq(slpc, slpc_max_freq);
 	slpc_set_min_freq(slpc, slpc_min_freq);
 
+	if (igt_flush_test(gt->i915))
+		err = -EIO;
+
 	intel_gt_pm_put(gt);
 	igt_spinner_fini(&spin);
 	intel_gt_pm_wait_for_idle(gt);
@@ -297,11 +258,37 @@ static int live_slpc_clamp_max(void *arg)
 	return err;
 }
 
+static int live_slpc_vary_min(void *arg)
+{
+	struct drm_i915_private *i915 = arg;
+	struct intel_gt *gt = to_gt(i915);
+
+	return run_test(gt, VARY_MIN);
+}
+
+static int live_slpc_vary_max(void *arg)
+{
+	struct drm_i915_private *i915 = arg;
+	struct intel_gt *gt = to_gt(i915);
+
+	return run_test(gt, VARY_MAX);
+}
+
+/* check if pcode can grant RP0 */
+static int live_slpc_max_granted(void *arg)
+{
+	struct drm_i915_private *i915 = arg;
+	struct intel_gt *gt = to_gt(i915);
+
+	return run_test(gt, MAX_GRANTED);
+}
+
 int intel_slpc_live_selftests(struct drm_i915_private *i915)
 {
 	static const struct i915_subtest tests[] = {
-		SUBTEST(live_slpc_clamp_max),
-		SUBTEST(live_slpc_clamp_min),
+		SUBTEST(live_slpc_vary_max),
+		SUBTEST(live_slpc_vary_min),
+		SUBTEST(live_slpc_max_granted),
 	};
 
 	if (intel_gt_is_wedged(to_gt(i915)))