drm/i915/guc/slpc: Add SLPC selftest

Tests that exercise the SLPC get/set frequency interfaces.

Clamp_max will set max frequency to multiple levels and check
that SLPC requests frequency lower than or equal to it.

Clamp_min will set min frequency to different levels and check
if SLPC requests are higher or equal to those levels.

v2: Address review comments (Michal W)
v3: Checkpatch() corrections
v4: Remove unnecessary header file (Matthew Brost)
v5: checkpatch() and define const for 50/3 (Matthew Brost)

Reviewed-by: Matthew Brost <matthew.brost@intel.com>
Signed-off-by: Vinay Belgaumkar <vinay.belgaumkar@intel.com>
Signed-off-by: John Harrison <John.C.Harrison@Intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210730202119.23810-14-vinay.belgaumkar@intel.com

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

@@ -2333,4 +2333,5 @@ EXPORT_SYMBOL_GPL(i915_gpu_turbo_disable);
 
 #if IS_ENABLED(CONFIG_DRM_I915_SELFTEST)
 #include "selftest_rps.c"
+#include "selftest_slpc.c"
 #endif

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

+// SPDX-License-Identifier: MIT
+/*
+ * Copyright © 2021 Intel Corporation
+ */
+
+#define NUM_STEPS 5
+#define H2G_DELAY 50000
+#define delay_for_h2g() usleep_range(H2G_DELAY, H2G_DELAY + 10000)
+#define FREQUENCY_REQ_UNIT	DIV_ROUND_CLOSEST(GT_FREQUENCY_MULTIPLIER, \
+						  GEN9_FREQ_SCALER)
+
+static int slpc_set_min_freq(struct intel_guc_slpc *slpc, u32 freq)
+{
+	int ret;
+
+	ret = intel_guc_slpc_set_min_freq(slpc, freq);
+	if (ret)
+		pr_err("Could not set min frequency to [%u]\n", freq);
+	else /* Delay to ensure h2g completes */
+		delay_for_h2g();
+
+	return ret;
+}
+
+static int slpc_set_max_freq(struct intel_guc_slpc *slpc, u32 freq)
+{
+	int ret;
+
+	ret = intel_guc_slpc_set_max_freq(slpc, freq);
+	if (ret)
+		pr_err("Could not set maximum frequency [%u]\n",
+		       freq);
+	else /* Delay to ensure h2g completes */
+		delay_for_h2g();
+
+	return ret;
+}
+
+static int live_slpc_clamp_min(void *arg)
+{
+	struct drm_i915_private *i915 = arg;
+	struct intel_gt *gt = &i915->gt;
+	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;
+	int err = 0;
+
+	if (!intel_uc_uses_guc_slpc(&gt->uc))
+		return 0;
+
+	if (igt_spinner_init(&spin, gt))
+		return -ENOMEM;
+
+	if (intel_guc_slpc_get_max_freq(slpc, &slpc_max_freq)) {
+		pr_err("Could not get SLPC max freq\n");
+		return -EIO;
+	}
+
+	if (intel_guc_slpc_get_min_freq(slpc, &slpc_min_freq)) {
+		pr_err("Could not get SLPC min freq\n");
+		return -EIO;
+	}
+
+	if (slpc_min_freq == slpc_max_freq) {
+		pr_err("Min/Max are fused to the same value\n");
+		return -EINVAL;
+	}
+
+	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;
+
+		if (!intel_engine_can_store_dword(engine))
+			continue;
+
+		/* 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;
+			}
+
+			i915_request_add(rq);
+
+			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;
+			}
+
+			/* Wait for GuC to detect business and raise
+			 * requested frequency if necessary.
+			 */
+			delay_for_h2g();
+
+			req_freq = intel_rps_read_punit_req_frequency(rps);
+
+			/* 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;
+			}
+
+			act_freq =  intel_rps_read_actual_frequency(rps);
+			if (act_freq > max_act_freq)
+				max_act_freq = act_freq;
+
+			igt_spinner_end(&spin);
+			st_engine_heartbeat_enable(engine);
+		}
+
+		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) {
+			pr_err("Actual freq did not rise above min\n");
+			err = -EINVAL;
+		}
+
+		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)
+{
+	struct drm_i915_private *i915 = arg;
+	struct intel_gt *gt = &i915->gt;
+	struct intel_guc_slpc *slpc;
+	struct intel_rps *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;
+
+	if (!intel_uc_uses_guc_slpc(&gt->uc))
+		return 0;
+
+	if (igt_spinner_init(&spin, gt))
+		return -ENOMEM;
+
+	if (intel_guc_slpc_get_max_freq(slpc, &slpc_max_freq)) {
+		pr_err("Could not get SLPC max freq\n");
+		return -EIO;
+	}
+
+	if (intel_guc_slpc_get_min_freq(slpc, &slpc_min_freq)) {
+		pr_err("Could not get SLPC min freq\n");
+		return -EIO;
+	}
+
+	if (slpc_min_freq == slpc_max_freq) {
+		pr_err("Min/Max are fused to the same value\n");
+		return -EINVAL;
+	}
+
+	intel_gt_pm_wait_for_idle(gt);
+	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;
+
+		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;
+			}
+
+			i915_request_add(rq);
+
+			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;
+			}
+
+			delay_for_h2g();
+
+			/* Verify that SWREQ indeed was set to specific value */
+			req_freq = intel_rps_read_punit_req_frequency(rps);
+
+			/* 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);
+				igt_spinner_end(&spin);
+				st_engine_heartbeat_enable(engine);
+				err = -EINVAL;
+				break;
+			}
+
+			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;
+		}
+
+		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) {
+			pr_err("Actual freq did not rise above min\n");
+			err = -EINVAL;
+		}
+
+		if (igt_flush_test(gt->i915)) {
+			err = -EIO;
+			break;
+		}
+
+		if (err)
+			break;
+	}
+
+	/* Restore min/max freq */
+	slpc_set_max_freq(slpc, slpc_max_freq);
+	slpc_set_min_freq(slpc, slpc_min_freq);
+
+	intel_gt_pm_put(gt);
+	igt_spinner_fini(&spin);
+	intel_gt_pm_wait_for_idle(gt);
+
+	return err;
+}
+
+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),
+	};
+
+	if (intel_gt_is_wedged(&i915->gt))
+		return 0;
+
+	return i915_live_subtests(tests, i915);
+}

drivers/gpu/drm/i915/selftests/i915_live_selftests.h

@@ -47,5 +47,6 @@ selftest(hangcheck, intel_hangcheck_live_selftests)
 selftest(execlists, intel_execlists_live_selftests)
 selftest(ring_submission, intel_ring_submission_live_selftests)
 selftest(perf, i915_perf_live_selftests)
+selftest(slpc, intel_slpc_live_selftests)
 /* Here be dragons: keep last to run last! */
 selftest(late_gt_pm, intel_gt_pm_late_selftests)