drm/i915: Add unit tests for the breadcrumb rbtree, insert/remove

First retroactive test, make sure that the waiters are in global seqno
order after random inserts and removals.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20170213171558.20942-3-chris@chris-wilson.co.uk

drivers/gpu/drm/i915/intel_breadcrumbs.c

@@ -107,6 +107,18 @@ static void __intel_breadcrumbs_enable_irq(struct intel_breadcrumbs *b)
 	if (b->rpm_wakelock)
 		return;
 
+	if (I915_SELFTEST_ONLY(b->mock)) {
+		/* For our mock objects we want to avoid interaction
+		 * with the real hardware (which is not set up). So
+		 * we simply pretend we have enabled the powerwell
+		 * and the irq, and leave it up to the mock
+		 * implementation to call intel_engine_wakeup()
+		 * itself when it wants to simulate a user interrupt,
+		 */
+		b->rpm_wakelock = true;
+		return;
+	}
+
 	/* Since we are waiting on a request, the GPU should be busy
 	 * and should have its own rpm reference. For completeness,
 	 * record an rpm reference for ourselves to cover the
@@ -142,6 +154,11 @@ static void __intel_breadcrumbs_disable_irq(struct intel_breadcrumbs *b)
 	if (!b->rpm_wakelock)
 		return;
 
+	if (I915_SELFTEST_ONLY(b->mock)) {
+		b->rpm_wakelock = false;
+		return;
+	}
+
 	if (b->irq_enabled) {
 		irq_disable(engine);
 		b->irq_enabled = false;
@@ -664,3 +681,7 @@ unsigned int intel_breadcrumbs_busy(struct drm_i915_private *i915)
 
 	return mask;
 }
+
+#if IS_ENABLED(CONFIG_DRM_I915_SELFTEST)
+#include "selftests/intel_breadcrumbs.c"
+#endif

drivers/gpu/drm/i915/intel_engine_cs.c

@@ -524,3 +524,7 @@ void intel_engine_get_instdone(struct intel_engine_cs *engine,
 		break;
 	}
 }
+
+#if IS_ENABLED(CONFIG_DRM_I915_SELFTEST)
+#include "selftests/mock_engine.c"
+#endif

drivers/gpu/drm/i915/intel_ringbuffer.h

@@ -5,6 +5,7 @@
 #include "i915_gem_batch_pool.h"
 #include "i915_gem_request.h"
 #include "i915_gem_timeline.h"
+#include "i915_selftest.h"
 
 #define I915_CMD_HASH_ORDER 9
 
@@ -249,6 +250,7 @@ struct intel_engine_cs {
 
 		bool irq_enabled : 1;
 		bool rpm_wakelock : 1;
+		I915_SELFTEST_DECLARE(bool mock : 1);
 	} breadcrumbs;
 
 	/*

drivers/gpu/drm/i915/selftests/i915_mock_selftests.h

@@ -10,3 +10,4 @@
  */
 selftest(sanitycheck, i915_mock_sanitycheck) /* keep first (igt selfcheck) */
 selftest(scatterlist, scatterlist_mock_selftests)
+selftest(breadcrumbs, intel_breadcrumbs_mock_selftests)

drivers/gpu/drm/i915/selftests/intel_breadcrumbs.c

@@ -0,0 +1,172 @@
+/*
+ * Copyright © 2016 Intel Corporation
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+ * IN THE SOFTWARE.
+ *
+ */
+
+#include "../i915_selftest.h"
+#include "i915_random.h"
+
+#include "mock_engine.h"
+
+static int check_rbtree(struct intel_engine_cs *engine,
+			const unsigned long *bitmap,
+			const struct intel_wait *waiters,
+			const int count)
+{
+	struct intel_breadcrumbs *b = &engine->breadcrumbs;
+	struct rb_node *rb;
+	int n;
+
+	if (&b->first_wait->node != rb_first(&b->waiters)) {
+		pr_err("First waiter does not match first element of wait-tree\n");
+		return -EINVAL;
+	}
+
+	n = find_first_bit(bitmap, count);
+	for (rb = rb_first(&b->waiters); rb; rb = rb_next(rb)) {
+		struct intel_wait *w = container_of(rb, typeof(*w), node);
+		int idx = w - waiters;
+
+		if (!test_bit(idx, bitmap)) {
+			pr_err("waiter[%d, seqno=%d] removed but still in wait-tree\n",
+			       idx, w->seqno);
+			return -EINVAL;
+		}
+
+		if (n != idx) {
+			pr_err("waiter[%d, seqno=%d] does not match expected next element in tree [%d]\n",
+			       idx, w->seqno, n);
+			return -EINVAL;
+		}
+
+		n = find_next_bit(bitmap, count, n + 1);
+	}
+
+	return 0;
+}
+
+static int check_rbtree_empty(struct intel_engine_cs *engine)
+{
+	struct intel_breadcrumbs *b = &engine->breadcrumbs;
+
+	if (b->first_wait) {
+		pr_err("Empty breadcrumbs still has a waiter\n");
+		return -EINVAL;
+	}
+
+	if (!RB_EMPTY_ROOT(&b->waiters)) {
+		pr_err("Empty breadcrumbs, but wait-tree not empty\n");
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static int igt_random_insert_remove(void *arg)
+{
+	const u32 seqno_bias = 0x1000;
+	I915_RND_STATE(prng);
+	struct intel_engine_cs *engine = arg;
+	struct intel_wait *waiters;
+	const int count = 4096;
+	unsigned int *order;
+	unsigned long *bitmap;
+	int err = -ENOMEM;
+	int n;
+
+	mock_engine_reset(engine);
+
+	waiters = drm_malloc_gfp(count, sizeof(*waiters), GFP_TEMPORARY);
+	if (!waiters)
+		goto out_engines;
+
+	bitmap = kcalloc(DIV_ROUND_UP(count, BITS_PER_LONG), sizeof(*bitmap),
+			 GFP_TEMPORARY);
+	if (!bitmap)
+		goto out_waiters;
+
+	order = i915_random_order(count, &prng);
+	if (!order)
+		goto out_bitmap;
+
+	for (n = 0; n < count; n++)
+		intel_wait_init(&waiters[n], seqno_bias + n);
+
+	err = check_rbtree(engine, bitmap, waiters, count);
+	if (err)
+		goto out_order;
+
+	/* Add and remove waiters into the rbtree in random order. At each
+	 * step, we verify that the rbtree is correctly ordered.
+	 */
+	for (n = 0; n < count; n++) {
+		int i = order[n];
+
+		intel_engine_add_wait(engine, &waiters[i]);
+		__set_bit(i, bitmap);
+
+		err = check_rbtree(engine, bitmap, waiters, count);
+		if (err)
+			goto out_order;
+	}
+
+	i915_random_reorder(order, count, &prng);
+	for (n = 0; n < count; n++) {
+		int i = order[n];
+
+		intel_engine_remove_wait(engine, &waiters[i]);
+		__clear_bit(i, bitmap);
+
+		err = check_rbtree(engine, bitmap, waiters, count);
+		if (err)
+			goto out_order;
+	}
+
+	err = check_rbtree_empty(engine);
+out_order:
+	kfree(order);
+out_bitmap:
+	kfree(bitmap);
+out_waiters:
+	drm_free_large(waiters);
+out_engines:
+	mock_engine_flush(engine);
+	return err;
+}
+
+int intel_breadcrumbs_mock_selftests(void)
+{
+	static const struct i915_subtest tests[] = {
+		SUBTEST(igt_random_insert_remove),
+	};
+	struct intel_engine_cs *engine;
+	int err;
+
+	engine = mock_engine("mock");
+	if (!engine)
+		return -ENOMEM;
+
+	err = i915_subtests(tests, engine);
+	kfree(engine);
+
+	return err;
+}

drivers/gpu/drm/i915/selftests/mock_engine.c

@@ -0,0 +1,55 @@
+/*
+ * Copyright © 2016 Intel Corporation
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+ * IN THE SOFTWARE.
+ *
+ */
+
+#include "mock_engine.h"
+
+struct intel_engine_cs *mock_engine(const char *name)
+{
+	struct intel_engine_cs *engine;
+	static int id;
+
+	engine = kzalloc(sizeof(*engine) + PAGE_SIZE, GFP_KERNEL);
+	if (!engine)
+		return NULL;
+
+	/* minimal engine setup for seqno */
+	engine->name = name;
+	engine->id = id++;
+	engine->status_page.page_addr = (void *)(engine + 1);
+
+	/* minimal breadcrumbs init */
+	spin_lock_init(&engine->breadcrumbs.lock);
+	engine->breadcrumbs.mock = true;
+
+	return engine;
+}
+
+void mock_engine_flush(struct intel_engine_cs *engine)
+{
+}
+
+void mock_engine_reset(struct intel_engine_cs *engine)
+{
+	intel_write_status_page(engine, I915_GEM_HWS_INDEX, 0);
+}

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

@@ -0,0 +1,32 @@
+/*
+ * Copyright © 2016 Intel Corporation
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+ * IN THE SOFTWARE.
+ *
+ */
+
+#ifndef __MOCK_ENGINE_H__
+#define __MOCK_ENGINE_H__
+
+struct intel_engine_cs *mock_engine(const char *name);
+void mock_engine_flush(struct intel_engine_cs *engine);
+void mock_engine_reset(struct intel_engine_cs *engine);
+
+#endif /* !__MOCK_ENGINE_H__ */