drm/ttm/tests: Add tests for ttm_pool

Add KUnit tests that exercise page allocation using page pools
and freeing pages, either by returning them to the pool or
freeing them. Add a basic test for ttm_pool cleanup. Introduce
helpers to create a dummy ttm_buffer_object.
Signed-off-by: Karolina Stolarek <karolina.stolarek@intel.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
Link: https://patchwork.freedesktop.org/patch/msgid/427ea373357d0b6cb376c9d7ebc33c930bf1d28a.1691487006.git.karolina.stolarek@intel.comSigned-off-by: Christian König <christian.koenig@amd.com>

drivers/gpu/drm/ttm/tests/Makefile

@@ -2,4 +2,5 @@
 
 obj-$(CONFIG_DRM_TTM_KUNIT_TEST) += \
         ttm_device_test.o \
+        ttm_pool_test.o \
         ttm_kunit_helpers.o

drivers/gpu/drm/ttm/tests/ttm_kunit_helpers.c

@@ -25,6 +25,23 @@ int ttm_device_kunit_init(struct ttm_test_devices *priv,
 }
 EXPORT_SYMBOL_GPL(ttm_device_kunit_init);
 
+struct ttm_buffer_object *ttm_bo_kunit_init(struct kunit *test,
+					    struct ttm_test_devices *devs,
+					    size_t size)
+{
+	struct drm_gem_object gem_obj = { .size = size };
+	struct ttm_buffer_object *bo;
+
+	bo = kunit_kzalloc(test, sizeof(*bo), GFP_KERNEL);
+	KUNIT_ASSERT_NOT_NULL(test, bo);
+
+	bo->base = gem_obj;
+	bo->bdev = devs->ttm_dev;
+
+	return bo;
+}
+EXPORT_SYMBOL_GPL(ttm_bo_kunit_init);
+
 struct ttm_test_devices *ttm_test_devices_basic(struct kunit *test)
 {
 	struct ttm_test_devices *devs;

drivers/gpu/drm/ttm/tests/ttm_kunit_helpers.h

@@ -7,6 +7,7 @@
 
 #include <drm/drm_drv.h>
 #include <drm/ttm/ttm_device.h>
+#include <drm/ttm/ttm_bo.h>
 
 #include <drm/drm_kunit_helpers.h>
 #include <kunit/test.h>
@@ -24,6 +25,9 @@ int ttm_device_kunit_init(struct ttm_test_devices *priv,
 			  struct ttm_device *ttm,
 			  bool use_dma_alloc,
 			  bool use_dma32);
+struct ttm_buffer_object *ttm_bo_kunit_init(struct kunit *test,
+					    struct ttm_test_devices *devs,
+					    size_t size);
 
 struct ttm_test_devices *ttm_test_devices_basic(struct kunit *test);
 struct ttm_test_devices *ttm_test_devices_all(struct kunit *test);