drm/amdgpu/display: Implement functions to let DC allocate GPU memory

[Why]
DC needs to communicate with PM FW through GPU memory. In order
to do so we need to be able to allocate memory from within DC.

[How]
Call amdgpu_bo_create_kernel to allocate GPU memory and use a
list in amdgpu_display_manager to track our allocations so we
can clean them up later.
Signed-off-by: Harry Wentland <harry.wentland@amd.com>
Signed-off-by: Zhan Liu <zhan.liu@amd.com>
Reviewed-by: Charlene Liu <charlene.liu@amd.com>
Acked-by: Zhan Liu <zhan.liu@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c

@@ -1086,6 +1086,7 @@ static int amdgpu_dm_init(struct amdgpu_device *adev)
 
 	init_data.flags.power_down_display_on_boot = true;
 
+	INIT_LIST_HEAD(&adev->dm.da_list);
 	/* Display Core create. */
 	adev->dm.dc = dc_create(&init_data);
 

drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.h

@@ -132,6 +132,16 @@ struct amdgpu_dm_backlight_caps {
 	bool aux_support;
 };
 
+/**
+ * struct dal_allocation - Tracks mapped FB memory for SMU communication
+ */
+struct dal_allocation {
+	struct list_head list;
+	struct amdgpu_bo *bo;
+	void *cpu_ptr;
+	u64 gpu_addr;
+};
+
 /**
  * struct amdgpu_display_manager - Central amdgpu display manager device
  *
@@ -385,6 +395,12 @@ struct amdgpu_display_manager {
 	 */
 	struct amdgpu_encoder mst_encoders[AMDGPU_DM_MAX_CRTC];
 	bool force_timing_sync;
+	/**
+	 * @da_list:
+	 *
+	 * DAL fb memory allocation list, for communication with SMU.
+	 */
+	struct list_head da_list;
 };
 
 enum dsc_clock_force_state {

drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c

@@ -652,8 +652,31 @@ void *dm_helpers_allocate_gpu_mem(
 		size_t size,
 		long long *addr)
 {
-	// TODO
-	return NULL;
+	struct amdgpu_device *adev = ctx->driver_context;
+	struct dal_allocation *da;
+	u32 domain = (type == DC_MEM_ALLOC_TYPE_GART) ?
+		AMDGPU_GEM_DOMAIN_GTT : AMDGPU_GEM_DOMAIN_VRAM;
+	int ret;
+
+	da = kzalloc(sizeof(struct dal_allocation), GFP_KERNEL);
+	if (!da)
+		return NULL;
+
+	ret = amdgpu_bo_create_kernel(adev, size, PAGE_SIZE,
+				      domain, &da->bo,
+				      &da->gpu_addr, &da->cpu_ptr);
+
+	*addr = da->gpu_addr;
+
+	if (ret) {
+		kfree(da);
+		return NULL;
+	}
+
+	/* add da to list in dm */
+	list_add(&da->list, &adev->dm.da_list);
+
+	return da->cpu_ptr;
 }
 
 void dm_helpers_free_gpu_mem(
@@ -661,7 +684,18 @@ void dm_helpers_free_gpu_mem(
 		enum dc_gpu_mem_alloc_type type,
 		void *pvMem)
 {
-	// TODO
+	struct amdgpu_device *adev = ctx->driver_context;
+	struct dal_allocation *da;
+
+	/* walk the da list in DM */
+	list_for_each_entry(da, &adev->dm.da_list, list) {
+		if (pvMem == da->cpu_ptr) {
+			amdgpu_bo_free_kernel(&da->bo, &da->gpu_addr, &da->cpu_ptr);
+			list_del(&da->list);
+			kfree(da);
+			break;
+		}
+	}
 }
 
 bool dm_helpes_dmub_outbox0_interrupt_control(struct dc_context *ctx, bool enable)