drm/radeon: Add module param to control SI support

If AMDGPU supports SI, add a module parameter to control SI
support in radeon. It's on by default in radeon, while it will be
off by default in AMDGPU as long as SI support is experimental.
Signed-off-by: Felix Kuehling <Felix.Kuehling@amd.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
Acked-by: Michel Dänzer <michel.daenzer@amd.com>

drivers/gpu/drm/radeon/radeon.h

@@ -116,6 +116,9 @@ extern int radeon_mst;
 extern int radeon_uvd;
 extern int radeon_vce;
 
+#ifdef CONFIG_DRM_AMDGPU_SI
+extern int radeon_si_support;
+#endif
 #ifdef CONFIG_DRM_AMDGPU_CIK
 extern int radeon_cik_support;
 #endif

drivers/gpu/drm/radeon/radeon_drv.c

@@ -295,6 +295,12 @@ module_param_named(uvd, radeon_uvd, int, 0444);
 MODULE_PARM_DESC(vce, "vce enable/disable vce support (1 = enable, 0 = disable)");
 module_param_named(vce, radeon_vce, int, 0444);
 
+#ifdef CONFIG_DRM_AMDGPU_SI
+int radeon_si_support = 1;
+MODULE_PARM_DESC(si_support, "SI support (1 = enabled (default), 0 = disabled)");
+module_param_named(si_support, radeon_si_support, int, 0444);
+#endif
+
 #ifdef CONFIG_DRM_AMDGPU_CIK
 int radeon_cik_support = 0;
 MODULE_PARM_DESC(cik_support, "CIK support (1 = enabled, 0 = disabled (default))");

drivers/gpu/drm/radeon/radeon_kms.c

@@ -98,6 +98,20 @@ int radeon_driver_load_kms(struct drm_device *dev, unsigned long flags)
 	struct radeon_device *rdev;
 	int r, acpi_status;
 
+#ifdef CONFIG_DRM_AMDGPU_SI
+	if (!radeon_si_support) {
+		switch (flags & RADEON_FAMILY_MASK) {
+		case CHIP_TAHITI:
+		case CHIP_PITCAIRN:
+		case CHIP_VERDE:
+		case CHIP_OLAND:
+		case CHIP_HAINAN:
+			dev_info(dev->dev,
+				 "SI support disabled by module param\n");
+			return -ENODEV;
+		}
+	}
+#endif
 #ifdef CONFIG_DRM_AMDGPU_CIK
 	if (!radeon_cik_support) {
 		switch (flags & RADEON_FAMILY_MASK) {