drm/radeon/kms: add support for compute rings in CS ioctl on SI

Very basic implementation for picking the ring priority.
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>
Signed-off-by: NDave Airlie <airlied@redhat.com>

drivers/gpu/drm/radeon/radeon_cs.c

@@ -103,8 +103,13 @@ static int radeon_cs_get_ring(struct radeon_cs_parser *p, u32 ring, s32 priority
 		p->ring = RADEON_RING_TYPE_GFX_INDEX;
 		break;
 	case RADEON_CS_RING_COMPUTE:
-		/* for now */
-		p->ring = RADEON_RING_TYPE_GFX_INDEX;
+		if (p->rdev->family >= CHIP_TAHITI) {
+			if (p->priority > 0)
+				p->ring = CAYMAN_RING_TYPE_CP1_INDEX;
+			else
+				p->ring = CAYMAN_RING_TYPE_CP2_INDEX;
+		} else
+			p->ring = RADEON_RING_TYPE_GFX_INDEX;
 		break;
 	}
 	return 0;