drm_gem_cma_prime_vmap — map a CMA GEM object into the kernel's virtual address space
| void * drm_gem_cma_prime_vmap ( | struct drm_gem_object * obj ); | 
   This function maps a buffer exported via DRM PRIME into the kernel's
   virtual address space. Since the CMA buffers are already mapped into the
   kernel virtual address space this simply returns the cached virtual
   address. Drivers using the CMA helpers should set this as their DRM
   driver's ->gem_prime_vmap callback.