This function can be used by drivers that need to mmap dumb buffers created with non-coherent backing memory.
Signed-off-by: Paul Cercueil paul@crapouillou.net --- drivers/gpu/drm/drm_gem_cma_helper.c | 39 ++++++++++++++++++++++++++++ include/drm/drm_gem_cma_helper.h | 2 ++ 2 files changed, 41 insertions(+)
diff --git a/drivers/gpu/drm/drm_gem_cma_helper.c b/drivers/gpu/drm/drm_gem_cma_helper.c index 3bdd67795e20..4ed63f4896bd 100644 --- a/drivers/gpu/drm/drm_gem_cma_helper.c +++ b/drivers/gpu/drm/drm_gem_cma_helper.c @@ -387,6 +387,45 @@ int drm_gem_cma_mmap(struct file *filp, struct vm_area_struct *vma) } EXPORT_SYMBOL_GPL(drm_gem_cma_mmap);
+/** + * drm_gem_cma_mmap_noncoherent - memory-map a CMA GEM object with + * non-coherent cache attribute + * @filp: file object + * @vma: VMA for the area to be mapped + * + * Just like drm_gem_cma_mmap, but for a GEM object backed by non-coherent + * memory. + * + * Returns: + * 0 on success or a negative error code on failure. + */ +int drm_gem_cma_mmap_noncoherent(struct file *filp, struct vm_area_struct *vma) +{ + struct drm_gem_cma_object *cma_obj; + int ret; + + ret = drm_gem_mmap(filp, vma); + if (ret) + return ret; + + cma_obj = to_drm_gem_cma_obj(vma->vm_private_data); + + /* + * Clear the VM_PFNMAP flag that was set by drm_gem_mmap(), and set the + * vm_pgoff (used as a fake buffer offset by DRM) to 0 as we want to map + * the whole buffer. + */ + vma->vm_flags &= ~VM_PFNMAP; + vma->vm_pgoff = 0; + vma->vm_page_prot = vm_get_page_prot(vma->vm_flags); + + return remap_pfn_range(vma, vma->vm_start, + cma_obj->paddr >> PAGE_SHIFT, + vma->vm_end - vma->vm_start, + vma->vm_page_prot); +} +EXPORT_SYMBOL_GPL(drm_gem_cma_mmap_noncoherent); + #ifndef CONFIG_MMU /** * drm_gem_cma_get_unmapped_area - propose address for mapping in noMMU cases diff --git a/include/drm/drm_gem_cma_helper.h b/include/drm/drm_gem_cma_helper.h index d0e6a1cd0950..6b01ad5581c3 100644 --- a/include/drm/drm_gem_cma_helper.h +++ b/include/drm/drm_gem_cma_helper.h @@ -83,6 +83,8 @@ int drm_gem_cma_dumb_create_noncoherent(struct drm_file *file_priv, /* set vm_flags and we can change the VM attribute to other one at here */ int drm_gem_cma_mmap(struct file *filp, struct vm_area_struct *vma);
+int drm_gem_cma_mmap_noncoherent(struct file *filep, struct vm_area_struct *vma); + /* allocate physical memory */ struct drm_gem_cma_object *drm_gem_cma_create(struct drm_device *drm, size_t size);