drm/vc4: Move mmap implementation into GEM object function

Moving vc4's mmap code from vc4_mmap() into a GEM object function
allows for the use drm_gem_mmap() and drm_gem_prime_mmap(). The content
of vc4_drm_fpos can then be generated by DEFINE_DRM_GEM_FOPS().

The actual mmap implementation is just a check if the BO is a validated
shader plus the default CMA mmap code.
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Acked-by: Maxime Ripard <mripard@kernel.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20210108140808.25775-4-tzimmermann@suse.de

drivers/gpu/drm/vc4/vc4_bo.c

@@ -704,19 +704,9 @@ static vm_fault_t vc4_fault(struct vm_fault *vmf)
 	return VM_FAULT_SIGBUS;
 }
 
-int vc4_mmap(struct file *filp, struct vm_area_struct *vma)
+static int vc4_gem_object_mmap(struct drm_gem_object *obj, struct vm_area_struct *vma)
 {
-	struct drm_gem_object *gem_obj;
-	unsigned long vm_pgoff;
-	struct vc4_bo *bo;
-	int ret;
-
-	ret = drm_gem_mmap(filp, vma);
-	if (ret)
-		return ret;
-
-	gem_obj = vma->vm_private_data;
-	bo = to_vc4_bo(gem_obj);
+	struct vc4_bo *bo = to_vc4_bo(obj);
 
 	if (bo->validated_shader && (vma->vm_flags & VM_WRITE)) {
 		DRM_DEBUG("mmaping of shader BOs for writing not allowed.\n");
@@ -730,45 +720,7 @@ int vc4_mmap(struct file *filp, struct vm_area_struct *vma)
 		return -EINVAL;
 	}
 
-	/*
-	 * 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;
-
-	/* This ->vm_pgoff dance is needed to make all parties happy:
-	 * - dma_mmap_wc() uses ->vm_pgoff as an offset within the allocated
-	 *   mem-region, hence the need to set it to zero (the value set by
-	 *   the DRM core is a virtual offset encoding the GEM object-id)
-	 * - the mmap() core logic needs ->vm_pgoff to be restored to its
-	 *   initial value before returning from this function because it
-	 *   encodes the  offset of this GEM in the dev->anon_inode pseudo-file
-	 *   and this information will be used when we invalidate userspace
-	 *   mappings  with drm_vma_node_unmap() (called from vc4_gem_purge()).
-	 */
-	vm_pgoff = vma->vm_pgoff;
-	vma->vm_pgoff = 0;
-	ret = dma_mmap_wc(bo->base.base.dev->dev, vma, bo->base.vaddr,
-			  bo->base.paddr, vma->vm_end - vma->vm_start);
-	vma->vm_pgoff = vm_pgoff;
-
-	if (ret)
-		drm_gem_vm_close(vma);
-
-	return ret;
-}
-
-int vc4_prime_mmap(struct drm_gem_object *obj, struct vm_area_struct *vma)
-{
-	struct vc4_bo *bo = to_vc4_bo(obj);
-
-	if (bo->validated_shader && (vma->vm_flags & VM_WRITE)) {
-		DRM_DEBUG("mmaping of shader BOs for writing not allowed.\n");
-		return -EINVAL;
-	}
-
-	return drm_gem_prime_mmap(obj, vma);
+	return drm_gem_cma_mmap(obj, vma);
 }
 
 static const struct vm_operations_struct vc4_vm_ops = {
@@ -782,6 +734,7 @@ static const struct drm_gem_object_funcs vc4_gem_object_funcs = {
 	.export = vc4_prime_export,
 	.get_sg_table = drm_gem_cma_get_sg_table,
 	.vmap = drm_gem_cma_vmap,
+	.mmap = vc4_gem_object_mmap,
 	.vm_ops = &vc4_vm_ops,
 };
 

drivers/gpu/drm/vc4/vc4_drv.c

@@ -140,17 +140,7 @@ static void vc4_close(struct drm_device *dev, struct drm_file *file)
 	kfree(vc4file);
 }
 
-static const struct file_operations vc4_drm_fops = {
-	.owner = THIS_MODULE,
-	.open = drm_open,
-	.release = drm_release,
-	.unlocked_ioctl = drm_ioctl,
-	.mmap = vc4_mmap,
-	.poll = drm_poll,
-	.read = drm_read,
-	.compat_ioctl = drm_compat_ioctl,
-	.llseek = noop_llseek,
-};
+DEFINE_DRM_GEM_FOPS(vc4_drm_fops);
 
 static const struct drm_ioctl_desc vc4_drm_ioctls[] = {
 	DRM_IOCTL_DEF_DRV(VC4_SUBMIT_CL, vc4_submit_cl_ioctl, DRM_RENDER_ALLOW),
@@ -193,7 +183,7 @@ static struct drm_driver vc4_drm_driver = {
 	.prime_handle_to_fd = drm_gem_prime_handle_to_fd,
 	.prime_fd_to_handle = drm_gem_prime_fd_to_handle,
 	.gem_prime_import_sg_table = vc4_prime_import_sg_table,
-	.gem_prime_mmap = vc4_prime_mmap,
+	.gem_prime_mmap = drm_gem_prime_mmap,
 
 	.dumb_create = vc4_dumb_create,
 

drivers/gpu/drm/vc4/vc4_drv.h

@@ -801,8 +801,6 @@ int vc4_get_hang_state_ioctl(struct drm_device *dev, void *data,
 			     struct drm_file *file_priv);
 int vc4_label_bo_ioctl(struct drm_device *dev, void *data,
 		       struct drm_file *file_priv);
-int vc4_mmap(struct file *filp, struct vm_area_struct *vma);
-int vc4_prime_mmap(struct drm_gem_object *obj, struct vm_area_struct *vma);
 struct drm_gem_object *vc4_prime_import_sg_table(struct drm_device *dev,
 						 struct dma_buf_attachment *attach,
 						 struct sg_table *sgt);