[PATCH 4/7] drm/cma: Introduce drm_gem_cma_dumb_create_internal()

[Thierry Reding]

From: Thierry Reding <treding at nvidia.com>

This function is similar to drm_gem_cma_dumb_create() but targetted at
kernel internal users so that they can override the pitch and size
requirements of the dumb buffer.

It is important to make this difference because the IOCTL says that the
pitch and size fields are to be considered outputs and therefore should
not be used in computations of the framebuffer size. Internal users may
still want to use this code to avoid duplication and at the same time
pass on additional, driver-specific restrictions on the pitch and size.

While at it, convert the R-Car DU driver, the single user that overrides
the pitch, to use the new internal helper.

Signed-off-by: Thierry Reding <treding at nvidia.com>
---
 drivers/gpu/drm/drm_gem_cma_helper.c  | 33 ++++++++++++++++++++++++++++-----
 drivers/gpu/drm/rcar-du/rcar_du_kms.c |  2 +-
 include/drm/drm_gem_cma_helper.h      |  5 +++++
 3 files changed, 34 insertions(+), 6 deletions(-)

diff --git a/drivers/gpu/drm/drm_gem_cma_helper.c b/drivers/gpu/drm/drm_gem_cma_helper.c
index 55306be1f8f7..c55986566f0c 100644
--- a/drivers/gpu/drm/drm_gem_cma_helper.c
+++ b/drivers/gpu/drm/drm_gem_cma_helper.c
@@ -189,7 +189,7 @@ void drm_gem_cma_free_object(struct drm_gem_object *gem_obj)
 EXPORT_SYMBOL_GPL(drm_gem_cma_free_object);
 
 /**
- * drm_gem_cma_dumb_create - create a dumb buffer object
+ * drm_gem_cma_dumb_create_internal - create a dumb buffer object
  * @file_priv: DRM file-private structure to create the dumb buffer for
  * @drm: DRM device
  * @args: IOCTL data
@@ -199,12 +199,12 @@ EXPORT_SYMBOL_GPL(drm_gem_cma_free_object);
  *
  * Return: 0 on success or a negative error code on failure.
  */
-int drm_gem_cma_dumb_create(struct drm_file *file_priv,
-			    struct drm_device *drm,
-			    struct drm_mode_create_dumb *args)
+int drm_gem_cma_dumb_create_internal(struct drm_file *file_priv,
+				     struct drm_device *drm,
+				     struct drm_mode_create_dumb *args)
 {
+	unsigned int min_pitch = DIV_ROUND_UP(args->width * args->bpp, 8);
 	struct drm_gem_cma_object *cma_obj;
-	int min_pitch = DIV_ROUND_UP(args->width * args->bpp, 8);
 
 	if (args->pitch < min_pitch)
 		args->pitch = min_pitch;
@@ -216,6 +216,29 @@ int drm_gem_cma_dumb_create(struct drm_file *file_priv,
 						 &args->handle);
 	return PTR_ERR_OR_ZERO(cma_obj);
 }
+EXPORT_SYMBOL_GPL(drm_gem_cma_dumb_create_internal);
+
+/**
+ * drm_gem_cma_dumb_create - create a dumb buffer object
+ * @file_priv: DRM file-private structure to create the dumb buffer for
+ * @drm: DRM device
+ * @args: IOCTL data
+ *
+ * Return: 0 on success or a negative error code on failure.
+ */
+int drm_gem_cma_dumb_create(struct drm_file *file_priv,
+			    struct drm_device *drm,
+			    struct drm_mode_create_dumb *args)
+{
+	struct drm_gem_cma_object *cma_obj;
+
+	args->pitch = DIV_ROUND_UP(args->width * args->bpp, 8);
+	args->size = args->pitch * args->height;
+
+	cma_obj = drm_gem_cma_create_with_handle(file_priv, drm, args->size,
+						 &args->handle);
+	return PTR_ERR_OR_ZERO(cma_obj);
+}
 EXPORT_SYMBOL_GPL(drm_gem_cma_dumb_create);
 
 /**
diff --git a/drivers/gpu/drm/rcar-du/rcar_du_kms.c b/drivers/gpu/drm/rcar-du/rcar_du_kms.c
index 6c24ad7d03ef..5329491e32c3 100644
--- a/drivers/gpu/drm/rcar-du/rcar_du_kms.c
+++ b/drivers/gpu/drm/rcar-du/rcar_du_kms.c
@@ -128,7 +128,7 @@ int rcar_du_dumb_create(struct drm_file *file, struct drm_device *dev,
 
 	args->pitch = roundup(max(args->pitch, min_pitch), align);
 
-	return drm_gem_cma_dumb_create(file, dev, args);
+	return drm_gem_cma_dumb_create_internal(file, dev, args);
 }
 
 static struct drm_framebuffer *
diff --git a/include/drm/drm_gem_cma_helper.h b/include/drm/drm_gem_cma_helper.h
index 873d4eb7f125..acd6af8a8e67 100644
--- a/include/drm/drm_gem_cma_helper.h
+++ b/include/drm/drm_gem_cma_helper.h
@@ -30,6 +30,11 @@ to_drm_gem_cma_obj(struct drm_gem_object *gem_obj)
 void drm_gem_cma_free_object(struct drm_gem_object *gem_obj);
 
 /* create memory region for DRM framebuffer */
+int drm_gem_cma_dumb_create_internal(struct drm_file *file_priv,
+				     struct drm_device *drm,
+				     struct drm_mode_create_dumb *args);
+
+/* create memory region for DRM framebuffer */
 int drm_gem_cma_dumb_create(struct drm_file *file_priv,
 			    struct drm_device *drm,
 			    struct drm_mode_create_dumb *args);
-- 
2.1.3