[PATCH 04/15] drm: Add drm_gem_ttm_fill_create_dumb() to create dumb buffers

[Thomas Zimmermann]

The helper function drm_gem_ttm_fill_create_dumb() implements most of
struct drm_driver.dumb_create() for GEM TTM buffer objects. It's not a
full implemenation of the callback, as several driver-specific parameters
are still required.

Signed-off-by: Thomas Zimmermann <tzimmermann at suse.de>
---
 drivers/gpu/drm/drm_gem_ttm_helper.c | 62 ++++++++++++++++++++++++++++
 include/drm/drm_gem_ttm_helper.h     |  8 ++++
 2 files changed, 70 insertions(+)

diff --git a/drivers/gpu/drm/drm_gem_ttm_helper.c b/drivers/gpu/drm/drm_gem_ttm_helper.c
index d4950517e357..a2306e27db13 100644
--- a/drivers/gpu/drm/drm_gem_ttm_helper.c
+++ b/drivers/gpu/drm/drm_gem_ttm_helper.c
@@ -1,6 +1,7 @@
 /* SPDX-License-Identifier: GPL-2.0-or-later */
 
 #include <drm/drm_gem_ttm_helper.h>
+#include <drm/drm_mode.h>
 #include <drm/ttm/ttm_page_alloc.h>
 
 /**
@@ -366,6 +367,67 @@ bool drm_is_gem_ttm(struct ttm_buffer_object *bo)
 }
 EXPORT_SYMBOL(drm_is_gem_ttm);
 
+/**
+ * drm_gem_ttm_fill_create_dumb() - \
+	Helper for implementing struct drm_driver.dumb_create
+ * @file:		the DRM file
+ * @dev:		the DRM device
+ * @bdev:		the TTM BO device managing the buffer object
+ * @pg_align:		the buffer's alignment in multiples of the page size
+ * @interruptible:	sleep interruptible if waiting for memory
+ * @args:		the arguments as provided to \
+				struct drm_driver.dumb_create
+ *
+ * This helper function fills struct drm_mode_create_dumb, which is used
+ * by struct drm_driver.dumb_create. Implementations of this interface
+ * should forwards their arguments to this helper; plus the driver-specific
+ * parameters.
+ *
+ * Returns:
+ * 0 on success, or
+ * a negative error code otherwise.
+ */
+int drm_gem_ttm_fill_create_dumb(struct drm_file *file,
+				 struct drm_device *dev,
+				 struct ttm_bo_device *bdev,
+				 uint32_t pg_align,
+				 bool interruptible,
+				 struct drm_mode_create_dumb *args)
+{
+	size_t pitch, size;
+	struct drm_gem_ttm_object *gbo;
+	int ret;
+	u32 handle;
+
+	pitch = args->width * ((args->bpp + 7) / 8);
+	size = pitch * args->height;
+
+	size = roundup(size, PAGE_SIZE);
+	if (!size)
+		return -EINVAL;
+
+	gbo = drm_gem_ttm_create(dev, bdev, size, pg_align, interruptible);
+	if (IS_ERR(gbo))
+		return PTR_ERR(gbo);
+
+	ret = drm_gem_handle_create(file, &gbo->gem, &handle);
+	if (ret)
+		goto err_drm_gem_object_put_unlocked;
+
+	drm_gem_object_put_unlocked(&gbo->gem);
+
+	args->pitch = pitch;
+	args->size = size;
+	args->handle = handle;
+
+	return 0;
+
+err_drm_gem_object_put_unlocked:
+	drm_gem_object_put_unlocked(&gbo->gem);
+	return ret;
+}
+EXPORT_SYMBOL(drm_gem_ttm_fill_create_dumb);
+
 /*
  * Helpers for struct ttm_bo_driver
  */
diff --git a/include/drm/drm_gem_ttm_helper.h b/include/drm/drm_gem_ttm_helper.h
index edc2093588ff..3918dfca1d58 100644
--- a/include/drm/drm_gem_ttm_helper.h
+++ b/include/drm/drm_gem_ttm_helper.h
@@ -8,6 +8,7 @@
 #include <drm/ttm/ttm_placement.h>
 #include <linux/kernel.h> /* for container_of() */
 
+struct drm_mode_create_dumb;
 struct filp;
 
 /*
@@ -88,6 +89,13 @@ void drm_gem_ttm_kunmap(struct drm_gem_ttm_object *gbo);
 
 bool drm_is_gem_ttm(struct ttm_buffer_object *bo);
 
+int drm_gem_ttm_fill_create_dumb(struct drm_file *file,
+				 struct drm_device *dev,
+				 struct ttm_bo_device *bdev,
+				 uint32_t pg_align,
+				 bool interruptible,
+				 struct drm_mode_create_dumb *args);
+
 /*
  * Helpers for struct ttm_bo_driver
  */
-- 
2.21.0