drm/cma-helper: Add drm_fb_cma_fbdev_init/fini()

Add functions drm_fb_cma_fbdev_init(), drm_fb_cma_fbdev_fini() and
drm_fb_cma_fbdev_init_with_funcs(). These functions relies on the fact
that the drm_fb_helper struct is stored in dev->drm_fb_helper_private
so drivers don't need to store it.

Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Noralf Trønnes <noralf@tronnes.org>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20171115142001.45358-3-noralf@tronnes.org

drivers/gpu/drm/drm_fb_cma_helper.c

@@ -23,6 +23,7 @@
 #include <drm/drm_gem_cma_helper.h>
 #include <drm/drm_gem_framebuffer_helper.h>
 #include <drm/drm_fb_cma_helper.h>
+#include <drm/drm_print.h>
 #include <linux/module.h>
 
 #define DEFAULT_FBDEFIO_DELAY_MS 50
@@ -42,7 +43,7 @@ struct drm_fbdev_cma {
  * callback function to create a cma backed framebuffer.
  *
  * An fbdev framebuffer backed by cma is also available by calling
- * drm_fbdev_cma_init(). drm_fbdev_cma_fini() tears it down.
+ * drm_fb_cma_fbdev_init(). drm_fb_cma_fbdev_fini() tears it down.
  * If the &drm_framebuffer_funcs.dirty callback is set, fb_deferred_io will be
  * set up automatically. &drm_framebuffer_funcs.dirty is called by
  * drm_fb_helper_deferred_io() in process context (&struct delayed_work).
@@ -68,7 +69,7 @@ struct drm_fbdev_cma {
  *
  * Initialize::
  *
- *     fbdev = drm_fbdev_cma_init_with_funcs(dev, 16,
+ *     fbdev = drm_fb_cma_fbdev_init_with_funcs(dev, 16,
  *                                           dev->mode_config.num_crtc,
  *                                           dev->mode_config.num_connector,
  *                                           &driver_fb_funcs);
@@ -256,7 +257,7 @@ drm_fbdev_cma_create(struct drm_fb_helper *helper,
 	fbi->screen_size = size;
 	fbi->fix.smem_len = size;
 
-	if (fbdev_cma->fb_funcs->dirty) {
+	if (fb->funcs->dirty) {
 		ret = drm_fbdev_cma_defio_init(fbi, obj);
 		if (ret)
 			goto err_cma_destroy;
@@ -277,6 +278,118 @@ static const struct drm_fb_helper_funcs drm_fb_cma_helper_funcs = {
 	.fb_probe = drm_fbdev_cma_create,
 };
 
+/**
+ * drm_fb_cma_fbdev_init_with_funcs() - Allocate and initialize fbdev emulation
+ * @dev: DRM device
+ * @preferred_bpp: Preferred bits per pixel for the device.
+ *                 @dev->mode_config.preferred_depth is used if this is zero.
+ * @max_conn_count: Maximum number of connectors.
+ *                  @dev->mode_config.num_connector is used if this is zero.
+ * @funcs: Framebuffer functions, in particular a custom dirty() callback.
+ *         Can be NULL.
+ *
+ * Returns:
+ * Zero on success or negative error code on failure.
+ */
+int drm_fb_cma_fbdev_init_with_funcs(struct drm_device *dev,
+	unsigned int preferred_bpp, unsigned int max_conn_count,
+	const struct drm_framebuffer_funcs *funcs)
+{
+	struct drm_fbdev_cma *fbdev_cma;
+	struct drm_fb_helper *fb_helper;
+	int ret;
+
+	if (!preferred_bpp)
+		preferred_bpp = dev->mode_config.preferred_depth;
+	if (!preferred_bpp)
+		preferred_bpp = 32;
+
+	if (!max_conn_count)
+		max_conn_count = dev->mode_config.num_connector;
+
+	fbdev_cma = kzalloc(sizeof(*fbdev_cma), GFP_KERNEL);
+	if (!fbdev_cma)
+		return -ENOMEM;
+
+	fbdev_cma->fb_funcs = funcs;
+	fb_helper = &fbdev_cma->fb_helper;
+
+	drm_fb_helper_prepare(dev, fb_helper, &drm_fb_cma_helper_funcs);
+
+	ret = drm_fb_helper_init(dev, fb_helper, max_conn_count);
+	if (ret < 0) {
+		DRM_DEV_ERROR(dev->dev, "Failed to initialize fbdev helper.\n");
+		goto err_free;
+	}
+
+	ret = drm_fb_helper_single_add_all_connectors(fb_helper);
+	if (ret < 0) {
+		DRM_DEV_ERROR(dev->dev, "Failed to add connectors.\n");
+		goto err_drm_fb_helper_fini;
+	}
+
+	ret = drm_fb_helper_initial_config(fb_helper, preferred_bpp);
+	if (ret < 0) {
+		DRM_DEV_ERROR(dev->dev, "Failed to set fbdev configuration.\n");
+		goto err_drm_fb_helper_fini;
+	}
+
+	return 0;
+
+err_drm_fb_helper_fini:
+	drm_fb_helper_fini(fb_helper);
+err_free:
+	kfree(fbdev_cma);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(drm_fb_cma_fbdev_init_with_funcs);
+
+/**
+ * drm_fb_cma_fbdev_init() - Allocate and initialize fbdev emulation
+ * @dev: DRM device
+ * @preferred_bpp: Preferred bits per pixel for the device.
+ *                 @dev->mode_config.preferred_depth is used if this is zero.
+ * @max_conn_count: Maximum number of connectors.
+ *                  @dev->mode_config.num_connector is used if this is zero.
+ *
+ * Returns:
+ * Zero on success or negative error code on failure.
+ */
+int drm_fb_cma_fbdev_init(struct drm_device *dev, unsigned int preferred_bpp,
+			  unsigned int max_conn_count)
+{
+	return drm_fb_cma_fbdev_init_with_funcs(dev, preferred_bpp,
+						max_conn_count, NULL);
+}
+EXPORT_SYMBOL_GPL(drm_fb_cma_fbdev_init);
+
+/**
+ * drm_fb_cma_fbdev_fini() - Teardown fbdev emulation
+ * @dev: DRM device
+ */
+void drm_fb_cma_fbdev_fini(struct drm_device *dev)
+{
+	struct drm_fb_helper *fb_helper = dev->fb_helper;
+
+	if (!fb_helper)
+		return;
+
+	/* Unregister if it hasn't been done already */
+	if (fb_helper->fbdev && fb_helper->fbdev->dev)
+		drm_fb_helper_unregister_fbi(fb_helper);
+
+	if (fb_helper->fbdev)
+		drm_fbdev_cma_defio_fini(fb_helper->fbdev);
+
+	if (fb_helper->fb)
+		drm_framebuffer_remove(fb_helper->fb);
+
+	drm_fb_helper_fini(fb_helper);
+	kfree(to_fbdev_cma(fb_helper));
+}
+EXPORT_SYMBOL_GPL(drm_fb_cma_fbdev_fini);
+
 /**
  * drm_fbdev_cma_init_with_funcs() - Allocate and initializes a drm_fbdev_cma struct
  * @dev: DRM device

include/drm/drm_fb_cma_helper.h

@@ -16,6 +16,13 @@ struct drm_mode_fb_cmd2;
 struct drm_plane;
 struct drm_plane_state;
 
+int drm_fb_cma_fbdev_init_with_funcs(struct drm_device *dev,
+	unsigned int preferred_bpp, unsigned int max_conn_count,
+	const struct drm_framebuffer_funcs *funcs);
+int drm_fb_cma_fbdev_init(struct drm_device *dev, unsigned int preferred_bpp,
+			  unsigned int max_conn_count);
+void drm_fb_cma_fbdev_fini(struct drm_device *dev);
+
 struct drm_fbdev_cma *drm_fbdev_cma_init_with_funcs(struct drm_device *dev,
 	unsigned int preferred_bpp, unsigned int max_conn_count,
 	const struct drm_framebuffer_funcs *funcs);