[Intel-gfx] [RFC 5/7] drm: Handle fbdev emulation in core

[Noralf Trønnes]

Prepare for generic fbdev emulation by letting DRM core work directly
with the fbdev compatibility layer. This is done by adding new fbdev
helper vtable callbacks for restore, hotplug_event, unregister and
release.

Signed-off-by: Noralf Trønnes <noralf at tronnes.org>
---
 drivers/gpu/drm/drm_file.c         | 12 +++++++++++-
 drivers/gpu/drm/drm_mode_config.c  | 10 ++++++++++
 drivers/gpu/drm/drm_probe_helper.c |  4 ++++
 include/drm/drm_fb_helper.h        | 33 +++++++++++++++++++++++++++++++++
 4 files changed, 58 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/drm_file.c b/drivers/gpu/drm/drm_file.c
index d208faade27e..67f0309e22ff 100644
--- a/drivers/gpu/drm/drm_file.c
+++ b/drivers/gpu/drm/drm_file.c
@@ -35,6 +35,7 @@
 #include <linux/slab.h>
 #include <linux/module.h>
 
+#include <drm/drm_fb_helper.h>
 #include <drm/drm_file.h>
 #include <drm/drmP.h>
 
@@ -439,10 +440,19 @@ static void drm_legacy_dev_reinit(struct drm_device *dev)
 
 void drm_lastclose(struct drm_device * dev)
 {
+	struct drm_fb_helper *fb_helper = dev->fb_helper;
+	int ret;
+
 	DRM_DEBUG("\n");
 
-	if (dev->driver->lastclose)
+	if (dev->driver->lastclose) {
 		dev->driver->lastclose(dev);
+	} else if (fb_helper && fb_helper->funcs && fb_helper->funcs->restore) {
+		ret = fb_helper->funcs->restore(fb_helper);
+		if (ret)
+			DRM_ERROR("Failed to restore fbdev: %d\n", ret);
+	}
+
 	DRM_DEBUG("driver lastclose completed\n");
 
 	if (drm_core_check_feature(dev, DRIVER_LEGACY))
diff --git a/drivers/gpu/drm/drm_mode_config.c b/drivers/gpu/drm/drm_mode_config.c
index bc5c46306b3d..260eb1730244 100644
--- a/drivers/gpu/drm/drm_mode_config.c
+++ b/drivers/gpu/drm/drm_mode_config.c
@@ -21,6 +21,7 @@
  */
 
 #include <drm/drm_encoder.h>
+#include <drm/drm_fb_helper.h>
 #include <drm/drm_mode_config.h>
 #include <drm/drmP.h>
 
@@ -61,6 +62,11 @@ int drm_modeset_register_all(struct drm_device *dev)
 
 void drm_modeset_unregister_all(struct drm_device *dev)
 {
+	struct drm_fb_helper *fb_helper = dev->fb_helper;
+
+	if (fb_helper && fb_helper->funcs && fb_helper->funcs->unregister)
+		fb_helper->funcs->unregister(fb_helper);
+
 	drm_connector_unregister_all(dev);
 	drm_encoder_unregister_all(dev);
 	drm_crtc_unregister_all(dev);
@@ -408,6 +414,7 @@ EXPORT_SYMBOL(drm_mode_config_init);
  */
 void drm_mode_config_cleanup(struct drm_device *dev)
 {
+	struct drm_fb_helper *fb_helper = dev->fb_helper;
 	struct drm_connector *connector;
 	struct drm_connector_list_iter conn_iter;
 	struct drm_crtc *crtc, *ct;
@@ -417,6 +424,9 @@ void drm_mode_config_cleanup(struct drm_device *dev)
 	struct drm_property_blob *blob, *bt;
 	struct drm_plane *plane, *plt;
 
+	if (fb_helper && fb_helper->funcs && fb_helper->funcs->release)
+		fb_helper->funcs->release(fb_helper);
+
 	list_for_each_entry_safe(encoder, enct, &dev->mode_config.encoder_list,
 				 head) {
 		encoder->funcs->destroy(encoder);
diff --git a/drivers/gpu/drm/drm_probe_helper.c b/drivers/gpu/drm/drm_probe_helper.c
index 555fbe54d6e2..9d8b0ba54173 100644
--- a/drivers/gpu/drm/drm_probe_helper.c
+++ b/drivers/gpu/drm/drm_probe_helper.c
@@ -559,10 +559,14 @@ EXPORT_SYMBOL(drm_helper_probe_single_connector_modes);
  */
 void drm_kms_helper_hotplug_event(struct drm_device *dev)
 {
+	struct drm_fb_helper *fb_helper = dev->fb_helper;
+
 	/* send a uevent + call fbdev */
 	drm_sysfs_hotplug_event(dev);
 	if (dev->mode_config.funcs->output_poll_changed)
 		dev->mode_config.funcs->output_poll_changed(dev);
+	else if (fb_helper && fb_helper->funcs && fb_helper->funcs->hotplug_event)
+		fb_helper->funcs->hotplug_event(fb_helper);
 }
 EXPORT_SYMBOL(drm_kms_helper_hotplug_event);
 
diff --git a/include/drm/drm_fb_helper.h b/include/drm/drm_fb_helper.h
index 5d4ccc3f28aa..f5ea79bbb831 100644
--- a/include/drm/drm_fb_helper.h
+++ b/include/drm/drm_fb_helper.h
@@ -125,6 +125,39 @@ struct drm_fb_helper_funcs {
 			       struct drm_display_mode **modes,
 			       struct drm_fb_offset *offsets,
 			       bool *enabled, int width, int height);
+
+	/**
+	 * @restore:
+	 *
+	 * Optional callback for restoring fbdev emulation.
+	 * Called by drm_lastclose() if &drm_driver->lastclose is not set.
+	 */
+	int (*restore)(struct drm_fb_helper *fb_helper);
+
+	/**
+	 * @hotplug_event:
+	 *
+	 * Optional callback for hotplug events.
+	 * Called by drm_kms_helper_hotplug_event() if
+	 * &drm_mode_config_funcs->output_poll_changed  is not set.
+	 */
+	int (*hotplug_event)(struct drm_fb_helper *fb_helper);
+
+	/**
+	 * @unregister:
+	 *
+	 * Optional callback for unregistrering fbdev emulation.
+	 * Called by drm_dev_unregister().
+	 */
+	void (*unregister)(struct drm_fb_helper *fb_helper);
+
+	/**
+	 * @release:
+	 *
+	 * Optional callback for releasing fbdev emulation resources.
+	 * Called by drm_mode_config_cleanup().
+	 */
+	void (*release)(struct drm_fb_helper *fb_helper);
 };
 
 struct drm_fb_helper_connector {
-- 
2.14.2