drm/fb-helper: Remove drm_fb_helper_crtc

struct drm_fb_helper_crtc is now just a wrapper around drm_mode_set so
use that directly instead and attach it as a modeset array onto
drm_client_dev. drm_fb_helper will use this array to store its modesets
which means it will always initialize a drm_client, but it will not
register the client (callbacks) unless it's the generic fbdev emulation.

Code will later be moved to drm_client, so add code there in a new file
drm_client_modeset.c with MIT license to match drm_fb_helper.c.

The modeset connector array size is hardcoded for the cloned case to avoid
having to pass in a value from the driver. A value of 8 is chosen to err
on the safe side. This means that the max connector argument for
drm_fb_helper_init() and drm_fb_helper_fbdev_setup() isn't used anymore,
a todo entry for this is added.

In pan_display_atomic() restore_fbdev_mode_force() is used instead of
restore_fbdev_mode_atomic() because that one will later become internal
to drm_client_modeset.

Locking order:
1. drm_fb_helper->lock
2. drm_master_internal_acquire
3. drm_client_dev->modeset_mutex

v6: Improve commit message (Sam Ravnborg)

v3:
- Use full drm_client_init/release for the modesets (Daniel Vetter)
- drm_client_for_each_modeset: use lockdep_assert_held (Daniel Vetter)
- Hook up to Documentation/gpu/drm-client.rst (Daniel Vetter)

v2:
- Add modesets array to drm_client (Daniel Vetter)
- Use a new file for the modeset code (Daniel Vetter)
- File has to be MIT licensed (Emmanuel Vadot)
- Add copyrights from drm_fb_helper.c

Signed-off-by: Noralf Trønnes <noralf@tronnes.org>
Reviewed-by: Sam Ravnborg <sam@ravnborg.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20190531140117.37751-3-noralf@tronnes.org

2 files changed, 30 insertions, 8 deletions

diff --git a/include/drm/drm_client.h b/include/drm/drm_client.h
index 268b2cf0052a..87be9aeb1fe0 100644
--- a/include/drm/drm_client.h
+++ b/include/drm/drm_client.h
@@ -3,8 +3,12 @@
 #ifndef _DRM_CLIENT_H_
 #define _DRM_CLIENT_H_
 
+#include <linux/lockdep.h>
+#include <linux/mutex.h>
 #include <linux/types.h>
 
+#include <drm/drm_crtc.h>
+
 struct drm_client_dev;
 struct drm_device;
 struct drm_file;
@@ -13,6 +17,8 @@ struct drm_gem_object;
 struct drm_minor;
 struct module;
 
+#define DRM_CLIENT_MAX_CLONED_CONNECTORS	8
+
 /**
  * struct drm_client_funcs - DRM client callbacks
  */
@@ -85,6 +91,16 @@ struct drm_client_dev {
 	 * @file: DRM file
 	 */
 	struct drm_file *file;
+
+	/**
+	 * @modeset_mutex: Protects @modesets.
+	 */
+	struct mutex modeset_mutex;
+
+	/**
+	 * @modesets: CRTC configurations
+	 */
+	struct drm_mode_set *modesets;
 };
 
 int drm_client_init(struct drm_device *dev, struct drm_client_dev *client,
@@ -135,6 +151,20 @@ struct drm_client_buffer *
 drm_client_framebuffer_create(struct drm_client_dev *client, u32 width, u32 height, u32 format);
 void drm_client_framebuffer_delete(struct drm_client_buffer *buffer);
 
+int drm_client_modeset_create(struct drm_client_dev *client);
+void drm_client_modeset_free(struct drm_client_dev *client);
+void drm_client_modeset_release(struct drm_client_dev *client);
+struct drm_mode_set *drm_client_find_modeset(struct drm_client_dev *client, struct drm_crtc *crtc);
+
+/**
+ * drm_client_for_each_modeset() - Iterate over client modesets
+ * @modeset: &drm_mode_set loop cursor
+ * @client: DRM client
+ */
+#define drm_client_for_each_modeset(modeset, client) \
+	for (({ lockdep_assert_held(&(client)->modeset_mutex); }), \
+	     modeset = (client)->modesets; modeset->crtc; modeset++)
+
 int drm_client_debugfs_init(struct drm_minor *minor);
 
 #endif
diff --git a/include/drm/drm_fb_helper.h b/include/drm/drm_fb_helper.h
index 2af1c6d3e147..6b334f4d8a22 100644
--- a/include/drm/drm_fb_helper.h
+++ b/include/drm/drm_fb_helper.h
@@ -47,10 +47,6 @@ struct drm_fb_offset {
 	int x, y;
 };
 
-struct drm_fb_helper_crtc {
-	struct drm_mode_set mode_set;
-};
-
 /**
  * struct drm_fb_helper_surface_size - describes fbdev size and scanout surface size
  * @fb_width: fbdev width
@@ -109,8 +105,6 @@ struct drm_fb_helper_connector {
  * struct drm_fb_helper - main structure to emulate fbdev on top of KMS
  * @fb: Scanout framebuffer object
  * @dev: DRM device
- * @crtc_count: number of possible CRTCs
- * @crtc_info: per-CRTC helper state (mode, x/y offset, etc)
  * @connector_count: number of connected connectors
  * @connector_info_alloc_count: size of connector_info
  * @funcs: driver callbacks for fb helper
@@ -144,8 +138,6 @@ struct drm_fb_helper {
 
 	struct drm_framebuffer *fb;
 	struct drm_device *dev;
-	int crtc_count;
-	struct drm_fb_helper_crtc *crtc_info;
 	int connector_count;
 	int connector_info_alloc_count;
 	/**