drm/client: Add client free callback to unprepare fb_helper

Add free callback to struct drm_client_funcs. Invoke function to
free the client memory as part of the release process. Implement
free for fbdev emulation.

Fbdev emulation allocates and prepares client memory in
drm_fbdev_client_setup(). The release happens in fb_destroy from
struct fb_ops. Multiple implementations of this callback exist in
the various drivers that provide an fbdev implementation. Each of
them needs to follow the implementation details of the fbdev setup
code.

Adding a free callback for the client puts the unprepare and release
of the fbdev client in a single place.

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com> # core, msm
Acked-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com> # omapdrm
Acked-by: Patrik Jakobsson <patrik.r.jakobsson@gmail.com> # gma500
Acked-by: Alex Deucher <alexander.deucher@amd.com>
Link: https://lore.kernel.org/r/20251009132006.45834-2-tzimmermann@suse.de

Author: tdz

drivers/gpu/drm/armada/armada_fbdev.c

@@ -28,8 +28,6 @@ static void armada_fbdev_fb_destroy(struct fb_info *info)
 	fbh->fb->funcs->destroy(fbh->fb);
 
 	drm_client_release(&fbh->client);
-	drm_fb_helper_unprepare(fbh);
-	kfree(fbh);
 }
 
 static const struct fb_ops armada_fb_ops = {

drivers/gpu/drm/clients/drm_fbdev_client.c

@@ -13,16 +13,28 @@
  * struct drm_client_funcs
  */
 
+static void drm_fbdev_client_free(struct drm_client_dev *client)
+{
+	struct drm_fb_helper *fb_helper = drm_fb_helper_from_client(client);
+
+	drm_fb_helper_unprepare(fb_helper);
+	kfree(fb_helper);
+}
+
 static void drm_fbdev_client_unregister(struct drm_client_dev *client)
 {
 	struct drm_fb_helper *fb_helper = drm_fb_helper_from_client(client);
 
 	if (fb_helper->info) {
+		/*
+		 * Fully probed framebuffer device
+		 */
 		drm_fb_helper_unregister_info(fb_helper);
 	} else {
+		/*
+		 * Partially initialized client, no framebuffer device yet
+		 */
 		drm_client_release(&fb_helper->client);
-		drm_fb_helper_unprepare(fb_helper);
-		kfree(fb_helper);
 	}
 }
 
@@ -82,6 +94,7 @@ static int drm_fbdev_client_resume(struct drm_client_dev *client)
 
 static const struct drm_client_funcs drm_fbdev_client_funcs = {
 	.owner		= THIS_MODULE,
+	.free		= drm_fbdev_client_free,
 	.unregister	= drm_fbdev_client_unregister,
 	.restore	= drm_fbdev_client_restore,
 	.hotplug	= drm_fbdev_client_hotplug,

drivers/gpu/drm/drm_client.c

@@ -168,6 +168,10 @@ void drm_client_release(struct drm_client_dev *client)
 
 	drm_client_modeset_free(client);
 	drm_client_close(client);
+
+	if (client->funcs && client->funcs->free)
+		client->funcs->free(client);
+
 	drm_dev_put(dev);
 }
 EXPORT_SYMBOL(drm_client_release);

drivers/gpu/drm/drm_fbdev_dma.c

@@ -57,8 +57,6 @@ static void drm_fbdev_dma_fb_destroy(struct fb_info *info)
 	drm_client_buffer_vunmap(fb_helper->buffer);
 	drm_client_framebuffer_delete(fb_helper->buffer);
 	drm_client_release(&fb_helper->client);
-	drm_fb_helper_unprepare(fb_helper);
-	kfree(fb_helper);
 }
 
 static const struct fb_ops drm_fbdev_dma_fb_ops = {
@@ -92,8 +90,6 @@ static void drm_fbdev_dma_shadowed_fb_destroy(struct fb_info *info)
 	drm_client_buffer_vunmap(fb_helper->buffer);
 	drm_client_framebuffer_delete(fb_helper->buffer);
 	drm_client_release(&fb_helper->client);
-	drm_fb_helper_unprepare(fb_helper);
-	kfree(fb_helper);
 }
 
 static const struct fb_ops drm_fbdev_dma_shadowed_fb_ops = {

drivers/gpu/drm/drm_fbdev_shmem.c

@@ -65,8 +65,6 @@ static void drm_fbdev_shmem_fb_destroy(struct fb_info *info)
 	drm_client_buffer_vunmap(fb_helper->buffer);
 	drm_client_framebuffer_delete(fb_helper->buffer);
 	drm_client_release(&fb_helper->client);
-	drm_fb_helper_unprepare(fb_helper);
-	kfree(fb_helper);
 }
 
 static const struct fb_ops drm_fbdev_shmem_fb_ops = {

drivers/gpu/drm/drm_fbdev_ttm.c

@@ -53,8 +53,6 @@ static void drm_fbdev_ttm_fb_destroy(struct fb_info *info)
 	drm_client_framebuffer_delete(fb_helper->buffer);
 
 	drm_client_release(&fb_helper->client);
-	drm_fb_helper_unprepare(fb_helper);
-	kfree(fb_helper);
 }
 
 static const struct fb_ops drm_fbdev_ttm_fb_ops = {

drivers/gpu/drm/exynos/exynos_drm_fbdev.c

@@ -42,8 +42,6 @@ static void exynos_drm_fb_destroy(struct fb_info *info)
 	drm_framebuffer_remove(fb);
 
 	drm_client_release(&fb_helper->client);
-	drm_fb_helper_unprepare(fb_helper);
-	kfree(fb_helper);
 }
 
 static const struct fb_ops exynos_drm_fb_ops = {

drivers/gpu/drm/gma500/fbdev.c

@@ -84,9 +84,6 @@ static void psb_fbdev_fb_destroy(struct fb_info *info)
 	drm_gem_object_put(obj);
 
 	drm_client_release(&fb_helper->client);
-
-	drm_fb_helper_unprepare(fb_helper);
-	kfree(fb_helper);
 }
 
 static const struct fb_ops psb_fbdev_fb_ops = {

drivers/gpu/drm/i915/display/intel_fbdev.c

@@ -146,8 +146,6 @@ static void intel_fbdev_fb_destroy(struct fb_info *info)
 	drm_framebuffer_remove(fb_helper->fb);
 
 	drm_client_release(&fb_helper->client);
-	drm_fb_helper_unprepare(fb_helper);
-	kfree(fb_helper);
 }
 
 __diag_push();

drivers/gpu/drm/msm/msm_fbdev.c

@@ -52,8 +52,6 @@ static void msm_fbdev_fb_destroy(struct fb_info *info)
 	drm_framebuffer_remove(fb);
 
 	drm_client_release(&helper->client);
-	drm_fb_helper_unprepare(helper);
-	kfree(helper);
 }
 
 static const struct fb_ops msm_fb_ops = {