[RFC 2/3] drm/vkms: map/unmap buffers in [prepare/cleanup]_fb hooks

[Haneen Mohammed]

This patch checks plane state and use prepare/cleanup_fb
to map/unmap GEM backing memory to kernel address space.

Signed-off-by: Haneen Mohammed <hamohammed.sa at gmail.com>
---
 drivers/gpu/drm/vkms/vkms_drv.h   |  1 +
 drivers/gpu/drm/vkms/vkms_plane.c | 50 +++++++++++++++++++++++++++++++
 2 files changed, 51 insertions(+)

diff --git a/drivers/gpu/drm/vkms/vkms_drv.h b/drivers/gpu/drm/vkms/vkms_drv.h
index d6cb8824cee2..300e6a05d473 100644
--- a/drivers/gpu/drm/vkms/vkms_drv.h
+++ b/drivers/gpu/drm/vkms/vkms_drv.h
@@ -42,6 +42,7 @@ struct vkms_gem_object {
 	struct mutex pages_lock; /* Page lock used in page fault handler */
 	struct page **pages;
 	void *vaddr;
+	struct drm_plane_state *plane_state;
 };
 
 #define drm_crtc_to_vkms_output(target) \
diff --git a/drivers/gpu/drm/vkms/vkms_plane.c b/drivers/gpu/drm/vkms/vkms_plane.c
index f7f63143f6d0..c717f2a41c1d 100644
--- a/drivers/gpu/drm/vkms/vkms_plane.c
+++ b/drivers/gpu/drm/vkms/vkms_plane.c
@@ -9,6 +9,7 @@
 #include "vkms_drv.h"
 #include <drm/drm_plane_helper.h>
 #include <drm/drm_atomic_helper.h>
+#include <drm/drm_gem_framebuffer_helper.h>
 
 static const struct drm_plane_funcs vkms_plane_funcs = {
 	.update_plane		= drm_atomic_helper_update_plane,
@@ -22,6 +23,14 @@ static const struct drm_plane_funcs vkms_plane_funcs = {
 static int vkms_plane_atomic_check(struct drm_plane *plane,
 				   struct drm_plane_state *state)
 {
+	if (!state->crtc)
+		return 0;
+
+	drm_atomic_helper_check_plane_state(state, state->crtc->state,
+					    DRM_PLANE_HELPER_NO_SCALING,
+					    DRM_PLANE_HELPER_NO_SCALING,
+					    false, // false for primary planes
+					    true);
 	return 0;
 }
 
@@ -30,9 +39,50 @@ static void vkms_primary_plane_update(struct drm_plane *plane,
 {
 }
 
+static int vkms_prepare_fb(struct drm_plane *plane,
+			   struct drm_plane_state *state)
+{
+	struct drm_gem_object *gem_obj;
+	struct vkms_gem_object *vkms_obj;
+
+	if (!state->fb)
+		return 0;
+
+	gem_obj = drm_gem_fb_get_obj(state->fb, 0);
+	vkms_obj = container_of(gem_obj, struct vkms_gem_object, gem);
+	vkms_obj->plane_state = state;
+	vkms_obj->vaddr = vkms_gem_vmap(gem_obj);
+
+	if (!vkms_obj->vaddr)
+		DRM_INFO("vmap failed\n");
+
+	return drm_gem_fb_prepare_fb(plane, state);
+}
+
+static void vkms_cleanup_fb(struct drm_plane *plane,
+			    struct drm_plane_state *state)
+{
+	struct drm_gem_object *gem_obj;
+	struct vkms_gem_object *vkms_obj;
+
+	if (!state->fb)
+		return;
+
+	gem_obj = drm_gem_fb_get_obj(state->fb, 0);
+	vkms_obj = container_of(gem_obj, struct vkms_gem_object, gem);
+
+	if (vkms_obj && vkms_obj->pages) {
+		vunmap(vkms_obj->vaddr);
+		drm_gem_put_pages(gem_obj, vkms_obj->pages, false, true);
+		vkms_obj->pages = NULL;
+	}
+}
+
 static const struct drm_plane_helper_funcs vkms_primary_helper_funcs = {
 	.atomic_check		= vkms_plane_atomic_check,
 	.atomic_update		= vkms_primary_plane_update,
+	.prepare_fb		= vkms_prepare_fb,
+	.cleanup_fb		= vkms_cleanup_fb,
 };
 
 struct drm_plane *vkms_plane_init(struct vkms_device *vkmsdev)
-- 
2.17.1