drm/exynos: make sure that hardware overlay for hdmi is disabled

the values set to registers will be updated into real registers
at vsync so dma operation could be malfunctioned when accessed
to memory after gem buffer was released. this patch makes sure
that hw overlay is disabled before the gem buffer is released.

Signed-off-by: Inki Dae <inki.dae@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>

drivers/gpu/drm/exynos/exynos_drm_hdmi.c

@@ -274,10 +274,21 @@ static void drm_mixer_disable(struct device *subdrv_dev, int zpos)
 	ctx->enabled[win] = false;
 }
 
+static void drm_mixer_wait_for_vblank(struct device *subdrv_dev)
+{
+	struct drm_hdmi_context *ctx = to_context(subdrv_dev);
+
+	DRM_DEBUG_KMS("%s\n", __FILE__);
+
+	if (mixer_ops && mixer_ops->wait_for_vblank)
+		mixer_ops->wait_for_vblank(ctx->mixer_ctx->ctx);
+}
+
 static struct exynos_drm_overlay_ops drm_hdmi_overlay_ops = {
 	.mode_set = drm_mixer_mode_set,
 	.commit = drm_mixer_commit,
 	.disable = drm_mixer_disable,
+	.wait_for_vblank = drm_mixer_wait_for_vblank,
 };
 
 static struct exynos_drm_manager hdmi_manager = {

drivers/gpu/drm/exynos/exynos_drm_hdmi.h

@@ -67,6 +67,7 @@ struct exynos_mixer_ops {
 	void (*dpms)(void *ctx, int mode);
 
 	/* overlay */
+	void (*wait_for_vblank)(void *ctx);
 	void (*win_mode_set)(void *ctx, struct exynos_drm_overlay *overlay);
 	void (*win_commit)(void *ctx, int zpos);
 	void (*win_disable)(void *ctx, int zpos);

drivers/gpu/drm/exynos/exynos_mixer.c

@@ -726,6 +726,18 @@ static void mixer_dpms(void *ctx, int mode)
 	}
 }
 
+static void mixer_wait_for_vblank(void *ctx)
+{
+	struct mixer_context *mixer_ctx = ctx;
+	struct mixer_resources *res = &mixer_ctx->mixer_res;
+	int ret;
+
+	ret = wait_for((mixer_reg_read(res, MXR_INT_STATUS) &
+				MXR_INT_STATUS_VSYNC), 50);
+	if (ret < 0)
+		DRM_DEBUG_KMS("vblank wait timed out.\n");
+}
+
 static void mixer_win_mode_set(void *ctx,
 			      struct exynos_drm_overlay *overlay)
 {
@@ -818,6 +830,7 @@ static struct exynos_mixer_ops mixer_ops = {
 	.dpms			= mixer_dpms,
 
 	/* overlay */
+	.wait_for_vblank	= mixer_wait_for_vblank,
 	.win_mode_set		= mixer_win_mode_set,
 	.win_commit		= mixer_win_commit,
 	.win_disable		= mixer_win_disable,