msm: mdp3: implement overlay prepare ioctl for mdp3 driver

Implement overlay prepare ioctl call for mdp3 display driver. This will
allow a full frame with multiple overlays to be configured at once and
perform frame level checks before being pushed to display. This function
guarantees that if the call is successful, the frame can be displayed
successfully on the screen when display commit is called.

Change-Id: I761f48f81512fbe538565c4622d9299857350da1
Signed-off-by: Adrian Salido-Moreno <adrianm@codeaurora.org>
Signed-off-by: Mayank Chopra <makchopra@codeaurora.org>
diff --git a/drivers/video/msm/mdss/mdp3_ctrl.c b/drivers/video/msm/mdss/mdp3_ctrl.c
index eff1e81..27f67f4 100644
--- a/drivers/video/msm/mdss/mdp3_ctrl.c
+++ b/drivers/video/msm/mdss/mdp3_ctrl.c
@@ -1608,6 +1608,43 @@
 	return rc;
 }
 
+static int mdp3_overlay_prepare(struct msm_fb_data_type *mfd,
+		struct mdp_overlay_list __user *user_ovlist)
+{
+	struct mdp_overlay_list ovlist;
+	struct mdp3_session_data *mdp3_session = mfd->mdp.private1;
+	struct mdp_overlay *req;
+	int rc;
+
+	if (!mdp3_session)
+		return -ENODEV;
+
+	req = &mdp3_session->req_overlay;
+
+	if (copy_from_user(&ovlist, user_ovlist, sizeof(ovlist)))
+		return -EFAULT;
+
+	if (ovlist.num_overlays != 1) {
+		pr_err("OV_PREPARE failed: only 1 overlay allowed\n");
+		return -EINVAL;
+	}
+
+	if (copy_from_user(req, ovlist.overlay_list[0], sizeof(*req)))
+		return -EFAULT;
+
+	rc = mdp3_overlay_set(mfd, req);
+	if (!IS_ERR_VALUE(rc)) {
+		if (copy_to_user(ovlist.overlay_list[0], req, sizeof(*req)))
+			return -EFAULT;
+	}
+
+	if (put_user(IS_ERR_VALUE(rc) ? 0 : 1,
+			&user_ovlist->processed_overlays))
+		return -EFAULT;
+
+	return rc;
+}
+
 static int mdp3_ctrl_ioctl_handler(struct msm_fb_data_type *mfd,
 					u32 cmd, void __user *argp)
 {
@@ -1707,6 +1744,9 @@
 		if (rc)
 			pr_err("OVERLAY_PLAY failed (%d)\n", rc);
 		break;
+	case MSMFB_OVERLAY_PREPARE:
+		rc = mdp3_overlay_prepare(mfd, argp);
+		break;
 	default:
 		break;
 	}