From e26d5afdae4e6c6b0d66af77e0ee050ecb06a7cb Mon Sep 17 00:00:00 2001
From: Lloyd Atkinson <latkinso@codeaurora.org>
Date: Tue, 17 Jan 2017 12:08:48 -0500
Subject: drm/msm/sde: add rectangle utility functions to sde

Add rectangle intersection and other utility functions to the
sde kms utilities.

Change-Id: I10a1f60480df10a93541990b3efa347264c6432f
Signed-off-by: Lloyd Atkinson <latkinso@codeaurora.org>
Signed-off-by: Abhinav Kumar <abhinavk@codeaurora.org>
---
 drivers/gpu/drm/msm/sde/sde_kms.h       | 43 +++++++++++++++++++++++++++++++++
 drivers/gpu/drm/msm/sde/sde_kms_utils.c | 26 +++++++++++++++++++-
 2 files changed, 68 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/msm/sde/sde_kms.h b/drivers/gpu/drm/msm/sde/sde_kms.h
index 2d36360c67b5..88ec4753a8a7 100644
--- a/drivers/gpu/drm/msm/sde/sde_kms.h
+++ b/drivers/gpu/drm/msm/sde/sde_kms.h
@@ -368,6 +368,49 @@ void sde_kms_info_append_format(struct sde_kms_info *info,
  */
 void sde_kms_info_stop(struct sde_kms_info *info);
 
+/**
+ * sde_kms_rect_intersect - intersect two rectangles
+ * @r1: first rectangle
+ * @r2: scissor rectangle
+ * @result: result rectangle, all 0's on no intersection found
+ */
+void sde_kms_rect_intersect(const struct sde_rect *r1,
+		const struct sde_rect *r2,
+		struct sde_rect *result);
+
+/**
+ * sde_kms_rect_is_equal - compares two rects
+ * @r1: rect value to compare
+ * @r2: rect value to compare
+ *
+ * Returns 1 if the rects are same, 0 otherwise.
+ */
+static inline bool sde_kms_rect_is_equal(struct sde_rect *r1,
+		struct sde_rect *r2)
+{
+	if ((!r1 && r2) || (r1 && !r2))
+		return false;
+
+	if (!r1 && !r2)
+		return true;
+
+	return r1->x == r2->x && r1->y == r2->y && r1->w == r2->w &&
+			r1->h == r2->h;
+}
+
+/**
+ * sde_kms_rect_is_null - returns true if the width or height of a rect is 0
+ * @rect: rectangle to check for zero size
+ * @Return: True if width or height of rectangle is 0
+ */
+static inline bool sde_kms_rect_is_null(const struct sde_rect *r)
+{
+	if (!r)
+		return true;
+
+	return (!r->w || !r->h);
+}
+
 /**
  * Vblank enable/disable functions
  */
diff --git a/drivers/gpu/drm/msm/sde/sde_kms_utils.c b/drivers/gpu/drm/msm/sde/sde_kms_utils.c
index 6e29c09deb40..30e12c969538 100644
--- a/drivers/gpu/drm/msm/sde/sde_kms_utils.c
+++ b/drivers/gpu/drm/msm/sde/sde_kms_utils.c
@@ -1,4 +1,4 @@
-/* Copyright (c) 2015-2016, The Linux Foundation. All rights reserved.
+/* Copyright (c) 2015-2017, The Linux Foundation. All rights reserved.
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 2 and
@@ -151,3 +151,27 @@ void sde_kms_info_stop(struct sde_kms_info *info)
 			info->len = info->staged_len + len;
 	}
 }
+
+void sde_kms_rect_intersect(const struct sde_rect *r1,
+		const struct sde_rect *r2,
+		struct sde_rect *result)
+{
+	int l, t, r, b;
+
+	if (!r1 || !r2 || !result)
+		return;
+
+	l = max(r1->x, r2->x);
+	t = max(r1->y, r2->y);
+	r = min((r1->x + r1->w), (r2->x + r2->w));
+	b = min((r1->y + r1->h), (r2->y + r2->h));
+
+	if (r < l || b < t) {
+		memset(result, 0, sizeof(*result));
+	} else {
+		result->x = l;
+		result->y = t;
+		result->w = r - l;
+		result->h = b - t;
+	}
+}
-- 
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