--- zzzz-none-000/linux-3.10.107/include/drm/drm_fixed.h	2017-06-27 09:49:32.000000000 +0000
+++ scorpion-7490-727/linux-3.10.107/include/drm/drm_fixed.h	2021-02-04 17:41:59.000000000 +0000
@@ -20,10 +20,13 @@
  * OTHER DEALINGS IN THE SOFTWARE.
  *
  * Authors: Dave Airlie
+ *          Christian König
  */
 #ifndef DRM_FIXED_H
 #define DRM_FIXED_H
 
+#include <linux/math64.h>
+
 typedef union dfixed {
 	u32 full;
 } fixed20_12;
@@ -65,4 +68,144 @@
 	tmp /= 2;
 	return lower_32_bits(tmp);
 }
+
+#define DRM_FIXED_POINT		32
+#define DRM_FIXED_ONE		(1ULL << DRM_FIXED_POINT)
+#define DRM_FIXED_DECIMAL_MASK	(DRM_FIXED_ONE - 1)
+#define DRM_FIXED_DIGITS_MASK	(~DRM_FIXED_DECIMAL_MASK)
+#define DRM_FIXED_EPSILON	1LL
+#define DRM_FIXED_ALMOST_ONE	(DRM_FIXED_ONE - DRM_FIXED_EPSILON)
+
+static inline s64 drm_int2fixp(int a)
+{
+	return ((s64)a) << DRM_FIXED_POINT;
+}
+
+static inline int drm_fixp2int(s64 a)
+{
+	return ((s64)a) >> DRM_FIXED_POINT;
+}
+
+static inline int drm_fixp2int_ceil(s64 a)
+{
+	if (a > 0)
+		return drm_fixp2int(a + DRM_FIXED_ALMOST_ONE);
+	else
+		return drm_fixp2int(a - DRM_FIXED_ALMOST_ONE);
+}
+
+static inline unsigned drm_fixp_msbset(s64 a)
+{
+	unsigned shift, sign = (a >> 63) & 1;
+
+	for (shift = 62; shift > 0; --shift)
+		if (((a >> shift) & 1) != sign)
+			return shift;
+
+	return 0;
+}
+
+static inline s64 drm_fixp_mul(s64 a, s64 b)
+{
+	unsigned shift = drm_fixp_msbset(a) + drm_fixp_msbset(b);
+	s64 result;
+
+	if (shift > 61) {
+		shift = shift - 61;
+		a >>= (shift >> 1) + (shift & 1);
+		b >>= shift >> 1;
+	} else
+		shift = 0;
+
+	result = a * b;
+
+	if (shift > DRM_FIXED_POINT)
+		return result << (shift - DRM_FIXED_POINT);
+
+	if (shift < DRM_FIXED_POINT)
+		return result >> (DRM_FIXED_POINT - shift);
+
+	return result;
+}
+
+static inline s64 drm_fixp_div(s64 a, s64 b)
+{
+	unsigned shift = 62 - drm_fixp_msbset(a);
+	s64 result;
+
+	a <<= shift;
+
+	if (shift < DRM_FIXED_POINT)
+		b >>= (DRM_FIXED_POINT - shift);
+
+	result = div64_s64(a, b);
+
+	if (shift > DRM_FIXED_POINT)
+		return result >> (shift - DRM_FIXED_POINT);
+
+	return result;
+}
+
+static inline s64 drm_fixp_from_fraction(s64 a, s64 b)
+{
+	s64 res;
+	bool a_neg = a < 0;
+	bool b_neg = b < 0;
+	u64 a_abs = a_neg ? -a : a;
+	u64 b_abs = b_neg ? -b : b;
+	u64 rem;
+
+	/* determine integer part */
+	u64 res_abs  = div64_u64_rem(a_abs, b_abs, &rem);
+
+	/* determine fractional part */
+	{
+		u32 i = DRM_FIXED_POINT;
+
+		do {
+			rem <<= 1;
+			res_abs <<= 1;
+			if (rem >= b_abs) {
+				res_abs |= 1;
+				rem -= b_abs;
+			}
+		} while (--i != 0);
+	}
+
+	/* round up LSB */
+	{
+		u64 summand = (rem << 1) >= b_abs;
+
+		res_abs += summand;
+	}
+
+	res = (s64) res_abs;
+	if (a_neg ^ b_neg)
+		res = -res;
+	return res;
+}
+
+static inline s64 drm_fixp_exp(s64 x)
+{
+	s64 tolerance = div64_s64(DRM_FIXED_ONE, 1000000);
+	s64 sum = DRM_FIXED_ONE, term, y = x;
+	u64 count = 1;
+
+	if (x < 0)
+		y = -1 * x;
+
+	term = y;
+
+	while (term >= tolerance) {
+		sum = sum + term;
+		count = count + 1;
+		term = drm_fixp_mul(term, div64_s64(y, count));
+	}
+
+	if (x < 0)
+		sum = drm_fixp_div(DRM_FIXED_ONE, sum);
+
+	return sum;
+}
+
 #endif