include: <linux/math64.h>: sync with upstream

The header implements definitions for the 64-bit division helpers
on 64-bit builds only. For 32-bit builds, it can only provide prototypes
and the actual implementation will need to come from elsewhere.

We didn't have any out-of-line definitions in barebox with the result
that functions like div_s64_rem() were so far only usable in
64-bit barebox builds. On 32-bit builds, they would result in a linker
error.

Import the Linux v5.11-rc1 generic out-of-line 64-bit math on 32-bit
implementation to fix this. While at it, synchronize the header to
reduce diff to upstream.

Signed-off-by: Ahmad Fatoum <ahmad@a3f.at>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

1 files changed, 206 insertions, 5 deletions

diff --git a/include/linux/math64.h b/include/linux/math64.h
index 71dd6d7109..e8b737e70e 100644
--- a/include/linux/math64.h
+++ b/include/linux/math64.h
@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: GPL-2.0 */
 #ifndef _LINUX_MATH64_H
 #define _LINUX_MATH64_H
 
@@ -6,10 +7,16 @@
 
 #if BITS_PER_LONG == 64
 
-#define div64_long(x,y) div64_s64((x),(y))
+#define div64_long(x, y) div64_s64((x), (y))
+#define div64_ul(x, y)   div64_u64((x), (y))
 
 /**
  * div_u64_rem - unsigned 64bit divide with 32bit divisor with remainder
+ * @dividend: unsigned 64bit dividend
+ * @divisor: unsigned 32bit divisor
+ * @remainder: pointer to unsigned 32bit remainder
+ *
+ * Return: sets ``*remainder``, then returns dividend / divisor
  *
  * This is commonly provided by 32bit archs to provide an optimized 64bit
  * divide.
@@ -20,8 +27,13 @@ static inline u64 div_u64_rem(u64 dividend, u32 divisor, u32 *remainder)
 	return dividend / divisor;
 }
 
-/**
+/*
  * div_s64_rem - signed 64bit divide with 32bit divisor with remainder
+ * @dividend: signed 64bit dividend
+ * @divisor: signed 32bit divisor
+ * @remainder: pointer to signed 32bit remainder
+ *
+ * Return: sets ``*remainder``, then returns dividend / divisor
  */
 static inline s64 div_s64_rem(s64 dividend, s32 divisor, s32 *remainder)
 {
@@ -29,16 +41,38 @@ static inline s64 div_s64_rem(s64 dividend, s32 divisor, s32 *remainder)
 	return dividend / divisor;
 }
 
-/**
+/*
+ * div64_u64_rem - unsigned 64bit divide with 64bit divisor and remainder
+ * @dividend: unsigned 64bit dividend
+ * @divisor: unsigned 64bit divisor
+ * @remainder: pointer to unsigned 64bit remainder
+ *
+ * Return: sets ``*remainder``, then returns dividend / divisor
+ */
+static inline u64 div64_u64_rem(u64 dividend, u64 divisor, u64 *remainder)
+{
+	*remainder = dividend % divisor;
+	return dividend / divisor;
+}
+
+/*
  * div64_u64 - unsigned 64bit divide with 64bit divisor
+ * @dividend: unsigned 64bit dividend
+ * @divisor: unsigned 64bit divisor
+ *
+ * Return: dividend / divisor
  */
 static inline u64 div64_u64(u64 dividend, u64 divisor)
 {
 	return dividend / divisor;
 }
 
-/**
+/*
  * div64_s64 - signed 64bit divide with 64bit divisor
+ * @dividend: signed 64bit dividend
+ * @divisor: signed 64bit divisor
+ *
+ * Return: dividend / divisor
  */
 static inline s64 div64_s64(s64 dividend, s64 divisor)
 {
@@ -47,7 +81,8 @@ static inline s64 div64_s64(s64 dividend, s64 divisor)
 
 #elif BITS_PER_LONG == 32
 
-#define div64_long(x,y) div_s64((x),(y))
+#define div64_long(x, y) div_s64((x), (y))
+#define div64_ul(x, y)   div_u64((x), (y))
 
 #ifndef div_u64_rem
 static inline u64 div_u64_rem(u64 dividend, u32 divisor, u32 *remainder)
@@ -61,6 +96,10 @@ static inline u64 div_u64_rem(u64 dividend, u32 divisor, u32 *remainder)
 extern s64 div_s64_rem(s64 dividend, s32 divisor, s32 *remainder);
 #endif
 
+#ifndef div64_u64_rem
+extern u64 div64_u64_rem(u64 dividend, u64 divisor, u64 *remainder);
+#endif
+
 #ifndef div64_u64
 extern u64 div64_u64(u64 dividend, u64 divisor);
 #endif
@@ -73,6 +112,8 @@ extern s64 div64_s64(s64 dividend, s64 divisor);
 
 /**
  * div_u64 - unsigned 64bit divide with 32bit divisor
+ * @dividend: unsigned 64bit dividend
+ * @divisor: unsigned 32bit divisor
  *
  * This is the most common 64bit divide and should be used if possible,
  * as many 32bit archs can optimize this variant better than a full 64bit
@@ -88,6 +129,8 @@ static inline u64 div_u64(u64 dividend, u32 divisor)
 
 /**
  * div_s64 - signed 64bit divide with 32bit divisor
+ * @dividend: signed 64bit dividend
+ * @divisor: signed 32bit divisor
  */
 #ifndef div_s64
 static inline s64 div_s64(s64 dividend, s32 divisor)
@@ -99,6 +142,164 @@ static inline s64 div_s64(s64 dividend, s32 divisor)
 
 u32 iter_div_u64_rem(u64 dividend, u32 divisor, u64 *remainder);
 
+#ifndef mul_u32_u32
+/*
+ * Many a GCC version messes this up and generates a 64x64 mult :-(
+ */
+static inline u64 mul_u32_u32(u32 a, u32 b)
+{
+	return (u64)a * b;
+}
+#endif
+
+#if defined(CONFIG_ARCH_SUPPORTS_INT128) && defined(__SIZEOF_INT128__)
+
+#ifndef mul_u64_u32_shr
+static inline u64 mul_u64_u32_shr(u64 a, u32 mul, unsigned int shift)
+{
+	return (u64)(((unsigned __int128)a * mul) >> shift);
+}
+#endif /* mul_u64_u32_shr */
+
+#ifndef mul_u64_u64_shr
+static inline u64 mul_u64_u64_shr(u64 a, u64 mul, unsigned int shift)
+{
+	return (u64)(((unsigned __int128)a * mul) >> shift);
+}
+#endif /* mul_u64_u64_shr */
+
+#else
+
+#ifndef mul_u64_u32_shr
+static inline u64 mul_u64_u32_shr(u64 a, u32 mul, unsigned int shift)
+{
+	u32 ah, al;
+	u64 ret;
+
+	al = a;
+	ah = a >> 32;
+
+	ret = mul_u32_u32(al, mul) >> shift;
+	if (ah)
+		ret += mul_u32_u32(ah, mul) << (32 - shift);
+
+	return ret;
+}
+#endif /* mul_u64_u32_shr */
+
+#ifndef mul_u64_u64_shr
+static inline u64 mul_u64_u64_shr(u64 a, u64 b, unsigned int shift)
+{
+	union {
+		u64 ll;
+		struct {
+#ifdef __BIG_ENDIAN
+			u32 high, low;
+#else
+			u32 low, high;
+#endif
+		} l;
+	} rl, rm, rn, rh, a0, b0;
+	u64 c;
+
+	a0.ll = a;
+	b0.ll = b;
+
+	rl.ll = mul_u32_u32(a0.l.low, b0.l.low);
+	rm.ll = mul_u32_u32(a0.l.low, b0.l.high);
+	rn.ll = mul_u32_u32(a0.l.high, b0.l.low);
+	rh.ll = mul_u32_u32(a0.l.high, b0.l.high);
+
+	/*
+	 * Each of these lines computes a 64-bit intermediate result into "c",
+	 * starting at bits 32-95.  The low 32-bits go into the result of the
+	 * multiplication, the high 32-bits are carried into the next step.
+	 */
+	rl.l.high = c = (u64)rl.l.high + rm.l.low + rn.l.low;
+	rh.l.low = c = (c >> 32) + rm.l.high + rn.l.high + rh.l.low;
+	rh.l.high = (c >> 32) + rh.l.high;
+
+	/*
+	 * The 128-bit result of the multiplication is in rl.ll and rh.ll,
+	 * shift it right and throw away the high part of the result.
+	 */
+	if (shift == 0)
+		return rl.ll;
+	if (shift < 64)
+		return (rl.ll >> shift) | (rh.ll << (64 - shift));
+	return rh.ll >> (shift & 63);
+}
+#endif /* mul_u64_u64_shr */
+
+#endif
+
+#ifndef mul_u64_u32_div
+static inline u64 mul_u64_u32_div(u64 a, u32 mul, u32 divisor)
+{
+	union {
+		u64 ll;
+		struct {
+#ifdef __BIG_ENDIAN
+			u32 high, low;
+#else
+			u32 low, high;
+#endif
+		} l;
+	} u, rl, rh;
+
+	u.ll = a;
+	rl.ll = mul_u32_u32(u.l.low, mul);
+	rh.ll = mul_u32_u32(u.l.high, mul) + rl.l.high;
+
+	/* Bits 32-63 of the result will be in rh.l.low. */
+	rl.l.high = do_div(rh.ll, divisor);
+
+	/* Bits 0-31 of the result will be in rl.l.low.	*/
+	do_div(rl.ll, divisor);
+
+	rl.l.high = rh.l.low;
+	return rl.ll;
+}
+#endif /* mul_u64_u32_div */
+
+u64 mul_u64_u64_div_u64(u64 a, u64 mul, u64 div);
+
+#define DIV64_U64_ROUND_UP(ll, d)	\
+	({ u64 _tmp = (d); div64_u64((ll) + _tmp - 1, _tmp); })
+
+/**
+ * DIV64_U64_ROUND_CLOSEST - unsigned 64bit divide with 64bit divisor rounded to nearest integer
+ * @dividend: unsigned 64bit dividend
+ * @divisor: unsigned 64bit divisor
+ *
+ * Divide unsigned 64bit dividend by unsigned 64bit divisor
+ * and round to closest integer.
+ *
+ * Return: dividend / divisor rounded to nearest integer
+ */
+#define DIV64_U64_ROUND_CLOSEST(dividend, divisor)	\
+	({ u64 _tmp = (divisor); div64_u64((dividend) + _tmp / 2, _tmp); })
+
+/*
+ * DIV_S64_ROUND_CLOSEST - signed 64bit divide with 32bit divisor rounded to nearest integer
+ * @dividend: signed 64bit dividend
+ * @divisor: signed 32bit divisor
+ *
+ * Divide signed 64bit dividend by signed 32bit divisor
+ * and round to closest integer.
+ *
+ * Return: dividend / divisor rounded to nearest integer
+ */
+#define DIV_S64_ROUND_CLOSEST(dividend, divisor)(	\
+{							\
+	s64 __x = (dividend);				\
+	s32 __d = (divisor);				\
+	((__x > 0) == (__d > 0)) ?			\
+		div_s64((__x + (__d / 2)), __d) :	\
+		div_s64((__x - (__d / 2)), __d);	\
+}							\
+)
+
 static __always_inline u32
 __iter_div_u64_rem(u64 dividend, u32 divisor, u64 *remainder)
 {