The <linux/math.h> header has evolved upstream since we last imported
it. Sync it with Linux to make available some more functions for use in
barebox.
Signed-off-by: Ahmad Fatoum <a.fatoum@xxxxxxxxxxxxxx>
---
include/linux/math.h | 173 ++++++++++++++++++++++++++++++++++++-------
lib/math/Makefile | 1 +
lib/math/int_pow.c | 32 ++++++++
lib/math/int_sqrt.c | 44 ++++++++---
4 files changed, 212 insertions(+), 38 deletions(-)
create mode 100644 lib/math/int_pow.c
diff --git a/include/linux/math.h b/include/linux/math.h
index 48417aca7635..e7c47fa404ab 100644
--- a/include/linux/math.h
+++ b/include/linux/math.h
@@ -10,12 +10,27 @@
* get the type for the ~ right in round_down (it needs to be
* as wide as the result!), and we want to evaluate the macro
* arguments just once each.
- *
- * NOTE these functions only round to power-of-2 arguments. Use
- * roundup/rounddown for non power-of-2-arguments.
*/
#define __round_mask(x, y) ((__typeof__(x))((y)-1))
+
+/**
+ * round_up - round up to next specified power of 2
+ * @x: the value to round
+ * @y: multiple to round up to (must be a power of 2)
+ *
+ * Rounds @x up to next multiple of @y (which must be a power of 2).
+ * To perform arbitrary rounding up, use roundup() below.
+ */
#define round_up(x, y) ((((x)-1) | __round_mask(x, y))+1)
+
+/**
+ * round_down - round down to next specified power of 2
+ * @x: the value to round
+ * @y: multiple to round down to (must be a power of 2)
+ *
+ * Rounds @x down to next multiple of @y (which must be a power of 2).
+ * To perform arbitrary rounding down, use rounddown() below.
+ */
#define round_down(x, y) ((x) & ~__round_mask(x, y))
#define DIV_ROUND_UP(n,d) (((n) + (d) - 1) / (d))
@@ -26,10 +41,56 @@
#define DIV_ROUND_UP_ULL(ll, d) \
DIV_ROUND_DOWN_ULL((unsigned long long)(ll) + (d) - 1, (d))
+#if BITS_PER_LONG == 32
+# define DIV_ROUND_UP_SECTOR_T(ll,d) DIV_ROUND_UP_ULL(ll, d)
+#else
+# define DIV_ROUND_UP_SECTOR_T(ll,d) DIV_ROUND_UP(ll,d)
+#endif
+
+/**
+ * roundup - round up to the next specified multiple
+ * @x: the value to up
+ * @y: multiple to round up to
+ *
+ * Rounds @x up to next multiple of @y. If @y will always be a power
+ * of 2, consider using the faster round_up().
+ */
+#define roundup(x, y) ( \
+{ \
+ typeof(y) __y = y; \
+ (((x) + (__y - 1)) / __y) * __y; \
+} \
+)
+/**
+ * rounddown - round down to next specified multiple
+ * @x: the value to round
+ * @y: multiple to round down to
+ *
+ * Rounds @x down to next multiple of @y. If @y will always be a power
+ * of 2, consider using the faster round_down().
+ */
+#define rounddown(x, y) ( \
+{ \
+ typeof(x) __x = (x); \
+ __x - (__x % (y)); \
+} \
+)
+
+/*
+ * Divide positive or negative dividend by positive or negative divisor
+ * and round to closest integer. Result is undefined for negative
+ * divisors if the dividend variable type is unsigned and for negative
+ * dividends if the divisor variable type is unsigned.
+ */
#define DIV_ROUND_CLOSEST(x, divisor)( \
{ \
- typeof(divisor) __divisor = divisor; \
- (((x) + ((__divisor) / 2)) / (__divisor)); \
+ typeof(x) __x = x; \
+ typeof(divisor) __d = divisor; \
+ (((typeof(x))-1) > 0 || \
+ ((typeof(divisor))-1) > 0 || \
+ (((__x) > 0) == ((__d) > 0))) ? \
+ (((__x) + ((__d) / 2)) / (__d)) : \
+ (((__x) - ((__d) / 2)) / (__d)); \
} \
)
/*
@@ -45,19 +106,16 @@
} \
)
-/* The `const' in roundup() prevents gcc-3.3 from calling __divdi3 */
-#define roundup(x, y) ( \
-{ \
- const typeof(y) __y = y; \
- (((x) + (__y - 1)) / __y) * __y; \
-} \
-)
-#define rounddown(x, y) ( \
-{ \
- typeof(x) __x = (x); \
- __x - (__x % (y)); \
-} \
-)
+#define __STRUCT_FRACT(type) \
+struct type##_fract { \
+ __##type numerator; \
+ __##type denominator; \
+};
+__STRUCT_FRACT(s16)
+__STRUCT_FRACT(u16)
+__STRUCT_FRACT(s32)
+__STRUCT_FRACT(u32)
+#undef __STRUCT_FRACT
/* Calculate "x * n / d" without unnecessary overflow or loss of precision. */
#define mult_frac(x, n, d) \
@@ -71,16 +129,79 @@
q * n_ + r * n_ / d_; \
})
-#define abs(x) ({ \
- long __x = (x); \
- (__x < 0) ? -__x : __x; \
- })
+#define sector_div(a, b) do_div(a, b)
-#define abs64(x) ({ \
- s64 __x = (x); \
- (__x < 0) ? -__x : __x; \
- })
+/**
+ * abs - return absolute value of an argument
+ * @x: the value. If it is unsigned type, it is converted to signed type first.
+ * char is treated as if it was signed (regardless of whether it really is)
+ * but the macro's return type is preserved as char.
+ *
+ * Return: an absolute value of x.
+ */
+#define abs(x) __abs_choose_expr(x, long long, \
+ __abs_choose_expr(x, long, \
+ __abs_choose_expr(x, int, \
+ __abs_choose_expr(x, short, \
+ __abs_choose_expr(x, char, \
+ __builtin_choose_expr( \
+ __builtin_types_compatible_p(typeof(x), char), \
+ (char)({ signed char __x = (x); __x<0?-__x:__x; }), \
+ ((void)0)))))))
+#define __abs_choose_expr(x, type, other) __builtin_choose_expr( \
+ __builtin_types_compatible_p(typeof(x), signed type) || \
+ __builtin_types_compatible_p(typeof(x), unsigned type), \
+ ({ signed type __x = (x); __x < 0 ? -__x : __x; }), other)
+
+/**
+ * abs_diff - return absolute value of the difference between the arguments
+ * @a: the first argument
+ * @b: the second argument
+ *
+ * @a and @b have to be of the same type. With this restriction we compare
+ * signed to signed and unsigned to unsigned. The result is the subtraction
+ * the smaller of the two from the bigger, hence result is always a positive
+ * value.
+ *
+ * Return: an absolute value of the difference between the @a and @b.
+ */
+#define abs_diff(a, b) ({ \
+ typeof(a) __a = (a); \
+ typeof(b) __b = (b); \
+ (void)(&__a == &__b); \
+ __a > __b ? (__a - __b) : (__b - __a); \
+})
+
+/**
+ * reciprocal_scale - "scale" a value into range [0, ep_ro)
+ * @val: value
+ * @ep_ro: right open interval endpoint
+ *
+ * Perform a "reciprocal multiplication" in order to "scale" a value into
+ * range [0, @ep_ro), where the upper interval endpoint is right-open.
+ * This is useful, e.g. for accessing a index of an array containing
+ * @ep_ro elements, for example. Think of it as sort of modulus, only that
+ * the result isn't that of modulo. ;) Note that if initial input is a
+ * small value, then result will return 0.
+ *
+ * Return: a result based on @val in interval [0, @ep_ro).
+ */
+static inline u32 reciprocal_scale(u32 val, u32 ep_ro)
+{
+ return (u32)(((u64) val * ep_ro) >> 32);
+}
+
+u64 int_pow(u64 base, unsigned int exp);
unsigned long int_sqrt(unsigned long);
+#if BITS_PER_LONG < 64
+u32 int_sqrt64(u64 x);
+#else
+static inline u32 int_sqrt64(u64 x)
+{
+ return (u32)int_sqrt(x);
+}
#endif
+
+#endif /* _LINUX_MATH_H */
diff --git a/lib/math/Makefile b/lib/math/Makefile
index 71ab2b108689..197f92a097ed 100644
--- a/lib/math/Makefile
+++ b/lib/math/Makefile
@@ -3,4 +3,5 @@
obj-y += div64.o
pbl-y += div64.o
obj-y += rational.o
+obj-y += int_pow.o
obj-y += int_sqrt.o
diff --git a/lib/math/int_pow.c b/lib/math/int_pow.c
new file mode 100644
index 000000000000..0cf426e69bda
--- /dev/null
+++ b/lib/math/int_pow.c
@@ -0,0 +1,32 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * An integer based power function
+ *
+ * Derived from drivers/video/backlight/pwm_bl.c
+ */
+
+#include <linux/export.h>
+#include <linux/math.h>
+#include <linux/types.h>
+
+/**
+ * int_pow - computes the exponentiation of the given base and exponent
+ * @base: base which will be raised to the given power
+ * @exp: power to be raised to
+ *
+ * Computes: pow(base, exp), i.e. @base raised to the @exp power
+ */
+u64 int_pow(u64 base, unsigned int exp)
+{
+ u64 result = 1;
+
+ while (exp) {
+ if (exp & 1)
+ result *= base;
+ exp >>= 1;
+ base *= base;
+ }
+
+ return result;
+}
+EXPORT_SYMBOL_GPL(int_pow);
diff --git a/lib/math/int_sqrt.c b/lib/math/int_sqrt.c
index 105656d04661..f417e97003e1 100644
--- a/lib/math/int_sqrt.c
+++ b/lib/math/int_sqrt.c
@@ -1,17 +1,7 @@
-/*
- * This program is free software; you can redistribute it and/or
- * modify it under the terms of the GNU General Public License as
- * published by the Free Software Foundation; either version 2 of
- * the License, or (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- * GNU General Public License for more details.
- *
- */
+// SPDX-License-Identifier: GPL-2.0
#include <linux/math.h>
+#include <linux/limits.h>
#include <linux/export.h>
/**
@@ -42,3 +32,33 @@ unsigned long int_sqrt(unsigned long x)
return y;
}
EXPORT_SYMBOL(int_sqrt);
+
+#if BITS_PER_LONG < 64
+/**
+ * int_sqrt64 - strongly typed int_sqrt function when minimum 64 bit input
+ * is expected.
+ * @x: 64bit integer of which to calculate the sqrt
+ */
+u32 int_sqrt64(u64 x)
+{
+ u64 b, m, y = 0;
+
+ if (x <= ULONG_MAX)
+ return int_sqrt((unsigned long) x);
+
+ m = 1ULL << ((fls64(x) - 1) & ~1ULL);
+ while (m != 0) {
+ b = y + m;
+ y >>= 1;
+
+ if (x >= b) {
+ x -= b;
+ y += m;
+ }
+ m >>= 2;
+ }
+
+ return y;
+}
+EXPORT_SYMBOL(int_sqrt64);
+#endif
--
2.39.2
