From c8b0c33b03ac072413b27bed2bdae2ae27426f3a Mon Sep 17 00:00:00 2001
From: Doug Moore <dougm@FreeBSD.org>
Date: Mon, 24 Jun 2024 02:00:31 -0500
Subject: log2: move log2 functions from linuxkpi to libkern

Linux has a header file that defines an ilog2 function and some simple
functions/macros that use it: roundup_pow_of_two, is_power_of_2,
rounddown_pow_of_two, and order_base_2.  This change moves three of
those simple functions (all but is_power_of_2) from linuxkpi to
libkern.  It also deletes a few implementations of these functions
that have previously been copied into code for various device drivers,
so that they can use the libkern version.  The is_power_of_2 macro was
not moved because powerof2 in param.h provides almost the same service
already (except that they disagree about whether 0 is a power of two).

Since the linux definitions of these functions were copied into
FreeBSD 11 years ago, linux has improved them, and this change
provides those improvements.  In particular, a giant table of log
values for evaluating ilog2 for constant values is no longer
necessary.

Reviewed by:	alc, markj (previous version)
Differential Revision:	https://reviews.freebsd.org/D45536
---
 sys/dev/drm2/drm_os_freebsd.h |  7 -------
 sys/dev/mana/gdma_util.h      | 12 ------------
 sys/dev/qlnx/qlnxe/bcm_osal.h | 18 ------------------
 3 files changed, 37 deletions(-)

(limited to 'sys/dev')

diff --git a/sys/dev/drm2/drm_os_freebsd.h b/sys/dev/drm2/drm_os_freebsd.h
index 58523a33da2a..b2a2e82b748b 100644
--- a/sys/dev/drm2/drm_os_freebsd.h
+++ b/sys/dev/drm2/drm_os_freebsd.h
@@ -234,13 +234,6 @@ typedef void			irqreturn_t;
 #define	div_u64(n, d)		((n) / (d))
 #define	hweight32(i)		bitcount32(i)
 
-static inline unsigned long
-roundup_pow_of_two(unsigned long x)
-{
-
-	return (1UL << flsl(x - 1));
-}
-
 /**
  * ror32 - rotate a 32-bit value right
  * @word: value to rotate
diff --git a/sys/dev/mana/gdma_util.h b/sys/dev/mana/gdma_util.h
index 37c2653d5ec9..1efa315bbcfe 100644
--- a/sys/dev/mana/gdma_util.h
+++ b/sys/dev/mana/gdma_util.h
@@ -170,18 +170,6 @@ find_first_zero_bit(const unsigned long *p, unsigned long max)
 	return (max);
 }
 
-static inline unsigned long
-roundup_pow_of_two(unsigned long x)
-{
-	return (1UL << flsl(x - 1));
-}
-
-static inline int
-is_power_of_2(unsigned long n)
-{
-	return (n == roundup_pow_of_two(n));
-}
-
 struct completion {
 	unsigned int done;
 	struct mtx lock;
diff --git a/sys/dev/qlnx/qlnxe/bcm_osal.h b/sys/dev/qlnx/qlnxe/bcm_osal.h
index c820532c9e0a..7148fd3f6215 100644
--- a/sys/dev/qlnx/qlnxe/bcm_osal.h
+++ b/sys/dev/qlnx/qlnxe/bcm_osal.h
@@ -102,24 +102,6 @@ extern void qlnx_vf_flr_update(void *p_hwfn);
 
 #ifndef QLNX_RDMA
 
-static __inline unsigned long
-roundup_pow_of_two(unsigned long x)
-{
-	return (1UL << flsl(x - 1));
-}
-
-static __inline int
-is_power_of_2(unsigned long n)
-{
-	return (n == roundup_pow_of_two(n));
-}
-
-static __inline unsigned long
-rounddown_pow_of_two(unsigned long x)
-{
-	return (1UL << (flsl(x) - 1));
-}
-
 #define max_t(type, val1, val2) \
 	((type)(val1) > (type)(val2) ? (type)(val1) : (val2))
 #define min_t(type, val1, val2) \
-- 
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