tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
1/*
2 * This file is subject to the terms and conditions of the GNU General Public
3 * License. See the file "COPYING" in the main directory of this archive
4 * for more details.
5 *
6 * Copyright (C) 1994 by Waldorf Electronics
7 * Copyright (C) 1995 - 2000, 01, 03 by Ralf Baechle
8 * Copyright (C) 1999, 2000 Silicon Graphics, Inc.
9 * Copyright (C) 2007, 2014 Maciej W. Rozycki
10 */
11#include <linux/module.h>
12#include <linux/param.h>
13#include <linux/smp.h>
14
15#include <asm/compiler.h>
16#include <asm/war.h>
17
18#ifndef CONFIG_CPU_DADDI_WORKAROUNDS
19#define GCC_DADDI_IMM_ASM() "I"
20#else
21#define GCC_DADDI_IMM_ASM() "r"
22#endif
23
24void __delay(unsigned long loops)
25{
26 __asm__ __volatile__ (
27 " .set noreorder \n"
28 " .align 3 \n"
29 "1: bnez %0, 1b \n"
30#if BITS_PER_LONG == 32
31 " subu %0, %1 \n"
32#else
33 " dsubu %0, %1 \n"
34#endif
35 " .set reorder \n"
36 : "=r" (loops)
37 : GCC_DADDI_IMM_ASM() (1), "0" (loops));
38}
39EXPORT_SYMBOL(__delay);
40
41/*
42 * Division by multiplication: you don't have to worry about
43 * loss of precision.
44 *
45 * Use only for very small delays ( < 1 msec). Should probably use a
46 * lookup table, really, as the multiplications take much too long with
47 * short delays. This is a "reasonable" implementation, though (and the
48 * first constant multiplications gets optimized away if the delay is
49 * a constant)
50 */
51
52void __udelay(unsigned long us)
53{
54 unsigned int lpj = raw_current_cpu_data.udelay_val;
55
56 __delay((us * 0x000010c7ull * HZ * lpj) >> 32);
57}
58EXPORT_SYMBOL(__udelay);
59
60void __ndelay(unsigned long ns)
61{
62 unsigned int lpj = raw_current_cpu_data.udelay_val;
63
64 __delay((ns * 0x00000005ull * HZ * lpj) >> 32);
65}
66EXPORT_SYMBOL(__ndelay);