Linux 5.7.6
[linux/fpc-iii.git] / arch / mips / lib / delay.c
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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.
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
11 #include <linux/delay.h>
12 #include <linux/export.h>
13 #include <linux/param.h>
14 #include <linux/smp.h>
15 #include <linux/stringify.h>
17 #include <asm/asm.h>
18 #include <asm/compiler.h>
19 #include <asm/war.h>
21 #ifndef CONFIG_CPU_DADDI_WORKAROUNDS
22 #define GCC_DADDI_IMM_ASM() "I"
23 #else
24 #define GCC_DADDI_IMM_ASM() "r"
25 #endif
27 #ifndef CONFIG_HAVE_PLAT_DELAY
29 void __delay(unsigned long loops)
31 __asm__ __volatile__ (
32 " .set noreorder \n"
33 " .align 3 \n"
34 "1: bnez %0, 1b \n"
35 " " __stringify(LONG_SUBU) " %0, %1 \n"
36 " .set reorder \n"
37 : "=r" (loops)
38 : GCC_DADDI_IMM_ASM() (1), "0" (loops));
40 EXPORT_SYMBOL(__delay);
43 * Division by multiplication: you don't have to worry about
44 * loss of precision.
46 * Use only for very small delays ( < 1 msec). Should probably use a
47 * lookup table, really, as the multiplications take much too long with
48 * short delays. This is a "reasonable" implementation, though (and the
49 * first constant multiplications gets optimized away if the delay is
50 * a constant)
53 void __udelay(unsigned long us)
55 unsigned int lpj = raw_current_cpu_data.udelay_val;
57 __delay((us * 0x000010c7ull * HZ * lpj) >> 32);
59 EXPORT_SYMBOL(__udelay);
61 void __ndelay(unsigned long ns)
63 unsigned int lpj = raw_current_cpu_data.udelay_val;
65 __delay((ns * 0x00000005ull * HZ * lpj) >> 32);
67 EXPORT_SYMBOL(__ndelay);
69 #endif