1 // SPDX-License-Identifier: GPL-2.0-only !! 1 /*
2 /* Copyright Altera Corporation (C) 2014. All !! 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
3 */ 10 */
>> 11 #include <linux/export.h>
>> 12 #include <linux/param.h>
>> 13 #include <linux/smp.h>
>> 14 #include <linux/stringify.h>
>> 15
>> 16 #include <asm/asm.h>
>> 17 #include <asm/compiler.h>
>> 18 #include <asm/war.h>
>> 19
>> 20 #ifndef CONFIG_CPU_DADDI_WORKAROUNDS
>> 21 #define GCC_DADDI_IMM_ASM() "I"
>> 22 #else
>> 23 #define GCC_DADDI_IMM_ASM() "r"
>> 24 #endif
4 25
5 #include <linux/module.h> !! 26 void __delay(unsigned long loops)
6 #include <asm/delay.h> <<
7 #include <asm/param.h> <<
8 #include <asm/processor.h> <<
9 #include <asm/timex.h> <<
10 <<
11 void __delay(unsigned long cycles) <<
12 { 27 {
13 cycles_t start = get_cycles(); !! 28 __asm__ __volatile__ (
14 !! 29 " .set noreorder \n"
15 while ((get_cycles() - start) < cycles !! 30 " .align 3 \n"
16 cpu_relax(); !! 31 "1: bnez %0, 1b \n"
>> 32 " " __stringify(LONG_SUBU) " %0, %1 \n"
>> 33 " .set reorder \n"
>> 34 : "=r" (loops)
>> 35 : GCC_DADDI_IMM_ASM() (1), "" (loops));
17 } 36 }
18 EXPORT_SYMBOL(__delay); 37 EXPORT_SYMBOL(__delay);
19 38
20 void __const_udelay(unsigned long xloops) !! 39 /*
21 { !! 40 * Division by multiplication: you don't have to worry about
22 u64 loops; !! 41 * loss of precision.
23 !! 42 *
24 loops = (u64)xloops * loops_per_jiffy !! 43 * Use only for very small delays ( < 1 msec). Should probably use a
25 !! 44 * lookup table, really, as the multiplications take much too long with
26 __delay(loops >> 32); !! 45 * short delays. This is a "reasonable" implementation, though (and the
27 } !! 46 * first constant multiplications gets optimized away if the delay is
28 EXPORT_SYMBOL(__const_udelay); !! 47 * a constant)
>> 48 */
29 49
30 void __udelay(unsigned long usecs) !! 50 void __udelay(unsigned long us)
31 { 51 {
32 __const_udelay(usecs * 0x10C7UL); /* 2 !! 52 unsigned int lpj = raw_current_cpu_data.udelay_val;
>> 53
>> 54 __delay((us * 0x000010c7ull * HZ * lpj) >> 32);
33 } 55 }
34 EXPORT_SYMBOL(__udelay); 56 EXPORT_SYMBOL(__udelay);
35 57
36 void __ndelay(unsigned long nsecs) !! 58 void __ndelay(unsigned long ns)
37 { 59 {
38 __const_udelay(nsecs * 0x5UL); /* 2**3 !! 60 unsigned int lpj = raw_current_cpu_data.udelay_val;
>> 61
>> 62 __delay((ns * 0x00000005ull * HZ * lpj) >> 32);
39 } 63 }
40 EXPORT_SYMBOL(__ndelay); 64 EXPORT_SYMBOL(__ndelay);
41 65
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