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/delay.h>
12 #include <linux/export.h>
13 #include <linux/param.h>
14 #include <linux/smp.h>
15 #include <linux/stringify.h>
16
17 #include <asm/asm.h>
18 #include <asm/compiler.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
25
26 #ifndef CONFIG_HAVE_PLAT_DELAY
27
28 void __delay(unsigned long loops)
29 {
30 __asm__ __volatile__ (
31 " .set noreorder \n"
32 " .align 3 \n"
33 "1: bnez %0, 1b \n"
34 " " __stringify(LONG_SUBU) " %0, %1 \n"
35 " .set reorder \n"
36 : "=r" (loops)
37 : GCC_DADDI_IMM_ASM() (1), "" (loops));
38 }
39 EXPORT_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
52 void __udelay(unsigned long us)
53 {
54 unsigned int lpj = raw_current_cpu_data.udelay_val;
55
56 __delay((us * 0x000010c7ull * HZ * lpj) >> 32);
57 }
58 EXPORT_SYMBOL(__udelay);
59
60 void __ndelay(unsigned long ns)
61 {
62 unsigned int lpj = raw_current_cpu_data.udelay_val;
63
64 __delay((ns * 0x00000005ull * HZ * lpj) >> 32);
65 }
66 EXPORT_SYMBOL(__ndelay);
67
68 #endif
69
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