projects / deliverable / linux.git / blame
| Commit | Line | Data |
|---|---|---|
| 216f0348 MS |
1 | /* |
| 2 | * include/asm-microblaze/delay.h | |
| 3 | * | |
| 4 | * This file is subject to the terms and conditions of the GNU General Public | |
| 5 | * License. See the file "COPYING" in the main directory of this archive | |
| 6 | * for more details. | |
| 7 | * | |
| 8 | * Copyright (C) 2008 Michal Simek | |
| 9 | * Copyright (C) 2007 John Williams | |
| 10 | * Copyright (C) 2006 Atmark Techno, Inc. | |
| 11 | */ | |
| 12 | ||
| 13 | #ifndef _ASM_MICROBLAZE_DELAY_H | |
| 14 | #define _ASM_MICROBLAZE_DELAY_H | |
| 15 | ||
| 16 | extern inline void __delay(unsigned long loops) | |
| 17 | { | |
| 18 | asm volatile ("# __delay \n\t" \ | |
| 19 | "1: addi %0, %0, -1\t\n" \ | |
| 20 | "bneid %0, 1b \t\n" \ | |
| 21 | "nop \t\n" | |
| 22 | : "=r" (loops) | |
| 23 | : "0" (loops)); | |
| 24 | } | |
| 25 | ||
| 26 | /* | |
| 27 | * Note that 19 * 226 == 4294 ==~ 2^32 / 10^6, so | |
| 28 | * loops = (4294 * usecs * loops_per_jiffy * HZ) / 2^32. | |
| 29 | * | |
| 30 | * The mul instruction gives us loops = (a * b) / 2^32. | |
| 31 | * We choose a = usecs * 19 * HZ and b = loops_per_jiffy * 226 | |
| 32 | * because this lets us support a wide range of HZ and | |
| 33 | * loops_per_jiffy values without either a or b overflowing 2^32. | |
| 34 | * Thus we need usecs * HZ <= (2^32 - 1) / 19 = 226050910 and | |
| 35 | * loops_per_jiffy <= (2^32 - 1) / 226 = 19004280 | |
| 36 | * (which corresponds to ~3800 bogomips at HZ = 100). | |
| 37 | * -- paulus | |
| 38 | */ | |
| 39 | #define __MAX_UDELAY (226050910UL/HZ) /* maximum udelay argument */ | |
| 40 | #define __MAX_NDELAY (4294967295UL/HZ) /* maximum ndelay argument */ | |
| 41 | ||
| 42 | extern unsigned long loops_per_jiffy; | |
| 43 | ||
| 44 | extern inline void __udelay(unsigned int x) | |
| 45 | { | |
| 46 | ||
| 47 | unsigned long long tmp = | |
| 48 | (unsigned long long)x * (unsigned long long)loops_per_jiffy \ | |
| 49 | * 226LL; | |
| 50 | unsigned loops = tmp >> 32; | |
| 51 | ||
| 52 | /* | |
| 53 | __asm__("mulxuu %0,%1,%2" : "=r" (loops) : | |
| 54 | "r" (x), "r" (loops_per_jiffy * 226)); | |
| 55 | */ | |
| 56 | __delay(loops); | |
| 57 | } | |
| 58 | ||
| 59 | extern void __bad_udelay(void); /* deliberately undefined */ | |
| 60 | extern void __bad_ndelay(void); /* deliberately undefined */ | |
| 61 | ||
| 62 | #define udelay(n) (__builtin_constant_p(n) ? \ | |
| 63 | ((n) > __MAX_UDELAY ? __bad_udelay() : __udelay((n) * (19 * HZ))) : \ | |
| 64 | __udelay((n) * (19 * HZ))) | |
| 65 | ||
| 66 | #define ndelay(n) (__builtin_constant_p(n) ? \ | |
| 67 | ((n) > __MAX_NDELAY ? __bad_ndelay() : __udelay((n) * HZ)) : \ | |
| 68 | __udelay((n) * HZ)) | |
| 69 | ||
| 70 | #define muldiv(a, b, c) (((a)*(b))/(c)) | |
| 71 | ||
| 72 | #endif /* _ASM_MICROBLAZE_DELAY_H */ |