1 #ifndef _ASM_POWERPC_DELAY_H 2 #define _ASM_POWERPC_DELAY_H 3 #ifdef __KERNEL__ 4 5 #include <asm/time.h> 6 7 /* 8 * Copyright 1996, Paul Mackerras. 9 * Copyright (C) 2009 Freescale Semiconductor, Inc. All rights reserved. 10 * 11 * This program is free software; you can redistribute it and/or 12 * modify it under the terms of the GNU General Public License 13 * as published by the Free Software Foundation; either version 14 * 2 of the License, or (at your option) any later version. 15 * 16 * PPC64 Support added by Dave Engebretsen, Todd Inglett, Mike Corrigan, 17 * Anton Blanchard. 18 */ 19 20 extern void __delay(unsigned long loops); 21 extern void udelay(unsigned long usecs); 22 23 /* 24 * On shared processor machines the generic implementation of mdelay can 25 * result in large errors. While each iteration of the loop inside mdelay 26 * is supposed to take 1ms, the hypervisor could sleep our partition for 27 * longer (eg 10ms). With the right timing these errors can add up. 28 * 29 * Since there is no 32bit overflow issue on 64bit kernels, just call 30 * udelay directly. 31 */ 32 #ifdef CONFIG_PPC64 33 #define mdelay(n) udelay((n) * 1000) 34 #endif 35 36 /** 37 * spin_event_timeout - spin until a condition gets true or a timeout elapses 38 * @condition: a C expression to evalate 39 * @timeout: timeout, in microseconds 40 * @delay: the number of microseconds to delay between each evaluation of 41 * @condition 42 * 43 * The process spins until the condition evaluates to true (non-zero) or the 44 * timeout elapses. The return value of this macro is the value of 45 * @condition when the loop terminates. This allows you to determine the cause 46 * of the loop terminates. If the return value is zero, then you know a 47 * timeout has occurred. 48 * 49 * This primary purpose of this macro is to poll on a hardware register 50 * until a status bit changes. The timeout ensures that the loop still 51 * terminates even if the bit never changes. The delay is for devices that 52 * need a delay in between successive reads. 53 * 54 * gcc will optimize out the if-statement if @delay is a constant. 55 */ 56 #define spin_event_timeout(condition, timeout, delay) \ 57 ({ \ 58 typeof(condition) __ret; \ 59 unsigned long __loops = tb_ticks_per_usec * timeout; \ 60 unsigned long __start = get_tbl(); \ 61 while (!(__ret = (condition)) && (tb_ticks_since(__start) <= __loops)) \ 62 if (delay) \ 63 udelay(delay); \ 64 else \ 65 cpu_relax(); \ 66 if (!__ret) \ 67 __ret = (condition); \ 68 __ret; \ 69 }) 70 71 #endif /* __KERNEL__ */ 72 #endif /* _ASM_POWERPC_DELAY_H */ 73