1 #ifndef _ASM_POWERPC_DELAY_H 2 #define _ASM_POWERPC_DELAY_H 3 #ifdef __KERNEL__ 4 5 #include <linux/processor.h> 6 #include <asm/time.h> 7 8 /* 9 * Copyright 1996, Paul Mackerras. 10 * Copyright (C) 2009 Freescale Semiconductor, Inc. All rights reserved. 11 * 12 * This program is free software; you can redistribute it and/or 13 * modify it under the terms of the GNU General Public License 14 * as published by the Free Software Foundation; either version 15 * 2 of the License, or (at your option) any later version. 16 * 17 * PPC64 Support added by Dave Engebretsen, Todd Inglett, Mike Corrigan, 18 * Anton Blanchard. 19 */ 20 21 extern void __delay(unsigned long loops); 22 extern void udelay(unsigned long usecs); 23 24 /* 25 * On shared processor machines the generic implementation of mdelay can 26 * result in large errors. While each iteration of the loop inside mdelay 27 * is supposed to take 1ms, the hypervisor could sleep our partition for 28 * longer (eg 10ms). With the right timing these errors can add up. 29 * 30 * Since there is no 32bit overflow issue on 64bit kernels, just call 31 * udelay directly. 32 */ 33 #ifdef CONFIG_PPC64 34 #define mdelay(n) udelay((n) * 1000) 35 #endif 36 37 /** 38 * spin_event_timeout - spin until a condition gets true or a timeout elapses 39 * @condition: a C expression to evalate 40 * @timeout: timeout, in microseconds 41 * @delay: the number of microseconds to delay between each evaluation of 42 * @condition 43 * 44 * The process spins until the condition evaluates to true (non-zero) or the 45 * timeout elapses. The return value of this macro is the value of 46 * @condition when the loop terminates. This allows you to determine the cause 47 * of the loop terminates. If the return value is zero, then you know a 48 * timeout has occurred. 49 * 50 * This primary purpose of this macro is to poll on a hardware register 51 * until a status bit changes. The timeout ensures that the loop still 52 * terminates even if the bit never changes. The delay is for devices that 53 * need a delay in between successive reads. 54 * 55 * gcc will optimize out the if-statement if @delay is a constant. 56 */ 57 #define spin_event_timeout(condition, timeout, delay) \ 58 ({ \ 59 typeof(condition) __ret; \ 60 unsigned long __loops = tb_ticks_per_usec * timeout; \ 61 unsigned long __start = get_tbl(); \ 62 \ 63 if (delay) { \ 64 while (!(__ret = (condition)) && \ 65 (tb_ticks_since(__start) <= __loops)) \ 66 udelay(delay); \ 67 } else { \ 68 spin_begin(); \ 69 while (!(__ret = (condition)) && \ 70 (tb_ticks_since(__start) <= __loops)) \ 71 spin_cpu_relax(); \ 72 spin_end(); \ 73 } \ 74 if (!__ret) \ 75 __ret = (condition); \ 76 __ret; \ 77 }) 78 79 #endif /* __KERNEL__ */ 80 #endif /* _ASM_POWERPC_DELAY_H */ 81