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git.proxmox.com Git - mirror_ubuntu-eoan-kernel.git/blob - arch/powerpc/include/asm/delay.h
1 #ifndef _ASM_POWERPC_DELAY_H
2 #define _ASM_POWERPC_DELAY_H
5 #include <linux/processor.h>
9 * Copyright 1996, Paul Mackerras.
10 * Copyright (C) 2009 Freescale Semiconductor, Inc. All rights reserved.
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.
17 * PPC64 Support added by Dave Engebretsen, Todd Inglett, Mike Corrigan,
21 extern void __delay(unsigned long loops
);
22 extern void udelay(unsigned long usecs
);
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.
30 * Since there is no 32bit overflow issue on 64bit kernels, just call
34 #define mdelay(n) udelay((n) * 1000)
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
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.
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.
55 * gcc will optimize out the if-statement if @delay is a constant.
57 #define spin_event_timeout(condition, timeout, delay) \
59 typeof(condition) __ret; \
60 unsigned long __loops = tb_ticks_per_usec * timeout; \
61 unsigned long __start = get_tbl(); \
64 while (!(__ret = (condition)) && \
65 (tb_ticks_since(__start) <= __loops)) \
69 while (!(__ret = (condition)) && \
70 (tb_ticks_since(__start) <= __loops)) \
75 __ret = (condition); \
79 #endif /* __KERNEL__ */
80 #endif /* _ASM_POWERPC_DELAY_H */