[linux-2.6-block.git] / arch / powerpc / include / asm / delay.h

#ifndef _ASM_POWERPC_DELAY_H
#define _ASM_POWERPC_DELAY_H
#ifdef __KERNEL__

#include <linux/processor.h>
#include <asm/time.h>

/*
 * Copyright 1996, Paul Mackerras.
 * Copyright (C) 2009 Freescale Semiconductor, Inc. All rights reserved.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version
 * 2 of the License, or (at your option) any later version.
 *
 * PPC64 Support added by Dave Engebretsen, Todd Inglett, Mike Corrigan,
 * Anton Blanchard.
 */

extern void __delay(unsigned long loops);
extern void udelay(unsigned long usecs);

/*
 * On shared processor machines the generic implementation of mdelay can
 * result in large errors. While each iteration of the loop inside mdelay
 * is supposed to take 1ms, the hypervisor could sleep our partition for
 * longer (eg 10ms). With the right timing these errors can add up.
 *
 * Since there is no 32bit overflow issue on 64bit kernels, just call
 * udelay directly.
 */
#ifdef CONFIG_PPC64
#define mdelay(n)	udelay((n) * 1000)
#endif

/**
 * spin_event_timeout - spin until a condition gets true or a timeout elapses
 * @condition: a C expression to evalate
 * @timeout: timeout, in microseconds
 * @delay: the number of microseconds to delay between each evaluation of
 *         @condition
 *
 * The process spins until the condition evaluates to true (non-zero) or the
 * timeout elapses.  The return value of this macro is the value of
 * @condition when the loop terminates. This allows you to determine the cause
 * of the loop terminates.  If the return value is zero, then you know a
 * timeout has occurred.
 *
 * This primary purpose of this macro is to poll on a hardware register
 * until a status bit changes.  The timeout ensures that the loop still
 * terminates even if the bit never changes.  The delay is for devices that
 * need a delay in between successive reads.
 *
 * gcc will optimize out the if-statement if @delay is a constant.
 */
#define spin_event_timeout(condition, timeout, delay)                          \
({                                                                             \
	typeof(condition) __ret;                                               \
	unsigned long __loops = tb_ticks_per_usec * timeout;                   \
	unsigned long __start = get_tbl();                                     \
                                                                               \
	if (delay) {                                                           \
		while (!(__ret = (condition)) &&                               \
				(tb_ticks_since(__start) <= __loops))          \
			udelay(delay);                                         \
	} else {                                                               \
		spin_begin();                                                  \
		while (!(__ret = (condition)) &&                               \
				(tb_ticks_since(__start) <= __loops))          \
			spin_cpu_relax();                                      \
		spin_end();                                                    \
	}                                                                      \
	if (!__ret)                                                            \
		__ret = (condition);                                           \
	__ret;		                                                       \
})

#endif /* __KERNEL__ */
#endif /* _ASM_POWERPC_DELAY_H */
Commit	Line	Data
c55377ee PM	1	#ifndef _ASM_POWERPC_DELAY_H
c55377ee PM	2	#define _ASM_POWERPC_DELAY_H
88ced031	3	#ifdef __KERNEL__
1da177e4	4
4e287e65	5	#include <linux/processor.h>
9317726d TT	6	#include <asm/time.h>
9317726d TT	7
1da177e4 LT	8	/*
1da177e4 LT	9	* Copyright 1996, Paul Mackerras.
9317726d	10	* Copyright (C) 2009 Freescale Semiconductor, Inc. All rights reserved.
1da177e4 LT	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
6defa38b PM	21	extern void __delay(unsigned long loops);
6defa38b PM	22	extern void udelay(unsigned long usecs);
1da177e4	23
1e92a550 AB	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
9317726d TT	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(); \
4e287e65 NP	62	\
	63	if (delay) { \
	64	while (!(__ret = (condition)) && \
	65	(tb_ticks_since(__start) <= __loops)) \
9317726d	66	udelay(delay); \
4e287e65 NP	67	} else { \
	68	spin_begin(); \
	69	while (!(__ret = (condition)) && \
	70	(tb_ticks_since(__start) <= __loops)) \
	71	spin_cpu_relax(); \
	72	spin_end(); \
	73	} \
ad9064d5 GL	74	if (!__ret) \
ad9064d5 GL	75	__ret = (condition); \
9317726d TT	76	__ret; \
	77	})
	78
88ced031	79	#endif /* __KERNEL__ */
c55377ee	80	#endif /* _ASM_POWERPC_DELAY_H */