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

/* SPDX-License-Identifier: GPL-2.0-or-later */
#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.
 *
 * 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 = mftb();                                     \
                                                                               \
	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
2874c5fd	1	/* SPDX-License-Identifier: GPL-2.0-or-later */
c55377ee PM	2	#ifndef _ASM_POWERPC_DELAY_H
c55377ee PM	3	#define _ASM_POWERPC_DELAY_H
88ced031	4	#ifdef __KERNEL__
1da177e4	5
4e287e65	6	#include <linux/processor.h>
9317726d TT	7	#include <asm/time.h>
9317726d TT	8
1da177e4 LT	9	/*
1da177e4 LT	10	* Copyright 1996, Paul Mackerras.
9317726d	11	* Copyright (C) 2009 Freescale Semiconductor, Inc. All rights reserved.
1da177e4	12	*
1da177e4 LT	13	* PPC64 Support added by Dave Engebretsen, Todd Inglett, Mike Corrigan,
	14	* Anton Blanchard.
	15	*/
	16
6defa38b PM	17	extern void __delay(unsigned long loops);
6defa38b PM	18	extern void udelay(unsigned long usecs);
1da177e4	19
1e92a550 AB	20	/*
	21	* On shared processor machines the generic implementation of mdelay can
	22	* result in large errors. While each iteration of the loop inside mdelay
	23	* is supposed to take 1ms, the hypervisor could sleep our partition for
	24	* longer (eg 10ms). With the right timing these errors can add up.
	25	*
	26	* Since there is no 32bit overflow issue on 64bit kernels, just call
	27	* udelay directly.
	28	*/
	29	#ifdef CONFIG_PPC64
	30	#define mdelay(n) udelay((n) * 1000)
	31	#endif
	32
9317726d TT	33	/**
	34	* spin_event_timeout - spin until a condition gets true or a timeout elapses
	35	* @condition: a C expression to evalate
	36	* @timeout: timeout, in microseconds
	37	* @delay: the number of microseconds to delay between each evaluation of
	38	* @condition
	39	*
	40	* The process spins until the condition evaluates to true (non-zero) or the
	41	* timeout elapses. The return value of this macro is the value of
	42	* @condition when the loop terminates. This allows you to determine the cause
	43	* of the loop terminates. If the return value is zero, then you know a
	44	* timeout has occurred.
	45	*
	46	* This primary purpose of this macro is to poll on a hardware register
	47	* until a status bit changes. The timeout ensures that the loop still
	48	* terminates even if the bit never changes. The delay is for devices that
	49	* need a delay in between successive reads.
	50	*
	51	* gcc will optimize out the if-statement if @delay is a constant.
	52	*/
	53	#define spin_event_timeout(condition, timeout, delay) \
	54	({ \
	55	typeof(condition) __ret; \
	56	unsigned long __loops = tb_ticks_per_usec * timeout; \
942e8911	57	unsigned long __start = mftb(); \
4e287e65 NP	58	\
	59	if (delay) { \
	60	while (!(__ret = (condition)) && \
	61	(tb_ticks_since(__start) <= __loops)) \
9317726d	62	udelay(delay); \
4e287e65 NP	63	} else { \
	64	spin_begin(); \
	65	while (!(__ret = (condition)) && \
	66	(tb_ticks_since(__start) <= __loops)) \
	67	spin_cpu_relax(); \
	68	spin_end(); \
	69	} \
ad9064d5 GL	70	if (!__ret) \
ad9064d5 GL	71	__ret = (condition); \
9317726d TT	72	__ret; \
	73	})
	74
88ced031	75	#endif /* __KERNEL__ */
c55377ee	76	#endif /* _ASM_POWERPC_DELAY_H */