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/* SPDX-License-Identifier: GPL-2.0-only */
/*
* Copyright (c) 2012-2014 The Linux Foundation. All rights reserved.
*/
#ifndef _LINUX_IOPOLL_H
#define _LINUX_IOPOLL_H
#include <linux/kernel.h>
#include <linux/types.h>
#include <linux/ktime.h>
#include <linux/delay.h>
#include <linux/errno.h>
#include <linux/io.h>
/**
* read_poll_timeout - Periodically poll an address until a condition is
* met or a timeout occurs
* @op: accessor function (takes @args as its arguments)
* @val: Variable to read the value into
* @cond: Break condition (usually involving @val)
* @sleep_us: Maximum time to sleep between reads in us (0
* tight-loops). Should be less than ~20ms since usleep_range
* is used (see Documentation/timers/timers-howto.rst).
* @timeout_us: Timeout in us, 0 means never timeout
* @sleep_before_read: if it is true, sleep @sleep_us before read.
* @args: arguments for @op poll
*
* Returns 0 on success and -ETIMEDOUT upon a timeout. In either
* case, the last read value at @args is stored in @val. Must not
* be called from atomic context if sleep_us or timeout_us are used.
*
* When available, you'll probably want to use one of the specialized
* macros defined below rather than this macro directly.
*/
#define read_poll_timeout(op, val, cond, sleep_us, timeout_us, \
sleep_before_read, args...) \
({ \
u64 __timeout_us = (timeout_us); \
unsigned long __sleep_us = (sleep_us); \
ktime_t __timeout = ktime_add_us(ktime_get(), __timeout_us); \
might_sleep_if((__sleep_us) != 0); \
if (sleep_before_read && __sleep_us) \
usleep_range((__sleep_us >> 2) + 1, __sleep_us); \
for (;;) { \
(val) = op(args); \
if (cond) \
break; \
if (__timeout_us && \
ktime_compare(ktime_get(), __timeout) > 0) { \
(val) = op(args); \
break; \
} \
if (__sleep_us) \
usleep_range((__sleep_us >> 2) + 1, __sleep_us); \
cpu_relax(); \
} \
(cond) ? 0 : -ETIMEDOUT; \
})
/**
* read_poll_timeout_atomic - Periodically poll an address until a condition is
* met or a timeout occurs
* @op: accessor function (takes @args as its arguments)
* @val: Variable to read the value into
* @cond: Break condition (usually involving @val)
* @delay_us: Time to udelay between reads in us (0 tight-loops). Should
* be less than ~10us since udelay is used (see
* Documentation/timers/timers-howto.rst).
* @timeout_us: Timeout in us, 0 means never timeout
* @delay_before_read: if it is true, delay @delay_us before read.
* @args: arguments for @op poll
*
* Returns 0 on success and -ETIMEDOUT upon a timeout. In either
* case, the last read value at @args is stored in @val.
*
* This macro does not rely on timekeeping. Hence it is safe to call even when
* timekeeping is suspended, at the expense of an underestimation of wall clock
* time, which is rather minimal with a non-zero delay_us.
*
* When available, you'll probably want to use one of the specialized
* macros defined below rather than this macro directly.
*/
#define read_poll_timeout_atomic(op, val, cond, delay_us, timeout_us, \
delay_before_read, args...) \
({ \
u64 __timeout_us = (timeout_us); \
s64 __left_ns = __timeout_us * NSEC_PER_USEC; \
unsigned long __delay_us = (delay_us); \
u64 __delay_ns = __delay_us * NSEC_PER_USEC; \
if (delay_before_read && __delay_us) { \
udelay(__delay_us); \
if (__timeout_us) \
__left_ns -= __delay_ns; \
} \
for (;;) { \
(val) = op(args); \
if (cond) \
break; \
if (__timeout_us && __left_ns < 0) { \
(val) = op(args); \
break; \
} \
if (__delay_us) { \
udelay(__delay_us); \
if (__timeout_us) \
__left_ns -= __delay_ns; \
} \
cpu_relax(); \
if (__timeout_us) \
__left_ns--; \
} \
(cond) ? 0 : -ETIMEDOUT; \
})
/**
* readx_poll_timeout - Periodically poll an address until a condition is met or a timeout occurs
* @op: accessor function (takes @addr as its only argument)
* @addr: Address to poll
* @val: Variable to read the value into
* @cond: Break condition (usually involving @val)
* @sleep_us: Maximum time to sleep between reads in us (0
* tight-loops). Should be less than ~20ms since usleep_range
* is used (see Documentation/timers/timers-howto.rst).
* @timeout_us: Timeout in us, 0 means never timeout
*
* Returns 0 on success and -ETIMEDOUT upon a timeout. In either
* case, the last read value at @addr is stored in @val. Must not
* be called from atomic context if sleep_us or timeout_us are used.
*
* When available, you'll probably want to use one of the specialized
* macros defined below rather than this macro directly.
*/
#define readx_poll_timeout(op, addr, val, cond, sleep_us, timeout_us) \
read_poll_timeout(op, val, cond, sleep_us, timeout_us, false, addr)
/**
* readx_poll_timeout_atomic - Periodically poll an address until a condition is met or a timeout occurs
* @op: accessor function (takes @addr as its only argument)
* @addr: Address to poll
* @val: Variable to read the value into
* @cond: Break condition (usually involving @val)
* @delay_us: Time to udelay between reads in us (0 tight-loops). Should
* be less than ~10us since udelay is used (see
* Documentation/timers/timers-howto.rst).
* @timeout_us: Timeout in us, 0 means never timeout
*
* Returns 0 on success and -ETIMEDOUT upon a timeout. In either
* case, the last read value at @addr is stored in @val.
*
* When available, you'll probably want to use one of the specialized
* macros defined below rather than this macro directly.
*/
#define readx_poll_timeout_atomic(op, addr, val, cond, delay_us, timeout_us) \
read_poll_timeout_atomic(op, val, cond, delay_us, timeout_us, false, addr)
#define readb_poll_timeout(addr, val, cond, delay_us, timeout_us) \
readx_poll_timeout(readb, addr, val, cond, delay_us, timeout_us)
#define readb_poll_timeout_atomic(addr, val, cond, delay_us, timeout_us) \
readx_poll_timeout_atomic(readb, addr, val, cond, delay_us, timeout_us)
#define readw_poll_timeout(addr, val, cond, delay_us, timeout_us) \
readx_poll_timeout(readw, addr, val, cond, delay_us, timeout_us)
#define readw_poll_timeout_atomic(addr, val, cond, delay_us, timeout_us) \
readx_poll_timeout_atomic(readw, addr, val, cond, delay_us, timeout_us)
#define readl_poll_timeout(addr, val, cond, delay_us, timeout_us) \
readx_poll_timeout(readl, addr, val, cond, delay_us, timeout_us)
#define readl_poll_timeout_atomic(addr, val, cond, delay_us, timeout_us) \
readx_poll_timeout_atomic(readl, addr, val, cond, delay_us, timeout_us)
#define readq_poll_timeout(addr, val, cond, delay_us, timeout_us) \
readx_poll_timeout(readq, addr, val, cond, delay_us, timeout_us)
#define readq_poll_timeout_atomic(addr, val, cond, delay_us, timeout_us) \
readx_poll_timeout_atomic(readq, addr, val, cond, delay_us, timeout_us)
#define readb_relaxed_poll_timeout(addr, val, cond, delay_us, timeout_us) \
readx_poll_timeout(readb_relaxed, addr, val, cond, delay_us, timeout_us)
#define readb_relaxed_poll_timeout_atomic(addr, val, cond, delay_us, timeout_us) \
readx_poll_timeout_atomic(readb_relaxed, addr, val, cond, delay_us, timeout_us)
#define readw_relaxed_poll_timeout(addr, val, cond, delay_us, timeout_us) \
readx_poll_timeout(readw_relaxed, addr, val, cond, delay_us, timeout_us)
#define readw_relaxed_poll_timeout_atomic(addr, val, cond, delay_us, timeout_us) \
readx_poll_timeout_atomic(readw_relaxed, addr, val, cond, delay_us, timeout_us)
#define readl_relaxed_poll_timeout(addr, val, cond, delay_us, timeout_us) \
readx_poll_timeout(readl_relaxed, addr, val, cond, delay_us, timeout_us)
#define readl_relaxed_poll_timeout_atomic(addr, val, cond, delay_us, timeout_us) \
readx_poll_timeout_atomic(readl_relaxed, addr, val, cond, delay_us, timeout_us)
#define readq_relaxed_poll_timeout(addr, val, cond, delay_us, timeout_us) \
readx_poll_timeout(readq_relaxed, addr, val, cond, delay_us, timeout_us)
#define readq_relaxed_poll_timeout_atomic(addr, val, cond, delay_us, timeout_us) \
readx_poll_timeout_atomic(readq_relaxed, addr, val, cond, delay_us, timeout_us)
#endif /* _LINUX_IOPOLL_H */
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