diff options
Diffstat (limited to 'include/linux/iopoll.h')
| -rw-r--r-- | include/linux/iopoll.h | 211 |
1 files changed, 162 insertions, 49 deletions
diff --git a/include/linux/iopoll.h b/include/linux/iopoll.h index b1d861caca16..bdd2e0652bc3 100644 --- a/include/linux/iopoll.h +++ b/include/linux/iopoll.h @@ -1,15 +1,6 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ /* * Copyright (c) 2012-2014 The Linux Foundation. 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 version 2 and - * only version 2 as published by the Free Software Foundation. - * - * This program is distributed in the hope that it will be useful, - * but WITHOUT ANY WARRANTY; without even the implied warranty of - * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the - * GNU General Public License for more details. - * */ #ifndef _LINUX_IOPOLL_H @@ -23,81 +14,203 @@ #include <linux/io.h> /** - * 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.txt). - * @timeout_us: Timeout in us, 0 means never timeout + * poll_timeout_us - Periodically poll and perform an operation until + * a condition is met or a timeout occurs * - * 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. + * @op: Operation + * @cond: Break condition + * @sleep_us: Maximum time to sleep between operations in us (0 tight-loops). + * Please read usleep_range() function description for details and + * limitations. + * @timeout_us: Timeout in us, 0 means never timeout + * @sleep_before_op: if it is true, sleep @sleep_us before operation. * * When available, you'll probably want to use one of the specialized * macros defined below rather than this macro directly. + * + * Returns: 0 on success and -ETIMEDOUT upon a timeout. Must not + * be called from atomic context if sleep_us or timeout_us are used. */ -#define readx_poll_timeout(op, addr, val, cond, sleep_us, timeout_us) \ +#define poll_timeout_us(op, cond, sleep_us, timeout_us, sleep_before_op) \ ({ \ u64 __timeout_us = (timeout_us); \ unsigned long __sleep_us = (sleep_us); \ ktime_t __timeout = ktime_add_us(ktime_get(), __timeout_us); \ + int ___ret; \ might_sleep_if((__sleep_us) != 0); \ + if ((sleep_before_op) && __sleep_us) \ + usleep_range((__sleep_us >> 2) + 1, __sleep_us); \ for (;;) { \ - (val) = op(addr); \ - if (cond) \ + bool __expired = __timeout_us && \ + ktime_compare(ktime_get(), __timeout) > 0; \ + /* guarantee 'op' and 'cond' are evaluated after timeout expired */ \ + barrier(); \ + op; \ + if (cond) { \ + ___ret = 0; \ break; \ - if (__timeout_us && \ - ktime_compare(ktime_get(), __timeout) > 0) { \ - (val) = op(addr); \ + } \ + if (__expired) { \ + ___ret = -ETIMEDOUT; \ break; \ } \ if (__sleep_us) \ usleep_range((__sleep_us >> 2) + 1, __sleep_us); \ + cpu_relax(); \ } \ - (cond) ? 0 : -ETIMEDOUT; \ + ___ret; \ }) /** - * 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.txt). + * poll_timeout_us_atomic - Periodically poll and perform an operation until + * a condition is met or a timeout occurs + * + * @op: Operation + * @cond: Break condition + * @delay_us: Time to udelay between operations in us (0 tight-loops). + * Please read udelay() function description for details and + * limitations. * @timeout_us: Timeout in us, 0 means never timeout + * @delay_before_op: if it is true, delay @delay_us before operation. * - * Returns 0 on success and -ETIMEDOUT upon a timeout. In either - * case, the last read value at @addr 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. + * + * Returns: 0 on success and -ETIMEDOUT upon a timeout. */ -#define readx_poll_timeout_atomic(op, addr, val, cond, delay_us, timeout_us) \ +#define poll_timeout_us_atomic(op, cond, delay_us, timeout_us, \ + delay_before_op) \ ({ \ u64 __timeout_us = (timeout_us); \ + s64 __left_ns = __timeout_us * NSEC_PER_USEC; \ unsigned long __delay_us = (delay_us); \ - ktime_t __timeout = ktime_add_us(ktime_get(), __timeout_us); \ + u64 __delay_ns = __delay_us * NSEC_PER_USEC; \ + int ___ret; \ + if ((delay_before_op) && __delay_us) { \ + udelay(__delay_us); \ + if (__timeout_us) \ + __left_ns -= __delay_ns; \ + } \ for (;;) { \ - (val) = op(addr); \ - if (cond) \ + bool __expired = __timeout_us && __left_ns < 0; \ + /* guarantee 'op' and 'cond' are evaluated after timeout expired */ \ + barrier(); \ + op; \ + if (cond) { \ + ___ret = 0; \ break; \ - if (__timeout_us && \ - ktime_compare(ktime_get(), __timeout) > 0) { \ - (val) = op(addr); \ + } \ + if (__expired) { \ + ___ret = -ETIMEDOUT; \ break; \ } \ - if (__delay_us) \ - udelay(__delay_us); \ + if (__delay_us) { \ + udelay(__delay_us); \ + if (__timeout_us) \ + __left_ns -= __delay_ns; \ + } \ + cpu_relax(); \ + if (__timeout_us) \ + __left_ns--; \ } \ - (cond) ? 0 : -ETIMEDOUT; \ + ___ret; \ }) +/** + * 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). Please + * read usleep_range() function description for details and + * limitations. + * @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 + * + * When available, you'll probably want to use one of the specialized + * macros defined below rather than this macro directly. + * + * 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. + */ +#define read_poll_timeout(op, val, cond, sleep_us, timeout_us, \ + sleep_before_read, args...) \ + poll_timeout_us((val) = op(args), cond, sleep_us, timeout_us, sleep_before_read) + +/** + * 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). Please + * read udelay() function description for details and + * limitations. + * @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 + * + * 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. + * + * Returns: 0 on success and -ETIMEDOUT upon a timeout. In either + * case, the last read value at @args is stored in @val. + */ +#define read_poll_timeout_atomic(op, val, cond, sleep_us, timeout_us, \ + sleep_before_read, args...) \ + poll_timeout_us_atomic((val) = op(args), cond, sleep_us, timeout_us, sleep_before_read) + +/** + * 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). Please + * read usleep_range() function description for details and + * limitations. + * @timeout_us: Timeout in us, 0 means never timeout + * + * When available, you'll probably want to use one of the specialized + * macros defined below rather than this macro directly. + * + * 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. + */ +#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). Please + * read udelay() function description for details and + * limitations. + * @timeout_us: Timeout in us, 0 means never timeout + * + * When available, you'll probably want to use one of the specialized + * macros defined below rather than this macro directly. + * + * Returns: 0 on success and -ETIMEDOUT upon a timeout. In either + * case, the last read value at @addr is stored in @val. + */ +#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) |