1 /* SPDX-License-Identifier: GPL-2.0-only */ 2 /* 3 * Copyright (c) 2012-2014 The Linux Foundation. All rights reserved. 4 */ 5 6 #ifndef _LINUX_IOPOLL_H 7 #define _LINUX_IOPOLL_H 8 9 #include <linux/kernel.h> 10 #include <linux/types.h> 11 #include <linux/ktime.h> 12 #include <linux/delay.h> 13 #include <linux/errno.h> 14 #include <linux/io.h> 15 16 /** 17 * read_poll_timeout - Periodically poll an address until a condition is 18 * met or a timeout occurs 19 * @op: accessor function (takes @args as its arguments) 20 * @val: Variable to read the value into 21 * @cond: Break condition (usually involving @val) 22 * @sleep_us: Maximum time to sleep between reads in us (0 23 * tight-loops). Should be less than ~20ms since usleep_range 24 * is used (see Documentation/timers/timers-howto.rst). 25 * @timeout_us: Timeout in us, 0 means never timeout 26 * @sleep_before_read: if it is true, sleep @sleep_us before read. 27 * @args: arguments for @op poll 28 * 29 * Returns 0 on success and -ETIMEDOUT upon a timeout. In either 30 * case, the last read value at @args is stored in @val. Must not 31 * be called from atomic context if sleep_us or timeout_us are used. 32 * 33 * When available, you'll probably want to use one of the specialized 34 * macros defined below rather than this macro directly. 35 */ 36 #define read_poll_timeout(op, val, cond, sleep_us, timeout_us, \ 37 sleep_before_read, args...) \ 38 ({ \ 39 u64 __timeout_us = (timeout_us); \ 40 unsigned long __sleep_us = (sleep_us); \ 41 ktime_t __timeout = ktime_add_us(ktime_get(), __timeout_us); \ 42 might_sleep_if((__sleep_us) != 0); \ 43 if (sleep_before_read && __sleep_us) \ 44 usleep_range((__sleep_us >> 2) + 1, __sleep_us); \ 45 for (;;) { \ 46 (val) = op(args); \ 47 if (cond) \ 48 break; \ 49 if (__timeout_us && \ 50 ktime_compare(ktime_get(), __timeout) > 0) { \ 51 (val) = op(args); \ 52 break; \ 53 } \ 54 if (__sleep_us) \ 55 usleep_range((__sleep_us >> 2) + 1, __sleep_us); \ 56 } \ 57 (cond) ? 0 : -ETIMEDOUT; \ 58 }) 59 60 /** 61 * readx_poll_timeout - Periodically poll an address until a condition is met or a timeout occurs 62 * @op: accessor function (takes @addr as its only argument) 63 * @addr: Address to poll 64 * @val: Variable to read the value into 65 * @cond: Break condition (usually involving @val) 66 * @sleep_us: Maximum time to sleep between reads in us (0 67 * tight-loops). Should be less than ~20ms since usleep_range 68 * is used (see Documentation/timers/timers-howto.rst). 69 * @timeout_us: Timeout in us, 0 means never timeout 70 * 71 * Returns 0 on success and -ETIMEDOUT upon a timeout. In either 72 * case, the last read value at @addr is stored in @val. Must not 73 * be called from atomic context if sleep_us or timeout_us are used. 74 * 75 * When available, you'll probably want to use one of the specialized 76 * macros defined below rather than this macro directly. 77 */ 78 #define readx_poll_timeout(op, addr, val, cond, sleep_us, timeout_us) \ 79 read_poll_timeout(op, val, cond, sleep_us, timeout_us, false, addr) 80 81 /** 82 * readx_poll_timeout_atomic - Periodically poll an address until a condition is met or a timeout occurs 83 * @op: accessor function (takes @addr as its only argument) 84 * @addr: Address to poll 85 * @val: Variable to read the value into 86 * @cond: Break condition (usually involving @val) 87 * @delay_us: Time to udelay between reads in us (0 tight-loops). Should 88 * be less than ~10us since udelay is used (see 89 * Documentation/timers/timers-howto.rst). 90 * @timeout_us: Timeout in us, 0 means never timeout 91 * 92 * Returns 0 on success and -ETIMEDOUT upon a timeout. In either 93 * case, the last read value at @addr is stored in @val. 94 * 95 * When available, you'll probably want to use one of the specialized 96 * macros defined below rather than this macro directly. 97 */ 98 #define readx_poll_timeout_atomic(op, addr, val, cond, delay_us, timeout_us) \ 99 ({ \ 100 u64 __timeout_us = (timeout_us); \ 101 unsigned long __delay_us = (delay_us); \ 102 ktime_t __timeout = ktime_add_us(ktime_get(), __timeout_us); \ 103 for (;;) { \ 104 (val) = op(addr); \ 105 if (cond) \ 106 break; \ 107 if (__timeout_us && \ 108 ktime_compare(ktime_get(), __timeout) > 0) { \ 109 (val) = op(addr); \ 110 break; \ 111 } \ 112 if (__delay_us) \ 113 udelay(__delay_us); \ 114 } \ 115 (cond) ? 0 : -ETIMEDOUT; \ 116 }) 117 118 119 #define readb_poll_timeout(addr, val, cond, delay_us, timeout_us) \ 120 readx_poll_timeout(readb, addr, val, cond, delay_us, timeout_us) 121 122 #define readb_poll_timeout_atomic(addr, val, cond, delay_us, timeout_us) \ 123 readx_poll_timeout_atomic(readb, addr, val, cond, delay_us, timeout_us) 124 125 #define readw_poll_timeout(addr, val, cond, delay_us, timeout_us) \ 126 readx_poll_timeout(readw, addr, val, cond, delay_us, timeout_us) 127 128 #define readw_poll_timeout_atomic(addr, val, cond, delay_us, timeout_us) \ 129 readx_poll_timeout_atomic(readw, addr, val, cond, delay_us, timeout_us) 130 131 #define readl_poll_timeout(addr, val, cond, delay_us, timeout_us) \ 132 readx_poll_timeout(readl, addr, val, cond, delay_us, timeout_us) 133 134 #define readl_poll_timeout_atomic(addr, val, cond, delay_us, timeout_us) \ 135 readx_poll_timeout_atomic(readl, addr, val, cond, delay_us, timeout_us) 136 137 #define readq_poll_timeout(addr, val, cond, delay_us, timeout_us) \ 138 readx_poll_timeout(readq, addr, val, cond, delay_us, timeout_us) 139 140 #define readq_poll_timeout_atomic(addr, val, cond, delay_us, timeout_us) \ 141 readx_poll_timeout_atomic(readq, addr, val, cond, delay_us, timeout_us) 142 143 #define readb_relaxed_poll_timeout(addr, val, cond, delay_us, timeout_us) \ 144 readx_poll_timeout(readb_relaxed, addr, val, cond, delay_us, timeout_us) 145 146 #define readb_relaxed_poll_timeout_atomic(addr, val, cond, delay_us, timeout_us) \ 147 readx_poll_timeout_atomic(readb_relaxed, addr, val, cond, delay_us, timeout_us) 148 149 #define readw_relaxed_poll_timeout(addr, val, cond, delay_us, timeout_us) \ 150 readx_poll_timeout(readw_relaxed, addr, val, cond, delay_us, timeout_us) 151 152 #define readw_relaxed_poll_timeout_atomic(addr, val, cond, delay_us, timeout_us) \ 153 readx_poll_timeout_atomic(readw_relaxed, addr, val, cond, delay_us, timeout_us) 154 155 #define readl_relaxed_poll_timeout(addr, val, cond, delay_us, timeout_us) \ 156 readx_poll_timeout(readl_relaxed, addr, val, cond, delay_us, timeout_us) 157 158 #define readl_relaxed_poll_timeout_atomic(addr, val, cond, delay_us, timeout_us) \ 159 readx_poll_timeout_atomic(readl_relaxed, addr, val, cond, delay_us, timeout_us) 160 161 #define readq_relaxed_poll_timeout(addr, val, cond, delay_us, timeout_us) \ 162 readx_poll_timeout(readq_relaxed, addr, val, cond, delay_us, timeout_us) 163 164 #define readq_relaxed_poll_timeout_atomic(addr, val, cond, delay_us, timeout_us) \ 165 readx_poll_timeout_atomic(readq_relaxed, addr, val, cond, delay_us, timeout_us) 166 167 #endif /* _LINUX_IOPOLL_H */ 168