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 * read_poll_timeout_atomic - Periodically poll an address until a condition is 62 * met or a timeout occurs 63 * @op: accessor function (takes @args as its arguments) 64 * @val: Variable to read the value into 65 * @cond: Break condition (usually involving @val) 66 * @delay_us: Time to udelay between reads in us (0 tight-loops). Should 67 * be less than ~10us since udelay is used (see 68 * Documentation/timers/timers-howto.rst). 69 * @timeout_us: Timeout in us, 0 means never timeout 70 * @delay_before_read: if it is true, delay @delay_us before read. 71 * @args: arguments for @op poll 72 * 73 * Returns 0 on success and -ETIMEDOUT upon a timeout. In either 74 * case, the last read value at @args is stored in @val. 75 * 76 * When available, you'll probably want to use one of the specialized 77 * macros defined below rather than this macro directly. 78 */ 79 #define read_poll_timeout_atomic(op, val, cond, delay_us, timeout_us, \ 80 delay_before_read, args...) \ 81 ({ \ 82 u64 __timeout_us = (timeout_us); \ 83 unsigned long __delay_us = (delay_us); \ 84 ktime_t __timeout = ktime_add_us(ktime_get(), __timeout_us); \ 85 if (delay_before_read && __delay_us) \ 86 udelay(__delay_us); \ 87 for (;;) { \ 88 (val) = op(args); \ 89 if (cond) \ 90 break; \ 91 if (__timeout_us && \ 92 ktime_compare(ktime_get(), __timeout) > 0) { \ 93 (val) = op(args); \ 94 break; \ 95 } \ 96 if (__delay_us) \ 97 udelay(__delay_us); \ 98 } \ 99 (cond) ? 0 : -ETIMEDOUT; \ 100 }) 101 102 /** 103 * readx_poll_timeout - Periodically poll an address until a condition is met or a timeout occurs 104 * @op: accessor function (takes @addr as its only argument) 105 * @addr: Address to poll 106 * @val: Variable to read the value into 107 * @cond: Break condition (usually involving @val) 108 * @sleep_us: Maximum time to sleep between reads in us (0 109 * tight-loops). Should be less than ~20ms since usleep_range 110 * is used (see Documentation/timers/timers-howto.rst). 111 * @timeout_us: Timeout in us, 0 means never timeout 112 * 113 * Returns 0 on success and -ETIMEDOUT upon a timeout. In either 114 * case, the last read value at @addr is stored in @val. Must not 115 * be called from atomic context if sleep_us or timeout_us are used. 116 * 117 * When available, you'll probably want to use one of the specialized 118 * macros defined below rather than this macro directly. 119 */ 120 #define readx_poll_timeout(op, addr, val, cond, sleep_us, timeout_us) \ 121 read_poll_timeout(op, val, cond, sleep_us, timeout_us, false, addr) 122 123 /** 124 * readx_poll_timeout_atomic - Periodically poll an address until a condition is met or a timeout occurs 125 * @op: accessor function (takes @addr as its only argument) 126 * @addr: Address to poll 127 * @val: Variable to read the value into 128 * @cond: Break condition (usually involving @val) 129 * @delay_us: Time to udelay between reads in us (0 tight-loops). Should 130 * be less than ~10us since udelay is used (see 131 * Documentation/timers/timers-howto.rst). 132 * @timeout_us: Timeout in us, 0 means never timeout 133 * 134 * Returns 0 on success and -ETIMEDOUT upon a timeout. In either 135 * case, the last read value at @addr is stored in @val. 136 * 137 * When available, you'll probably want to use one of the specialized 138 * macros defined below rather than this macro directly. 139 */ 140 #define readx_poll_timeout_atomic(op, addr, val, cond, delay_us, timeout_us) \ 141 read_poll_timeout_atomic(op, val, cond, delay_us, timeout_us, false, addr) 142 143 #define readb_poll_timeout(addr, val, cond, delay_us, timeout_us) \ 144 readx_poll_timeout(readb, addr, val, cond, delay_us, timeout_us) 145 146 #define readb_poll_timeout_atomic(addr, val, cond, delay_us, timeout_us) \ 147 readx_poll_timeout_atomic(readb, addr, val, cond, delay_us, timeout_us) 148 149 #define readw_poll_timeout(addr, val, cond, delay_us, timeout_us) \ 150 readx_poll_timeout(readw, addr, val, cond, delay_us, timeout_us) 151 152 #define readw_poll_timeout_atomic(addr, val, cond, delay_us, timeout_us) \ 153 readx_poll_timeout_atomic(readw, addr, val, cond, delay_us, timeout_us) 154 155 #define readl_poll_timeout(addr, val, cond, delay_us, timeout_us) \ 156 readx_poll_timeout(readl, addr, val, cond, delay_us, timeout_us) 157 158 #define readl_poll_timeout_atomic(addr, val, cond, delay_us, timeout_us) \ 159 readx_poll_timeout_atomic(readl, addr, val, cond, delay_us, timeout_us) 160 161 #define readq_poll_timeout(addr, val, cond, delay_us, timeout_us) \ 162 readx_poll_timeout(readq, addr, val, cond, delay_us, timeout_us) 163 164 #define readq_poll_timeout_atomic(addr, val, cond, delay_us, timeout_us) \ 165 readx_poll_timeout_atomic(readq, addr, val, cond, delay_us, timeout_us) 166 167 #define readb_relaxed_poll_timeout(addr, val, cond, delay_us, timeout_us) \ 168 readx_poll_timeout(readb_relaxed, addr, val, cond, delay_us, timeout_us) 169 170 #define readb_relaxed_poll_timeout_atomic(addr, val, cond, delay_us, timeout_us) \ 171 readx_poll_timeout_atomic(readb_relaxed, addr, val, cond, delay_us, timeout_us) 172 173 #define readw_relaxed_poll_timeout(addr, val, cond, delay_us, timeout_us) \ 174 readx_poll_timeout(readw_relaxed, addr, val, cond, delay_us, timeout_us) 175 176 #define readw_relaxed_poll_timeout_atomic(addr, val, cond, delay_us, timeout_us) \ 177 readx_poll_timeout_atomic(readw_relaxed, addr, val, cond, delay_us, timeout_us) 178 179 #define readl_relaxed_poll_timeout(addr, val, cond, delay_us, timeout_us) \ 180 readx_poll_timeout(readl_relaxed, addr, val, cond, delay_us, timeout_us) 181 182 #define readl_relaxed_poll_timeout_atomic(addr, val, cond, delay_us, timeout_us) \ 183 readx_poll_timeout_atomic(readl_relaxed, addr, val, cond, delay_us, timeout_us) 184 185 #define readq_relaxed_poll_timeout(addr, val, cond, delay_us, timeout_us) \ 186 readx_poll_timeout(readq_relaxed, addr, val, cond, delay_us, timeout_us) 187 188 #define readq_relaxed_poll_timeout_atomic(addr, val, cond, delay_us, timeout_us) \ 189 readx_poll_timeout_atomic(readq_relaxed, addr, val, cond, delay_us, timeout_us) 190 191 #endif /* _LINUX_IOPOLL_H */ 192