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 cpu_relax(); \ 57 } \ 58 (cond) ? 0 : -ETIMEDOUT; \ 59 }) 60 61 /** 62 * read_poll_timeout_atomic - Periodically poll an address until a condition is 63 * met or a timeout occurs 64 * @op: accessor function (takes @args as its arguments) 65 * @val: Variable to read the value into 66 * @cond: Break condition (usually involving @val) 67 * @delay_us: Time to udelay between reads in us (0 tight-loops). Should 68 * be less than ~10us since udelay is used (see 69 * Documentation/timers/timers-howto.rst). 70 * @timeout_us: Timeout in us, 0 means never timeout 71 * @delay_before_read: if it is true, delay @delay_us before read. 72 * @args: arguments for @op poll 73 * 74 * Returns 0 on success and -ETIMEDOUT upon a timeout. In either 75 * case, the last read value at @args is stored in @val. 76 * 77 * When available, you'll probably want to use one of the specialized 78 * macros defined below rather than this macro directly. 79 */ 80 #define read_poll_timeout_atomic(op, val, cond, delay_us, timeout_us, \ 81 delay_before_read, args...) \ 82 ({ \ 83 u64 __timeout_us = (timeout_us); \ 84 unsigned long __delay_us = (delay_us); \ 85 ktime_t __timeout = ktime_add_us(ktime_get(), __timeout_us); \ 86 if (delay_before_read && __delay_us) \ 87 udelay(__delay_us); \ 88 for (;;) { \ 89 (val) = op(args); \ 90 if (cond) \ 91 break; \ 92 if (__timeout_us && \ 93 ktime_compare(ktime_get(), __timeout) > 0) { \ 94 (val) = op(args); \ 95 break; \ 96 } \ 97 if (__delay_us) \ 98 udelay(__delay_us); \ 99 cpu_relax(); \ 100 } \ 101 (cond) ? 0 : -ETIMEDOUT; \ 102 }) 103 104 /** 105 * readx_poll_timeout - Periodically poll an address until a condition is met or a timeout occurs 106 * @op: accessor function (takes @addr as its only argument) 107 * @addr: Address to poll 108 * @val: Variable to read the value into 109 * @cond: Break condition (usually involving @val) 110 * @sleep_us: Maximum time to sleep between reads in us (0 111 * tight-loops). Should be less than ~20ms since usleep_range 112 * is used (see Documentation/timers/timers-howto.rst). 113 * @timeout_us: Timeout in us, 0 means never timeout 114 * 115 * Returns 0 on success and -ETIMEDOUT upon a timeout. In either 116 * case, the last read value at @addr is stored in @val. Must not 117 * be called from atomic context if sleep_us or timeout_us are used. 118 * 119 * When available, you'll probably want to use one of the specialized 120 * macros defined below rather than this macro directly. 121 */ 122 #define readx_poll_timeout(op, addr, val, cond, sleep_us, timeout_us) \ 123 read_poll_timeout(op, val, cond, sleep_us, timeout_us, false, addr) 124 125 /** 126 * readx_poll_timeout_atomic - Periodically poll an address until a condition is met or a timeout occurs 127 * @op: accessor function (takes @addr as its only argument) 128 * @addr: Address to poll 129 * @val: Variable to read the value into 130 * @cond: Break condition (usually involving @val) 131 * @delay_us: Time to udelay between reads in us (0 tight-loops). Should 132 * be less than ~10us since udelay is used (see 133 * Documentation/timers/timers-howto.rst). 134 * @timeout_us: Timeout in us, 0 means never timeout 135 * 136 * Returns 0 on success and -ETIMEDOUT upon a timeout. In either 137 * case, the last read value at @addr is stored in @val. 138 * 139 * When available, you'll probably want to use one of the specialized 140 * macros defined below rather than this macro directly. 141 */ 142 #define readx_poll_timeout_atomic(op, addr, val, cond, delay_us, timeout_us) \ 143 read_poll_timeout_atomic(op, val, cond, delay_us, timeout_us, false, addr) 144 145 #define readb_poll_timeout(addr, val, cond, delay_us, timeout_us) \ 146 readx_poll_timeout(readb, addr, val, cond, delay_us, timeout_us) 147 148 #define readb_poll_timeout_atomic(addr, val, cond, delay_us, timeout_us) \ 149 readx_poll_timeout_atomic(readb, addr, val, cond, delay_us, timeout_us) 150 151 #define readw_poll_timeout(addr, val, cond, delay_us, timeout_us) \ 152 readx_poll_timeout(readw, addr, val, cond, delay_us, timeout_us) 153 154 #define readw_poll_timeout_atomic(addr, val, cond, delay_us, timeout_us) \ 155 readx_poll_timeout_atomic(readw, addr, val, cond, delay_us, timeout_us) 156 157 #define readl_poll_timeout(addr, val, cond, delay_us, timeout_us) \ 158 readx_poll_timeout(readl, addr, val, cond, delay_us, timeout_us) 159 160 #define readl_poll_timeout_atomic(addr, val, cond, delay_us, timeout_us) \ 161 readx_poll_timeout_atomic(readl, addr, val, cond, delay_us, timeout_us) 162 163 #define readq_poll_timeout(addr, val, cond, delay_us, timeout_us) \ 164 readx_poll_timeout(readq, addr, val, cond, delay_us, timeout_us) 165 166 #define readq_poll_timeout_atomic(addr, val, cond, delay_us, timeout_us) \ 167 readx_poll_timeout_atomic(readq, addr, val, cond, delay_us, timeout_us) 168 169 #define readb_relaxed_poll_timeout(addr, val, cond, delay_us, timeout_us) \ 170 readx_poll_timeout(readb_relaxed, addr, val, cond, delay_us, timeout_us) 171 172 #define readb_relaxed_poll_timeout_atomic(addr, val, cond, delay_us, timeout_us) \ 173 readx_poll_timeout_atomic(readb_relaxed, addr, val, cond, delay_us, timeout_us) 174 175 #define readw_relaxed_poll_timeout(addr, val, cond, delay_us, timeout_us) \ 176 readx_poll_timeout(readw_relaxed, addr, val, cond, delay_us, timeout_us) 177 178 #define readw_relaxed_poll_timeout_atomic(addr, val, cond, delay_us, timeout_us) \ 179 readx_poll_timeout_atomic(readw_relaxed, addr, val, cond, delay_us, timeout_us) 180 181 #define readl_relaxed_poll_timeout(addr, val, cond, delay_us, timeout_us) \ 182 readx_poll_timeout(readl_relaxed, addr, val, cond, delay_us, timeout_us) 183 184 #define readl_relaxed_poll_timeout_atomic(addr, val, cond, delay_us, timeout_us) \ 185 readx_poll_timeout_atomic(readl_relaxed, addr, val, cond, delay_us, timeout_us) 186 187 #define readq_relaxed_poll_timeout(addr, val, cond, delay_us, timeout_us) \ 188 readx_poll_timeout(readq_relaxed, addr, val, cond, delay_us, timeout_us) 189 190 #define readq_relaxed_poll_timeout_atomic(addr, val, cond, delay_us, timeout_us) \ 191 readx_poll_timeout_atomic(readq_relaxed, addr, val, cond, delay_us, timeout_us) 192 193 #endif /* _LINUX_IOPOLL_H */ 194