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 * This macro does not rely on timekeeping. Hence it is safe to call even when 78 * timekeeping is suspended, at the expense of an underestimation of wall clock 79 * time, which is rather minimal with a non-zero delay_us. 80 * 81 * When available, you'll probably want to use one of the specialized 82 * macros defined below rather than this macro directly. 83 */ 84 #define read_poll_timeout_atomic(op, val, cond, delay_us, timeout_us, \ 85 delay_before_read, args...) \ 86 ({ \ 87 u64 __timeout_us = (timeout_us); \ 88 s64 __left_ns = __timeout_us * NSEC_PER_USEC; \ 89 unsigned long __delay_us = (delay_us); \ 90 u64 __delay_ns = __delay_us * NSEC_PER_USEC; \ 91 if (delay_before_read && __delay_us) { \ 92 udelay(__delay_us); \ 93 if (__timeout_us) \ 94 __left_ns -= __delay_ns; \ 95 } \ 96 for (;;) { \ 97 (val) = op(args); \ 98 if (cond) \ 99 break; \ 100 if (__timeout_us && __left_ns < 0) { \ 101 (val) = op(args); \ 102 break; \ 103 } \ 104 if (__delay_us) { \ 105 udelay(__delay_us); \ 106 if (__timeout_us) \ 107 __left_ns -= __delay_ns; \ 108 } \ 109 cpu_relax(); \ 110 if (__timeout_us) \ 111 __left_ns--; \ 112 } \ 113 (cond) ? 0 : -ETIMEDOUT; \ 114 }) 115 116 /** 117 * readx_poll_timeout - Periodically poll an address until a condition is met or a timeout occurs 118 * @op: accessor function (takes @addr as its only argument) 119 * @addr: Address to poll 120 * @val: Variable to read the value into 121 * @cond: Break condition (usually involving @val) 122 * @sleep_us: Maximum time to sleep between reads in us (0 123 * tight-loops). Should be less than ~20ms since usleep_range 124 * is used (see Documentation/timers/timers-howto.rst). 125 * @timeout_us: Timeout in us, 0 means never timeout 126 * 127 * Returns 0 on success and -ETIMEDOUT upon a timeout. In either 128 * case, the last read value at @addr is stored in @val. Must not 129 * be called from atomic context if sleep_us or timeout_us are used. 130 * 131 * When available, you'll probably want to use one of the specialized 132 * macros defined below rather than this macro directly. 133 */ 134 #define readx_poll_timeout(op, addr, val, cond, sleep_us, timeout_us) \ 135 read_poll_timeout(op, val, cond, sleep_us, timeout_us, false, addr) 136 137 /** 138 * readx_poll_timeout_atomic - Periodically poll an address until a condition is met or a timeout occurs 139 * @op: accessor function (takes @addr as its only argument) 140 * @addr: Address to poll 141 * @val: Variable to read the value into 142 * @cond: Break condition (usually involving @val) 143 * @delay_us: Time to udelay between reads in us (0 tight-loops). Should 144 * be less than ~10us since udelay is used (see 145 * Documentation/timers/timers-howto.rst). 146 * @timeout_us: Timeout in us, 0 means never timeout 147 * 148 * Returns 0 on success and -ETIMEDOUT upon a timeout. In either 149 * case, the last read value at @addr is stored in @val. 150 * 151 * When available, you'll probably want to use one of the specialized 152 * macros defined below rather than this macro directly. 153 */ 154 #define readx_poll_timeout_atomic(op, addr, val, cond, delay_us, timeout_us) \ 155 read_poll_timeout_atomic(op, val, cond, delay_us, timeout_us, false, addr) 156 157 #define readb_poll_timeout(addr, val, cond, delay_us, timeout_us) \ 158 readx_poll_timeout(readb, addr, val, cond, delay_us, timeout_us) 159 160 #define readb_poll_timeout_atomic(addr, val, cond, delay_us, timeout_us) \ 161 readx_poll_timeout_atomic(readb, addr, val, cond, delay_us, timeout_us) 162 163 #define readw_poll_timeout(addr, val, cond, delay_us, timeout_us) \ 164 readx_poll_timeout(readw, addr, val, cond, delay_us, timeout_us) 165 166 #define readw_poll_timeout_atomic(addr, val, cond, delay_us, timeout_us) \ 167 readx_poll_timeout_atomic(readw, addr, val, cond, delay_us, timeout_us) 168 169 #define readl_poll_timeout(addr, val, cond, delay_us, timeout_us) \ 170 readx_poll_timeout(readl, addr, val, cond, delay_us, timeout_us) 171 172 #define readl_poll_timeout_atomic(addr, val, cond, delay_us, timeout_us) \ 173 readx_poll_timeout_atomic(readl, addr, val, cond, delay_us, timeout_us) 174 175 #define readq_poll_timeout(addr, val, cond, delay_us, timeout_us) \ 176 readx_poll_timeout(readq, addr, val, cond, delay_us, timeout_us) 177 178 #define readq_poll_timeout_atomic(addr, val, cond, delay_us, timeout_us) \ 179 readx_poll_timeout_atomic(readq, addr, val, cond, delay_us, timeout_us) 180 181 #define readb_relaxed_poll_timeout(addr, val, cond, delay_us, timeout_us) \ 182 readx_poll_timeout(readb_relaxed, addr, val, cond, delay_us, timeout_us) 183 184 #define readb_relaxed_poll_timeout_atomic(addr, val, cond, delay_us, timeout_us) \ 185 readx_poll_timeout_atomic(readb_relaxed, addr, val, cond, delay_us, timeout_us) 186 187 #define readw_relaxed_poll_timeout(addr, val, cond, delay_us, timeout_us) \ 188 readx_poll_timeout(readw_relaxed, addr, val, cond, delay_us, timeout_us) 189 190 #define readw_relaxed_poll_timeout_atomic(addr, val, cond, delay_us, timeout_us) \ 191 readx_poll_timeout_atomic(readw_relaxed, addr, val, cond, delay_us, timeout_us) 192 193 #define readl_relaxed_poll_timeout(addr, val, cond, delay_us, timeout_us) \ 194 readx_poll_timeout(readl_relaxed, addr, val, cond, delay_us, timeout_us) 195 196 #define readl_relaxed_poll_timeout_atomic(addr, val, cond, delay_us, timeout_us) \ 197 readx_poll_timeout_atomic(readl_relaxed, addr, val, cond, delay_us, timeout_us) 198 199 #define readq_relaxed_poll_timeout(addr, val, cond, delay_us, timeout_us) \ 200 readx_poll_timeout(readq_relaxed, addr, val, cond, delay_us, timeout_us) 201 202 #define readq_relaxed_poll_timeout_atomic(addr, val, cond, delay_us, timeout_us) \ 203 readx_poll_timeout_atomic(readq_relaxed, addr, val, cond, delay_us, timeout_us) 204 205 #endif /* _LINUX_IOPOLL_H */ 206