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 * readx_poll_timeout - Periodically poll an address until a condition is met or a timeout occurs 18 * @op: accessor function (takes @addr as its only argument) 19 * @addr: Address to poll 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 * 27 * Returns 0 on success and -ETIMEDOUT upon a timeout. In either 28 * case, the last read value at @addr is stored in @val. Must not 29 * be called from atomic context if sleep_us or timeout_us are used. 30 * 31 * When available, you'll probably want to use one of the specialized 32 * macros defined below rather than this macro directly. 33 */ 34 #define readx_poll_timeout(op, addr, val, cond, sleep_us, timeout_us) \ 35 ({ \ 36 u64 __timeout_us = (timeout_us); \ 37 unsigned long __sleep_us = (sleep_us); \ 38 ktime_t __timeout = ktime_add_us(ktime_get(), __timeout_us); \ 39 might_sleep_if((__sleep_us) != 0); \ 40 for (;;) { \ 41 (val) = op(addr); \ 42 if (cond) \ 43 break; \ 44 if (__timeout_us && \ 45 ktime_compare(ktime_get(), __timeout) > 0) { \ 46 (val) = op(addr); \ 47 break; \ 48 } \ 49 if (__sleep_us) \ 50 usleep_range((__sleep_us >> 2) + 1, __sleep_us); \ 51 } \ 52 (cond) ? 0 : -ETIMEDOUT; \ 53 }) 54 55 /** 56 * readx_poll_timeout_atomic - Periodically poll an address until a condition is met or a timeout occurs 57 * @op: accessor function (takes @addr as its only argument) 58 * @addr: Address to poll 59 * @val: Variable to read the value into 60 * @cond: Break condition (usually involving @val) 61 * @delay_us: Time to udelay between reads in us (0 tight-loops). Should 62 * be less than ~10us since udelay is used (see 63 * Documentation/timers/timers-howto.rst). 64 * @timeout_us: Timeout in us, 0 means never timeout 65 * 66 * Returns 0 on success and -ETIMEDOUT upon a timeout. In either 67 * case, the last read value at @addr is stored in @val. 68 * 69 * When available, you'll probably want to use one of the specialized 70 * macros defined below rather than this macro directly. 71 */ 72 #define readx_poll_timeout_atomic(op, addr, val, cond, delay_us, timeout_us) \ 73 ({ \ 74 u64 __timeout_us = (timeout_us); \ 75 unsigned long __delay_us = (delay_us); \ 76 ktime_t __timeout = ktime_add_us(ktime_get(), __timeout_us); \ 77 for (;;) { \ 78 (val) = op(addr); \ 79 if (cond) \ 80 break; \ 81 if (__timeout_us && \ 82 ktime_compare(ktime_get(), __timeout) > 0) { \ 83 (val) = op(addr); \ 84 break; \ 85 } \ 86 if (__delay_us) \ 87 udelay(__delay_us); \ 88 } \ 89 (cond) ? 0 : -ETIMEDOUT; \ 90 }) 91 92 93 #define readb_poll_timeout(addr, val, cond, delay_us, timeout_us) \ 94 readx_poll_timeout(readb, addr, val, cond, delay_us, timeout_us) 95 96 #define readb_poll_timeout_atomic(addr, val, cond, delay_us, timeout_us) \ 97 readx_poll_timeout_atomic(readb, addr, val, cond, delay_us, timeout_us) 98 99 #define readw_poll_timeout(addr, val, cond, delay_us, timeout_us) \ 100 readx_poll_timeout(readw, addr, val, cond, delay_us, timeout_us) 101 102 #define readw_poll_timeout_atomic(addr, val, cond, delay_us, timeout_us) \ 103 readx_poll_timeout_atomic(readw, addr, val, cond, delay_us, timeout_us) 104 105 #define readl_poll_timeout(addr, val, cond, delay_us, timeout_us) \ 106 readx_poll_timeout(readl, addr, val, cond, delay_us, timeout_us) 107 108 #define readl_poll_timeout_atomic(addr, val, cond, delay_us, timeout_us) \ 109 readx_poll_timeout_atomic(readl, addr, val, cond, delay_us, timeout_us) 110 111 #define readq_poll_timeout(addr, val, cond, delay_us, timeout_us) \ 112 readx_poll_timeout(readq, addr, val, cond, delay_us, timeout_us) 113 114 #define readq_poll_timeout_atomic(addr, val, cond, delay_us, timeout_us) \ 115 readx_poll_timeout_atomic(readq, addr, val, cond, delay_us, timeout_us) 116 117 #define readb_relaxed_poll_timeout(addr, val, cond, delay_us, timeout_us) \ 118 readx_poll_timeout(readb_relaxed, addr, val, cond, delay_us, timeout_us) 119 120 #define readb_relaxed_poll_timeout_atomic(addr, val, cond, delay_us, timeout_us) \ 121 readx_poll_timeout_atomic(readb_relaxed, addr, val, cond, delay_us, timeout_us) 122 123 #define readw_relaxed_poll_timeout(addr, val, cond, delay_us, timeout_us) \ 124 readx_poll_timeout(readw_relaxed, addr, val, cond, delay_us, timeout_us) 125 126 #define readw_relaxed_poll_timeout_atomic(addr, val, cond, delay_us, timeout_us) \ 127 readx_poll_timeout_atomic(readw_relaxed, addr, val, cond, delay_us, timeout_us) 128 129 #define readl_relaxed_poll_timeout(addr, val, cond, delay_us, timeout_us) \ 130 readx_poll_timeout(readl_relaxed, addr, val, cond, delay_us, timeout_us) 131 132 #define readl_relaxed_poll_timeout_atomic(addr, val, cond, delay_us, timeout_us) \ 133 readx_poll_timeout_atomic(readl_relaxed, addr, val, cond, delay_us, timeout_us) 134 135 #define readq_relaxed_poll_timeout(addr, val, cond, delay_us, timeout_us) \ 136 readx_poll_timeout(readq_relaxed, addr, val, cond, delay_us, timeout_us) 137 138 #define readq_relaxed_poll_timeout_atomic(addr, val, cond, delay_us, timeout_us) \ 139 readx_poll_timeout_atomic(readq_relaxed, addr, val, cond, delay_us, timeout_us) 140 141 #endif /* _LINUX_IOPOLL_H */ 142
