1 /* 2 * Copyright (c) 2012-2014 The Linux Foundation. All rights reserved. 3 * 4 * This program is free software; you can redistribute it and/or modify 5 * it under the terms of the GNU General Public License version 2 and 6 * only version 2 as published by the Free Software Foundation. 7 * 8 * This program is distributed in the hope that it will be useful, 9 * but WITHOUT ANY WARRANTY; without even the implied warranty of 10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 11 * GNU General Public License for more details. 12 * 13 */ 14 15 #ifndef _LINUX_IOPOLL_H 16 #define _LINUX_IOPOLL_H 17 18 #include <linux/kernel.h> 19 #include <linux/types.h> 20 #include <linux/hrtimer.h> 21 #include <linux/delay.h> 22 #include <linux/errno.h> 23 #include <linux/io.h> 24 25 /** 26 * readx_poll_timeout - Periodically poll an address until a condition is met or a timeout occurs 27 * @op: accessor function (takes @addr as its only argument) 28 * @addr: Address to poll 29 * @val: Variable to read the value into 30 * @cond: Break condition (usually involving @val) 31 * @sleep_us: Maximum time to sleep between reads in us (0 32 * tight-loops). Should be less than ~20ms since usleep_range 33 * is used (see Documentation/timers/timers-howto.txt). 34 * @timeout_us: Timeout in us, 0 means never timeout 35 * 36 * Returns 0 on success and -ETIMEDOUT upon a timeout. In either 37 * case, the last read value at @addr is stored in @val. Must not 38 * be called from atomic context if sleep_us or timeout_us are used. 39 * 40 * When available, you'll probably want to use one of the specialized 41 * macros defined below rather than this macro directly. 42 */ 43 #define readx_poll_timeout(op, addr, val, cond, sleep_us, timeout_us) \ 44 ({ \ 45 ktime_t timeout = ktime_add_us(ktime_get(), timeout_us); \ 46 might_sleep_if(sleep_us); \ 47 for (;;) { \ 48 (val) = op(addr); \ 49 if (cond) \ 50 break; \ 51 if (timeout_us && ktime_compare(ktime_get(), timeout) > 0) { \ 52 (val) = op(addr); \ 53 break; \ 54 } \ 55 if (sleep_us) \ 56 usleep_range((sleep_us >> 2) + 1, sleep_us); \ 57 } \ 58 (cond) ? 0 : -ETIMEDOUT; \ 59 }) 60 61 /** 62 * readx_poll_timeout_atomic - Periodically poll an address until a condition is met or a timeout occurs 63 * @op: accessor function (takes @addr as its only argument) 64 * @addr: Address to poll 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.txt). 70 * @timeout_us: Timeout in us, 0 means never timeout 71 * 72 * Returns 0 on success and -ETIMEDOUT upon a timeout. In either 73 * case, the last read value at @addr is stored in @val. 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_atomic(op, addr, val, cond, delay_us, timeout_us) \ 79 ({ \ 80 ktime_t timeout = ktime_add_us(ktime_get(), timeout_us); \ 81 for (;;) { \ 82 (val) = op(addr); \ 83 if (cond) \ 84 break; \ 85 if (timeout_us && ktime_compare(ktime_get(), timeout) > 0) { \ 86 (val) = op(addr); \ 87 break; \ 88 } \ 89 if (delay_us) \ 90 udelay(delay_us); \ 91 } \ 92 (cond) ? 0 : -ETIMEDOUT; \ 93 }) 94 95 96 #define readb_poll_timeout(addr, val, cond, delay_us, timeout_us) \ 97 readx_poll_timeout(readb, addr, val, cond, delay_us, timeout_us) 98 99 #define readb_poll_timeout_atomic(addr, val, cond, delay_us, timeout_us) \ 100 readx_poll_timeout_atomic(readb, addr, val, cond, delay_us, timeout_us) 101 102 #define readw_poll_timeout(addr, val, cond, delay_us, timeout_us) \ 103 readx_poll_timeout(readw, addr, val, cond, delay_us, timeout_us) 104 105 #define readw_poll_timeout_atomic(addr, val, cond, delay_us, timeout_us) \ 106 readx_poll_timeout_atomic(readw, addr, val, cond, delay_us, timeout_us) 107 108 #define readl_poll_timeout(addr, val, cond, delay_us, timeout_us) \ 109 readx_poll_timeout(readl, addr, val, cond, delay_us, timeout_us) 110 111 #define readl_poll_timeout_atomic(addr, val, cond, delay_us, timeout_us) \ 112 readx_poll_timeout_atomic(readl, addr, val, cond, delay_us, timeout_us) 113 114 #define readq_poll_timeout(addr, val, cond, delay_us, timeout_us) \ 115 readx_poll_timeout(readq, addr, val, cond, delay_us, timeout_us) 116 117 #define readq_poll_timeout_atomic(addr, val, cond, delay_us, timeout_us) \ 118 readx_poll_timeout_atomic(readq, addr, val, cond, delay_us, timeout_us) 119 120 #define readb_relaxed_poll_timeout(addr, val, cond, delay_us, timeout_us) \ 121 readx_poll_timeout(readb_relaxed, addr, val, cond, delay_us, timeout_us) 122 123 #define readb_relaxed_poll_timeout_atomic(addr, val, cond, delay_us, timeout_us) \ 124 readx_poll_timeout_atomic(readb_relaxed, addr, val, cond, delay_us, timeout_us) 125 126 #define readw_relaxed_poll_timeout(addr, val, cond, delay_us, timeout_us) \ 127 readx_poll_timeout(readw_relaxed, addr, val, cond, delay_us, timeout_us) 128 129 #define readw_relaxed_poll_timeout_atomic(addr, val, cond, delay_us, timeout_us) \ 130 readx_poll_timeout_atomic(readw_relaxed, addr, val, cond, delay_us, timeout_us) 131 132 #define readl_relaxed_poll_timeout(addr, val, cond, delay_us, timeout_us) \ 133 readx_poll_timeout(readl_relaxed, addr, val, cond, delay_us, timeout_us) 134 135 #define readl_relaxed_poll_timeout_atomic(addr, val, cond, delay_us, timeout_us) \ 136 readx_poll_timeout_atomic(readl_relaxed, addr, val, cond, delay_us, timeout_us) 137 138 #define readq_relaxed_poll_timeout(addr, val, cond, delay_us, timeout_us) \ 139 readx_poll_timeout(readq_relaxed, addr, val, cond, delay_us, timeout_us) 140 141 #define readq_relaxed_poll_timeout_atomic(addr, val, cond, delay_us, timeout_us) \ 142 readx_poll_timeout_atomic(readq_relaxed, addr, val, cond, delay_us, timeout_us) 143 144 #endif /* _LINUX_IOPOLL_H */ 145