1 /* 2 * Copyright (c) 2012-2014 The Linux Foundation. All rights reserved. 3 * 4 * SPDX-License-Identifier: GPL-2.0 5 */ 6 7 #ifndef _LINUX_IOPOLL_H 8 #define _LINUX_IOPOLL_H 9 10 #include <linux/errno.h> 11 #include <linux/io.h> 12 #include <time.h> 13 14 /** 15 * readx_poll_timeout - Periodically poll an address until a condition is met or a timeout occurs 16 * @op: accessor function (takes @addr as its only argument) 17 * @addr: Address to poll 18 * @val: Variable to read the value into 19 * @cond: Break condition (usually involving @val) 20 * @timeout_us: Timeout in us, 0 means never timeout 21 * 22 * Returns 0 on success and -ETIMEDOUT upon a timeout. In either 23 * case, the last read value at @addr is stored in @val. 24 * 25 * When available, you'll probably want to use one of the specialized 26 * macros defined below rather than this macro directly. 27 */ 28 #define readx_poll_timeout(op, addr, val, cond, timeout_us) \ 29 ({ \ 30 unsigned long timeout = timer_get_us() + timeout_us; \ 31 for (;;) { \ 32 (val) = op(addr); \ 33 if (cond) \ 34 break; \ 35 if (timeout_us && time_after(timer_get_us(), timeout)) { \ 36 (val) = op(addr); \ 37 break; \ 38 } \ 39 } \ 40 (cond) ? 0 : -ETIMEDOUT; \ 41 }) 42 43 44 #define readb_poll_timeout(addr, val, cond, timeout_us) \ 45 readx_poll_timeout(readb, addr, val, cond, timeout_us) 46 47 #define readw_poll_timeout(addr, val, cond, timeout_us) \ 48 readx_poll_timeout(readw, addr, val, cond, timeout_us) 49 50 #define readl_poll_timeout(addr, val, cond, timeout_us) \ 51 readx_poll_timeout(readl, addr, val, cond, timeout_us) 52 53 #define readq_poll_timeout(addr, val, cond, timeout_us) \ 54 readx_poll_timeout(readq, addr, val, cond, timeout_us) 55 56 #define readb_relaxed_poll_timeout(addr, val, cond, timeout_us) \ 57 readx_poll_timeout(readb_relaxed, addr, val, cond, timeout_us) 58 59 #define readw_relaxed_poll_timeout(addr, val, cond, timeout_us) \ 60 readx_poll_timeout(readw_relaxed, addr, val, cond, timeout_us) 61 62 #define readl_relaxed_poll_timeout(addr, val, cond, timeout_us) \ 63 readx_poll_timeout(readl_relaxed, addr, val, cond, timeout_us) 64 65 #define readq_relaxed_poll_timeout(addr, val, cond, timeout_us) \ 66 readx_poll_timeout(readq_relaxed, addr, val, cond, timeout_us) 67 68 #endif /* _LINUX_IOPOLL_H */ 69