1 /* 2 * Wait for bit with timeout and ctrlc 3 * 4 * (C) Copyright 2015 Mateusz Kulikowski <mateusz.kulikowski@gmail.com> 5 * 6 * SPDX-License-Identifier: GPL-2.0+ 7 */ 8 9 #ifndef __WAIT_BIT_H 10 #define __WAIT_BIT_H 11 12 #include <common.h> 13 #include <console.h> 14 #include <linux/errno.h> 15 #include <asm/io.h> 16 17 /** 18 * wait_for_bit() waits for bit set/cleared in register 19 * 20 * Function polls register waiting for specific bit(s) change 21 * (either 0->1 or 1->0). It can fail under two conditions: 22 * - Timeout 23 * - User interaction (CTRL-C) 24 * Function succeeds only if all bits of masked register are set/cleared 25 * (depending on set option). 26 * 27 * @param prefix Prefix added to timeout messagge (message visible only 28 * with debug enabled) 29 * @param reg Register that will be read (using readl()) 30 * @param mask Bit(s) of register that must be active 31 * @param set Selects wait condition (bit set or clear) 32 * @param timeout_ms Timeout (in miliseconds) 33 * @param breakable Enables CTRL-C interruption 34 * @return 0 on success, -ETIMEDOUT or -EINTR on failure 35 */ 36 static inline int wait_for_bit(const char *prefix, const u32 *reg, 37 const u32 mask, const bool set, 38 const unsigned int timeout_ms, 39 const bool breakable) 40 { 41 u32 val; 42 unsigned long start = get_timer(0); 43 44 while (1) { 45 val = readl(reg); 46 47 if (!set) 48 val = ~val; 49 50 if ((val & mask) == mask) 51 return 0; 52 53 if (get_timer(start) > timeout_ms) 54 break; 55 56 if (breakable && ctrlc()) { 57 puts("Abort\n"); 58 return -EINTR; 59 } 60 61 udelay(1); 62 } 63 64 debug("%s: Timeout (reg=%p mask=%08x wait_set=%i)\n", prefix, reg, mask, 65 set); 66 67 return -ETIMEDOUT; 68 } 69 70 71 #endif 72