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 <watchdog.h> 15 #include <linux/errno.h> 16 #include <asm/io.h> 17 18 /** 19 * wait_for_bit() waits for bit set/cleared in register 20 * 21 * Function polls register waiting for specific bit(s) change 22 * (either 0->1 or 1->0). It can fail under two conditions: 23 * - Timeout 24 * - User interaction (CTRL-C) 25 * Function succeeds only if all bits of masked register are set/cleared 26 * (depending on set option). 27 * 28 * @param prefix Prefix added to timeout messagge (message visible only 29 * with debug enabled) 30 * @param reg Register that will be read (using readl()) 31 * @param mask Bit(s) of register that must be active 32 * @param set Selects wait condition (bit set or clear) 33 * @param timeout_ms Timeout (in miliseconds) 34 * @param breakable Enables CTRL-C interruption 35 * @return 0 on success, -ETIMEDOUT or -EINTR on failure 36 */ 37 static inline int wait_for_bit(const char *prefix, const u32 *reg, 38 const u32 mask, const bool set, 39 const unsigned int timeout_ms, 40 const bool breakable) 41 { 42 u32 val; 43 unsigned long start = get_timer(0); 44 45 while (1) { 46 val = readl(reg); 47 48 if (!set) 49 val = ~val; 50 51 if ((val & mask) == mask) 52 return 0; 53 54 if (get_timer(start) > timeout_ms) 55 break; 56 57 if (breakable && ctrlc()) { 58 puts("Abort\n"); 59 return -EINTR; 60 } 61 62 udelay(1); 63 WATCHDOG_RESET(); 64 } 65 66 debug("%s: Timeout (reg=%p mask=%08x wait_set=%i)\n", prefix, reg, mask, 67 set); 68 69 return -ETIMEDOUT; 70 } 71 72 73 #endif 74