1 /* 2 * Copyright (c) 2015-2024, Arm Limited and Contributors. All rights reserved. 3 * 4 * SPDX-License-Identifier: BSD-3-Clause 5 */ 6 7 #include <assert.h> 8 9 #include <platform_def.h> 10 11 #include <drivers/delay_timer.h> 12 #include <lib/utils_def.h> 13 14 /*********************************************************** 15 * The delay timer implementation 16 ***********************************************************/ 17 static const timer_ops_t *timer_ops; 18 19 /*********************************************************** 20 * Delay for the given number of microseconds. The driver must 21 * be initialized before calling this function. 22 ***********************************************************/ udelay(uint32_t usec)23void udelay(uint32_t usec) 24 { 25 assert((timer_ops != NULL) && 26 (timer_ops->clk_mult != 0U) && 27 (timer_ops->clk_div != 0U) && 28 (timer_ops->get_timer_value != NULL)); 29 30 uint32_t start, delta; 31 uint64_t total_delta; 32 33 assert(usec < (UINT64_MAX / timer_ops->clk_div)); 34 35 start = timer_ops->get_timer_value(); 36 37 /* Add an extra tick to avoid delaying less than requested. */ 38 total_delta = 39 div_round_up((uint64_t)usec * timer_ops->clk_div, 40 timer_ops->clk_mult) + 1U; 41 /* 42 * Precaution for the total_delta ~ UINT32_MAX and the fact that we 43 * cannot catch every tick of the timer. 44 * For example 100MHz timer over 25MHz APB will miss at least 4 ticks. 45 * 1000U is an arbitrary big number which is believed to be sufficient. 46 */ 47 assert(total_delta < (UINT32_MAX - 1000U)); 48 49 do { 50 /* 51 * If the timer value wraps around, the subtraction will 52 * overflow and it will still give the correct result. 53 * delta is decreasing counter 54 */ 55 delta = start - timer_ops->get_timer_value(); 56 57 } while (delta < total_delta); 58 } 59 60 /*********************************************************** 61 * Delay for the given number of milliseconds. The driver must 62 * be initialized before calling this function. 63 ***********************************************************/ mdelay(uint32_t msec)64void mdelay(uint32_t msec) 65 { 66 assert((msec * 1000UL) < UINT32_MAX); 67 udelay(msec * 1000U); 68 } 69 70 /*********************************************************** 71 * Initialize the timer. The fields in the provided timer 72 * ops pointer must be valid. 73 ***********************************************************/ timer_init(const timer_ops_t * ops_ptr)74void timer_init(const timer_ops_t *ops_ptr) 75 { 76 assert((ops_ptr != NULL) && 77 (ops_ptr->clk_mult != 0U) && 78 (ops_ptr->clk_div != 0U) && 79 (ops_ptr->get_timer_value != NULL)); 80 81 timer_ops = ops_ptr; 82 } 83 84 /*********************************************************** 85 * Initialize the timer in us 86 ***********************************************************/ timeout_init_us(uint32_t usec)87uint64_t timeout_init_us(uint32_t usec) 88 { 89 assert(timer_ops != NULL); 90 assert(timer_ops->timeout_init_us != NULL); 91 92 return timer_ops->timeout_init_us(usec); 93 } 94 95 /*********************************************************** 96 * check the given timeout elapsed or not. 97 ***********************************************************/ timeout_elapsed(uint64_t cnt)98bool timeout_elapsed(uint64_t cnt) 99 { 100 assert(timer_ops != NULL); 101 assert(timer_ops->timeout_elapsed != NULL); 102 103 return timer_ops->timeout_elapsed(cnt); 104 } 105