1 /* 2 * Copyright (c) 2015-2018, 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 ***********************************************************/ 23 void 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, total_delta; 31 32 assert(usec < (UINT32_MAX / timer_ops->clk_div)); 33 34 start = timer_ops->get_timer_value(); 35 36 /* Add an extra tick to avoid delaying less than requested. */ 37 total_delta = 38 div_round_up(usec * timer_ops->clk_div, 39 timer_ops->clk_mult) + 1U; 40 41 do { 42 /* 43 * If the timer value wraps around, the subtraction will 44 * overflow and it will still give the correct result. 45 */ 46 delta = start - timer_ops->get_timer_value(); /* Decreasing counter */ 47 48 } while (delta < total_delta); 49 } 50 51 /*********************************************************** 52 * Delay for the given number of milliseconds. The driver must 53 * be initialized before calling this function. 54 ***********************************************************/ 55 void mdelay(uint32_t msec) 56 { 57 udelay(msec * 1000U); 58 } 59 60 /*********************************************************** 61 * Initialize the timer. The fields in the provided timer 62 * ops pointer must be valid. 63 ***********************************************************/ 64 void timer_init(const timer_ops_t *ops_ptr) 65 { 66 assert((ops_ptr != NULL) && 67 (ops_ptr->clk_mult != 0U) && 68 (ops_ptr->clk_div != 0U) && 69 (ops_ptr->get_timer_value != NULL)); 70 71 timer_ops = ops_ptr; 72 } 73