1 /* 2 * Copyright (c) 2016-2024, Arm Limited and Contributors. All rights reserved. 3 * Copyright (c) 2020, NVIDIA Corporation. All rights reserved. 4 * 5 * SPDX-License-Identifier: BSD-3-Clause 6 */ 7 8 #include <assert.h> 9 10 #include <arch_features.h> 11 #include <arch_helpers.h> 12 #include <common/bl_common.h> 13 #include <common/debug.h> 14 #include <drivers/delay_timer.h> 15 #include <drivers/generic_delay_timer.h> 16 #include <lib/utils_def.h> 17 #include <plat/common/platform.h> 18 19 static timer_ops_t ops; 20 timeout_cnt_us2cnt(uint32_t us)21static uint64_t timeout_cnt_us2cnt(uint32_t us) 22 { 23 return ((uint64_t)us * (uint64_t)read_cntfrq_el0()) / 1000000ULL; 24 } 25 generic_delay_timeout_init_us(uint32_t us)26static uint64_t generic_delay_timeout_init_us(uint32_t us) 27 { 28 uint64_t cnt = timeout_cnt_us2cnt(us); 29 30 cnt += read_cntpct_el0(); 31 32 return cnt; 33 } 34 generic_delay_timeout_elapsed(uint64_t expire_cnt)35static bool generic_delay_timeout_elapsed(uint64_t expire_cnt) 36 { 37 return read_cntpct_el0() > expire_cnt; 38 } 39 generic_delay_get_timer_value(void)40static uint32_t generic_delay_get_timer_value(void) 41 { 42 /* 43 * Generic delay timer implementation expects the timer to be a down 44 * counter. We apply bitwise NOT operator to the tick values returned 45 * by read_cntpct_el0() to simulate the down counter. The value is 46 * clipped from 64 to 32 bits. 47 */ 48 return (uint32_t)(~read_cntpct_el0()); 49 } 50 generic_delay_timer_init_args(uint32_t mult,uint32_t div)51void generic_delay_timer_init_args(uint32_t mult, uint32_t div) 52 { 53 ops.get_timer_value = generic_delay_get_timer_value; 54 ops.clk_mult = mult; 55 ops.clk_div = div; 56 ops.timeout_init_us = generic_delay_timeout_init_us; 57 ops.timeout_elapsed = generic_delay_timeout_elapsed; 58 59 timer_init(&ops); 60 61 VERBOSE("Generic delay timer configured with mult=%u and div=%u\n", 62 mult, div); 63 } 64 generic_delay_timer_init(void)65void generic_delay_timer_init(void) 66 { 67 assert(is_armv7_gentimer_present()); 68 69 /* Value in ticks */ 70 unsigned int mult = MHZ_TICKS_PER_SEC; 71 72 /* Value in ticks per second (Hz) */ 73 unsigned int div = plat_get_syscnt_freq2(); 74 75 /* Reduce multiplier and divider by dividing them repeatedly by 10 */ 76 while (((mult % 10U) == 0U) && ((div % 10U) == 0U)) { 77 mult /= 10U; 78 div /= 10U; 79 } 80 81 generic_delay_timer_init_args(mult, div); 82 } 83