1 /* 2 * Copyright (c) 2016-2019, 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 get_timer_value(void)21static uint32_t get_timer_value(void) 22 { 23 /* 24 * Generic delay timer implementation expects the timer to be a down 25 * counter. We apply bitwise NOT operator to the tick values returned 26 * by read_cntpct_el0() to simulate the down counter. The value is 27 * clipped from 64 to 32 bits. 28 */ 29 return (uint32_t)(~read_cntpct_el0()); 30 } 31 generic_delay_timer_init_args(uint32_t mult,uint32_t div)32void generic_delay_timer_init_args(uint32_t mult, uint32_t div) 33 { 34 ops.get_timer_value = get_timer_value; 35 ops.clk_mult = mult; 36 ops.clk_div = div; 37 38 timer_init(&ops); 39 40 VERBOSE("Generic delay timer configured with mult=%u and div=%u\n", 41 mult, div); 42 } 43 generic_delay_timer_init(void)44void generic_delay_timer_init(void) 45 { 46 assert(is_armv7_gentimer_present()); 47 48 /* Value in ticks */ 49 unsigned int mult = MHZ_TICKS_PER_SEC; 50 51 /* Value in ticks per second (Hz) */ 52 unsigned int div = plat_get_syscnt_freq2(); 53 54 /* Reduce multiplier and divider by dividing them repeatedly by 10 */ 55 while (((mult % 10U) == 0U) && ((div % 10U) == 0U)) { 56 mult /= 10U; 57 div /= 10U; 58 } 59 60 generic_delay_timer_init_args(mult, div); 61 } 62 63