1 /* 2 * Copyright (c) 2016, ARM Limited and Contributors. All rights reserved. 3 * 4 * Redistribution and use in source and binary forms, with or without 5 * modification, are permitted provided that the following conditions are met: 6 * 7 * Redistributions of source code must retain the above copyright notice, this 8 * list of conditions and the following disclaimer. 9 * 10 * Redistributions in binary form must reproduce the above copyright notice, 11 * this list of conditions and the following disclaimer in the documentation 12 * and/or other materials provided with the distribution. 13 * 14 * Neither the name of ARM nor the names of its contributors may be used 15 * to endorse or promote products derived from this software without specific 16 * prior written permission. 17 * 18 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" 19 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 20 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 21 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE 22 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 23 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 24 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 25 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 26 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 27 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 28 * POSSIBILITY OF SUCH DAMAGE. 29 */ 30 31 #include <arch_helpers.h> 32 #include <assert.h> 33 #include <bl_common.h> 34 #include <debug.h> 35 #include <delay_timer.h> 36 #include <platform.h> 37 38 /* Ticks elapsed in one second by a signal of 1 MHz */ 39 #define MHZ_TICKS_PER_SEC 1000000 40 41 static timer_ops_t ops; 42 43 static uint32_t get_timer_value(void) 44 { 45 /* 46 * Generic delay timer implementation expects the timer to be a down 47 * counter. We apply bitwise NOT operator to the tick values returned 48 * by read_cntpct_el0() to simulate the down counter. The value is 49 * clipped from 64 to 32 bits. 50 */ 51 return (uint32_t)(~read_cntpct_el0()); 52 } 53 54 void generic_delay_timer_init_args(uint32_t mult, uint32_t div) 55 { 56 ops.get_timer_value = get_timer_value; 57 ops.clk_mult = mult; 58 ops.clk_div = div; 59 60 timer_init(&ops); 61 62 VERBOSE("Generic delay timer configured with mult=%u and div=%u\n", 63 mult, div); 64 } 65 66 void generic_delay_timer_init(void) 67 { 68 /* Value in ticks */ 69 unsigned int mult = MHZ_TICKS_PER_SEC; 70 71 /* Value in ticks per second (Hz) */ 72 unsigned int div = plat_get_syscnt_freq2(); 73 74 /* Reduce multiplier and divider by dividing them repeatedly by 10 */ 75 while ((mult % 10 == 0) && (div % 10 == 0)) { 76 mult /= 10; 77 div /= 10; 78 } 79 80 generic_delay_timer_init_args(mult, div); 81 } 82 83