1 /* 2 * SH-Mobile Timer 3 * 4 * Copyright (C) 2010 Magnus Damm 5 * Copyright (C) 2002 - 2009 Paul Mundt 6 * 7 * This program is free software; you can redistribute it and/or modify 8 * it under the terms of the GNU General Public License as published by 9 * the Free Software Foundation; version 2 of the License. 10 * 11 * This program is distributed in the hope that it will be useful, 12 * but WITHOUT ANY WARRANTY; without even the implied warranty of 13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 14 * GNU General Public License for more details. 15 * 16 * You should have received a copy of the GNU General Public License 17 * along with this program; if not, write to the Free Software 18 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA 19 * 20 */ 21 #include <linux/platform_device.h> 22 #include <linux/clocksource.h> 23 #include <linux/delay.h> 24 #include <linux/of_address.h> 25 26 void __init shmobile_setup_delay_hz(unsigned int max_cpu_core_hz, 27 unsigned int mult, unsigned int div) 28 { 29 /* calculate a worst-case loops-per-jiffy value 30 * based on maximum cpu core hz setting and the 31 * __delay() implementation in arch/arm/lib/delay.S 32 * 33 * this will result in a longer delay than expected 34 * when the cpu core runs on lower frequencies. 35 */ 36 37 unsigned int value = HZ * div / mult; 38 39 if (!preset_lpj) 40 preset_lpj = max_cpu_core_hz / value; 41 } 42 43 void __init shmobile_setup_delay(unsigned int max_cpu_core_mhz, 44 unsigned int mult, unsigned int div) 45 { 46 /* calculate a worst-case loops-per-jiffy value 47 * based on maximum cpu core mhz setting and the 48 * __delay() implementation in arch/arm/lib/delay.S 49 * 50 * this will result in a longer delay than expected 51 * when the cpu core runs on lower frequencies. 52 */ 53 54 unsigned int value = (1000000 * mult) / (HZ * div); 55 56 if (!preset_lpj) 57 preset_lpj = max_cpu_core_mhz * value; 58 } 59 60 void __init shmobile_init_delay(void) 61 { 62 struct device_node *np, *parent; 63 u32 max_freq, freq; 64 65 max_freq = 0; 66 67 parent = of_find_node_by_path("/cpus"); 68 if (parent) { 69 for_each_child_of_node(parent, np) { 70 if (!of_property_read_u32(np, "clock-frequency", &freq)) 71 max_freq = max(max_freq, freq); 72 } 73 of_node_put(parent); 74 } 75 76 if (max_freq) { 77 if (of_find_compatible_node(NULL, NULL, "arm,cortex-a8")) 78 shmobile_setup_delay_hz(max_freq, 1, 3); 79 else if (of_find_compatible_node(NULL, NULL, "arm,cortex-a9")) 80 shmobile_setup_delay_hz(max_freq, 1, 3); 81 else if (of_find_compatible_node(NULL, NULL, "arm,cortex-a15")) 82 if (!IS_ENABLED(CONFIG_ARM_ARCH_TIMER)) 83 shmobile_setup_delay_hz(max_freq, 2, 4); 84 } 85 } 86 87 static void __init shmobile_late_time_init(void) 88 { 89 /* 90 * Make sure all compiled-in early timers register themselves. 91 * 92 * Run probe() for two "earlytimer" devices, these will be the 93 * clockevents and clocksource devices respectively. In the event 94 * that only a clockevents device is available, we -ENODEV on the 95 * clocksource and the jiffies clocksource is used transparently 96 * instead. No error handling is necessary here. 97 */ 98 early_platform_driver_register_all("earlytimer"); 99 early_platform_driver_probe("earlytimer", 2, 0); 100 } 101 102 void __init shmobile_earlytimer_init(void) 103 { 104 late_time_init = shmobile_late_time_init; 105 } 106 107