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 #include <linux/platform_device.h> 17 #include <linux/clocksource.h> 18 #include <linux/delay.h> 19 #include <linux/of_address.h> 20 21 static void __init shmobile_setup_delay_hz(unsigned int max_cpu_core_hz, 22 unsigned int mult, unsigned int div) 23 { 24 /* calculate a worst-case loops-per-jiffy value 25 * based on maximum cpu core hz setting and the 26 * __delay() implementation in arch/arm/lib/delay.S 27 * 28 * this will result in a longer delay than expected 29 * when the cpu core runs on lower frequencies. 30 */ 31 32 unsigned int value = HZ * div / mult; 33 34 if (!preset_lpj) 35 preset_lpj = max_cpu_core_hz / value; 36 } 37 38 void __init shmobile_init_delay(void) 39 { 40 struct device_node *np, *cpus; 41 bool is_a7_a8_a9 = false; 42 bool is_a15 = false; 43 bool has_arch_timer = false; 44 u32 max_freq = 0; 45 46 cpus = of_find_node_by_path("/cpus"); 47 if (!cpus) 48 return; 49 50 for_each_child_of_node(cpus, np) { 51 u32 freq; 52 53 if (!of_property_read_u32(np, "clock-frequency", &freq)) 54 max_freq = max(max_freq, freq); 55 56 if (of_device_is_compatible(np, "arm,cortex-a8") || 57 of_device_is_compatible(np, "arm,cortex-a9")) { 58 is_a7_a8_a9 = true; 59 } else if (of_device_is_compatible(np, "arm,cortex-a7")) { 60 is_a7_a8_a9 = true; 61 has_arch_timer = true; 62 } else if (of_device_is_compatible(np, "arm,cortex-a15")) { 63 is_a15 = true; 64 has_arch_timer = true; 65 } 66 } 67 68 of_node_put(cpus); 69 70 if (!max_freq) 71 return; 72 73 #ifdef CONFIG_ARCH_SHMOBILE_LEGACY 74 /* Non-multiplatform r8a73a4 SoC cannot use arch timer due 75 * to GIC being initialized from C and arch timer via DT */ 76 if (of_machine_is_compatible("renesas,r8a73a4")) 77 has_arch_timer = false; 78 79 /* Non-multiplatform r8a7790 SoC cannot use arch timer due 80 * to GIC being initialized from C and arch timer via DT */ 81 if (of_machine_is_compatible("renesas,r8a7790")) 82 has_arch_timer = false; 83 #endif 84 85 if (!has_arch_timer || !IS_ENABLED(CONFIG_ARM_ARCH_TIMER)) { 86 if (is_a7_a8_a9) 87 shmobile_setup_delay_hz(max_freq, 1, 3); 88 else if (is_a15) 89 shmobile_setup_delay_hz(max_freq, 2, 4); 90 } 91 } 92 93 static void __init shmobile_late_time_init(void) 94 { 95 /* 96 * Make sure all compiled-in early timers register themselves. 97 * 98 * Run probe() for two "earlytimer" devices, these will be the 99 * clockevents and clocksource devices respectively. In the event 100 * that only a clockevents device is available, we -ENODEV on the 101 * clocksource and the jiffies clocksource is used transparently 102 * instead. No error handling is necessary here. 103 */ 104 early_platform_driver_register_all("earlytimer"); 105 early_platform_driver_probe("earlytimer", 2, 0); 106 } 107 108 void __init shmobile_earlytimer_init(void) 109 { 110 late_time_init = shmobile_late_time_init; 111 } 112 113