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 #include "common.h" 22 23 void __init shmobile_init_delay(void) 24 { 25 struct device_node *np, *cpus; 26 u32 max_freq = 0; 27 28 cpus = of_find_node_by_path("/cpus"); 29 if (!cpus) 30 return; 31 32 for_each_child_of_node(cpus, np) { 33 u32 freq; 34 35 if (IS_ENABLED(CONFIG_ARM_ARCH_TIMER) && 36 (of_device_is_compatible(np, "arm,cortex-a7") || 37 of_device_is_compatible(np, "arm,cortex-a15"))) { 38 of_node_put(np); 39 of_node_put(cpus); 40 return; 41 } 42 43 if (!of_property_read_u32(np, "clock-frequency", &freq)) 44 max_freq = max(max_freq, freq); 45 } 46 47 of_node_put(cpus); 48 49 if (!max_freq) 50 return; 51 52 /* 53 * Calculate a worst-case loops-per-jiffy value 54 * based on maximum cpu core hz setting and the 55 * __delay() implementation in arch/arm/lib/delay.S. 56 * 57 * This will result in a longer delay than expected 58 * when the cpu core runs on lower frequencies. 59 */ 60 61 if (!preset_lpj) 62 preset_lpj = max_freq / HZ; 63 } 64