| rjw | 1f88458 | 2022-01-06 17:20:42 +0800 | [diff] [blame^] | 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 | } |