| /* |
| * SH-Mobile Timer |
| * |
| * Copyright (C) 2010 Magnus Damm |
| * Copyright (C) 2002 - 2009 Paul Mundt |
| * |
| * This program is free software; you can redistribute it and/or modify |
| * it under the terms of the GNU General Public License as published by |
| * the Free Software Foundation; version 2 of the License. |
| * |
| * This program is distributed in the hope that it will be useful, |
| * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| * GNU General Public License for more details. |
| */ |
| #include <linux/platform_device.h> |
| #include <linux/clocksource.h> |
| #include <linux/delay.h> |
| #include <linux/of_address.h> |
| |
| #include "common.h" |
| |
| static void __init shmobile_setup_delay_hz(unsigned int max_cpu_core_hz, |
| unsigned int mult, unsigned int div) |
| { |
| /* calculate a worst-case loops-per-jiffy value |
| * based on maximum cpu core hz setting and the |
| * __delay() implementation in arch/arm/lib/delay.S |
| * |
| * this will result in a longer delay than expected |
| * when the cpu core runs on lower frequencies. |
| */ |
| |
| unsigned int value = HZ * div / mult; |
| |
| if (!preset_lpj) |
| preset_lpj = max_cpu_core_hz / value; |
| } |
| |
| void __init shmobile_init_delay(void) |
| { |
| struct device_node *np, *cpus; |
| bool is_a7_a8_a9 = false; |
| bool is_a15 = false; |
| bool has_arch_timer = false; |
| u32 max_freq = 0; |
| |
| cpus = of_find_node_by_path("/cpus"); |
| if (!cpus) |
| return; |
| |
| for_each_child_of_node(cpus, np) { |
| u32 freq; |
| |
| if (!of_property_read_u32(np, "clock-frequency", &freq)) |
| max_freq = max(max_freq, freq); |
| |
| if (of_device_is_compatible(np, "arm,cortex-a8") || |
| of_device_is_compatible(np, "arm,cortex-a9")) { |
| is_a7_a8_a9 = true; |
| } else if (of_device_is_compatible(np, "arm,cortex-a7")) { |
| is_a7_a8_a9 = true; |
| has_arch_timer = true; |
| } else if (of_device_is_compatible(np, "arm,cortex-a15")) { |
| is_a15 = true; |
| has_arch_timer = true; |
| } |
| } |
| |
| of_node_put(cpus); |
| |
| if (!max_freq) |
| return; |
| |
| if (!has_arch_timer || !IS_ENABLED(CONFIG_ARM_ARCH_TIMER)) { |
| if (is_a7_a8_a9) |
| shmobile_setup_delay_hz(max_freq, 1, 3); |
| else if (is_a15) |
| shmobile_setup_delay_hz(max_freq, 2, 4); |
| } |
| } |