4 * Copyright (C) 2010 Magnus Damm
5 * Copyright (C) 2002 - 2009 Paul Mundt
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.
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.
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
21 #include <linux/platform_device.h>
22 #include <linux/clocksource.h>
23 #include <linux/delay.h>
24 #include <linux/of_address.h>
26 static void __init shmobile_setup_delay_hz(unsigned int max_cpu_core_hz,
27 unsigned int mult, unsigned int div)
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
33 * this will result in a longer delay than expected
34 * when the cpu core runs on lower frequencies.
37 unsigned int value = HZ * div / mult;
40 preset_lpj = max_cpu_core_hz / value;
43 void __init shmobile_init_delay(void)
45 struct device_node *np, *cpus;
46 bool is_a7_a8_a9 = false;
50 cpus = of_find_node_by_path("/cpus");
54 for_each_child_of_node(cpus, np) {
57 if (!of_property_read_u32(np, "clock-frequency", &freq))
58 max_freq = max(max_freq, freq);
60 if (of_device_is_compatible(np, "arm,cortex-a7") ||
61 of_device_is_compatible(np, "arm,cortex-a8") ||
62 of_device_is_compatible(np, "arm,cortex-a9"))
64 else if (of_device_is_compatible(np, "arm,cortex-a15"))
74 shmobile_setup_delay_hz(max_freq, 1, 3);
75 else if (is_a15 && !IS_ENABLED(CONFIG_ARM_ARCH_TIMER))
76 shmobile_setup_delay_hz(max_freq, 2, 4);
79 static void __init shmobile_late_time_init(void)
82 * Make sure all compiled-in early timers register themselves.
84 * Run probe() for two "earlytimer" devices, these will be the
85 * clockevents and clocksource devices respectively. In the event
86 * that only a clockevents device is available, we -ENODEV on the
87 * clocksource and the jiffies clocksource is used transparently
88 * instead. No error handling is necessary here.
90 early_platform_driver_register_all("earlytimer");
91 early_platform_driver_probe("earlytimer", 2, 0);
94 void __init shmobile_earlytimer_init(void)
96 late_time_init = shmobile_late_time_init;