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 #include <linux/platform_device.h>
17 #include <linux/clocksource.h>
18 #include <linux/delay.h>
19 #include <linux/of_address.h>
23 static void __init
shmobile_setup_delay_hz(unsigned int max_cpu_core_hz
,
24 unsigned int mult
, unsigned int div
)
26 /* calculate a worst-case loops-per-jiffy value
27 * based on maximum cpu core hz setting and the
28 * __delay() implementation in arch/arm/lib/delay.S
30 * this will result in a longer delay than expected
31 * when the cpu core runs on lower frequencies.
34 unsigned int value
= HZ
* div
/ mult
;
37 preset_lpj
= max_cpu_core_hz
/ value
;
40 void __init
shmobile_init_delay(void)
42 struct device_node
*np
, *cpus
;
44 bool has_arch_timer
= false;
47 cpus
= of_find_node_by_path("/cpus");
51 for_each_child_of_node(cpus
, np
) {
54 if (!of_property_read_u32(np
, "clock-frequency", &freq
))
55 max_freq
= max(max_freq
, freq
);
57 if (of_device_is_compatible(np
, "arm,cortex-a8")) {
59 } else if (of_device_is_compatible(np
, "arm,cortex-a9")) {
61 } else if (of_device_is_compatible(np
, "arm,cortex-a7") ||
62 of_device_is_compatible(np
, "arm,cortex-a15")) {
64 has_arch_timer
= true;
70 if (!max_freq
|| !div
)
73 if (!has_arch_timer
|| !IS_ENABLED(CONFIG_ARM_ARCH_TIMER
))
74 shmobile_setup_delay_hz(max_freq
, 1, div
);
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