xref: /openbmc/linux/arch/arm/mach-shmobile/timer.c (revision 20e2fc42)
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * SH-Mobile Timer
4  *
5  * Copyright (C) 2010  Magnus Damm
6  * Copyright (C) 2002 - 2009  Paul Mundt
7  */
8 #include <linux/platform_device.h>
9 #include <linux/clocksource.h>
10 #include <linux/delay.h>
11 #include <linux/of_address.h>
12 
13 #include "common.h"
14 
15 void __init shmobile_init_delay(void)
16 {
17 	struct device_node *np;
18 	u32 max_freq = 0;
19 
20 	for_each_of_cpu_node(np) {
21 		u32 freq;
22 
23 		if (!of_property_read_u32(np, "clock-frequency", &freq))
24 			max_freq = max(max_freq, freq);
25 	}
26 
27 	if (!max_freq)
28 		return;
29 
30 	/*
31 	 * Calculate a worst-case loops-per-jiffy value
32 	 * based on maximum cpu core hz setting and the
33 	 * __delay() implementation in arch/arm/lib/delay.S.
34 	 *
35 	 * This will result in a longer delay than expected
36 	 * when the cpu core runs on lower frequencies.
37 	 */
38 
39 	if (!preset_lpj)
40 		preset_lpj = max_freq / HZ;
41 }
42