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
21static void __init shmobile_setup_delay_hz(unsigned int max_cpu_core_hz,
22					   unsigned int mult, unsigned int div)
23{
24	/* calculate a worst-case loops-per-jiffy value
25	 * based on maximum cpu core hz setting and the
26	 * __delay() implementation in arch/arm/lib/delay.S
27	 *
28	 * this will result in a longer delay than expected
29	 * when the cpu core runs on lower frequencies.
30	 */
31
32	unsigned int value = HZ * div / mult;
33
34	if (!preset_lpj)
35		preset_lpj = max_cpu_core_hz / value;
36}
37
38void __init shmobile_init_delay(void)
39{
40	struct device_node *np, *cpus;
41	bool is_a7_a8_a9 = false;
42	bool is_a15 = false;
43	bool has_arch_timer = false;
44	u32 max_freq = 0;
45
46	cpus = of_find_node_by_path("/cpus");
47	if (!cpus)
48		return;
49
50	for_each_child_of_node(cpus, np) {
51		u32 freq;
52
53		if (!of_property_read_u32(np, "clock-frequency", &freq))
54			max_freq = max(max_freq, freq);
55
56		if (of_device_is_compatible(np, "arm,cortex-a8") ||
57		    of_device_is_compatible(np, "arm,cortex-a9")) {
58			is_a7_a8_a9 = true;
59		} else if (of_device_is_compatible(np, "arm,cortex-a7")) {
60			is_a7_a8_a9 = true;
61			has_arch_timer = true;
62		} else if (of_device_is_compatible(np, "arm,cortex-a15")) {
63			is_a15 = true;
64			has_arch_timer = true;
65		}
66	}
67
68	of_node_put(cpus);
69
70	if (!max_freq)
71		return;
72
73	if (!has_arch_timer || !IS_ENABLED(CONFIG_ARM_ARCH_TIMER)) {
74		if (is_a7_a8_a9)
75			shmobile_setup_delay_hz(max_freq, 1, 3);
76		else if (is_a15)
77			shmobile_setup_delay_hz(max_freq, 2, 4);
78	}
79}
80