[mirror_ubuntu-bionic-kernel.git] / arch / arm / mach-shmobile / timer.c

/*
 * 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"

void __init shmobile_init_delay(void)
{
	struct device_node *np, *cpus;
	u32 max_freq = 0;

	cpus = of_find_node_by_path("/cpus");
	if (!cpus)
		return;

	for_each_child_of_node(cpus, np) {
		u32 freq;

		if (IS_ENABLED(CONFIG_ARM_ARCH_TIMER) &&
		    (of_device_is_compatible(np, "arm,cortex-a7") ||
		     of_device_is_compatible(np, "arm,cortex-a15"))) {
			of_node_put(np);
			of_node_put(cpus);
			return;
		}

		if (!of_property_read_u32(np, "clock-frequency", &freq))
			max_freq = max(max_freq, freq);
	}

	of_node_put(cpus);

	if (!max_freq)
		return;

	/*
	 * 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.
	 */

	if (!preset_lpj)
		preset_lpj = max_freq / HZ;
}
Commit	Line	Data
c793c1b0 MD	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.
c793c1b0 MD	15	*/
c793c1b0 MD	16	#include <linux/platform_device.h>
0583fe47	17	#include <linux/clocksource.h>
0f2c9f20	18	#include <linux/delay.h>
c39dae38	19	#include <linux/of_address.h>
c793c1b0	20
2e41e5fe GU	21	#include "common.h"
2e41e5fe GU	22
c39dae38 MD	23	void __init shmobile_init_delay(void)
c39dae38 MD	24	{
edc8fb1d	25	struct device_node np, cpus;
edc8fb1d LP	26	u32 max_freq = 0;
	27
	28	cpus = of_find_node_by_path("/cpus");
	29	if (!cpus)
	30	return;
	31
	32	for_each_child_of_node(cpus, np) {
	33	u32 freq;
	34
a4b8c18c GU	35	if (IS_ENABLED(CONFIG_ARM_ARCH_TIMER) &&
	36	(of_device_is_compatible(np, "arm,cortex-a7") \|\|
	37	of_device_is_compatible(np, "arm,cortex-a15"))) {
	38	of_node_put(np);
	39	of_node_put(cpus);
	40	return;
	41	}
	42
edc8fb1d LP	43	if (!of_property_read_u32(np, "clock-frequency", &freq))
edc8fb1d LP	44	max_freq = max(max_freq, freq);
c39dae38	45	}
edc8fb1d LP	46
	47	of_node_put(cpus);
	48
a4b8c18c	49	if (!max_freq)
edc8fb1d LP	50	return;
edc8fb1d LP	51
a4b8c18c GU	52	/*
	53	* Calculate a worst-case loops-per-jiffy value
	54	* based on maximum cpu core hz setting and the
	55	* __delay() implementation in arch/arm/lib/delay.S.
	56	*
	57	* This will result in a longer delay than expected
	58	* when the cpu core runs on lower frequencies.
	59	*/
	60
	61	if (!preset_lpj)
	62	preset_lpj = max_freq / HZ;
c39dae38	63	}