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/*
* 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>
static void __init shmobile_setup_delay_hz(unsigned int max_cpu_core_hz,
unsigned int mult, unsigned int div)
{
/* 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.
*/
unsigned int value = HZ * div / mult;
if (!preset_lpj)
preset_lpj = max_cpu_core_hz / value;
}
void __init shmobile_init_delay(void)
{
struct device_node *np, *cpus;
bool is_a7_a8_a9 = false;
bool is_a15 = false;
bool has_arch_timer = false;
u32 max_freq = 0;
cpus = of_find_node_by_path("/cpus");
if (!cpus)
return;
for_each_child_of_node(cpus, np) {
u32 freq;
if (!of_property_read_u32(np, "clock-frequency", &freq))
max_freq = max(max_freq, freq);
if (of_device_is_compatible(np, "arm,cortex-a8") ||
of_device_is_compatible(np, "arm,cortex-a9")) {
is_a7_a8_a9 = true;
} else if (of_device_is_compatible(np, "arm,cortex-a7")) {
is_a7_a8_a9 = true;
has_arch_timer = true;
} else if (of_device_is_compatible(np, "arm,cortex-a15")) {
is_a15 = true;
has_arch_timer = true;
}
}
of_node_put(cpus);
if (!max_freq)
return;
if (!has_arch_timer || !IS_ENABLED(CONFIG_ARM_ARCH_TIMER)) {
if (is_a7_a8_a9)
shmobile_setup_delay_hz(max_freq, 1, 3);
else if (is_a15)
shmobile_setup_delay_hz(max_freq, 2, 4);
}
}
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