mirror of https://gitee.com/openkylin/linux.git
80 lines
2.1 KiB
C
80 lines
2.1 KiB
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>
|
|
|
|
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);
|
|
}
|
|
}
|