platsmp-scu.c
2.35 KB
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/*
* SMP support for SoCs with SCU covered by mach-shmobile
*
* Copyright (C) 2013 Magnus Damm
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#include <linux/cpu.h>
#include <linux/delay.h>
#include <linux/init.h>
#include <linux/io.h>
#include <linux/smp.h>
#include <asm/cacheflush.h>
#include <asm/smp_plat.h>
#include <asm/smp_scu.h>
#include <mach/common.h>
static int shmobile_smp_scu_notifier_call(struct notifier_block *nfb,
unsigned long action, void *hcpu)
{
unsigned int cpu = (long)hcpu;
switch (action) {
case CPU_UP_PREPARE:
/* For this particular CPU register SCU SMP boot vector */
shmobile_smp_hook(cpu, virt_to_phys(shmobile_boot_scu),
(unsigned long)shmobile_scu_base);
break;
};
return NOTIFY_OK;
}
static struct notifier_block shmobile_smp_scu_notifier = {
.notifier_call = shmobile_smp_scu_notifier_call,
};
void __init shmobile_smp_scu_prepare_cpus(unsigned int max_cpus)
{
/* install boot code shared by all CPUs */
shmobile_boot_fn = virt_to_phys(shmobile_smp_boot);
shmobile_boot_arg = MPIDR_HWID_BITMASK;
/* enable SCU and cache coherency on booting CPU */
scu_enable(shmobile_scu_base);
scu_power_mode(shmobile_scu_base, SCU_PM_NORMAL);
/* Use CPU notifier for reset vector control */
register_cpu_notifier(&shmobile_smp_scu_notifier);
}
#ifdef CONFIG_HOTPLUG_CPU
void shmobile_smp_scu_cpu_die(unsigned int cpu)
{
/* For this particular CPU deregister boot vector */
shmobile_smp_hook(cpu, 0, 0);
dsb();
flush_cache_all();
/* disable cache coherency */
scu_power_mode(shmobile_scu_base, SCU_PM_POWEROFF);
/* jump to shared mach-shmobile sleep / reset code */
shmobile_smp_sleep();
}
static int shmobile_smp_scu_psr_core_disabled(int cpu)
{
unsigned long mask = SCU_PM_POWEROFF << (cpu * 8);
if ((__raw_readl(shmobile_scu_base + 8) & mask) == mask)
return 1;
return 0;
}
int shmobile_smp_scu_cpu_kill(unsigned int cpu)
{
int k;
/* this function is running on another CPU than the offline target,
* here we need wait for shutdown code in platform_cpu_die() to
* finish before asking SoC-specific code to power off the CPU core.
*/
for (k = 0; k < 1000; k++) {
if (shmobile_smp_scu_psr_core_disabled(cpu))
return 1;
mdelay(1);
}
return 0;
}
#endif