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/*
* 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.
*
* 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.
*
* Copyright (C) 2012 ARM Limited
*
* Author: Will Deacon <will.deacon@arm.com>
*/
#include <linux/init.h>
#include <linux/smp.h>
#include <linux/of.h>
#include <linux/delay.h>
#include <linux/psci.h>
#include <uapi/linux/psci.h>
#include <asm/psci.h>
#include <asm/smp_plat.h>
/*
* psci_smp assumes that the following is true about PSCI:
*
* cpu_suspend Suspend the execution on a CPU
* @state we don't currently describe affinity levels, so just pass 0.
* @entry_point the first instruction to be executed on return
* returns 0 success, < 0 on failure
*
* cpu_off Power down a CPU
* @state we don't currently describe affinity levels, so just pass 0.
* no return on successful call
*
* cpu_on Power up a CPU
* @cpuid cpuid of target CPU, as from MPIDR
* @entry_point the first instruction to be executed on return
* returns 0 success, < 0 on failure
*
* migrate Migrate the context to a different CPU
* @cpuid cpuid of target CPU, as from MPIDR
* returns 0 success, < 0 on failure
*
*/
extern void secondary_startup(void);
static int psci_boot_secondary(unsigned int cpu, struct task_struct *idle)
{
if (psci_ops.cpu_on)
return psci_ops.cpu_on(cpu_logical_map(cpu),
virt_to_idmap(&secondary_startup));
return -ENODEV;
}
#ifdef CONFIG_HOTPLUG_CPU
int psci_cpu_disable(unsigned int cpu)
{
/* Fail early if we don't have CPU_OFF support */
if (!psci_ops.cpu_off)
return -EOPNOTSUPP;
/* Trusted OS will deny CPU_OFF */
if (psci_tos_resident_on(cpu))
return -EPERM;
return 0;
}
void __ref psci_cpu_die(unsigned int cpu)
{
u32 state = PSCI_POWER_STATE_TYPE_POWER_DOWN <<
PSCI_0_2_POWER_STATE_TYPE_SHIFT;
if (psci_ops.cpu_off)
psci_ops.cpu_off(state);
/* We should never return */
panic("psci: cpu %d failed to shutdown\n", cpu);
}
int __ref psci_cpu_kill(unsigned int cpu)
{
int err, i;
if (!psci_ops.affinity_info)
return 1;
/*
* cpu_kill could race with cpu_die and we can
* potentially end up declaring this cpu undead
* while it is dying. So, try again a few times.
*/
for (i = 0; i < 10; i++) {
err = psci_ops.affinity_info(cpu_logical_map(cpu), 0);
if (err == PSCI_0_2_AFFINITY_LEVEL_OFF) {
pr_info("CPU%d killed.\n", cpu);
return 1;
}
msleep(10);
pr_info("Retrying again to check for CPU kill\n");
}
pr_warn("CPU%d may not have shut down cleanly (AFFINITY_INFO reports %d)\n",
cpu, err);
/* Make platform_cpu_kill() fail. */
return 0;
}
#endif
bool __init psci_smp_available(void)
{
/* is cpu_on available at least? */
return (psci_ops.cpu_on != NULL);
}
struct smp_operations __initdata psci_smp_ops = {
.smp_boot_secondary = psci_boot_secondary,
#ifdef CONFIG_HOTPLUG_CPU
.cpu_disable = psci_cpu_disable,
.cpu_die = psci_cpu_die,
.cpu_kill = psci_cpu_kill,
#endif
};
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