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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) 2013 ARM Limited
*
* Author: Will Deacon <will.deacon@arm.com>
*/
#define pr_fmt(fmt) "psci: " fmt
#include <linux/init.h>
#include <linux/of.h>
#include <linux/smp.h>
#include <linux/delay.h>
#include <linux/psci.h>
#include <linux/slab.h>
#include <uapi/linux/psci.h>
#include <asm/compiler.h>
#include <asm/cpu_ops.h>
#include <asm/errno.h>
#include <asm/smp_plat.h>
#include <asm/suspend.h>
static bool psci_power_state_loses_context(u32 state)
{
return state & PSCI_0_2_POWER_STATE_TYPE_MASK;
}
static bool psci_power_state_is_valid(u32 state)
{
const u32 valid_mask = PSCI_0_2_POWER_STATE_ID_MASK |
PSCI_0_2_POWER_STATE_TYPE_MASK |
PSCI_0_2_POWER_STATE_AFFL_MASK;
return !(state & ~valid_mask);
}
static DEFINE_PER_CPU_READ_MOSTLY(u32 *, psci_power_state);
static int __maybe_unused cpu_psci_cpu_init_idle(unsigned int cpu)
{
int i, ret, count = 0;
u32 *psci_states;
struct device_node *state_node, *cpu_node;
cpu_node = of_get_cpu_node(cpu, NULL);
if (!cpu_node)
return -ENODEV;
/*
* If the PSCI cpu_suspend function hook has not been initialized
* idle states must not be enabled, so bail out
*/
if (!psci_ops.cpu_suspend)
return -EOPNOTSUPP;
/* Count idle states */
while ((state_node = of_parse_phandle(cpu_node, "cpu-idle-states",
count))) {
count++;
of_node_put(state_node);
}
if (!count)
return -ENODEV;
psci_states = kcalloc(count, sizeof(*psci_states), GFP_KERNEL);
if (!psci_states)
return -ENOMEM;
for (i = 0; i < count; i++) {
u32 state;
state_node = of_parse_phandle(cpu_node, "cpu-idle-states", i);
ret = of_property_read_u32(state_node,
"arm,psci-suspend-param",
&state);
if (ret) {
pr_warn(" * %s missing arm,psci-suspend-param property\n",
state_node->full_name);
of_node_put(state_node);
goto free_mem;
}
of_node_put(state_node);
pr_debug("psci-power-state %#x index %d\n", state, i);
if (!psci_power_state_is_valid(state)) {
pr_warn("Invalid PSCI power state %#x\n", state);
ret = -EINVAL;
goto free_mem;
}
psci_states[i] = state;
}
/* Idle states parsed correctly, initialize per-cpu pointer */
per_cpu(psci_power_state, cpu) = psci_states;
return 0;
free_mem:
kfree(psci_states);
return ret;
}
#ifdef CONFIG_SMP
static int __init cpu_psci_cpu_init(unsigned int cpu)
{
return 0;
}
static int __init cpu_psci_cpu_prepare(unsigned int cpu)
{
if (!psci_ops.cpu_on) {
pr_err("no cpu_on method, not booting CPU%d\n", cpu);
return -ENODEV;
}
return 0;
}
static int cpu_psci_cpu_boot(unsigned int cpu)
{
int err = psci_ops.cpu_on(cpu_logical_map(cpu), __pa(secondary_entry));
if (err)
pr_err("failed to boot CPU%d (%d)\n", cpu, err);
return err;
}
#ifdef CONFIG_HOTPLUG_CPU
static int cpu_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;
}
static void cpu_psci_cpu_die(unsigned int cpu)
{
int ret;
/*
* There are no known implementations of PSCI actually using the
* power state field, pass a sensible default for now.
*/
u32 state = PSCI_POWER_STATE_TYPE_POWER_DOWN <<
PSCI_0_2_POWER_STATE_TYPE_SHIFT;
ret = psci_ops.cpu_off(state);
pr_crit("unable to power off CPU%u (%d)\n", cpu, ret);
}
static int cpu_psci_cpu_kill(unsigned int cpu)
{
int err, i;
if (!psci_ops.affinity_info)
return 0;
/*
* 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 0;
}
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);
return -ETIMEDOUT;
}
#endif
#endif
static int psci_suspend_finisher(unsigned long index)
{
u32 *state = __this_cpu_read(psci_power_state);
return psci_ops.cpu_suspend(state[index - 1],
virt_to_phys(cpu_resume));
}
static int __maybe_unused cpu_psci_cpu_suspend(unsigned long index)
{
int ret;
u32 *state = __this_cpu_read(psci_power_state);
/*
* idle state index 0 corresponds to wfi, should never be called
* from the cpu_suspend operations
*/
if (WARN_ON_ONCE(!index))
return -EINVAL;
if (!psci_power_state_loses_context(state[index - 1]))
ret = psci_ops.cpu_suspend(state[index - 1], 0);
else
ret = cpu_suspend(index, psci_suspend_finisher);
return ret;
}
const struct cpu_operations cpu_psci_ops = {
.name = "psci",
#ifdef CONFIG_CPU_IDLE
.cpu_init_idle = cpu_psci_cpu_init_idle,
.cpu_suspend = cpu_psci_cpu_suspend,
#endif
#ifdef CONFIG_SMP
.cpu_init = cpu_psci_cpu_init,
.cpu_prepare = cpu_psci_cpu_prepare,
.cpu_boot = cpu_psci_cpu_boot,
#ifdef CONFIG_HOTPLUG_CPU
.cpu_disable = cpu_psci_cpu_disable,
.cpu_die = cpu_psci_cpu_die,
.cpu_kill = cpu_psci_cpu_kill,
#endif
#endif
};
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