![Lorenzo Pieralisi](/assets/img/avatar_default.png)
Current PSCI code handles idle state entry through the psci_cpu_suspend_enter() API, that takes an idle state index as a parameter and convert the index into a previously initialized power_state parameter before calling the PSCI.CPU_SUSPEND() with it. This is unwieldly, since it forces the PSCI firmware layer to keep track of power_state parameter for every idle state so that the index->power_state conversion can be made in the PSCI firmware layer instead of the CPUidle driver implementations. Move the power_state handling out of drivers/firmware/psci into the respective ACPI/DT PSCI CPUidle backends and convert the psci_cpu_suspend_enter() API to get the power_state parameter as input, which makes it closer to its firmware interface PSCI.CPU_SUSPEND() API. A notable side effect is that the PSCI ACPI/DT CPUidle backends now can directly handle (and if needed update) power_state parameters before handing them over to the PSCI firmware interface to trigger PSCI.CPU_SUSPEND() calls. Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com> Acked-by: Daniel Lezcano <daniel.lezcano@linaro.org> Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org> Reviewed-by: Sudeep Holla <sudeep.holla@arm.com> Cc: Will Deacon <will@kernel.org> Cc: Ulf Hansson <ulf.hansson@linaro.org> Cc: Sudeep Holla <sudeep.holla@arm.com> Cc: Daniel Lezcano <daniel.lezcano@linaro.org> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Mark Rutland <mark.rutland@arm.com> Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net> Signed-off-by: Will Deacon <will@kernel.org>
237 lines
5.1 KiB
C
237 lines
5.1 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* PSCI CPU idle driver.
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*
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* Copyright (C) 2019 ARM Ltd.
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* Author: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
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*/
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#define pr_fmt(fmt) "CPUidle PSCI: " fmt
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#include <linux/cpuidle.h>
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#include <linux/cpumask.h>
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#include <linux/cpu_pm.h>
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/of.h>
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#include <linux/of_device.h>
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#include <linux/psci.h>
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#include <linux/slab.h>
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#include <asm/cpuidle.h>
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#include "dt_idle_states.h"
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static DEFINE_PER_CPU_READ_MOSTLY(u32 *, psci_power_state);
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static int psci_enter_idle_state(struct cpuidle_device *dev,
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struct cpuidle_driver *drv, int idx)
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{
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u32 *state = __this_cpu_read(psci_power_state);
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return CPU_PM_CPU_IDLE_ENTER_PARAM(psci_cpu_suspend_enter,
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idx, state[idx - 1]);
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}
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static struct cpuidle_driver psci_idle_driver __initdata = {
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.name = "psci_idle",
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.owner = THIS_MODULE,
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/*
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* PSCI idle states relies on architectural WFI to
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* be represented as state index 0.
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*/
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.states[0] = {
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.enter = psci_enter_idle_state,
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.exit_latency = 1,
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.target_residency = 1,
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.power_usage = UINT_MAX,
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.name = "WFI",
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.desc = "ARM WFI",
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}
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};
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static const struct of_device_id psci_idle_state_match[] __initconst = {
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{ .compatible = "arm,idle-state",
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.data = psci_enter_idle_state },
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{ },
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};
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static int __init psci_dt_parse_state_node(struct device_node *np, u32 *state)
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{
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int err = of_property_read_u32(np, "arm,psci-suspend-param", state);
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if (err) {
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pr_warn("%pOF missing arm,psci-suspend-param property\n", np);
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return err;
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}
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if (!psci_power_state_is_valid(*state)) {
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pr_warn("Invalid PSCI power state %#x\n", *state);
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return -EINVAL;
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}
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return 0;
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}
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static int __init psci_dt_cpu_init_idle(struct device_node *cpu_node, int cpu)
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{
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int i, ret = 0, count = 0;
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u32 *psci_states;
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struct device_node *state_node;
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/* Count idle states */
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while ((state_node = of_parse_phandle(cpu_node, "cpu-idle-states",
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count))) {
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count++;
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of_node_put(state_node);
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}
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if (!count)
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return -ENODEV;
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psci_states = kcalloc(count, sizeof(*psci_states), GFP_KERNEL);
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if (!psci_states)
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return -ENOMEM;
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for (i = 0; i < count; i++) {
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state_node = of_parse_phandle(cpu_node, "cpu-idle-states", i);
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ret = psci_dt_parse_state_node(state_node, &psci_states[i]);
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of_node_put(state_node);
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if (ret)
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goto free_mem;
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pr_debug("psci-power-state %#x index %d\n", psci_states[i], i);
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}
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/* Idle states parsed correctly, initialize per-cpu pointer */
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per_cpu(psci_power_state, cpu) = psci_states;
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return 0;
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free_mem:
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kfree(psci_states);
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return ret;
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}
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static __init int psci_cpu_init_idle(unsigned int cpu)
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{
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struct device_node *cpu_node;
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int ret;
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/*
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* If the PSCI cpu_suspend function hook has not been initialized
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* idle states must not be enabled, so bail out
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*/
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if (!psci_ops.cpu_suspend)
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return -EOPNOTSUPP;
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cpu_node = of_cpu_device_node_get(cpu);
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if (!cpu_node)
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return -ENODEV;
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ret = psci_dt_cpu_init_idle(cpu_node, cpu);
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of_node_put(cpu_node);
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return ret;
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}
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static int __init psci_idle_init_cpu(int cpu)
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{
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struct cpuidle_driver *drv;
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struct device_node *cpu_node;
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const char *enable_method;
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int ret = 0;
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cpu_node = of_cpu_device_node_get(cpu);
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if (!cpu_node)
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return -ENODEV;
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/*
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* Check whether the enable-method for the cpu is PSCI, fail
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* if it is not.
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*/
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enable_method = of_get_property(cpu_node, "enable-method", NULL);
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if (!enable_method || (strcmp(enable_method, "psci")))
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ret = -ENODEV;
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of_node_put(cpu_node);
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if (ret)
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return ret;
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drv = kmemdup(&psci_idle_driver, sizeof(*drv), GFP_KERNEL);
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if (!drv)
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return -ENOMEM;
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drv->cpumask = (struct cpumask *)cpumask_of(cpu);
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/*
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* Initialize idle states data, starting at index 1, since
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* by default idle state 0 is the quiescent state reached
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* by the cpu by executing the wfi instruction.
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*
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* If no DT idle states are detected (ret == 0) let the driver
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* initialization fail accordingly since there is no reason to
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* initialize the idle driver if only wfi is supported, the
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* default archictectural back-end already executes wfi
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* on idle entry.
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*/
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ret = dt_init_idle_driver(drv, psci_idle_state_match, 1);
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if (ret <= 0) {
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ret = ret ? : -ENODEV;
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goto out_kfree_drv;
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}
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/*
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* Initialize PSCI idle states.
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*/
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ret = psci_cpu_init_idle(cpu);
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if (ret) {
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pr_err("CPU %d failed to PSCI idle\n", cpu);
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goto out_kfree_drv;
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}
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ret = cpuidle_register(drv, NULL);
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if (ret)
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goto out_kfree_drv;
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return 0;
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out_kfree_drv:
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kfree(drv);
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return ret;
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}
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/*
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* psci_idle_init - Initializes PSCI cpuidle driver
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*
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* Initializes PSCI cpuidle driver for all CPUs, if any CPU fails
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* to register cpuidle driver then rollback to cancel all CPUs
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* registration.
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*/
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static int __init psci_idle_init(void)
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{
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int cpu, ret;
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struct cpuidle_driver *drv;
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struct cpuidle_device *dev;
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for_each_possible_cpu(cpu) {
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ret = psci_idle_init_cpu(cpu);
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if (ret)
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goto out_fail;
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}
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return 0;
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out_fail:
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while (--cpu >= 0) {
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dev = per_cpu(cpuidle_devices, cpu);
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drv = cpuidle_get_cpu_driver(dev);
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cpuidle_unregister(drv);
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kfree(drv);
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}
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return ret;
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}
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device_initcall(psci_idle_init);
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