diff options
Diffstat (limited to '')
| -rw-r--r-- | drivers/cpuidle/cpuidle-arm.c | 187 |
1 files changed, 187 insertions, 0 deletions
diff --git a/drivers/cpuidle/cpuidle-arm.c b/drivers/cpuidle/cpuidle-arm.c new file mode 100644 index 000000000..df564d783 --- /dev/null +++ b/drivers/cpuidle/cpuidle-arm.c @@ -0,0 +1,187 @@ +/* + * ARM/ARM64 generic CPU idle driver. + * + * Copyright (C) 2014 ARM Ltd. + * Author: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com> + * + * 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. + */ + +#define pr_fmt(fmt) "CPUidle arm: " fmt + +#include <linux/cpuidle.h> +#include <linux/cpumask.h> +#include <linux/cpu_pm.h> +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/of.h> +#include <linux/slab.h> +#include <linux/topology.h> + +#include <asm/cpuidle.h> + +#include "dt_idle_states.h" + +/* + * arm_enter_idle_state - Programs CPU to enter the specified state + * + * dev: cpuidle device + * drv: cpuidle driver + * idx: state index + * + * Called from the CPUidle framework to program the device to the + * specified target state selected by the governor. + */ +static int arm_enter_idle_state(struct cpuidle_device *dev, + struct cpuidle_driver *drv, int idx) +{ + /* + * Pass idle state index to arm_cpuidle_suspend which in turn + * will call the CPU ops suspend protocol with idle index as a + * parameter. + */ + return CPU_PM_CPU_IDLE_ENTER(arm_cpuidle_suspend, idx); +} + +static struct cpuidle_driver arm_idle_driver __initdata = { + .name = "arm_idle", + .owner = THIS_MODULE, + /* + * State at index 0 is standby wfi and considered standard + * on all ARM platforms. If in some platforms simple wfi + * can't be used as "state 0", DT bindings must be implemented + * to work around this issue and allow installing a special + * handler for idle state index 0. + */ + .states[0] = { + .enter = arm_enter_idle_state, + .exit_latency = 1, + .target_residency = 1, + .power_usage = UINT_MAX, + .name = "WFI", + .desc = "ARM WFI", + } +}; + +static const struct of_device_id arm_idle_state_match[] __initconst = { + { .compatible = "arm,idle-state", + .data = arm_enter_idle_state }, + { }, +}; + +/* + * arm_idle_init_cpu + * + * Registers the arm specific cpuidle driver with the cpuidle + * framework. It relies on core code to parse the idle states + * and initialize them using driver data structures accordingly. + */ +static int __init arm_idle_init_cpu(int cpu) +{ + int ret; + struct cpuidle_driver *drv; + struct cpuidle_device *dev; + + drv = kmemdup(&arm_idle_driver, sizeof(*drv), GFP_KERNEL); + if (!drv) + return -ENOMEM; + + drv->cpumask = (struct cpumask *)cpumask_of(cpu); + + /* + * Initialize idle states data, starting at index 1. This + * driver is DT only, if no DT idle states are detected (ret + * == 0) let the driver initialization fail accordingly since + * there is no reason to initialize the idle driver if only + * wfi is supported. + */ + ret = dt_init_idle_driver(drv, arm_idle_state_match, 1); + if (ret <= 0) { + ret = ret ? : -ENODEV; + goto out_kfree_drv; + } + + /* + * Call arch CPU operations in order to initialize + * idle states suspend back-end specific data + */ + ret = arm_cpuidle_init(cpu); + + /* + * Allow the initialization to continue for other CPUs, if the reported + * failure is a HW misconfiguration/breakage (-ENXIO). + */ + if (ret) { + pr_err("CPU %d failed to init idle CPU ops\n", cpu); + ret = ret == -ENXIO ? 0 : ret; + goto out_kfree_drv; + } + + ret = cpuidle_register_driver(drv); + if (ret) { + if (ret != -EBUSY) + pr_err("Failed to register cpuidle driver\n"); + goto out_kfree_drv; + } + + dev = kzalloc(sizeof(*dev), GFP_KERNEL); + if (!dev) { + ret = -ENOMEM; + goto out_unregister_drv; + } + dev->cpu = cpu; + + ret = cpuidle_register_device(dev); + if (ret) { + pr_err("Failed to register cpuidle device for CPU %d\n", + cpu); + goto out_kfree_dev; + } + + return 0; + +out_kfree_dev: + kfree(dev); +out_unregister_drv: + cpuidle_unregister_driver(drv); +out_kfree_drv: + kfree(drv); + return ret; +} + +/* + * arm_idle_init - Initializes arm cpuidle driver + * + * Initializes arm cpuidle driver for all CPUs, if any CPU fails + * to register cpuidle driver then rollback to cancel all CPUs + * registeration. + */ +static int __init arm_idle_init(void) +{ + int cpu, ret; + struct cpuidle_driver *drv; + struct cpuidle_device *dev; + + for_each_possible_cpu(cpu) { + ret = arm_idle_init_cpu(cpu); + if (ret) + goto out_fail; + } + + return 0; + +out_fail: + while (--cpu >= 0) { + dev = per_cpu(cpuidle_devices, cpu); + drv = cpuidle_get_cpu_driver(dev); + cpuidle_unregister_device(dev); + cpuidle_unregister_driver(drv); + kfree(dev); + kfree(drv); + } + + return ret; +} +device_initcall(arm_idle_init); |