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149 lines
4.0 KiB
149 lines
4.0 KiB
// SPDX-License-Identifier: GPL-2.0-or-later |
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/* |
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* Copyright 2012 Linaro Ltd. |
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*/ |
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#include <linux/cpuidle.h> |
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#include <linux/of.h> |
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#include <linux/of_device.h> |
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#include <asm/cpuidle.h> |
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extern struct of_cpuidle_method __cpuidle_method_of_table[]; |
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static const struct of_cpuidle_method __cpuidle_method_of_table_sentinel |
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__used __section("__cpuidle_method_of_table_end"); |
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static struct cpuidle_ops cpuidle_ops[NR_CPUS] __ro_after_init; |
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/** |
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* arm_cpuidle_simple_enter() - a wrapper to cpu_do_idle() |
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* @dev: not used |
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* @drv: not used |
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* @index: not used |
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* |
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* A trivial wrapper to allow the cpu_do_idle function to be assigned as a |
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* cpuidle callback by matching the function signature. |
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* |
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* Returns the index passed as parameter |
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*/ |
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int arm_cpuidle_simple_enter(struct cpuidle_device *dev, |
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struct cpuidle_driver *drv, int index) |
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{ |
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cpu_do_idle(); |
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return index; |
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} |
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/** |
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* arm_cpuidle_suspend() - function to enter low power idle states |
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* @index: an integer used as an identifier for the low level PM callbacks |
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* |
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* This function calls the underlying arch specific low level PM code as |
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* registered at the init time. |
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* |
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* Returns the result of the suspend callback. |
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*/ |
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int arm_cpuidle_suspend(int index) |
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{ |
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int cpu = smp_processor_id(); |
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return cpuidle_ops[cpu].suspend(index); |
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} |
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/** |
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* arm_cpuidle_get_ops() - find a registered cpuidle_ops by name |
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* @method: the method name |
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* |
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* Search in the __cpuidle_method_of_table array the cpuidle ops matching the |
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* method name. |
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* |
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* Returns a struct cpuidle_ops pointer, NULL if not found. |
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*/ |
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static const struct cpuidle_ops *__init arm_cpuidle_get_ops(const char *method) |
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{ |
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struct of_cpuidle_method *m = __cpuidle_method_of_table; |
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for (; m->method; m++) |
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if (!strcmp(m->method, method)) |
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return m->ops; |
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return NULL; |
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} |
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/** |
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* arm_cpuidle_read_ops() - Initialize the cpuidle ops with the device tree |
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* @dn: a pointer to a struct device node corresponding to a cpu node |
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* @cpu: the cpu identifier |
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* |
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* Get the method name defined in the 'enable-method' property, retrieve the |
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* associated cpuidle_ops and do a struct copy. This copy is needed because all |
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* cpuidle_ops are tagged __initconst and will be unloaded after the init |
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* process. |
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* |
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* Return 0 on sucess, -ENOENT if no 'enable-method' is defined, -EOPNOTSUPP if |
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* no cpuidle_ops is registered for the 'enable-method', or if either init or |
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* suspend callback isn't defined. |
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*/ |
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static int __init arm_cpuidle_read_ops(struct device_node *dn, int cpu) |
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{ |
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const char *enable_method; |
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const struct cpuidle_ops *ops; |
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enable_method = of_get_property(dn, "enable-method", NULL); |
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if (!enable_method) |
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return -ENOENT; |
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ops = arm_cpuidle_get_ops(enable_method); |
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if (!ops) { |
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pr_warn("%pOF: unsupported enable-method property: %s\n", |
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dn, enable_method); |
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return -EOPNOTSUPP; |
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} |
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if (!ops->init || !ops->suspend) { |
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pr_warn("cpuidle_ops '%s': no init or suspend callback\n", |
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enable_method); |
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return -EOPNOTSUPP; |
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} |
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cpuidle_ops[cpu] = *ops; /* structure copy */ |
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pr_notice("cpuidle: enable-method property '%s'" |
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" found operations\n", enable_method); |
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return 0; |
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} |
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/** |
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* arm_cpuidle_init() - Initialize cpuidle_ops for a specific cpu |
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* @cpu: the cpu to be initialized |
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* |
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* Initialize the cpuidle ops with the device for the cpu and then call |
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* the cpu's idle initialization callback. This may fail if the underlying HW |
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* is not operational. |
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* |
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* Returns: |
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* 0 on success, |
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* -ENODEV if it fails to find the cpu node in the device tree, |
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* -EOPNOTSUPP if it does not find a registered and valid cpuidle_ops for |
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* this cpu, |
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* -ENOENT if it fails to find an 'enable-method' property, |
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* -ENXIO if the HW reports a failure or a misconfiguration, |
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* -ENOMEM if the HW report an memory allocation failure |
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*/ |
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int __init arm_cpuidle_init(int cpu) |
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{ |
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struct device_node *cpu_node = of_cpu_device_node_get(cpu); |
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int ret; |
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if (!cpu_node) |
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return -ENODEV; |
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ret = arm_cpuidle_read_ops(cpu_node, cpu); |
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if (!ret) |
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ret = cpuidle_ops[cpu].init(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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