diff options
Diffstat (limited to 'arch/arm/kernel')
-rw-r--r-- | arch/arm/kernel/cpuidle.c | 133 |
1 files changed, 132 insertions, 1 deletions
diff --git a/arch/arm/kernel/cpuidle.c b/arch/arm/kernel/cpuidle.c index 89545f6c8403..318da33465f4 100644 --- a/arch/arm/kernel/cpuidle.c +++ b/arch/arm/kernel/cpuidle.c @@ -10,8 +10,28 @@ */ #include <linux/cpuidle.h> -#include <asm/proc-fns.h> +#include <linux/of.h> +#include <linux/of_device.h> +#include <asm/cpuidle.h> +extern struct of_cpuidle_method __cpuidle_method_of_table[]; + +static const struct of_cpuidle_method __cpuidle_method_of_table_sentinel + __used __section(__cpuidle_method_of_table_end); + +static struct cpuidle_ops cpuidle_ops[NR_CPUS]; + +/** + * arm_cpuidle_simple_enter() - a wrapper to cpu_do_idle() + * @dev: not used + * @drv: not used + * @index: not used + * + * A trivial wrapper to allow the cpu_do_idle function to be assigned as a + * cpuidle callback by matching the function signature. + * + * Returns the index passed as parameter + */ int arm_cpuidle_simple_enter(struct cpuidle_device *dev, struct cpuidle_driver *drv, int index) { @@ -19,3 +39,114 @@ int arm_cpuidle_simple_enter(struct cpuidle_device *dev, return index; } + +/** + * arm_cpuidle_suspend() - function to enter low power idle states + * @index: an integer used as an identifier for the low level PM callbacks + * + * This function calls the underlying arch specific low level PM code as + * registered at the init time. + * + * Returns -EOPNOTSUPP if no suspend callback is defined, the result of the + * callback otherwise. + */ +int arm_cpuidle_suspend(int index) +{ + int ret = -EOPNOTSUPP; + int cpu = smp_processor_id(); + + if (cpuidle_ops[cpu].suspend) + ret = cpuidle_ops[cpu].suspend(cpu, index); + + return ret; +} + +/** + * arm_cpuidle_get_ops() - find a registered cpuidle_ops by name + * @method: the method name + * + * Search in the __cpuidle_method_of_table array the cpuidle ops matching the + * method name. + * + * Returns a struct cpuidle_ops pointer, NULL if not found. + */ +static struct cpuidle_ops *__init arm_cpuidle_get_ops(const char *method) +{ + struct of_cpuidle_method *m = __cpuidle_method_of_table; + + for (; m->method; m++) + if (!strcmp(m->method, method)) + return m->ops; + + return NULL; +} + +/** + * arm_cpuidle_read_ops() - Initialize the cpuidle ops with the device tree + * @dn: a pointer to a struct device node corresponding to a cpu node + * @cpu: the cpu identifier + * + * Get the method name defined in the 'enable-method' property, retrieve the + * associated cpuidle_ops and do a struct copy. This copy is needed because all + * cpuidle_ops are tagged __initdata and will be unloaded after the init + * process. + * + * Return 0 on sucess, -ENOENT if no 'enable-method' is defined, -EOPNOTSUPP if + * no cpuidle_ops is registered for the 'enable-method'. + */ +static int __init arm_cpuidle_read_ops(struct device_node *dn, int cpu) +{ + const char *enable_method; + struct cpuidle_ops *ops; + + enable_method = of_get_property(dn, "enable-method", NULL); + if (!enable_method) + return -ENOENT; + + ops = arm_cpuidle_get_ops(enable_method); + if (!ops) { + pr_warn("%s: unsupported enable-method property: %s\n", + dn->full_name, enable_method); + return -EOPNOTSUPP; + } + + cpuidle_ops[cpu] = *ops; /* structure copy */ + + pr_notice("cpuidle: enable-method property '%s'" + " found operations\n", enable_method); + + return 0; +} + +/** + * arm_cpuidle_init() - Initialize cpuidle_ops for a specific cpu + * @cpu: the cpu to be initialized + * + * Initialize the cpuidle ops with the device for the cpu and then call + * the cpu's idle initialization callback. This may fail if the underlying HW + * is not operational. + * + * Returns: + * 0 on success, + * -ENODEV if it fails to find the cpu node in the device tree, + * -EOPNOTSUPP if it does not find a registered cpuidle_ops for this cpu, + * -ENOENT if it fails to find an 'enable-method' property, + * -ENXIO if the HW reports a failure or a misconfiguration, + * -ENOMEM if the HW report an memory allocation failure + */ +int __init arm_cpuidle_init(int cpu) +{ + struct device_node *cpu_node = of_cpu_device_node_get(cpu); + int ret; + + if (!cpu_node) + return -ENODEV; + + ret = arm_cpuidle_read_ops(cpu_node, cpu); + if (!ret && cpuidle_ops[cpu].init) + ret = cpuidle_ops[cpu].init(cpu_node, cpu); + + of_node_put(cpu_node); + + return ret; +} |