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author | Daniel Lezcano <daniel.lezcano@linaro.org> | 2015-03-24 10:49:55 +0100 |
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committer | Daniel Lezcano <daniel.lezcano@linaro.org> | 2015-03-25 09:53:43 +0100 |
commit | 9a309d6fd213911321acbfe839e0bdb3a7a9f4bf (patch) | |
tree | 9f29da7fa458f6a6a88048a14e7f510edfb84fa7 /arch/arm/kernel/cpuidle.c | |
parent | a0d46a3dfdc3f3d639b3fa84b84a58e116e4bf2c (diff) | |
download | op-kernel-dev-9a309d6fd213911321acbfe839e0bdb3a7a9f4bf.zip op-kernel-dev-9a309d6fd213911321acbfe839e0bdb3a7a9f4bf.tar.gz |
ARM: cpuidle: Document the code
Add kernel-doc format documentation in the code.
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Diffstat (limited to 'arch/arm/kernel/cpuidle.c')
-rw-r--r-- | arch/arm/kernel/cpuidle.c | 59 |
1 files changed, 59 insertions, 0 deletions
diff --git a/arch/arm/kernel/cpuidle.c b/arch/arm/kernel/cpuidle.c index 2b0dae3..318da33 100644 --- a/arch/arm/kernel/cpuidle.c +++ b/arch/arm/kernel/cpuidle.c @@ -21,6 +21,17 @@ static const struct of_cpuidle_method __cpuidle_method_of_table_sentinel 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) { @@ -29,6 +40,16 @@ 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; @@ -40,6 +61,15 @@ int arm_cpuidle_suspend(int 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; @@ -51,6 +81,19 @@ static struct cpuidle_ops *__init arm_cpuidle_get_ops(const char *method) 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; @@ -75,6 +118,22 @@ static int __init arm_cpuidle_read_ops(struct device_node *dn, int cpu) 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); |