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Commit c3fbbf93 authored by Jisheng Zhang's avatar Jisheng Zhang Committed by Russell King
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ARM: 8586/1: cpuidle: make arm_cpuidle_suspend() a bit more efficient 



Currently, we check cpuidle_ops.suspend every time when entering a
low-power idle state. But this check could be avoided in this hot path
by moving it into arm_cpuidle_read_ops() to reduce arm_cpuidle_suspend
overhead a bit.

Signed-off-by: default avatarJisheng Zhang <jszhang@marvell.com>
Acked-by: default avatarDaniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: default avatarRussell King <rmk+kernel@arm.linux.org.uk>
parent f222a769

arch/arm/kernel/cpuidle.c

+6 −11
Original line number Diff line number Diff line
@@ -47,18 +47,13 @@ int arm_cpuidle_simple_enter(struct cpuidle_device *dev, 
 * 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.

 * Returns the result of the suspend callback.

 */

int arm_cpuidle_suspend(int index)

{

	int ret = -EOPNOTSUPP;

	int cpu = smp_processor_id();



	if (cpuidle_ops[cpu].suspend)

		ret = cpuidle_ops[cpu].suspend(index);



	return ret;

	return cpuidle_ops[cpu].suspend(index);

}



/**
@@ -92,8 +87,8 @@ static const struct cpuidle_ops *__init arm_cpuidle_get_ops(const char *method) 
 * process.

 *

 * Return 0 on sucess, -ENOENT if no 'enable-method' is defined, -EOPNOTSUPP if

 * no cpuidle_ops is registered for the 'enable-method', or if no init callback

 * is defined.

 * no cpuidle_ops is registered for the 'enable-method', or if either init or

 * suspend callback isn't defined.

 */

static int __init arm_cpuidle_read_ops(struct device_node *dn, int cpu)

{
@@ -111,8 +106,8 @@ static int __init arm_cpuidle_read_ops(struct device_node *dn, int cpu) 
		return -EOPNOTSUPP;

	}



	if (!ops->init) {

		pr_warn("cpuidle_ops '%s': no init callback\n",

	if (!ops->init || !ops->suspend) {

		pr_warn("cpuidle_ops '%s': no init or suspend callback\n",

			enable_method);

		return -EOPNOTSUPP;

	}