Commit 1170433e authored by Dmitry Osipenko's avatar Dmitry Osipenko Committed by Rafael J. Wysocki
Browse files

cpuidle: tegra: Correctly handle result of arm_cpuidle_simple_enter() 



The enter() callback of CPUIDLE drivers returns index of the entered idle
state on success or a negative value on failure. The negative value could
any negative value, i.e. it doesn't necessarily needs to be a error code.
That's because CPUIDLE core only cares about the fact of failure and not
about the reason of the enter() failure.

Like every other enter() callback, the arm_cpuidle_simple_enter() returns
the entered idle-index on success. Unlike some of other drivers, it never
fails. It happened that TEGRA_C1=index=err=0 in the code of cpuidle-tegra
driver, and thus, there is no problem for the cpuidle-tegra driver created
by the typo in the code which assumes that the arm_cpuidle_simple_enter()
returns a error code.

The arm_cpuidle_simple_enter() also may return a -ENODEV error if CPU_IDLE
is disabled in a kernel's config, but all CPUIDLE drivers are disabled if
CPU_IDLE is disabled, including the cpuidle-tegra driver. So we can't ever
see the error code from arm_cpuidle_simple_enter() today.

Of course the code may get some changes in the future and then the
typo may transform into a real bug, so let's correct the typo! The
tegra_cpuidle_state_enter() is now changed to make it return the entered
idle-index on success and negative error code on fail, which puts it on
par with the arm_cpuidle_simple_enter(), making code consistent in regards
to the error handling.

This patch fixes a minor typo in the code, it doesn't fix any bugs.

Signed-off-by: default avatarDmitry Osipenko <digetx@gmail.com>
Reviewed-by: default avatarJon Hunter <jonathanh@nvidia.com>
Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
parent ba4f184e

drivers/cpuidle/cpuidle-tegra.c

+20 −14
Original line number Diff line number Diff line
@@ -172,7 +172,7 @@ static int tegra_cpuidle_coupled_barrier(struct cpuidle_device *dev) 
static int tegra_cpuidle_state_enter(struct cpuidle_device *dev,

				     int index, unsigned int cpu)

{

	int ret;

	int err;



	/*

	 * CC6 state is the "CPU cluster power-off" state.  In order to
@@ -183,9 +183,9 @@ static int tegra_cpuidle_state_enter(struct cpuidle_device *dev, 
	 * CPU cores, GIC and L2 cache).

	 */

	if (index == TEGRA_CC6) {

		ret = tegra_cpuidle_coupled_barrier(dev);

		if (ret)

			return ret;

		err = tegra_cpuidle_coupled_barrier(dev);

		if (err)

			return err;

	}



	local_fiq_disable();
@@ -194,15 +194,15 @@ static int tegra_cpuidle_state_enter(struct cpuidle_device *dev, 


	switch (index) {

	case TEGRA_C7:

		ret = tegra_cpuidle_c7_enter();

		err = tegra_cpuidle_c7_enter();

		break;



	case TEGRA_CC6:

		ret = tegra_cpuidle_cc6_enter(cpu);

		err = tegra_cpuidle_cc6_enter(cpu);

		break;



	default:

		ret = -EINVAL;

		err = -EINVAL;

		break;

	}
@@ -210,7 +210,7 @@ static int tegra_cpuidle_state_enter(struct cpuidle_device *dev, 
	tegra_pm_clear_cpu_in_lp2();

	local_fiq_enable();



	return ret;

	return err ?: index;

}



static int tegra_cpuidle_adjust_state_index(int index, unsigned int cpu)
@@ -236,21 +236,27 @@ static int tegra_cpuidle_enter(struct cpuidle_device *dev, 
			       int index)

{

	unsigned int cpu = cpu_logical_map(dev->cpu);

	int err;

	int ret;



	index = tegra_cpuidle_adjust_state_index(index, cpu);

	if (dev->states_usage[index].disable)

		return -1;



	if (index == TEGRA_C1)

		err = arm_cpuidle_simple_enter(dev, drv, index);

		ret = arm_cpuidle_simple_enter(dev, drv, index);

	else

		err = tegra_cpuidle_state_enter(dev, index, cpu);

		ret = tegra_cpuidle_state_enter(dev, index, cpu);



	if (err && (err != -EINTR || index != TEGRA_CC6))

		pr_err_once("failed to enter state %d err: %d\n", index, err);

	if (ret < 0) {

		if (ret != -EINTR || index != TEGRA_CC6)

			pr_err_once("failed to enter state %d err: %d\n",

				    index, ret);

		index = -1;

	} else {

		index = ret;

	}



	return err ? -1 : index;

	return index;

}



static int tegra114_enter_s2idle(struct cpuidle_device *dev,