From: Dmitry Osipenko digetx@gmail.com
[ Upstream commit 1170433e6611402b869c583fa1fbfd85106ff066 ]
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: Dmitry Osipenko digetx@gmail.com Reviewed-by: Jon Hunter jonathanh@nvidia.com Signed-off-by: Rafael J. Wysocki rafael.j.wysocki@intel.com Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/cpuidle/cpuidle-tegra.c | 34 +++++++++++++++++++-------------- 1 file changed, 20 insertions(+), 14 deletions(-)
diff --git a/drivers/cpuidle/cpuidle-tegra.c b/drivers/cpuidle/cpuidle-tegra.c index 150045849d782..30e6816c6737a 100644 --- a/drivers/cpuidle/cpuidle-tegra.c +++ b/drivers/cpuidle/cpuidle-tegra.c @@ -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 void tegra114_enter_s2idle(struct cpuidle_device *dev,