| From 493efea73dfc5e4272483fc6b7ac174d440ab4ff Mon Sep 17 00:00:00 2001 |
| From: Sasha Levin <sashal@kernel.org> |
| Date: Thu, 9 Jul 2020 20:35:32 +0300 |
| Subject: cpuidle: tegra: Correctly handle result of arm_cpuidle_simple_enter() |
| |
| 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 a12fb141875a7..e8956706a2917 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 int tegra114_enter_s2idle(struct cpuidle_device *dev, |
| -- |
| 2.27.0 |
| |