[v3,07/16] PM / devfreq: tegra: Properly disable interrupts
diff mbox series

Message ID 20190417222925.5815-8-digetx@gmail.com
State New
Headers show
Series
  • NVIDIA Tegra devfreq improvements and Tegra20/30 support
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Commit Message

Dmitry Osipenko April 17, 2019, 10:29 p.m. UTC
There is no guarantee that interrupt handling isn't running in parallel
with tegra_actmon_disable_interrupts(), hence it is necessary to protect
DEV_CTRL register accesses and clear IRQ status with ACTMON's IRQ being
disabled in the Interrupt Controller in order to ensure that device
interrupt is indeed being disabled.

Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
---
 drivers/devfreq/tegra-devfreq.c | 21 +++++++++++++++------
 1 file changed, 15 insertions(+), 6 deletions(-)

Comments

Chanwoo Choi April 30, 2019, 12:05 a.m. UTC | #1
On 19. 4. 18. 오전 7:29, Dmitry Osipenko wrote:
> There is no guarantee that interrupt handling isn't running in parallel
> with tegra_actmon_disable_interrupts(), hence it is necessary to protect
> DEV_CTRL register accesses and clear IRQ status with ACTMON's IRQ being
> disabled in the Interrupt Controller in order to ensure that device
> interrupt is indeed being disabled.
> 
> Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
> ---
>  drivers/devfreq/tegra-devfreq.c | 21 +++++++++++++++------
>  1 file changed, 15 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/devfreq/tegra-devfreq.c b/drivers/devfreq/tegra-devfreq.c
> index b65313fe3c2e..ce1eb97a2090 100644
> --- a/drivers/devfreq/tegra-devfreq.c
> +++ b/drivers/devfreq/tegra-devfreq.c
> @@ -171,6 +171,8 @@ struct tegra_devfreq {
>  	struct notifier_block	rate_change_nb;
>  
>  	struct tegra_devfreq_device devices[ARRAY_SIZE(actmon_device_configs)];
> +
> +	int irq;
>  };
>  
>  struct tegra_actmon_emc_ratio {
> @@ -417,6 +419,8 @@ static void tegra_actmon_disable_interrupts(struct tegra_devfreq *tegra)
>  	u32 val;
>  	unsigned int i;
>  
> +	disable_irq(tegra->irq);
> +
>  	for (i = 0; i < ARRAY_SIZE(tegra->devices); i++) {
>  		dev = &tegra->devices[i];
>  
> @@ -427,9 +431,14 @@ static void tegra_actmon_disable_interrupts(struct tegra_devfreq *tegra)
>  		val &= ~ACTMON_DEV_CTRL_CONSECUTIVE_ABOVE_WMARK_EN;
>  
>  		device_writel(dev, val, ACTMON_DEV_CTRL);
> +
> +		device_writel(dev, ACTMON_INTR_STATUS_CLEAR,
> +			      ACTMON_DEV_INTR_STATUS);
>  	}
>  
>  	actmon_write_barrier(tegra);
> +
> +	enable_irq(tegra->irq);
>  }
>  
>  static void tegra_actmon_configure_device(struct tegra_devfreq *tegra,
> @@ -604,7 +613,6 @@ static int tegra_devfreq_probe(struct platform_device *pdev)
>  	struct resource *res;
>  	unsigned int i;
>  	unsigned long rate;
> -	int irq;
>  	int err;
>  
>  	tegra = devm_kzalloc(&pdev->dev, sizeof(*tegra), GFP_KERNEL);
> @@ -673,15 +681,16 @@ static int tegra_devfreq_probe(struct platform_device *pdev)
>  		dev_pm_opp_add(&pdev->dev, rate, 0);
>  	}
>  
> -	irq = platform_get_irq(pdev, 0);
> -	if (irq < 0) {
> -		dev_err(&pdev->dev, "Failed to get IRQ: %d\n", irq);
> -		return irq;
> +	tegra->irq = platform_get_irq(pdev, 0);
> +	if (tegra->irq < 0) {
> +		err = tegra->irq;
> +		dev_err(&pdev->dev, "Failed to get IRQ: %d\n", err);
> +		return err;
>  	}
>  
>  	platform_set_drvdata(pdev, tegra);
>  
> -	err = devm_request_threaded_irq(&pdev->dev, irq, NULL,
> +	err = devm_request_threaded_irq(&pdev->dev, tegra->irq, NULL,
>  					actmon_thread_isr, IRQF_ONESHOT,
>  					"tegra-devfreq", tegra);
>  	if (err) {
> 

It is ok to disable the hardware interrupt line
before completing the some operation about registers
in order to protect the interrupt occur.

Reviewed-by: Chanwoo Choi <cw00.choi@samsung.com>

Patch
diff mbox series

diff --git a/drivers/devfreq/tegra-devfreq.c b/drivers/devfreq/tegra-devfreq.c
index b65313fe3c2e..ce1eb97a2090 100644
--- a/drivers/devfreq/tegra-devfreq.c
+++ b/drivers/devfreq/tegra-devfreq.c
@@ -171,6 +171,8 @@  struct tegra_devfreq {
 	struct notifier_block	rate_change_nb;
 
 	struct tegra_devfreq_device devices[ARRAY_SIZE(actmon_device_configs)];
+
+	int irq;
 };
 
 struct tegra_actmon_emc_ratio {
@@ -417,6 +419,8 @@  static void tegra_actmon_disable_interrupts(struct tegra_devfreq *tegra)
 	u32 val;
 	unsigned int i;
 
+	disable_irq(tegra->irq);
+
 	for (i = 0; i < ARRAY_SIZE(tegra->devices); i++) {
 		dev = &tegra->devices[i];
 
@@ -427,9 +431,14 @@  static void tegra_actmon_disable_interrupts(struct tegra_devfreq *tegra)
 		val &= ~ACTMON_DEV_CTRL_CONSECUTIVE_ABOVE_WMARK_EN;
 
 		device_writel(dev, val, ACTMON_DEV_CTRL);
+
+		device_writel(dev, ACTMON_INTR_STATUS_CLEAR,
+			      ACTMON_DEV_INTR_STATUS);
 	}
 
 	actmon_write_barrier(tegra);
+
+	enable_irq(tegra->irq);
 }
 
 static void tegra_actmon_configure_device(struct tegra_devfreq *tegra,
@@ -604,7 +613,6 @@  static int tegra_devfreq_probe(struct platform_device *pdev)
 	struct resource *res;
 	unsigned int i;
 	unsigned long rate;
-	int irq;
 	int err;
 
 	tegra = devm_kzalloc(&pdev->dev, sizeof(*tegra), GFP_KERNEL);
@@ -673,15 +681,16 @@  static int tegra_devfreq_probe(struct platform_device *pdev)
 		dev_pm_opp_add(&pdev->dev, rate, 0);
 	}
 
-	irq = platform_get_irq(pdev, 0);
-	if (irq < 0) {
-		dev_err(&pdev->dev, "Failed to get IRQ: %d\n", irq);
-		return irq;
+	tegra->irq = platform_get_irq(pdev, 0);
+	if (tegra->irq < 0) {
+		err = tegra->irq;
+		dev_err(&pdev->dev, "Failed to get IRQ: %d\n", err);
+		return err;
 	}
 
 	platform_set_drvdata(pdev, tegra);
 
-	err = devm_request_threaded_irq(&pdev->dev, irq, NULL,
+	err = devm_request_threaded_irq(&pdev->dev, tegra->irq, NULL,
 					actmon_thread_isr, IRQF_ONESHOT,
 					"tegra-devfreq", tegra);
 	if (err) {