PM / devfreq: tegra: Properly disable interrupts

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.

Reviewed-by: Chanwoo Choi <cw00.choi@samsung.com>
Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
Acked-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: MyungJoo Ham <myungjoo.ham@samsung.com>

1 files changed, 15 insertions, 6 deletions

diff --git a/drivers/devfreq/tegra-devfreq.c b/drivers/devfreq/tegra-devfreq.c
index b923d216a4a9..d88f81fc99de 100644
--- a/drivers/devfreq/tegra-devfreq.c
+++ b/drivers/devfreq/tegra-devfreq.c
@@ -159,6 +159,8 @@ 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 {
@@ -405,6 +407,8 @@ 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];
 
@@ -415,9 +419,14 @@ 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,
@@ -592,7 +601,6 @@ 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);
@@ -661,15 +669,16 @@ 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) {