[PATCH v3 07/16] PM / devfreq: tegra: Properly disable interrupts

[Dmitry Osipenko]

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 <dig...@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) {
-- 
2.21.0