On Thu, May 02, 2019 at 02:38:06AM +0300, 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. > > Reviewed-by: Chanwoo Choi <[email protected]> > Signed-off-by: Dmitry Osipenko <[email protected]> > --- > 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;
Interrupts are typically unsigned int.
> };
>
> 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);
Why do we enable interrupts after this? Is there any use in having the
top-level interrupt enabled if nothing's going to generate an interrupt
anyway?
> }
>
> 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;
> }
This is very oddly written. tegra->irq should really be an unsigned int
since that's the standard type for interrupt numbers. But since you need
to be able to detect errors from platform_get_irq() it now becomes
natural to write this as:
err = platform_get_irq(pdev, 0);
if (err < 0) {
dev_err(...);
return err;
}
tegra->irq = err;
Two birds with one stone. I suppose this could be done in a follow-up
patch since it isn't practically wrong in your version, so either way:
Acked-by: Thierry Reding <[email protected]>
signature.asc
Description: PGP signature
