Re: [PATCH v4 02/24] PM / devfreq: tegra30: Keep interrupt disabled while governor is stopped

Chanwoo Choi
2019-07-16T11:47:05Z

On 19. 7. 8. 오전 7:32, Dmitry Osipenko wrote:
> There is no real need to keep interrupt always-enabled, will be nicer
> to keep it disabled while governor is inactive.
>
> Suggested-by: Thierry Reding <thierry.reding@gmail.com>
> Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
> ---
> drivers/devfreq/tegra30-devfreq.c | 43 ++++++++++++++++---------------
> 1 file changed, 22 insertions(+), 21 deletions(-)
>
> diff --git a/drivers/devfreq/tegra30-devfreq.c b/drivers/devfreq/tegra30-devfreq.c
> index a27300f40b0b..5e2b133babdd 100644
> --- a/drivers/devfreq/tegra30-devfreq.c
> +++ b/drivers/devfreq/tegra30-devfreq.c
> @@ -11,6 +11,7 @@
> #include <linux/devfreq.h>
> #include <linux/interrupt.h>
> #include <linux/io.h>
> +#include <linux/irq.h>
> #include <linux/module.h>
> #include <linux/mod_devicetable.h>
> #include <linux/platform_device.h>
> @@ -416,8 +417,6 @@ static void tegra_actmon_start(struct tegra_devfreq *tegra)
> {
> unsigned int i;
>
> - disable_irq(tegra->irq);
> -
> actmon_writel(tegra, ACTMON_SAMPLING_PERIOD - 1,
> ACTMON_GLB_PERIOD_CTRL);
>
> @@ -442,8 +441,6 @@ static void tegra_actmon_stop(struct tegra_devfreq *tegra)
> }
>
> actmon_write_barrier(tegra);
> -
> - enable_irq(tegra->irq);
> }
>
> static int tegra_devfreq_target(struct device *dev, unsigned long *freq,
> @@ -552,6 +549,12 @@ static int tegra_governor_event_handler(struct devfreq *devfreq,
> {
> struct tegra_devfreq *tegra = dev_get_drvdata(devfreq->dev.parent);
>
> + /*
> + * Couple device with the governor early as it is needed at
> + * the moment of governor's start (used by ISR).
> + */
> + tegra->devfreq = devfreq;

I'm not sure it is necessary. Almost devfreq device get
the devfreq instance on probe timing through devfreq_add_device directly.

> +
> switch (event) {
> case DEVFREQ_GOV_START:
> devfreq_monitor_start(devfreq);
> @@ -586,10 +589,11 @@ static struct devfreq_governor tegra_devfreq_governor = {
>
> static int tegra_devfreq_probe(struct platform_device *pdev)
> {
> - struct tegra_devfreq *tegra;
> struct tegra_devfreq_device *dev;
> - unsigned int i;
> + struct tegra_devfreq *tegra;
> + struct devfreq *devfreq;
> unsigned long rate;
> + unsigned int i;
> int err;
>
> tegra = devm_kzalloc(&pdev->dev, sizeof(*tegra), GFP_KERNEL);
> @@ -625,6 +629,16 @@ static int tegra_devfreq_probe(struct platform_device *pdev)
> }
> tegra->irq = err;
>
> + irq_set_status_flags(tegra->irq, IRQ_NOAUTOEN);
> +
> + err = devm_request_threaded_irq(&pdev->dev, tegra->irq, NULL,
> + actmon_thread_isr, IRQF_ONESHOT,
> + "tegra-devfreq", tegra);
> + if (err) {
> + dev_err(&pdev->dev, "Interrupt request failed: %d\n", err);
> + return err;
> + }
> +
> reset_control_assert(tegra->reset);
>
> err = clk_prepare_enable(tegra->clock);
> @@ -672,28 +686,15 @@ static int tegra_devfreq_probe(struct platform_device *pdev)
> }
>
> tegra_devfreq_profile.initial_freq = clk_get_rate(tegra->emc_clock);
> - tegra->devfreq = devfreq_add_device(&pdev->dev,
> - &tegra_devfreq_profile,
> - "tegra_actmon",
> - NULL);
> + devfreq = devfreq_add_device(&pdev->dev, &tegra_devfreq_profile,
> + "tegra_actmon", NULL);
> if (IS_ERR(tegra->devfreq)) {

Have to check 'devfreq' instead of 'tegra->devfreq'.
Did you test it? It might be failed because 'tegra->devfreq is NULL.

> err = PTR_ERR(tegra->devfreq);

ditto.

> goto remove_governor;
> }
>
> - err = devm_request_threaded_irq(&pdev->dev, tegra->irq, NULL,
> - actmon_thread_isr, IRQF_ONESHOT,
> - "tegra-devfreq", tegra);
> - if (err) {
> - dev_err(&pdev->dev, "Interrupt request failed: %d\n", err);
> - goto remove_devfreq;
> - }
> -
> return 0;
>
> -remove_devfreq:
> - devfreq_remove_device(tegra->devfreq);
> -
> remove_governor:
> devfreq_remove_governor(&tegra_devfreq_governor);
>
>

--
Best Regards,
Chanwoo Choi
Samsung Electronics