Re: [PATCH v2 34/48] gpu: host1x: Support power management

[Mikko Perttunen]

On 12/17/20 8:06 PM, Dmitry Osipenko wrote:
> Add suspend/resume and generic power domain support to the Host1x driver.
> This is required for enabling system-wide DVFS and supporting dynamic
> power management using a generic power domain.
>
> Tested-by: Peter Geis <pgwipeout@xxxxxxxxx>
> Tested-by: Nicolas Chauvet <kwizart@xxxxxxxxx>
> Signed-off-by: Dmitry Osipenko <digetx@xxxxxxxxx>
> ---
>   drivers/gpu/host1x/dev.c | 102 ++++++++++++++++++++++++++++++++++-----
>   1 file changed, 91 insertions(+), 11 deletions(-)
>
> diff --git a/drivers/gpu/host1x/dev.c b/drivers/gpu/host1x/dev.c
> index d0ebb70e2fdd..c1525cffe7b1 100644
> --- a/drivers/gpu/host1x/dev.c
> +++ b/drivers/gpu/host1x/dev.c
> @@ -12,6 +12,7 @@
>   #include <linux/module.h>
>   #include <linux/of_device.h>
>   #include <linux/of.h>
> +#include <linux/pm_runtime.h>
>   #include <linux/slab.h>
>   
>   #define CREATE_TRACE_POINTS
> @@ -417,7 +418,7 @@ static int host1x_probe(struct platform_device *pdev)
>   		return err;
>   	}
>   
> -	host->rst = devm_reset_control_get(&pdev->dev, "host1x");
> +	host->rst = devm_reset_control_get_exclusive_released(&pdev->dev, "host1x");
>   	if (IS_ERR(host->rst)) {
>   		err = PTR_ERR(host->rst);
>   		dev_err(&pdev->dev, "failed to get reset: %d\n", err);
> @@ -437,16 +438,15 @@ static int host1x_probe(struct platform_device *pdev)
>   		goto iommu_exit;
>   	}
>   
> -	err = clk_prepare_enable(host->clk);
> -	if (err < 0) {
> -		dev_err(&pdev->dev, "failed to enable clock\n");
> -		goto free_channels;
> -	}
> +	pm_runtime_enable(&pdev->dev);
> +	err = pm_runtime_get_sync(&pdev->dev);
> +	if (err < 0)
> +		goto rpm_disable;
>   
>   	err = reset_control_deassert(host->rst);
>   	if (err < 0) {
>   		dev_err(&pdev->dev, "failed to deassert reset: %d\n", err);
> -		goto unprepare_disable;
> +		goto rpm_disable;
>   	}
>   
>   	err = host1x_syncpt_init(host);
> @@ -485,9 +485,10 @@ static int host1x_probe(struct platform_device *pdev)
>   	host1x_syncpt_deinit(host);
>   reset_assert:
>   	reset_control_assert(host->rst);
> -unprepare_disable:
> -	clk_disable_unprepare(host->clk);
> -free_channels:
> +rpm_disable:
> +	pm_runtime_put(&pdev->dev);
> +	pm_runtime_disable(&pdev->dev);
> +
>   	host1x_channel_list_free(&host->channel_list);
>   iommu_exit:
>   	host1x_iommu_exit(host);
> @@ -504,16 +505,95 @@ static int host1x_remove(struct platform_device *pdev)
>   	host1x_intr_deinit(host);
>   	host1x_syncpt_deinit(host);
>   	reset_control_assert(host->rst);
> -	clk_disable_unprepare(host->clk);
> +	pm_runtime_put(&pdev->dev);
> +	pm_runtime_disable(&pdev->dev);
>   	host1x_iommu_exit(host);
>   
>   	return 0;
>   }
>   
> +static int __maybe_unused host1x_runtime_suspend(struct device *dev)
> +{
> +	struct host1x *host = dev_get_drvdata(dev);
> +
> +	clk_disable_unprepare(host->clk);
> +	reset_control_release(host->rst);
> +
> +	return 0;
> +}
> +
> +static int __maybe_unused host1x_runtime_resume(struct device *dev)
> +{
> +	struct host1x *host = dev_get_drvdata(dev);
> +	int err;
> +
> +	err = reset_control_acquire(host->rst);
> +	if (err) {
> +		dev_err(dev, "failed to acquire reset: %d\n", err);
> +		return err;
> +	}
> +
> +	err = clk_prepare_enable(host->clk);
> +	if (err) {
> +		dev_err(dev, "failed to enable clock: %d\n", err);
> +		goto release_reset;
> +	}
> +
> +	return 0;
> +
> +release_reset:
> +	reset_control_release(host->rst);
> +
> +	return err;
> +}
> +
> +static __maybe_unused int host1x_suspend(struct device *dev)
> +{
> +	struct host1x *host = dev_get_drvdata(dev);
> +	int err;
> +
> +	host1x_syncpt_save(host);
> +
> +	err = pm_runtime_force_suspend(dev);
> +	if (err < 0)
> +		return err;
> +
> +	return 0;
> +}
> +
> +static __maybe_unused int host1x_resume(struct device *dev)
> +{
> +	struct host1x *host = dev_get_drvdata(dev);
> +	struct host1x_channel *channel;
> +	unsigned int index;
> +	int err;
> +
> +	err = pm_runtime_force_resume(dev);
> +	if (err < 0)
> +		return err;
> +
> +	host1x_syncpt_restore(host);

We also need to execute 'host1x_setup_sid_table' upon resume.

cheers,
Mikko

> +
> +	for_each_set_bit(index, host->channel_list.allocated_channels,
> +			 host->info->nb_channels) {
> +		channel = &host->channel_list.channels[index];
> +		host1x_hw_channel_init(host, channel, channel->id);
> +	}
> +
> +	return 0;
> +}
> +
> +static const struct dev_pm_ops host1x_pm = {
> +	SET_RUNTIME_PM_OPS(host1x_runtime_suspend, host1x_runtime_resume,
> +			   NULL)
> +	SET_SYSTEM_SLEEP_PM_OPS(host1x_suspend, host1x_resume)
> +};
> +
>   static struct platform_driver tegra_host1x_driver = {
>   	.driver = {
>   		.name = "tegra-host1x",
>   		.of_match_table = host1x_of_match,
> +		.pm = &host1x_pm,
>   	},
>   	.probe = host1x_probe,
>   	.remove = host1x_remove,