Re: [PATCH 03/10] memory: tegra: Push suspend/resume into SoC drivers

[Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>]

On 20/04/2021 18:52, Thierry Reding wrote:
> From: Thierry Reding <treding@nvidia.com>
> 
> Continuing the scheme of unification, push suspend/resume callbacks into
> per-SoC driver so that they can be properly parameterized.
> 
> While at it, also move the ->init() callback into the new tegra_mc_ops
> structure to keep things clean.

Please split this part. This is just moving pointer from one structure
to another, quite small change.

The rest of the patchset is quite different - you now call
tegra_mc_suspend() from a per-SoC driver and move the code around.

> 
> Signed-off-by: Thierry Reding <treding@nvidia.com>
> ---
>  drivers/memory/tegra/mc.c       | 24 ++++++++---------------
>  drivers/memory/tegra/tegra186.c | 27 ++++++++++++++++++++++----
>  drivers/memory/tegra/tegra20.c  | 34 ++++++++++++++++++++++++++++++++-
>  include/soc/tegra/mc.h          |  9 +++++++--
>  4 files changed, 71 insertions(+), 23 deletions(-)
> 
> diff --git a/drivers/memory/tegra/mc.c b/drivers/memory/tegra/mc.c
> index b7e104bf6614..2b21131d779c 100644
> --- a/drivers/memory/tegra/mc.c
> +++ b/drivers/memory/tegra/mc.c
> @@ -829,8 +829,8 @@ static int tegra_mc_probe(struct platform_device *pdev)
>  
>  	mc->debugfs.root = debugfs_create_dir("mc", NULL);
>  
> -	if (mc->soc->init) {
> -		err = mc->soc->init(mc);
> +	if (mc->soc->ops && mc->soc->ops->init) {
> +		err = mc->soc->ops->init(mc);
>  		if (err < 0)
>  			dev_err(&pdev->dev, "failed to initialize SoC driver: %d\n",
>  				err);
> @@ -867,30 +867,22 @@ static int tegra_mc_probe(struct platform_device *pdev)
>  	return 0;
>  }
>  
> -static int tegra_mc_suspend(struct device *dev)
> +static int __maybe_unused tegra_mc_suspend(struct device *dev)
>  {
>  	struct tegra_mc *mc = dev_get_drvdata(dev);
> -	int err;
>  
> -	if (IS_ENABLED(CONFIG_TEGRA_IOMMU_GART) && mc->gart) {
> -		err = tegra_gart_suspend(mc->gart);
> -		if (err)
> -			return err;
> -	}
> +	if (mc->soc->ops && mc->soc->ops->suspend)
> +		return mc->soc->ops->suspend(mc);
>  
>  	return 0;
>  }
>  
> -static int tegra_mc_resume(struct device *dev)
> +static int __maybe_unused tegra_mc_resume(struct device *dev)
>  {
>  	struct tegra_mc *mc = dev_get_drvdata(dev);
> -	int err;
>  
> -	if (IS_ENABLED(CONFIG_TEGRA_IOMMU_GART) && mc->gart) {
> -		err = tegra_gart_resume(mc->gart);
> -		if (err)
> -			return err;
> -	}
> +	if (mc->soc->ops && mc->soc->ops->resume)
> +		return mc->soc->ops->resume(mc);
>  
>  	return 0;
>  }
> diff --git a/drivers/memory/tegra/tegra186.c b/drivers/memory/tegra/tegra186.c
> index 8e77567d1378..9d3fdb609d55 100644
> --- a/drivers/memory/tegra/tegra186.c
> +++ b/drivers/memory/tegra/tegra186.c
> @@ -45,6 +45,17 @@ static void tegra186_mc_program_sid(struct tegra_mc *mc)
>  	}
>  }
>  
> +static int tegra186_mc_resume(struct tegra_mc *mc)
> +{
> +	tegra186_mc_program_sid(mc);
> +
> +	return 0;
> +}
> +
> +static const struct tegra_mc_ops tegra186_mc_ops = {
> +	.resume = tegra186_mc_resume,
> +};
> +
>  #if defined(CONFIG_ARCH_TEGRA_186_SOC)
>  static const struct tegra_mc_client tegra186_mc_clients[] = {
>  	{
> @@ -701,6 +712,7 @@ static const struct tegra_mc_client tegra186_mc_clients[] = {
>  static const struct tegra_mc_soc tegra186_mc_soc = {
>  	.num_clients = ARRAY_SIZE(tegra186_mc_clients),
>  	.clients = tegra186_mc_clients,
> +	.ops = &tegra186_mc_ops,
>  };
>  #endif
>  
> @@ -1909,6 +1921,7 @@ static const struct tegra_mc_client tegra194_mc_clients[] = {
>  static const struct tegra_mc_soc tegra194_mc_soc = {
>  	.num_clients = ARRAY_SIZE(tegra194_mc_clients),
>  	.clients = tegra194_mc_clients,
> +	.ops = &tegra186_mc_ops,
>  };
>  #endif
>  
> @@ -1961,22 +1974,28 @@ static const struct of_device_id tegra186_mc_of_match[] = {
>  };
>  MODULE_DEVICE_TABLE(of, tegra186_mc_of_match);
>  
> -static int __maybe_unused tegra186_mc_suspend(struct device *dev)
> +static int __maybe_unused tegra_mc_suspend(struct device *dev)
>  {
> +	struct tegra_mc *mc = dev_get_drvdata(dev);
> +
> +	if (mc->soc->ops && mc->soc->ops->suspend)
> +		return mc->soc->ops->suspend(mc);
> +
>  	return 0;
>  }
>  
> -static int __maybe_unused tegra186_mc_resume(struct device *dev)
> +static int __maybe_unused tegra_mc_resume(struct device *dev)
>  {
>  	struct tegra_mc *mc = dev_get_drvdata(dev);
>  
> -	tegra186_mc_program_sid(mc);
> +	if (mc->soc->ops && mc->soc->ops->resume)
> +		return mc->soc->ops->resume(mc);
>  
>  	return 0;
>  }
>  
>  static const struct dev_pm_ops tegra186_mc_pm_ops = {
> -	SET_SYSTEM_SLEEP_PM_OPS(tegra186_mc_suspend, tegra186_mc_resume)
> +	SET_SYSTEM_SLEEP_PM_OPS(tegra_mc_suspend, tegra_mc_resume)

What's the benefit here? You basically define your own suspend-resume
ops, on top of PM suspend-resume ops... Before it was quite obvious code
- the Tegra186 MC driver had very simple suspend/resume which did simple
job. Now it feels like trickier code to follow - Tegra186 driver calls
it's resume (with the same name as others - another confusion) which is
a simple wrapper calling somewhere else (need to jump to assinment of
resume()).


Best regards,
Krzysztof

_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel