Re: [PATCH 1/6] remoteproc: imx_rproc: Fix runtime PM cleanup order and error handling

[Mathieu Poirier <mathieu.poirier@linaro.org>]

On Wed, Sep 17, 2025 at 09:19:13PM +0800, Peng Fan wrote:
> The order of runtime PM API calls in the remove path is wrong.
> pm_runtime_put() should be called before pm_runtime_disable(), per the
> runtime PM guidelines.

Where is this mentioned?  I have looked in [1] and couldn't find anything.

[1]. Documentation/power/runtime_pm.rst

> Calling pm_runtime_disable() prematurely can
> lead to incorrect reference counting and improper device suspend behavior.
> 
> Additionally, proper cleanup should be done when rproc_add() fails by
> invoking both pm_runtime_put() and pm_runtime_disable() to avoid leaving
> the device in an inconsistent power state.
> 
> With using devm_pm_runtime_enable() for automatic resource management and
> introducing a devres-managed cleanup action imx_rproc_pm_runtime_put() to
> enforce correct PM API usage and simplify error paths, the upper two
> issues could be fixed. Also print out error log in case of error.
> 
> Fixes: a876a3aacc43 ("remoteproc: imx_rproc: detect and attach to pre-booted remote cores")
> Cc: Ulf Hansson <ulf.hansson@linaro.org>
> Cc: Hiago De Franco <hiago.franco@toradex.com>
> Signed-off-by: Peng Fan <peng.fan@nxp.com>
> ---
>  drivers/remoteproc/imx_rproc.c | 24 +++++++++++++++++++-----
>  1 file changed, 19 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/remoteproc/imx_rproc.c b/drivers/remoteproc/imx_rproc.c
> index bb25221a4a8987ff427d68e2a5535f0e156b0097..12305f36552fb5265b0953a099ea0d561880e3ff 100644
> --- a/drivers/remoteproc/imx_rproc.c
> +++ b/drivers/remoteproc/imx_rproc.c
> @@ -1046,6 +1046,13 @@ static int imx_rproc_sys_off_handler(struct sys_off_data *data)
>  	return NOTIFY_DONE;
>  }
>  
> +static void imx_rproc_pm_runtime_put(void *data)
> +{
> +	struct device *dev = data;
> +
> +	pm_runtime_put(dev);
> +}
> +
>  static int imx_rproc_probe(struct platform_device *pdev)
>  {
>  	struct device *dev = &pdev->dev;
> @@ -1125,12 +1132,23 @@ static int imx_rproc_probe(struct platform_device *pdev)
>  	}
>  
>  	if (dcfg->method == IMX_RPROC_SCU_API) {
> -		pm_runtime_enable(dev);
> +		ret = devm_pm_runtime_enable(dev);
> +		if (ret) {
> +			dev_err(dev, "Failed to enable runtime PM, %d\n", ret);
> +			goto err_put_clk;
> +		}
> +
>  		ret = pm_runtime_resume_and_get(dev);
>  		if (ret) {
>  			dev_err(dev, "pm_runtime get failed: %d\n", ret);
>  			goto err_put_clk;
>  		}
> +
> +		ret = devm_add_action_or_reset(dev, imx_rproc_pm_runtime_put, dev);
> +		if (ret) {
> +			dev_err(dev, "Failed to add devm disable pm action: %d\n", ret);
> +			goto err_put_clk;
> +		}
>  	}
>  
>  	ret = rproc_add(rproc);
> @@ -1158,10 +1176,6 @@ static void imx_rproc_remove(struct platform_device *pdev)
>  	struct rproc *rproc = platform_get_drvdata(pdev);
>  	struct imx_rproc *priv = rproc->priv;
>  
> -	if (priv->dcfg->method == IMX_RPROC_SCU_API) {
> -		pm_runtime_disable(priv->dev);
> -		pm_runtime_put(priv->dev);
> -	}
>  	clk_disable_unprepare(priv->clk);
>  	rproc_del(rproc);
>  	imx_rproc_put_scu(rproc);
> 
> -- 
> 2.37.1
>