linux-kernel - Re: [PATCH v4 4/9] usb: cdns3-ti: support reset-on-resume behavior

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Message-ID: <6f9c1ee1-3b3a-44e3-96c6-ae1bef52d51d@kernel.org>
Date: Thu, 7 Mar 2024 14:34:31 +0200
From: Roger Quadros <rogerq@...nel.org>
To: Théo Lebrun <theo.lebrun@...tlin.com>,
 Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
 Rob Herring <robh+dt@...nel.org>,
 Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
 Conor Dooley <conor+dt@...nel.org>, Peter Chen <peter.chen@...nel.org>,
 Pawel Laszczak <pawell@...ence.com>, Nishanth Menon <nm@...com>,
 Vignesh Raghavendra <vigneshr@...com>, Tero Kristo <kristo@...nel.org>
Cc: Thomas Petazzoni <thomas.petazzoni@...tlin.com>,
 Grégory Clement <gregory.clement@...tlin.com>,
 Kevin Hilman <khilman@...nel.org>, Alan Stern <stern@...land.harvard.edu>,
 linux-usb@...r.kernel.org, devicetree@...r.kernel.org,
 linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org
Subject: Re: [PATCH v4 4/9] usb: cdns3-ti: support reset-on-resume behavior



On 07/03/2024 11:55, Théo Lebrun wrote:
> Add match data support, with one boolean to indicate whether the
> hardware resets after a system-wide suspend. If hardware resets, we
> force execute ->runtime_resume() at system-wide resume to run the
> hardware init sequence.
> 
> No compatible exploits this functionality, just yet.
> 
> Signed-off-by: Théo Lebrun <theo.lebrun@...tlin.com>
> ---
>  drivers/usb/cdns3/cdns3-ti.c | 27 +++++++++++++++++++++++++++
>  1 file changed, 27 insertions(+)
> 
> diff --git a/drivers/usb/cdns3/cdns3-ti.c b/drivers/usb/cdns3/cdns3-ti.c
> index 4c8a557e6a6f..f76327566798 100644
> --- a/drivers/usb/cdns3/cdns3-ti.c
> +++ b/drivers/usb/cdns3/cdns3-ti.c
> @@ -57,9 +57,14 @@ struct cdns_ti {
>  	unsigned vbus_divider:1;
>  	struct clk *usb2_refclk;
>  	struct clk *lpm_clk;
> +	const struct cdns_ti_match_data *match_data;
>  	int usb2_refclk_rate_code;
>  };
>  
> +struct cdns_ti_match_data {
> +	bool reset_on_resume;
> +};
> +
>  static const int cdns_ti_rate_table[] = {	/* in KHZ */
>  	9600,
>  	10000,
> @@ -101,6 +106,7 @@ static int cdns_ti_probe(struct platform_device *pdev)
>  	platform_set_drvdata(pdev, data);
>  
>  	data->dev = dev;
> +	data->match_data = device_get_match_data(dev);
>  
>  	data->usbss = devm_platform_ioremap_resource(pdev, 0);
>  	if (IS_ERR(data->usbss)) {
> @@ -220,8 +226,29 @@ static int cdns_ti_runtime_resume(struct device *dev)
>  	return 0;
>  }
>  
> +static int cdns_ti_suspend(struct device *dev)
> +{
> +	struct cdns_ti *data = dev_get_drvdata(dev);
> +
> +	if (data->match_data && data->match_data->reset_on_resume)
> +		return pm_runtime_force_suspend(dev);
> +	else
> +		return 0;
> +}
> +
> +static int cdns_ti_resume(struct device *dev)
> +{
> +	struct cdns_ti *data = dev_get_drvdata(dev);
> +

Instead of this just do Reset and re-init here on affected
platforms.
This is after you remove reset/re-init code from .runtime_resume().

> +	if (data->match_data && data->match_data->reset_on_resume)
> +		return pm_runtime_force_resume(dev);
> +	else
> +		return 0;
> +}
> +
>  static const struct dev_pm_ops cdns_ti_pm_ops = {
>  	RUNTIME_PM_OPS(NULL, cdns_ti_runtime_resume, NULL)
> +	SYSTEM_SLEEP_PM_OPS(cdns_ti_suspend, cdns_ti_resume)
>  };
>  
>  static const struct of_device_id cdns_ti_of_match[] = {
> 

-- 
cheers,
-roger