RE: [PATCH 1/4] PCI: imx6: Add pci host wakeup support on imx platforms.

[Sherry Sun]

> -----Original Message-----
> From: Lucas Stach <l.stach@xxxxxxxxxxxxxx>
> Sent: 2023年12月8日 18:16
> To: Sherry Sun <sherry.sun@xxxxxxx>; Hongxing Zhu
> <hongxing.zhu@xxxxxxx>; lpieralisi@xxxxxxxxxx; kw@xxxxxxxxx;
> robh@xxxxxxxxxx; bhelgaas@xxxxxxxxxx; krzysztof.kozlowski+dt@xxxxxxxxxx;
> conor+dt@xxxxxxxxxx; shawnguo@xxxxxxxxxx; s.hauer@xxxxxxxxxxxxxx;
> kernel@xxxxxxxxxxxxxx; festevam@xxxxxxxxx
> Cc: dl-linux-imx <linux-imx@xxxxxxx>; linux-pci@xxxxxxxxxxxxxxx; linux-arm-
> kernel@xxxxxxxxxxxxxxxxxxx; devicetree@xxxxxxxxxxxxxxx; linux-
> kernel@xxxxxxxxxxxxxxx
> Subject: Re: [PATCH 1/4] PCI: imx6: Add pci host wakeup support on imx
> platforms.
> 
> Am Freitag, dem 08.12.2023 um 17:13 +0800 schrieb Sherry Sun:
> > Add pci host wakeup feature for imx platforms.
> > Example of configuring the corresponding dts property under the PCI
> > node:
> > host-wake-gpio = <&gpio5 21 GPIO_ACTIVE_LOW>;
> >
> > Signed-off-by: Sherry Sun <sherry.sun@xxxxxxx>
> > Reviewed-by: Richard Zhu <hongxing.zhu@xxxxxxx>
> > ---
> >  drivers/pci/controller/dwc/pci-imx6.c | 69
> > +++++++++++++++++++++++++++
> >  1 file changed, 69 insertions(+)
> >
> > diff --git a/drivers/pci/controller/dwc/pci-imx6.c
> > b/drivers/pci/controller/dwc/pci-imx6.c
> > index 74703362aeec..050c9140f4a3 100644
> > --- a/drivers/pci/controller/dwc/pci-imx6.c
> > +++ b/drivers/pci/controller/dwc/pci-imx6.c
> > @@ -72,6 +72,7 @@ struct imx6_pcie_drvdata {  struct imx6_pcie {
> >  	struct dw_pcie		*pci;
> >  	int			reset_gpio;
> > +	int			host_wake_irq;
> >  	bool			gpio_active_high;
> >  	bool			link_is_up;
> >  	struct clk		*pcie_bus;
> > @@ -1237,11 +1238,46 @@ static int imx6_pcie_resume_noirq(struct
> device *dev)
> >  	return 0;
> >  }
> >
> > +static int imx6_pcie_suspend(struct device *dev) {
> > +	struct imx6_pcie *imx6_pcie = dev_get_drvdata(dev);
> > +
> > +	if (imx6_pcie->host_wake_irq >= 0)
> > +		enable_irq_wake(imx6_pcie->host_wake_irq);
> > +
> > +	return 0;
> > +}
> > +
> > +static int imx6_pcie_resume(struct device *dev) {
> > +	struct imx6_pcie *imx6_pcie = dev_get_drvdata(dev);
> > +
> > +	if (imx6_pcie->host_wake_irq >= 0)
> > +		disable_irq_wake(imx6_pcie->host_wake_irq);
> > +
> > +	return 0;
> > +}
> > +
> >  static const struct dev_pm_ops imx6_pcie_pm_ops = {
> >  	NOIRQ_SYSTEM_SLEEP_PM_OPS(imx6_pcie_suspend_noirq,
> >  				  imx6_pcie_resume_noirq)
> > +	SYSTEM_SLEEP_PM_OPS(imx6_pcie_suspend, imx6_pcie_resume)
> >  };
> >
> > +irqreturn_t host_wake_irq_handler(int irq, void *priv) {
> > +	struct imx6_pcie *imx6_pcie = priv;
> > +	struct device *dev = imx6_pcie->pci->dev;
> > +
> > +	dev_dbg(dev, "%s: host wakeup by pcie", __func__);
> > +
> Not sure how much value this debug print carries. If you want to keep it,
> drop the __func__. There is no other place in this driver handling the wakeup,
> so the function name in the print is pure noise.

Ok, will remove the debug print info here.

> 
> > +	/* Notify PM core we are wakeup source */
> > +	pm_wakeup_event(dev, 0);
> > +	pm_system_wakeup();
> > +
> > +	return IRQ_HANDLED;
> > +}
> > +
> >  static int imx6_pcie_probe(struct platform_device *pdev)  {
> >  	struct device *dev = &pdev->dev;
> > @@ -1250,6 +1286,7 @@ static int imx6_pcie_probe(struct
> platform_device *pdev)
> >  	struct device_node *np;
> >  	struct resource *dbi_base;
> >  	struct device_node *node = dev->of_node;
> > +	struct gpio_desc *host_wake_gpio;
> >  	int ret;
> >  	u16 val;
> >
> > @@ -1457,6 +1494,32 @@ static int imx6_pcie_probe(struct
> platform_device *pdev)
> >  			val |= PCI_MSI_FLAGS_ENABLE;
> >  			dw_pcie_writew_dbi(pci, offset + PCI_MSI_FLAGS,
> val);
> >  		}
> > +
> > +		/* host wakeup support */
> > +		imx6_pcie->host_wake_irq = -1;
> > +		host_wake_gpio = devm_gpiod_get_optional(dev, "host-
> wake", GPIOD_IN);
> > +		if (IS_ERR(host_wake_gpio))
> > +			return PTR_ERR(host_wake_gpio);
> > +
> > +		if (host_wake_gpio != NULL) {
> > +			imx6_pcie->host_wake_irq =
> gpiod_to_irq(host_wake_gpio);
> > +			ret = devm_request_threaded_irq(dev, imx6_pcie-
> >host_wake_irq, NULL,
> > +
> 	host_wake_irq_handler,
> > +							IRQF_ONESHOT |
> IRQF_TRIGGER_FALLING,
> > +							"host_wake",
> imx6_pcie);
> > +			if (ret) {
> > +				dev_err(dev, "Failed to request
> host_wake_irq %d (%d)\n",
> > +					imx6_pcie->host_wake_irq, ret);
> > +				imx6_pcie->host_wake_irq = -1;
> 
> What's the point of resetting host_wake_irq to -1 in those error paths?
> Nobody is going to access this member anymore after the error. Just drop
> this.
> 
> You could simplify all those error paths to if (err)
>     return dev_err_probe(...);

Sounds reasonable, I will remove the host_wake_irq resetting here and use dev_err_probe() instead, thanks!

Best Regards
Sherry