Cc: linux-kernel@vger.kernel.org, bhelgaas@google.com,
        shawn.lin@rock-chips.com, briannorris@chromium.org,
        dianders@chromium.org, Heiko Stuebner <heiko@sntech.de>,
        linux-pci@vger.kernel.org, linux-rockchip@lists.infradead.org,
        linux-arm-kernel@lists.infradead.org
Subject: Re: [RFC PATCH 1/3] PCI: rockchip: Add support for pcie wake irq
To: Jeffy Chen <jeffy.chen@rock-chips.com>
References: <20170816075224.31734-1-jeffy.chen@rock-chips.com>
 <20170816075224.31734-2-jeffy.chen@rock-chips.com>
From: Shawn Lin <shawn.lin@rock-chips.com>
Message-ID: <5440b476-f811-c478-c19a-9ee08005de6b@rock-chips.com>
Date: Wed, 16 Aug 2017 17:00:10 +0800
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Hi Jeffy,

On 2017/8/16 15:52, Jeffy Chen wrote:
> Add support for PCIE_WAKE pin in rockchip pcie driver.
> 
> Signed-off-by: Jeffy Chen <jeffy.chen@rock-chips.com>
> ---
> 
>   drivers/pci/host/pcie-rockchip.c | 58 ++++++++++++++++++++++++++++++++++++++++
>   1 file changed, 58 insertions(+)
> 
> diff --git a/drivers/pci/host/pcie-rockchip.c b/drivers/pci/host/pcie-rockchip.c
> index 7bb9870f6d8c..f969a6d3cd85 100644
> --- a/drivers/pci/host/pcie-rockchip.c
> +++ b/drivers/pci/host/pcie-rockchip.c
> @@ -38,6 +38,7 @@
>   #include <linux/platform_device.h>
>   #include <linux/reset.h>
>   #include <linux/regmap.h>
> +#include <linux/suspend.h>
>   
>   /*
>    * The upper 16 bits of PCIE_CLIENT_CONFIG are a write mask for the lower 16
> @@ -226,6 +227,8 @@ struct rockchip_pcie {
>   	struct	regulator *vpcie1v8; /* 1.8V power supply */
>   	struct	regulator *vpcie0v9; /* 0.9V power supply */
>   	struct	gpio_desc *ep_gpio;
> +	int	wake_irq;
> +	bool	wake_by_pcie;
>   	u32	lanes;
>   	u8	root_bus_nr;
>   	int	link_gen;
> @@ -853,6 +856,20 @@ static void rockchip_pcie_legacy_int_handler(struct irq_desc *desc)
>   	chained_irq_exit(chip, desc);
>   }
>   
> +static irqreturn_t rockchip_pcie_wake_irq_handler(int irq, void *arg)
> +{
> +	struct rockchip_pcie *rockchip = arg;
> +
> +	rockchip->wake_by_pcie = true;
> +
> +	disable_irq_nosync(rockchip->wake_irq);
> +	disable_irq_wake(rockchip->wake_irq);
> +
> +	pm_wakeup_event(rockchip->dev, 0);
> +	pm_system_wakeup();
> +
> +	return IRQ_HANDLED;
> +}
>   
>   /**
>    * rockchip_pcie_parse_dt - Parse Device Tree
> @@ -868,6 +885,7 @@ static int rockchip_pcie_parse_dt(struct rockchip_pcie *rockchip)
>   	struct resource *regs;
>   	int irq;
>   	int err;
> +	bool wakeup = 0;
>   
>   	regs = platform_get_resource_byname(pdev,
>   					    IORESOURCE_MEM,
> @@ -1018,6 +1036,21 @@ static int rockchip_pcie_parse_dt(struct rockchip_pcie *rockchip)
>   		return err;
>   	}
>   
> +	rockchip->wake_irq = platform_get_irq_byname(pdev, "wake");
> +	if (rockchip->wake_irq >= 0) {
> +		err = devm_request_irq(dev, rockchip->wake_irq,
> +				       rockchip_pcie_wake_irq_handler,
> +				       0, "pcie-wake", rockchip);
> +		if (err) {
> +			dev_err(dev, "failed to request PCIe wake IRQ\n");
> +			return err;

This is optional, so I'm not sure if we should prevent the driver to
probe?

> +		}
> +
> +		disable_irq(rockchip->wake_irq);
> +		wakeup = device_property_read_bool(dev, "wakeup-source");

The purpose we add this, is for ep to wakeup the system, so why not
always treate it as a wakeup source.

> +	}
> +	device_init_wakeup(dev, wakeup);
> +
>   	rockchip->vpcie3v3 = devm_regulator_get_optional(dev, "vpcie3v3");
>   	if (IS_ERR(rockchip->vpcie3v3)) {
>   		if (PTR_ERR(rockchip->vpcie3v3) == -EPROBE_DEFER)
> @@ -1270,6 +1303,30 @@ static int rockchip_pcie_wait_l2(struct rockchip_pcie *rockchip)
>   	return 0;
>   }
>   
> +static int __maybe_unused rockchip_pcie_suspend(struct device *dev)
> +{
> +	struct rockchip_pcie *rockchip = dev_get_drvdata(dev);
> +
> +	rockchip->wake_by_pcie = false;
> +
> +	if (device_may_wakeup(dev)) {
> +		enable_irq_wake(rockchip->wake_irq);
> +		enable_irq(rockchip->wake_irq);
> +	}
> +	return 0;
> +}
> +
> +static int __maybe_unused rockchip_pcie_resume(struct device *dev)
> +{
> +	struct rockchip_pcie *rockchip = dev_get_drvdata(dev);
> +
> +	if (device_may_wakeup(dev) && !rockchip->wake_by_pcie) {

I don't get this that why we need to check wake_by_pcie here?

> +		disable_irq(rockchip->wake_irq);
> +		disable_irq_wake(rockchip->wake_irq);
> +	}
> +	return 0;
> +}
> +
>   static int __maybe_unused rockchip_pcie_suspend_noirq(struct device *dev)
>   {
>   	struct rockchip_pcie *rockchip = dev_get_drvdata(dev);
> @@ -1548,6 +1605,7 @@ static int rockchip_pcie_remove(struct platform_device *pdev)
>   }
>   
>   static const struct dev_pm_ops rockchip_pcie_pm_ops = {
> +	SET_SYSTEM_SLEEP_PM_OPS(rockchip_pcie_suspend, rockchip_pcie_resume)
>   	SET_NOIRQ_SYSTEM_SLEEP_PM_OPS(rockchip_pcie_suspend_noirq,
>   				      rockchip_pcie_resume_noirq)
>   };
>