Re: [PATCH v2 2/2] PCI: Add support for PCIe wake interrupt

[Krishna Chaitanya Chundru <krishna.chundru@oss.qualcomm.com>]

On 5/15/2025 11:59 AM, Sherry Sun wrote:
> 
> 
>> -----Original Message-----
>> From: Krishna Chaitanya Chundru <krishna.chundru@oss.qualcomm.com>
>> Sent: Friday, May 9, 2025 3:59 PM
>> To: Bjorn Helgaas <bhelgaas@google.com>
>> Cc: linux-arm-msm@vger.kernel.org; Konrad Dybcio
>> <konradybcio@kernel.org>; devicetree@vger.kernel.org; linux-
>> kernel@vger.kernel.org; linux-pci@vger.kernel.org;
>> quic_vbadigan@quicinc.com; quic_mrana@quicinc.com; cros-qcom-dts-
>> watchers@chromium.org; Conor Dooley <conor+dt@kernel.org>; Rob Herring
>> <robh@kernel.org>; Krzysztof Kozlowski <krzk+dt@kernel.org>; Bjorn
>> Andersson <andersson@kernel.org>
>> Subject: Re: [PATCH v2 2/2] PCI: Add support for PCIe wake interrupt
>>
>> A Gentle remainder.
>>
>> - Krishna Chaitanya.
>>
>> On 4/19/2025 11:13 AM, Krishna Chaitanya Chundru wrote:
>>> PCIe wake interrupt is needed for bringing back PCIe device state from
>>> D3cold to D0.
>>>
>>> Implement new functions, of_pci_setup_wake_irq() and
>>> of_pci_teardown_wake_irq(), to manage wake interrupts for PCI devices
>>> using the Device Tree.
>>>
>>>   From the port bus driver call these functions to enable wake support
>>> for bridges.
>>>
>>> Signed-off-by: Krishna Chaitanya Chundru
>>> <krishna.chundru@oss.qualcomm.com>
> 
> Hi Krishna,
> 
> I have tested the patch set on i.MX platforms, it works.
> you can add my Tested-by: Sherry Sun <sherry.sun@nxp.com>.
> 
> BTW, as PEWAKE is a standard feature in PCIe bus specification,
> Suppose you may need to add wake-gpios property into the common
> PCI root port dt-schema.
> 
I raised a patch for this:
https://lore.kernel.org/all/20250515090517.3506772-1-krishna.chundru@oss.qualcomm.com/

- Krishna Chaitanya.
> Best Regards
> Sherry
> 
>>> ---
>>>    drivers/pci/of.c           | 60
>> ++++++++++++++++++++++++++++++++++++++++++++++
>>>    drivers/pci/pci.h          |  6 +++++
>>>    drivers/pci/pcie/portdrv.c | 12 +++++++++-
>>>    3 files changed, 77 insertions(+), 1 deletion(-)
>>>
>>> diff --git a/drivers/pci/of.c b/drivers/pci/of.c index
>>>
>> ab7a8252bf4137a17971c3eb8ab70ce78ca70969..13623797c88a03dfb9d90795
>> 18d8
>>> 7a5e1e68df38 100644
>>> --- a/drivers/pci/of.c
>>> +++ b/drivers/pci/of.c
>>> @@ -7,6 +7,7 @@
>>>    #define pr_fmt(fmt)	"PCI: OF: " fmt
>>>
>>>    #include <linux/cleanup.h>
>>> +#include <linux/gpio/consumer.h>
>>>    #include <linux/irqdomain.h>
>>>    #include <linux/kernel.h>
>>>    #include <linux/pci.h>
>>> @@ -15,6 +16,7 @@
>>>    #include <linux/of_address.h>
>>>    #include <linux/of_pci.h>
>>>    #include <linux/platform_device.h>
>>> +#include <linux/pm_wakeirq.h>
>>>    #include "pci.h"
>>>
>>>    #ifdef CONFIG_PCI
>>> @@ -966,3 +968,61 @@ u32 of_pci_get_slot_power_limit(struct
>> device_node *node,
>>>    	return slot_power_limit_mw;
>>>    }
>>>    EXPORT_SYMBOL_GPL(of_pci_get_slot_power_limit);
>>> +
>>> +/**
>>> + * of_pci_setup_wake_irq - Set up wake interrupt for PCI device
>>> + * @pdev: The PCI device structure
>>> + *
>>> + * This function sets up the wake interrupt for a PCI device by
>>> +getting the
>>> + * corresponding GPIO pin from the device tree, and configuring it as
>>> +a
>>> + * dedicated wake interrupt.
>>> + *
>>> + * Return: 0 if the wake gpio is not available or successfully parsed
>>> +else
>>> + * errno otherwise.
>>> + */
>>> +int of_pci_setup_wake_irq(struct pci_dev *pdev) {
>>> +	struct gpio_desc *wake;
>>> +	struct device_node *dn;
>>> +	int ret, wake_irq;
>>> +
>>> +	dn = pci_device_to_OF_node(pdev);
>>> +	if (!dn)
>>> +		return 0;
>>> +
>>> +	wake = devm_fwnode_gpiod_get(&pdev->dev,
>> of_fwnode_handle(dn),
>>> +				     "wake", GPIOD_IN, NULL);
>>> +	if (IS_ERR(wake)) {
>>> +		dev_warn(&pdev->dev, "Cannot get wake GPIO\n");
>>> +		return 0;
>>> +	}
>>> +
>>> +	wake_irq = gpiod_to_irq(wake);
>>> +	device_init_wakeup(&pdev->dev, true);
>>> +
>>> +	ret = dev_pm_set_dedicated_wake_irq(&pdev->dev, wake_irq);
>>> +	if (ret < 0) {
>>> +		dev_err(&pdev->dev, "Failed to set wake IRQ: %d\n", ret);
>>> +		device_init_wakeup(&pdev->dev, false);
>>> +		return ret;
>>> +	}
>>> +	irq_set_irq_type(wake_irq, IRQ_TYPE_EDGE_FALLING);
>>> +
>>> +	return 0;
>>> +}
>>> +EXPORT_SYMBOL_GPL(of_pci_setup_wake_irq);
>>> +
>>> +/**
>>> + * of_pci_teardown_wake_irq - Teardown wake interrupt setup for PCI
>>> +device
>>> + *
>>> + * @pdev: The PCI device structure
>>> + *
>>> + * This function tears down the wake interrupt setup for a PCI
>>> +device,
>>> + * clearing the dedicated wake interrupt and disabling device wake-up.
>>> + */
>>> +void of_pci_teardown_wake_irq(struct pci_dev *pdev) {
>>> +	dev_pm_clear_wake_irq(&pdev->dev);
>>> +	device_init_wakeup(&pdev->dev, false); }
>>> +EXPORT_SYMBOL_GPL(of_pci_teardown_wake_irq);
>>> diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h index
>>>
>> b81e99cd4b62a3022c8b07a09f212f6888674487..b2f65289f4156fa1851c2d2f2
>> 0c4
>>> ca948f36258f 100644
>>> --- a/drivers/pci/pci.h
>>> +++ b/drivers/pci/pci.h
>>> @@ -888,6 +888,9 @@ void pci_release_of_node(struct pci_dev *dev);
>>>    void pci_set_bus_of_node(struct pci_bus *bus);
>>>    void pci_release_bus_of_node(struct pci_bus *bus);
>>>
>>> +int of_pci_setup_wake_irq(struct pci_dev *pdev); void
>>> +of_pci_teardown_wake_irq(struct pci_dev *pdev);
>>> +
>>>    int devm_of_pci_bridge_init(struct device *dev, struct pci_host_bridge
>> *bridge);
>>>    bool of_pci_supply_present(struct device_node *np);
>>>
>>> @@ -931,6 +934,9 @@ static inline int devm_of_pci_bridge_init(struct
>> device *dev, struct pci_host_br
>>>    	return 0;
>>>    }
>>>
>>> +static int of_pci_setup_wake_irq(struct pci_dev *pdev) { return 0; }
>>> +static void of_pci_teardown_wake_irq(struct pci_dev *pdev) { }
>>> +
>>>    static inline bool of_pci_supply_present(struct device_node *np)
>>>    {
>>>    	return false;
>>> diff --git a/drivers/pci/pcie/portdrv.c b/drivers/pci/pcie/portdrv.c
>>> index
>>>
>> e8318fd5f6ed537a1b236a3a0f054161d5710abd..33220ecf821c348d49782855
>> eb5a
>>> a3f2fe5c335e 100644
>>> --- a/drivers/pci/pcie/portdrv.c
>>> +++ b/drivers/pci/pcie/portdrv.c
>>> @@ -694,12 +694,18 @@ static int pcie_portdrv_probe(struct pci_dev *dev,
>>>    	     (type != PCI_EXP_TYPE_RC_EC)))
>>>    		return -ENODEV;
>>>
>>> +	status = of_pci_setup_wake_irq(dev);
>>> +	if (status)
>>> +		return status;
>>> +
>>>    	if (type == PCI_EXP_TYPE_RC_EC)
>>>    		pcie_link_rcec(dev);
>>>
>>>    	status = pcie_port_device_register(dev);
>>> -	if (status)
>>> +	if (status) {
>>> +		of_pci_teardown_wake_irq(dev);
>>>    		return status;
>>> +	}
>>>
>>>    	pci_save_state(dev);
>>>
>>> @@ -732,6 +738,8 @@ static void pcie_portdrv_remove(struct pci_dev
>>> *dev)
>>>
>>>    	pcie_port_device_remove(dev);
>>>
>>> +	of_pci_teardown_wake_irq(dev);
>>> +
>>>    	pci_disable_device(dev);
>>>    }
>>>
>>> @@ -744,6 +752,8 @@ static void pcie_portdrv_shutdown(struct pci_dev
>> *dev)
>>>    	}
>>>
>>>    	pcie_port_device_remove(dev);
>>> +
>>> +	of_pci_teardown_wake_irq(dev);
>>>    }
>>>
>>>    static pci_ers_result_t pcie_portdrv_error_detected(struct pci_dev
>>> *dev,
>>>
>