Re: [RFC PATCH v12 4/5] PCI / PM: Add support for the PCIe WAKE# signal for OF

[Rob Herring <robh@kernel.org>]

On Tue, Dec 26, 2017 at 10:36:45AM +0800, Jeffy Chen wrote:
> Add of_pci_setup_wake_irq() and of_pci_teardown_wake_irq() to handle
> the PCIe WAKE# interrupt.
> 
> Also use the dedicated wakeirq infrastructure to simplify it.
> 
> And add pci-of.c to enable/disable the wakeup irq in noirq stage to
> avoid possible irq storm.
> 
> Signed-off-by: Jeffy Chen <jeffy.chen@rock-chips.com>
> ---
> 
> Changes in v13:
> Fix compiler error reported by kbuild test robot <fengguang.wu@intel.com>
> 
> Changes in v12:
> Enable the wake irq in noirq stage to avoid possible irq storm.
> 
> Changes in v11:
> Only support 1-per-device PCIe WAKE# pin as suggested.
> 
> Changes in v10:
> Use device_set_wakeup_capable() instead of device_set_wakeup_enable(),
> since dedicated wakeirq will be lost in device_set_wakeup_enable(false).
> 
> Changes in v9:
> Fix check error in .cleanup().
> Move dedicated wakeirq setup to setup() callback and use
> device_set_wakeup_enable() to enable/disable.
> 
> Changes in v8:
> Add pci-of.c and use platform_pm_ops to handle the PCIe WAKE# signal.
> 
> Changes in v7:
> Move PCIE_WAKE handling into pci core.
> 
> Changes in v6:
> Fix device_init_wake error handling, and add some comments.
> 
> Changes in v5:
> Rebase.
> 
> Changes in v3:
> Fix error handling.
> 
> Changes in v2:
> Use dev_pm_set_dedicated_wake_irq.
> 
>  drivers/of/of_pci_irq.c  | 49 +++++++++++++++++++++++++++++++

Please move this to drivers/pci/of.c (or perhaps create pci/of_irq.c).

>  drivers/pci/Makefile     |  1 +
>  drivers/pci/pci-driver.c | 10 +++++++
>  drivers/pci/pci-of.c     | 75 ++++++++++++++++++++++++++++++++++++++++++++++++

We already have drivers/pci/of.c. It's not clear what the difference is 
from the filenames. Either merge with of.c or perhaps of-pm.c.

>  include/linux/of_pci.h   |  9 ++++++
>  5 files changed, 144 insertions(+)
>  create mode 100644 drivers/pci/pci-of.c
> 
> diff --git a/drivers/of/of_pci_irq.c b/drivers/of/of_pci_irq.c
> index d39565d5477b..abec3a44853b 100644
> --- a/drivers/of/of_pci_irq.c
> +++ b/drivers/of/of_pci_irq.c
> @@ -1,8 +1,57 @@
>  #include <linux/kernel.h>
>  #include <linux/of_pci.h>
>  #include <linux/of_irq.h>
> +#include <linux/pm_wakeirq.h>
>  #include <linux/export.h>
>  
> +int of_pci_setup_wake_irq(struct pci_dev *pdev)
> +{
> +	struct pci_dev *ppdev;
> +	struct device_node *dn;
> +	int ret, irq;
> +
> +	/* Get the pci_dev of our parent. Hopefully it's a port. */
> +	ppdev = pdev->bus->self;
> +	/* Nope, it's a host bridge. */
> +	if (!ppdev)
> +		return 0;
> +
> +	dn = pci_device_to_OF_node(ppdev);
> +	if (!dn)
> +		return 0;
> +
> +	irq = of_irq_get_byname(dn, "wakeup");
> +	if (irq == -EPROBE_DEFER) {
> +		return irq;
> +	} else if (irq < 0) {
> +		/* Ignore other errors, since a missing wakeup is non-fatal. */
> +		dev_info(&pdev->dev, "cannot get wakeup interrupt: %d\n", irq);
> +		return 0;
> +	}
> +
> +	device_init_wakeup(&pdev->dev, true);
> +
> +	ret = dev_pm_set_dedicated_wake_irq(&pdev->dev, irq);
> +	if (ret < 0) {
> +		dev_err(&pdev->dev, "failed to set wake IRQ: %d\n", ret);
> +		device_init_wakeup(&pdev->dev, false);
> +		return ret;
> +	}
> +
> +	/* Start out disabled to avoid irq storm */
> +	dev_pm_disable_wake_irq(&pdev->dev);
> +
> +	return 0;
> +}
> +EXPORT_SYMBOL_GPL(of_pci_setup_wake_irq);
> +
> +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);
> +
>  /**
>   * of_irq_parse_pci - Resolve the interrupt for a PCI device
>   * @pdev:       the device whose interrupt is to be resolved
> diff --git a/drivers/pci/Makefile b/drivers/pci/Makefile
> index c7819b973df7..d0182c82162a 100644
> --- a/drivers/pci/Makefile
> +++ b/drivers/pci/Makefile
> @@ -29,6 +29,7 @@ obj-$(CONFIG_PCI_IOV) += iov.o
>  # ACPI _DSM provided firmware instance and string name
>  #
>  obj-$(CONFIG_ACPI)    += pci-acpi.o
> +obj-$(CONFIG_OF)      += pci-of.o
>  
>  # SMBIOS provided firmware instance and labels
>  obj-$(CONFIG_PCI_LABEL) += pci-label.o
> diff --git a/drivers/pci/pci-driver.c b/drivers/pci/pci-driver.c
> index d79dbc377b9c..b4475ff35d97 100644
> --- a/drivers/pci/pci-driver.c
> +++ b/drivers/pci/pci-driver.c
> @@ -17,6 +17,7 @@
>  #include <linux/slab.h>
>  #include <linux/sched.h>
>  #include <linux/cpu.h>
> +#include <linux/of_pci.h>
>  #include <linux/pm_runtime.h>
>  #include <linux/suspend.h>
>  #include <linux/kexec.h>
> @@ -421,10 +422,17 @@ static int pci_device_probe(struct device *dev)
>  	if (error < 0)
>  		return error;
>  
> +	error = of_pci_setup_wake_irq(pci_dev);
> +	if (error < 0) {
> +		pcibios_free_irq(pci_dev);
> +		return error;
> +	}
> +
>  	pci_dev_get(pci_dev);
>  	if (pci_device_can_probe(pci_dev)) {
>  		error = __pci_device_probe(drv, pci_dev);
>  		if (error) {
> +			of_pci_teardown_wake_irq(pci_dev);
>  			pcibios_free_irq(pci_dev);
>  			pci_dev_put(pci_dev);
>  		}
> @@ -438,6 +446,8 @@ static int pci_device_remove(struct device *dev)
>  	struct pci_dev *pci_dev = to_pci_dev(dev);
>  	struct pci_driver *drv = pci_dev->driver;
>  
> +	of_pci_teardown_wake_irq(pci_dev);
> +
>  	if (drv) {
>  		if (drv->remove) {
>  			pm_runtime_get_sync(dev);
> diff --git a/drivers/pci/pci-of.c b/drivers/pci/pci-of.c
> new file mode 100644
> index 000000000000..ad413b2de508
> --- /dev/null
> +++ b/drivers/pci/pci-of.c
> @@ -0,0 +1,75 @@
> +/*
> + * File:	pci-of.c
> + * Purpose:	Provide PCI PM/wakeup support in OF systems
> + *
> + * Copyright (C) 2017 Google, Inc.
> + *	Brian Norris <briannorris@chromium.org>
> + *
> + * Copyright (C) 2017 Rockchip Electronics Co., Ltd.
> + *	Jeffy Chen <jeffy.chen@rock-chips.com>
> + *
> + * This program is free software; you can redistribute it and/or modify it
> + * under the terms and conditions of the GNU General Public License,
> + * version 2, as published by the Free Software Foundation.
> + */
> +
> +#include <linux/acpi.h>
> +#include <linux/init.h>
> +#include <linux/module.h>
> +#include <linux/pci.h>
> +#include <linux/pm_wakeirq.h>
> +#include "pci.h"
> +
> +static bool of_pci_power_manageable(struct pci_dev *dev)
> +{
> +	return false;
> +}
> +
> +static int of_pci_set_power_state(struct pci_dev *dev, pci_power_t state)
> +{
> +	return -ENOSYS;
> +}
> +
> +static pci_power_t of_pci_get_power_state(struct pci_dev *dev)
> +{
> +	return PCI_UNKNOWN;
> +}
> +
> +static pci_power_t of_pci_choose_state(struct pci_dev *pdev)
> +{
> +	return PCI_POWER_ERROR;
> +}
> +
> +static int of_pci_wakeup(struct pci_dev *dev, bool enable)
> +{
> +	if (enable)
> +		dev_pm_enable_wake_irq(&dev->dev);
> +	else
> +		dev_pm_disable_wake_irq(&dev->dev);
> +	return 0;
> +}
> +
> +static bool of_pci_need_resume(struct pci_dev *dev)
> +{
> +	return false;
> +}
> +
> +static const struct pci_platform_pm_ops of_pci_platform_pm = {
> +	.is_manageable = of_pci_power_manageable,
> +	.set_state = of_pci_set_power_state,
> +	.get_state = of_pci_get_power_state,
> +	.choose_state = of_pci_choose_state,
> +	.set_wakeup = of_pci_wakeup,
> +	.need_resume = of_pci_need_resume,
> +};
> +
> +static int __init of_pci_init(void)
> +{
> +	if (!acpi_disabled)
> +		return 0;
> +
> +	pci_set_platform_pm(&of_pci_platform_pm);

I guess no DT based system will override this?

> +
> +	return 0;
> +}
> +arch_initcall(of_pci_init);