Re: [RFC,v14 3/5] PCI / PM: Add support for the PCIe WAKE# signal for OF

[Manikanta Maddireddy]

On 2/8/2023 5:20 PM, Thierry Reding wrote:
> On Wed, Feb 08, 2023 at 04:46:43PM +0530, Manikanta Maddireddy wrote:
> > From: Jeffy Chen <jeffy.chen@xxxxxxxxxxxxxx>
> >
> > Add of_pci_setup_wake_irq() to parse the PCIe WAKE# interrupt from the
> > device tree and set the wake irq. Add of_pci_teardown_wake_irq() to clear
> > the wake irq.
> >
> > Call of_pci_setup_wake_irq() in pci_device_probe() to setup PCIe WAKE#
> > interrupt during PCIe Endpoint enumeration.
> >
> > Enable or disable PCIe WAKE# interrupt in platform_pci_set_wakeup().
> >
> > Signed-off-by: Jeffy Chen <jeffy.chen@xxxxxxxxxxxxxx>
> > Signed-off-by: Manikanta Maddireddy <mmaddireddy@xxxxxxxxxx>
> > ---
> >
> > Changes in v14:
> > pci_platform_pm_ops structure is removed in latest kernel, so dropped
> > pci-of driver. Instead, enable wake in platform_pci_set_wakeup().
> >
> > Changes in v13:
> > Fix compiler error reported by kbuild test robot <fengguang.wu@xxxxxxxxx>
> >
> > 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/pci/of.c         | 49 ++++++++++++++++++++++++++++++++++++++++
> >   drivers/pci/pci-driver.c | 10 ++++++++
> >   drivers/pci/pci.c        |  7 ++++++
> >   drivers/pci/pci.h        |  8 +++++++
> >   4 files changed, 74 insertions(+)
> >
> > diff --git a/drivers/pci/of.c b/drivers/pci/of.c
> > index ff897c40ed71..1c348e63f175 100644
> > --- a/drivers/pci/of.c
> > +++ b/drivers/pci/of.c
> > @@ -13,6 +13,7 @@
> >   #include <linux/of_irq.h>
> >   #include <linux/of_address.h>
> >   #include <linux/of_pci.h>
> > +#include <linux/pm_wakeirq.h>
> >   #include "pci.h"
> >   
> >   #ifdef CONFIG_PCI
> > @@ -705,3 +706,51 @@ 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);
> > +
> > +int of_pci_setup_wake_irq(struct pci_dev *pdev)
> > +{
> > +	struct pci_dev *ppdev;
> Perhaps "parent" since that's what it is referring to? ppdev is a bit
> vague.
ppdev is already used in of_irq_parse_pci(), I think it mean parent pci_dev.
I see that parent is mostly used for pci_bus parent. Let me know if it 
is fine
to leave it as ppdev or need to rename it.
> > +	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);
> dev_dbg() maybe? As it is this would add an annoying info message for
> basically every PCI controller on every DT-based board out there.
>
> Thierry
Ack. I will wait for few days for other review this series before 
sending new patch set.

Manikanta