Re: [PATCH v11 6/7] PCI: Unify wait for link active into generic pci

[poza]

On 2018-02-24 21:11, Bjorn Helgaas wrote:
> In subject:
>
> s/pci/PCI/
sure.
> On Fri, Feb 23, 2018 at 01:54:03PM +0530, Oza Pawandeep wrote:
> > Clients such as pciehp, dpc are using pcie_wait_link_active, which 
> > waits
> > till the link becomes active or inactive.
>
> Use "()" after function names so we have a visual clue that they are
> functions.
>
> > Made generic function and moved it to drivers/pci/pci.c
> >
> > Signed-off-by: Oza Pawandeep <poza@xxxxxxxxxxxxxx>
> >
> > diff --git a/drivers/pci/hotplug/pciehp_hpc.c 
> > b/drivers/pci/hotplug/pciehp_hpc.c
> > index 18a42f8..de9b0ea 100644
> > --- a/drivers/pci/hotplug/pciehp_hpc.c
> > +++ b/drivers/pci/hotplug/pciehp_hpc.c
> > @@ -231,25 +231,11 @@ bool pciehp_check_link_active(struct controller 
> > *ctrl)
> >  	return ret;
> >  }
> >
> > -static void __pcie_wait_link_active(struct controller *ctrl, bool 
> > active)
> > +static bool pcie_wait_link_active(struct controller *ctrl)
> >  {
> > -	int timeout = 1000;
> > -
> > -	if (pciehp_check_link_active(ctrl) == active)
> > -		return;
> > -	while (timeout > 0) {
> > -		msleep(10);
> > -		timeout -= 10;
> > -		if (pciehp_check_link_active(ctrl) == active)
> > -			return;
> > -	}
> > -	ctrl_dbg(ctrl, "Data Link Layer Link Active not %s in 1000 msec\n",
> > -			active ? "set" : "cleared");
> > -}
> > +	struct pci_dev *pdev = ctrl_dev(ctrl);
> >
> > -static void pcie_wait_link_active(struct controller *ctrl)
> > -{
> > -	__pcie_wait_link_active(ctrl, true);
> > +	return pci_wait_for_link(pdev, true);
> >  }
> >
> >  static bool pci_bus_check_dev(struct pci_bus *bus, int devfn)
> > diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
> > index f6a4dd1..f8d44b4 100644
> > --- a/drivers/pci/pci.c
> > +++ b/drivers/pci/pci.c
> > @@ -4176,6 +4176,37 @@ static int pci_pm_reset(struct pci_dev *dev, 
> > int probe)
> >  	return 0;
> >  }
> >
> > +/**
> > + * pci_wait_for_link - Wait for link till its active/inactive
>
> s/its/it's/
sure.
> > + * @pdev: Bridge device
> > + * @active: waiting for active or inactive ?
> > + *
> > + * Use this to wait till link becomes active or inactive.
> > + */
> > +bool pci_wait_for_link(struct pci_dev *pdev, bool active)
>
> I think this should be "pcie_wait_for_link()".  There's no concept of a
> link in conventional PCI.
>
> > +{
> > +	int timeout = 1000;
> > +	bool ret;
> > +	u16 lnk_status;
> > +
> > +	for (;;) {
> > +		pcie_capability_read_word(pdev, PCI_EXP_LNKSTA, &lnk_status);
> > +		ret = !!(lnk_status & PCI_EXP_LNKSTA_DLLLA);
> > +		if (ret == active)
> > +			return true;
> > +		if (timeout <= 0)
> > +			break;
> > +		timeout -= 10;
> > +	}
> > +
> > +	dev_printk(KERN_DEBUG, &pdev->dev,
>
> pci_info().  Distros often seem to have logging configured so
> KERN_DEBUG things aren't captured, and this definitely seems worth
> capturing.
>
> > +		   "Data Link Layer Link Active not %s in 1000 msec\n",
> > +		   active ? "set" : "cleared");
> > +
> > +	return false;
> > +}
> > +EXPORT_SYMBOL(pci_wait_for_link);
>
> I don't think this needs to be exported.
sure.
> >  void pci_reset_secondary_bus(struct pci_dev *dev)
> >  {
> >  	u16 ctrl;
> > diff --git a/drivers/pci/pcie/pcie-dpc.c b/drivers/pci/pcie/pcie-dpc.c
> > index 5c01c63..e15bcda 100644
> > --- a/drivers/pci/pcie/pcie-dpc.c
> > +++ b/drivers/pci/pcie/pcie-dpc.c
> > @@ -120,19 +120,9 @@ static int dpc_wait_rp_inactive(struct dpc_dev 
> > *dpc)
> >
> >  static void dpc_wait_link_inactive(struct dpc_dev *dpc)
> >  {
> > -	unsigned long timeout = jiffies + HZ;
> >  	struct pci_dev *pdev = dpc->dev->port;
> > -	struct device *dev = &dpc->dev->device;
> > -	u16 lnk_status;
> >
> > -	pcie_capability_read_word(pdev, PCI_EXP_LNKSTA, &lnk_status);
> > -	while (lnk_status & PCI_EXP_LNKSTA_DLLLA &&
> > -					!time_after(jiffies, timeout)) {
> > -		msleep(10);
> > -		pcie_capability_read_word(pdev, PCI_EXP_LNKSTA, &lnk_status);
> > -	}
> > -	if (lnk_status & PCI_EXP_LNKSTA_DLLLA)
> > -		dev_warn(dev, "Link state not disabled for DPC event\n");
> > +	pci_wait_for_link(pdev, false);
> >  }
> >
> >  /**
> > diff --git a/include/linux/pci.h b/include/linux/pci.h
> > index 024a1be..cb674c3 100644
> > --- a/include/linux/pci.h
> > +++ b/include/linux/pci.h
> > @@ -1195,6 +1195,7 @@ int pci_add_ext_cap_save_buffer(struct pci_dev 
> > *dev,
> >  int pci_request_selected_regions(struct pci_dev *, int, const char 
> > *);
> >  int pci_request_selected_regions_exclusive(struct pci_dev *, int, 
> > const char *);
> >  void pci_release_selected_regions(struct pci_dev *, int);
> > +bool pci_wait_for_link(struct pci_dev *pdev, bool active);
>
> I don't think this needs to be available outside the PCI core, so this
> could probably be declared in drivers/pci/pci.h

thanks, will move it.

> >  /* drivers/pci/bus.c */
> >  struct pci_bus *pci_bus_get(struct pci_bus *bus);
> > --
> > Qualcomm Datacenter Technologies, Inc. as an affiliate of Qualcomm 
> > Technologies, Inc.,
> > a Qualcomm Technologies, Inc. is a member of the Code Aurora Forum, a 
> > Linux Foundation Collaborative Project.