Re: [PATCH 1/5 V2] PCI: define a function to check and wait till port finish DPC handling

[Ethan Zhao]

Fixed this concern by moving the function to DPC driver and its
declaration to pci.h.  see v5

Thanks,
Ethan

On Sun, Sep 27, 2020 at 2:27 PM Christoph Hellwig <hch@xxxxxxxxxxxxx> wrote:
>
> > +#ifdef CONFIG_PCIE_DPC
> > +static inline bool pci_wait_port_outdpc(struct pci_dev *pdev)
> > +{
> > +     u16 cap = pdev->dpc_cap, status;
> > +     u16 loop = 0;
> > +
> > +     if (!cap) {
> > +             pci_WARN_ONCE(pdev, !cap, "No DPC capability initiated\n");
> > +             return false;
> > +     }
> > +     pci_read_config_word(pdev, cap + PCI_EXP_DPC_STATUS, &status);
> > +     pci_dbg(pdev, "DPC status %x, cap %x\n", status, cap);
> > +     while (status & PCI_EXP_DPC_STATUS_TRIGGER && loop < 100) {
> > +             msleep(10);
> > +             loop++;
> > +             pci_read_config_word(pdev, cap + PCI_EXP_DPC_STATUS, &status);
> > +     }
> > +     if (!(status & PCI_EXP_DPC_STATUS_TRIGGER)) {
> > +             pci_dbg(pdev, "Out of DPC %x, cost %d ms\n", status, loop*10);
> > +             return true;
> > +     }
> > +     pci_dbg(pdev, "Timeout to wait port out of DPC status\n");
> > +     return false;
> > +}
>
> I don't think that there is any good reason to have this as an
> inline function.