Re: [PATCH V3 20/21] pci, acpi: Match PCI config space accessors against platfrom specific quirks.

[liudongdong (C)]

Hi Tomasz, Mark

å 2016/1/18 20:41, Tomasz Nowicki åé:
> On 14.01.2016 16:36, Mark Salter wrote:
> > > +extern struct pci_mcfg_fixup __start_acpi_mcfg_fixups[];
> > > >+extern struct pci_mcfg_fixup __end_acpi_mcfg_fixups[];
> > > >+
> > > >+static struct pci_ops *pci_mcfg_check_quirks(struct acpi_pci_root *root)
> > > >+{
> > > >+    struct pci_mcfg_fixup *f;
> > > >+    int bus_num = root->secondary.start;
> > > >+    int domain = root->segment;
> > > >+
> > > >+    /*
> > > >+     * First match against PCI topology <domain:bus> then use DMI or
> > > >+     * custom match handler.
> > > >+     */
> > > >+    for (f = __start_acpi_mcfg_fixups; f < __end_acpi_mcfg_fixups; f++) {
> > > >+        if ((f->domain == domain || f->domain == PCI_MCFG_DOMAIN_ANY) &&
> > > >+            (f->bus_num == bus_num || f->bus_num == PCI_MCFG_BUS_ANY) &&
> > > >+            (f->system ? dmi_check_system(f->system) : 0 ||
> > > >+             f->match ? f->match(f, root) : 0))
> > > >+            return f->ops;
> > I think this would be better as:
> >
> >             (f->system ? dmi_check_system(f->system) : 1 &&
> >              f->match ? f->match(f, root) : 1))
> >             return f->ops;
> >
> > Otherwise, one has to call dmi_check_system() from f->match() if
> > access to root is needed.

Non-DMI, we need not to call dmi_check_system() from f->match(),
we can use _HID to decide to hook the pci_ops or not.

Device (PCI1)
{
        Name (_HID, "HISI0080") // PCI Express Root Bridge
        Name (_CID, "PNP0A03") // Compatible PCI Root Bridge
	...
}

static const struct acpi_device_id hisi_pcie_ids[] = {
    {"HISI0080", 0},
    {"", 0},
};

static int hisi_pcie_match(struct pci_mcfg_fixup *fixup, struct acpi_pci_root *root)
{
    int ret;
    struct acpi_device *device;

    device = root->device;
    ret = acpi_match_device_ids(device, hisi_pcie_ids);
    if (ret)
        return 0;
    ......
    return 1;
}

static struct pci_ops hisi_ecam_pci_ops = {
    .map_bus = pci_mcfg_dev_base,
    .read = hisi_pci_read,
    .write = hisi_pci_write,
};

DECLARE_ACPI_MCFG_FIXUP(NULL, hisi_pcie_match, &hisi_ecam_pci_ops,
    PCI_MCFG_DOMAIN_ANY, PCI_MCFG_BUS_ANY);

Thanks
Dongdong
> Makes a lot of sense to me, I will modify as you suggested.
>
> Tomasz
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