Re: [PATCH v3] PCI: loongson: Use DECLARE_PCI_FIXUP_EARLY for bridge_class_quirk()

[Tiezhu Yang]

On 07/16/2020 10:21 AM, Huacai Chen wrote:
> Hi, Tiezhu,
>
> You don't need to use the lower case in the title, "Loongson" is just
> fine (and is recommended).

Hi Huacai,

Thanks for your reply.

In the first version of this patch, I received the following reply by Bjorn:

[Subject line:

  PCI: loongson: Use DECLARE_PCI_FIXUP_EARLY for bridge_class_quirk()

(Driver names are conventionally lower case.)

Lorenzo will probably silently fix this when applying, so this is
mostly just a reminder in case you need to revise this or for future
patches.]

https://lore.kernel.org/patchwork/patch/1254407/

I also checked the git log of drivers/pci/controller:

[yangtiezhu@linux linux.git]$ git log --oneline drivers/pci/controller | 
grep "PCI:" | head
8d7e33d PCI: uniphier: Add Socionext UniPhier Pro5 PCIe endpoint 
controller driver
fcee90c PCI: tegra: Fix runtime PM imbalance on error
3e5095e PCI: vmd: Filter resource type bits from shadow register
1c1dbb2 PCI: tegra194: Fix runtime PM imbalance on error
d0684fd0 PCI: hv: Use struct_size() helper
1f58cca PCI: Add Loongson PCI Controller support
03f8c1b3 PCI: dwc: Use private data pointer of "struct irq_domain" to 
get pcie_port
87dccf0 PCI: amlogic: meson: Don't use FAST_LINK_MODE to set up link
0414b93 PCI: dwc: Fix inner MSI IRQ domain registration
c8a1197 PCI: dwc: pci-dra7xx: Use devm_platform_ioremap_resource_byname()

So use lower case "loongson" may be proper here.

Thanks,
Tiezhu

> On Thu, Jul 16, 2020 at 10:19 AM Tiezhu Yang <yangtiezhu@xxxxxxxxxxx> wrote:
> > According to the datasheet of Loongson LS7A bridge chip, the old version
> > of Loongson LS7A PCIE port has a hardware bug about PCI class. As far as
> > I know, the latest version has already fixed this bug.
> >
> > In order to maintain downward compatibility, use DECLARE_PCI_FIXUP_EARLY
> > instead of DECLARE_PCI_FIXUP_HEADER for bridge_class_quirk() to fix it as
> > early as possible.
> >
> > Otherwise, in the function pci_setup_device(), the related code about
> > "dev->class" such as "class = dev->class >> 8;" and "dev->transparent
> > = ((dev->class & 0xff) == 1);" maybe get wrong value due to without
> > EARLY fixup.
> >
> > By the way, we can see that the PCI class fixup of other controllers are
> > all EARLY fixups:
> >
> > [root@linux linux.git]# grep -rn -A 3 "PCI_CLASS_BRIDGE_PCI << 8" drivers/pci/controller/ | grep EARLY
> > drivers/pci/controller/pcie-tango.c-327-DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_SIGMA, 0x0024, tango_fixup_class);
> > drivers/pci/controller/pcie-tango.c-328-DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_SIGMA, 0x0028, tango_fixup_class);
> > drivers/pci/controller/pci-tegra.c-775-DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_NVIDIA, 0x0bf0, tegra_pcie_fixup_class);
> > drivers/pci/controller/pci-tegra.c-776-DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_NVIDIA, 0x0bf1, tegra_pcie_fixup_class);
> > drivers/pci/controller/dwc/pcie-qcom.c-1442-DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_QCOM, 0x0101, qcom_fixup_class);
> > drivers/pci/controller/dwc/pcie-qcom.c-1443-DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_QCOM, 0x0104, qcom_fixup_class);
> > drivers/pci/controller/pcie-iproc-bcma.c-23-DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_BROADCOM, 0x8011, bcma_pcie2_fixup_class);
> > drivers/pci/controller/pcie-iproc-bcma.c-24-DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_BROADCOM, 0x8012, bcma_pcie2_fixup_class);
> >
> > Fixes: 1f58cca5cf2b ("PCI: Add Loongson PCI Controller support")
> > Signed-off-by: Tiezhu Yang <yangtiezhu@xxxxxxxxxxx>
> > ---
> >
> > v2: Modify the patch subject used with lower case "loongson"
> >
> > v3: Update the commit message
> >
> >   drivers/pci/controller/pci-loongson.c | 6 +++---
> >   1 file changed, 3 insertions(+), 3 deletions(-)
> >
> > diff --git a/drivers/pci/controller/pci-loongson.c b/drivers/pci/controller/pci-loongson.c
> > index 459009c..58b862a 100644
> > --- a/drivers/pci/controller/pci-loongson.c
> > +++ b/drivers/pci/controller/pci-loongson.c
> > @@ -37,11 +37,11 @@ static void bridge_class_quirk(struct pci_dev *dev)
> >   {
> >          dev->class = PCI_CLASS_BRIDGE_PCI << 8;
> >   }
> > -DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_LOONGSON,
> > +DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_LOONGSON,
> >                          DEV_PCIE_PORT_0, bridge_class_quirk);
> > -DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_LOONGSON,
> > +DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_LOONGSON,
> >                          DEV_PCIE_PORT_1, bridge_class_quirk);
> > -DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_LOONGSON,
> > +DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_LOONGSON,
> >                          DEV_PCIE_PORT_2, bridge_class_quirk);
> >
> >   static void system_bus_quirk(struct pci_dev *pdev)
> > --
> > 2.1.0