Re: [Resend with Ack][PATCH v1] PCI: allow acpiphp to handle PCIe ports without native PCIe hotplug capability

[Jiang Liu <jiang.liu@huawei.com>]

Sure, let's try it.

On 2012-7-3 23:59, Bjorn Helgaas wrote:
> Thinking about this some more, this still leaves the callers
> responsible for using pcie_cap_has_*(), which feels pretty
> error-prone.
> 
> I wonder if it'd be worth adding interfaces like:
> 
>   pcie_cap_read_word(const struct pci_dev *, int where, u16 *val);
>   pcie_cap_read_dword(const struct pci_dev *, int where, u32 *val);
>   pcie_cap_write_word(const struct pci_dev *, int where, u16 val);
>   pcie_cap_write_dword(const struct pci_dev *, int where, u32 val);
> 
> We might be able to encapsulate the v1/v2 differences inside these, e.g.,
> 
>   int pcie_cap_read_word(const struct pci_dev *dev, int where, u16 *val)
>   {
>       int pos;
> 
>       pos = pci_pcie_cap(dev);
>       if (!pos)
>           return -EINVAL;
> 
>       switch (where) {
>       case PCI_EXP_FLAGS:
>       case PCI_EXP_DEVCTL:
>       case PCI_EXP_DEVSTA:
>           return pci_read_config_word(dev, pos + where, val);
>       case PCI_EXP_LNKCTL:
>       case PCI_EXP_LNKSTA:
>           if (pcie_cap_has_lnkctl(dev))
>               return pci_read_config_word(dev, pos + where, val);
>           else {
>               *val = 0;
>               return 0;
>           }
>       case PCI_EXP_SLTCTL:
>       case PCI_EXP_SLTSTA:
>           if (pcie_cap_has_sltctl(dev))
>               return pci_read_config_word(dev, pos + where, val);
>           else {
>               *val = 0;
>               if (where == PCI_EXP_SLTSTA && dev->pcie_type ==
> PCI_EXP_TYPE_DOWNSTREAM)
>                   *val = PCI_EXP_SLTSTA_PDS;
>               return 0;
>       ...
>       };
>       return -EINVAL;
>   }
> 
> Any thoughts?
> 
> .
>