Re: [PATCH 6/6] pci, acpi: Share ACPI PCI config space accessors.

Tomasz Nowicki
2014-11-19T16:24:30Z

On 19.11.2014 17:19, Arnd Bergmann wrote:
> On Wednesday 19 November 2014 17:04:51 Tomasz Nowicki wrote:
>> +/*
>> + * raw_pci_read/write - ACPI PCI config space accessors.
>> + *
>> + * ACPI spec defines MMCFG as the way we can access PCI config space,
>> + * so let MMCFG be default (__weak).
>> + *
>> + * If platform needs more fancy stuff, should provides its own implementation.
>> + */
>> +int __weak raw_pci_read(unsigned int domain, unsigned int bus,
>> + unsigned int devfn, int reg, int len, u32 *val)
>> +{
>> + return pci_mmcfg_read(domain, bus, devfn, reg, len, val);
>> +}
>> +
>> +int __weak raw_pci_write(unsigned int domain, unsigned int bus,
>> + unsigned int devfn, int reg, int len, u32 val)
>> +{
>> + return pci_mmcfg_write(domain, bus, devfn, reg, len, val);
>> +}
>> +
>>
>
> I think it would be better to avoid __weak functions here, as they tend
> to be hard to follow when trying to understand the code.
>
> How about using a Kconfig symbol like this:
>
> #ifdef CONFIG_ARCH_RAW_PCI_READWRITE
> int raw_pci_read(unsigned int domain, unsigned int bus, unsigned int devfn,
> int reg, int len, u32 *val);
> int raw_pci_write(unsigned int domain, unsigned int bus, unsigned int devfn,
> int reg, int len, u32 val);
> #else
> static inline int raw_pci_read(unsigned int domain, unsigned int bus,
> unsigned int devfn, int reg, int len, u32 *val)
> {
> return pci_mmcfg_read(domain, bus, devfn, reg, len, val);
> }
>
> static inline int raw_pci_write(unsigned int domain, unsigned int bus,
> unsigned int devfn, int reg, int len, u32 val)
> {
> return pci_mmcfg_write(domain, bus, devfn, reg, len, val);
> }
> #endif
>
> Same thing for the weak symbols in patch 5.
>

It makes sense to me, thanks!

Tomasz