Re: [PATCH v1 1/2] PCI: Stub out read/write/raw/find functions

[Bjorn Helgaas <helgaas@kernel.org>]

On Sat, Dec 01, 2018 at 08:41:35PM +0000, Sinan Kaya wrote:
> Need stub functions in order to be able to compile ACPI without PCI
> support.
> 
> Signed-off-by: Sinan Kaya <okaya@kernel.org>

I can't tell where this series is since I only got the pieces that
touch PCI and the version numbers and n/n numbers don't make much
sense then, so apologies if I'm responding to an obsolete patch.

> ---
>  include/linux/pci.h | 32 ++++++++++++++++++++++++++++++++
>  1 file changed, 32 insertions(+)
> 
> diff --git a/include/linux/pci.h b/include/linux/pci.h
> index 11c71c4ecf75..15407f469d41 100644
> --- a/include/linux/pci.h
> +++ b/include/linux/pci.h
> @@ -682,10 +682,22 @@ struct pci_ops {
>   * ACPI needs to be able to access PCI config space before we've done a
>   * PCI bus scan and created pci_bus structures.
>   */
> +#ifdef CONFIG_PCI
>  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)
> +{
> +	*val = 0;
> +	return -EINVAL;

Why do you return 0 here?  If a PCI config access fails, you usually
get ~0.

> +}
> +static inline int raw_pci_write(unsigned int domain, unsigned int bus,
> +				unsigned int devfn, int reg, int len, u32 val)
> +{ return -EINVAL; }
> +#endif
>  
>  #ifdef CONFIG_ARCH_DMA_ADDR_T_64BIT
>  typedef u64 pci_bus_addr_t;
> @@ -1599,7 +1611,27 @@ pci_release_mem_regions(struct pci_dev *pdev)
>  }
>  
>  #else /* CONFIG_PCI is not enabled */
> +static inline int pci_bus_read_config_byte(struct pci_bus *bus,
> +		unsigned int devfn, int where, u8 *val)
> +{ return -EINVAL; }

Should these set *val as well?  To ~0 (or 0) to match above, I assume?

> +static inline int pci_bus_read_config_word(struct pci_bus *bus,
> +		unsigned int devfn, int where, u16 *val)
> +{ return -EINVAL; }
> +static inline int pci_bus_read_config_dword(struct pci_bus *bus,
> +		unsigned int devfn, int where, u32 *val)
> +{ return -EINVAL; }
> +static inline int pci_bus_write_config_byte(struct pci_bus *bus,
> +		unsigned int devfn, int where, u8 val)
> +{ return -EINVAL; }
> +static inline int pci_bus_write_config_word(struct pci_bus *bus,
> +		unsigned int devfn, int where, u16 val)
> +{ return -EINVAL; }
> +static inline int pci_bus_write_config_dword(struct pci_bus *bus,
> +		unsigned int devfn, int where, u32 val)
> +{ return -EINVAL; }
> +static inline struct pci_bus *pci_find_bus(int domain, int busnr)
> +{ return NULL; }
>  static inline void pci_set_flags(int flags) { }
>  static inline void pci_add_flags(int flags) { }
>  static inline void pci_clear_flags(int flags) { }
> -- 
> 2.19.0
>