[v6,4/7] PCI: Add fwnode_handle to pci_sysdata

From: Jake Oshins <jakeo@microsoft.com>

This patch adds an fwnode_handle to struct pci_sysdata, which is
used by the next patch in the series when trying to locate an
IRQ domain associated with a root PCI bus.

Signed-off-by: Jake Oshins <jakeo@microsoft.com>
---
 arch/x86/include/asm/pci.h | 13 +++++++++++++
 include/asm-generic/pci.h  |  4 ++++
 2 files changed, 17 insertions(+)

On 2015/11/3 5:33, jakeo@microsoft.com wrote:
> From: Jake Oshins <jakeo@microsoft.com>
> 
> This patch adds an fwnode_handle to struct pci_sysdata, which is
> used by the next patch in the series when trying to locate an
> IRQ domain associated with a root PCI bus.
> 
> Signed-off-by: Jake Oshins <jakeo@microsoft.com>
> ---
>  arch/x86/include/asm/pci.h | 13 +++++++++++++
>  include/asm-generic/pci.h  |  4 ++++
>  2 files changed, 17 insertions(+)
> 
> diff --git a/arch/x86/include/asm/pci.h b/arch/x86/include/asm/pci.h
> index 4625943..fb74453 100644
> --- a/arch/x86/include/asm/pci.h
> +++ b/arch/x86/include/asm/pci.h
> @@ -20,6 +20,9 @@ struct pci_sysdata {
>  #ifdef CONFIG_X86_64
>  	void		*iommu;		/* IOMMU private data */
>  #endif
> +#ifdef CONFIG_PCI_MSI_IRQ_DOMAIN
> +	void		*fwnode;	/* IRQ domain for MSI assignment */
> +#endif
>  };
>  
>  extern int pci_routeirq;
> @@ -41,6 +44,16 @@ static inline int pci_proc_domain(struct pci_bus *bus)
>  }
>  #endif
>  
> +#ifdef CONFIG_PCI_MSI_IRQ_DOMAIN
> +static inline void *_pci_root_bus_fwnode(struct pci_bus *bus)
> +{
> +	struct pci_sysdata *sd = bus->sysdata;
> +	return sd->fwnode;
> +}
> +
> +#define pci_root_bus_fwnode	_pci_root_bus_fwnode
> +#endif
> +
>  /* Can be used to override the logic in pci_scan_bus for skipping
>     already-configured bus numbers - to be used for buggy BIOSes
>     or architectures with incomplete PCI setup by the loader */
> diff --git a/include/asm-generic/pci.h b/include/asm-generic/pci.h
> index f24bc51..3fde985 100644
> --- a/include/asm-generic/pci.h
> +++ b/include/asm-generic/pci.h
> @@ -21,4 +21,8 @@ static inline int pci_get_legacy_ide_irq(struct pci_dev *dev, int channel)
>  #define PCI_DMA_BUS_IS_PHYS	(1)
>  #endif
>  
> +#ifndef pci_root_bus_fwnode
> +#define pci_root_bus_fwnode(bus)	((void)(bus),NULL)
> +#endif
Hi Jakeo,
	For x86, all PCI devices share the same MSI controller. But I'm
not sure whether it may have per-bus/per-device MSI controllers on other
archs. If there may be multiple MSI controllers serving PCI devices
under the same PCI root, it would be better to use some thing like
pci_get_msi_fwnode(bus) or similar.
Thanks,
Gerry


> +
>  #endif /* _ASM_GENERIC_PCI_H */
> 
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> -----Original Message-----
> From: Jiang Liu [mailto:jiang.liu@linux.intel.com]
> Sent: Wednesday, December 2, 2015 10:53 PM
> To: Jake Oshins <jakeo@microsoft.com>; gregkh@linuxfoundation.org; KY
> Srinivasan <kys@microsoft.com>; linux-kernel@vger.kernel.org;
> devel@linuxdriverproject.org; olaf@aepfle.de; apw@canonical.com;
> vkuznets@redhat.com; tglx@redhat.com; Haiyang Zhang
> <haiyangz@microsoft.com>; marc.zyngier@arm.com;
> bhelgaas@google.com; linux-pci@vger.kernel.org
> Subject: Re: [PATCH v6 4/7] PCI: Add fwnode_handle to pci_sysdata
> 
> On 2015/11/3 5:33, jakeo@microsoft.com wrote:
> > From: Jake Oshins <jakeo@microsoft.com>

> >
> > +#ifdef CONFIG_PCI_MSI_IRQ_DOMAIN
> > +static inline void *_pci_root_bus_fwnode(struct pci_bus *bus)
> > +{
> > +	struct pci_sysdata *sd = bus->sysdata;
> > +	return sd->fwnode;
> > +}
> > +
> > +#define pci_root_bus_fwnode	_pci_root_bus_fwnode
> > +#endif
> > +
> >  /* Can be used to override the logic in pci_scan_bus for skipping
> >     already-configured bus numbers - to be used for buggy BIOSes
> >     or architectures with incomplete PCI setup by the loader */
> > diff --git a/include/asm-generic/pci.h b/include/asm-generic/pci.h
> > index f24bc51..3fde985 100644
> > --- a/include/asm-generic/pci.h
> > +++ b/include/asm-generic/pci.h
> > @@ -21,4 +21,8 @@ static inline int pci_get_legacy_ide_irq(struct pci_dev
> *dev, int channel)
> >  #define PCI_DMA_BUS_IS_PHYS	(1)
> >  #endif
> >
> > +#ifndef pci_root_bus_fwnode
> > +#define pci_root_bus_fwnode(bus)	((void)(bus),NULL)
> > +#endif
> Hi Jakeo,
> 	For x86, all PCI devices share the same MSI controller. But I'm
> not sure whether it may have per-bus/per-device MSI controllers on other
> archs. If there may be multiple MSI controllers serving PCI devices
> under the same PCI root, it would be better to use some thing like
> pci_get_msi_fwnode(bus) or similar.
> Thanks,
> Gerry
> 

Certainly other architectures have per-bus MSI controllers, though usually it's per root complex.  In case you're not familiar with PCI Express terms (and I apologize for this if you are) a root complex is one instance of PCI Express, where traffic is defined between every part of it.  If your traffic leaves PCI Express and goes onto some processor-specific bus, it has left the root complex.  The root complex is usually modeled as a root PCI bus, a set of root port, and a set of legacy and/or embedded endpoints, which amounts to saying that some PCI/E devices are built into the root complex and not connected with links.

I don't have a use case at the moment for anything other than an MSI controller for a root complex.  If you'd like me to change this so that it more naturally extends to a situation where you'd want to use it for a specific bus, I can do that.  Please let me know.

And thanks again for your review.

-- Jake Oshins
 

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