Re: [PATCH 2/6] PCI/MSI: add hooks to populate the msi_domain field

[Bjorn Helgaas <bhelgaas@google.com>]

On Mon, Dec 08, 2014 at 08:12:19PM +0000, Marc Zyngier wrote:
> In order to be able to populate the device msi_domain field,
> add the necesary hooks to propagate the PHB msi_domain across
> secondary busses to devices.
> 
> So far, nobody populates the initial msi_domain.
> 
> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
> ---
>  drivers/pci/probe.c | 24 ++++++++++++++++++++++++
>  include/linux/pci.h |  1 +
>  2 files changed, 25 insertions(+)
> 
> diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
> index c8ca98c..d1009a2 100644
> --- a/drivers/pci/probe.c
> +++ b/drivers/pci/probe.c
> @@ -670,6 +670,20 @@ static void pci_set_bus_speed(struct pci_bus *bus)
>  	}
>  }
>  
> +void __weak pcibios_set_phb_msi_domain(struct pci_bus *bus)

We haven't previously used the "phb" abbreviation in the PCI core, so I'd
rather not start now.  I'm not really sure how relevant it is anyway --
maybe the name doesn't need to include a reference to the host bridge at
all?

> +{
> +}
> +
> +static void pci_set_bus_msi_domain(struct pci_bus *bus)
> +{
> +	struct pci_dev *bridge = bus->self;
> +
> +	if (!bridge)
> +		pcibios_set_phb_msi_domain(bus);
> +	else
> +		dev_set_msi_domain(&bus->dev, dev_get_msi_domain(&bridge->dev));
> +}
> +
>  static struct pci_bus *pci_alloc_child_bus(struct pci_bus *parent,
>  					   struct pci_dev *bridge, int busnr)
>  {
> @@ -723,6 +737,7 @@ static struct pci_bus *pci_alloc_child_bus(struct pci_bus *parent,
>  	bridge->subordinate = child;
>  
>  add_dev:
> +	pci_set_bus_msi_domain(child);
>  	ret = device_register(&child->dev);
>  	WARN_ON(ret < 0);
>  
> @@ -1517,6 +1532,11 @@ static void pci_init_capabilities(struct pci_dev *dev)
>  	pci_enable_acs(dev);
>  }
>  
> +static void pci_set_msi_domain(struct pci_dev *dev)
> +{
> +	dev_set_msi_domain(&dev->dev, dev_get_msi_domain(&dev->bus->dev));
> +}
> +
>  void pci_device_add(struct pci_dev *dev, struct pci_bus *bus)
>  {
>  	int ret;
> @@ -1546,6 +1566,9 @@ void pci_device_add(struct pci_dev *dev, struct pci_bus *bus)
>  	/* Initialize various capabilities */
>  	pci_init_capabilities(dev);
>  
> +	/* Setup MSI irq domain */

This is *really* a nitpick, but "setup" suggests that we're doing more than
just setting a pointer, i.e., it suggests that we're doing something more
involved to get it all ready for use.  But here, I think we really are just
setting a pointer, so I think the comment is pointless since the function
name already says that.

> +	pci_set_msi_domain(dev);
> +
>  	/*
>  	 * Add the device to our list of discovered devices
>  	 * and the bus list for fixup functions, etc.
> @@ -1947,6 +1970,7 @@ struct pci_bus *pci_create_root_bus(struct device *parent, int bus,
>  	b->bridge = get_device(&bridge->dev);
>  	device_enable_async_suspend(b->bridge);
>  	pci_set_bus_of_node(b);
> +	pci_set_bus_msi_domain(b);
>  
>  	if (!parent)
>  		set_dev_node(b->bridge, pcibus_to_node(b));
> diff --git a/include/linux/pci.h b/include/linux/pci.h
> index a523cee..3266764 100644
> --- a/include/linux/pci.h
> +++ b/include/linux/pci.h
> @@ -1637,6 +1637,7 @@ int pcibios_set_pcie_reset_state(struct pci_dev *dev,
>  int pcibios_add_device(struct pci_dev *dev);
>  void pcibios_release_device(struct pci_dev *dev);
>  void pcibios_penalize_isa_irq(int irq, int active);
> +void pcibios_set_phb_msi_domain(struct pci_bus *bus);
>  
>  #ifdef CONFIG_HIBERNATE_CALLBACKS
>  extern struct dev_pm_ops pcibios_pm_ops;
> -- 
> 2.1.3
>