[PATCH v5 06/19] PCI/MSI: of: Allow msi_domain lookup using the host bridge node

[Bjorn Helgaas]

On Thu, Jul 23, 2015 at 10:26:25AM +0100, Marc Zyngier wrote:
> A number of platforms do not need to use the msi-parent property,
> as the host bridge itself provides the MSI controller.
> 
> Allow this configuration by performing an irq domain lookup based
> on the host bridge node if it doesn't have a valid msi-parent property.
> 
> Signed-off-by: Marc Zyngier <marc.zyngier at arm.com>

Acked-by: Bjorn Helgaas <bhelgaas at google.com>

> ---
>  drivers/pci/of.c | 11 ++++++++++-
>  1 file changed, 10 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/pci/of.c b/drivers/pci/of.c
> index e2ebb7d..fcfdadf 100644
> --- a/drivers/pci/of.c
> +++ b/drivers/pci/of.c
> @@ -69,12 +69,21 @@ struct irq_domain *pci_host_bridge_of_msi_domain(struct pci_bus *bus)
>  
>  	if (!bus->dev.of_node)
>  		return NULL;
> +
> +	/* Start looking for a phandle to an MSI controller. */
>  	np = of_parse_phandle(bus->dev.of_node, "msi-parent", 0);
> +
> +	/*
> +	 * If we don't have an msi-parent property, look for a domain
> +	 * directly attached to the host bridge.
> +	 */
>  	if (!np)
> -		return NULL;
> +		np = bus->dev.of_node;
> +
>  	d = irq_find_matching_host(np, DOMAIN_BUS_PCI_MSI);
>  	if (!d)
>  		d = irq_find_host(np);
> +
>  	return d;
>  #else
>  	return NULL;
> -- 
> 2.1.4
>