Subject: [PATCH v4 12/30] PCI: Introduce pci_host_bridge_ops to support host specific operations

From: [email-masked] (Bjorn Helgaas)
Date: Mon, 2 Mar 2015 21:03:01 -0600

On Thu, Feb 26, 2015 at 04:12:06PM +0800, Yijing Wang wrote:
> Now we have weak functions like pcibios_root_bridge_prepare()
> to setup pci host bridge, We could introduce pci_host_bridge_ops
> which contain host bridge specific ops to setup pci_host_bridge.
> Then host bridge driver could add pci_host_bridge_ops hooks
> intead of weak function to setup pci_host_bridge.
> This patch add following pci_host_bridge_ops hooks:
> 
> pci_host_bridge_ops {
> 	/* set root bus speed, some platform need this like powerpc */
> 	void (*phb_set_root_bus_speed)(struct pci_host_bridge *host);
> 	/* setup pci_host_bridge before pci_host_bridge be added to driver core */
> 	int (*phb_prepare)(struct pci_host_bridge *host);
> 	/* platform specific of scan hook to scan pci device */
> 	void (*phb_of_scan_bus)(struct pci_host_bridge *);
> }
> We could easily extend it to support different host bridge
> specific operations.
> 
> Signed-off-by: Yijing Wang <[email-masked]>
> ...

> @@ -2050,10 +2052,13 @@ static struct pci_bus *__pci_scan_root_bus(
>  		pci_bus_insert_busn_res(b, b->number, 255);
>  	}
>  
> -	max = pci_scan_child_bus(b);
> -
> -	if (!found)
> -		pci_bus_update_busn_res_end(b, max);
> +	if (host->ops && host->ops->phb_of_scan_bus) {
> +		host->ops->phb_of_scan_bus(host);

The important thing here is not the use of OF (Open Firmware/Device Tree),
is it?  Why would we want "_of_" in the function name?  I assume the intent
is that this host bridge op performs the same function as
pci_scan_child_bus(), so I think the op should be called "scan_bus".

> +	} else {
> +		max = pci_scan_child_bus(b);
> +		if (!found)
> +			pci_bus_update_busn_res_end(b, max);
> +	}
>  
>  	return b;
>  }