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Date: Mon, 2 Mar 2015 21:03:01 -0600
From: Bjorn Helgaas <bhelgaas@google.com>
To: Yijing Wang <wangyijing@huawei.com>
Cc: Jiang Liu <jiang.liu@linux.intel.com>, linux-pci@vger.kernel.org,
        Yinghai Lu <yinghai@kernel.org>, linux-kernel@vger.kernel.org,
        Marc Zyngier <marc.zyngier@arm.com>,
        linux-arm-kernel@lists.infradead.org,
        Russell King <linux@arm.linux.org.uk>, x86@kernel.org,
        Thomas Gleixner <tglx@linutronix.de>,
        Benjamin Herrenschmidt <benh@kernel.crashing.org>,
        Rusty Russell <rusty@rustcorp.com.au>, Tony Luck <tony.luck@intel.com>,
        linux-ia64@vger.kernel.org, "David S. Miller" <davem@davemloft.net>,
        Guan Xuetao <gxt@mprc.pku.edu.cn>, linux-alpha@vger.kernel.org,
        linux-m68k@vger.kernel.org, Liviu Dudau <liviu@dudau.co.uk>,
        Arnd Bergmann <arnd@arndb.de>,
        Geert Uytterhoeven <geert@linux-m68k.org>
Subject: Re: [PATCH v4 12/30] PCI: Introduce pci_host_bridge_ops to support
 host specific operations
Message-ID: <20150303030301.GI11978@google.com>
References: <1424938344-4017-1-git-send-email-wangyijing@huawei.com>
 <1424938344-4017-13-git-send-email-wangyijing@huawei.com>
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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 <wangyijing@huawei.com>
> ...

> @@ -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;
>  }