From mboxrd@z Thu Jan  1 00:00:00 1970
From: Yijing Wang <wangyijing@huawei.com>
Date: Fri, 26 Sep 2014 02:10:23 +0000
Subject: Re: [PATCH v2 06/22] PCI/MSI: Introduce weak arch_find_msi_chip() to find MSI chip
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References: <1411614872-4009-1-git-send-email-wangyijing@huawei.com> <1411614872-4009-7-git-send-email-wangyijing@huawei.com> <20140925072619.GI12423@ulmo>
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To: Thierry Reding <thierry.reding@gmail.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>, linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org, Xinwei Hu <huxinwei@huawei.com>, Wuyun <wuyun.wu@huawei.com>, linux-arm-kernel@lists.infradead.org, Russell King <linux@arm.linux.org.uk>, linux-arch@vger.kernel.org, arnab.basu@freescale.com, Bharat.Bhushan@freescale.com, x86@kernel.org, Arnd Bergmann <arnd@arndb.de>, Thomas Gleixner <tglx@linutronix.de>, Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>, xen-devel@lists.xenproject.org, Joerg Roedel <joro@8bytes.org>, iommu@lists.linux-foundation.org, linux-mips@linux-mips.org, Benjamin Herrenschmidt <benh@kernel.crashing.org>, linuxppc-dev@lists.ozlabs.org, linux-s390@vger.kernel.org, Sebastian Ott <sebott@linux.vnet.ibm.com>, Tony Luck <tony.luck@intel.com>, linux-ia64@vger.kernel.org, "David S. Miller" <davem@davemloft.net>, sparclinux@vger.kernel.org, Chris Metcalf <cmetcalf@tilera.com>, Ralf Baechle <ralf@linux-mips.org>, Lucas Stach <l.stach@pengutronix.de>, David Vrabel <david.vrabel@citrix.com>, Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>, Michael Ellerman <mpe@ellerman.id.au>, Thomas Petazzoni <thomas.petazzoni@free-electrons.com>

On 2014/9/25 15:26, Thierry Reding wrote:
> On Thu, Sep 25, 2014 at 11:14:16AM +0800, Yijing Wang wrote:
>> Introduce weak arch_find_msi_chip() to find the match msi_chip.
>> Currently, MSI chip associates pci bus to msi_chip. Because in
>> ARM platform, there may be more than one MSI controller in system.
>> Associate pci bus to msi_chip help pci device to find the match
>> msi_chip and setup MSI/MSI-X irq correctly. But in other platform,
>> like in x86. we only need one MSI chip, because all device use
>> the same MSI address/data and irq etc. So it's no need to associate
>> pci bus to MSI chip, just use a arch function, arch_find_msi_chip()
>> to return the MSI chip for simplicity. The default weak
>> arch_find_msi_chip() used in ARM platform, find the MSI chip
>> by pci bus.
> 
> Can't x86 simply set the bus' .msi field anyway? It would seem to be
> easy to do and unifies the code rather than driving it further apart
> using even more of the __weak functions.

As mentioned in the first reply, I will rework this one when we find a better solution.

Thanks!
Yijing.

> 
> Thierry
> 


-- 
Thanks!
Yijing