Re: [PATCH v2 06/22] PCI/MSI: Introduce weak arch_find_msi_chip() to find MSI chip

From: Yijing Wang
Date: Thu Sep 25 2014 - 22:10:50 EST

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.


> Thierry


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