Thread (70 messages) 70 messages, 6 authors, 2014-09-29

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

From: Yijing Wang <hidden>
Date: 2014-09-26 02:10:47
Also in: linux-arch, linux-arm-kernel, linux-iommu, linux-mips, linux-pci, linux-s390, lkml, sparclinux

On 2014/9/25 15:26, Thierry Reding wrote:
On Thu, Sep 25, 2014 at 11:14:16AM +0800, Yijing Wang wrote:
quoted
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
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