[Query] Direction of adding arm64 support to PCIe designware driver

[Lorenzo Pieralisi]

Hi Jisheng,

On Fri, Apr 03, 2015 at 10:46:21AM +0100, Jisheng Zhang wrote:
> Hi all,
> 
> Currently, the pci designware driver still lacks of arm64 support and I noticed
> that many works are done to achieve this goal.
> 
> Some patches are merged and some are under discussion. And Per my understanding, 
> even w/ these patches merged, the driver still doesn't support arm64. Could you
> please kindly point out the direction to add arm64 support to the PCIe
> designware driver?

We should remove pci_sys_data dependency since ARM depends on that.
I removed it from a couple of places already (eg pci_mmap_page_range).

Now, pcibios_align_resource and pcibios_msi_controller need patching.

I have a patch for pcibios_align_resource() (I am waiting for Yijing
Wang series to get merged so that we can move the align_resource
function pointer in the host bridge):

https://lkml.org/lkml/2015/4/3/171

For MSI, code converted to use CONFIG_PCI_MSI_IRQ_DOMAIN should
not need pcibios_msi_controller ARM function, but if we still compile
that function in we do need pci_sys_data on ARM, so we have to have
it even if it can be dead code in some platforms, I have to vet all
ARM PCI host controllers to check, but removing it would break MSI
support.

Does it help ? MSIs are the most important change required,
align_resource() pointer can be sorted out easily once Yijing's
code gets in.

Lorenzo