[PATCH v5 1/5] ARM/PCI: remove align_resource in pci_sys_data

Rob Herring robh at kernel.org
Thu Jul 30 15:48:14 PDT 2015

On Tue, Jul 28, 2015 at 12:44 PM, Lorenzo Pieralisi
<lorenzo.pieralisi at arm.com> wrote:
> [CC'ing RMK]
> On Tue, Jul 28, 2015 at 08:17:18AM +0100, Zhou Wang wrote:
>> On 2015/7/25 11:21, Zhou Wang wrote:
>> > From: Gabriele Paoloni <gabriele.paoloni at huawei.com>
>> >
>> > This patch is needed in order to unify the PCIe designware framework for ARM and
>> > ARM64 architectures. In the PCIe designware unification process we are calling
>> > pci_create_root_bus() passing a "sysdata" parameter that is the same for both
>> > ARM and ARM64 and is of type "struct pcie_port*". In the ARM case this will
>> > cause a problem with the function pcibios_align_resource(); in fact this will
>> > cast "dev->sysdata" to "struct pci_sys_data*", whereas designware had passed a
>> > "struct pcie_port*" pointer.
>> >
>> > This patch solves the issue by removing "align_resource" from "pci_sys_data"
>> > struct and defining a static global function pointer in "bios32.c"
>> >
>> > Signed-off-by: Gabriele Paoloni <gabriele.paoloni at huawei.com>
>> Hi Arnd and Rob,
>> What is your opinion about this patch? Gabriele adds a global pointer in bios32.c
>> to store align_resource, so we could remove sys->align_resource in pcibios_align_resource.
>> As Lorenzo mentioned in v4 series, this is a temporary solution before moving
>> align_resource to host bridge structure.
>> Any comments welcome.
> The align_resource() pointer is just used in drivers/pci/host/pci-mvebu.c,
> I would like the pci-mvebu.c maintainers to comment on this and test it, I
> do not expect it to create any issue and might be a temporary solution to
> make progress on ARM/ARM64 consolidation, it is a blocking point.
> It would be good if Russell can have a look too, I do not see what
> issue this can trigger given that is just used in:

It's Russell's call on this if you want to touch bios32.c...

> drivers/pci/host/pci-mvebu.c
> and a global pointer (not saying it is elegant, but it should work)
> might be ok.
> So yes, comments very welcome.

I may be wrong, but I don't think even mvebu needs this as part of
pcibios_align_resource. pcibios_align_resource is called for every
device, but all mvebu should care about is the alignment of the root
bus BARs (and corresponding MBus windows) which can be handled in
probe. I can't see how regions within there matter. But that is just
my 10 minute look at it.

If not, then I think align_resource should be a common per host
function ptr. In other words, think about how to provide a default
implementation of pcibios_align_resource. They almost all look the
same to me with the same I/O 0x3xx address handling.


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