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

On Tue, Jul 28, 2015 at 12:44 PM, Lorenzo Pieralisi
[off-list ref] wrote:

[CC'ing RMK]

On Tue, Jul 28, 2015 at 08:17:18AM +0100, Zhou Wang wrote:

quoted

On 2015/7/25 11:21, Zhou Wang wrote:

quoted

From: Gabriele Paoloni <redacted>

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 <redacted>

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.

Rob