[PATCH v3 11/12] ARM: mvebu: Relocate Armada 370 PCIe device tree nodes
Ezequiel Garcia
ezequiel.garcia at free-electrons.com
Wed Jun 19 21:12:58 EST 2013
Arnd,
Going through this a couple questions came out...
On Tue, Jun 18, 2013 at 11:35:50PM +0200, Arnd Bergmann wrote:
> On Tuesday 18 June 2013, Ezequiel Garcia wrote:
> > +
> > + ranges =
> > + <0x82000000 0 0x40000 0xffff0001 0x40000 0 0x00002000
> > + 0x82000000 0 0x80000 0xffff0001 0x80000 0 0x00002000
> > + 0x82000000 0 0xe0000000 0xffff0002 0 0 0x08000000
> > + 0x81000000 0 0 0xffff0002 0x8000000 0 0x00100000>;
>
> As pointed out on IRC, this is not a good representation of the memory space,
> since it requires a non-zero sys->mem_offset, and it conflicts with the straight
> mapping I suggested.
>
> I think it should be
>
> 0x82000000 0 0xe0000000 0xffff0002 0 0xe0000000 0x08000000
So far, so good.
>
> if we want to encode the aperture in the ranges property here, i.e. have
> a 1:1 mapping between PCI memory space and MBUS space, and in mbus,
> you need the corresponding
>
> - 0xffff0002 0 0xe0000000 0x8100000
> + 0xffff0002 0xe0000000 0xe0000000 0x8100000
... I obviously got something wrong, but I thought you said that
this change allowed to *not* have any mbus-node ranges translation.
>
> so that mbus actually translates the right addresses. You could also
> have the PCI memory space start at 0, which would mean
>
> 0x82000000 0 0 0xffff0002 0 0 0x08000000
>
> and
>
> 0xffff0002 0 0xe0000000 0x8100000
Mmm.. and why is this option acceptable?
>
> Note that the driver doesn't actually handle the generic case correctly, you would
> need to apply this patch
>
This patch does not apply. I tried to understand what you did, but I'm
confused by the fact I don't need to apply any patch to make it work
on my boxes, using your proposed ranges translations.
> diff --git a/drivers/pci/host/pci-mvebu.c b/drivers/pci/host/pci-mvebu.c
> index 13a633b..aa674f4 100644
> --- a/drivers/pci/host/pci-mvebu.c
> +++ b/drivers/pci/host/pci-mvebu.c
> @@ -790,6 +790,7 @@ static int __init mvebu_pcie_probe(struct platform_device *pdev)
> }
> if (restype == IORESOURCE_MEM) {
> of_pci_range_to_resource(&range, np, &pcie->mem);
> + sys->mem_offset = range.cpu_addr - range.pci_addr;
> pcie->mem.name = "MEM";
> }
> }
>
> to deal with the generic case where the bus address is different from the
> CPU address.
>
Thanks!
--
Ezequiel García, Free Electrons
Embedded Linux, Kernel and Android Engineering
http://free-electrons.com
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