Re: [PATCH v7 0/3] Add support for PCI in AArch64

Liviu Dudau
2014-05-16T13:24:58Z

Hi Sunil,

On Fri, May 16, 2014 at 11:33:04AM +0100, Sunil Kovvuri wrote:
> Hi Liviu,
>
> I am using your ARM64 PCIe patches to write a PCIe host controller
> driver for our SOC. I am facing an issue with SR-IOV capable device.
>
> Consider an PCI Express endpoint connected to a PCI Express
> Root Port. The PCI Express endpoint provides PCI-SIG SR-IOV
> capabilities with a single physical function and a large number
> of virtual functions. The Root Port contains a pci-pci bridge in
> between it and the SR-IOV device.
>
> When the SR-IOV capable device's driver tries to enable sriov
> (pci_enable_sriov()) it fails to create/add PCI device for each
> virtual function reporting "not enough MMIO resources for SR-IOV".
>
> In sriov_enable() (drivers/pci/iov.c)
>
> 296 for (i = 0; i < PCI_SRIOV_NUM_BARS; i++) {
> 297 bars |= (1 << (i + PCI_IOV_RESOURCES));
> 298 res = dev->resource + PCI_IOV_RESOURCES + i;
> 299 if (res->parent)
> 300 nres++;
> 301 }
> 302 if (nres != iov->nres) {
> 303 dev_err(&dev->dev, "not enough MMIO resources for
> SR-IOV\n");
> 304 return -ENOMEM;
> 305 }
>
> Here its checking if physical function's IOV resource has a parent or not.
> Which is pci-pci bridge in this case. Otherwise it doesn't consider
> that resource.
>
> Added below api to your patch.
> This will try to claim a resource while creating a PCI device which
> inturn sets 'res->parent'.
>
> Let me know if this is okay.
>
> diff --git a/arch/arm64/kernel/pci.c b/arch/arm64/kernel/pci.c
> index 9f29c9a..fbfb48f 100644
> --- a/arch/arm64/kernel/pci.c
> +++ b/arch/arm64/kernel/pci.c
> @@ -125,6 +125,21 @@ resource_size_t pcibios_align_resource(void
> *data, const struct resource *res,
> return res->start;
> }
>
> +int pcibios_add_device(struct pci_dev *pdev)
> +{
> + unsigned int i, type_mask = IORESOURCE_IO | IORESOURCE_MEM;
> + struct resource *res;
> +
> + for (i = 0; i < PCI_NUM_RESOURCES; i++) {
> + res = &pdev->resource[i];
> + if (res->parent || !(res->flags & type_mask))
> + continue;
> + pci_claim_resource(pdev, i);
> + }
> +
>

I would like not to have to add your patch in this file as I am trying to
remove it entirely. I don't have an SR-IOV capable device in my setup so
I am not able to debug your problem, but could you have a go and try to
figure out why the SR-IOV resources do not get a parent associated with
when they get created?

Many thanks,
Liviu

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