On Wed, May 21, 2014 at 04:45:29PM +0530, Sunil Kovvuri wrote:
Hi Liviu,
Sorry for the trouble. I got why 'res->parent' is not set in my case. Basically my SR-IOV device has fixed resources, so resources will not be allocated/assigned and hence parent resource is not set. I will move the resource claiming to host controller driver as a fixup so that parent resource hierarchy is set.
Thanks for the support.
Glad you worked out the cause for the problem. I will still at to my list of ToDo things to investigate resource parenting with my patchset.
Best regards, Liviu
Regards, Sunil.
On Fri, May 16, 2014 at 11:12 PM, Sunil Kovvuri sunil.kovvuri@gmail.com wrote:
Hi Liviu,
Issue may not be only with SR-IOV resources.
I am not an expert with Linux PCI core. But i am trying to understand how even for a non SR-IOV capable device's resource, gets a parent associated with it.
When a PCI device driver calls pci_enable_device() which inturn calls 'arch/arm64/kernel/pci.c' pcibios_enable_device() which uses Linux PCI core API 'pci_enable_resources'. This API checks 'res->parent' for all valid resources before enabling them, otherwise it fails. if (!r->parent) { dev_err(&dev->dev, "device not available " "(can't reserve %pR)\n", r); return -EINVAL; }
Can you please let me know where this hierarchy is being set for 'pcibios_enable_resources' to work.
I could only find request_resource() API which sets the parent and pci_claim_resource() uses this.
Thanks, Sunil.
On Fri, May 16, 2014 at 6:54 PM, Liviu Dudau Liviu.Dudau@arm.com wrote:
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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