On Sun, Nov 02, 2014 at 11:41:24PM +0800, Wei Yang wrote:
> From: Gavin Shan <gws...@linux.vnet.ibm.com>
>
> pci_dn is the extension of PCI device node and it's created from
> device node. Unfortunately, VFs that are enabled dynamically by
> PF's driver and they don't have corresponding device nodes, and
> pci_dn. The patch refactors pci_dn to support VFs:
>
> * pci_dn is organized as a hierarchy tree. VF's pci_dn is put
> to the child list of pci_dn of PF's bridge. pci_dn of other
> device put to the child list of pci_dn of its upstream bridge.
>
> * VF's pci_dn is expected to be created dynamically when applying
> final fixup to PF. VF's pci_dn will be destroyed when releasing
> PF's pci_dev instance. pci_dn of other device is still created
> from device node as before.
>
> * For one particular PCI device (VF or not), its pci_dn can be
> found from pdev->dev.archdata.firmware_data, PCI_DN(devnode),
> or parent's list. The fast path (fetching pci_dn through PCI
> device instance) is populated during early fixup time.
>
> Signed-off-by: Gavin Shan <gws...@linux.vnet.ibm.com>
> ---
> ...
> +struct pci_dn *add_dev_pci_info(struct pci_dev *pdev)
> +{
> +#ifdef CONFIG_PCI_IOV
> + struct pci_dn *parent, *pdn;
> + int i;
> +
> + /* Only support IOV for now */
> + if (!pdev->is_physfn)
> + return pci_get_pdn(pdev);
> +
> + /* Check if VFs have been populated */
> + pdn = pci_get_pdn(pdev);
> + if (!pdn || (pdn->flags & PCI_DN_FLAG_IOV_VF))
> + return NULL;
> +
> + pdn->flags |= PCI_DN_FLAG_IOV_VF;
> + parent = pci_bus_to_pdn(pdev->bus);
> + if (!parent)
> + return NULL;
> +
> + for (i = 0; i < pci_sriov_get_totalvfs(pdev); i++) {
> + pdn = add_one_dev_pci_info(parent, NULL,
> + pci_iov_virtfn_bus(pdev, i),
> + pci_iov_virtfn_devfn(pdev, i));
I'm not sure this makes sense, but I certainly don't know this code, so
maybe I'm missing something.
pci_iov_virtfn_bus() and pci_iov_virtfn_devfn() depend on
pdev->sriov->stride and pdev->sriov->offset. These are read from VF Stride
and First VF Offset in the SR-IOV capability by sriov_init(), which is
called before add_dev_pci_info():
pci_scan_child_bus
pci_scan_slot
pci_scan_single_device
pci_device_add
pci_init_capabilities
pci_iov_init(PF)
sriov_init(PF, pos)
pci_write_config_word(dev, pos + PCI_SRIOV_NUM_VF, 0)
pci_read_config_word(dev, pos + PCI_SRIOV_VF_OFFSET, &offset)
pci_read_config_word(dev, pos + PCI_SRIOV_VF_STRIDE, &stride)
iov->offset = offset
iov->stride = stride
pci_bus_add_devices
pci_bus_add_device
pci_fixup_device(pci_fixup_final)
add_dev_pci_info
pci_iov_virtfn_bus
return ... + sriov->offset + (sriov->stride * id) ...
But both First VF Offset and VF Stride change when ARI Capable Hierarchy or
NumVFs changes (SR-IOV spec sec 3.3.9, 3.3.10). We set NumVFs to zero in
sriov_init() above. We will change NumVFs to something different when a
driver calls pci_enable_sriov():
pci_enable_sriov
sriov_enable
pci_write_config_word(dev, iov->pos + PCI_SRIOV_NUM_VF, nr_virtfn)
Now First VF Offset and VF Stride have changed from what they were when we
called pci_iov_virtfn_bus() above.
> + if (!pdn) {
> + pr_warn("%s: Cannot create firmware data "
> + "for VF#%d of %s\n",
> + __func__, i, pci_name(pdev));
> + return NULL;
> + }
> + }
> +#endif
> +
> + return pci_get_pdn(pdev);
> +}
> ...
> +static void pci_dev_pdn_create(struct pci_dev *pdev)
> +{
> + add_dev_pci_info(pdev);
> +}
> +DECLARE_PCI_FIXUP_FINAL(PCI_ANY_ID, PCI_ANY_ID, pci_dev_pdn_create);
There are no other callers of add_dev_pci_info(), so it seems pointless to
declare it in arch/powerpc/include/asm/pci-bridge.h and add this wrapper
around it.
> +
> +static void pci_dev_pdn_setup(struct pci_dev *pdev)
> +{
> + struct pci_dn *pdn;
> +
> + if (pdev->dev.archdata.firmware_data)
> + return;
> +
> + /* Setup the fast path */
> + pdn = pci_get_pdn(pdev);
> + pdev->dev.archdata.firmware_data = pdn;
> +}
> +DECLARE_PCI_FIXUP_EARLY(PCI_ANY_ID, PCI_ANY_ID, pci_dev_pdn_setup);
> --
> 1.7.9.5
>
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