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    SubjectRe: [Resend with Ack][PATCH v1] PCI: allow acpiphp to handle PCIe ports without native PCIe hotplug capability
    Reviewed-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>
    Acked-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>

    Regards,
    Kenji Kaneshige


    (2012/06/04 16:44), Jiang Liu wrote:
    > Commit 0d52f54e2ef64c189dedc332e680b2eb4a34590a (PCI / ACPI: Make acpiphp
    > ignore root bridges using PCIe native hotplug) added code that made the
    > acpiphp driver completely ignore PCIe root complexes for which the kernel
    > had been granted control of the native PCIe hotplug feature by the BIOS
    > through _OSC. Later commit 619a5182d1f38a3d629ee48e04fa182ef9170052
    > "PCI hotplug: Always allow acpiphp to handle non-PCIe bridges" relaxed
    > the constraints to allow acpiphp driver handle non-PCIe bridges under
    > such a complex. The constraint needs to be relaxed further to allow
    > acpiphp driver to hanlde PCIe ports without native PCIe hotplug capability.
    >
    > Some MR-IOV switch chipsets, such PLX8696, support multiple virtual PCIe
    > switches and may migrate downstream ports among virtual switches.
    > To migrate a downstream port from the source virtual switch to the target,
    > the port needs to be hot-removed from the source and hot-added into the
    > target. pciehp driver can't be used here because there's no slots within
    > the virtual PCIe switch. So acpiphp driver is used to support downstream
    > port migration. A typical configuration is as below:
    > [Root w/o native PCIe HP]
    > [Upstream port of vswitch w/o native PCIe HP]
    > [Downstream port of vswitch w/ native PCIe HP]
    > [PCIe enpoint]
    >
    > Here acpiphp driver will be used to handle root ports and upstream port
    > in the virtual switch, and pciehp driver will be used to handle downstream
    > ports in the virtual switch.
    >
    > Acked-by: Rafael J. Wysocki<rjw@sisk.pl>
    > Signed-off-by: Jiang Liu<liuj97@gmail.com>
    >
    > ---
    > drivers/pci/hotplug/acpiphp_glue.c | 49 ++++++++++++++++++++++++++++-------
    > 1 files changed, 39 insertions(+), 10 deletions(-)
    >
    > diff --git a/drivers/pci/hotplug/acpiphp_glue.c b/drivers/pci/hotplug/acpiphp_glue.c
    > index 806c44f..4889448 100644
    > --- a/drivers/pci/hotplug/acpiphp_glue.c
    > +++ b/drivers/pci/hotplug/acpiphp_glue.c
    > @@ -115,6 +115,43 @@ static const struct acpi_dock_ops acpiphp_dock_ops = {
    > .handler = handle_hotplug_event_func,
    > };
    >
    > +/* Check whether device is managed by native PCIe hotplug driver */
    > +static bool device_is_managed_by_native_pciehp(struct pci_dev *pdev)
    > +{
    > + int pos;
    > + u16 reg16;
    > + u32 reg32;
    > + acpi_handle tmp;
    > + struct acpi_pci_root *root;
    > +
    > + if (!pci_is_pcie(pdev))
    > + return false;
    > +
    > + /* Check whether PCIe port supports native PCIe hotplug */
    > + pos = pci_pcie_cap(pdev);
    > + pci_read_config_word(pdev, pos + PCI_EXP_FLAGS,&reg16);
    > + if (!(reg16& PCI_EXP_FLAGS_SLOT))
    > + return false;
    > + pci_read_config_dword(pdev, pos + PCI_EXP_SLTCAP,&reg32);
    > + if (!(reg32& PCI_EXP_SLTCAP_HPC))
    > + return false;
    > +
    > + /*
    > + * Check whether native PCIe hotplug has been enabled for
    > + * this PCIe hierarchy.
    > + */
    > + tmp = acpi_find_root_bridge_handle(pdev);
    > + if (!tmp)
    > + return false;
    > + root = acpi_pci_find_root(tmp);
    > + if (!root)
    > + return false;
    > + if (!(root->osc_control_set& OSC_PCI_EXPRESS_NATIVE_HP_CONTROL))
    > + return false;
    > +
    > + return true;
    > +}
    > +
    > /* callback routine to register each ACPI PCI slot object */
    > static acpi_status
    > register_slot(acpi_handle handle, u32 lvl, void *context, void **rv)
    > @@ -133,16 +170,8 @@ register_slot(acpi_handle handle, u32 lvl, void *context, void **rv)
    > return AE_OK;
    >
    > pdev = pbus->self;
    > - if (pdev&& pci_is_pcie(pdev)) {
    > - tmp = acpi_find_root_bridge_handle(pdev);
    > - if (tmp) {
    > - struct acpi_pci_root *root = acpi_pci_find_root(tmp);
    > -
    > - if (root&& (root->osc_control_set&
    > - OSC_PCI_EXPRESS_NATIVE_HP_CONTROL))
    > - return AE_OK;
    > - }
    > - }
    > + if (pdev&& device_is_managed_by_native_pciehp(pdev))
    > + return AE_OK;
    >
    > acpi_evaluate_integer(handle, "_ADR", NULL,&adr);
    > device = (adr>> 16)& 0xffff;



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