Re: [PATCH v13 3/5] PCI/ACPI: Tidy _OSC control bit checking

[Rafael J. Wysocki (Intel)]

On Sat, Sep 19, 2026 at 6:27 PM Kuppuswamy Sathyanarayanan
<sathyanarayanan.kuppuswamy@xxxxxxxxxxxxxxx> wrote:
>
> Add OSC_OWNER() helper to prettify checking the _OSC control bits to learn
> whether the platform has granted us control of PCI features.  No functional
> change intended.
>
> [bhelgaas: split to separate patch, commit log]
> Signed-off-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@xxxxxxxxxxxxxxx>
> Signed-off-by: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>

Acked-by: Rafael J. Wysocki (Intel) <rafael@xxxxxxxxxx>

> ---
> Changes since v12
>
>  * Rebased to v7.3-rc3.  Parenthesized the OSC_OWNER() arguments, as
>    checkpatch --strict asks.
>  * Also convert native_cxl_error, which v12 left open coded.  Its bit comes
>    from the extended control word, so that word gets its own ext_ctrl
>    local.
>
> v12 posting
> https://lore.kernel.org/all/20201126011816.711106-1-helgaas@xxxxxxxxxx/
>
>  drivers/acpi/pci_root.c | 37 ++++++++++++++++++++++---------------
>  1 file changed, 22 insertions(+), 15 deletions(-)
>
> diff --git a/drivers/acpi/pci_root.c b/drivers/acpi/pci_root.c
> index 88c65f34e305..756dc2f055f5 100644
> --- a/drivers/acpi/pci_root.c
> +++ b/drivers/acpi/pci_root.c
> @@ -993,6 +993,12 @@ static void acpi_pci_root_release_info(struct pci_host_bridge *bridge)
>         __acpi_pci_root_release_info(bridge->release_data);
>  }
>
> +#define OSC_OWNER(ctrl, bit, flag)             \
> +       do {                                    \
> +               if (!((ctrl) & (bit)))          \
> +                       flag = 0;               \
> +       } while (0)
> +
>  struct pci_bus *acpi_pci_root_create(struct acpi_pci_root *root,
>                                      struct acpi_pci_root_ops *ops,
>                                      struct acpi_pci_root_info *info,
> @@ -1003,6 +1009,7 @@ struct pci_bus *acpi_pci_root_create(struct acpi_pci_root *root,
>         int node = acpi_get_node(device->handle);
>         struct pci_bus *bus;
>         struct pci_host_bridge *host_bridge;
> +       u32 ctrl, ext_ctrl;
>
>         info->root = root;
>         info->bridge = device;
> @@ -1028,21 +1035,21 @@ struct pci_bus *acpi_pci_root_create(struct acpi_pci_root *root,
>                 goto out_release_info;
>
>         host_bridge = to_pci_host_bridge(bus->bridge);
> -       if (!(root->osc_control_set & OSC_PCI_EXPRESS_NATIVE_HP_CONTROL))
> -               host_bridge->native_pcie_hotplug = 0;
> -       if (!(root->osc_control_set & OSC_PCI_SHPC_NATIVE_HP_CONTROL))
> -               host_bridge->native_shpc_hotplug = 0;
> -       if (!(root->osc_control_set & OSC_PCI_EXPRESS_AER_CONTROL))
> -               host_bridge->native_aer = 0;
> -       if (!(root->osc_control_set & OSC_PCI_EXPRESS_PME_CONTROL))
> -               host_bridge->native_pme = 0;
> -       if (!(root->osc_control_set & OSC_PCI_EXPRESS_LTR_CONTROL))
> -               host_bridge->native_ltr = 0;
> -       if (!(root->osc_control_set & OSC_PCI_EXPRESS_DPC_CONTROL))
> -               host_bridge->native_dpc = 0;
> -
> -       if (!(root->osc_ext_control_set & OSC_CXL_ERROR_REPORTING_CONTROL))
> -               host_bridge->native_cxl_error = 0;
> +
> +       ctrl = root->osc_control_set;
> +       ext_ctrl = root->osc_ext_control_set;
> +
> +       OSC_OWNER(ctrl, OSC_PCI_EXPRESS_NATIVE_HP_CONTROL,
> +                 host_bridge->native_pcie_hotplug);
> +       OSC_OWNER(ctrl, OSC_PCI_SHPC_NATIVE_HP_CONTROL,
> +                 host_bridge->native_shpc_hotplug);
> +       OSC_OWNER(ctrl, OSC_PCI_EXPRESS_AER_CONTROL, host_bridge->native_aer);
> +       OSC_OWNER(ctrl, OSC_PCI_EXPRESS_PME_CONTROL, host_bridge->native_pme);
> +       OSC_OWNER(ctrl, OSC_PCI_EXPRESS_LTR_CONTROL, host_bridge->native_ltr);
> +       OSC_OWNER(ctrl, OSC_PCI_EXPRESS_DPC_CONTROL, host_bridge->native_dpc);
> +
> +       OSC_OWNER(ext_ctrl, OSC_CXL_ERROR_REPORTING_CONTROL,
> +                 host_bridge->native_cxl_error);
>
>         acpi_dev_power_up_children_with_adr(device);
>
> --
> 2.43.0
>