From 437eb7bf7b28472f8b7689e166dc1dd691367121 Mon Sep 17 00:00:00 2001 From: Lukas Wunner Date: Fri, 28 Oct 2016 10:52:06 +0200 Subject: [PATCH] ACPI / hotplug / PCI: Make device_is_managed_by_native_pciehp() public We're about to add runtime PM of hotplug ports, but we need to restrict it to ports that are handled natively by the OS: If they're handled by the firmware (which is the case for Thunderbolt on non-Macs), things would break if the OS put the ports into D3hot behind the firmware's back. To determine if a hotplug port is handled natively, one has to walk up from the port to the root bridge and check the cached _OSC Control Field for the value of the "PCI Express Native Hot Plug control" bit. There's already a function to do that, device_is_managed_by_native_pciehp(), but it's private to drivers/pci/hotplug/acpiphp_glue.c and only compiled in if CONFIG_HOTPLUG_PCI_ACPI is enabled. Make it public and move it to drivers/pci/pci-acpi.c, so that it is available in the more general CONFIG_ACPI case. The function contains a check if the device in question is a hotplug port and returns false if it's not. The caller we're going to add doesn't need this as it only calls the function if it actually *is* a hotplug port. Move the check out of the function into the single existing caller. Rename it to pciehp_is_native() and add some kerneldoc and polish. No functional change intended. Tested-by: Mika Westerberg Signed-off-by: Lukas Wunner Signed-off-by: Bjorn Helgaas Reviewed-by: Rafael J. Wysocki --- drivers/pci/hotplug/acpiphp_glue.c | 28 +--------------------------- drivers/pci/pci-acpi.c | 24 ++++++++++++++++++++++++ include/linux/pci_hotplug.h | 2 ++ 3 files changed, 27 insertions(+), 27 deletions(-) diff --git a/drivers/pci/hotplug/acpiphp_glue.c b/drivers/pci/hotplug/acpiphp_glue.c index b286a56e84b3..5ed2dcaa8e27 100644 --- a/drivers/pci/hotplug/acpiphp_glue.c +++ b/drivers/pci/hotplug/acpiphp_glue.c @@ -222,32 +222,6 @@ static void acpiphp_post_dock_fixup(struct acpi_device *adev) acpiphp_let_context_go(context); } -/* Check whether the PCI device is managed by native PCIe hotplug driver */ -static bool device_is_managed_by_native_pciehp(struct pci_dev *pdev) -{ - acpi_handle tmp; - struct acpi_pci_root *root; - - /* Check whether the PCIe port supports native PCIe hotplug */ - if (!pdev->is_hotplug_bridge) - 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; -} - /** * acpiphp_add_context - Add ACPIPHP context to an ACPI device object. * @handle: ACPI handle of the object to add a context to. @@ -331,7 +305,7 @@ static acpi_status acpiphp_add_context(acpi_handle handle, u32 lvl, void *data, * expose slots to user space in those cases. */ if ((acpi_pci_check_ejectable(pbus, handle) || is_dock_device(adev)) - && !(pdev && device_is_managed_by_native_pciehp(pdev))) { + && !(pdev && pdev->is_hotplug_bridge && pciehp_is_native(pdev))) { unsigned long long sun; int retval; diff --git a/drivers/pci/pci-acpi.c b/drivers/pci/pci-acpi.c index d966d47c9e80..ed3daa8e7658 100644 --- a/drivers/pci/pci-acpi.c +++ b/drivers/pci/pci-acpi.c @@ -293,6 +293,30 @@ int pci_get_hp_params(struct pci_dev *dev, struct hotplug_params *hpp) } EXPORT_SYMBOL_GPL(pci_get_hp_params); +/** + * pciehp_is_native - Check whether a hotplug port is handled by the OS + * @pdev: Hotplug port to check + * + * Walk up from @pdev to the host bridge, obtain its cached _OSC Control Field + * and return the value of the "PCI Express Native Hot Plug control" bit. + * On failure to obtain the _OSC Control Field return %false. + */ +bool pciehp_is_native(struct pci_dev *pdev) +{ + struct acpi_pci_root *root; + acpi_handle handle; + + handle = acpi_find_root_bridge_handle(pdev); + if (!handle) + return false; + + root = acpi_pci_find_root(handle); + if (!root) + return false; + + return root->osc_control_set & OSC_PCI_EXPRESS_NATIVE_HP_CONTROL; +} + /** * pci_acpi_wake_bus - Root bus wakeup notification fork function. * @work: Work item to handle. diff --git a/include/linux/pci_hotplug.h b/include/linux/pci_hotplug.h index 8c7895061121..2e855afa0212 100644 --- a/include/linux/pci_hotplug.h +++ b/include/linux/pci_hotplug.h @@ -176,6 +176,7 @@ struct hotplug_params { #ifdef CONFIG_ACPI #include int pci_get_hp_params(struct pci_dev *dev, struct hotplug_params *hpp); +bool pciehp_is_native(struct pci_dev *pdev); int acpi_get_hp_hw_control_from_firmware(struct pci_dev *dev, u32 flags); int acpi_pci_check_ejectable(struct pci_bus *pbus, acpi_handle handle); int acpi_pci_detect_ejectable(acpi_handle handle); @@ -185,5 +186,6 @@ static inline int pci_get_hp_params(struct pci_dev *dev, { return -ENODEV; } +static inline bool pciehp_is_native(struct pci_dev *pdev) { return true; } #endif #endif -- 2.45.2