Commit 437eb7bf authored by Lukas Wunner's avatar Lukas Wunner Committed by Bjorn Helgaas
Browse files

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: default avatarMika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: default avatarLukas Wunner <lukas@wunner.de>
Signed-off-by: default avatarBjorn Helgaas <bhelgaas@google.com>
Reviewed-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
parent 6ef13824

drivers/pci/hotplug/acpiphp_glue.c

+1 −27
Original line number Diff line number Diff line
@@ -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;

drivers/pci/pci-acpi.c

+24 −0
Original line number Diff line number Diff line
@@ -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.

include/linux/pci_hotplug.h

+2 −0
Original line number Diff line number Diff line
@@ -176,6 +176,7 @@ struct hotplug_params { 
#ifdef CONFIG_ACPI

#include <linux/acpi.h>

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

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