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ACPI / hotplug / PCI: Make device_is_managed_by_native_pciehp() public

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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 <mika.westerberg@linux.intel.com>
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
This commit is contained in:
Lukas Wunner 2016-10-28 10:52:06 +02:00 committed by Bjorn Helgaas
parent 6ef13824e0
commit 437eb7bf7b
3 changed files with 27 additions and 27 deletions
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28
drivers/pci/hotplug/acpiphp_glue.c
View file

@ -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;

24
drivers/pci/pci-acpi.c
View file

@ -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.

2
include/linux/pci_hotplug.h
View file

@ -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