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.
Give the function a shorter name and add some kerneldoc and polish.
No functional change intended.
Tested-by: Mika Westerberg <mika.westerberg@xxxxxxxxxxxxxxx>
Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
Signed-off-by: Lukas Wunner <lukas@xxxxxxxxx>
---
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 b286a56..5ed2dca 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 d966d47..ed3daa8 100644
--- a/drivers/pci/pci-acpi.c
+++ b/drivers/pci/pci-acpi.c
@@ -294,6 +294,30 @@ 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 8c78950..2e855af 100644
--- a/include/linux/pci_hotplug.h
+++ b/include/linux/pci_hotplug.h
@@ -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
--
2.9.3
--
To unsubscribe from this list: send the line "unsubscribe linux-pci" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
