PCI: shpchp: Request SHPC control via _OSC when adding host bridge

The SHPC driver now must be builtin (it cannot be a module).  If it is
present, request SHPC control immediately when adding the ACPI host bridge.
This is similar to how we handle native PCIe hotplug via pciehp.

Suggested-by: Bjorn Helgaas <bhelgaas@google.com>
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
[bhelgaas: split to separate patch]
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

3 files changed, 7 insertions, 0 deletions

diff --git a/drivers/acpi/pci_root.c b/drivers/acpi/pci_root.c
index 032a578da5d4..d9b8407ce4e8 100644
--- a/drivers/acpi/pci_root.c
+++ b/drivers/acpi/pci_root.c
@@ -477,6 +477,9 @@ static void negotiate_os_control(struct acpi_pci_root *root, int *no_aspm)
         if (IS_ENABLED(CONFIG_HOTPLUG_PCI_PCIE))
                 control |= OSC_PCI_EXPRESS_NATIVE_HP_CONTROL;
 
+        if (IS_ENABLED(CONFIG_HOTPLUG_PCI_SHPC))
+                control |= OSC_PCI_SHPC_NATIVE_HP_CONTROL;
+
         if (pci_aer_available()) {
                 if (aer_acpi_firmware_first())
                         dev_info(&device->dev,
@@ -903,6 +906,8 @@ struct pci_bus *acpi_pci_root_create(struct acpi_pci_root *root,
         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))
diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index eba2b17d2d80..91712b2ee2c6 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -553,6 +553,7 @@ struct pci_host_bridge *pci_alloc_host_bridge(size_t priv)
          */
         bridge->native_aer = 1;
         bridge->native_pcie_hotplug = 1;
+        bridge->native_shpc_hotplug = 1;
         bridge->native_pme = 1;
 
         return bridge;
diff --git a/include/linux/pci.h b/include/linux/pci.h
index 3f009003706a..a4968cdb5f33 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -475,6 +475,7 @@ struct pci_host_bridge {
         unsigned int    no_ext_tags:1;          /* No Extended Tags */
         unsigned int    native_aer:1;           /* OS may use PCIe AER */
         unsigned int    native_pcie_hotplug:1;  /* OS may use PCIe hotplug */
+        unsigned int    native_shpc_hotplug:1;  /* OS may use SHPC hotplug */
         unsigned int    native_pme:1;           /* OS may use PCIe PME */
         /* Resource alignment requirements */
         resource_size_t (*align_resource)(struct pci_dev *dev,