Merge branch 'pci/hotplug'

- Detect if a device was removed or replaced during system sleep so we
  don't assume a new device is the one that used to be there.  This uses
  Vendor/Device/Subsystem/Class/Revision and Device Serial Number (if
  implemented), so it's not fool-proof and drivers may know how to detect
  more cases (Lukas Wunner)

- Add missing MODULE_DESCRIPTION() macro (Jeff Johnson)

* pci/hotplug:
  PCI: acpiphp: Add missing MODULE_DESCRIPTION() macro
  PCI: pciehp: Detect device replacement during system sleep

Author: bjorn-helgaas

drivers/pci/hotplug/acpiphp_ampere_altra.c

@@ -124,4 +124,5 @@ static struct platform_driver altra_led_driver = {
 module_platform_driver(altra_led_driver);
 
 MODULE_AUTHOR("D Scott Phillips <scott@os.amperecomputing.com>");
+MODULE_DESCRIPTION("ACPI PCI Hot Plug Extension for Ampere Altra");
 MODULE_LICENSE("GPL");

drivers/pci/hotplug/pciehp.h

@@ -46,6 +46,9 @@ extern int pciehp_poll_time;
 /**
  * struct controller - PCIe hotplug controller
  * @pcie: pointer to the controller's PCIe port service device
+ * @dsn: cached copy of Device Serial Number of Function 0 in the hotplug slot
+ *	(PCIe r6.2 sec 7.9.3); used to determine whether a hotplugged device
+ *	was replaced with a different one during system sleep
  * @slot_cap: cached copy of the Slot Capabilities register
  * @inband_presence_disabled: In-Band Presence Detect Disable supported by
  *	controller and disabled per spec recommendation (PCIe r5.0, appendix I
@@ -87,6 +90,7 @@ extern int pciehp_poll_time;
  */
 struct controller {
 	struct pcie_device *pcie;
+	u64 dsn;
 
 	u32 slot_cap;				/* capabilities and quirks */
 	unsigned int inband_presence_disabled:1;

drivers/pci/hotplug/pciehp_core.c

@@ -284,6 +284,32 @@ static int pciehp_suspend(struct pcie_device *dev)
 	return 0;
 }
 
+static bool pciehp_device_replaced(struct controller *ctrl)
+{
+	struct pci_dev *pdev __free(pci_dev_put);
+	u32 reg;
+
+	pdev = pci_get_slot(ctrl->pcie->port->subordinate, PCI_DEVFN(0, 0));
+	if (!pdev)
+		return true;
+
+	if (pci_read_config_dword(pdev, PCI_VENDOR_ID, &reg) ||
+	    reg != (pdev->vendor | (pdev->device << 16)) ||
+	    pci_read_config_dword(pdev, PCI_CLASS_REVISION, &reg) ||
+	    reg != (pdev->revision | (pdev->class << 8)))
+		return true;
+
+	if (pdev->hdr_type == PCI_HEADER_TYPE_NORMAL &&
+	    (pci_read_config_dword(pdev, PCI_SUBSYSTEM_VENDOR_ID, &reg) ||
+	     reg != (pdev->subsystem_vendor | (pdev->subsystem_device << 16))))
+		return true;
+
+	if (pci_get_dsn(pdev) != ctrl->dsn)
+		return true;
+
+	return false;
+}
+
 static int pciehp_resume_noirq(struct pcie_device *dev)
 {
 	struct controller *ctrl = get_service_data(dev);
@@ -293,9 +319,23 @@ static int pciehp_resume_noirq(struct pcie_device *dev)
 	ctrl->cmd_busy = true;
 
 	/* clear spurious events from rediscovery of inserted card */
-	if (ctrl->state == ON_STATE || ctrl->state == BLINKINGOFF_STATE)
+	if (ctrl->state == ON_STATE || ctrl->state == BLINKINGOFF_STATE) {
 		pcie_clear_hotplug_events(ctrl);
 
+		/*
+		 * If hotplugged device was replaced with a different one
+		 * during system sleep, mark the old device disconnected
+		 * (to prevent its driver from accessing the new device)
+		 * and synthesize a Presence Detect Changed event.
+		 */
+		if (pciehp_device_replaced(ctrl)) {
+			ctrl_dbg(ctrl, "device replaced during system sleep\n");
+			pci_walk_bus(ctrl->pcie->port->subordinate,
+				     pci_dev_set_disconnected, NULL);
+			pciehp_request(ctrl, PCI_EXP_SLTSTA_PDC);
+		}
+	}
+
 	return 0;
 }
 #endif

drivers/pci/hotplug/pciehp_hpc.c

@@ -1055,6 +1055,11 @@ struct controller *pcie_init(struct pcie_device *dev)
 		}
 	}
 
+	pdev = pci_get_slot(subordinate, PCI_DEVFN(0, 0));
+	if (pdev)
+		ctrl->dsn = pci_get_dsn(pdev);
+	pci_dev_put(pdev);
+
 	return ctrl;
 }
 

drivers/pci/hotplug/pciehp_pci.c

@@ -72,6 +72,10 @@ int pciehp_configure_device(struct controller *ctrl)
 	pci_bus_add_devices(parent);
 	down_read_nested(&ctrl->reset_lock, ctrl->depth);
 
+	dev = pci_get_slot(parent, PCI_DEVFN(0, 0));
+	ctrl->dsn = pci_get_dsn(dev);
+	pci_dev_put(dev);
+
  out:
 	pci_unlock_rescan_remove();
 	return ret;