PCI hotplug: introduce functions for ACPI slot detection

Some ACPI related PCI hotplug code can be shared among PCI hotplug
drivers. This patch introduces the following functions in
drivers/pci/hotplug/acpi_pcihp.c to share the code, and changes
acpiphp and pciehp to use them.

- int acpi_pci_detect_ejectable(struct pci_bus *pbus)
This checks if the specified PCI bus has ejectable slots.

- int acpi_pci_check_ejectable(struct pci_bus *pbus, acpi_handle handle)
This checks if the specified handle is ejectable ACPI PCI slot. The
'pbus' parameter is needed to check if 'handle' is PCI related ACPI
object.

This patch also introduces the following inline function in
include/linux/pci-acpi.h, which is useful to get ACPI handle of the
PCI bridge from struct pci_bus of the bridge's secondary bus.

- static inline acpi_handle acpi_pci_get_bridge_handle(struct pci_bus *pbus)
This returns ACPI handle of the PCI bridge which generates PCI bus
specified by 'pbus'.

Signed-off-by: Kenji Kaneshige <[e-mail]>
Signed-off-by: Jesse Barnes <[e-mail]>

drivers/pci/hotplug/acpi_pcihp.c

···
 }
 EXPORT_SYMBOL_GPL(acpi_root_bridge);
 
+
+static int is_ejectable(acpi_handle handle)
+{
+	acpi_status status;
+	acpi_handle tmp;
+	unsigned long long removable;
+	status = acpi_get_handle(handle, "_ADR", &tmp);
+	if (ACPI_FAILURE(status))
+		return 0;
+	status = acpi_get_handle(handle, "_EJ0", &tmp);
+	if (ACPI_SUCCESS(status))
+		return 1;
+	status = acpi_evaluate_integer(handle, "_RMV", NULL, &removable);
+	if (ACPI_SUCCESS(status) && removable)
+		return 1;
+	return 0;
+}
+
+/**
+ * acpi_pcihp_check_ejectable - check if handle is ejectable ACPI PCI slot
+ * @pbus: the PCI bus of the PCI slot corresponding to 'handle'
+ * @handle: ACPI handle to check
+ *
+ * Return 1 if handle is ejectable PCI slot, 0 otherwise.
+ */
+int acpi_pci_check_ejectable(struct pci_bus *pbus, acpi_handle handle)
+{
+	acpi_handle bridge_handle, parent_handle;
+
+	if (!(bridge_handle = acpi_pci_get_bridge_handle(pbus)))
+		return 0;
+	if ((ACPI_FAILURE(acpi_get_parent(handle, &parent_handle))))
+		return 0;
+	if (bridge_handle != parent_handle)
+		return 0;
+	return is_ejectable(handle);
+}
+EXPORT_SYMBOL_GPL(acpi_pci_check_ejectable);
+
+static acpi_status
+check_hotplug(acpi_handle handle, u32 lvl, void *context, void **rv)
+{
+	int *found = (int *)context;
+	if (is_ejectable(handle)) {
+		*found = 1;
+		return AE_CTRL_TERMINATE;
+	}
+	return AE_OK;
+}
+
+/**
+ * acpi_pci_detect_ejectable - check if the PCI bus has ejectable slots
+ * @pbus - PCI bus to scan
+ *
+ * Returns 1 if the PCI bus has ACPI based ejectable slots, 0 otherwise.
+ */
+int acpi_pci_detect_ejectable(struct pci_bus *pbus)
+{
+	acpi_handle handle;
+	int found = 0;
+
+	if (!(handle = acpi_pci_get_bridge_handle(pbus)))
+		return 0;
+	acpi_walk_namespace(ACPI_TYPE_DEVICE, handle, (u32)1,
+			    check_hotplug, (void *)&found, NULL);
+	return found;
+}
+EXPORT_SYMBOL_GPL(acpi_pci_detect_ejectable);
+
 module_param(debug_acpi, bool, 0644);
 MODULE_PARM_DESC(debug_acpi, "Debugging mode for ACPI enabled or not");

drivers/pci/hotplug/acpiphp_glue.c

···
 #include <linux/kernel.h>
 #include <linux/pci.h>
 #include <linux/pci_hotplug.h>
+#include <linux/pci-acpi.h>
 #include <linux/mutex.h>
 
 #include "../pci.h"
···
 static void acpiphp_set_hpp_values(acpi_handle handle, struct pci_bus *bus);
 static void handle_hotplug_event_func(acpi_handle handle, u32 type, void *context);
 
-
-/*
- * initialization & terminatation routines
- */
-
-/**
- * is_ejectable - determine if a slot is ejectable
- * @handle: handle to acpi namespace
- *
- * Ejectable slot should satisfy at least these conditions:
- *
- *  1. has _ADR method
- *  2. has _EJ0 method or _RMV method
- *
- * optionally
- *
- *  1. has _STA method
- *  2. has _PS0 method
- *  3. has _PS3 method
- *  4. ..
- */
-static int is_ejectable(acpi_handle handle)
-{
-	acpi_status status;
-	acpi_handle tmp;
-	unsigned long long removable;
-
-	status = acpi_get_handle(handle, "_ADR", &tmp);
-	if (ACPI_FAILURE(status))
-		return 0;
-
-	status = acpi_get_handle(handle, "_EJ0", &tmp);
-	if (ACPI_SUCCESS(status))
-		return 1;
-
-	status = acpi_get_handle(handle, "_RMV", &tmp);
-	if (ACPI_SUCCESS(status)) {
-		status = acpi_evaluate_integer(handle, "_RMV", NULL,
-					       &removable);
-		if (ACPI_SUCCESS(status) && removable)
-			return 1;
-	}
-
-	return 0;
-}
-
-
-/* callback routine to check for the existence of ejectable slots */
-static acpi_status
-is_ejectable_slot(acpi_handle handle, u32 lvl, void *context, void **rv)
-{
-	int *count = (int *)context;
-
-	if (is_ejectable(handle)) {
-		(*count)++;
-		/* only one ejectable slot is enough */
-		return AE_CTRL_TERMINATE;
-	} else {
-		return AE_OK;
-	}
-}
-
 /* callback routine to check for the existence of a pci dock device */
 static acpi_status
 is_pci_dock_device(acpi_handle handle, u32 lvl, void *context, void **rv)
···
 		return AE_OK;
 	}
 }
-
-
-
 
 /*
  * the _DCK method can do funny things... and sometimes not
···
 	acpi_status status = AE_OK;
 	unsigned long long adr, sun;
 	int device, function, retval;
+	struct pci_bus *pbus = bridge->pci_bus;
 
-	if (!is_ejectable(handle) && !is_dock_device(handle))
+	if (!acpi_pci_check_ejectable(pbus, handle) && !is_dock_device(handle))
 		return AE_OK;
 
 	acpi_evaluate_integer(handle, "_ADR", NULL, &adr);
···
 		bridge->nr_slots++;
 
 		dbg("found ACPI PCI Hotplug slot %llu at PCI %04x:%02x:%02x\n",
-				slot->sun, pci_domain_nr(bridge->pci_bus),
-				bridge->pci_bus->number, slot->device);
+		    slot->sun, pci_domain_nr(pbus), pbus->number, device);
 		retval = acpiphp_register_hotplug_slot(slot);
 		if (retval) {
 			if (retval == -EBUSY)
···
 	list_add_tail(&newfunc->sibling, &slot->funcs);
 
 	/* associate corresponding pci_dev */
-	newfunc->pci_dev = pci_get_slot(bridge->pci_bus,
-					 PCI_DEVFN(device, function));
+	newfunc->pci_dev = pci_get_slot(pbus, PCI_DEVFN(device, function));
 	if (newfunc->pci_dev) {
 		slot->flags |= (SLOT_ENABLED | SLOT_POWEREDON);
 	}
···
 
 
 /* see if it's worth looking at this bridge */
-static int detect_ejectable_slots(acpi_handle *bridge_handle)
+static int detect_ejectable_slots(struct pci_bus *pbus)
 {
-	acpi_status status;
-	int count;
-
-	count = 0;
-
-	/* only check slots defined directly below bridge object */
-	status = acpi_walk_namespace(ACPI_TYPE_DEVICE, bridge_handle, (u32)1,
-				     is_ejectable_slot, (void *)&count, NULL);
-
-	/*
-	 * we also need to add this bridge if there is a dock bridge or
-	 * other pci device on a dock station (removable)
-	 */
-	if (!count)
-		status = acpi_walk_namespace(ACPI_TYPE_DEVICE, bridge_handle,
-				(u32)1, is_pci_dock_device, (void *)&count,
-				NULL);
-
-	return count;
+	int found = acpi_pci_detect_ejectable(pbus);
+	if (!found) {
+		acpi_handle bridge_handle = acpi_pci_get_bridge_handle(pbus);
+		acpi_walk_namespace(ACPI_TYPE_DEVICE, bridge_handle, (u32)1,
+				    is_pci_dock_device, (void *)&found, NULL);
+	}
+	return found;
 }
 
 
···
 		goto out;
 
 	/* check if this bridge has ejectable slots */
-	if ((detect_ejectable_slots(handle) > 0)) {
+	if ((detect_ejectable_slots(dev->subordinate) > 0)) {
 		dbg("found PCI-to-PCI bridge at PCI %s\n", pci_name(dev));
 		add_p2p_bridge(handle, dev);
 	}
···
 	}
 
 	/* check if this bridge has ejectable slots */
-	if (detect_ejectable_slots(handle) > 0) {
+	if (detect_ejectable_slots(pci_bus) > 0) {
 		dbg("found PCI host-bus bridge with hot-pluggable slots\n");
 		add_host_bridge(handle, pci_bus);
 	}

drivers/pci/hotplug/pciehp_acpi.c

···
  */
 
 #include <linux/acpi.h>
+#include <linux/pci.h>
+#include <linux/pci_hotplug.h>
 #include "pciehp.h"
 
 #define PCIEHP_DETECT_PCIE	(0)
···
 	 "  auto(default) - Auto select mode. Use acpi option if duplicate\n"
 	 "                  slot ids are found. Otherwise, use pcie option\n");
 
-static int is_ejectable(acpi_handle handle)
-{
-	acpi_status status;
-	acpi_handle tmp;
-	unsigned long long removable;
-	status = acpi_get_handle(handle, "_ADR", &tmp);
-	if (ACPI_FAILURE(status))
-		return 0;
-	status = acpi_get_handle(handle, "_EJ0", &tmp);
-	if (ACPI_SUCCESS(status))
-		return 1;
-	status = acpi_evaluate_integer(handle, "_RMV", NULL, &removable);
-	if (ACPI_SUCCESS(status) && removable)
-		return 1;
-	return 0;
-}
-
-static acpi_status
-check_hotplug(acpi_handle handle, u32 lvl, void *context, void **rv)
-{
-	int *found = (int *)context;
-	if (is_ejectable(handle)) {
-		*found = 1;
-		return AE_CTRL_TERMINATE;
-	}
-	return AE_OK;
-}
-
-static int pciehp_detect_acpi_slot(struct pci_bus *pbus)
-{
-	acpi_handle handle;
-	struct pci_dev *pdev = pbus->self;
-	int found = 0;
-
-	if (!pdev){
-		int seg = pci_domain_nr(pbus), busnr = pbus->number;
-		handle = acpi_get_pci_rootbridge_handle(seg, busnr);
-	} else
-		handle = DEVICE_ACPI_HANDLE(&(pdev->dev));
-
-	if (!handle)
-		return 0;
-
-	acpi_walk_namespace(ACPI_TYPE_DEVICE, handle, (u32)1,
-			    check_hotplug, (void *)&found, NULL);
-	return found;
-}
-
 int pciehp_acpi_slot_detection_check(struct pci_dev *dev)
 {
 	if (slot_detection_mode != PCIEHP_DETECT_ACPI)
 		return 0;
-	if (pciehp_detect_acpi_slot(dev->subordinate))
+	if (acpi_pci_detect_ejectable(dev->subordinate))
 		return 0;
 	return -ENODEV;
 }
···
 	u32 slot_cap;
 	struct slot *slot, *tmp;
 	struct pci_dev *pdev = dev->port;
+	struct pci_bus *pbus = pdev->subordinate;
 	if (!(slot = kzalloc(sizeof(*slot), GFP_KERNEL)))
 		return -ENOMEM;
 	/* Note: pciehp_detect_mode != PCIEHP_DETECT_ACPI here */
···
 			dup_slot_id++;
 	}
 	list_add_tail(&slot->slot_list, &dummy_slots);
-	if (!acpi_slot_detected && pciehp_detect_acpi_slot(pdev->subordinate))
+	if (!acpi_slot_detected && acpi_pci_detect_ejectable(pbus))
 		acpi_slot_detected = 1;
 	return -ENODEV;         /* dummy driver always returns error */
 }

include/linux/pci-acpi.h

···
 	return acpi_get_pci_rootbridge_handle(pci_domain_nr(pdev->bus),
 			pdev->bus->number);
 }
+
+static inline acpi_handle acpi_pci_get_bridge_handle(struct pci_bus *pbus)
+{
+	int seg = pci_domain_nr(pbus), busnr = pbus->number;
+	struct pci_dev *bridge = pbus->self;
+	if (bridge)
+		return DEVICE_ACPI_HANDLE(&(bridge->dev));
+	return acpi_get_pci_rootbridge_handle(seg, busnr);
+}
 #else
 #if !defined(AE_ERROR)
 typedef u32 		acpi_status;

include/linux/pci_hotplug.h

···
 				struct hotplug_params *hpp);
 int acpi_get_hp_hw_control_from_firmware(struct pci_dev *dev, u32 flags);
 int acpi_root_bridge(acpi_handle handle);
+int acpi_pci_check_ejectable(struct pci_bus *pbus, acpi_handle handle);
+int acpi_pci_detect_ejectable(struct pci_bus *pbus);
 #endif
 #endif