PCI: acpiphp: Do not use ACPI PCI subdriver mechanism

Previously the acpiphp driver registered itself as an ACPI PCI subdriver,
so its callbacks were invoked when creating/destroying PCI root
buses to manage ACPI-based PCI hotplug slots.  But it doesn't handle
P2P bridge hotplug events, so it will cause strange behaviour if there
are hotplug slots associated with a hot-removed P2P bridge.

This patch fixes this issue by:
1) Directly hooking into PCI core to update hotplug slot devices when
   creating/destroying PCI buses through:
	pci_{add|remove}_bus() -> acpi_pci_{add|remove}_bus()
2) Getting rid of unused ACPI PCI subdriver-related code

It also cleans up unused code in the acpiphp driver.

[bhelgaas: keep acpi_pci_add_bus() stub for CONFIG_ACPI=n]
Signed-off-by: Jiang Liu <jiang.liu@huawei.com>
Signed-off-by: Yijing Wang <wangyijing@huawei.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Yinghai Lu <yinghai@kernel.org>
Cc: "Rafael J. Wysocki" <rafael.j.wysocki@intel.com>
Cc: Toshi Kani <toshi.kani@hp.com>

3 files changed, 57 insertions, 247 deletions

diff --git a/drivers/pci/hotplug/acpiphp.h b/drivers/pci/hotplug/acpiphp.h
index b06ae681d5b7..abd48d309ad0 100644
--- a/drivers/pci/hotplug/acpiphp.h
+++ b/drivers/pci/hotplug/acpiphp.h
@@ -119,7 +119,6 @@ struct acpiphp_slot {
  */
 struct acpiphp_func {
         struct acpiphp_slot *slot;      /* parent */
-        struct acpiphp_bridge *bridge;  /* Ejectable PCI-to-PCI bridge */
 
         struct list_head sibling;
         struct notifier_block nb;
@@ -176,8 +175,6 @@ extern int acpiphp_register_hotplug_slot(struct acpiphp_slot *slot);
 extern void acpiphp_unregister_hotplug_slot(struct acpiphp_slot *slot);
 
 /* acpiphp_glue.c */
-extern int acpiphp_glue_init (void);
-extern void acpiphp_glue_exit (void);
 typedef int (*acpiphp_callback)(struct acpiphp_slot *slot, void *data);
 
 extern int acpiphp_enable_slot (struct acpiphp_slot *slot);
diff --git a/drivers/pci/hotplug/acpiphp_core.c b/drivers/pci/hotplug/acpiphp_core.c
index 81adbfa4df1b..ca8127950fcd 100644
--- a/drivers/pci/hotplug/acpiphp_core.c
+++ b/drivers/pci/hotplug/acpiphp_core.c
@@ -37,6 +37,7 @@
 
 #include <linux/kernel.h>
 #include <linux/pci.h>
+#include <linux/pci-acpi.h>
 #include <linux/pci_hotplug.h>
 #include <linux/slab.h>
 #include <linux/smp.h>
@@ -354,19 +355,9 @@ void acpiphp_unregister_hotplug_slot(struct acpiphp_slot *acpiphp_slot)
 }
 
 
-static int __init acpiphp_init(void)
+void __init acpiphp_init(void)
 {
         info(DRIVER_DESC " version: " DRIVER_VERSION "%s\n",
                 acpiphp_disabled ? ", disabled by user; please report a bug"
                                  : "");
-
-        if (acpi_pci_disabled || acpiphp_disabled)
-                return 0;
-
-        /* read all the ACPI info from the system */
-        /* initialize internal data structure etc. */
-        return acpiphp_glue_init();
 }
-
-
-module_init(acpiphp_init);
diff --git a/drivers/pci/hotplug/acpiphp_glue.c b/drivers/pci/hotplug/acpiphp_glue.c
index 718464f8fd40..20db4d6564a8 100644
--- a/drivers/pci/hotplug/acpiphp_glue.c
+++ b/drivers/pci/hotplug/acpiphp_glue.c
@@ -157,6 +157,7 @@ register_slot(acpi_handle handle, u32 lvl, void *context, void **rv)
         int device, function, retval;
         struct pci_bus *pbus = bridge->pci_bus;
         struct pci_dev *pdev;
+        u32 val;
 
         if (!acpi_pci_check_ejectable(pbus, handle) && !is_dock_device(handle))
                 return AE_OK;
@@ -249,11 +250,9 @@ register_slot(acpi_handle handle, u32 lvl, void *context, void **rv)
         newfunc->slot = slot;
         list_add_tail(&newfunc->sibling, &slot->funcs);
 
-        pdev = pci_get_slot(pbus, PCI_DEVFN(device, function));
-        if (pdev) {
+        if (pci_bus_read_dev_vendor_id(pbus, PCI_DEVFN(device, function),
+                                       &val, 60*1000))
                 slot->flags |= (SLOT_ENABLED | SLOT_POWEREDON);
-                pci_dev_put(pdev);
-        }
 
         if (is_dock_device(handle)) {
                 /* we don't want to call this device's _EJ0
@@ -366,148 +365,6 @@ static struct acpiphp_func *acpiphp_bridge_handle_to_function(acpi_handle handle
 }
 
 
-static inline void config_p2p_bridge_flags(struct acpiphp_bridge *bridge)
-{
-        acpi_handle dummy_handle;
-        struct acpiphp_func *func;
-
-        if (ACPI_SUCCESS(acpi_get_handle(bridge->handle,
-                                        "_EJ0", &dummy_handle))) {
-                bridge->flags |= BRIDGE_HAS_EJ0;
-
-                dbg("found ejectable p2p bridge\n");
-
-                /* make link between PCI bridge and PCI function */
-                func = acpiphp_bridge_handle_to_function(bridge->handle);
-                if (!func)
-                        return;
-                bridge->func = func;
-                func->bridge = bridge;
-        }
-}
-
-
-/* allocate and initialize host bridge data structure */
-static void add_host_bridge(struct acpi_pci_root *root)
-{
-        struct acpiphp_bridge *bridge;
-        acpi_handle handle = root->device->handle;
-
-        bridge = kzalloc(sizeof(struct acpiphp_bridge), GFP_KERNEL);
-        if (bridge == NULL)
-                return;
-
-        bridge->handle = handle;
-
-        bridge->pci_bus = root->bus;
-
-        init_bridge_misc(bridge);
-}
-
-
-/* allocate and initialize PCI-to-PCI bridge data structure */
-static void add_p2p_bridge(acpi_handle *handle)
-{
-        struct acpiphp_bridge *bridge;
-
-        bridge = kzalloc(sizeof(struct acpiphp_bridge), GFP_KERNEL);
-        if (bridge == NULL) {
-                err("out of memory\n");
-                return;
-        }
-
-        bridge->handle = handle;
-        config_p2p_bridge_flags(bridge);
-
-        bridge->pci_dev = acpi_get_pci_dev(handle);
-        bridge->pci_bus = bridge->pci_dev->subordinate;
-        if (!bridge->pci_bus) {
-                err("This is not a PCI-to-PCI bridge!\n");
-                goto err;
-        }
-
-        /*
-         * Grab a ref to the subordinate PCI bus in case the bus is
-         * removed via PCI core logical hotplug. The ref pins the bus
-         * (which we access during module unload).
-         */
-        get_device(&bridge->pci_bus->dev);
-
-        init_bridge_misc(bridge);
-        return;
- err:
-        pci_dev_put(bridge->pci_dev);
-        kfree(bridge);
-        return;
-}
-
-
-/* callback routine to find P2P bridges */
-static acpi_status
-find_p2p_bridge(acpi_handle handle, u32 lvl, void *context, void **rv)
-{
-        acpi_status status;
-        struct pci_dev *dev;
-
-        dev = acpi_get_pci_dev(handle);
-        if (!dev || !dev->subordinate)
-                goto out;
-
-        /* check if this bridge has ejectable slots */
-        if ((detect_ejectable_slots(handle) > 0)) {
-                dbg("found PCI-to-PCI bridge at PCI %s\n", pci_name(dev));
-                add_p2p_bridge(handle);
-        }
-
-        /* search P2P bridges under this p2p bridge */
-        status = acpi_walk_namespace(ACPI_TYPE_DEVICE, handle, (u32)1,
-                                     find_p2p_bridge, NULL, NULL, NULL);
-        if (ACPI_FAILURE(status))
-                warn("find_p2p_bridge failed (error code = 0x%x)\n", status);
-
- out:
-        pci_dev_put(dev);
-        return AE_OK;
-}
-
-
-/* find hot-pluggable slots, and then find P2P bridge */
-static int add_bridge(struct acpi_pci_root *root)
-{
-        acpi_status status;
-        unsigned long long tmp;
-        acpi_handle dummy_handle;
-        acpi_handle handle = root->device->handle;
-
-        /* if the bridge doesn't have _STA, we assume it is always there */
-        status = acpi_get_handle(handle, "_STA", &dummy_handle);
-        if (ACPI_SUCCESS(status)) {
-                status = acpi_evaluate_integer(handle, "_STA", NULL, &tmp);
-                if (ACPI_FAILURE(status)) {
-                        dbg("%s: _STA evaluation failure\n", __func__);
-                        return 0;
-                }
-                if ((tmp & ACPI_STA_DEVICE_FUNCTIONING) == 0)
-                        /* don't register this object */
-                        return 0;
-        }
-
-        /* check if this bridge has ejectable slots */
-        if (detect_ejectable_slots(handle) > 0) {
-                dbg("found PCI host-bus bridge with hot-pluggable slots\n");
-                add_host_bridge(root);
-        }
-
-        /* search P2P bridges under this host bridge */
-        status = acpi_walk_namespace(ACPI_TYPE_DEVICE, handle, (u32)1,
-                                     find_p2p_bridge, NULL, NULL, NULL);
-
-        if (ACPI_FAILURE(status))
-                warn("find_p2p_bridge failed (error code = 0x%x)\n", status);
-
-        return 0;
-}
-
 static struct acpiphp_bridge *acpiphp_handle_to_bridge(acpi_handle handle)
 {
         struct acpiphp_bridge *bridge;
@@ -567,56 +424,12 @@ static void cleanup_bridge(struct acpiphp_bridge *bridge)
                 slot = next;
         }
 
-        /*
-         * Only P2P bridges have a pci_dev
-         */
-        if (bridge->pci_dev)
-                put_device(&bridge->pci_bus->dev);
-
+        put_device(&bridge->pci_bus->dev);
         pci_dev_put(bridge->pci_dev);
         list_del(&bridge->list);
         kfree(bridge);
 }
 
-static acpi_status
-cleanup_p2p_bridge(acpi_handle handle, u32 lvl, void *context, void **rv)
-{
-        struct acpiphp_bridge *bridge;
-
-        /* cleanup p2p bridges under this P2P bridge
-           in a depth-first manner */
-        acpi_walk_namespace(ACPI_TYPE_DEVICE, handle, (u32)1,
-                                cleanup_p2p_bridge, NULL, NULL, NULL);
-
-        bridge = acpiphp_handle_to_bridge(handle);
-        if (bridge)
-                cleanup_bridge(bridge);
-
-        return AE_OK;
-}
-
-static void remove_bridge(struct acpi_pci_root *root)
-{
-        struct acpiphp_bridge *bridge;
-        acpi_handle handle = root->device->handle;
-
-        /* cleanup p2p bridges under this host bridge
-           in a depth-first manner */
-        acpi_walk_namespace(ACPI_TYPE_DEVICE, handle,
-                                (u32)1, cleanup_p2p_bridge, NULL, NULL, NULL);
-
-        /*
-         * On root bridges with hotplug slots directly underneath (ie,
-         * no p2p bridge between), we call cleanup_bridge(). 
-         *
-         * The else clause cleans up root bridges that either had no
-         * hotplug slots at all, or had a p2p bridge underneath.
-         */
-        bridge = acpiphp_handle_to_bridge(handle);
-        if (bridge)
-                cleanup_bridge(bridge);
-}
-
 static int power_on_slot(struct acpiphp_slot *slot)
 {
         acpi_status status;
@@ -798,6 +611,7 @@ static void check_hotplug_bridge(struct acpiphp_slot *slot, struct pci_dev *dev)
                 }
         }
 }
+
 /**
  * enable_device - enable, configure a slot
  * @slot: slot to be enabled
@@ -812,7 +626,6 @@ static int __ref enable_device(struct acpiphp_slot *slot)
         struct acpiphp_func *func;
         int retval = 0;
         int num, max, pass;
-        acpi_status status;
 
         if (slot->flags & SLOT_ENABLED)
                 goto err_exit;
@@ -867,18 +680,6 @@ static int __ref enable_device(struct acpiphp_slot *slot)
                         slot->flags &= (~SLOT_ENABLED);
                         continue;
                 }
-
-                if (dev->hdr_type != PCI_HEADER_TYPE_BRIDGE &&
-                    dev->hdr_type != PCI_HEADER_TYPE_CARDBUS) {
-                        pci_dev_put(dev);
-                        continue;
-                }
-
-                status = find_p2p_bridge(func->handle, (u32)1, bus, NULL);
-                if (ACPI_FAILURE(status))
-                        warn("find_p2p_bridge failed (error code = 0x%x)\n",
-                                status);
-                pci_dev_put(dev);
         }
 
 
@@ -912,16 +713,6 @@ static int disable_device(struct acpiphp_slot *slot)
 {
         struct acpiphp_func *func;
         struct pci_dev *pdev;
-        struct pci_bus *bus = slot->bridge->pci_bus;
-
-        list_for_each_entry(func, &slot->funcs, sibling) {
-                if (func->bridge) {
-                        /* cleanup p2p bridges under this P2P bridge */
-                        cleanup_p2p_bridge(func->bridge->handle,
-                                                (u32)1, NULL, NULL);
-                        func->bridge = NULL;
-                }
-        }
 
         /*
          * enable_device() enumerates all functions in this device via
@@ -940,7 +731,6 @@ static int disable_device(struct acpiphp_slot *slot)
 
         slot->flags &= (~SLOT_ENABLED);
 
-err_exit:
         return 0;
 }
 
@@ -1287,30 +1077,62 @@ static void handle_hotplug_event_func(acpi_handle handle, u32 type,
         alloc_acpi_hp_work(handle, type, context, _handle_hotplug_event_func);
 }
 
-static struct acpi_pci_driver acpi_pci_hp_driver = {
-        .add =          add_bridge,
-        .remove =       remove_bridge,
-};
-
-/**
- * acpiphp_glue_init - initializes all PCI hotplug - ACPI glue data structures
+/*
+ * Create hotplug slots for the PCI bus.
+ * It should always return 0 to avoid skipping following notifiers.
  */
-int __init acpiphp_glue_init(void)
+void acpiphp_enumerate_slots(struct pci_bus *bus, acpi_handle handle)
 {
-        acpi_pci_register_driver(&acpi_pci_hp_driver);
+        acpi_handle dummy_handle;
+        struct acpiphp_bridge *bridge;
 
-        return 0;
-}
+        if (acpiphp_disabled)
+                return;
 
+        if (detect_ejectable_slots(handle) <= 0)
+                return;
 
-/**
- * acpiphp_glue_exit - terminates all PCI hotplug - ACPI glue data structures
- *
- * This function frees all data allocated in acpiphp_glue_init().
- */
-void  acpiphp_glue_exit(void)
+        bridge = kzalloc(sizeof(struct acpiphp_bridge), GFP_KERNEL);
+        if (bridge == NULL) {
+                err("out of memory\n");
+                return;
+        }
+
+        bridge->handle = handle;
+        bridge->pci_dev = pci_dev_get(bus->self);
+        bridge->pci_bus = bus;
+
+        /*
+         * Grab a ref to the subordinate PCI bus in case the bus is
+         * removed via PCI core logical hotplug. The ref pins the bus
+         * (which we access during module unload).
+         */
+        get_device(&bus->dev);
+
+        if (!pci_is_root_bus(bridge->pci_bus) &&
+            ACPI_SUCCESS(acpi_get_handle(bridge->handle,
+                                        "_EJ0", &dummy_handle))) {
+                dbg("found ejectable p2p bridge\n");
+                bridge->flags |= BRIDGE_HAS_EJ0;
+                bridge->func = acpiphp_bridge_handle_to_function(handle);
+        }
+
+        init_bridge_misc(bridge);
+}
+
+/* Destroy hotplug slots associated with the PCI bus */
+void acpiphp_remove_slots(struct pci_bus *bus)
 {
-        acpi_pci_unregister_driver(&acpi_pci_hp_driver);
+        struct acpiphp_bridge *bridge, *tmp;
+
+        if (acpiphp_disabled)
+                return;
+
+        list_for_each_entry_safe(bridge, tmp, &bridge_list, list)
+                if (bridge->pci_bus == bus) {
+                        cleanup_bridge(bridge);
+                        break;
+                }
 }
 
 /**