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* pci_slot.c - ACPI PCI Slot Driver
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* The code here is heavily leveraged from the acpiphp module.
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* Thanks to Matthew Wilcox <matthew@wil.cx> for much guidance.
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* Thanks to Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com> for code
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* Copyright (C) 2007-2008 Hewlett-Packard Development Company, L.P.
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* Alex Chiang <achiang@hp.com>
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* This program is free software; you can redistribute it and/or modify it
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* under the terms and conditions of the GNU General Public License,
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* version 2, as published by the Free Software Foundation.
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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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* You should have received a copy of the GNU General Public License along
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* with this program; if not, write to the Free Software Foundation, Inc.,
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* 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/init.h>
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#include <linux/slab.h>
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#include <linux/types.h>
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#include <linux/pci.h>
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#include <linux/acpi.h>
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#include <acpi/acpi_bus.h>
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#include <acpi/acpi_drivers.h>
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#include <linux/dmi.h>
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static int check_sta_before_sun;
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#define DRIVER_VERSION "0.1"
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#define DRIVER_AUTHOR "Alex Chiang <achiang@hp.com>"
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#define DRIVER_DESC "ACPI PCI Slot Detection Driver"
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MODULE_AUTHOR(DRIVER_AUTHOR);
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MODULE_DESCRIPTION(DRIVER_DESC);
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MODULE_LICENSE("GPL");
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MODULE_PARM_DESC(debug, "Debugging mode enabled or not");
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module_param(debug, bool, 0644);
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#define _COMPONENT ACPI_PCI_COMPONENT
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ACPI_MODULE_NAME("pci_slot");
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#define MY_NAME "pci_slot"
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#define err(format, arg...) printk(KERN_ERR "%s: " format , MY_NAME , ## arg)
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#define info(format, arg...) printk(KERN_INFO "%s: " format , MY_NAME , ## arg)
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#define dbg(format, arg...) \
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printk(KERN_DEBUG "%s: " format, \
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#define SLOT_NAME_SIZE 21 /* Inspired by #define in acpiphp.h */
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struct acpi_pci_slot {
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acpi_handle root_handle; /* handle of the root bridge */
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struct pci_slot *pci_slot; /* corresponding pci_slot */
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struct list_head list; /* node in the list of slots */
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static int acpi_pci_slot_add(acpi_handle handle);
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static void acpi_pci_slot_remove(acpi_handle handle);
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static LIST_HEAD(slot_list);
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static DEFINE_MUTEX(slot_list_lock);
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static struct acpi_pci_driver acpi_pci_slot_driver = {
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.add = acpi_pci_slot_add,
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.remove = acpi_pci_slot_remove,
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check_slot(acpi_handle handle, unsigned long long *sun)
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unsigned long long adr, sta;
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struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
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acpi_get_name(handle, ACPI_FULL_PATHNAME, &buffer);
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dbg("Checking slot on path: %s\n", (char *)buffer.pointer);
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if (check_sta_before_sun) {
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/* If SxFy doesn't have _STA, we just assume it's there */
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status = acpi_evaluate_integer(handle, "_STA", NULL, &sta);
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if (ACPI_SUCCESS(status) && !(sta & ACPI_STA_DEVICE_PRESENT))
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status = acpi_evaluate_integer(handle, "_ADR", NULL, &adr);
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if (ACPI_FAILURE(status)) {
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dbg("_ADR returned %d on %s\n", status, (char *)buffer.pointer);
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/* No _SUN == not a slot == bail */
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status = acpi_evaluate_integer(handle, "_SUN", NULL, sun);
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if (ACPI_FAILURE(status)) {
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dbg("_SUN returned %d on %s\n", status, (char *)buffer.pointer);
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device = (adr >> 16) & 0xffff;
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kfree(buffer.pointer);
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struct callback_args {
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acpi_walk_callback user_function; /* only for walk_p2p_bridge */
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struct pci_bus *pci_bus;
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acpi_handle root_handle;
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* Called once for each SxFy object in the namespace. Don't worry about
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* calling pci_create_slot multiple times for the same pci_bus:device,
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* since each subsequent call simply bumps the refcount on the pci_slot.
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* The number of calls to pci_destroy_slot from unregister_slot is
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register_slot(acpi_handle handle, u32 lvl, void *context, void **rv)
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unsigned long long sun;
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char name[SLOT_NAME_SIZE];
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struct acpi_pci_slot *slot;
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struct pci_slot *pci_slot;
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struct callback_args *parent_context = context;
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struct pci_bus *pci_bus = parent_context->pci_bus;
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device = check_slot(handle, &sun);
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slot = kmalloc(sizeof(*slot), GFP_KERNEL);
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err("%s: cannot allocate memory\n", __func__);
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snprintf(name, sizeof(name), "%llu", sun);
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pci_slot = pci_create_slot(pci_bus, device, name, NULL);
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if (IS_ERR(pci_slot)) {
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err("pci_create_slot returned %ld\n", PTR_ERR(pci_slot));
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slot->root_handle = parent_context->root_handle;
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slot->pci_slot = pci_slot;
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INIT_LIST_HEAD(&slot->list);
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mutex_lock(&slot_list_lock);
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list_add(&slot->list, &slot_list);
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mutex_unlock(&slot_list_lock);
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get_device(&pci_bus->dev);
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dbg("pci_slot: %p, pci_bus: %x, device: %d, name: %s\n",
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pci_slot, pci_bus->number, device, name);
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* walk_p2p_bridge - discover and walk p2p bridges
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* @handle: points to an acpi_pci_root
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* @context: p2p_bridge_context pointer
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* Note that when we call ourselves recursively, we pass a different
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* value of pci_bus in the child_context.
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walk_p2p_bridge(acpi_handle handle, u32 lvl, void *context, void **rv)
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int device, function;
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unsigned long long adr;
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acpi_handle dummy_handle;
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acpi_walk_callback user_function;
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struct pci_bus *pci_bus;
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struct callback_args child_context;
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struct callback_args *parent_context = context;
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pci_bus = parent_context->pci_bus;
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user_function = parent_context->user_function;
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status = acpi_get_handle(handle, "_ADR", &dummy_handle);
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if (ACPI_FAILURE(status))
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status = acpi_evaluate_integer(handle, "_ADR", NULL, &adr);
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if (ACPI_FAILURE(status))
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device = (adr >> 16) & 0xffff;
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function = adr & 0xffff;
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dev = pci_get_slot(pci_bus, PCI_DEVFN(device, function));
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if (!dev || !dev->subordinate)
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child_context.pci_bus = dev->subordinate;
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child_context.user_function = user_function;
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child_context.root_handle = parent_context->root_handle;
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dbg("p2p bridge walk, pci_bus = %x\n", dev->subordinate->number);
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status = acpi_walk_namespace(ACPI_TYPE_DEVICE, handle, (u32)1,
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user_function, NULL, &child_context, NULL);
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if (ACPI_FAILURE(status))
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status = acpi_walk_namespace(ACPI_TYPE_DEVICE, handle, (u32)1,
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walk_p2p_bridge, NULL, &child_context, NULL);
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* walk_root_bridge - generic root bridge walker
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* @handle: points to an acpi_pci_root
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* @user_function: user callback for slot objects
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* Call user_function for all objects underneath this root bridge.
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* Walk p2p bridges underneath us and call user_function on those too.
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walk_root_bridge(acpi_handle handle, acpi_walk_callback user_function)
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unsigned long long tmp;
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acpi_handle dummy_handle;
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struct pci_bus *pci_bus;
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struct callback_args context;
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/* If the bridge doesn't have _STA, we assume it is always there */
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status = acpi_get_handle(handle, "_STA", &dummy_handle);
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if (ACPI_SUCCESS(status)) {
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status = acpi_evaluate_integer(handle, "_STA", NULL, &tmp);
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if (ACPI_FAILURE(status)) {
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info("%s: _STA evaluation failure\n", __func__);
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if ((tmp & ACPI_STA_DEVICE_FUNCTIONING) == 0)
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/* don't register this object */
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status = acpi_evaluate_integer(handle, "_SEG", NULL, &tmp);
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seg = ACPI_SUCCESS(status) ? tmp : 0;
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status = acpi_evaluate_integer(handle, "_BBN", NULL, &tmp);
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bus = ACPI_SUCCESS(status) ? tmp : 0;
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pci_bus = pci_find_bus(seg, bus);
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context.pci_bus = pci_bus;
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context.user_function = user_function;
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context.root_handle = handle;
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dbg("root bridge walk, pci_bus = %x\n", pci_bus->number);
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status = acpi_walk_namespace(ACPI_TYPE_DEVICE, handle, (u32)1,
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user_function, NULL, &context, NULL);
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if (ACPI_FAILURE(status))
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status = acpi_walk_namespace(ACPI_TYPE_DEVICE, handle, (u32)1,
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walk_p2p_bridge, NULL, &context, NULL);
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if (ACPI_FAILURE(status))
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err("%s: walk_p2p_bridge failure - %d\n", __func__, status);
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* @handle: points to an acpi_pci_root
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acpi_pci_slot_add(acpi_handle handle)
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status = walk_root_bridge(handle, register_slot);
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if (ACPI_FAILURE(status))
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err("%s: register_slot failure - %d\n", __func__, status);
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* acpi_pci_slot_remove
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* @handle: points to an acpi_pci_root
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acpi_pci_slot_remove(acpi_handle handle)
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struct acpi_pci_slot *slot, *tmp;
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struct pci_bus *pbus;
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mutex_lock(&slot_list_lock);
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list_for_each_entry_safe(slot, tmp, &slot_list, list) {
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if (slot->root_handle == handle) {
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list_del(&slot->list);
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pbus = slot->pci_slot->bus;
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pci_destroy_slot(slot->pci_slot);
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put_device(&pbus->dev);
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mutex_unlock(&slot_list_lock);
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static int do_sta_before_sun(const struct dmi_system_id *d)
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info("%s detected: will evaluate _STA before calling _SUN\n", d->ident);
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check_sta_before_sun = 1;
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static struct dmi_system_id acpi_pci_slot_dmi_table[] __initdata = {
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* Fujitsu Primequest machines will return 1023 to indicate an
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* error if the _SUN method is evaluated on SxFy objects that
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* are not present (as indicated by _STA), so for those machines,
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* we want to check _STA before evaluating _SUN.
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.callback = do_sta_before_sun,
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.ident = "Fujitsu PRIMEQUEST",
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DMI_MATCH(DMI_BIOS_VENDOR, "FUJITSU LIMITED"),
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DMI_MATCH(DMI_BIOS_VERSION, "PRIMEQUEST"),
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acpi_pci_slot_init(void)
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dmi_check_system(acpi_pci_slot_dmi_table);
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acpi_pci_register_driver(&acpi_pci_slot_driver);
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acpi_pci_slot_exit(void)
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acpi_pci_unregister_driver(&acpi_pci_slot_driver);
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module_init(acpi_pci_slot_init);
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module_exit(acpi_pci_slot_exit);