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* pci_link.c - ACPI PCI Interrupt Link Device Driver ($Revision: 34 $)
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* Copyright (C) 2001, 2002 Andy Grover <andrew.grover@intel.com>
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* Copyright (C) 2001, 2002 Paul Diefenbaugh <paul.s.diefenbaugh@intel.com>
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* Copyright (C) 2002 Dominik Brodowski <devel@brodo.de>
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* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or (at
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* your option) any later version.
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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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* 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
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* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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* 1. Support more than one IRQ resource entry per link device (index).
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* 2. Implement start/stop mechanism and use ACPI Bus Driver facilities
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* for IRQ management (e.g. start()->_SRS).
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#include <linux/syscore_ops.h>
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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/types.h>
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#include <linux/spinlock.h>
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#include <linux/pci.h>
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#include <linux/mutex.h>
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#include <linux/slab.h>
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#include <acpi/acpi_bus.h>
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#include <acpi/acpi_drivers.h>
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#define PREFIX "ACPI: "
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#define _COMPONENT ACPI_PCI_COMPONENT
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ACPI_MODULE_NAME("pci_link");
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#define ACPI_PCI_LINK_CLASS "pci_irq_routing"
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#define ACPI_PCI_LINK_DEVICE_NAME "PCI Interrupt Link"
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#define ACPI_PCI_LINK_FILE_INFO "info"
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#define ACPI_PCI_LINK_FILE_STATUS "state"
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#define ACPI_PCI_LINK_MAX_POSSIBLE 16
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static int acpi_pci_link_add(struct acpi_device *device);
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static int acpi_pci_link_remove(struct acpi_device *device, int type);
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static const struct acpi_device_id link_device_ids[] = {
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MODULE_DEVICE_TABLE(acpi, link_device_ids);
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static struct acpi_driver acpi_pci_link_driver = {
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.class = ACPI_PCI_LINK_CLASS,
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.ids = link_device_ids,
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.add = acpi_pci_link_add,
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.remove = acpi_pci_link_remove,
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* If a link is initialized, we never change its active and initialized
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* later even the link is disable. Instead, we just repick the active irq
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struct acpi_pci_link_irq {
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u8 active; /* Current IRQ */
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u8 triggering; /* All IRQs */
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u8 polarity; /* All IRQs */
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u8 possible[ACPI_PCI_LINK_MAX_POSSIBLE];
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struct acpi_pci_link {
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struct list_head list;
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struct acpi_device *device;
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struct acpi_pci_link_irq irq;
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static LIST_HEAD(acpi_link_list);
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static DEFINE_MUTEX(acpi_link_lock);
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/* --------------------------------------------------------------------------
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PCI Link Device Management
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-------------------------------------------------------------------------- */
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* set context (link) possible list from resource list
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static acpi_status acpi_pci_link_check_possible(struct acpi_resource *resource,
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struct acpi_pci_link *link = context;
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switch (resource->type) {
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case ACPI_RESOURCE_TYPE_START_DEPENDENT:
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case ACPI_RESOURCE_TYPE_END_TAG:
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case ACPI_RESOURCE_TYPE_IRQ:
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struct acpi_resource_irq *p = &resource->data.irq;
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if (!p || !p->interrupt_count) {
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ACPI_DEBUG_PRINT((ACPI_DB_INFO,
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"Blank _PRS IRQ resource\n"));
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(i < p->interrupt_count
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&& i < ACPI_PCI_LINK_MAX_POSSIBLE); i++) {
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if (!p->interrupts[i]) {
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printk(KERN_WARNING PREFIX
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"Invalid _PRS IRQ %d\n",
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link->irq.possible[i] = p->interrupts[i];
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link->irq.possible_count++;
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link->irq.triggering = p->triggering;
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link->irq.polarity = p->polarity;
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link->irq.resource_type = ACPI_RESOURCE_TYPE_IRQ;
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case ACPI_RESOURCE_TYPE_EXTENDED_IRQ:
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struct acpi_resource_extended_irq *p =
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&resource->data.extended_irq;
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if (!p || !p->interrupt_count) {
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printk(KERN_WARNING PREFIX
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"Blank _PRS EXT IRQ resource\n");
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(i < p->interrupt_count
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&& i < ACPI_PCI_LINK_MAX_POSSIBLE); i++) {
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if (!p->interrupts[i]) {
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printk(KERN_WARNING PREFIX
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"Invalid _PRS IRQ %d\n",
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link->irq.possible[i] = p->interrupts[i];
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link->irq.possible_count++;
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link->irq.triggering = p->triggering;
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link->irq.polarity = p->polarity;
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link->irq.resource_type = ACPI_RESOURCE_TYPE_EXTENDED_IRQ;
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printk(KERN_ERR PREFIX "_PRS resource type 0x%x isn't an IRQ\n",
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return AE_CTRL_TERMINATE;
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static int acpi_pci_link_get_possible(struct acpi_pci_link *link)
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status = acpi_walk_resources(link->device->handle, METHOD_NAME__PRS,
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acpi_pci_link_check_possible, link);
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if (ACPI_FAILURE(status)) {
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ACPI_EXCEPTION((AE_INFO, status, "Evaluating _PRS"));
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ACPI_DEBUG_PRINT((ACPI_DB_INFO,
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"Found %d possible IRQs\n",
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link->irq.possible_count));
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static acpi_status acpi_pci_link_check_current(struct acpi_resource *resource,
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switch (resource->type) {
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case ACPI_RESOURCE_TYPE_START_DEPENDENT:
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case ACPI_RESOURCE_TYPE_END_TAG:
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case ACPI_RESOURCE_TYPE_IRQ:
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struct acpi_resource_irq *p = &resource->data.irq;
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if (!p || !p->interrupt_count) {
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* IRQ descriptors may have no IRQ# bits set,
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* particularly those those w/ _STA disabled
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ACPI_DEBUG_PRINT((ACPI_DB_INFO,
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"Blank _CRS IRQ resource\n"));
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*irq = p->interrupts[0];
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case ACPI_RESOURCE_TYPE_EXTENDED_IRQ:
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struct acpi_resource_extended_irq *p =
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&resource->data.extended_irq;
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if (!p || !p->interrupt_count) {
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* extended IRQ descriptors must
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* return at least 1 IRQ
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printk(KERN_WARNING PREFIX
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"Blank _CRS EXT IRQ resource\n");
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*irq = p->interrupts[0];
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printk(KERN_ERR PREFIX "_CRS resource type 0x%x isn't an IRQ\n",
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return AE_CTRL_TERMINATE;
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* Run _CRS and set link->irq.active
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static int acpi_pci_link_get_current(struct acpi_pci_link *link)
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link->irq.active = 0;
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/* in practice, status disabled is meaningless, ignore it */
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/* Query _STA, set link->device->status */
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result = acpi_bus_get_status(link->device);
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printk(KERN_ERR PREFIX "Unable to read status\n");
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if (!link->device->status.enabled) {
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ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Link disabled\n"));
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* Query and parse _CRS to get the current IRQ assignment.
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status = acpi_walk_resources(link->device->handle, METHOD_NAME__CRS,
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acpi_pci_link_check_current, &irq);
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if (ACPI_FAILURE(status)) {
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ACPI_EXCEPTION((AE_INFO, status, "Evaluating _CRS"));
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if (acpi_strict && !irq) {
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printk(KERN_ERR PREFIX "_CRS returned 0\n");
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link->irq.active = irq;
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ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Link at IRQ %d \n", link->irq.active));
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static int acpi_pci_link_set(struct acpi_pci_link *link, int irq)
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struct acpi_resource res;
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struct acpi_resource end;
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struct acpi_buffer buffer = { 0, NULL };
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resource = kzalloc(sizeof(*resource) + 1, irqs_disabled() ? GFP_ATOMIC: GFP_KERNEL);
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buffer.length = sizeof(*resource) + 1;
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buffer.pointer = resource;
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switch (link->irq.resource_type) {
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case ACPI_RESOURCE_TYPE_IRQ:
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resource->res.type = ACPI_RESOURCE_TYPE_IRQ;
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resource->res.length = sizeof(struct acpi_resource);
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resource->res.data.irq.triggering = link->irq.triggering;
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resource->res.data.irq.polarity =
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if (link->irq.triggering == ACPI_EDGE_SENSITIVE)
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resource->res.data.irq.sharable =
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resource->res.data.irq.sharable = ACPI_SHARED;
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resource->res.data.irq.interrupt_count = 1;
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resource->res.data.irq.interrupts[0] = irq;
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case ACPI_RESOURCE_TYPE_EXTENDED_IRQ:
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resource->res.type = ACPI_RESOURCE_TYPE_EXTENDED_IRQ;
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resource->res.length = sizeof(struct acpi_resource);
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resource->res.data.extended_irq.producer_consumer =
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resource->res.data.extended_irq.triggering =
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link->irq.triggering;
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resource->res.data.extended_irq.polarity =
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if (link->irq.triggering == ACPI_EDGE_SENSITIVE)
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resource->res.data.irq.sharable =
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resource->res.data.irq.sharable = ACPI_SHARED;
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resource->res.data.extended_irq.interrupt_count = 1;
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resource->res.data.extended_irq.interrupts[0] = irq;
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/* ignore resource_source, it's optional */
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printk(KERN_ERR PREFIX "Invalid Resource_type %d\n", link->irq.resource_type);
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resource->end.type = ACPI_RESOURCE_TYPE_END_TAG;
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/* Attempt to set the resource */
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status = acpi_set_current_resources(link->device->handle, &buffer);
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/* check for total failure */
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if (ACPI_FAILURE(status)) {
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ACPI_EXCEPTION((AE_INFO, status, "Evaluating _SRS"));
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/* Query _STA, set device->status */
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result = acpi_bus_get_status(link->device);
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printk(KERN_ERR PREFIX "Unable to read status\n");
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if (!link->device->status.enabled) {
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printk(KERN_WARNING PREFIX
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"%s [%s] disabled and referenced, BIOS bug\n",
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acpi_device_name(link->device),
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acpi_device_bid(link->device));
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/* Query _CRS, set link->irq.active */
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result = acpi_pci_link_get_current(link);
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* Is current setting not what we set?
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* set link->irq.active
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if (link->irq.active != irq) {
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* policy: when _CRS doesn't return what we just _SRS
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* assume _SRS worked and override _CRS value.
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printk(KERN_WARNING PREFIX
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"%s [%s] BIOS reported IRQ %d, using IRQ %d\n",
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acpi_device_name(link->device),
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acpi_device_bid(link->device), link->irq.active, irq);
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link->irq.active = irq;
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ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Set IRQ %d\n", link->irq.active));
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/* --------------------------------------------------------------------------
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PCI Link IRQ Management
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-------------------------------------------------------------------------- */
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* "acpi_irq_balance" (default in APIC mode) enables ACPI to use PIC Interrupt
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* Link Devices to move the PIRQs around to minimize sharing.
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* "acpi_irq_nobalance" (default in PIC mode) tells ACPI not to move any PIC IRQs
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* that the BIOS has already set to active. This is necessary because
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* ACPI has no automatic means of knowing what ISA IRQs are used. Note that
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* if the BIOS doesn't set a Link Device active, ACPI needs to program it
426
* even if acpi_irq_nobalance is set.
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* A tables of penalties avoids directing PCI interrupts to well known
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* ISA IRQs. Boot params are available to over-ride the default table:
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* List interrupts that are free for PCI use.
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* List interrupts that should not be used for PCI:
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* Note that PCI IRQ routers have a list of possible IRQs,
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* which may not include the IRQs this table says are available.
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* Since this heuristic can't tell the difference between a link
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* that no device will attach to, vs. a link which may be shared
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* by multiple active devices -- it is not optimal.
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* If interrupt performance is that important, get an IO-APIC system
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* with a pin dedicated to each device. Or for that matter, an MSI
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#define ACPI_MAX_IRQS 256
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#define ACPI_MAX_ISA_IRQ 16
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#define PIRQ_PENALTY_PCI_AVAILABLE (0)
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#define PIRQ_PENALTY_PCI_POSSIBLE (16*16)
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#define PIRQ_PENALTY_PCI_USING (16*16*16)
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#define PIRQ_PENALTY_ISA_TYPICAL (16*16*16*16)
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#define PIRQ_PENALTY_ISA_USED (16*16*16*16*16)
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#define PIRQ_PENALTY_ISA_ALWAYS (16*16*16*16*16*16)
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static int acpi_irq_penalty[ACPI_MAX_IRQS] = {
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PIRQ_PENALTY_ISA_ALWAYS, /* IRQ0 timer */
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PIRQ_PENALTY_ISA_ALWAYS, /* IRQ1 keyboard */
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PIRQ_PENALTY_ISA_ALWAYS, /* IRQ2 cascade */
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PIRQ_PENALTY_ISA_TYPICAL, /* IRQ3 serial */
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PIRQ_PENALTY_ISA_TYPICAL, /* IRQ4 serial */
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PIRQ_PENALTY_ISA_TYPICAL, /* IRQ5 sometimes SoundBlaster */
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PIRQ_PENALTY_ISA_TYPICAL, /* IRQ6 */
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PIRQ_PENALTY_ISA_TYPICAL, /* IRQ7 parallel, spurious */
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PIRQ_PENALTY_ISA_TYPICAL, /* IRQ8 rtc, sometimes */
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PIRQ_PENALTY_PCI_AVAILABLE, /* IRQ9 PCI, often acpi */
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PIRQ_PENALTY_PCI_AVAILABLE, /* IRQ10 PCI */
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PIRQ_PENALTY_PCI_AVAILABLE, /* IRQ11 PCI */
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PIRQ_PENALTY_ISA_USED, /* IRQ12 mouse */
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PIRQ_PENALTY_ISA_USED, /* IRQ13 fpe, sometimes */
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PIRQ_PENALTY_ISA_USED, /* IRQ14 ide0 */
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PIRQ_PENALTY_ISA_USED, /* IRQ15 ide1 */
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int __init acpi_irq_penalty_init(void)
481
struct acpi_pci_link *link;
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* Update penalties to facilitate IRQ balancing.
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list_for_each_entry(link, &acpi_link_list, list) {
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* reflect the possible and active irqs in the penalty table --
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* useful for breaking ties.
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if (link->irq.possible_count) {
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PIRQ_PENALTY_PCI_POSSIBLE /
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link->irq.possible_count;
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for (i = 0; i < link->irq.possible_count; i++) {
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if (link->irq.possible[i] < ACPI_MAX_ISA_IRQ)
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acpi_irq_penalty[link->irq.
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} else if (link->irq.active) {
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acpi_irq_penalty[link->irq.active] +=
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PIRQ_PENALTY_PCI_POSSIBLE;
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/* Add a penalty for the SCI */
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acpi_irq_penalty[acpi_gbl_FADT.sci_interrupt] += PIRQ_PENALTY_PCI_USING;
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static int acpi_irq_balance = -1; /* 0: static, 1: balance */
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static int acpi_pci_link_allocate(struct acpi_pci_link *link)
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if (link->irq.initialized) {
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if (link->refcnt == 0)
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/* This means the link is disabled but initialized */
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acpi_pci_link_set(link, link->irq.active);
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* search for active IRQ in list of possible IRQs.
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for (i = 0; i < link->irq.possible_count; ++i) {
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if (link->irq.active == link->irq.possible[i])
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* forget active IRQ that is not in possible list
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if (i == link->irq.possible_count) {
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printk(KERN_WARNING PREFIX "_CRS %d not found"
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" in _PRS\n", link->irq.active);
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link->irq.active = 0;
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* if active found, use it; else pick entry from end of possible list.
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if (link->irq.active)
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irq = link->irq.active;
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irq = link->irq.possible[link->irq.possible_count - 1];
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if (acpi_irq_balance || !link->irq.active) {
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* Select the best IRQ. This is done in reverse to promote
557
* the use of IRQs 9, 10, 11, and >15.
559
for (i = (link->irq.possible_count - 1); i >= 0; i--) {
560
if (acpi_irq_penalty[irq] >
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acpi_irq_penalty[link->irq.possible[i]])
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irq = link->irq.possible[i];
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/* Attempt to enable the link device at this IRQ. */
567
if (acpi_pci_link_set(link, irq)) {
568
printk(KERN_ERR PREFIX "Unable to set IRQ for %s [%s]. "
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"Try pci=noacpi or acpi=off\n",
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acpi_device_name(link->device),
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acpi_device_bid(link->device));
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acpi_irq_penalty[link->irq.active] += PIRQ_PENALTY_PCI_USING;
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printk(KERN_WARNING PREFIX "%s [%s] enabled at IRQ %d\n",
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acpi_device_name(link->device),
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acpi_device_bid(link->device), link->irq.active);
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link->irq.initialized = 1;
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* acpi_pci_link_allocate_irq
586
* success: return IRQ >= 0
589
int acpi_pci_link_allocate_irq(acpi_handle handle, int index, int *triggering,
590
int *polarity, char **name)
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struct acpi_device *device;
594
struct acpi_pci_link *link;
596
result = acpi_bus_get_device(handle, &device);
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printk(KERN_ERR PREFIX "Invalid link device\n");
602
link = acpi_driver_data(device);
604
printk(KERN_ERR PREFIX "Invalid link context\n");
608
/* TBD: Support multiple index (IRQ) entries per Link Device */
610
printk(KERN_ERR PREFIX "Invalid index %d\n", index);
614
mutex_lock(&acpi_link_lock);
615
if (acpi_pci_link_allocate(link)) {
616
mutex_unlock(&acpi_link_lock);
620
if (!link->irq.active) {
621
mutex_unlock(&acpi_link_lock);
622
printk(KERN_ERR PREFIX "Link active IRQ is 0!\n");
626
mutex_unlock(&acpi_link_lock);
629
*triggering = link->irq.triggering;
631
*polarity = link->irq.polarity;
633
*name = acpi_device_bid(link->device);
634
ACPI_DEBUG_PRINT((ACPI_DB_INFO,
635
"Link %s is referenced\n",
636
acpi_device_bid(link->device)));
637
return (link->irq.active);
641
* We don't change link's irq information here. After it is reenabled, we
642
* continue use the info
644
int acpi_pci_link_free_irq(acpi_handle handle)
646
struct acpi_device *device;
647
struct acpi_pci_link *link;
650
result = acpi_bus_get_device(handle, &device);
652
printk(KERN_ERR PREFIX "Invalid link device\n");
656
link = acpi_driver_data(device);
658
printk(KERN_ERR PREFIX "Invalid link context\n");
662
mutex_lock(&acpi_link_lock);
663
if (!link->irq.initialized) {
664
mutex_unlock(&acpi_link_lock);
665
printk(KERN_ERR PREFIX "Link isn't initialized\n");
670
* The Link reference count allows us to _DISable an unused link
671
* and suspend time, and set it again on resume.
672
* However, 2.6.12 still has irq_router.resume
673
* which blindly restores the link state.
674
* So we disable the reference count method
675
* to prevent duplicate acpi_pci_link_set()
676
* which would harm some systems
680
ACPI_DEBUG_PRINT((ACPI_DB_INFO,
681
"Link %s is dereferenced\n",
682
acpi_device_bid(link->device)));
684
if (link->refcnt == 0)
685
acpi_evaluate_object(link->device->handle, "_DIS", NULL, NULL);
687
mutex_unlock(&acpi_link_lock);
688
return (link->irq.active);
691
/* --------------------------------------------------------------------------
693
-------------------------------------------------------------------------- */
695
static int acpi_pci_link_add(struct acpi_device *device)
698
struct acpi_pci_link *link;
702
link = kzalloc(sizeof(struct acpi_pci_link), GFP_KERNEL);
706
link->device = device;
707
strcpy(acpi_device_name(device), ACPI_PCI_LINK_DEVICE_NAME);
708
strcpy(acpi_device_class(device), ACPI_PCI_LINK_CLASS);
709
device->driver_data = link;
711
mutex_lock(&acpi_link_lock);
712
result = acpi_pci_link_get_possible(link);
716
/* query and set link->irq.active */
717
acpi_pci_link_get_current(link);
719
printk(KERN_INFO PREFIX "%s [%s] (IRQs", acpi_device_name(device),
720
acpi_device_bid(device));
721
for (i = 0; i < link->irq.possible_count; i++) {
722
if (link->irq.active == link->irq.possible[i]) {
723
printk(" *%d", link->irq.possible[i]);
726
printk(" %d", link->irq.possible[i]);
732
printk(" *%d", link->irq.active);
734
if (!link->device->status.enabled)
735
printk(", disabled.");
739
list_add_tail(&link->list, &acpi_link_list);
742
/* disable all links -- to be activated on use */
743
acpi_evaluate_object(device->handle, "_DIS", NULL, NULL);
744
mutex_unlock(&acpi_link_lock);
752
static int acpi_pci_link_resume(struct acpi_pci_link *link)
754
if (link->refcnt && link->irq.active && link->irq.initialized)
755
return (acpi_pci_link_set(link, link->irq.active));
760
static void irqrouter_resume(void)
762
struct acpi_pci_link *link;
764
list_for_each_entry(link, &acpi_link_list, list) {
765
acpi_pci_link_resume(link);
769
static int acpi_pci_link_remove(struct acpi_device *device, int type)
771
struct acpi_pci_link *link;
773
link = acpi_driver_data(device);
775
mutex_lock(&acpi_link_lock);
776
list_del(&link->list);
777
mutex_unlock(&acpi_link_lock);
784
* modify acpi_irq_penalty[] from cmdline
786
static int __init acpi_irq_penalty_update(char *str, int used)
790
for (i = 0; i < 16; i++) {
794
retval = get_option(&str, &irq);
797
break; /* no number found */
802
if (irq >= ARRAY_SIZE(acpi_irq_penalty))
806
acpi_irq_penalty[irq] += PIRQ_PENALTY_ISA_USED;
808
acpi_irq_penalty[irq] = PIRQ_PENALTY_PCI_AVAILABLE;
810
if (retval != 2) /* no next number */
817
* We'd like PNP to call this routine for the
818
* single ISA_USED value for each legacy device.
819
* But instead it calls us with each POSSIBLE setting.
820
* There is no ISA_POSSIBLE weight, so we simply use
821
* the (small) PCI_USING penalty.
823
void acpi_penalize_isa_irq(int irq, int active)
825
if (irq >= 0 && irq < ARRAY_SIZE(acpi_irq_penalty)) {
827
acpi_irq_penalty[irq] += PIRQ_PENALTY_ISA_USED;
829
acpi_irq_penalty[irq] += PIRQ_PENALTY_PCI_USING;
834
* Over-ride default table to reserve additional IRQs for use by ISA
835
* e.g. acpi_irq_isa=5
836
* Useful for telling ACPI how not to interfere with your ISA sound card.
838
static int __init acpi_irq_isa(char *str)
840
return acpi_irq_penalty_update(str, 1);
843
__setup("acpi_irq_isa=", acpi_irq_isa);
846
* Over-ride default table to free additional IRQs for use by PCI
847
* e.g. acpi_irq_pci=7,15
848
* Used for acpi_irq_balance to free up IRQs to reduce PCI IRQ sharing.
850
static int __init acpi_irq_pci(char *str)
852
return acpi_irq_penalty_update(str, 0);
855
__setup("acpi_irq_pci=", acpi_irq_pci);
857
static int __init acpi_irq_nobalance_set(char *str)
859
acpi_irq_balance = 0;
863
__setup("acpi_irq_nobalance", acpi_irq_nobalance_set);
865
static int __init acpi_irq_balance_set(char *str)
867
acpi_irq_balance = 1;
871
__setup("acpi_irq_balance", acpi_irq_balance_set);
873
static struct syscore_ops irqrouter_syscore_ops = {
874
.resume = irqrouter_resume,
877
static int __init irqrouter_init_ops(void)
879
if (!acpi_disabled && !acpi_noirq)
880
register_syscore_ops(&irqrouter_syscore_ops);
885
device_initcall(irqrouter_init_ops);
887
static int __init acpi_pci_link_init(void)
892
if (acpi_irq_balance == -1) {
893
/* no command line switch: enable balancing in IOAPIC mode */
894
if (acpi_irq_model == ACPI_IRQ_MODEL_IOAPIC)
895
acpi_irq_balance = 1;
897
acpi_irq_balance = 0;
900
if (acpi_bus_register_driver(&acpi_pci_link_driver) < 0)
906
subsys_initcall(acpi_pci_link_init);