Adding upstream version 4.19.249.upstream/4.19.249upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 946 insertions, 0 deletions

diff --git a/drivers/acpi/pci_link.c b/drivers/acpi/pci_link.c
new file mode 100644
index 000000000..d5eec352a
--- /dev/null
+++ b/drivers/acpi/pci_link.c
@@ -0,0 +1,946 @@
+/*
+ *  pci_link.c - ACPI PCI Interrupt Link Device Driver ($Revision: 34 $)
+ *
+ *  Copyright (C) 2001, 2002 Andy Grover <andrew.grover@intel.com>
+ *  Copyright (C) 2001, 2002 Paul Diefenbaugh <paul.s.diefenbaugh@intel.com>
+ *  Copyright (C) 2002       Dominik Brodowski <devel@brodo.de>
+ *
+ * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation; either version 2 of the License, or (at
+ *  your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful, but
+ *  WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ *  General Public License for more details.
+ *
+ * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ *
+ * TBD: 
+ *      1. Support more than one IRQ resource entry per link device (index).
+ *	2. Implement start/stop mechanism and use ACPI Bus Driver facilities
+ *	   for IRQ management (e.g. start()->_SRS).
+ */
+
+#include <linux/syscore_ops.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/types.h>
+#include <linux/spinlock.h>
+#include <linux/pm.h>
+#include <linux/pci.h>
+#include <linux/mutex.h>
+#include <linux/slab.h>
+#include <linux/acpi.h>
+#include <linux/irq.h>
+
+#include "internal.h"
+
+#define _COMPONENT			ACPI_PCI_COMPONENT
+ACPI_MODULE_NAME("pci_link");
+#define ACPI_PCI_LINK_CLASS		"pci_irq_routing"
+#define ACPI_PCI_LINK_DEVICE_NAME	"PCI Interrupt Link"
+#define ACPI_PCI_LINK_FILE_INFO		"info"
+#define ACPI_PCI_LINK_FILE_STATUS	"state"
+#define ACPI_PCI_LINK_MAX_POSSIBLE	16
+
+static int acpi_pci_link_add(struct acpi_device *device,
+			     const struct acpi_device_id *not_used);
+static void acpi_pci_link_remove(struct acpi_device *device);
+
+static const struct acpi_device_id link_device_ids[] = {
+	{"PNP0C0F", 0},
+	{"", 0},
+};
+
+static struct acpi_scan_handler pci_link_handler = {
+	.ids = link_device_ids,
+	.attach = acpi_pci_link_add,
+	.detach = acpi_pci_link_remove,
+};
+
+/*
+ * If a link is initialized, we never change its active and initialized
+ * later even the link is disable. Instead, we just repick the active irq
+ */
+struct acpi_pci_link_irq {
+	u32 active;		/* Current IRQ */
+	u8 triggering;		/* All IRQs */
+	u8 polarity;		/* All IRQs */
+	u8 resource_type;
+	u8 possible_count;
+	u32 possible[ACPI_PCI_LINK_MAX_POSSIBLE];
+	u8 initialized:1;
+	u8 reserved:7;
+};
+
+struct acpi_pci_link {
+	struct list_head		list;
+	struct acpi_device		*device;
+	struct acpi_pci_link_irq	irq;
+	int				refcnt;
+};
+
+static LIST_HEAD(acpi_link_list);
+static DEFINE_MUTEX(acpi_link_lock);
+static int sci_irq = -1, sci_penalty;
+
+/* --------------------------------------------------------------------------
+                            PCI Link Device Management
+   -------------------------------------------------------------------------- */
+
+/*
+ * set context (link) possible list from resource list
+ */
+static acpi_status acpi_pci_link_check_possible(struct acpi_resource *resource,
+						void *context)
+{
+	struct acpi_pci_link *link = context;
+	u32 i;
+
+	switch (resource->type) {
+	case ACPI_RESOURCE_TYPE_START_DEPENDENT:
+	case ACPI_RESOURCE_TYPE_END_TAG:
+		return AE_OK;
+	case ACPI_RESOURCE_TYPE_IRQ:
+		{
+			struct acpi_resource_irq *p = &resource->data.irq;
+			if (!p || !p->interrupt_count) {
+				ACPI_DEBUG_PRINT((ACPI_DB_INFO,
+						  "Blank _PRS IRQ resource\n"));
+				return AE_OK;
+			}
+			for (i = 0;
+			     (i < p->interrupt_count
+			      && i < ACPI_PCI_LINK_MAX_POSSIBLE); i++) {
+				if (!p->interrupts[i]) {
+					printk(KERN_WARNING PREFIX
+					       "Invalid _PRS IRQ %d\n",
+					       p->interrupts[i]);
+					continue;
+				}
+				link->irq.possible[i] = p->interrupts[i];
+				link->irq.possible_count++;
+			}
+			link->irq.triggering = p->triggering;
+			link->irq.polarity = p->polarity;
+			link->irq.resource_type = ACPI_RESOURCE_TYPE_IRQ;
+			break;
+		}
+	case ACPI_RESOURCE_TYPE_EXTENDED_IRQ:
+		{
+			struct acpi_resource_extended_irq *p =
+			    &resource->data.extended_irq;
+			if (!p || !p->interrupt_count) {
+				printk(KERN_WARNING PREFIX
+					      "Blank _PRS EXT IRQ resource\n");
+				return AE_OK;
+			}
+			for (i = 0;
+			     (i < p->interrupt_count
+			      && i < ACPI_PCI_LINK_MAX_POSSIBLE); i++) {
+				if (!p->interrupts[i]) {
+					printk(KERN_WARNING PREFIX
+					       "Invalid _PRS IRQ %d\n",
+					       p->interrupts[i]);
+					continue;
+				}
+				link->irq.possible[i] = p->interrupts[i];
+				link->irq.possible_count++;
+			}
+			link->irq.triggering = p->triggering;
+			link->irq.polarity = p->polarity;
+			link->irq.resource_type = ACPI_RESOURCE_TYPE_EXTENDED_IRQ;
+			break;
+		}
+	default:
+		printk(KERN_ERR PREFIX "_PRS resource type 0x%x isn't an IRQ\n",
+		       resource->type);
+		return AE_OK;
+	}
+
+	return AE_CTRL_TERMINATE;
+}
+
+static int acpi_pci_link_get_possible(struct acpi_pci_link *link)
+{
+	acpi_status status;
+
+	status = acpi_walk_resources(link->device->handle, METHOD_NAME__PRS,
+				     acpi_pci_link_check_possible, link);
+	if (ACPI_FAILURE(status)) {
+		acpi_handle_debug(link->device->handle, "_PRS not present or invalid");
+		return 0;
+	}
+
+	ACPI_DEBUG_PRINT((ACPI_DB_INFO,
+			  "Found %d possible IRQs\n",
+			  link->irq.possible_count));
+
+	return 0;
+}
+
+static acpi_status acpi_pci_link_check_current(struct acpi_resource *resource,
+					       void *context)
+{
+	int *irq = context;
+
+	switch (resource->type) {
+	case ACPI_RESOURCE_TYPE_START_DEPENDENT:
+	case ACPI_RESOURCE_TYPE_END_TAG:
+		return AE_OK;
+	case ACPI_RESOURCE_TYPE_IRQ:
+		{
+			struct acpi_resource_irq *p = &resource->data.irq;
+			if (!p || !p->interrupt_count) {
+				/*
+				 * IRQ descriptors may have no IRQ# bits set,
+				 * particularly those those w/ _STA disabled
+				 */
+				ACPI_DEBUG_PRINT((ACPI_DB_INFO,
+						  "Blank _CRS IRQ resource\n"));
+				return AE_OK;
+			}
+			*irq = p->interrupts[0];
+			break;
+		}
+	case ACPI_RESOURCE_TYPE_EXTENDED_IRQ:
+		{
+			struct acpi_resource_extended_irq *p =
+			    &resource->data.extended_irq;
+			if (!p || !p->interrupt_count) {
+				/*
+				 * extended IRQ descriptors must
+				 * return at least 1 IRQ
+				 */
+				printk(KERN_WARNING PREFIX
+					      "Blank _CRS EXT IRQ resource\n");
+				return AE_OK;
+			}
+			*irq = p->interrupts[0];
+			break;
+		}
+		break;
+	default:
+		printk(KERN_ERR PREFIX "_CRS resource type 0x%x isn't an IRQ\n",
+		       resource->type);
+		return AE_OK;
+	}
+
+	return AE_CTRL_TERMINATE;
+}
+
+/*
+ * Run _CRS and set link->irq.active
+ *
+ * return value:
+ * 0 - success
+ * !0 - failure
+ */
+static int acpi_pci_link_get_current(struct acpi_pci_link *link)
+{
+	int result = 0;
+	acpi_status status;
+	int irq = 0;
+
+	link->irq.active = 0;
+
+	/* in practice, status disabled is meaningless, ignore it */
+	if (acpi_strict) {
+		/* Query _STA, set link->device->status */
+		result = acpi_bus_get_status(link->device);
+		if (result) {
+			printk(KERN_ERR PREFIX "Unable to read status\n");
+			goto end;
+		}
+
+		if (!link->device->status.enabled) {
+			ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Link disabled\n"));
+			return 0;
+		}
+	}
+
+	/* 
+	 * Query and parse _CRS to get the current IRQ assignment. 
+	 */
+
+	status = acpi_walk_resources(link->device->handle, METHOD_NAME__CRS,
+				     acpi_pci_link_check_current, &irq);
+	if (ACPI_FAILURE(status)) {
+		ACPI_EXCEPTION((AE_INFO, status, "Evaluating _CRS"));
+		result = -ENODEV;
+		goto end;
+	}
+
+	if (acpi_strict && !irq) {
+		printk(KERN_ERR PREFIX "_CRS returned 0\n");
+		result = -ENODEV;
+	}
+
+	link->irq.active = irq;
+
+	ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Link at IRQ %d \n", link->irq.active));
+
+      end:
+	return result;
+}
+
+static int acpi_pci_link_set(struct acpi_pci_link *link, int irq)
+{
+	int result;
+	acpi_status status;
+	struct {
+		struct acpi_resource res;
+		struct acpi_resource end;
+	} *resource;
+	struct acpi_buffer buffer = { 0, NULL };
+
+	if (!irq)
+		return -EINVAL;
+
+	resource = kzalloc(sizeof(*resource) + 1, irqs_disabled() ? GFP_ATOMIC: GFP_KERNEL);
+	if (!resource)
+		return -ENOMEM;
+
+	buffer.length = sizeof(*resource) + 1;
+	buffer.pointer = resource;
+
+	switch (link->irq.resource_type) {
+	case ACPI_RESOURCE_TYPE_IRQ:
+		resource->res.type = ACPI_RESOURCE_TYPE_IRQ;
+		resource->res.length = sizeof(struct acpi_resource);
+		resource->res.data.irq.triggering = link->irq.triggering;
+		resource->res.data.irq.polarity =
+		    link->irq.polarity;
+		if (link->irq.triggering == ACPI_EDGE_SENSITIVE)
+			resource->res.data.irq.sharable =
+			    ACPI_EXCLUSIVE;
+		else
+			resource->res.data.irq.sharable = ACPI_SHARED;
+		resource->res.data.irq.interrupt_count = 1;
+		resource->res.data.irq.interrupts[0] = irq;
+		break;
+
+	case ACPI_RESOURCE_TYPE_EXTENDED_IRQ:
+		resource->res.type = ACPI_RESOURCE_TYPE_EXTENDED_IRQ;
+		resource->res.length = sizeof(struct acpi_resource);
+		resource->res.data.extended_irq.producer_consumer =
+		    ACPI_CONSUMER;
+		resource->res.data.extended_irq.triggering =
+		    link->irq.triggering;
+		resource->res.data.extended_irq.polarity =
+		    link->irq.polarity;
+		if (link->irq.triggering == ACPI_EDGE_SENSITIVE)
+			resource->res.data.irq.sharable =
+			    ACPI_EXCLUSIVE;
+		else
+			resource->res.data.irq.sharable = ACPI_SHARED;
+		resource->res.data.extended_irq.interrupt_count = 1;
+		resource->res.data.extended_irq.interrupts[0] = irq;
+		/* ignore resource_source, it's optional */
+		break;
+	default:
+		printk(KERN_ERR PREFIX "Invalid Resource_type %d\n", link->irq.resource_type);
+		result = -EINVAL;
+		goto end;
+
+	}
+	resource->end.type = ACPI_RESOURCE_TYPE_END_TAG;
+	resource->end.length = sizeof(struct acpi_resource);
+
+	/* Attempt to set the resource */
+	status = acpi_set_current_resources(link->device->handle, &buffer);
+
+	/* check for total failure */
+	if (ACPI_FAILURE(status)) {
+		ACPI_EXCEPTION((AE_INFO, status, "Evaluating _SRS"));
+		result = -ENODEV;
+		goto end;
+	}
+
+	/* Query _STA, set device->status */
+	result = acpi_bus_get_status(link->device);
+	if (result) {
+		printk(KERN_ERR PREFIX "Unable to read status\n");
+		goto end;
+	}
+	if (!link->device->status.enabled) {
+		printk(KERN_WARNING PREFIX
+			      "%s [%s] disabled and referenced, BIOS bug\n",
+			      acpi_device_name(link->device),
+			      acpi_device_bid(link->device));
+	}
+
+	/* Query _CRS, set link->irq.active */
+	result = acpi_pci_link_get_current(link);
+	if (result) {
+		goto end;
+	}
+
+	/*
+	 * Is current setting not what we set?
+	 * set link->irq.active
+	 */
+	if (link->irq.active != irq) {
+		/*
+		 * policy: when _CRS doesn't return what we just _SRS
+		 * assume _SRS worked and override _CRS value.
+		 */
+		printk(KERN_WARNING PREFIX
+			      "%s [%s] BIOS reported IRQ %d, using IRQ %d\n",
+			      acpi_device_name(link->device),
+			      acpi_device_bid(link->device), link->irq.active, irq);
+		link->irq.active = irq;
+	}
+
+	ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Set IRQ %d\n", link->irq.active));
+
+      end:
+	kfree(resource);
+	return result;
+}
+
+/* --------------------------------------------------------------------------
+                            PCI Link IRQ Management
+   -------------------------------------------------------------------------- */
+
+/*
+ * "acpi_irq_balance" (default in APIC mode) enables ACPI to use PIC Interrupt
+ * Link Devices to move the PIRQs around to minimize sharing.
+ * 
+ * "acpi_irq_nobalance" (default in PIC mode) tells ACPI not to move any PIC IRQs
+ * that the BIOS has already set to active.  This is necessary because
+ * ACPI has no automatic means of knowing what ISA IRQs are used.  Note that
+ * if the BIOS doesn't set a Link Device active, ACPI needs to program it
+ * even if acpi_irq_nobalance is set.
+ *
+ * A tables of penalties avoids directing PCI interrupts to well known
+ * ISA IRQs. Boot params are available to over-ride the default table:
+ *
+ * List interrupts that are free for PCI use.
+ * acpi_irq_pci=n[,m]
+ *
+ * List interrupts that should not be used for PCI:
+ * acpi_irq_isa=n[,m]
+ *
+ * Note that PCI IRQ routers have a list of possible IRQs,
+ * which may not include the IRQs this table says are available.
+ * 
+ * Since this heuristic can't tell the difference between a link
+ * that no device will attach to, vs. a link which may be shared
+ * by multiple active devices -- it is not optimal.
+ *
+ * If interrupt performance is that important, get an IO-APIC system
+ * with a pin dedicated to each device.  Or for that matter, an MSI
+ * enabled system.
+ */
+
+#define ACPI_MAX_ISA_IRQS	16
+
+#define PIRQ_PENALTY_PCI_POSSIBLE	(16*16)
+#define PIRQ_PENALTY_PCI_USING		(16*16*16)
+#define PIRQ_PENALTY_ISA_TYPICAL	(16*16*16*16)
+#define PIRQ_PENALTY_ISA_USED		(16*16*16*16*16)
+#define PIRQ_PENALTY_ISA_ALWAYS		(16*16*16*16*16*16)
+
+static int acpi_isa_irq_penalty[ACPI_MAX_ISA_IRQS] = {
+	PIRQ_PENALTY_ISA_ALWAYS,	/* IRQ0 timer */
+	PIRQ_PENALTY_ISA_ALWAYS,	/* IRQ1 keyboard */
+	PIRQ_PENALTY_ISA_ALWAYS,	/* IRQ2 cascade */
+	PIRQ_PENALTY_ISA_TYPICAL,	/* IRQ3 serial */
+	PIRQ_PENALTY_ISA_TYPICAL,	/* IRQ4 serial */
+	PIRQ_PENALTY_ISA_TYPICAL,	/* IRQ5 sometimes SoundBlaster */
+	PIRQ_PENALTY_ISA_TYPICAL,	/* IRQ6 */
+	PIRQ_PENALTY_ISA_TYPICAL,	/* IRQ7 parallel, spurious */
+	PIRQ_PENALTY_ISA_TYPICAL,	/* IRQ8 rtc, sometimes */
+	0,				/* IRQ9  PCI, often acpi */
+	0,				/* IRQ10 PCI */
+	0,				/* IRQ11 PCI */
+	PIRQ_PENALTY_ISA_USED,		/* IRQ12 mouse */
+	PIRQ_PENALTY_ISA_USED,		/* IRQ13 fpe, sometimes */
+	PIRQ_PENALTY_ISA_USED,		/* IRQ14 ide0 */
+	PIRQ_PENALTY_ISA_USED,		/* IRQ15 ide1 */
+	/* >IRQ15 */
+};
+
+static int acpi_irq_pci_sharing_penalty(int irq)
+{
+	struct acpi_pci_link *link;
+	int penalty = 0;
+	int i;
+
+	list_for_each_entry(link, &acpi_link_list, list) {
+		/*
+		 * If a link is active, penalize its IRQ heavily
+		 * so we try to choose a different IRQ.
+		 */
+		if (link->irq.active && link->irq.active == irq)
+			penalty += PIRQ_PENALTY_PCI_USING;
+
+		/*
+		 * penalize the IRQs PCI might use, but not as severely.
+		 */
+		for (i = 0; i < link->irq.possible_count; i++)
+			if (link->irq.possible[i] == irq)
+				penalty += PIRQ_PENALTY_PCI_POSSIBLE /
+					link->irq.possible_count;
+	}
+
+	return penalty;
+}
+
+static int acpi_irq_get_penalty(int irq)
+{
+	int penalty = 0;
+
+	if (irq == sci_irq)
+		penalty += sci_penalty;
+
+	if (irq < ACPI_MAX_ISA_IRQS)
+		return penalty + acpi_isa_irq_penalty[irq];
+
+	return penalty + acpi_irq_pci_sharing_penalty(irq);
+}
+
+int __init acpi_irq_penalty_init(void)
+{
+	struct acpi_pci_link *link;
+	int i;
+
+	/*
+	 * Update penalties to facilitate IRQ balancing.
+	 */
+	list_for_each_entry(link, &acpi_link_list, list) {
+
+		/*
+		 * reflect the possible and active irqs in the penalty table --
+		 * useful for breaking ties.
+		 */
+		if (link->irq.possible_count) {
+			int penalty =
+			    PIRQ_PENALTY_PCI_POSSIBLE /
+			    link->irq.possible_count;
+
+			for (i = 0; i < link->irq.possible_count; i++) {
+				if (link->irq.possible[i] < ACPI_MAX_ISA_IRQS)
+					acpi_isa_irq_penalty[link->irq.
+							 possible[i]] +=
+					    penalty;
+			}
+
+		} else if (link->irq.active &&
+				(link->irq.active < ACPI_MAX_ISA_IRQS)) {
+			acpi_isa_irq_penalty[link->irq.active] +=
+			    PIRQ_PENALTY_PCI_POSSIBLE;
+		}
+	}
+
+	return 0;
+}
+
+static int acpi_irq_balance = -1;	/* 0: static, 1: balance */
+
+static int acpi_pci_link_allocate(struct acpi_pci_link *link)
+{
+	int irq;
+	int i;
+
+	if (link->irq.initialized) {
+		if (link->refcnt == 0)
+			/* This means the link is disabled but initialized */
+			acpi_pci_link_set(link, link->irq.active);
+		return 0;
+	}
+
+	/*
+	 * search for active IRQ in list of possible IRQs.
+	 */
+	for (i = 0; i < link->irq.possible_count; ++i) {
+		if (link->irq.active == link->irq.possible[i])
+			break;
+	}
+	/*
+	 * forget active IRQ that is not in possible list
+	 */
+	if (i == link->irq.possible_count) {
+		if (acpi_strict)
+			printk(KERN_WARNING PREFIX "_CRS %d not found"
+				      " in _PRS\n", link->irq.active);
+		link->irq.active = 0;
+	}
+
+	/*
+	 * if active found, use it; else pick entry from end of possible list.
+	 */
+	if (link->irq.active)
+		irq = link->irq.active;
+	else
+		irq = link->irq.possible[link->irq.possible_count - 1];
+
+	if (acpi_irq_balance || !link->irq.active) {
+		/*
+		 * Select the best IRQ.  This is done in reverse to promote
+		 * the use of IRQs 9, 10, 11, and >15.
+		 */
+		for (i = (link->irq.possible_count - 1); i >= 0; i--) {
+			if (acpi_irq_get_penalty(irq) >
+			    acpi_irq_get_penalty(link->irq.possible[i]))
+				irq = link->irq.possible[i];
+		}
+	}
+	if (acpi_irq_get_penalty(irq) >= PIRQ_PENALTY_ISA_ALWAYS) {
+		printk(KERN_ERR PREFIX "No IRQ available for %s [%s]. "
+			    "Try pci=noacpi or acpi=off\n",
+			    acpi_device_name(link->device),
+			    acpi_device_bid(link->device));
+		return -ENODEV;
+	}
+
+	/* Attempt to enable the link device at this IRQ. */
+	if (acpi_pci_link_set(link, irq)) {
+		printk(KERN_ERR PREFIX "Unable to set IRQ for %s [%s]. "
+			    "Try pci=noacpi or acpi=off\n",
+			    acpi_device_name(link->device),
+			    acpi_device_bid(link->device));
+		return -ENODEV;
+	} else {
+		if (link->irq.active < ACPI_MAX_ISA_IRQS)
+			acpi_isa_irq_penalty[link->irq.active] +=
+				PIRQ_PENALTY_PCI_USING;
+
+		pr_info("%s [%s] enabled at IRQ %d\n",
+		       acpi_device_name(link->device),
+		       acpi_device_bid(link->device), link->irq.active);
+	}
+
+	link->irq.initialized = 1;
+	return 0;
+}
+
+/*
+ * acpi_pci_link_allocate_irq
+ * success: return IRQ >= 0
+ * failure: return -1
+ */
+int acpi_pci_link_allocate_irq(acpi_handle handle, int index, int *triggering,
+			       int *polarity, char **name)
+{
+	int result;
+	struct acpi_device *device;
+	struct acpi_pci_link *link;
+
+	result = acpi_bus_get_device(handle, &device);
+	if (result) {
+		printk(KERN_ERR PREFIX "Invalid link device\n");
+		return -1;
+	}
+
+	link = acpi_driver_data(device);
+	if (!link) {
+		printk(KERN_ERR PREFIX "Invalid link context\n");
+		return -1;
+	}
+
+	/* TBD: Support multiple index (IRQ) entries per Link Device */
+	if (index) {
+		printk(KERN_ERR PREFIX "Invalid index %d\n", index);
+		return -1;
+	}
+
+	mutex_lock(&acpi_link_lock);
+	if (acpi_pci_link_allocate(link)) {
+		mutex_unlock(&acpi_link_lock);
+		return -1;
+	}
+
+	if (!link->irq.active) {
+		mutex_unlock(&acpi_link_lock);
+		printk(KERN_ERR PREFIX "Link active IRQ is 0!\n");
+		return -1;
+	}
+	link->refcnt++;
+	mutex_unlock(&acpi_link_lock);
+
+	if (triggering)
+		*triggering = link->irq.triggering;
+	if (polarity)
+		*polarity = link->irq.polarity;
+	if (name)
+		*name = acpi_device_bid(link->device);
+	ACPI_DEBUG_PRINT((ACPI_DB_INFO,
+			  "Link %s is referenced\n",
+			  acpi_device_bid(link->device)));
+	return (link->irq.active);
+}
+
+/*
+ * We don't change link's irq information here.  After it is reenabled, we
+ * continue use the info
+ */
+int acpi_pci_link_free_irq(acpi_handle handle)
+{
+	struct acpi_device *device;
+	struct acpi_pci_link *link;
+	acpi_status result;
+
+	result = acpi_bus_get_device(handle, &device);
+	if (result) {
+		printk(KERN_ERR PREFIX "Invalid link device\n");
+		return -1;
+	}
+
+	link = acpi_driver_data(device);
+	if (!link) {
+		printk(KERN_ERR PREFIX "Invalid link context\n");
+		return -1;
+	}
+
+	mutex_lock(&acpi_link_lock);
+	if (!link->irq.initialized) {
+		mutex_unlock(&acpi_link_lock);
+		printk(KERN_ERR PREFIX "Link isn't initialized\n");
+		return -1;
+	}
+#ifdef	FUTURE_USE
+	/*
+	 * The Link reference count allows us to _DISable an unused link
+	 * and suspend time, and set it again  on resume.
+	 * However, 2.6.12 still has irq_router.resume
+	 * which blindly restores the link state.
+	 * So we disable the reference count method
+	 * to prevent duplicate acpi_pci_link_set()
+	 * which would harm some systems
+	 */
+	link->refcnt--;
+#endif
+	ACPI_DEBUG_PRINT((ACPI_DB_INFO,
+			  "Link %s is dereferenced\n",
+			  acpi_device_bid(link->device)));
+
+	if (link->refcnt == 0)
+		acpi_evaluate_object(link->device->handle, "_DIS", NULL, NULL);
+
+	mutex_unlock(&acpi_link_lock);
+	return (link->irq.active);
+}
+
+/* --------------------------------------------------------------------------
+                                 Driver Interface
+   -------------------------------------------------------------------------- */
+
+static int acpi_pci_link_add(struct acpi_device *device,
+			     const struct acpi_device_id *not_used)
+{
+	int result;
+	struct acpi_pci_link *link;
+	int i;
+	int found = 0;
+
+	link = kzalloc(sizeof(struct acpi_pci_link), GFP_KERNEL);
+	if (!link)
+		return -ENOMEM;
+
+	link->device = device;
+	strcpy(acpi_device_name(device), ACPI_PCI_LINK_DEVICE_NAME);
+	strcpy(acpi_device_class(device), ACPI_PCI_LINK_CLASS);
+	device->driver_data = link;
+
+	mutex_lock(&acpi_link_lock);
+	result = acpi_pci_link_get_possible(link);
+	if (result)
+		goto end;
+
+	/* query and set link->irq.active */
+	acpi_pci_link_get_current(link);
+
+	printk(KERN_INFO PREFIX "%s [%s] (IRQs", acpi_device_name(device),
+	       acpi_device_bid(device));
+	for (i = 0; i < link->irq.possible_count; i++) {
+		if (link->irq.active == link->irq.possible[i]) {
+			printk(KERN_CONT " *%d", link->irq.possible[i]);
+			found = 1;
+		} else
+			printk(KERN_CONT " %d", link->irq.possible[i]);
+	}
+
+	printk(KERN_CONT ")");
+
+	if (!found)
+		printk(KERN_CONT " *%d", link->irq.active);
+
+	if (!link->device->status.enabled)
+		printk(KERN_CONT ", disabled.");
+
+	printk(KERN_CONT "\n");
+
+	list_add_tail(&link->list, &acpi_link_list);
+
+      end:
+	/* disable all links -- to be activated on use */
+	acpi_evaluate_object(device->handle, "_DIS", NULL, NULL);
+	mutex_unlock(&acpi_link_lock);
+
+	if (result)
+		kfree(link);
+
+	return result < 0 ? result : 1;
+}
+
+static int acpi_pci_link_resume(struct acpi_pci_link *link)
+{
+	if (link->refcnt && link->irq.active && link->irq.initialized)
+		return (acpi_pci_link_set(link, link->irq.active));
+
+	return 0;
+}
+
+static void irqrouter_resume(void)
+{
+	struct acpi_pci_link *link;
+
+	list_for_each_entry(link, &acpi_link_list, list) {
+		acpi_pci_link_resume(link);
+	}
+}
+
+static void acpi_pci_link_remove(struct acpi_device *device)
+{
+	struct acpi_pci_link *link;
+
+	link = acpi_driver_data(device);
+
+	mutex_lock(&acpi_link_lock);
+	list_del(&link->list);
+	mutex_unlock(&acpi_link_lock);
+
+	kfree(link);
+}
+
+/*
+ * modify acpi_isa_irq_penalty[] from cmdline
+ */
+static int __init acpi_irq_penalty_update(char *str, int used)
+{
+	int i;
+
+	for (i = 0; i < 16; i++) {
+		int retval;
+		int irq;
+		int new_penalty;
+
+		retval = get_option(&str, &irq);
+
+		if (!retval)
+			break;	/* no number found */
+
+		/* see if this is a ISA IRQ */
+		if ((irq < 0) || (irq >= ACPI_MAX_ISA_IRQS))
+			continue;
+
+		if (used)
+			new_penalty = acpi_isa_irq_penalty[irq] +
+					PIRQ_PENALTY_ISA_USED;
+		else
+			new_penalty = 0;
+
+		acpi_isa_irq_penalty[irq] = new_penalty;
+		if (retval != 2)	/* no next number */
+			break;
+	}
+	return 1;
+}
+
+/*
+ * We'd like PNP to call this routine for the
+ * single ISA_USED value for each legacy device.
+ * But instead it calls us with each POSSIBLE setting.
+ * There is no ISA_POSSIBLE weight, so we simply use
+ * the (small) PCI_USING penalty.
+ */
+void acpi_penalize_isa_irq(int irq, int active)
+{
+	if ((irq >= 0) && (irq < ARRAY_SIZE(acpi_isa_irq_penalty)))
+		acpi_isa_irq_penalty[irq] +=
+		  (active ? PIRQ_PENALTY_ISA_USED : PIRQ_PENALTY_PCI_USING);
+}
+
+bool acpi_isa_irq_available(int irq)
+{
+	return irq >= 0 && (irq >= ARRAY_SIZE(acpi_isa_irq_penalty) ||
+		    acpi_irq_get_penalty(irq) < PIRQ_PENALTY_ISA_ALWAYS);
+}
+
+void acpi_penalize_sci_irq(int irq, int trigger, int polarity)
+{
+	sci_irq = irq;
+
+	if (trigger == ACPI_MADT_TRIGGER_LEVEL &&
+	    polarity == ACPI_MADT_POLARITY_ACTIVE_LOW)
+		sci_penalty = PIRQ_PENALTY_PCI_USING;
+	else
+		sci_penalty = PIRQ_PENALTY_ISA_ALWAYS;
+}
+
+/*
+ * Over-ride default table to reserve additional IRQs for use by ISA
+ * e.g. acpi_irq_isa=5
+ * Useful for telling ACPI how not to interfere with your ISA sound card.
+ */
+static int __init acpi_irq_isa(char *str)
+{
+	return acpi_irq_penalty_update(str, 1);
+}
+
+__setup("acpi_irq_isa=", acpi_irq_isa);
+
+/*
+ * Over-ride default table to free additional IRQs for use by PCI
+ * e.g. acpi_irq_pci=7,15
+ * Used for acpi_irq_balance to free up IRQs to reduce PCI IRQ sharing.
+ */
+static int __init acpi_irq_pci(char *str)
+{
+	return acpi_irq_penalty_update(str, 0);
+}
+
+__setup("acpi_irq_pci=", acpi_irq_pci);
+
+static int __init acpi_irq_nobalance_set(char *str)
+{
+	acpi_irq_balance = 0;
+	return 1;
+}
+
+__setup("acpi_irq_nobalance", acpi_irq_nobalance_set);
+
+static int __init acpi_irq_balance_set(char *str)
+{
+	acpi_irq_balance = 1;
+	return 1;
+}
+
+__setup("acpi_irq_balance", acpi_irq_balance_set);
+
+static struct syscore_ops irqrouter_syscore_ops = {
+	.resume = irqrouter_resume,
+};
+
+void __init acpi_pci_link_init(void)
+{
+	if (acpi_noirq)
+		return;
+
+	if (acpi_irq_balance == -1) {
+		/* no command line switch: enable balancing in IOAPIC mode */
+		if (acpi_irq_model == ACPI_IRQ_MODEL_IOAPIC)
+			acpi_irq_balance = 1;
+		else
+			acpi_irq_balance = 0;
+	}
+	register_syscore_ops(&irqrouter_syscore_ops);
+	acpi_scan_add_handler(&pci_link_handler);
+}