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/*

 *  pci_irq.c - ACPI PCI Interrupt Routing ($Revision: 11 $)

 *

 *  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.

 *

 *  You should have received a copy of the GNU General Public License along

 *  with this program; if not, write to the Free Software Foundation, Inc.,

 *  59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.

 *

 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

 */

#include <linux/kernel.h>

#include <linux/module.h>

#include <linux/init.h>

#include <linux/types.h>

#include <linux/proc_fs.h>

#include <linux/spinlock.h>

#include <linux/pm.h>

#include <linux/pci.h>

#include <linux/acpi.h>

#include <acpi/acpi_bus.h>

#include <acpi/acpi_drivers.h>

#define _COMPONENT              ACPI_PCI_COMPONENT

ACPI_MODULE_NAME("pci_irq");

static struct acpi_prt_list acpi_prt;

static DEFINE_SPINLOCK(acpi_prt_lock);

/* --------------------------------------------------------------------------

                         PCI IRQ Routing Table (PRT) Support

   -------------------------------------------------------------------------- */

static struct acpi_prt_entry *acpi_pci_irq_find_prt_entry(int segment,

                                                          int bus,

                                                          int device, int pin)

{

        struct list_head *node = NULL;

        struct acpi_prt_entry *entry = NULL;

        if (!acpi_prt.count)

                return NULL;

        /*

         * Parse through all PRT entries looking for a match on the specified

         * PCI device's segment, bus, device, and pin (don't care about func).

         *

         */

        spin_lock(&acpi_prt_lock);

        list_for_each(node, &acpi_prt.entries) {

                entry = list_entry(node, struct acpi_prt_entry, node);

                if ((segment == entry->id.segment)

                    && (bus == entry->id.bus)

                    && (device == entry->id.device)

                    && (pin == entry->pin)) {

                        spin_unlock(&acpi_prt_lock);

                        return entry;

                }

        }

        spin_unlock(&acpi_prt_lock);

        return NULL;

}

static int

acpi_pci_irq_add_entry(acpi_handle handle,

                       int segment, int bus, struct acpi_pci_routing_table *prt)

{

        struct acpi_prt_entry *entry = NULL;

        if (!prt)

                return -EINVAL;

        entry = kzalloc(sizeof(struct acpi_prt_entry), GFP_KERNEL);

        if (!entry)

                return -ENOMEM;

        entry->id.segment = segment;

        entry->id.bus = bus;

        entry->id.device = (prt->address >> 16) & 0xFFFF;

        entry->id.function = prt->address & 0xFFFF;

        entry->pin = prt->pin;

        /*

         * Type 1: Dynamic

         * ---------------

         * The 'source' field specifies the PCI interrupt link device used to

         * configure the IRQ assigned to this slot|dev|pin.  The 'source_index'

         * indicates which resource descriptor in the resource template (of

         * the link device) this interrupt is allocated from.

         *

         * NOTE: Don't query the Link Device for IRQ information at this time

         *       because Link Device enumeration may not have occurred yet

         *       (e.g. exists somewhere 'below' this _PRT entry in the ACPI

         *       namespace).

         */

        if (prt->source[0]) {

                acpi_get_handle(handle, prt->source, &entry->link.handle);

                entry->link.index = prt->source_index;

        }

        /*

         * Type 2: Static

         * --------------

         * The 'source' field is NULL, and the 'source_index' field specifies

         * the IRQ value, which is hardwired to specific interrupt inputs on

         * the interrupt controller.

         */

        else

                entry->link.index = prt->source_index;

        ACPI_DEBUG_PRINT_RAW((ACPI_DB_INFO,

                              "      %02X:%02X:%02X[%c] -> %s[%d]\n",

                              entry->id.segment, entry->id.bus,

                              entry->id.device, ('A' + entry->pin), prt->source,

                              entry->link.index));

        spin_lock(&acpi_prt_lock);

        list_add_tail(&entry->node, &acpi_prt.entries);

        acpi_prt.count++;

        spin_unlock(&acpi_prt_lock);

        return 0;

}

static void

acpi_pci_irq_del_entry(int segment, int bus, struct acpi_prt_entry *entry)

{

        if (segment == entry->id.segment && bus == entry->id.bus) {

                acpi_prt.count--;

                list_del(&entry->node);

                kfree(entry);

        }

}

int acpi_pci_irq_add_prt(acpi_handle handle, int segment, int bus)

{

        acpi_status status = AE_OK;

        char *pathname = NULL;

        struct acpi_buffer buffer = { 0, NULL };

        struct acpi_pci_routing_table *prt = NULL;

        struct acpi_pci_routing_table *entry = NULL;

        static int first_time = 1;

        pathname = kzalloc(ACPI_PATHNAME_MAX, GFP_KERNEL);

        if (!pathname)

                return -ENOMEM;

        if (first_time) {

                acpi_prt.count = 0;

                INIT_LIST_HEAD(&acpi_prt.entries);

                first_time = 0;

        }

        /*

         * NOTE: We're given a 'handle' to the _PRT object's parent device

         *       (either a PCI root bridge or PCI-PCI bridge).

         */

        buffer.length = ACPI_PATHNAME_MAX;

        buffer.pointer = pathname;

        acpi_get_name(handle, ACPI_FULL_PATHNAME, &buffer);

        printk(KERN_DEBUG "ACPI: PCI Interrupt Routing Table [%s._PRT]\n",

               pathname);

        /*

         * Evaluate this _PRT and add its entries to our global list (acpi_prt).

         */

        buffer.length = 0;

        buffer.pointer = NULL;

        kfree(pathname);

        status = acpi_get_irq_routing_table(handle, &buffer);

        if (status != AE_BUFFER_OVERFLOW) {

                ACPI_EXCEPTION((AE_INFO, status, "Evaluating _PRT [%s]",

                                acpi_format_exception(status)));

                return -ENODEV;

        }

        prt = kzalloc(buffer.length, GFP_KERNEL);

        if (!prt) {

                return -ENOMEM;

        }

        buffer.pointer = prt;

        status = acpi_get_irq_routing_table(handle, &buffer);

        if (ACPI_FAILURE(status)) {

                ACPI_EXCEPTION((AE_INFO, status, "Evaluating _PRT [%s]",

                                acpi_format_exception(status)));

                kfree(buffer.pointer);

                return -ENODEV;

        }

        entry = prt;

        while (entry && (entry->length > 0)) {

                acpi_pci_irq_add_entry(handle, segment, bus, entry);

                entry = (struct acpi_pci_routing_table *)

                    ((unsigned long)entry + entry->length);

        }

        kfree(prt);

        return 0;

}

void acpi_pci_irq_del_prt(int segment, int bus)

{

        struct list_head *node = NULL, *n = NULL;

        struct acpi_prt_entry *entry = NULL;

        if (!acpi_prt.count) {

                return;

        }

        printk(KERN_DEBUG

               "ACPI: Delete PCI Interrupt Routing Table for %x:%x\n", segment,

               bus);

        spin_lock(&acpi_prt_lock);

        list_for_each_safe(node, n, &acpi_prt.entries) {

                entry = list_entry(node, struct acpi_prt_entry, node);

                acpi_pci_irq_del_entry(segment, bus, entry);

        }

        spin_unlock(&acpi_prt_lock);

}

/* --------------------------------------------------------------------------

                          PCI Interrupt Routing Support

   -------------------------------------------------------------------------- */

typedef int (*irq_lookup_func) (struct acpi_prt_entry *, int *, int *, char **);

static int

acpi_pci_allocate_irq(struct acpi_prt_entry *entry,

                      int *triggering, int *polarity, char **link)

{

        int irq;

        if (entry->link.handle) {

                irq = acpi_pci_link_allocate_irq(entry->link.handle,

                                                 entry->link.index, triggering,

                                                 polarity, link);

                if (irq < 0) {

                        printk(KERN_WARNING PREFIX

                                      "Invalid IRQ link routing entry\n");

                        return -1;

                }

        } else {

                irq = entry->link.index;

                *triggering = ACPI_LEVEL_SENSITIVE;

                *polarity = ACPI_ACTIVE_LOW;

        }

        ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Found IRQ %d\n", irq));

        return irq;

}

static int

acpi_pci_free_irq(struct acpi_prt_entry *entry,

                  int *triggering, int *polarity, char **link)

{

        int irq;

        if (entry->link.handle) {

                irq = acpi_pci_link_free_irq(entry->link.handle);

        } else {

                irq = entry->link.index;

        }

        return irq;

}

/*

 * acpi_pci_irq_lookup

 * success: return IRQ >= 0

 * failure: return -1

 */

static int

acpi_pci_irq_lookup(struct pci_bus *bus,

                    int device,

                    int pin,

                    int *triggering,

                    int *polarity, char **link, irq_lookup_func func)

{

        struct acpi_prt_entry *entry = NULL;

        int segment = pci_domain_nr(bus);

        int bus_nr = bus->number;

        int ret;

        ACPI_DEBUG_PRINT((ACPI_DB_INFO,

                          "Searching for PRT entry for %02x:%02x:%02x[%c]\n",

                          segment, bus_nr, device, ('A' + pin)));

        entry = acpi_pci_irq_find_prt_entry(segment, bus_nr, device, pin);

        if (!entry) {

                ACPI_DEBUG_PRINT((ACPI_DB_INFO, "PRT entry not found\n"));

                return -1;

        }

        ret = func(entry, triggering, polarity, link);

        return ret;

}

/*

 * acpi_pci_irq_derive

 * success: return IRQ >= 0

 * failure: return < 0

 */

static int

acpi_pci_irq_derive(struct pci_dev *dev,

                    int pin,

                    int *triggering,

                    int *polarity, char **link, irq_lookup_func func)

{

        struct pci_dev *bridge = dev;

        int irq = -1;

        u8 bridge_pin = 0;

        if (!dev)

                return -EINVAL;

        /*

         * Attempt to derive an IRQ for this device from a parent bridge's

         * PCI interrupt routing entry (eg. yenta bridge and add-in card bridge).

         */

        while (irq < 0 && bridge->bus->self) {

                pin = (pin + PCI_SLOT(bridge->devfn)) % 4;

                bridge = bridge->bus->self;

                if ((bridge->class >> 8) == PCI_CLASS_BRIDGE_CARDBUS) {

                        /* PC card has the same IRQ as its cardbridge */

                        bridge_pin = bridge->pin;

                        if (!bridge_pin) {

                                ACPI_DEBUG_PRINT((ACPI_DB_INFO,

                                                  "No interrupt pin configured for device %s\n",

                                                  pci_name(bridge)));

                                return -1;

                        }

                        /* Pin is from 0 to 3 */

                        bridge_pin--;

                        pin = bridge_pin;

                }

                irq = acpi_pci_irq_lookup(bridge->bus, PCI_SLOT(bridge->devfn),

                                          pin, triggering, polarity,

                                          link, func);

        }

        if (irq < 0) {

                printk(KERN_WARNING PREFIX "Unable to derive IRQ for device %s\n",

                              pci_name(dev));

                return -1;

        }

        ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Derive IRQ %d for device %s from %s\n",

                          irq, pci_name(dev), pci_name(bridge)));

        return irq;

}

/*

 * acpi_pci_irq_enable

 * success: return 0

 * failure: return < 0

 */

int acpi_pci_irq_enable(struct pci_dev *dev)

{

        int irq = 0;

        u8 pin = 0;

        int triggering = ACPI_LEVEL_SENSITIVE;

        int polarity = ACPI_ACTIVE_LOW;

        char *link = NULL;

        int rc;

        if (!dev)

                return -EINVAL;

        pin = dev->pin;

        if (!pin) {

                ACPI_DEBUG_PRINT((ACPI_DB_INFO,

                                  "No interrupt pin configured for device %s\n",

                                  pci_name(dev)));

                return 0;

        }

        pin--;

        if (!dev->bus) {

                printk(KERN_ERR PREFIX "Invalid (NULL) 'bus' field\n");

                return -ENODEV;

        }

        /*

         * First we check the PCI IRQ routing table (PRT) for an IRQ.  PRT

         * values override any BIOS-assigned IRQs set during boot.

         */

        irq = acpi_pci_irq_lookup(dev->bus, PCI_SLOT(dev->devfn), pin,

                                  &triggering, &polarity, &link,

                                  acpi_pci_allocate_irq);

        /*

         * If no PRT entry was found, we'll try to derive an IRQ from the

         * device's parent bridge.

         */

        if (irq < 0)

                irq = acpi_pci_irq_derive(dev, pin, &triggering,

                                          &polarity, &link,

                                          acpi_pci_allocate_irq);

        if (irq < 0) {

                /*

                 * IDE legacy mode controller IRQs are magic. Why do compat

                 * extensions always make such a nasty mess.

                 */

                if (dev->class >> 8 == PCI_CLASS_STORAGE_IDE &&

                                (dev->class & 0x05) == 0)

                        return 0;

        }

        /*

         * No IRQ known to the ACPI subsystem - maybe the BIOS /

         * driver reported one, then use it. Exit in any case.

         */

        if (irq < 0) {

                printk(KERN_WARNING PREFIX "PCI Interrupt %s[%c]: no GSI",

                       pci_name(dev), ('A' + pin));

                /* Interrupt Line values above 0xF are forbidden */

                if (dev->irq > 0 && (dev->irq <= 0xF)) {

                        printk(" - using IRQ %d\n", dev->irq);

                        acpi_register_gsi(dev->irq, ACPI_LEVEL_SENSITIVE,

                                          ACPI_ACTIVE_LOW);

                        return 0;

                } else {

                        printk("\n");

                        return 0;

                }

        }

        rc = acpi_register_gsi(irq, triggering, polarity);

        if (rc < 0) {

                printk(KERN_WARNING PREFIX "PCI Interrupt %s[%c]: failed "

                       "to register GSI\n", pci_name(dev), ('A' + pin));

                return rc;

        }

        dev->irq = rc;

        printk(KERN_INFO PREFIX "PCI Interrupt %s[%c] -> ",

               pci_name(dev), 'A' + pin);

        if (link)

                printk("Link [%s] -> ", link);

        printk("GSI %u (%s, %s) -> IRQ %d\n", irq,

               (triggering == ACPI_LEVEL_SENSITIVE) ? "level" : "edge",

               (polarity == ACPI_ACTIVE_LOW) ? "low" : "high", dev->irq);

        return 0;

}

EXPORT_SYMBOL(acpi_pci_irq_enable);

/* FIXME: implement x86/x86_64 version */

void __attribute__ ((weak)) acpi_unregister_gsi(u32 i)

{

}

void acpi_pci_irq_disable(struct pci_dev *dev)

{

        int gsi = 0;

        u8 pin = 0;

        int triggering = ACPI_LEVEL_SENSITIVE;

        int polarity = ACPI_ACTIVE_LOW;

        if (!dev || !dev->bus)

                return;

        pin = dev->pin;

        if (!pin)

                return;

        pin--;

        /*

         * First we check the PCI IRQ routing table (PRT) for an IRQ.

         */

        gsi = acpi_pci_irq_lookup(dev->bus, PCI_SLOT(dev->devfn), pin,

                                  &triggering, &polarity, NULL,

                                  acpi_pci_free_irq);

        /*

         * If no PRT entry was found, we'll try to derive an IRQ from the

         * device's parent bridge.

         */

        if (gsi < 0)

                gsi = acpi_pci_irq_derive(dev, pin,

                                          &triggering, &polarity, NULL,

                                          acpi_pci_free_irq);

        if (gsi < 0)

                return;

        /*

         * TBD: It might be worth clearing dev->irq by magic constant

         * (e.g. PCI_UNDEFINED_IRQ).

         */

        printk(KERN_INFO PREFIX "PCI interrupt for device %s disabled\n",

               pci_name(dev));

        acpi_unregister_gsi(gsi);

        return;

}