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pci_irq.c

/*
 *  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;
}

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