SUNRPC: Fix a potential race in rpc_wake_up_task()

[linux-2.6/mini2440.git] / drivers / acpi / 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 = kmalloc(sizeof(struct acpi_prt_entry), GFP_KERNEL);
        if (!entry)
                return -ENOMEM;
        memset(entry, 0, sizeof(struct acpi_prt_entry));

        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 = (char *)kmalloc(ACPI_PATHNAME_MAX, GFP_KERNEL);
        if (!pathname)
                return -ENOMEM;
        memset(pathname, 0, ACPI_PATHNAME_MAX);

        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 = kmalloc(buffer.length, GFP_KERNEL);
        if (!prt) {
                return -ENOMEM;
        }
        memset(prt, 0, buffer.length);
        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);

        /*
         * 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;
}