linux/drivers/pci/ioapic.c
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   1/*
   2 * IOAPIC/IOxAPIC/IOSAPIC driver
   3 *
   4 * Copyright (C) 2009 Fujitsu Limited.
   5 * (c) Copyright 2009 Hewlett-Packard Development Company, L.P.
   6 *
   7 * This program is free software; you can redistribute it and/or modify
   8 * it under the terms of the GNU General Public License version 2 as
   9 * published by the Free Software Foundation.
  10 */
  11
  12/*
  13 * This driver manages PCI I/O APICs added by hotplug after boot.  We try to
  14 * claim all I/O APIC PCI devices, but those present at boot were registered
  15 * when we parsed the ACPI MADT, so we'll fail when we try to re-register
  16 * them.
  17 */
  18
  19#include <linux/pci.h>
  20#include <linux/acpi.h>
  21#include <linux/slab.h>
  22#include <acpi/acpi_bus.h>
  23
  24struct ioapic {
  25        acpi_handle     handle;
  26        u32             gsi_base;
  27};
  28
  29static int ioapic_probe(struct pci_dev *dev, const struct pci_device_id *ent)
  30{
  31        acpi_handle handle;
  32        acpi_status status;
  33        unsigned long long gsb;
  34        struct ioapic *ioapic;
  35        int ret;
  36        char *type;
  37        struct resource *res;
  38
  39        handle = DEVICE_ACPI_HANDLE(&dev->dev);
  40        if (!handle)
  41                return -EINVAL;
  42
  43        status = acpi_evaluate_integer(handle, "_GSB", NULL, &gsb);
  44        if (ACPI_FAILURE(status))
  45                return -EINVAL;
  46
  47        /*
  48         * The previous code in acpiphp evaluated _MAT if _GSB failed, but
  49         * ACPI spec 4.0 sec 6.2.2 requires _GSB for hot-pluggable I/O APICs.
  50         */
  51
  52        ioapic = kzalloc(sizeof(*ioapic), GFP_KERNEL);
  53        if (!ioapic)
  54                return -ENOMEM;
  55
  56        ioapic->handle = handle;
  57        ioapic->gsi_base = (u32) gsb;
  58
  59        if (dev->class == PCI_CLASS_SYSTEM_PIC_IOAPIC)
  60                type = "IOAPIC";
  61        else
  62                type = "IOxAPIC";
  63
  64        ret = pci_enable_device(dev);
  65        if (ret < 0)
  66                goto exit_free;
  67
  68        pci_set_master(dev);
  69
  70        if (pci_request_region(dev, 0, type))
  71                goto exit_disable;
  72
  73        res = &dev->resource[0];
  74        if (acpi_register_ioapic(ioapic->handle, res->start, ioapic->gsi_base))
  75                goto exit_release;
  76
  77        pci_set_drvdata(dev, ioapic);
  78        dev_info(&dev->dev, "%s at %pR, GSI %u\n", type, res, ioapic->gsi_base);
  79        return 0;
  80
  81exit_release:
  82        pci_release_region(dev, 0);
  83exit_disable:
  84        pci_disable_device(dev);
  85exit_free:
  86        kfree(ioapic);
  87        return -ENODEV;
  88}
  89
  90static void ioapic_remove(struct pci_dev *dev)
  91{
  92        struct ioapic *ioapic = pci_get_drvdata(dev);
  93
  94        acpi_unregister_ioapic(ioapic->handle, ioapic->gsi_base);
  95        pci_release_region(dev, 0);
  96        pci_disable_device(dev);
  97        kfree(ioapic);
  98}
  99
 100
 101static struct pci_device_id ioapic_devices[] = {
 102        { PCI_ANY_ID, PCI_ANY_ID, PCI_ANY_ID, PCI_ANY_ID,
 103          PCI_CLASS_SYSTEM_PIC_IOAPIC << 8, 0xffff00, },
 104        { PCI_ANY_ID, PCI_ANY_ID, PCI_ANY_ID, PCI_ANY_ID,
 105          PCI_CLASS_SYSTEM_PIC_IOXAPIC << 8, 0xffff00, },
 106        { }
 107};
 108
 109static struct pci_driver ioapic_driver = {
 110        .name           = "ioapic",
 111        .id_table       = ioapic_devices,
 112        .probe          = ioapic_probe,
 113        .remove         = __devexit_p(ioapic_remove),
 114};
 115
 116static int __init ioapic_init(void)
 117{
 118        return pci_register_driver(&ioapic_driver);
 119}
 120
 121static void __exit ioapic_exit(void)
 122{
 123        pci_unregister_driver(&ioapic_driver);
 124}
 125
 126module_init(ioapic_init);
 127module_exit(ioapic_exit);
 128