drivers/pci/ioapic.c

   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/module.h>
  21 #include <linux/acpi.h>
  22 #include <linux/slab.h>
  23
  24 struct ioapic {
  25         acpi_handle     handle;
  26         u32             gsi_base;
  27 };
  28
  29 static 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 = 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
  81 exit_release:
  82         pci_release_region(dev, 0);
  83 exit_disable:
  84         pci_disable_device(dev);
  85 exit_free:
  86         kfree(ioapic);
  87         return -ENODEV;
  88 }
  89
  90 static 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
 101 static const struct pci_device_id ioapic_devices[] = {
 102         { PCI_DEVICE_CLASS(PCI_CLASS_SYSTEM_PIC_IOAPIC, ~0) },
 103         { PCI_DEVICE_CLASS(PCI_CLASS_SYSTEM_PIC_IOXAPIC, ~0) },
 104         { }
 105 };
 106 MODULE_DEVICE_TABLE(pci, ioapic_devices);
 107
 108 static struct pci_driver ioapic_driver = {
 109         .name           = "ioapic",
 110         .id_table       = ioapic_devices,
 111         .probe          = ioapic_probe,
 112         .remove         = ioapic_remove,
 113 };
 114
 115 static int __init ioapic_init(void)
 116 {
 117         return pci_register_driver(&ioapic_driver);
 118 }
 119 module_init(ioapic_init);
 120
 121 MODULE_LICENSE("GPL");