linux/drivers/uio/uio_pci_generic.c
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   1/* uio_pci_generic - generic UIO driver for PCI 2.3 devices
   2 *
   3 * Copyright (C) 2009 Red Hat, Inc.
   4 * Author: Michael S. Tsirkin <mst@redhat.com>
   5 *
   6 * This work is licensed under the terms of the GNU GPL, version 2.
   7 *
   8 * Since the driver does not declare any device ids, you must allocate
   9 * id and bind the device to the driver yourself.  For example:
  10 *
  11 * # echo "8086 10f5" > /sys/bus/pci/drivers/uio_pci_generic/new_id
  12 * # echo -n 0000:00:19.0 > /sys/bus/pci/drivers/e1000e/unbind
  13 * # echo -n 0000:00:19.0 > /sys/bus/pci/drivers/uio_pci_generic/bind
  14 * # ls -l /sys/bus/pci/devices/0000:00:19.0/driver
  15 * .../0000:00:19.0/driver -> ../../../bus/pci/drivers/uio_pci_generic
  16 *
  17 * Driver won't bind to devices which do not support the Interrupt Disable Bit
  18 * in the command register. All devices compliant to PCI 2.3 (circa 2002) and
  19 * all compliant PCI Express devices should support this bit.
  20 */
  21
  22#include <linux/device.h>
  23#include <linux/module.h>
  24#include <linux/pci.h>
  25#include <linux/slab.h>
  26#include <linux/uio_driver.h>
  27
  28#define DRIVER_VERSION  "0.01.0"
  29#define DRIVER_AUTHOR   "Michael S. Tsirkin <mst@redhat.com>"
  30#define DRIVER_DESC     "Generic UIO driver for PCI 2.3 devices"
  31
  32struct uio_pci_generic_dev {
  33        struct uio_info info;
  34        struct pci_dev *pdev;
  35};
  36
  37static inline struct uio_pci_generic_dev *
  38to_uio_pci_generic_dev(struct uio_info *info)
  39{
  40        return container_of(info, struct uio_pci_generic_dev, info);
  41}
  42
  43/* Interrupt handler. Read/modify/write the command register to disable
  44 * the interrupt. */
  45static irqreturn_t irqhandler(int irq, struct uio_info *info)
  46{
  47        struct uio_pci_generic_dev *gdev = to_uio_pci_generic_dev(info);
  48
  49        if (!pci_check_and_mask_intx(gdev->pdev))
  50                return IRQ_NONE;
  51
  52        /* UIO core will signal the user process. */
  53        return IRQ_HANDLED;
  54}
  55
  56static int __devinit probe(struct pci_dev *pdev,
  57                           const struct pci_device_id *id)
  58{
  59        struct uio_pci_generic_dev *gdev;
  60        int err;
  61
  62        err = pci_enable_device(pdev);
  63        if (err) {
  64                dev_err(&pdev->dev, "%s: pci_enable_device failed: %d\n",
  65                        __func__, err);
  66                return err;
  67        }
  68
  69        if (!pdev->irq) {
  70                dev_warn(&pdev->dev, "No IRQ assigned to device: "
  71                         "no support for interrupts?\n");
  72                pci_disable_device(pdev);
  73                return -ENODEV;
  74        }
  75
  76        if (!pci_intx_mask_supported(pdev)) {
  77                err = -ENODEV;
  78                goto err_verify;
  79        }
  80
  81        gdev = kzalloc(sizeof(struct uio_pci_generic_dev), GFP_KERNEL);
  82        if (!gdev) {
  83                err = -ENOMEM;
  84                goto err_alloc;
  85        }
  86
  87        gdev->info.name = "uio_pci_generic";
  88        gdev->info.version = DRIVER_VERSION;
  89        gdev->info.irq = pdev->irq;
  90        gdev->info.irq_flags = IRQF_SHARED;
  91        gdev->info.handler = irqhandler;
  92        gdev->pdev = pdev;
  93
  94        if (uio_register_device(&pdev->dev, &gdev->info))
  95                goto err_register;
  96        pci_set_drvdata(pdev, gdev);
  97
  98        return 0;
  99err_register:
 100        kfree(gdev);
 101err_alloc:
 102err_verify:
 103        pci_disable_device(pdev);
 104        return err;
 105}
 106
 107static void remove(struct pci_dev *pdev)
 108{
 109        struct uio_pci_generic_dev *gdev = pci_get_drvdata(pdev);
 110
 111        uio_unregister_device(&gdev->info);
 112        pci_disable_device(pdev);
 113        kfree(gdev);
 114}
 115
 116static struct pci_driver driver = {
 117        .name = "uio_pci_generic",
 118        .id_table = NULL, /* only dynamic id's */
 119        .probe = probe,
 120        .remove = remove,
 121};
 122
 123static int __init init(void)
 124{
 125        pr_info(DRIVER_DESC " version: " DRIVER_VERSION "\n");
 126        return pci_register_driver(&driver);
 127}
 128
 129static void __exit cleanup(void)
 130{
 131        pci_unregister_driver(&driver);
 132}
 133
 134module_init(init);
 135module_exit(cleanup);
 136
 137MODULE_VERSION(DRIVER_VERSION);
 138MODULE_LICENSE("GPL v2");
 139MODULE_AUTHOR(DRIVER_AUTHOR);
 140MODULE_DESCRIPTION(DRIVER_DESC);
 141
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