drivers/uio/uio_pci_generic.c

   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
  32 struct uio_pci_generic_dev {
  33         struct uio_info info;
  34         struct pci_dev *pdev;
  35 };
  36
  37 static inline struct uio_pci_generic_dev *
  38 to_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. */
  45 static 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
  56 static int 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         err = uio_register_device(&pdev->dev, &gdev->info);
  95         if (err)
  96                 goto err_register;
  97         pci_set_drvdata(pdev, gdev);
  98
  99         return 0;
 100 err_register:
 101         kfree(gdev);
 102 err_alloc:
 103 err_verify:
 104         pci_disable_device(pdev);
 105         return err;
 106 }
 107
 108 static void remove(struct pci_dev *pdev)
 109 {
 110         struct uio_pci_generic_dev *gdev = pci_get_drvdata(pdev);
 111
 112         uio_unregister_device(&gdev->info);
 113         pci_disable_device(pdev);
 114         kfree(gdev);
 115 }
 116
 117 static struct pci_driver uio_pci_driver = {
 118         .name = "uio_pci_generic",
 119         .id_table = NULL, /* only dynamic id's */
 120         .probe = probe,
 121         .remove = remove,
 122 };
 123
 124 module_pci_driver(uio_pci_driver);
 125 MODULE_VERSION(DRIVER_VERSION);
 126 MODULE_LICENSE("GPL v2");
 127 MODULE_AUTHOR(DRIVER_AUTHOR);
 128 MODULE_DESCRIPTION(DRIVER_DESC);