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// SPDX-License-Identifier: GPL-2.0
/* uio_pci_generic - generic UIO driver for PCI 2.3 devices
*
* Copyright (C) 2009 Red Hat, Inc.
* Author: Michael S. Tsirkin <mst@redhat.com>
*
* Since the driver does not declare any device ids, you must allocate
* id and bind the device to the driver yourself. For example:
*
* # echo "8086 10f5" > /sys/bus/pci/drivers/uio_pci_generic/new_id
* # echo -n 0000:00:19.0 > /sys/bus/pci/drivers/e1000e/unbind
* # echo -n 0000:00:19.0 > /sys/bus/pci/drivers/uio_pci_generic/bind
* # ls -l /sys/bus/pci/devices/0000:00:19.0/driver
* .../0000:00:19.0/driver -> ../../../bus/pci/drivers/uio_pci_generic
*
* Driver won't bind to devices which do not support the Interrupt Disable Bit
* in the command register. All devices compliant to PCI 2.3 (circa 2002) and
* all compliant PCI Express devices should support this bit.
*/
#include <linux/device.h>
#include <linux/module.h>
#include <linux/pci.h>
#include <linux/slab.h>
#include <linux/uio_driver.h>
#define DRIVER_VERSION "0.01.0"
#define DRIVER_AUTHOR "Michael S. Tsirkin <mst@redhat.com>"
#define DRIVER_DESC "Generic UIO driver for PCI 2.3 devices"
struct uio_pci_generic_dev {
struct uio_info info;
struct pci_dev *pdev;
};
static inline struct uio_pci_generic_dev *
to_uio_pci_generic_dev(struct uio_info *info)
{
return container_of(info, struct uio_pci_generic_dev, info);
}
static int release(struct uio_info *info, struct inode *inode)
{
struct uio_pci_generic_dev *gdev = to_uio_pci_generic_dev(info);
/*
* This driver is insecure when used with devices doing DMA, but some
* people (mis)use it with such devices.
* Let's at least make sure DMA isn't left enabled after the userspace
* driver closes the fd.
* Note that there's a non-zero chance doing this will wedge the device
* at least until reset.
*/
pci_clear_master(gdev->pdev);
return 0;
}
/* Interrupt handler. Read/modify/write the command register to disable
* the interrupt. */
static irqreturn_t irqhandler(int irq, struct uio_info *info)
{
struct uio_pci_generic_dev *gdev = to_uio_pci_generic_dev(info);
if (!pci_check_and_mask_intx(gdev->pdev))
return IRQ_NONE;
/* UIO core will signal the user process. */
return IRQ_HANDLED;
}
static int probe(struct pci_dev *pdev,
const struct pci_device_id *id)
{
struct uio_pci_generic_dev *gdev;
int err;
err = pci_enable_device(pdev);
if (err) {
dev_err(&pdev->dev, "%s: pci_enable_device failed: %d\n",
__func__, err);
return err;
}
if (pdev->irq && !pci_intx_mask_supported(pdev)) {
err = -ENODEV;
goto err_verify;
}
gdev = kzalloc(sizeof(struct uio_pci_generic_dev), GFP_KERNEL);
if (!gdev) {
err = -ENOMEM;
goto err_alloc;
}
gdev->info.name = "uio_pci_generic";
gdev->info.version = DRIVER_VERSION;
gdev->info.release = release;
gdev->pdev = pdev;
if (pdev->irq) {
gdev->info.irq = pdev->irq;
gdev->info.irq_flags = IRQF_SHARED;
gdev->info.handler = irqhandler;
} else {
dev_warn(&pdev->dev, "No IRQ assigned to device: "
"no support for interrupts?\n");
}
err = uio_register_device(&pdev->dev, &gdev->info);
if (err)
goto err_register;
pci_set_drvdata(pdev, gdev);
return 0;
err_register:
kfree(gdev);
err_alloc:
err_verify:
pci_disable_device(pdev);
return err;
}
static void remove(struct pci_dev *pdev)
{
struct uio_pci_generic_dev *gdev = pci_get_drvdata(pdev);
uio_unregister_device(&gdev->info);
pci_disable_device(pdev);
kfree(gdev);
}
static struct pci_driver uio_pci_driver = {
.name = "uio_pci_generic",
.id_table = NULL, /* only dynamic id's */
.probe = probe,
.remove = remove,
};
module_pci_driver(uio_pci_driver);
MODULE_VERSION(DRIVER_VERSION);
MODULE_LICENSE("GPL v2");
MODULE_AUTHOR(DRIVER_AUTHOR);
MODULE_DESCRIPTION(DRIVER_DESC);
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