| // 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); |