// 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 = pcim_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)) return -ENODEV; gdev = devm_kzalloc(&pdev->dev, sizeof(struct uio_pci_generic_dev), GFP_KERNEL); if (!gdev) return -ENOMEM; gdev->info.name = "uio_pci_generic"; gdev->info.version = DRIVER_VERSION; gdev->info.release = release; gdev->pdev = pdev; if (pdev->irq && (pdev->irq != IRQ_NOTCONNECTED)) { 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"); } return devm_uio_register_device(&pdev->dev, &gdev->info); } static struct pci_driver uio_pci_driver = { .name = "uio_pci_generic", .id_table = NULL, /* only dynamic id's */ .probe = probe, }; module_pci_driver(uio_pci_driver); MODULE_VERSION(DRIVER_VERSION); MODULE_LICENSE("GPL v2"); MODULE_AUTHOR(DRIVER_AUTHOR); MODULE_DESCRIPTION(DRIVER_DESC);