1 // SPDX-License-Identifier: GPL-2.0 2 /* uio_pci_generic - generic UIO driver for PCI 2.3 devices 3 * 4 * Copyright (C) 2009 Red Hat, Inc. 5 * Author: Michael S. Tsirkin <mst@redhat.com> 6 * 7 * Since the driver does not declare any device ids, you must allocate 8 * id and bind the device to the driver yourself. For example: 9 * 10 * # echo "8086 10f5" > /sys/bus/pci/drivers/uio_pci_generic/new_id 11 * # echo -n 0000:00:19.0 > /sys/bus/pci/drivers/e1000e/unbind 12 * # echo -n 0000:00:19.0 > /sys/bus/pci/drivers/uio_pci_generic/bind 13 * # ls -l /sys/bus/pci/devices/0000:00:19.0/driver 14 * .../0000:00:19.0/driver -> ../../../bus/pci/drivers/uio_pci_generic 15 * 16 * Driver won't bind to devices which do not support the Interrupt Disable Bit 17 * in the command register. All devices compliant to PCI 2.3 (circa 2002) and 18 * all compliant PCI Express devices should support this bit. 19 */ 20 21 #include <linux/device.h> 22 #include <linux/module.h> 23 #include <linux/pci.h> 24 #include <linux/slab.h> 25 #include <linux/uio_driver.h> 26 27 #define DRIVER_VERSION "0.01.0" 28 #define DRIVER_AUTHOR "Michael S. Tsirkin <mst@redhat.com>" 29 #define DRIVER_DESC "Generic UIO driver for PCI 2.3 devices" 30 31 struct uio_pci_generic_dev { 32 struct uio_info info; 33 struct pci_dev *pdev; 34 }; 35 36 static inline struct uio_pci_generic_dev * 37 to_uio_pci_generic_dev(struct uio_info *info) 38 { 39 return container_of(info, struct uio_pci_generic_dev, info); 40 } 41 42 static int release(struct uio_info *info, struct inode *inode) 43 { 44 struct uio_pci_generic_dev *gdev = to_uio_pci_generic_dev(info); 45 46 /* 47 * This driver is insecure when used with devices doing DMA, but some 48 * people (mis)use it with such devices. 49 * Let's at least make sure DMA isn't left enabled after the userspace 50 * driver closes the fd. 51 * Note that there's a non-zero chance doing this will wedge the device 52 * at least until reset. 53 */ 54 pci_clear_master(gdev->pdev); 55 return 0; 56 } 57 58 /* Interrupt handler. Read/modify/write the command register to disable 59 * the interrupt. */ 60 static irqreturn_t irqhandler(int irq, struct uio_info *info) 61 { 62 struct uio_pci_generic_dev *gdev = to_uio_pci_generic_dev(info); 63 64 if (!pci_check_and_mask_intx(gdev->pdev)) 65 return IRQ_NONE; 66 67 /* UIO core will signal the user process. */ 68 return IRQ_HANDLED; 69 } 70 71 static int probe(struct pci_dev *pdev, 72 const struct pci_device_id *id) 73 { 74 struct uio_pci_generic_dev *gdev; 75 int err; 76 77 err = pcim_enable_device(pdev); 78 if (err) { 79 dev_err(&pdev->dev, "%s: pci_enable_device failed: %d\n", 80 __func__, err); 81 return err; 82 } 83 84 if (pdev->irq && !pci_intx_mask_supported(pdev)) 85 return -ENOMEM; 86 87 gdev = devm_kzalloc(&pdev->dev, sizeof(struct uio_pci_generic_dev), GFP_KERNEL); 88 if (!gdev) 89 return -ENOMEM; 90 91 gdev->info.name = "uio_pci_generic"; 92 gdev->info.version = DRIVER_VERSION; 93 gdev->info.release = release; 94 gdev->pdev = pdev; 95 if (pdev->irq && (pdev->irq != IRQ_NOTCONNECTED)) { 96 gdev->info.irq = pdev->irq; 97 gdev->info.irq_flags = IRQF_SHARED; 98 gdev->info.handler = irqhandler; 99 } else { 100 dev_warn(&pdev->dev, "No IRQ assigned to device: " 101 "no support for interrupts?\n"); 102 } 103 104 return devm_uio_register_device(&pdev->dev, &gdev->info); 105 } 106 107 static struct pci_driver uio_pci_driver = { 108 .name = "uio_pci_generic", 109 .id_table = NULL, /* only dynamic id's */ 110 .probe = probe, 111 }; 112 113 module_pci_driver(uio_pci_driver); 114 MODULE_VERSION(DRIVER_VERSION); 115 MODULE_LICENSE("GPL v2"); 116 MODULE_AUTHOR(DRIVER_AUTHOR); 117 MODULE_DESCRIPTION(DRIVER_DESC); 118