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 /* Interrupt handler. Read/modify/write the command register to disable 43 * the interrupt. */ 44 static irqreturn_t irqhandler(int irq, struct uio_info *info) 45 { 46 struct uio_pci_generic_dev *gdev = to_uio_pci_generic_dev(info); 47 48 if (!pci_check_and_mask_intx(gdev->pdev)) 49 return IRQ_NONE; 50 51 /* UIO core will signal the user process. */ 52 return IRQ_HANDLED; 53 } 54 55 static int probe(struct pci_dev *pdev, 56 const struct pci_device_id *id) 57 { 58 struct uio_pci_generic_dev *gdev; 59 int err; 60 61 err = pci_enable_device(pdev); 62 if (err) { 63 dev_err(&pdev->dev, "%s: pci_enable_device failed: %d\n", 64 __func__, err); 65 return err; 66 } 67 68 if (pdev->irq && !pci_intx_mask_supported(pdev)) { 69 err = -ENODEV; 70 goto err_verify; 71 } 72 73 gdev = kzalloc(sizeof(struct uio_pci_generic_dev), GFP_KERNEL); 74 if (!gdev) { 75 err = -ENOMEM; 76 goto err_alloc; 77 } 78 79 gdev->info.name = "uio_pci_generic"; 80 gdev->info.version = DRIVER_VERSION; 81 gdev->pdev = pdev; 82 if (pdev->irq) { 83 gdev->info.irq = pdev->irq; 84 gdev->info.irq_flags = IRQF_SHARED; 85 gdev->info.handler = irqhandler; 86 } else { 87 dev_warn(&pdev->dev, "No IRQ assigned to device: " 88 "no support for interrupts?\n"); 89 } 90 91 err = uio_register_device(&pdev->dev, &gdev->info); 92 if (err) 93 goto err_register; 94 pci_set_drvdata(pdev, gdev); 95 96 return 0; 97 err_register: 98 kfree(gdev); 99 err_alloc: 100 err_verify: 101 pci_disable_device(pdev); 102 return err; 103 } 104 105 static void remove(struct pci_dev *pdev) 106 { 107 struct uio_pci_generic_dev *gdev = pci_get_drvdata(pdev); 108 109 uio_unregister_device(&gdev->info); 110 pci_disable_device(pdev); 111 kfree(gdev); 112 } 113 114 static struct pci_driver uio_pci_driver = { 115 .name = "uio_pci_generic", 116 .id_table = NULL, /* only dynamic id's */ 117 .probe = probe, 118 .remove = remove, 119 }; 120 121 module_pci_driver(uio_pci_driver); 122 MODULE_VERSION(DRIVER_VERSION); 123 MODULE_LICENSE("GPL v2"); 124 MODULE_AUTHOR(DRIVER_AUTHOR); 125 MODULE_DESCRIPTION(DRIVER_DESC); 126