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 struct uio_mem *uiomem; 76 int err; 77 int i; 78 79 err = pcim_enable_device(pdev); 80 if (err) { 81 dev_err(&pdev->dev, "%s: pci_enable_device failed: %d\n", 82 __func__, err); 83 return err; 84 } 85 86 if (pdev->irq && !pci_intx_mask_supported(pdev)) 87 return -ENODEV; 88 89 gdev = devm_kzalloc(&pdev->dev, sizeof(struct uio_pci_generic_dev), GFP_KERNEL); 90 if (!gdev) 91 return -ENOMEM; 92 93 gdev->info.name = "uio_pci_generic"; 94 gdev->info.version = DRIVER_VERSION; 95 gdev->info.release = release; 96 gdev->pdev = pdev; 97 if (pdev->irq && (pdev->irq != IRQ_NOTCONNECTED)) { 98 gdev->info.irq = pdev->irq; 99 gdev->info.irq_flags = IRQF_SHARED; 100 gdev->info.handler = irqhandler; 101 } else { 102 dev_warn(&pdev->dev, "No IRQ assigned to device: " 103 "no support for interrupts?\n"); 104 } 105 106 uiomem = &gdev->info.mem[0]; 107 for (i = 0; i < MAX_UIO_MAPS; ++i) { 108 struct resource *r = &pdev->resource[i]; 109 110 if (r->flags != (IORESOURCE_SIZEALIGN | IORESOURCE_MEM)) 111 continue; 112 113 if (uiomem >= &gdev->info.mem[MAX_UIO_MAPS]) { 114 dev_warn( 115 &pdev->dev, 116 "device has more than " __stringify( 117 MAX_UIO_MAPS) " I/O memory resources.\n"); 118 break; 119 } 120 121 uiomem->memtype = UIO_MEM_PHYS; 122 uiomem->addr = r->start & PAGE_MASK; 123 uiomem->offs = r->start & ~PAGE_MASK; 124 uiomem->size = 125 (uiomem->offs + resource_size(r) + PAGE_SIZE - 1) & 126 PAGE_MASK; 127 uiomem->name = r->name; 128 ++uiomem; 129 } 130 131 while (uiomem < &gdev->info.mem[MAX_UIO_MAPS]) { 132 uiomem->size = 0; 133 ++uiomem; 134 } 135 136 return devm_uio_register_device(&pdev->dev, &gdev->info); 137 } 138 139 static struct pci_driver uio_pci_driver = { 140 .name = "uio_pci_generic", 141 .id_table = NULL, /* only dynamic id's */ 142 .probe = probe, 143 }; 144 145 module_pci_driver(uio_pci_driver); 146 MODULE_VERSION(DRIVER_VERSION); 147 MODULE_LICENSE("GPL v2"); 148 MODULE_AUTHOR(DRIVER_AUTHOR); 149 MODULE_DESCRIPTION(DRIVER_DESC); 150