diff options
Diffstat (limited to 'drivers/uio/uio_pci_generic.c')
| -rw-r--r-- | drivers/uio/uio_pci_generic.c | 149 |
1 files changed, 149 insertions, 0 deletions
diff --git a/drivers/uio/uio_pci_generic.c b/drivers/uio/uio_pci_generic.c new file mode 100644 index 000000000..e03f9b532 --- /dev/null +++ b/drivers/uio/uio_pci_generic.c @@ -0,0 +1,149 @@ +// 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; + struct uio_mem *uiomem; + int err; + int i; + + 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"); + } + + uiomem = &gdev->info.mem[0]; + for (i = 0; i < MAX_UIO_MAPS; ++i) { + struct resource *r = &pdev->resource[i]; + + if (r->flags != (IORESOURCE_SIZEALIGN | IORESOURCE_MEM)) + continue; + + if (uiomem >= &gdev->info.mem[MAX_UIO_MAPS]) { + dev_warn( + &pdev->dev, + "device has more than " __stringify( + MAX_UIO_MAPS) " I/O memory resources.\n"); + break; + } + + uiomem->memtype = UIO_MEM_PHYS; + uiomem->addr = r->start & PAGE_MASK; + uiomem->offs = r->start & ~PAGE_MASK; + uiomem->size = + (uiomem->offs + resource_size(r) + PAGE_SIZE - 1) & + PAGE_MASK; + uiomem->name = r->name; + ++uiomem; + } + + while (uiomem < &gdev->info.mem[MAX_UIO_MAPS]) { + uiomem->size = 0; + ++uiomem; + } + + 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); |