diff options
Diffstat (limited to '')
| -rw-r--r-- | drivers/uio/uio_pci_generic.c | 142 |
1 files changed, 142 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..dde5cbb27 --- /dev/null +++ b/drivers/uio/uio_pci_generic.c @@ -0,0 +1,142 @@ +// 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 = pci_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)) { + err = -ENODEV; + goto err_verify; + } + + gdev = kzalloc(sizeof(struct uio_pci_generic_dev), GFP_KERNEL); + if (!gdev) { + err = -ENOMEM; + goto err_alloc; + } + + gdev->info.name = "uio_pci_generic"; + gdev->info.version = DRIVER_VERSION; + gdev->info.release = release; + gdev->pdev = pdev; + if (pdev->irq) { + 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"); + } + + err = uio_register_device(&pdev->dev, &gdev->info); + if (err) + goto err_register; + pci_set_drvdata(pdev, gdev); + + return 0; +err_register: + kfree(gdev); +err_alloc: +err_verify: + pci_disable_device(pdev); + return err; +} + +static void remove(struct pci_dev *pdev) +{ + struct uio_pci_generic_dev *gdev = pci_get_drvdata(pdev); + + uio_unregister_device(&gdev->info); + pci_disable_device(pdev); + kfree(gdev); +} + +static struct pci_driver uio_pci_driver = { + .name = "uio_pci_generic", + .id_table = NULL, /* only dynamic id's */ + .probe = probe, + .remove = remove, +}; + +module_pci_driver(uio_pci_driver); +MODULE_VERSION(DRIVER_VERSION); +MODULE_LICENSE("GPL v2"); +MODULE_AUTHOR(DRIVER_AUTHOR); +MODULE_DESCRIPTION(DRIVER_DESC); |