linux驱动移植-usb总线设备驱动

/**
 * struct bus_type - The bus type of the device
 *
 * @name:       The name of the bus.
 * @dev_name:   Used for subsystems to enumerate devices like ("foo%u", dev->id).
 * @dev_root:   Default device to use as the parent.
 * @bus_groups: Default attributes of the bus.
 * @dev_groups: Default attributes of the devices on the bus.
 * @drv_groups: Default attributes of the device drivers on the bus.
 * @match:      Called, perhaps multiple times, whenever a new device or driver
 *              is added for this bus. It should return a positive value if the
 *              given device can be handled by the given driver and zero
 *              otherwise. It may also return error code if determining that
 *              the driver supports the device is not possible. In case of
 *              -EPROBE_DEFER it will queue the device for deferred probing.
 * @uevent:     Called when a device is added, removed, or a few other things
 *              that generate uevents to add the environment variables.
 * @probe:      Called when a new device or driver add to this bus, and callback
 *              the specific driver's probe to initial the matched device.
 * @remove:     Called when a device removed from this bus.
 * @shutdown:   Called at shut-down time to quiesce the device.
 *
 * @online:     Called to put the device back online (after offlining it).
 * @offline:    Called to put the device offline for hot-removal. May fail.
 *
 * @suspend:    Called when a device on this bus wants to go to sleep mode.
 * @resume:     Called to bring a device on this bus out of sleep mode.
 * @num_vf:     Called to find out how many virtual functions a device on this
 *              bus supports.
 * @dma_configure:      Called to setup DMA configuration on a device on
 *                      this bus.
 * @pm:         Power management operations of this bus, callback the specific
 *              device driver's pm-ops.
 * @iommu_ops:  IOMMU specific operations for this bus, used to attach IOMMU
 *              driver implementations to a bus and allow the driver to do
 *              bus-specific setup
 * @p:          The private data of the driver core, only the driver core can
 *              touch this.
 * @lock_key:   Lock class key for use by the lock validator
 * @need_parent_lock:   When probing or removing a device on this bus, the
 *                      device core should lock the device's parent.
 *
 * A bus is a channel between the processor and one or more devices. For the
 * purposes of the device model, all devices are connected via a bus, even if
 * it is an internal, virtual, "platform" bus. Buses can plug into each other.
 * A USB controller is usually a PCI device, for example. The device model
 * represents the actual connections between buses and the devices they control.
 * A bus is represented by the bus_type structure. It contains the name, the
 * default attributes, the bus' methods, PM operations, and the driver core's
 * private data.
 */
struct bus_type {
        const char              *name;
        const char              *dev_name;
        struct device           *dev_root;
        const struct attribute_group **bus_groups;
        const struct attribute_group **dev_groups;
        const struct attribute_group **drv_groups;

        int (*match)(struct device *dev, struct device_driver *drv);
        int (*uevent)(struct device *dev, struct kobj_uevent_env *env);
        int (*probe)(struct device *dev);
        int (*remove)(struct device *dev);
        void (*shutdown)(struct device *dev);

        int (*online)(struct device *dev);
        int (*offline)(struct device *dev);

        int (*suspend)(struct device *dev, pm_message_t state);
        int (*resume)(struct device *dev);

        int (*num_vf)(struct device *dev);

        int (*dma_configure)(struct device *dev);

        const struct dev_pm_ops *pm;

        const struct iommu_ops *iommu_ops;

        struct subsys_private *p;
        struct lock_class_key lock_key;

        bool need_parent_lock;
};

struct bus_type usb_bus_type = {
        .name =         "usb",
        .match =        usb_device_match,
        .uevent =       usb_uevent,
        .need_parent_lock =     true,
};

static int usb_device_match(struct device *dev, struct device_driver *drv)
{
        /* devices and interfaces are handled separately */
        if (is_usb_device(dev)) {

                /* interface drivers never match devices */
                if (!is_usb_device_driver(drv))
                        return 0;

                /* TODO: Add real matching code */
                return 1;

        } else if (is_usb_interface(dev)) {
                struct usb_interface *intf;
                struct usb_driver *usb_drv;
                const struct usb_device_id *id;

                /* device drivers never match interfaces */
                if (is_usb_device_driver(drv))
                        return 0;

                intf = to_usb_interface(dev);
                usb_drv = to_usb_driver(drv);

                id = usb_match_id(intf, usb_drv->id_table);
                if (id)
                        return 1;

                id = usb_match_dynamic_id(intf, usb_drv);
                if (id)
                        return 1;
        }

        return 0;
}

struct usbdrv_wrap {
    struct device_driver driver;
    int for_devices;
}

subsys_initcall(usb_init);
module_exit(usb_exit);

/*
 * Init
 */
static int __init usb_init(void)
{
        int retval;
        if (usb_disabled()) {
                pr_info("%s: USB support disabledn", usbcore_name);
                return 0;
        }
        usb_init_pool_max();

        usb_debugfs_init();

        usb_acpi_register();
        retval = bus_register(&usb_bus_type);
        if (retval)
                goto bus_register_failed;
        retval = bus_register_notifier(&usb_bus_type, &usb_bus_nb);
        if (retval)
                goto bus_notifier_failed;
        retval = usb_major_init();
        if (retval)
                goto major_init_failed;
        retval = usb_register(&usbfs_driver);
        if (retval)
                goto driver_register_failed;
        retval = usb_devio_init();
        if (retval)
                goto usb_devio_init_failed;
        retval = usb_hub_init();
        if (retval)
                goto hub_init_failed;
        retval = usb_register_device_driver(&usb_generic_driver, THIS_MODULE);
        if (!retval)
                goto out;

        usb_hub_cleanup();
hub_init_failed:
        usb_devio_cleanup();
usb_devio_init_failed:
        usb_deregister(&usbfs_driver);
driver_register_failed:
        usb_major_cleanup();
major_init_failed:
        bus_unregister_notifier(&usb_bus_type, &usb_bus_nb);
bus_notifier_failed:
        bus_unregister(&usb_bus_type);
bus_register_failed:
        usb_acpi_unregister();
        usb_debugfs_cleanup();
out:
        return retval;
}

static void usb_debugfs_init(void)
{
        usb_debug_root = debugfs_create_dir("usb", NULL);
        debugfs_create_file("devices", 0444, usb_debug_root, NULL,
                            &usbfs_devices_fops);
}

mount -t debugfs none $(debugfs) 

struct bus_type usb_bus_type = {
        .name =         "usb",
        .match =        usb_device_match,
        .uevent =       usb_uevent,
        .need_parent_lock =     true,
};

klist_init(&priv->klist_devices, klist_devices_get, klist_devices_put);
klist_init(&priv->klist_drivers, NULL, NULL);

root@zhengyang:/work/sambashare/linux-5.2.8# ls /sys/bus/usb
devices  drivers  drivers_autoprobe  drivers_probe  uevent

root@zhengyang:/work/sambashare/linux-5.2.8# ls /sys/bus/usb/devices
1-0:1.0  2-0:1.0  2-1  2-1:1.0  2-2  2-2.1  2-2:1.0  2-2.1:1.0  2-2.1:1.1  usb1  usb2
root@zhengyang:/work/sambashare/linux-5.2.8# ls /sys/bus/usb/drivers
btusb  hub  usb  usbfs  usbhid

int bus_register_notifier(struct bus_type *bus, struct notifier_block *nb)
{
        return blocking_notifier_chain_register(&bus->p->bus_notifier, nb);
}

static struct notifier_block usb_bus_nb = {
        .notifier_call = usb_bus_notify,
};

/*
 * Notifications of device and interface registration
 */
static int usb_bus_notify(struct notifier_block *nb, unsigned long action,
                void *data)
{
        struct device *dev = data;

        switch (action) {
        case BUS_NOTIFY_ADD_DEVICE:       // 添加设备
                if (dev->type == &usb_device_type)   // usb设备
                        (void) usb_create_sysfs_dev_files(to_usb_device(dev));
                else if (dev->type == &usb_if_device_type)   // usb接口
                        usb_create_sysfs_intf_files(to_usb_interface(dev));
                break;

        case BUS_NOTIFY_DEL_DEVICE:          // 删除设备
                if (dev->type == &usb_device_type)   // usb设备
                        usb_remove_sysfs_dev_files(to_usb_device(dev));
                else if (dev->type == &usb_if_device_type)  // usb接口
                        usb_remove_sysfs_intf_files(to_usb_interface(dev));
                break;
        }
        return 0;
}

int usb_major_init(void)
{
        int error;

        error = register_chrdev(USB_MAJOR, "usb", &usb_fops);
        if (error)
                printk(KERN_ERR "Unable to get major %d for usb devicesn",
                       USB_MAJOR);

        return error;
}

static const struct file_operations usb_fops = {
        .owner =        THIS_MODULE,
        .open =         usb_open,
        .llseek =       noop_llseek,
};

struct usb_driver usbfs_driver = {
        .name =         "usbfs",
        .probe =        driver_probe,
        .disconnect =   driver_disconnect,
        .suspend =      driver_suspend,
        .resume =       driver_resume,
};

/* use a define to avoid include chaining to get THIS_MODULE & friends */
#define usb_register(driver) 
        usb_register_driver(driver, THIS_MODULE, KBUILD_MODNAME)

/**
 * usb_register_driver - register a USB interface driver
 * @new_driver: USB operations for the interface driver
 * @owner: module owner of this driver.
 * @mod_name: module name string
 *
 * Registers a USB interface driver with the USB core.  The list of
 * unattached interfaces will be rescanned whenever a new driver is
 * added, allowing the new driver to attach to any recognized interfaces.
 *
 * Return: A negative error code on failure and 0 on success.
 *
 * NOTE: if you want your driver to use the USB major number, you must call
 * usb_register_dev() to enable that functionality.  This function no longer
 * takes care of that.
 */
int usb_register_driver(struct usb_driver *new_driver, struct module *owner,
                        const char *mod_name)
{
        int retval = 0;

        if (usb_disabled())
                return -ENODEV;

        new_driver->drvwrap.for_devices = 0;
        new_driver->drvwrap.driver.name = new_driver->name;
        new_driver->drvwrap.driver.bus = &usb_bus_type;
        new_driver->drvwrap.driver.probe = usb_probe_interface;
        new_driver->drvwrap.driver.remove = usb_unbind_interface;
        new_driver->drvwrap.driver.owner = owner;
        new_driver->drvwrap.driver.mod_name = mod_name;
        spin_lock_init(&new_driver->dynids.lock);
        INIT_LIST_HEAD(&new_driver->dynids.list);

        retval = driver_register(&new_driver->drvwrap.driver);
        if (retval)
                goto out;

        retval = usb_create_newid_files(new_driver);
        if (retval)
                goto out_newid;

        pr_info("%s: registered new interface driver %sn",
                        usbcore_name, new_driver->name);

out:
        return retval;

out_newid:
        driver_unregister(&new_driver->drvwrap.driver);

        printk(KERN_ERR "%s: error %d registering interface "
                        "       driver %sn",
                        usbcore_name, retval, new_driver->name);
        goto out;
}

int __init usb_devio_init(void)
{
        int retval;

        retval = register_chrdev_region(USB_DEVICE_DEV, USB_DEVICE_MAX,
                                        "usb_device");
        if (retval) {
                printk(KERN_ERR "Unable to register minors for usb_devicen");
                goto out;
        }
        cdev_init(&usb_device_cdev, &usbdev_file_operations);
        retval = cdev_add(&usb_device_cdev, USB_DEVICE_DEV, USB_DEVICE_MAX);
        if (retval) {
                printk(KERN_ERR "Unable to get usb_device major %dn",
                       USB_DEVICE_MAJOR);
                goto error_cdev;
        }
        usb_register_notify(&usbdev_nb);
out:
        return retval;

error_cdev:
        unregister_chrdev_region(USB_DEVICE_DEV, USB_DEVICE_MAX);
        goto out;
}

:#define USB_DEVICE_MAX                      (USB_MAXBUS * 128)  // 一个USB主机控制器，最多接入128个usb设备

static struct notifier_block usbdev_nb = {
        .notifier_call =        usbdev_notify,
};

/**
 * usb_register_notify - register a notifier callback whenever a usb change happens
 * @nb: pointer to the notifier block for the callback events.
 *
 * These changes are either USB devices or busses being added or removed.
 */
void usb_register_notify(struct notifier_block *nb)
{
        blocking_notifier_chain_register(&usb_notifier_list, nb);
}

static BLOCKING_NOTIFIER_HEAD(usb_notifier_list);

void usb_notify_add_device(struct usb_device *udev)
{
        blocking_notifier_call_chain(&usb_notifier_list, USB_DEVICE_ADD, udev);
}

void usb_notify_remove_device(struct usb_device *udev)
{
        /* Protect against simultaneous usbfs open */
        mutex_lock(&usbfs_mutex);
        blocking_notifier_call_chain(&usb_notifier_list,
                        USB_DEVICE_REMOVE, udev);
        mutex_unlock(&usbfs_mutex);
}

void usb_notify_add_bus(struct usb_bus *ubus)
{
        blocking_notifier_call_chain(&usb_notifier_list, USB_BUS_ADD, ubus);
}

void usb_notify_remove_bus(struct usb_bus *ubus)
{
        blocking_notifier_call_chain(&usb_notifier_list, USB_BUS_REMOVE, ubus);
}

static int usbdev_notify(struct notifier_block *self,
                               unsigned long action, void *dev)
{
        switch (action) {
        case USB_DEVICE_ADD:  // 设备添加
                break;
        case USB_DEVICE_REMOVE:  // 设备删除
                usbdev_remove(dev);
                break;
        }
        return NOTIFY_OK;
}

int usb_hub_init(void)
{
        if (usb_register(&hub_driver) < 0) {
                printk(KERN_ERR "%s: can't register hub drivern",
                        usbcore_name);
                return -1;
        }

        /*
         * The workqueue needs to be freezable to avoid interfering with
         * USB-PERSIST port handover. Otherwise it might see that a full-speed
         * device was gone before the EHCI controller had handed its port
         * over to the companion full-speed controller.
         */
        hub_wq = alloc_workqueue("usb_hub_wq", WQ_FREEZABLE, 0);
        if (hub_wq)
                return 0;

        /* Fall through if kernel_thread failed */
        usb_deregister(&hub_driver);
        pr_err("%s: can't allocate workqueue for usb hubn", usbcore_name);

        return -1;
}

static struct usb_driver hub_driver = {
        .name =         "hub",
        .probe =        hub_probe,
        .disconnect =   hub_disconnect,
        .suspend =      hub_suspend,
        .resume =       hub_resume,
        .reset_resume = hub_reset_resume,
        .pre_reset =    hub_pre_reset,
        .post_reset =   hub_post_reset,
        .unlocked_ioctl = hub_ioctl,
        .id_table =     hub_id_table,
        .supports_autosuspend = 1,
};

struct usb_device_driver usb_generic_driver = {
        .name = "usb",
        .probe = generic_probe,
        .disconnect = generic_disconnect,
#ifdef  CONFIG_PM
        .suspend = generic_suspend,
        .resume = generic_resume,
#endif
        .supports_autosuspend = 1,
};

/**
 * usb_register_device_driver - register a USB device (not interface) driver
 * @new_udriver: USB operations for the device driver
 * @owner: module owner of this driver.
 *
 * Registers a USB device driver with the USB core.  The list of
 * unattached devices will be rescanned whenever a new driver is
 * added, allowing the new driver to attach to any recognized devices.
 *
 * Return: A negative error code on failure and 0 on success.
 */
int usb_register_device_driver(struct usb_device_driver *new_udriver,
                struct module *owner)
{
        int retval = 0;

        if (usb_disabled())
                return -ENODEV;

        new_udriver->drvwrap.for_devices = 1;
        new_udriver->drvwrap.driver.name = new_udriver->name;
        new_udriver->drvwrap.driver.bus = &usb_bus_type;
        new_udriver->drvwrap.driver.probe = usb_probe_device;
        new_udriver->drvwrap.driver.remove = usb_unbind_device;
        new_udriver->drvwrap.driver.owner = owner;

        retval = driver_register(&new_udriver->drvwrap.driver);

        if (!retval)
                pr_info("%s: registered new device driver %sn",
                        usbcore_name, new_udriver->name);
        else
                printk(KERN_ERR "%s: error %d registering device "
                        "       driver %sn",
                        usbcore_name, retval, new_udriver->name);

        return retval;
}

/**
 * struct usb_driver - identifies USB interface driver to usbcore
 * @name: The driver name should be unique among USB drivers,
 *      and should normally be the same as the module name.
 * @probe: Called to see if the driver is willing to manage a particular
 *      interface on a device.  If it is, probe returns zero and uses
 *      usb_set_intfdata() to associate driver-specific data with the
 *      interface.  It may also use usb_set_interface() to specify the
 *      appropriate altsetting.  If unwilling to manage the interface,
 *      return -ENODEV, if genuine IO errors occurred, an appropriate
 *      negative errno value.
 * @disconnect: Called when the interface is no longer accessible, usually
 *      because its device has been (or is being) disconnected or the
 *      driver module is being unloaded.
 * @unlocked_ioctl: Used for drivers that want to talk to userspace through
 *      the "usbfs" filesystem.  This lets devices provide ways to
 *      expose information to user space regardless of where they
 *      do (or don't) show up otherwise in the filesystem.
 * @suspend: Called when the device is going to be suspended by the
 *      system either from system sleep or runtime suspend context. The
 *      return value will be ignored in system sleep context, so do NOT
 *      try to continue using the device if suspend fails in this case.
 *      Instead, let the resume or reset-resume routine recover from
 *      the failure.
 * @resume: Called when the device is being resumed by the system.
 * @reset_resume: Called when the suspended device has been reset instead
 *      of being resumed.
 * @pre_reset: Called by usb_reset_device() when the device is about to be
 *      reset.  This routine must not return until the driver has no active
 *      URBs for the device, and no more URBs may be submitted until the
 *      post_reset method is called.
 * @post_reset: Called by usb_reset_device() after the device
 *      has been reset
 * @id_table: USB drivers use ID table to support hotplugging.
 *      Export this with MODULE_DEVICE_TABLE(usb,...).  This must be set
 *      or your driver's probe function will never get called.
 * @dynids: used internally to hold the list of dynamically added device
 *      ids for this driver.
 * @drvwrap: Driver-model core structure wrapper.
 * @no_dynamic_id: if set to 1, the USB core will not allow dynamic ids to be
 *      added to this driver by preventing the sysfs file from being created.
 * @supports_autosuspend: if set to 0, the USB core will not allow autosuspend
 *      for interfaces bound to this driver.
 * @soft_unbind: if set to 1, the USB core will not kill URBs and disable
 *      endpoints before calling the driver's disconnect method.
 * @disable_hub_initiated_lpm: if set to 1, the USB core will not allow hubs
 *      to initiate lower power link state transitions when an idle timeout
 *      occurs.  Device-initiated USB 3.0 link PM will still be allowed.
 *
 * USB interface drivers must provide a name, probe() and disconnect()
 * methods, and an id_table.  Other driver fields are optional.
 *
 * The id_table is used in hotplugging.  It holds a set of descriptors,
 * and specialized data may be associated with each entry.  That table
 * is used by both user and kernel mode hotplugging support.
 *
 * The probe() and disconnect() methods are called in a context where
 * they can sleep, but they should avoid abusing the privilege.  Most
 * work to connect to a device should be done when the device is opened,
 * and undone at the last close.  The disconnect code needs to address
 * concurrency issues with respect to open() and close() methods, as
 * well as forcing all pending I/O requests to complete (by unlinking
 * them as necessary, and blocking until the unlinks complete).
 */
struct usb_driver {
        const char *name;

        int (*probe) (struct usb_interface *intf,
                      const struct usb_device_id *id);

        void (*disconnect) (struct usb_interface *intf);

        int (*unlocked_ioctl) (struct usb_interface *intf, unsigned int code,
                        void *buf);

        int (*suspend) (struct usb_interface *intf, pm_message_t message);
        int (*resume) (struct usb_interface *intf);
        int (*reset_resume)(struct usb_interface *intf);

        int (*pre_reset)(struct usb_interface *intf);
        int (*post_reset)(struct usb_interface *intf);

        const struct usb_device_id *id_table;

        struct usb_dynids dynids;
        struct usbdrv_wrap drvwrap;
        unsigned int no_dynamic_id:1;
        unsigned int supports_autosuspend:1;
        unsigned int disable_hub_initiated_lpm:1;
        unsigned int soft_unbind:1;
};

/**
 * usb_deregister - unregister a USB interface driver
 * @driver: USB operations of the interface driver to unregister
 * Context: must be able to sleep
 *
 * Unlinks the specified driver from the internal USB driver list.
 *
 * NOTE: If you called usb_register_dev(), you still need to call
 * usb_deregister_dev() to clean up your driver's allocated minor numbers,
 * this * call will no longer do it for you.
 */
void usb_deregister(struct usb_driver *driver)
{
        pr_info("%s: deregistering interface driver %sn",
                        usbcore_name, driver->name);

        usb_remove_newid_files(driver);
        driver_unregister(&driver->drvwrap.driver);
        usb_free_dynids(driver);
}

/**
 * struct usb_device_driver - identifies USB device driver to usbcore
 * @name: The driver name should be unique among USB drivers,
 *      and should normally be the same as the module name.
 * @probe: Called to see if the driver is willing to manage a particular
 *      device.  If it is, probe returns zero and uses dev_set_drvdata()
 *      to associate driver-specific data with the device.  If unwilling
 *      to manage the device, return a negative errno value.
 * @disconnect: Called when the device is no longer accessible, usually
 *      because it has been (or is being) disconnected or the driver's
 *      module is being unloaded.
 * @suspend: Called when the device is going to be suspended by the system.
 * @resume: Called when the device is being resumed by the system.
 * @drvwrap: Driver-model core structure wrapper.
 * @supports_autosuspend: if set to 0, the USB core will not allow autosuspend
 *      for devices bound to this driver.
 *
 * USB drivers must provide all the fields listed above except drvwrap.
 */
struct usb_device_driver {
        const char *name;

        int (*probe) (struct usb_device *udev);
        void (*disconnect) (struct usb_device *udev);

        int (*suspend) (struct usb_device *udev, pm_message_t message);
        int (*resume) (struct usb_device *udev, pm_message_t message);
        struct usbdrv_wrap drvwrap;
        unsigned int supports_autosuspend:1;
};

/**
 * usb_deregister_device_driver - unregister a USB device (not interface) driver
 * @udriver: USB operations of the device driver to unregister
 * Context: must be able to sleep
 *
 * Unlinks the specified driver from the internal USB driver list.
 */
void usb_deregister_device_driver(struct usb_device_driver *udriver)
{
        pr_info("%s: deregistering device driver %sn",
                        usbcore_name, udriver->name);

        driver_unregister(&udriver->drvwrap.driver);
}