/* * drivers/usb/core/usb.c * * (C) Copyright Linus Torvalds 1999 * (C) Copyright Johannes Erdfelt 1999-2001 * (C) Copyright Andreas Gal 1999 * (C) Copyright Gregory P. Smith 1999 * (C) Copyright Deti Fliegl 1999 (new USB architecture) * (C) Copyright Randy Dunlap 2000 * (C) Copyright David Brownell 2000-2004 * (C) Copyright Yggdrasil Computing, Inc. 2000 * (usb_device_id matching changes by Adam J. Richter) * (C) Copyright Greg Kroah-Hartman 2002-2003 * * NOTE! This is not actually a driver at all, rather this is * just a collection of helper routines that implement the * generic USB things that the real drivers can use.. * * Think of this as a "USB library" rather than anything else. * It should be considered a slave, with no callbacks. Callbacks * are evil. */ #include <linux/module.h>#include <linux/moduleparam.h>#include <linux/string.h>#include <linux/bitops.h>#include <linux/slab.h>#include <linux/interrupt.h> /* for in_interrupt() */#include <linux/kmod.h>#include <linux/init.h>#include <linux/spinlock.h>#include <linux/errno.h>#include <linux/smp_lock.h>#include <linux/usb.h>#include <linux/mutex.h>#include <linux/workqueue.h> #include <asm/io.h>#include <asm/scatterlist.h>#include <linux/mm.h>#include <linux/dma-mapping.h> #include "hcd.h"#include "usb.h" const char *usbcore_name = "usbcore"; static int nousb; /* Disable USB when built into kernel image */ struct workqueue_struct *ksuspend_usb_wq; /* For autosuspend */ #ifdef CONFIG_USB_SUSPENDstatic int usb_autosuspend_delay = 2; /* Default delay value, * in seconds */module_param_named(autosuspend, usb_autosuspend_delay, uint, 0644);MODULE_PARM_DESC(autosuspend, "default autosuspend delay"); #else#define usb_autosuspend_delay 0#endif /** * usb_ifnum_to_if - get the interface object with a given interface number * @dev: the device whose current configuration is considered * @ifnum: the desired interface * * This walks the device descriptor for the currently active configuration * and returns a pointer to the interface with that particular interface * number, or null. * * Note that configuration descriptors are not required to assign interface * numbers sequentially, so that it would be incorrect to assume that * the first interface in that descriptor corresponds to interface zero. * This routine helps device drivers avoid such mistakes. * However, you should make sure that you do the right thing with any * alternate settings available for this interfaces. * * Don't call this function unless you are bound to one of the interfaces * on this device or you have locked the device! */struct usb_interface *usb_ifnum_to_if(const struct usb_device *dev, unsigned ifnum){ struct usb_host_config *config = dev->actconfig; int i; if (!config) return NULL; for (i = 0; i < config->desc.bNumInterfaces; i++) if (config->interface[i]->altsetting[0] .desc.bInterfaceNumber == ifnum) return config->interface[i]; return NULL;} /** * usb_altnum_to_altsetting - get the altsetting structure with a given * alternate setting number. * @intf: the interface containing the altsetting in question * @altnum: the desired alternate setting number * * This searches the altsetting array of the specified interface for * an entry with the correct bAlternateSetting value and returns a pointer * to that entry, or null. * * Note that altsettings need not be stored sequentially by number, so * it would be incorrect to assume that the first altsetting entry in * the array corresponds to altsetting zero. This routine helps device * drivers avoid such mistakes. * * Don't call this function unless you are bound to the intf interface * or you have locked the device! */struct usb_host_interface *usb_altnum_to_altsetting(const struct usb_interface *intf, unsigned int altnum){ int i; for (i = 0; i < intf->num_altsetting; i++) { if (intf->altsetting[i].desc.bAlternateSetting == altnum) return &intf->altsetting[i]; } return NULL;} struct find_interface_arg { int minor; struct usb_interface *interface;}; static int __find_interface(struct device * dev, void * data){ struct find_interface_arg *arg = data; struct usb_interface *intf; /* can't look at usb devices, only interfaces */ if (is_usb_device(dev)) return 0; intf = to_usb_interface(dev); if (intf->minor != -1 && intf->minor == arg->minor) { arg->interface = intf; return 1; } return 0;} /** * usb_find_interface - find usb_interface pointer for driver and device * @drv: the driver whose current configuration is considered * @minor: the minor number of the desired device * * This walks the driver device list and returns a pointer to the interface * with the matching minor. Note, this only works for devices that share the * USB major number. */struct usb_interface *usb_find_interface(struct usb_driver *drv, int minor){ struct find_interface_arg argb; int retval; argb.minor = minor; argb.interface = NULL; /* eat the error, it will be in argb.interface */ retval = driver_for_each_device(&drv->drvwrap.driver, NULL, &argb, __find_interface); return argb.interface;} /** * usb_release_dev - free a usb device structure when all users of it are finished. * @dev: device that's been disconnected * * Will be called only by the device core when all users of this usb device are * done. */static void usb_release_dev(struct device *dev){ struct usb_device *udev; udev = to_usb_device(dev); #ifdef CONFIG_USB_SUSPEND cancel_delayed_work(&udev->autosuspend); flush_workqueue(ksuspend_usb_wq);#endif usb_destroy_configuration(udev); usb_put_hcd(bus_to_hcd(udev->bus)); kfree(udev->product); kfree(udev->manufacturer); kfree(udev->serial); kfree(udev);} #ifdef CONFIG_PM static int ksuspend_usb_init(void){ ksuspend_usb_wq = create_singlethread_workqueue("ksuspend_usbd"); if (!ksuspend_usb_wq) return -ENOMEM; return 0;} static void ksuspend_usb_cleanup(void){ destroy_workqueue(ksuspend_usb_wq);} #ifdef CONFIG_USB_SUSPEND /* usb_autosuspend_work - callback routine to autosuspend a USB device */static void usb_autosuspend_work(struct work_struct *work){ struct usb_device *udev = container_of(work, struct usb_device, autosuspend.work); usb_pm_lock(udev); udev->auto_pm = 1; usb_suspend_both(udev, PMSG_SUSPEND); usb_pm_unlock(udev);} #else static void usb_autosuspend_work(struct work_struct *work){} #endif /* CONFIG_USB_SUSPEND */ #else #define ksuspend_usb_init() 0#define ksuspend_usb_cleanup() do {} while (0) #endif /* CONFIG_PM */ /** * usb_alloc_dev - usb device constructor (usbcore-internal) * @parent: hub to which device is connected; null to allocate a root hub * @bus: bus used to access the device * @port1: one-based index of port; ignored for root hubs * Context: !in_interrupt() * * Only hub drivers (including virtual root hub drivers for host * controllers) should ever call this. * * This call may not be used in a non-sleeping context. */struct usb_device *usb_alloc_dev(struct usb_device *parent, struct usb_bus *bus, unsigned port1){ struct usb_device *dev; dev = kzalloc(sizeof(*dev), GFP_KERNEL); if (!dev) return NULL; if (!usb_get_hcd(bus_to_hcd(bus))) { kfree(dev); return NULL; } device_initialize(&dev->dev); dev->dev.bus = &usb_bus_type; dev->dev.dma_mask = bus->controller->dma_mask; dev->dev.release = usb_release_dev; dev->state = USB_STATE_ATTACHED; /* This magic assignment distinguishes devices from interfaces */ dev->dev.platform_data = &usb_generic_driver; INIT_LIST_HEAD(&dev->ep0.urb_list); dev->ep0.desc.bLength = USB_DT_ENDPOINT_SIZE; dev->ep0.desc.bDescriptorType = USB_DT_ENDPOINT; /* ep0 maxpacket comes later, from device descriptor */ dev->ep_in[0] = dev->ep_out[0] = &dev->ep0; /* Save readable and stable topology id, distinguishing devices * by location for diagnostics, tools, driver model, etc. The * string is a path along hub ports, from the root. Each device's * dev->devpath will be stable until USB is re-cabled, and hubs * are often labeled with these port numbers. The bus_id isn't * as stable: bus->busnum changes easily from modprobe order, * cardbus or pci hotplugging, and so on. */ if (unlikely(!parent)) { dev->devpath[0] = '0'; dev->dev.parent = bus->controller; sprintf(&dev->dev.bus_id[0], "usb%d", bus->busnum); } else { /* match any labeling on the hubs; it's one-based */ if (parent->devpath[0] == '0') snprintf(dev->devpath, sizeof dev->devpath, "%d", port1); else snprintf(dev->devpath, sizeof dev->devpath, "%s.%d", parent->devpath, port1); dev->dev.parent = &parent->dev; sprintf(&dev->dev.bus_id[0], "%d-%s", bus->busnum, dev->devpath); /* hub driver sets up TT records */ } dev->portnum = port1; dev->bus = bus; dev->parent = parent; INIT_LIST_HEAD(&dev->filelist); #ifdef CONFIG_PM mutex_init(&dev->pm_mutex); INIT_DELAYED_WORK(&dev->autosuspend, usb_autosuspend_work); dev->autosuspend_delay = usb_autosuspend_delay * HZ;#endif return dev;} /** * usb_get_dev - increments the reference count of the usb device structure * @dev: the device being referenced * * Each live reference to a device should be refcounted. * * Drivers for USB interfaces should normally record such references in * their probe() methods, when they bind to an interface, and release * them by calling usb_put_dev(), in their disconnect() methods. * * A pointer to the device with the incremented reference counter is returned. */struct usb_device *usb_get_dev(struct usb_device *dev){ if (dev) get_device(&dev->dev); return dev;} /** * usb_put_dev - release a use of the usb device structure * @dev: device that's been disconnected * * Must be called when a user of a device is finished with it. When the last * user of the device calls this function, the memory of the device is freed. */void usb_put_dev(struct usb_device *dev){ if (dev) put_device(&dev->dev);} /** * usb_get_intf - increments the reference count of the usb interface structure * @intf: the interface being referenced * * Each live reference to a interface must be refcounted. * * Drivers for USB interfaces should normally record such references in * their probe() methods, when they bind to an interface, and release * them by calling usb_put_intf(), in their disconnect() methods. * * A pointer to the interface with the incremented reference counter is * returned. */struct usb_interface *usb_get_intf(struct usb_interface *intf){ if (intf) get_device(&intf->dev); return intf;} /** * usb_put_intf - release a use of the usb interface structure * @intf: interface that's been decremented * * Must be called when a user of an interface is finished with it. When the * last user of the interface calls this function, the memory of the interface * is freed. */void usb_put_intf(struct usb_interface *intf){ if (intf) put_device(&intf->dev);} /* USB device locking * * USB devices and interfaces are locked using the semaphore in their * embedded struct device. The hub driver guarantees that whenever a * device is connected or disconnected, drivers are called with the * USB device locked as well as their particular interface. * * Complications arise when several devices are to be locked at the same * time. Only hub-aware drivers that are part of usbcore ever have to * do this; nobody else needs to worry about it. The rule for locking * is simple: * * When locking both a device and its parent, always lock the * the parent first. */ /** * usb_lock_device_for_reset - cautiously acquire the lock for a * usb device structure * @udev: device that's being locked * @iface: interface bound to the driver making the request (optional) * * Attempts to acquire the device lock, but fails if the device is * NOTATTACHED or SUSPENDED, or if iface is specified and the interface * is neither BINDING nor BOUND. Rather than sleeping to wait for the * lock, the routine polls repeatedly. This is to prevent deadlock with * disconnect; in some drivers (such as usb-storage) the disconnect() * or suspend() method will block waiting for a device reset to complete. * * Returns a negative error code for failure, otherwise 1 or 0 to indicate * that the device will or will not have to be unlocked. (0 can be * returned when an interface is given and is BINDING, because in that * case the driver already owns the device lock.) */int usb_lock_device_for_reset(struct usb_device *udev, const struct usb_interface *iface){ unsigned long jiffies_expire = jiffies + HZ; if (udev->state == USB_STATE_NOTATTACHED) return -ENODEV; if (udev->state == USB_STATE_SUSPENDED) return -EHOSTUNREACH; if (iface) { switch (iface->condition) { case USB_INTERFACE_BINDING: return 0; case USB_INTERFACE_BOUND: break; default: return -EINTR; } } while (usb_trylock_device(udev) != 0) { /* If we can't acquire the lock after waiting one second, * we're probably deadlocked */ if (time_after(jiffies, jiffies_expire)) return -EBUSY; msleep(15); if (udev->state == USB_STATE_NOTATTACHED) return -ENODEV; if (udev->state == USB_STATE_SUSPENDED) return -EHOSTUNREACH; if (iface && iface->condition != USB_INTERFACE_BOUND) return -EINTR; } return 1;} static struct usb_device *match_device(struct usb_device *dev, u16 vendor_id, u16 product_id){ struct usb_device *ret_dev = NULL; int child; dev_dbg(&dev->dev, "check for vendor %04x, product %04x ...\n", le16_to_cpu(dev->descriptor.idVendor), le16_to_cpu(dev->descriptor.idProduct)); /* see if this device matches */ if ((vendor_id == le16_to_cpu(dev->descriptor.idVendor)) && (product_id == le16_to_cpu(dev->descriptor.idProduct))) { dev_dbg(&dev->dev, "matched this device!\n"); ret_dev = usb_get_dev(dev); goto exit; } /* look through all of the children of this device */ for (child = 0; child < dev->maxchild; ++child) { if (dev->children[child]) { usb_lock_device(dev->children[child]); ret_dev = match_device(dev->children[child], vendor_id, product_id); usb_unlock_device(dev->children[child]); if (ret_dev) goto exit; } }exit: return ret_dev;} /** * usb_find_device - find a specific usb device in the system * @vendor_id: the vendor id of the device to findLines 1–500 of 1001. 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/* * drivers/usb/core/usb.c * * (C) Copyright Linus Torvalds 1999 * (C) Copyright Johannes Erdfelt 1999-2001 * (C) Copyright Andreas Gal 1999 * (C) Copyright Gregory P. Smith 1999 * (C) Copyright Deti Fliegl 1999 (new USB architecture) * (C) Copyright Randy Dunlap 2000 * (C) Copyright David Brownell 2000-2004 * (C) Copyright Yggdrasil Computing, Inc. 2000 * (usb_device_id matching changes by Adam J. Richter) * (C) Copyright Greg Kroah-Hartman 2002-2003 * * NOTE! This is not actually a driver at all, rather this is * just a collection of helper routines that implement the * generic USB things that the real drivers can use.. * * Think of this as a "USB library" rather than anything else. * It should be considered a slave, with no callbacks. Callbacks * are evil. */ #include <linux/module.h> #include <linux/moduleparam.h> #include <linux/string.h> #include <linux/bitops.h> #include <linux/slab.h> #include <linux/interrupt.h> /* for in_interrupt() */ #include <linux/kmod.h> #include <linux/init.h> #include <linux/spinlock.h> #include <linux/errno.h> #include <linux/smp_lock.h> #include <linux/usb.h> #include <linux/mutex.h> #include <linux/workqueue.h> #include <asm/io.h> #include <asm/scatterlist.h> #include <linux/mm.h> #include <linux/dma-mapping.h> #include "hcd.h" #include "usb.h" const char *usbcore_name = "usbcore"; static int nousb; /* Disable USB when built into kernel image */ struct workqueue_struct *ksuspend_usb_wq; /* For autosuspend */ #ifdef CONFIG_USB_SUSPEND static int usb_autosuspend_delay = 2; /* Default delay value, * in seconds */ module_param_named(autosuspend, usb_autosuspend_delay, uint, 0644); MODULE_PARM_DESC(autosuspend, "default autosuspend delay"); #else #define usb_autosuspend_delay 0 #endif /** * usb_ifnum_to_if - get the interface object with a given interface number * @dev: the device whose current configuration is considered * @ifnum: the desired interface * * This walks the device descriptor for the currently active configuration * and returns a pointer to the interface with that particular interface * number, or null. * * Note that configuration descriptors are not required to assign interface * numbers sequentially, so that it would be incorrect to assume that * the first interface in that descriptor corresponds to interface zero. * This routine helps device drivers avoid such mistakes. * However, you should make sure that you do the right thing with any * alternate settings available for this interfaces. * * Don't call this function unless you are bound to one of the interfaces * on this device or you have locked the device! */ struct usb_interface *usb_ifnum_to_if(const struct usb_device *dev, unsigned ifnum) { struct usb_host_config *config = dev->actconfig; int i; if (!config) return NULL; for (i = 0; i < config->desc.bNumInterfaces; i++) if (config->interface[i]->altsetting[0] .desc.bInterfaceNumber == ifnum) return config->interface[i]; return NULL; } /** * usb_altnum_to_altsetting - get the altsetting structure with a given * alternate setting number. * @intf: the interface containing the altsetting in question * @altnum: the desired alternate setting number * * This searches the altsetting array of the specified interface for * an entry with the correct bAlternateSetting value and returns a pointer * to that entry, or null. * * Note that altsettings need not be stored sequentially by number, so * it would be incorrect to assume that the first altsetting entry in * the array corresponds to altsetting zero. This routine helps device * drivers avoid such mistakes. * * Don't call this function unless you are bound to the intf interface * or you have locked the device! */ struct usb_host_interface *usb_altnum_to_altsetting(const struct usb_interface *intf, unsigned int altnum) { int i; for (i = 0; i < intf->num_altsetting; i++) { if (intf->altsetting[i].desc.bAlternateSetting == altnum) return &intf->altsetting[i]; } return NULL; } struct find_interface_arg { int minor; struct usb_interface *interface; }; static int __find_interface(struct device * dev, void * data) { struct find_interface_arg *arg = data; struct usb_interface *intf; /* can't look at usb devices, only interfaces */ if (is_usb_device(dev)) return 0; intf = to_usb_interface(dev); if (intf->minor != -1 && intf->minor == arg->minor) { arg->interface = intf; return 1; } return 0; } /** * usb_find_interface - find usb_interface pointer for driver and device * @drv: the driver whose current configuration is considered * @minor: the minor number of the desired device * * This walks the driver device list and returns a pointer to the interface * with the matching minor. Note, this only works for devices that share the * USB major number. */ struct usb_interface *usb_find_interface(struct usb_driver *drv, int minor) { struct find_interface_arg argb; int retval; argb.minor = minor; argb.interface = NULL; /* eat the error, it will be in argb.interface */ retval = driver_for_each_device(&drv->drvwrap.driver, NULL, &argb, __find_interface); return argb.interface; } /** * usb_release_dev - free a usb device structure when all users of it are finished. * @dev: device that's been disconnected * * Will be called only by the device core when all users of this usb device are * done. */ static void usb_release_dev(struct device *dev) { struct usb_device *udev; udev = to_usb_device(dev); #ifdef CONFIG_USB_SUSPEND cancel_delayed_work(&udev->autosuspend); flush_workqueue(ksuspend_usb_wq); #endif usb_destroy_configuration(udev); usb_put_hcd(bus_to_hcd(udev->bus)); kfree(udev->product); kfree(udev->manufacturer); kfree(udev->serial); kfree(udev); } #ifdef CONFIG_PM static int ksuspend_usb_init(void) { ksuspend_usb_wq = create_singlethread_workqueue("ksuspend_usbd"); if (!ksuspend_usb_wq) return -ENOMEM; return 0; } static void ksuspend_usb_cleanup(void) { destroy_workqueue(ksuspend_usb_wq); } #ifdef CONFIG_USB_SUSPEND /* usb_autosuspend_work - callback routine to autosuspend a USB device */ static void usb_autosuspend_work(struct work_struct *work) { struct usb_device *udev = container_of(work, struct usb_device, autosuspend.work); usb_pm_lock(udev); udev->auto_pm = 1; usb_suspend_both(udev, PMSG_SUSPEND); usb_pm_unlock(udev); } #else static void usb_autosuspend_work(struct work_struct *work) {} #endif /* CONFIG_USB_SUSPEND */ #else #define ksuspend_usb_init() 0 #define ksuspend_usb_cleanup() do {} while (0) #endif /* CONFIG_PM */ /** * usb_alloc_dev - usb device constructor (usbcore-internal) * @parent: hub to which device is connected; null to allocate a root hub * @bus: bus used to access the device * @port1: one-based index of port; ignored for root hubs * Context: !in_interrupt() * * Only hub drivers (including virtual root hub drivers for host * controllers) should ever call this. * * This call may not be used in a non-sleeping context. */ struct usb_device * usb_alloc_dev(struct usb_device *parent, struct usb_bus *bus, unsigned port1) { struct usb_device *dev; dev = kzalloc(sizeof(*dev), GFP_KERNEL); if (!dev) return NULL; if (!usb_get_hcd(bus_to_hcd(bus))) { kfree(dev); return NULL; } device_initialize(&dev->dev); dev->dev.bus = &usb_bus_type; dev->dev.dma_mask = bus->controller->dma_mask; dev->dev.release = usb_release_dev; dev->state = USB_STATE_ATTACHED; /* This magic assignment distinguishes devices from interfaces */ dev->dev.platform_data = &usb_generic_driver; INIT_LIST_HEAD(&dev->ep0.urb_list); dev->ep0.desc.bLength = USB_DT_ENDPOINT_SIZE; dev->ep0.desc.bDescriptorType = USB_DT_ENDPOINT; /* ep0 maxpacket comes later, from device descriptor */ dev->ep_in[0] = dev->ep_out[0] = &dev->ep0; /* Save readable and stable topology id, distinguishing devices * by location for diagnostics, tools, driver model, etc. The * string is a path along hub ports, from the root. Each device's * dev->devpath will be stable until USB is re-cabled, and hubs * are often labeled with these port numbers. The bus_id isn't * as stable: bus->busnum changes easily from modprobe order, * cardbus or pci hotplugging, and so on. */ if (unlikely(!parent)) { dev->devpath[0] = '0'; dev->dev.parent = bus->controller; sprintf(&dev->dev.bus_id[0], "usb%d", bus->busnum); } else { /* match any labeling on the hubs; it's one-based */ if (parent->devpath[0] == '0') snprintf(dev->devpath, sizeof dev->devpath, "%d", port1); else snprintf(dev->devpath, sizeof dev->devpath, "%s.%d", parent->devpath, port1); dev->dev.parent = &parent->dev; sprintf(&dev->dev.bus_id[0], "%d-%s", bus->busnum, dev->devpath); /* hub driver sets up TT records */ } dev->portnum = port1; dev->bus = bus; dev->parent = parent; INIT_LIST_HEAD(&dev->filelist); #ifdef CONFIG_PM mutex_init(&dev->pm_mutex); INIT_DELAYED_WORK(&dev->autosuspend, usb_autosuspend_work); dev->autosuspend_delay = usb_autosuspend_delay * HZ; #endif return dev; } /** * usb_get_dev - increments the reference count of the usb device structure * @dev: the device being referenced * * Each live reference to a device should be refcounted. * * Drivers for USB interfaces should normally record such references in * their probe() methods, when they bind to an interface, and release * them by calling usb_put_dev(), in their disconnect() methods. * * A pointer to the device with the incremented reference counter is returned. */ struct usb_device *usb_get_dev(struct usb_device *dev) { if (dev) get_device(&dev->dev); return dev; } /** * usb_put_dev - release a use of the usb device structure * @dev: device that's been disconnected * * Must be called when a user of a device is finished with it. When the last * user of the device calls this function, the memory of the device is freed. */ void usb_put_dev(struct usb_device *dev) { if (dev) put_device(&dev->dev); } /** * usb_get_intf - increments the reference count of the usb interface structure * @intf: the interface being referenced * * Each live reference to a interface must be refcounted. * * Drivers for USB interfaces should normally record such references in * their probe() methods, when they bind to an interface, and release * them by calling usb_put_intf(), in their disconnect() methods. * * A pointer to the interface with the incremented reference counter is * returned. */ struct usb_interface *usb_get_intf(struct usb_interface *intf) { if (intf) get_device(&intf->dev); return intf; } /** * usb_put_intf - release a use of the usb interface structure * @intf: interface that's been decremented * * Must be called when a user of an interface is finished with it. When the * last user of the interface calls this function, the memory of the interface * is freed. */ void usb_put_intf(struct usb_interface *intf) { if (intf) put_device(&intf->dev); } /* USB device locking * * USB devices and interfaces are locked using the semaphore in their * embedded struct device. The hub driver guarantees that whenever a * device is connected or disconnected, drivers are called with the * USB device locked as well as their particular interface. * * Complications arise when several devices are to be locked at the same * time. Only hub-aware drivers that are part of usbcore ever have to * do this; nobody else needs to worry about it. The rule for locking * is simple: * * When locking both a device and its parent, always lock the * the parent first. */ /** * usb_lock_device_for_reset - cautiously acquire the lock for a * usb device structure * @udev: device that's being locked * @iface: interface bound to the driver making the request (optional) * * Attempts to acquire the device lock, but fails if the device is * NOTATTACHED or SUSPENDED, or if iface is specified and the interface * is neither BINDING nor BOUND. Rather than sleeping to wait for the * lock, the routine polls repeatedly. This is to prevent deadlock with * disconnect; in some drivers (such as usb-storage) the disconnect() * or suspend() method will block waiting for a device reset to complete. * * Returns a negative error code for failure, otherwise 1 or 0 to indicate * that the device will or will not have to be unlocked. (0 can be * returned when an interface is given and is BINDING, because in that * case the driver already owns the device lock.) */ int usb_lock_device_for_reset(struct usb_device *udev, const struct usb_interface *iface) { unsigned long jiffies_expire = jiffies + HZ; if (udev->state == USB_STATE_NOTATTACHED) return -ENODEV; if (udev->state == USB_STATE_SUSPENDED) return -EHOSTUNREACH; if (iface) { switch (iface->condition) { case USB_INTERFACE_BINDING: return 0; case USB_INTERFACE_BOUND: break; default: return -EINTR; } } while (usb_trylock_device(udev) != 0) { /* If we can't acquire the lock after waiting one second, * we're probably deadlocked */ if (time_after(jiffies, jiffies_expire)) return -EBUSY; msleep(15); if (udev->state == USB_STATE_NOTATTACHED) return -ENODEV; if (udev->state == USB_STATE_SUSPENDED) return -EHOSTUNREACH; if (iface && iface->condition != USB_INTERFACE_BOUND) return -EINTR; } return 1; } static struct usb_device *match_device(struct usb_device *dev, u16 vendor_id, u16 product_id) { struct usb_device *ret_dev = NULL; int child; dev_dbg(&dev->dev, "check for vendor %04x, product %04x ...\n", le16_to_cpu(dev->descriptor.idVendor), le16_to_cpu(dev->descriptor.idProduct)); /* see if this device matches */ if ((vendor_id == le16_to_cpu(dev->descriptor.idVendor)) && (product_id == le16_to_cpu(dev->descriptor.idProduct))) { dev_dbg(&dev->dev, "matched this device!\n"); ret_dev = usb_get_dev(dev); goto exit; } /* look through all of the children of this device */ for (child = 0; child < dev->maxchild; ++child) { if (dev->children[child]) { usb_lock_device(dev->children[child]); ret_dev = match_device(dev->children[child], vendor_id, product_id); usb_unlock_device(dev->children[child]); if (ret_dev) goto exit; } } exit: return ret_dev; } /** * usb_find_device - find a specific usb device in the system * @vendor_id: the vendor id of the device to find