#include <linux/spinlock.h>
#include <linux/errno.h>
#include <linux/smp_lock.h>
-#include <linux/rwsem.h>
#include <linux/usb.h>
#include <asm/io.h>
const char *usbcore_name = "usbcore";
static int nousb; /* Disable USB when built into kernel image */
- /* Not honored on modular build */
-
-static DECLARE_RWSEM(usb_all_devices_rwsem);
/**
mark_quiesced(iface);
}
+struct find_interface_arg {
+ int minor;
+ struct usb_interface *interface;
+};
+
static int __find_interface(struct device * dev, void * data)
{
- struct usb_interface ** ret = (struct usb_interface **)data;
- struct usb_interface * intf = *ret;
- int *minor = (int *)data;
+ struct find_interface_arg *arg = data;
+ struct usb_interface *intf;
/* can't look at usb devices, only interfaces */
if (dev->driver == &usb_generic_driver)
return 0;
intf = to_usb_interface(dev);
- if (intf->minor != -1 && intf->minor == *minor) {
- *ret = intf;
+ if (intf->minor != -1 && intf->minor == arg->minor) {
+ arg->interface = intf;
return 1;
}
return 0;
*/
struct usb_interface *usb_find_interface(struct usb_driver *drv, int minor)
{
- struct usb_interface *intf = (struct usb_interface *)(long)minor;
- int ret;
+ struct find_interface_arg argb;
- ret = driver_for_each_device(&drv->driver, NULL, &intf, __find_interface);
-
- return ret ? intf : NULL;
+ argb.minor = minor;
+ argb.interface = NULL;
+ driver_for_each_device(&drv->driver, NULL, &argb, __find_interface);
+ return argb.interface;
}
#ifdef CONFIG_HOTPLUG
/*
- * USB hotplugging invokes what /proc/sys/kernel/hotplug says
- * (normally /sbin/hotplug) when USB devices get added or removed.
- *
- * This invokes a user mode policy agent, typically helping to load driver
+ * This sends an uevent to userspace, typically helping to load driver
* or other modules, configure the device, and more. Drivers can provide
* a MODULE_DEVICE_TABLE to help with module loading subtasks.
*
* delays in event delivery. Use sysfs (and DEVPATH) to make sure the
* device (and this configuration!) are still present.
*/
-static int usb_hotplug (struct device *dev, char **envp, int num_envp,
- char *buffer, int buffer_size)
+static int usb_uevent(struct device *dev, char **envp, int num_envp,
+ char *buffer, int buffer_size)
{
struct usb_interface *intf;
struct usb_device *usb_dev;
return -ENODEV;
/* driver is often null here; dev_dbg() would oops */
- pr_debug ("usb %s: hotplug\n", dev->bus_id);
+ pr_debug ("usb %s: uevent\n", dev->bus_id);
/* Must check driver_data here, as on remove driver is always NULL */
if ((dev->driver == &usb_generic_driver) ||
*
* FIXME reduce hardwired intelligence here
*/
- if (add_hotplug_env_var(envp, num_envp, &i,
- buffer, buffer_size, &length,
- "DEVICE=/proc/bus/usb/%03d/%03d",
- usb_dev->bus->busnum, usb_dev->devnum))
+ if (add_uevent_var(envp, num_envp, &i,
+ buffer, buffer_size, &length,
+ "DEVICE=/proc/bus/usb/%03d/%03d",
+ usb_dev->bus->busnum, usb_dev->devnum))
return -ENOMEM;
#endif
/* per-device configurations are common */
- if (add_hotplug_env_var(envp, num_envp, &i,
- buffer, buffer_size, &length,
- "PRODUCT=%x/%x/%x",
- le16_to_cpu(usb_dev->descriptor.idVendor),
- le16_to_cpu(usb_dev->descriptor.idProduct),
- le16_to_cpu(usb_dev->descriptor.bcdDevice)))
+ if (add_uevent_var(envp, num_envp, &i,
+ buffer, buffer_size, &length,
+ "PRODUCT=%x/%x/%x",
+ le16_to_cpu(usb_dev->descriptor.idVendor),
+ le16_to_cpu(usb_dev->descriptor.idProduct),
+ le16_to_cpu(usb_dev->descriptor.bcdDevice)))
return -ENOMEM;
/* class-based driver binding models */
- if (add_hotplug_env_var(envp, num_envp, &i,
- buffer, buffer_size, &length,
- "TYPE=%d/%d/%d",
- usb_dev->descriptor.bDeviceClass,
- usb_dev->descriptor.bDeviceSubClass,
- usb_dev->descriptor.bDeviceProtocol))
+ if (add_uevent_var(envp, num_envp, &i,
+ buffer, buffer_size, &length,
+ "TYPE=%d/%d/%d",
+ usb_dev->descriptor.bDeviceClass,
+ usb_dev->descriptor.bDeviceSubClass,
+ usb_dev->descriptor.bDeviceProtocol))
return -ENOMEM;
- if (add_hotplug_env_var(envp, num_envp, &i,
- buffer, buffer_size, &length,
- "INTERFACE=%d/%d/%d",
- alt->desc.bInterfaceClass,
- alt->desc.bInterfaceSubClass,
- alt->desc.bInterfaceProtocol))
+ if (add_uevent_var(envp, num_envp, &i,
+ buffer, buffer_size, &length,
+ "INTERFACE=%d/%d/%d",
+ alt->desc.bInterfaceClass,
+ alt->desc.bInterfaceSubClass,
+ alt->desc.bInterfaceProtocol))
return -ENOMEM;
- if (add_hotplug_env_var(envp, num_envp, &i,
- buffer, buffer_size, &length,
- "MODALIAS=usb:v%04Xp%04Xd%04Xdc%02Xdsc%02Xdp%02Xic%02Xisc%02Xip%02X",
- le16_to_cpu(usb_dev->descriptor.idVendor),
- le16_to_cpu(usb_dev->descriptor.idProduct),
- le16_to_cpu(usb_dev->descriptor.bcdDevice),
- usb_dev->descriptor.bDeviceClass,
- usb_dev->descriptor.bDeviceSubClass,
- usb_dev->descriptor.bDeviceProtocol,
- alt->desc.bInterfaceClass,
- alt->desc.bInterfaceSubClass,
- alt->desc.bInterfaceProtocol))
+ if (add_uevent_var(envp, num_envp, &i,
+ buffer, buffer_size, &length,
+ "MODALIAS=usb:v%04Xp%04Xd%04Xdc%02Xdsc%02Xdp%02Xic%02Xisc%02Xip%02X",
+ le16_to_cpu(usb_dev->descriptor.idVendor),
+ le16_to_cpu(usb_dev->descriptor.idProduct),
+ le16_to_cpu(usb_dev->descriptor.bcdDevice),
+ usb_dev->descriptor.bDeviceClass,
+ usb_dev->descriptor.bDeviceSubClass,
+ usb_dev->descriptor.bDeviceProtocol,
+ alt->desc.bInterfaceClass,
+ alt->desc.bInterfaceSubClass,
+ alt->desc.bInterfaceProtocol))
return -ENOMEM;
envp[i] = NULL;
#else
-static int usb_hotplug (struct device *dev, char **envp,
+static int usb_uevent(struct device *dev, char **envp,
int num_envp, char *buffer, int buffer_size)
{
return -ENODEV;
/* hub driver sets up TT records */
}
+ dev->portnum = port1;
dev->bus = bus;
dev->parent = parent;
INIT_LIST_HEAD(&dev->filelist);
- init_MUTEX(&dev->serialize);
-
return dev;
}
/* USB device locking
*
- * Although locking USB devices should be straightforward, it is
- * complicated by the way the driver-model core works. When a new USB
- * driver is registered or unregistered, the core will automatically
- * probe or disconnect all matching interfaces on all USB devices while
- * holding the USB subsystem writelock. There's no good way for us to
- * tell which devices will be used or to lock them beforehand; our only
- * option is to effectively lock all the USB devices.
- *
- * We do that by using a private rw-semaphore, usb_all_devices_rwsem.
- * When locking an individual device you must first acquire the rwsem's
- * readlock. When a driver is registered or unregistered the writelock
- * must be held. These actions are encapsulated in the subroutines
- * below, so all a driver needs to do is call usb_lock_device() and
- * usb_unlock_device().
+ * 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 problem is that
- * usb_lock_device() must not be called to lock a second device since it
- * would acquire the rwsem's readlock reentrantly, leading to deadlock if
- * another thread was waiting for the writelock. The solution is simple:
- *
- * When locking more than one device, call usb_lock_device()
- * to lock the first one. Lock the others by calling
- * down(&udev->serialize) directly.
- *
- * When unlocking multiple devices, use up(&udev->serialize)
- * to unlock all but the last one. Unlock the last one by
- * calling usb_unlock_device().
+ * 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 - acquire the lock for a usb device structure
- * @udev: device that's being locked
- *
- * Use this routine when you don't hold any other device locks;
- * to acquire nested inner locks call down(&udev->serialize) directly.
- * This is necessary for proper interaction with usb_lock_all_devices().
- */
-void usb_lock_device(struct usb_device *udev)
-{
- down_read(&usb_all_devices_rwsem);
- down(&udev->serialize);
-}
-
-/**
- * usb_trylock_device - attempt to acquire the lock for a usb device structure
- * @udev: device that's being locked
- *
- * Don't use this routine if you already hold a device lock;
- * use down_trylock(&udev->serialize) instead.
- * This is necessary for proper interaction with usb_lock_all_devices().
- *
- * Returns 1 if successful, 0 if contention.
- */
-int usb_trylock_device(struct usb_device *udev)
-{
- if (!down_read_trylock(&usb_all_devices_rwsem))
- return 0;
- if (down_trylock(&udev->serialize)) {
- up_read(&usb_all_devices_rwsem);
- return 0;
- }
- return 1;
-}
-
/**
* usb_lock_device_for_reset - cautiously acquire the lock for a
* usb device structure
}
}
- while (!usb_trylock_device(udev)) {
+ while (usb_trylock_device(udev) != 0) {
/* If we can't acquire the lock after waiting one second,
* we're probably deadlocked */
return 1;
}
-/**
- * usb_unlock_device - release the lock for a usb device structure
- * @udev: device that's being unlocked
- *
- * Use this routine when releasing the only device lock you hold;
- * to release inner nested locks call up(&udev->serialize) directly.
- * This is necessary for proper interaction with usb_lock_all_devices().
- */
-void usb_unlock_device(struct usb_device *udev)
-{
- up(&udev->serialize);
- up_read(&usb_all_devices_rwsem);
-}
-
-/**
- * usb_lock_all_devices - acquire the lock for all usb device structures
- *
- * This is necessary when registering a new driver or probing a bus,
- * since the driver-model core may try to use any usb_device.
- */
-void usb_lock_all_devices(void)
-{
- down_write(&usb_all_devices_rwsem);
-}
-
-/**
- * usb_unlock_all_devices - release the lock for all usb device structures
- */
-void usb_unlock_all_devices(void)
-{
- up_write(&usb_all_devices_rwsem);
-}
-
static struct usb_device *match_device(struct usb_device *dev,
u16 vendor_id, u16 product_id)
/* look through all of the children of this device */
for (child = 0; child < dev->maxchild; ++child) {
if (dev->children[child]) {
- down(&dev->children[child]->serialize);
+ usb_lock_device(dev->children[child]);
ret_dev = match_device(dev->children[child],
vendor_id, product_id);
- up(&dev->children[child]->serialize);
+ usb_unlock_device(dev->children[child]);
if (ret_dev)
goto exit;
}
struct bus_type usb_bus_type = {
.name = "usb",
.match = usb_device_match,
- .hotplug = usb_hotplug,
+ .uevent = usb_uevent,
.suspend = usb_generic_suspend,
.resume = usb_generic_resume,
};
-#ifndef MODULE
-
-static int __init usb_setup_disable(char *str)
-{
- nousb = 1;
- return 1;
-}
-
/* format to disable USB on kernel command line is: nousb */
-__setup("nousb", usb_setup_disable);
-
-#endif
+__module_param_call("", nousb, param_set_bool, param_get_bool, &nousb, 0444);
/*
* for external read access to <nousb>
EXPORT_SYMBOL(usb_get_dev);
EXPORT_SYMBOL(usb_hub_tt_clear_buffer);
-EXPORT_SYMBOL(usb_lock_device);
-EXPORT_SYMBOL(usb_trylock_device);
EXPORT_SYMBOL(usb_lock_device_for_reset);
-EXPORT_SYMBOL(usb_unlock_device);
EXPORT_SYMBOL(usb_driver_claim_interface);
EXPORT_SYMBOL(usb_driver_release_interface);
projects / firefly-linux-kernel-4.4.55.git / blobdiff