diff options
Diffstat (limited to 'drivers/usb/core/driver.c')
| -rw-r--r-- | drivers/usb/core/driver.c | 419 |
1 files changed, 389 insertions, 30 deletions
diff --git a/drivers/usb/core/driver.c b/drivers/usb/core/driver.c index a5d11461f5a9cf..2b2000ac05ab5c 100644 --- a/drivers/usb/core/driver.c +++ b/drivers/usb/core/driver.c @@ -157,12 +157,13 @@ static int usb_probe_device(struct device *dev) udev = to_usb_device(dev); - /* FIXME: resume a suspended device */ - if (udev->state == USB_STATE_SUSPENDED) - return -EHOSTUNREACH; - /* TODO: Add real matching code */ + /* The device should always appear to be in use + * unless the driver suports autosuspend. + */ + udev->pm_usage_cnt = !(udriver->supports_autosuspend); + error = udriver->probe(udev); return error; } @@ -182,6 +183,7 @@ static int usb_probe_interface(struct device *dev) { struct usb_driver *driver = to_usb_driver(dev->driver); struct usb_interface *intf; + struct usb_device *udev; const struct usb_device_id *id; int error = -ENODEV; @@ -191,10 +193,7 @@ static int usb_probe_interface(struct device *dev) return error; intf = to_usb_interface(dev); - - /* FIXME we'd much prefer to just resume it ... */ - if (interface_to_usbdev(intf)->state == USB_STATE_SUSPENDED) - return -EHOSTUNREACH; + udev = interface_to_usbdev(intf); id = usb_match_id(intf, driver->id_table); if (!id) @@ -202,18 +201,31 @@ static int usb_probe_interface(struct device *dev) if (id) { dev_dbg(dev, "%s - got id\n", __FUNCTION__); + error = usb_autoresume_device(udev, 1); + if (error) + return error; + /* Interface "power state" doesn't correspond to any hardware * state whatsoever. We use it to record when it's bound to * a driver that may start I/0: it's not frozen/quiesced. */ mark_active(intf); intf->condition = USB_INTERFACE_BINDING; + + /* The interface should always appear to be in use + * unless the driver suports autosuspend. + */ + intf->pm_usage_cnt = !(driver->supports_autosuspend); + error = driver->probe(intf, id); if (error) { mark_quiesced(intf); + intf->needs_remote_wakeup = 0; intf->condition = USB_INTERFACE_UNBOUND; } else intf->condition = USB_INTERFACE_BOUND; + + usb_autosuspend_device(udev, 1); } return error; @@ -224,9 +236,15 @@ static int usb_unbind_interface(struct device *dev) { struct usb_driver *driver = to_usb_driver(dev->driver); struct usb_interface *intf = to_usb_interface(dev); + struct usb_device *udev; + int error; intf->condition = USB_INTERFACE_UNBINDING; + /* Autoresume for set_interface call below */ + udev = interface_to_usbdev(intf); + error = usb_autoresume_device(udev, 1); + /* release all urbs for this interface */ usb_disable_interface(interface_to_usbdev(intf), intf); @@ -237,8 +255,13 @@ static int usb_unbind_interface(struct device *dev) intf->altsetting[0].desc.bInterfaceNumber, 0); usb_set_intfdata(intf, NULL); + intf->condition = USB_INTERFACE_UNBOUND; mark_quiesced(intf); + intf->needs_remote_wakeup = 0; + + if (!error) + usb_autosuspend_device(udev, 1); return 0; } @@ -267,14 +290,19 @@ int usb_driver_claim_interface(struct usb_driver *driver, struct usb_interface *iface, void* priv) { struct device *dev = &iface->dev; + struct usb_device *udev = interface_to_usbdev(iface); if (dev->driver) return -EBUSY; dev->driver = &driver->drvwrap.driver; usb_set_intfdata(iface, priv); + + mutex_lock_nested(&udev->pm_mutex, udev->level); iface->condition = USB_INTERFACE_BOUND; mark_active(iface); + iface->pm_usage_cnt = !(driver->supports_autosuspend); + mutex_unlock(&udev->pm_mutex); /* if interface was already added, bind now; else let * the future device_add() bind it, bypassing probe() @@ -304,6 +332,7 @@ void usb_driver_release_interface(struct usb_driver *driver, struct usb_interface *iface) { struct device *dev = &iface->dev; + struct usb_device *udev = interface_to_usbdev(iface); /* this should never happen, don't release something that's not ours */ if (!dev->driver || dev->driver != &driver->drvwrap.driver) @@ -321,8 +350,12 @@ void usb_driver_release_interface(struct usb_driver *driver, dev->driver = NULL; usb_set_intfdata(iface, NULL); + + mutex_lock_nested(&udev->pm_mutex, udev->level); iface->condition = USB_INTERFACE_UNBOUND; mark_quiesced(iface); + iface->needs_remote_wakeup = 0; + mutex_unlock(&udev->pm_mutex); } EXPORT_SYMBOL(usb_driver_release_interface); @@ -751,7 +784,7 @@ EXPORT_SYMBOL_GPL_FUTURE(usb_deregister); #ifdef CONFIG_PM -/* Caller has locked udev */ +/* Caller has locked udev->pm_mutex */ static int suspend_device(struct usb_device *udev, pm_message_t msg) { struct usb_device_driver *udriver; @@ -763,6 +796,7 @@ static int suspend_device(struct usb_device *udev, pm_message_t msg) /* For devices that don't have a driver, we do a standard suspend. */ if (udev->dev.driver == NULL) { + udev->do_remote_wakeup = 0; status = usb_port_suspend(udev); goto done; } @@ -771,12 +805,13 @@ static int suspend_device(struct usb_device *udev, pm_message_t msg) status = udriver->suspend(udev, msg); done: + // dev_dbg(&udev->dev, "%s: status %d\n", __FUNCTION__, status); if (status == 0) udev->dev.power.power_state.event = msg.event; return status; } -/* Caller has locked udev */ +/* Caller has locked udev->pm_mutex */ static int resume_device(struct usb_device *udev) { struct usb_device_driver *udriver; @@ -796,12 +831,13 @@ static int resume_device(struct usb_device *udev) status = udriver->resume(udev); done: + // dev_dbg(&udev->dev, "%s: status %d\n", __FUNCTION__, status); if (status == 0) udev->dev.power.power_state.event = PM_EVENT_ON; return status; } -/* Caller has locked intf's usb_device */ +/* Caller has locked intf's usb_device's pm_mutex */ static int suspend_interface(struct usb_interface *intf, pm_message_t msg) { struct usb_driver *driver; @@ -812,31 +848,33 @@ static int suspend_interface(struct usb_interface *intf, pm_message_t msg) !is_active(intf)) goto done; - if (intf->dev.driver == NULL) /* This can't happen */ + if (intf->condition == USB_INTERFACE_UNBOUND) /* This can't happen */ goto done; driver = to_usb_driver(intf->dev.driver); if (driver->suspend && driver->resume) { status = driver->suspend(intf, msg); - if (status) + if (status == 0) + mark_quiesced(intf); + else if (!interface_to_usbdev(intf)->auto_pm) dev_err(&intf->dev, "%s error %d\n", "suspend", status); - else - mark_quiesced(intf); } else { // FIXME else if there's no suspend method, disconnect... + // Not possible if auto_pm is set... dev_warn(&intf->dev, "no suspend for driver %s?\n", driver->name); mark_quiesced(intf); } done: + // dev_dbg(&intf->dev, "%s: status %d\n", __FUNCTION__, status); if (status == 0) intf->dev.power.power_state.event = msg.event; return status; } -/* Caller has locked intf's usb_device */ +/* Caller has locked intf's usb_device's pm_mutex */ static int resume_interface(struct usb_interface *intf) { struct usb_driver *driver; @@ -846,8 +884,12 @@ static int resume_interface(struct usb_interface *intf) is_active(intf)) goto done; + /* Don't let autoresume interfere with unbinding */ + if (intf->condition == USB_INTERFACE_UNBINDING) + goto done; + /* Can't resume it if it doesn't have a driver. */ - if (intf->dev.driver == NULL) { + if (intf->condition == USB_INTERFACE_UNBOUND) { status = -ENOTCONN; goto done; } @@ -867,18 +909,88 @@ static int resume_interface(struct usb_interface *intf) } done: + // dev_dbg(&intf->dev, "%s: status %d\n", __FUNCTION__, status); if (status == 0) intf->dev.power.power_state.event = PM_EVENT_ON; return status; } -/* Caller has locked udev */ +/** + * usb_suspend_both - suspend a USB device and its interfaces + * @udev: the usb_device to suspend + * @msg: Power Management message describing this state transition + * + * This is the central routine for suspending USB devices. It calls the + * suspend methods for all the interface drivers in @udev and then calls + * the suspend method for @udev itself. If an error occurs at any stage, + * all the interfaces which were suspended are resumed so that they remain + * in the same state as the device. + * + * If an autosuspend is in progress (@udev->auto_pm is set), the routine + * checks first to make sure that neither the device itself or any of its + * active interfaces is in use (pm_usage_cnt is greater than 0). If they + * are, the autosuspend fails. + * + * If the suspend succeeds, the routine recursively queues an autosuspend + * request for @udev's parent device, thereby propagating the change up + * the device tree. If all of the parent's children are now suspended, + * the parent will autosuspend in turn. + * + * The suspend method calls are subject to mutual exclusion under control + * of @udev's pm_mutex. Many of these calls are also under the protection + * of @udev's device lock (including all requests originating outside the + * USB subsystem), but autosuspend requests generated by a child device or + * interface driver may not be. Usbcore will insure that the method calls + * do not arrive during bind, unbind, or reset operations. However, drivers + * must be prepared to handle suspend calls arriving at unpredictable times. + * The only way to block such calls is to do an autoresume (preventing + * autosuspends) while holding @udev's device lock (preventing outside + * suspends). + * + * The caller must hold @udev->pm_mutex. + * + * This routine can run only in process context. + */ int usb_suspend_both(struct usb_device *udev, pm_message_t msg) { int status = 0; int i = 0; struct usb_interface *intf; + struct usb_device *parent = udev->parent; + + cancel_delayed_work(&udev->autosuspend); + if (udev->state == USB_STATE_NOTATTACHED) + return 0; + if (udev->state == USB_STATE_SUSPENDED) + return 0; + udev->do_remote_wakeup = device_may_wakeup(&udev->dev); + + /* For autosuspend, fail fast if anything is in use. + * Also fail if any interfaces require remote wakeup but it + * isn't available. */ + if (udev->auto_pm) { + if (udev->pm_usage_cnt > 0) + return -EBUSY; + if (udev->actconfig) { + for (; i < udev->actconfig->desc.bNumInterfaces; i++) { + intf = udev->actconfig->interface[i]; + if (!is_active(intf)) + continue; + if (intf->pm_usage_cnt > 0) + return -EBUSY; + if (intf->needs_remote_wakeup && + !udev->do_remote_wakeup) { + dev_dbg(&udev->dev, + "remote wakeup needed for autosuspend\n"); + return -EOPNOTSUPP; + } + } + i = 0; + } + } + + /* Suspend all the interfaces and then udev itself */ if (udev->actconfig) { for (; i < udev->actconfig->desc.bNumInterfaces; i++) { intf = udev->actconfig->interface[i]; @@ -896,40 +1008,282 @@ int usb_suspend_both(struct usb_device *udev, pm_message_t msg) intf = udev->actconfig->interface[i]; resume_interface(intf); } - } + + /* If the suspend succeeded, propagate it up the tree */ + } else if (parent) + usb_autosuspend_device(parent, 0); + + // dev_dbg(&udev->dev, "%s: status %d\n", __FUNCTION__, status); return status; } -/* Caller has locked udev */ +/** + * usb_resume_both - resume a USB device and its interfaces + * @udev: the usb_device to resume + * + * This is the central routine for resuming USB devices. It calls the + * the resume method for @udev and then calls the resume methods for all + * the interface drivers in @udev. + * + * Before starting the resume, the routine calls itself recursively for + * the parent device of @udev, thereby propagating the change up the device + * tree and assuring that @udev will be able to resume. If the parent is + * unable to resume successfully, the routine fails. + * + * The resume method calls are subject to mutual exclusion under control + * of @udev's pm_mutex. Many of these calls are also under the protection + * of @udev's device lock (including all requests originating outside the + * USB subsystem), but autoresume requests generated by a child device or + * interface driver may not be. Usbcore will insure that the method calls + * do not arrive during bind, unbind, or reset operations. However, drivers + * must be prepared to handle resume calls arriving at unpredictable times. + * The only way to block such calls is to do an autoresume (preventing + * other autoresumes) while holding @udev's device lock (preventing outside + * resumes). + * + * The caller must hold @udev->pm_mutex. + * + * This routine can run only in process context. + */ int usb_resume_both(struct usb_device *udev) { - int status; + int status = 0; int i; struct usb_interface *intf; + struct usb_device *parent = udev->parent; + + cancel_delayed_work(&udev->autosuspend); + if (udev->state == USB_STATE_NOTATTACHED) + return -ENODEV; - /* Can't resume if the parent is suspended */ - if (udev->parent && udev->parent->state == USB_STATE_SUSPENDED) { - dev_warn(&udev->dev, "can't resume; parent is suspended\n"); - return -EHOSTUNREACH; + /* Propagate the resume up the tree, if necessary */ + if (udev->state == USB_STATE_SUSPENDED) { + if (parent) { + mutex_lock_nested(&parent->pm_mutex, parent->level); + parent->auto_pm = 1; + status = usb_resume_both(parent); + } else { + + /* We can't progagate beyond the USB subsystem, + * so if a root hub's controller is suspended + * then we're stuck. */ + if (udev->dev.parent->power.power_state.event != + PM_EVENT_ON) + status = -EHOSTUNREACH; + } + if (status == 0 && udev->state == USB_STATE_SUSPENDED) + status = resume_device(udev); + if (parent) + mutex_unlock(&parent->pm_mutex); } - status = resume_device(udev); + /* Now the parent won't suspend until we are finished */ + if (status == 0 && udev->actconfig) { for (i = 0; i < udev->actconfig->desc.bNumInterfaces; i++) { intf = udev->actconfig->interface[i]; resume_interface(intf); } } + + // dev_dbg(&udev->dev, "%s: status %d\n", __FUNCTION__, status); + return status; +} + +#ifdef CONFIG_USB_SUSPEND + +/** + * usb_autosuspend_device - delayed autosuspend of a USB device and its interfaces + * @udev - the usb_device to autosuspend + * @dec_usage_cnt - flag to decrement @udev's PM-usage counter + * + * This routine should be called when a core subsystem is finished using + * @udev and wants to allow it to autosuspend. Examples would be when + * @udev's device file in usbfs is closed or after a configuration change. + * + * @dec_usage_cnt should be 1 if the subsystem previously incremented + * @udev's usage counter (such as by passing 1 to usb_autoresume_device); + * otherwise it should be 0. + * + * If the usage counter for @udev or any of its active interfaces is greater + * than 0, the autosuspend request will not be queued. (If an interface + * driver does not support autosuspend then its usage counter is permanently + * positive.) Likewise, if an interface driver requires remote-wakeup + * capability during autosuspend but remote wakeup is disabled, the + * autosuspend will fail. + * + * Often the caller will hold @udev's device lock, but this is not + * necessary. + * + * This routine can run only in process context. + */ +void usb_autosuspend_device(struct usb_device *udev, int dec_usage_cnt) +{ + mutex_lock_nested(&udev->pm_mutex, udev->level); + udev->pm_usage_cnt -= dec_usage_cnt; + if (udev->pm_usage_cnt <= 0) + schedule_delayed_work(&udev->autosuspend, + USB_AUTOSUSPEND_DELAY); + mutex_unlock(&udev->pm_mutex); + // dev_dbg(&udev->dev, "%s: cnt %d\n", + // __FUNCTION__, udev->pm_usage_cnt); +} + +/** + * usb_autoresume_device - immediately autoresume a USB device and its interfaces + * @udev - the usb_device to autoresume + * @inc_usage_cnt - flag to increment @udev's PM-usage counter + * + * This routine should be called when a core subsystem wants to use @udev + * and needs to guarantee that it is not suspended. In addition, the + * caller can prevent @udev from being autosuspended subsequently. (Note + * that this will not prevent suspend events originating in the PM core.) + * Examples would be when @udev's device file in usbfs is opened (autosuspend + * should be prevented until the file is closed) or when a remote-wakeup + * request is received (later autosuspends should not be prevented). + * + * @inc_usage_cnt should be 1 to increment @udev's usage counter and prevent + * autosuspends. This prevention will persist until the usage counter is + * decremented again (such as by passing 1 to usb_autosuspend_device). + * Otherwise @inc_usage_cnt should be 0 to leave the usage counter unchanged. + * Regardless, if the autoresume fails then the usage counter is not + * incremented. + * + * Often the caller will hold @udev's device lock, but this is not + * necessary (and attempting it might cause deadlock). + * + * This routine can run only in process context. + */ +int usb_autoresume_device(struct usb_device *udev, int inc_usage_cnt) +{ + int status; + + mutex_lock_nested(&udev->pm_mutex, udev->level); + udev->pm_usage_cnt += inc_usage_cnt; + udev->auto_pm = 1; + status = usb_resume_both(udev); + if (status != 0) + udev->pm_usage_cnt -= inc_usage_cnt; + mutex_unlock(&udev->pm_mutex); + // dev_dbg(&udev->dev, "%s: status %d cnt %d\n", + // __FUNCTION__, status, udev->pm_usage_cnt); + return status; +} + +/** + * usb_autopm_put_interface - decrement a USB interface's PM-usage counter + * @intf - the usb_interface whose counter should be decremented + * + * This routine should be called by an interface driver when it is + * finished using @intf and wants to allow it to autosuspend. A typical + * example would be a character-device driver when its device file is + * closed. + * + * The routine decrements @intf's usage counter. When the counter reaches + * 0, a delayed autosuspend request for @intf's device is queued. When + * the delay expires, if @intf->pm_usage_cnt is still <= 0 along with all + * the other usage counters for the sibling interfaces and @intf's + * usb_device, the device and all its interfaces will be autosuspended. + * + * Note that @intf->pm_usage_cnt is owned by the interface driver. The + * core will not change its value other than the increment and decrement + * in usb_autopm_get_interface and usb_autopm_put_interface. The driver + * may use this simple counter-oriented discipline or may set the value + * any way it likes. + * + * If the driver has set @intf->needs_remote_wakeup then autosuspend will + * take place only if the device's remote-wakeup facility is enabled. + * + * Suspend method calls queued by this routine can arrive at any time + * while @intf is resumed and its usage counter is equal to 0. They are + * not protected by the usb_device's lock but only by its pm_mutex. + * Drivers must provide their own synchronization. + * + * This routine can run only in process context. + */ +void usb_autopm_put_interface(struct usb_interface *intf) +{ + struct usb_device *udev = interface_to_usbdev(intf); + + mutex_lock_nested(&udev->pm_mutex, udev->level); + if (intf->condition != USB_INTERFACE_UNBOUND) { + if (--intf->pm_usage_cnt <= 0) + schedule_delayed_work(&udev->autosuspend, + USB_AUTOSUSPEND_DELAY); + } + mutex_unlock(&udev->pm_mutex); + // dev_dbg(&intf->dev, "%s: cnt %d\n", + // __FUNCTION__, intf->pm_usage_cnt); +} +EXPORT_SYMBOL_GPL(usb_autopm_put_interface); + +/** + * usb_autopm_get_interface - increment a USB interface's PM-usage counter + * @intf - the usb_interface whose counter should be incremented + * + * This routine should be called by an interface driver when it wants to + * use @intf and needs to guarantee that it is not suspended. In addition, + * the routine prevents @intf from being autosuspended subsequently. (Note + * that this will not prevent suspend events originating in the PM core.) + * This prevention will persist until usb_autopm_put_interface() is called + * or @intf is unbound. A typical example would be a character-device + * driver when its device file is opened. + * + * The routine increments @intf's usage counter. So long as the counter + * is greater than 0, autosuspend will not be allowed for @intf or its + * usb_device. When the driver is finished using @intf it should call + * usb_autopm_put_interface() to decrement the usage counter and queue + * a delayed autosuspend request (if the counter is <= 0). + * + * Note that @intf->pm_usage_cnt is owned by the interface driver. The + * core will not change its value other than the increment and decrement + * in usb_autopm_get_interface and usb_autopm_put_interface. The driver + * may use this simple counter-oriented discipline or may set the value + * any way it likes. + * + * Resume method calls generated by this routine can arrive at any time + * while @intf is suspended. They are not protected by the usb_device's + * lock but only by its pm_mutex. Drivers must provide their own + * synchronization. + * + * This routine can run only in process context. + */ +int usb_autopm_get_interface(struct usb_interface *intf) +{ + struct usb_device *udev = interface_to_usbdev(intf); + int status; + + mutex_lock_nested(&udev->pm_mutex, udev->level); + if (intf->condition == USB_INTERFACE_UNBOUND) + status = -ENODEV; + else { + ++intf->pm_usage_cnt; + udev->auto_pm = 1; + status = usb_resume_both(udev); + if (status != 0) + --intf->pm_usage_cnt; + } + mutex_unlock(&udev->pm_mutex); + // dev_dbg(&intf->dev, "%s: status %d cnt %d\n", + // __FUNCTION__, status, intf->pm_usage_cnt); return status; } +EXPORT_SYMBOL_GPL(usb_autopm_get_interface); + +#endif /* CONFIG_USB_SUSPEND */ static int usb_suspend(struct device *dev, pm_message_t message) { int status; - if (is_usb_device(dev)) - status = usb_suspend_both(to_usb_device(dev), message); - else + if (is_usb_device(dev)) { + struct usb_device *udev = to_usb_device(dev); + + mutex_lock_nested(&udev->pm_mutex, udev->level); + udev->auto_pm = 0; + status = usb_suspend_both(udev, message); + mutex_unlock(&udev->pm_mutex); + } else status = 0; return status; } @@ -939,7 +1293,12 @@ static int usb_resume(struct device *dev) int status; if (is_usb_device(dev)) { - status = usb_resume_both(to_usb_device(dev)); + struct usb_device *udev = to_usb_device(dev); + + mutex_lock_nested(&udev->pm_mutex, udev->level); + udev->auto_pm = 0; + status = usb_resume_both(udev); + mutex_unlock(&udev->pm_mutex); /* Rebind drivers that had no suspend method? */ } else |