static int usb_generic_suspend(struct device *dev, pm_message_t message)
{
struct usb_interface *intf;
struct usb_driver *driver;
int status;
/* USB devices enter SUSPEND state through their hubs, but can be
* marked for FREEZE as soon as their children are already idled.
* But those semantics are useless, so we equate the two (sigh).
*/
/*挂起usb设备*/
if (dev->driver == &usb_generic_driver) {
if (dev->power.power_state.event == message.event)
return 0;
/* we need to rule out bogus requests through sysfs */
status = device_for_each_child(dev, NULL, verify_suspended);
if (status)
return status;
/*挂起设备的操作*/
return usb_suspend_device (to_usb_device(dev));
}
if ((dev->driver == NULL) ||
(dev->driver_data == &usb_generic_driver_data))
return 0;
intf = to_usb_interface(dev);
driver = to_usb_driver(dev->driver);
/* with no hardware, USB interfaces only use FREEZE and ON states */
if (!is_active(intf))
return 0;
//挂起usb设备接口驱动
if (driver->suspend && driver->resume) {
status = driver->suspend(intf, message);
if (status)
dev_err(dev, "%s error %d\n", "suspend", status);
else
mark_quiesced(intf);
} else {
// FIXME else if there's no suspend method, disconnect...
dev_warn(dev, "no suspend for driver %s?\n", driver->name);
mark_quiesced(intf);
status = 0;
}
return status;
}
static int usb_generic_resume(struct device *dev)
{
struct usb_interface *intf;
struct usb_driver *driver;
struct usb_device *udev;
int status;
if (dev->power.power_state.event == PM_EVENT_ON)
return 0;
/* mark things as "on" immediately, no matter what errors crop up */
dev->power.power_state.event = PM_EVENT_ON;
/*唤醒usb设备*/
/* devices resume through their hubs */
if (dev->driver == &usb_generic_driver) {
udev = to_usb_device(dev);
if (udev->state == USB_STATE_NOTATTACHED)
return 0;
return usb_resume_device (to_usb_device(dev));
}
if ((dev->driver == NULL) ||
(dev->driver_data == &usb_generic_driver_data)) {
dev->power.power_state.event = PM_EVENT_FREEZE;
return 0;
}
intf = to_usb_interface(dev);
driver = to_usb_driver(dev->driver);
udev = interface_to_usbdev(intf);
if (udev->state == USB_STATE_NOTATTACHED)
return 0;
/* if driver was suspended, it has a resume method;
* however, sysfs can wrongly mark things as suspended
* (on the "no suspend method" FIXME path above)
*/
//唤醒usb设备接口的驱动
if (driver->resume) {
status = driver->resume(intf);
if (status) {
dev_err(dev, "%s error %d\n", "resume", status);
mark_quiesced(intf);
}
} else
dev_warn(dev, "no resume for driver %s?\n", driver->name);
return 0;
}
/**
* usb_driver_release_interface - unbind a driver from an interface
* @driver: the driver to be unbound
* @iface: the interface from which it will be unbound
*
* This can be used by drivers to release an interface without waiting
* for their disconnect() methods to be called. In typical cases this
* also causes the driver disconnect() method to be called.
*
* This call is synchronous, and may not be used in an interrupt context.
* Callers must own the device lock and the driver model's usb_bus_type.subsys
* writelock. So driver disconnect() entries don't need extra locking,
* but other call contexts may need to explicitly claim those locks.
*/
void usb_driver_release_interface(struct usb_driver *driver,
struct usb_interface *iface)
{
struct device *dev = &iface->dev;
/* this should never happen, don't release something that's not ours */
if (!dev->driver || dev->driver != &driver->driver)
return;
/* don't release from within disconnect() */
if (iface->condition != USB_INTERFACE_BOUND)
return;
/* don't release if the interface hasn't been added yet */
if (device_is_registered(dev)) {
iface->condition = USB_INTERFACE_UNBINDING;
device_release_driver(dev);
}
dev->driver = NULL;
usb_set_intfdata(iface, NULL);
iface->condition = USB_INTERFACE_UNBOUND;
mark_quiesced(iface);
}
/*
* usb_set_configuration - Makes a particular device setting be current
* @dev: the device whose configuration is being updated
* @configuration: the configuration being chosen.
* Context: !in_interrupt(), caller owns the device lock
*
* This is used to enable non-default device modes. Not all devices
* use this kind of configurability; many devices only have one
* configuration.
*
* @configuration is the value of the configuration to be installed.
* According to the USB spec (e.g. section 9.1.1.5), configuration values
* must be non-zero; a value of zero indicates that the device in
* unconfigured. However some devices erroneously use 0 as one of their
* configuration values. To help manage such devices, this routine will
* accept @configuration = -1 as indicating the device should be put in
* an unconfigured state.
*
* USB device configurations may affect Linux interoperability,
* power consumption and the functionality available. For example,
* the default configuration is limited to using 100mA of bus power,
* so that when certain device functionality requires more power,
* and the device is bus powered, that functionality should be in some
* non-default device configuration. Other device modes may also be
* reflected as configuration options, such as whether two ISDN
* channels are available independently; and choosing between open
* standard device protocols (like CDC) or proprietary ones.
*
* Note that USB has an additional level of device configurability,
* associated with interfaces. That configurability is accessed using
* usb_set_interface().
*
* This call is synchronous. The calling context must be able to sleep,
* must own the device lock, and must not hold the driver model's USB
* bus rwsem; usb device driver probe() methods cannot use this routine.
*
* Returns zero on success, or else the status code returned by the
* underlying call that failed. On successful completion, each interface
* in the original device configuration has been destroyed, and each one
* in the new configuration has been probed by all relevant usb device
* drivers currently known to the kernel.
*/
int usb_set_configuration(struct usb_device *dev, int configuration)
{
int i, ret;
struct usb_host_config *cp = NULL;
struct usb_interface **new_interfaces = NULL;
int n, nintf;
if (configuration == -1)
configuration = 0;
else {
for (i = 0; i < dev->descriptor.bNumConfigurations; i++) {
if (dev->config[i].desc.bConfigurationValue ==
configuration) {
cp = &dev->config[i];
break;
}
}
}
if ((!cp && configuration != 0))
return -EINVAL;
/* The USB spec says configuration 0 means unconfigured.
* But if a device includes a configuration numbered 0,
* we will accept it as a correctly configured state.
* Use -1 if you really want to unconfigure the device.
*/
if (cp && configuration == 0)
dev_warn(&dev->dev, "config 0 descriptor??\n");
/* Allocate memory for new interfaces before doing anything else,
* so that if we run out then nothing will have changed. */
n = nintf = 0;
if (cp) {
nintf = cp->desc.bNumInterfaces;
new_interfaces = kmalloc(nintf * sizeof(*new_interfaces),
GFP_KERNEL);
if (!new_interfaces) {
dev_err(&dev->dev, "Out of memory");
return -ENOMEM;
}
for (; n < nintf; ++n) {
new_interfaces[n] = kzalloc(
sizeof(struct usb_interface),
GFP_KERNEL);
if (!new_interfaces[n]) {
dev_err(&dev->dev, "Out of memory");
ret = -ENOMEM;
free_interfaces:
while (--n >= 0)
kfree(new_interfaces[n]);
kfree(new_interfaces);
return ret;
}
}
i = dev->bus_mA - cp->desc.bMaxPower * 2;
if (i < 0)
dev_warn(&dev->dev, "new config #%d exceeds power "
"limit by %dmA\n",
configuration, -i);
}
/* Wake up the device so we can send it the Set-Config request */
ret = usb_autoresume_device(dev);
if (ret)
goto free_interfaces;
/* if it's already configured, clear out old state first.
* getting rid of old interfaces means unbinding their drivers.
*/
if (dev->state != USB_STATE_ADDRESS)
usb_disable_device (dev, 1); // Skip ep0
if ((ret = usb_control_msg(dev, usb_sndctrlpipe(dev, 0),
USB_REQ_SET_CONFIGURATION, 0, configuration, 0,
NULL, 0, USB_CTRL_SET_TIMEOUT)) < 0) {
/* All the old state is gone, so what else can we do?
* The device is probably useless now anyway.
*/
cp = NULL;
}
dev->actconfig = cp;
if (!cp) {
usb_set_device_state(dev, USB_STATE_ADDRESS);
usb_autosuspend_device(dev);
goto free_interfaces;
}
usb_set_device_state(dev, USB_STATE_CONFIGURED);
/* Initialize the new interface structures and the
* hc/hcd/usbcore interface/endpoint state.
*/
for (i = 0; i < nintf; ++i) {
struct usb_interface_cache *intfc;
struct usb_interface *intf;
struct usb_host_interface *alt;
cp->interface[i] = intf = new_interfaces[i];
intfc = cp->intf_cache[i];
intf->altsetting = intfc->altsetting;
intf->num_altsetting = intfc->num_altsetting;
kref_get(&intfc->ref);
alt = usb_altnum_to_altsetting(intf, 0);
/* No altsetting 0? We'll assume the first altsetting.
* We could use a GetInterface call, but if a device is
* so non-compliant that it doesn't have altsetting 0
* then I wouldn't trust its reply anyway.
*/
if (!alt)
alt = &intf->altsetting[0];
intf->cur_altsetting = alt;
usb_enable_interface(dev, intf);
intf->dev.parent = &dev->dev;
intf->dev.driver = NULL;
intf->dev.bus = &usb_bus_type;
intf->dev.dma_mask = dev->dev.dma_mask;
intf->dev.release = release_interface;
device_initialize (&intf->dev);
mark_quiesced(intf);
sprintf (&intf->dev.bus_id[0], "%d-%s:%d.%d",
dev->bus->busnum, dev->devpath,
configuration, alt->desc.bInterfaceNumber);
}
kfree(new_interfaces);
if (cp->string == NULL)
cp->string = usb_cache_string(dev, cp->desc.iConfiguration);
/* Now that all the interfaces are set up, register them
* to trigger binding of drivers to interfaces. probe()
* routines may install different altsettings and may
* claim() any interfaces not yet bound. Many class drivers
* need that: CDC, audio, video, etc.
*/
for (i = 0; i < nintf; ++i) {
struct usb_interface *intf = cp->interface[i];
dev_dbg (&dev->dev,
"adding %s (config #%d, interface %d)\n",
intf->dev.bus_id, configuration,
intf->cur_altsetting->desc.bInterfaceNumber);
ret = device_add (&intf->dev);
if (ret != 0) {
dev_err(&dev->dev, "device_add(%s) --> %d\n",
intf->dev.bus_id, ret);
continue;
}
usb_create_sysfs_intf_files (intf);
}
usb_autosuspend_device(dev);
return 0;
}
/**ltl
功能:设置usb设备的配置，并且加载与接口相关的驱动程序
参数:dev ->usb设备
configuration ->usb配置编号
返回值:
说明:调用这个接口,usb设备才会进入配置阶段
*/
int usb_set_configuration(struct usb_device *dev, int configuration)
{
int i, ret;
struct usb_host_config *cp = NULL;
struct usb_interface **new_interfaces = NULL;
int n, nintf;
for (i = 0; i < dev->descriptor.bNumConfigurations; i++) {
if (dev->config[i].desc.bConfigurationValue == configuration) {
cp = &dev->config[i];
break;
}
}
if ((!cp && configuration != 0))
return -EINVAL;
/* The USB spec says configuration 0 means unconfigured.
* But if a device includes a configuration numbered 0,
* we will accept it as a correctly configured state.
*/
if (cp && configuration == 0)
dev_warn(&dev->dev, "config 0 descriptor??\n");
if (dev->state == USB_STATE_SUSPENDED)
return -EHOSTUNREACH;
/* Allocate memory for new interfaces before doing anything else,
* so that if we run out then nothing will have changed. */
n = nintf = 0;
if (cp) {
nintf = cp->desc.bNumInterfaces;//接口数量
new_interfaces = kmalloc(nintf * sizeof(*new_interfaces),
GFP_KERNEL);
if (!new_interfaces) {
dev_err(&dev->dev, "Out of memory");
return -ENOMEM;
}
for (; n < nintf; ++n) {
new_interfaces[n] = kzalloc(
sizeof(struct usb_interface),
GFP_KERNEL);
if (!new_interfaces[n]) {
dev_err(&dev->dev, "Out of memory");
ret = -ENOMEM;
free_interfaces:
while (--n >= 0)
kfree(new_interfaces[n]);
kfree(new_interfaces);
return ret;
}
}
i = dev->bus_mA - cp->desc.bMaxPower * 2;
if (i < 0)
dev_warn(&dev->dev, "new config #%d exceeds power "
"limit by %dmA\n",
configuration, -i);
}
/* if it's already configured, clear out old state first.
* getting rid of old interfaces means unbinding their drivers.
*/
if (dev->state != USB_STATE_ADDRESS)
usb_disable_device (dev, 1); // Skip ep0
//设置配置编号
if ((ret = usb_control_msg(dev, usb_sndctrlpipe(dev, 0),
USB_REQ_SET_CONFIGURATION, 0, configuration, 0,
NULL, 0, USB_CTRL_SET_TIMEOUT)) < 0) {
/* All the old state is gone, so what else can we do?
* The device is probably useless now anyway.
*/
cp = NULL;
}
//当前的配置对象
dev->actconfig = cp;
if (!cp) {
usb_set_device_state(dev, USB_STATE_ADDRESS);
goto free_interfaces;
}
usb_set_device_state(dev, USB_STATE_CONFIGURED);
/* Initialize the new interface structures and the
* hc/hcd/usbcore interface/endpoint state.
*/
//对interface对象赋值
for (i = 0; i < nintf; ++i) {
struct usb_interface_cache *intfc;
struct usb_interface *intf;
struct usb_host_interface *alt;
cp->interface[i] = intf = new_interfaces[i];
intfc = cp->intf_cache[i];
intf->altsetting = intfc->altsetting;
intf->num_altsetting = intfc->num_altsetting;
kref_get(&intfc->ref);
alt = usb_altnum_to_altsetting(intf, 0);
/* No altsetting 0? We'll assume the first altsetting.
* We could use a GetInterface call, but if a device is
* so non-compliant that it doesn't have altsetting 0
* then I wouldn't trust its reply anyway.
*/
if (!alt)
alt = &intf->altsetting[0];
intf->cur_altsetting = alt;
usb_enable_interface(dev, intf);
intf->dev.parent = &dev->dev;
intf->dev.driver = NULL;
/*总线驱动模型中，interface作为设备，如果interface是一个usb hub(bInterfaceClass=9)，则按总线驱动模型，就会匹配hub_driver驱动，调用device_add后，
最后调用hub_probe,去 分配usb_hub对象，并为每个hub关联中断处理函数，当hub端口中有设备插入时，hub产生
一中断hub_irq,最终唤醒线程hub_thread,然后为usb设备分配设备号(hub_port_connect_change)
;如果interface是一个usb设备(bInterfaceClass=x)，比如:usbmouse,此时会去匹配usb_mouse_driver。
*/
intf->dev.bus = &usb_bus_type;
intf->dev.dma_mask = dev->dev.dma_mask;
intf->dev.release = release_interface;
device_initialize (&intf->dev);
mark_quiesced(intf);
sprintf (&intf->dev.bus_id[0], "%d-%s:%d.%d",
dev->bus->busnum, dev->devpath,
configuration, alt->desc.bInterfaceNumber);
}
kfree(new_interfaces);
if (cp->string == NULL)
cp->string = usb_cache_string(dev, cp->desc.iConfiguration);
/* Now that all the interfaces are set up, register them
* to trigger binding of drivers to interfaces. probe()
* routines may install different altsettings and may
* claim() any interfaces not yet bound. Many class drivers
* need that: CDC, audio, video, etc.
*/
/*每个接口代表一个功能，每个接口都有一个驱动程序，载之*/
for (i = 0; i < nintf; ++i) {
struct usb_interface *intf = cp->interface[i];
dev_dbg (&dev->dev,
"adding %s (config #%d, interface %d)\n",
intf->dev.bus_id, configuration,
intf->cur_altsetting->desc.bInterfaceNumber);
//执行后，设备驱动将执行探针接口:hub_probe,storage_probe
ret = device_add (&intf->dev);
if (ret != 0) {
dev_err(&dev->dev, "device_add(%s) --> %d\n",
intf->dev.bus_id, ret);
continue;
}
usb_create_sysfs_intf_files (intf);
}
return 0;
}
