/**
* generic_probe:当插入usb设备时的通用驱动探测借口
* @ udev:
*/
static int generic_probe(struct usb_device *udev)
{
int err, c;
/* Choose and set the configuration. This registers the interfaces
* with the driver core and lets interface drivers bind to them.
*/
if (usb_device_is_owned(udev))
; /* Don't configure if the device is owned */
else if (udev->authorized == 0)
dev_err(&udev->dev, "Device is not authorized for usage\n");
else {
c = usb_choose_configuration(udev);
if (c >= 0) {
err = usb_set_configuration(udev, c);
if (err) {
dev_err(&udev->dev, "can't set config #%d, error %d\n",
c, err);
/* This need not be fatal. The user can try to
* set other configurations. */
}
}
}
/* USB device state == configured ... usable */
usb_notify_add_device(udev);
return 0;
}
int usb_choose_configuration(struct usb_device *udev)
{
int i;
int num_configs;
int insufficient_power = 0;
struct usb_host_config *c, *best;
if (usb_device_is_owned(udev))
return 0;
best = NULL;
c = udev->config;
num_configs = udev->descriptor.bNumConfigurations;
for (i = 0; i < num_configs; (i++, c++)) {
struct usb_interface_descriptor *desc = NULL;
/* It's possible that a config has no interfaces! */
if (c->desc.bNumInterfaces > 0)
desc = &c->intf_cache[0]->altsetting->desc;
/*
* HP's USB bus-powered keyboard has only one configuration
* and it claims to be self-powered; other devices may have
* similar errors in their descriptors. If the next test
* were allowed to execute, such configurations would always
* be rejected and the devices would not work as expected.
* In the meantime, we run the risk of selecting a config
* that requires external power at a time when that power
* isn't available. It seems to be the lesser of two evils.
*
* Bugzilla #6448 reports a device that appears to crash
* when it receives a GET_DEVICE_STATUS request! We don't
* have any other way to tell whether a device is self-powered,
* but since we don't use that information anywhere but here,
* the call has been removed.
*
* Maybe the GET_DEVICE_STATUS call and the test below can
* be reinstated when device firmwares become more reliable.
* Don't hold your breath.
*/
#if 0
/* Rule out self-powered configs for a bus-powered device */
if (bus_powered && (c->desc.bmAttributes &
USB_CONFIG_ATT_SELFPOWER))
continue;
#endif
/*
* The next test may not be as effective as it should be.
* Some hubs have errors in their descriptor, claiming
* to be self-powered when they are really bus-powered.
* We will overestimate the amount of current such hubs
* make available for each port.
*
* This is a fairly benign sort of failure. It won't
* cause us to reject configurations that we should have
* accepted.
*/
/* Rule out configs that draw too much bus current */
if (usb_get_max_power(udev, c) > udev->bus_mA) {
insufficient_power++;
MYDBG("insufficient available bus power to %d intf, the intf class is 0x%x \n", desc->bInterfaceNumber , desc->bInterfaceClass);
continue;
}
/* When the first config's first interface is one of Microsoft's
* pet nonstandard Ethernet-over-USB protocols, ignore it unless
* this kernel has enabled the necessary host side driver.
* But: Don't ignore it if it's the only config.
*/
if (i == 0 && num_configs > 1 && desc &&
(is_rndis(desc) || is_activesync(desc))) {
#if !defined(CONFIG_USB_NET_RNDIS_HOST) && !defined(CONFIG_USB_NET_RNDIS_HOST_MODULE)
continue;
#else
best = c;
#endif
}
/* From the remaining configs, choose the first one whose
* first interface is for a non-vendor-specific class.
* Reason: Linux is more likely to have a class driver
* than a vendor-specific driver. */
else if (udev->descriptor.bDeviceClass !=
USB_CLASS_VENDOR_SPEC &&
(desc && desc->bInterfaceClass !=
USB_CLASS_VENDOR_SPEC)) {
best = c;
break;
}
/* If all the remaining configs are vendor-specific,
* choose the first one. */
else if (!best)
best = c;
}
if (insufficient_power > 0)
dev_info(&udev->dev, "rejected %d configuration%s "
"due to insufficient available bus power\n",
insufficient_power, plural(insufficient_power));
if (best) {
i = best->desc.bConfigurationValue;
dev_dbg(&udev->dev,
"configuration #%d chosen from %d choice%s\n",
i, num_configs, plural(num_configs));
} else {
i = -1;
dev_warn(&udev->dev,
"no configuration chosen from %d choice%s\n",
num_configs, plural(num_configs));
#ifdef CONFIG_USBIF_COMPLIANCE
if ((insufficient_power>0) && (insufficient_power==num_configs)){
MYDBG("insufficient available bus power to all intf\n");
usbif_u3h_send_event("DEV_OVER_CURRENT");
}
#endif
}
return i;
}