diff options
Diffstat (limited to 'include/linux/usb/ch9.h')
| -rw-r--r-- | include/linux/usb/ch9.h | 27 |
1 files changed, 27 insertions, 0 deletions
diff --git a/include/linux/usb/ch9.h b/include/linux/usb/ch9.h index da82606be605..58b83066bea4 100644 --- a/include/linux/usb/ch9.h +++ b/include/linux/usb/ch9.h @@ -70,4 +70,31 @@ extern enum usb_device_speed usb_get_maximum_speed(struct device *dev); */ extern const char *usb_state_string(enum usb_device_state state); +#ifdef CONFIG_TRACING +/** + * usb_decode_ctrl - Returns human readable representation of control request. + * @str: buffer to return a human-readable representation of control request. + * This buffer should have about 200 bytes. + * @size: size of str buffer. + * @bRequestType: matches the USB bmRequestType field + * @bRequest: matches the USB bRequest field + * @wValue: matches the USB wValue field (CPU byte order) + * @wIndex: matches the USB wIndex field (CPU byte order) + * @wLength: matches the USB wLength field (CPU byte order) + * + * Function returns decoded, formatted and human-readable description of + * control request packet. + * + * The usage scenario for this is for tracepoints, so function as a return + * use the same value as in parameters. This approach allows to use this + * function in TP_printk + * + * Important: wValue, wIndex, wLength parameters before invoking this function + * should be processed by le16_to_cpu macro. + */ +extern const char *usb_decode_ctrl(char *str, size_t size, __u8 bRequestType, + __u8 bRequest, __u16 wValue, __u16 wIndex, + __u16 wLength); +#endif + #endif /* __LINUX_USB_CH9_H */ |