LXR linux/include/linux/usb/ch9.h

   1/* SPDX-License-Identifier: GPL-2.0 */
   2/*
   3 * This file holds USB constants and structures that are needed for
   4 * USB device APIs.  These are used by the USB device model, which is
   5 * defined in chapter 9 of the USB 2.0 specification and in the
   6 * Wireless USB 1.0 (spread around).  Linux has several APIs in C that
   7 * need these:
   8 *
   9 * - the host side Linux-USB kernel driver API;
  10 * - the "usbfs" user space API; and
  11 * - the Linux "gadget" device/peripheral side driver API.
  12 *
  13 * USB 2.0 adds an additional "On The Go" (OTG) mode, which lets systems
  14 * act either as a USB host or as a USB device.  That means the host and
  15 * device side APIs benefit from working well together.
  16 *
  17 * There's also "Wireless USB", using low power short range radios for
  18 * peripheral interconnection but otherwise building on the USB framework.
  19 *
  20 * Note all descriptors are declared '__attribute__((packed))' so that:
  21 *
  22 * [a] they never get padded, either internally (USB spec writers
  23 *     probably handled that) or externally;
  24 *
  25 * [b] so that accessing bigger-than-a-bytes fields will never
  26 *     generate bus errors on any platform, even when the location of
  27 *     its descriptor inside a bundle isn't "naturally aligned", and
  28 *
  29 * [c] for consistency, removing all doubt even when it appears to
  30 *     someone that the two other points are non-issues for that
  31 *     particular descriptor type.
  32 */
  33#ifndef __LINUX_USB_CH9_H
  34#define __LINUX_USB_CH9_H
  35
  36#include <linux/device.h>
  37#include <uapi/linux/usb/ch9.h>
  38
  39/* USB 3.2 SuperSpeed Plus phy signaling rate generation and lane count */
  40
  41enum usb_ssp_rate {
  42        USB_SSP_GEN_UNKNOWN = 0,
  43        USB_SSP_GEN_2x1,
  44        USB_SSP_GEN_1x2,
  45        USB_SSP_GEN_2x2,
  46};
  47
  48extern const char *usb_ep_type_string(int ep_type);
  49extern const char *usb_speed_string(enum usb_device_speed speed);
  50extern enum usb_device_speed usb_get_maximum_speed(struct device *dev);
  51extern enum usb_ssp_rate usb_get_maximum_ssp_rate(struct device *dev);
  52extern const char *usb_state_string(enum usb_device_state state);
  53unsigned int usb_decode_interval(const struct usb_endpoint_descriptor *epd,
  54                                 enum usb_device_speed speed);
  55
  56#ifdef CONFIG_TRACING
  57extern const char *usb_decode_ctrl(char *str, size_t size, __u8 bRequestType,
  58                                   __u8 bRequest, __u16 wValue, __u16 wIndex,
  59                                   __u16 wLength);
  60#endif
  61
  62#endif /* __LINUX_USB_CH9_H */
  63