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STRUCT USB_COMPOSITE(9) Kernel Mode Gadget API STRUCT USB_COMPOSITE(9)

NAME

struct_usb_composite_dev - represents one composite usb gadget

SYNOPSIS

struct usb_composite_dev {
  struct usb_gadget * gadget;
  struct usb_request * req;
  struct usb_request * os_desc_req;
  struct usb_configuration * config;
  u8 qw_sign[OS_STRING_QW_SIGN_LEN];
  u8 b_vendor_code;
  struct usb_configuration * os_desc_config;
  unsigned int use_os_string:1;
};

MEMBERS

gadget
read-only, abstracts the gadget's usb peripheral controller
req
used for control responses; buffer is pre-allocated
os_desc_req
used for OS descriptors responses; buffer is pre-allocated
config
the currently active configuration
qw_sign[OS_STRING_QW_SIGN_LEN]
qwSignature part of the OS string
b_vendor_code
bMS_VendorCode part of the OS string
os_desc_config
the configuration to be used with OS descriptors
use_os_string
false by default, interested gadgets set it

DESCRIPTION

One of these devices is allocated and initialized before the associated device driver's bind is called.
OPEN ISSUE: it appears that some WUSB devices will need to be built by combining a normal (wired) gadget with a wireless one. This revision of the gadget framework should probably try to make sure doing that won't hurt too much.
One notion for how to handle Wireless USB devices involves: (a) a second gadget here, discovery mechanism TBD, but likely needing separate “register/unregister WUSB gadget” calls; (b) updates to usb_gadget to include flags “is it wireless”, “is it wired”, plus (presumably in a wrapper structure) bandgroup and PHY info; (c) presumably a wireless_ep wrapping a usb_ep, and reporting wireless-specific parameters like maxburst and maxsequence; (d) configurations that are specific to wireless links; (e) function drivers that understand wireless configs and will support wireless for (additional) function instances; (f) a function to support association setup (like CBAF), not necessarily requiring a wireless adapter; (g) composite device setup that can create one or more wireless configs, including appropriate association setup support; (h) more, TBD.

AUTHOR

David Brownell <dbrownell@users.sourceforge.net>
Author.

COPYRIGHT

January 2017 Kernel Hackers Manual 4.8.