usb gadget: composite gadget core
Add <linux/usb/composite.h> interfaces for composite gadget drivers, and
basic implementation support behind it:
- struct usb_function ... groups one or more interfaces into a function
managed as one unit within a configuration, to which it's added by
usb_add_function().
- struct usb_configuration ... groups one or more such functions into
a configuration managed as one unit by a driver, to which it's added
by usb_add_config(). These operate at either high or full/low speeds
and at a given bMaxPower.
- struct usb_composite_driver ... groups one or more such configurations
into a gadget driver, which may be registered or unregistered.
- struct usb_composite_dev ... a usb_composite_driver manages this; it
wraps the usb_gadget exposed by the controller driver.
This also includes some basic kerneldoc.
How to use it (the short version): provide a usb_composite_driver with a
bind() that calls usb_add_config() for each of the needed configurations.
The configurations in turn have bind() calls, which will usb_add_function()
for each function required. Each function's bind() allocates resources
needed to perform its tasks, like endpoints; sometimes configurations will
allocate resources too.
Separate patches will convert most gadget drivers to this infrastructure.
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This commit is contained in:
David Brownell
Greg Kroah-Hartman
parent
a4c39c41bf
commit
40982be52d
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@ -524,6 +524,41 @@ These utilities include endpoint autoconfiguration.
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<!-- !Edrivers/usb/gadget/epautoconf.c -->
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</sect1>
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<sect1 id="composite"><title>Composite Device Framework</title>
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<para>The core API is sufficient for writing drivers for composite
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USB devices (with more than one function in a given configuration),
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and also multi-configuration devices (also more than one function,
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but not necessarily sharing a given configuration).
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There is however an optional framework which makes it easier to
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reuse and combine functions.
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</para>
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<para>Devices using this framework provide a <emphasis>struct
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usb_composite_driver</emphasis>, which in turn provides one or
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more <emphasis>struct usb_configuration</emphasis> instances.
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Each such configuration includes at least one
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<emphasis>struct usb_function</emphasis>, which packages a user
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visible role such as "network link" or "mass storage device".
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Management functions may also exist, such as "Device Firmware
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Upgrade".
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</para>
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!Iinclude/linux/usb/composite.h
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!Edrivers/usb/gadget/composite.c
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</sect1>
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<sect1 id="functions"><title>Composite Device Functions</title>
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<para>At this writing, a few of the current gadget drivers have
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been converted to this framework.
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Near-term plans include converting all of them, except for "gadgetfs".
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</para>
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</sect1>
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</chapter>
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<chapter id="controllers"><title>Peripheral Controller Drivers</title>
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File diff suppressed because it is too large
Load Diff
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@ -0,0 +1,338 @@
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/*
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* composite.h -- framework for usb gadgets which are composite devices
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*
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* Copyright (C) 2006-2008 David Brownell
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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#ifndef __LINUX_USB_COMPOSITE_H
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#define __LINUX_USB_COMPOSITE_H
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/*
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* This framework is an optional layer on top of the USB Gadget interface,
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* making it easier to build (a) Composite devices, supporting multiple
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* functions within any single configuration, and (b) Multi-configuration
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* devices, also supporting multiple functions but without necessarily
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* having more than one function per configuration.
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*
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* Example: a device with a single configuration supporting both network
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* link and mass storage functions is a composite device. Those functions
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* might alternatively be packaged in individual configurations, but in
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* the composite model the host can use both functions at the same time.
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*/
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#include <linux/usb/ch9.h>
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#include <linux/usb/gadget.h>
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struct usb_configuration;
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/**
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* struct usb_function - describes one function of a configuration
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* @name: For diagnostics, identifies the function.
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* @strings: tables of strings, keyed by identifiers assigned during bind()
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* and by language IDs provided in control requests
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* @descriptors: Table of full (or low) speed descriptors, using interface and
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* string identifiers assigned during @bind(). If this pointer is null,
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* the function will not be available at full speed (or at low speed).
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* @hs_descriptors: Table of high speed descriptors, using interface and
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* string identifiers assigned during @bind(). If this pointer is null,
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* the function will not be available at high speed.
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* @config: assigned when @usb_add_function() is called; this is the
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* configuration with which this function is associated.
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* @bind: Before the gadget can register, all of its functions bind() to the
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* available resources including string and interface identifiers used
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* in interface or class descriptors; endpoints; I/O buffers; and so on.
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* @unbind: Reverses @bind; called as a side effect of unregistering the
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* driver which added this function.
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* @set_alt: (REQUIRED) Reconfigures altsettings; function drivers may
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* initialize usb_ep.driver data at this time (when it is used).
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* Note that setting an interface to its current altsetting resets
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* interface state, and that all interfaces have a disabled state.
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* @get_alt: Returns the active altsetting. If this is not provided,
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* then only altsetting zero is supported.
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* @disable: (REQUIRED) Indicates the function should be disabled. Reasons
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* include host resetting or reconfiguring the gadget, and disconnection.
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* @setup: Used for interface-specific control requests.
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* @suspend: Notifies functions when the host stops sending USB traffic.
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* @resume: Notifies functions when the host restarts USB traffic.
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*
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* A single USB function uses one or more interfaces, and should in most
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* cases support operation at both full and high speeds. Each function is
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* associated by @usb_add_function() with a one configuration; that function
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* causes @bind() to be called so resources can be allocated as part of
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* setting up a gadget driver. Those resources include endpoints, which
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* should be allocated using @usb_ep_autoconfig().
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*
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* To support dual speed operation, a function driver provides descriptors
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* for both high and full speed operation. Except in rare cases that don't
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* involve bulk endpoints, each speed needs different endpoint descriptors.
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*
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* Function drivers choose their own strategies for managing instance data.
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* The simplest strategy just declares it "static', which means the function
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* can only be activated once. If the function needs to be exposed in more
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* than one configuration at a given speed, it needs to support multiple
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* usb_function structures (one for each configuration).
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*
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* A more complex strategy might encapsulate a @usb_function structure inside
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* a driver-specific instance structure to allows multiple activations. An
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* example of multiple activations might be a CDC ACM function that supports
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* two or more distinct instances within the same configuration, providing
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* several independent logical data links to a USB host.
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*/
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struct usb_function {
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const char *name;
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struct usb_gadget_strings **strings;
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struct usb_descriptor_header **descriptors;
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struct usb_descriptor_header **hs_descriptors;
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struct usb_configuration *config;
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/* REVISIT: bind() functions can be marked __init, which
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* makes trouble for section mismatch analysis. See if
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* we can't restructure things to avoid mismatching.
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* Related: unbind() may kfree() but bind() won't...
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*/
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/* configuration management: bind/unbind */
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int (*bind)(struct usb_configuration *,
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struct usb_function *);
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void (*unbind)(struct usb_configuration *,
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struct usb_function *);
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/* runtime state management */
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int (*set_alt)(struct usb_function *,
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unsigned interface, unsigned alt);
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int (*get_alt)(struct usb_function *,
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unsigned interface);
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void (*disable)(struct usb_function *);
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int (*setup)(struct usb_function *,
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const struct usb_ctrlrequest *);
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void (*suspend)(struct usb_function *);
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void (*resume)(struct usb_function *);
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/* internals */
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struct list_head list;
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};
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int usb_add_function(struct usb_configuration *, struct usb_function *);
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int usb_interface_id(struct usb_configuration *, struct usb_function *);
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/**
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* ep_choose - select descriptor endpoint at current device speed
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* @g: gadget, connected and running at some speed
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* @hs: descriptor to use for high speed operation
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* @fs: descriptor to use for full or low speed operation
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*/
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static inline struct usb_endpoint_descriptor *
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ep_choose(struct usb_gadget *g, struct usb_endpoint_descriptor *hs,
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struct usb_endpoint_descriptor *fs)
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{
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if (gadget_is_dualspeed(g) && g->speed == USB_SPEED_HIGH)
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return hs;
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return fs;
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}
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#define MAX_CONFIG_INTERFACES 16 /* arbitrary; max 255 */
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/**
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* struct usb_configuration - represents one gadget configuration
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* @label: For diagnostics, describes the configuration.
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* @strings: Tables of strings, keyed by identifiers assigned during @bind()
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* and by language IDs provided in control requests.
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* @descriptors: Table of descriptors preceding all function descriptors.
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* Examples include OTG and vendor-specific descriptors.
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* @bind: Called from @usb_add_config() to allocate resources unique to this
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* configuration and to call @usb_add_function() for each function used.
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* @unbind: Reverses @bind; called as a side effect of unregistering the
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* driver which added this configuration.
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* @setup: Used to delegate control requests that aren't handled by standard
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* device infrastructure or directed at a specific interface.
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* @bConfigurationValue: Copied into configuration descriptor.
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* @iConfiguration: Copied into configuration descriptor.
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* @bmAttributes: Copied into configuration descriptor.
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* @bMaxPower: Copied into configuration descriptor.
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* @cdev: assigned by @usb_add_config() before calling @bind(); this is
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* the device associated with this configuration.
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*
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* Configurations are building blocks for gadget drivers structured around
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* function drivers. Simple USB gadgets require only one function and one
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* configuration, and handle dual-speed hardware by always providing the same
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* functionality. Slightly more complex gadgets may have more than one
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* single-function configuration at a given speed; or have configurations
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* that only work at one speed.
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*
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* Composite devices are, by definition, ones with configurations which
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* include more than one function.
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*
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* The lifecycle of a usb_configuration includes allocation, initialization
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* of the fields described above, and calling @usb_add_config() to set up
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* internal data and bind it to a specific device. The configuration's
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* @bind() method is then used to initialize all the functions and then
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* call @usb_add_function() for them.
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*
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* Those functions would normally be independant of each other, but that's
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* not mandatory. CDC WMC devices are an example where functions often
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* depend on other functions, with some functions subsidiary to others.
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* Such interdependency may be managed in any way, so long as all of the
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* descriptors complete by the time the composite driver returns from
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* its bind() routine.
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*/
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struct usb_configuration {
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const char *label;
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struct usb_gadget_strings **strings;
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const struct usb_descriptor_header **descriptors;
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/* REVISIT: bind() functions can be marked __init, which
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* makes trouble for section mismatch analysis. See if
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* we can't restructure things to avoid mismatching...
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*/
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/* configuration management: bind/unbind */
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int (*bind)(struct usb_configuration *);
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void (*unbind)(struct usb_configuration *);
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int (*setup)(struct usb_configuration *,
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const struct usb_ctrlrequest *);
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/* fields in the config descriptor */
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u8 bConfigurationValue;
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u8 iConfiguration;
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u8 bmAttributes;
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u8 bMaxPower;
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struct usb_composite_dev *cdev;
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/* internals */
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struct list_head list;
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struct list_head functions;
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u8 next_interface_id;
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unsigned highspeed:1;
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unsigned fullspeed:1;
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struct usb_function *interface[MAX_CONFIG_INTERFACES];
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};
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int usb_add_config(struct usb_composite_dev *,
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struct usb_configuration *);
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/**
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* struct usb_composite_driver - groups configurations into a gadget
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* @name: For diagnostics, identifies the driver.
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* @dev: Template descriptor for the device, including default device
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* identifiers.
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* @strings: tables of strings, keyed by identifiers assigned during bind()
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* and language IDs provided in control requests
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* @bind: (REQUIRED) Used to allocate resources that are shared across the
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* whole device, such as string IDs, and add its configurations using
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* @usb_add_config(). This may fail by returning a negative errno
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* value; it should return zero on successful initialization.
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* @unbind: Reverses @bind(); called as a side effect of unregistering
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* this driver.
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*
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* Devices default to reporting self powered operation. Devices which rely
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* on bus powered operation should report this in their @bind() method.
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*
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* Before returning from @bind, various fields in the template descriptor
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* may be overridden. These include the idVendor/idProduct/bcdDevice values
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* normally to bind the appropriate host side driver, and the three strings
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* (iManufacturer, iProduct, iSerialNumber) normally used to provide user
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* meaningful device identifiers. (The strings will not be defined unless
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* they are defined in @dev and @strings.) The correct ep0 maxpacket size
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* is also reported, as defined by the underlying controller driver.
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*/
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struct usb_composite_driver {
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const char *name;
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const struct usb_device_descriptor *dev;
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struct usb_gadget_strings **strings;
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/* REVISIT: bind() functions can be marked __init, which
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* makes trouble for section mismatch analysis. See if
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* we can't restructure things to avoid mismatching...
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*/
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int (*bind)(struct usb_composite_dev *);
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int (*unbind)(struct usb_composite_dev *);
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};
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extern int usb_composite_register(struct usb_composite_driver *);
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extern void usb_composite_unregister(struct usb_composite_driver *);
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/**
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* struct usb_composite_device - represents one composite usb gadget
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* @gadget: read-only, abstracts the gadget's usb peripheral controller
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* @req: used for control responses; buffer is pre-allocated
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* @bufsiz: size of buffer pre-allocated in @req
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* @config: the currently active configuration
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*
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* One of these devices is allocated and initialized before the
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* associated device driver's bind() is called.
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*
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* OPEN ISSUE: it appears that some WUSB devices will need to be
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* built by combining a normal (wired) gadget with a wireless one.
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* This revision of the gadget framework should probably try to make
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* sure doing that won't hurt too much.
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*
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* One notion for how to handle Wireless USB devices involves:
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* (a) a second gadget here, discovery mechanism TBD, but likely
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* needing separate "register/unregister WUSB gadget" calls;
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* (b) updates to usb_gadget to include flags "is it wireless",
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* "is it wired", plus (presumably in a wrapper structure)
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* bandgroup and PHY info;
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* (c) presumably a wireless_ep wrapping a usb_ep, and reporting
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* wireless-specific parameters like maxburst and maxsequence;
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* (d) configurations that are specific to wireless links;
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* (e) function drivers that understand wireless configs and will
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* support wireless for (additional) function instances;
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* (f) a function to support association setup (like CBAF), not
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* necessarily requiring a wireless adapter;
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* (g) composite device setup that can create one or more wireless
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* configs, including appropriate association setup support;
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* (h) more, TBD.
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*/
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struct usb_composite_dev {
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struct usb_gadget *gadget;
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struct usb_request *req;
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unsigned bufsiz;
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struct usb_configuration *config;
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/* internals */
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struct usb_device_descriptor desc;
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struct list_head configs;
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struct usb_composite_driver *driver;
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u8 next_string_id;
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spinlock_t lock;
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/* REVISIT use and existence of lock ... */
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};
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extern int usb_string_id(struct usb_composite_dev *c);
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/* messaging utils */
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#define DBG(d, fmt, args...) \
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dev_dbg(&(d)->gadget->dev , fmt , ## args)
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#define VDBG(d, fmt, args...) \
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dev_vdbg(&(d)->gadget->dev , fmt , ## args)
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#define ERROR(d, fmt, args...) \
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dev_err(&(d)->gadget->dev , fmt , ## args)
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#define WARN(d, fmt, args...) \
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dev_warn(&(d)->gadget->dev , fmt , ## args)
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#define INFO(d, fmt, args...) \
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dev_info(&(d)->gadget->dev , fmt , ## args)
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#endif /* __LINUX_USB_COMPOSITE_H */
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