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Diffstat (limited to 'include/linux/usb/composite.h')
| -rw-r--r-- | include/linux/usb/composite.h | 338 |
1 files changed, 338 insertions, 0 deletions
diff --git a/include/linux/usb/composite.h b/include/linux/usb/composite.h new file mode 100644 index 00000000000..747c3a49cdc --- /dev/null +++ b/include/linux/usb/composite.h @@ -0,0 +1,338 @@ +/* + * composite.h -- framework for usb gadgets which are composite devices + * + * Copyright (C) 2006-2008 David Brownell + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA + */ + +#ifndef __LINUX_USB_COMPOSITE_H +#define __LINUX_USB_COMPOSITE_H + +/* + * This framework is an optional layer on top of the USB Gadget interface, + * making it easier to build (a) Composite devices, supporting multiple + * functions within any single configuration, and (b) Multi-configuration + * devices, also supporting multiple functions but without necessarily + * having more than one function per configuration. + * + * Example: a device with a single configuration supporting both network + * link and mass storage functions is a composite device. Those functions + * might alternatively be packaged in individual configurations, but in + * the composite model the host can use both functions at the same time. + */ + +#include <linux/usb/ch9.h> +#include <linux/usb/gadget.h> + + +struct usb_configuration; + +/** + * struct usb_function - describes one function of a configuration + * @name: For diagnostics, identifies the function. + * @strings: tables of strings, keyed by identifiers assigned during bind() + * and by language IDs provided in control requests + * @descriptors: Table of full (or low) speed descriptors, using interface and + * string identifiers assigned during @bind(). If this pointer is null, + * the function will not be available at full speed (or at low speed). + * @hs_descriptors: Table of high speed descriptors, using interface and + * string identifiers assigned during @bind(). If this pointer is null, + * the function will not be available at high speed. + * @config: assigned when @usb_add_function() is called; this is the + * configuration with which this function is associated. + * @bind: Before the gadget can register, all of its functions bind() to the + * available resources including string and interface identifiers used + * in interface or class descriptors; endpoints; I/O buffers; and so on. + * @unbind: Reverses @bind; called as a side effect of unregistering the + * driver which added this function. + * @set_alt: (REQUIRED) Reconfigures altsettings; function drivers may + * initialize usb_ep.driver data at this time (when it is used). + * Note that setting an interface to its current altsetting resets + * interface state, and that all interfaces have a disabled state. + * @get_alt: Returns the active altsetting. If this is not provided, + * then only altsetting zero is supported. + * @disable: (REQUIRED) Indicates the function should be disabled. Reasons + * include host resetting or reconfiguring the gadget, and disconnection. + * @setup: Used for interface-specific control requests. + * @suspend: Notifies functions when the host stops sending USB traffic. + * @resume: Notifies functions when the host restarts USB traffic. + * + * A single USB function uses one or more interfaces, and should in most + * cases support operation at both full and high speeds. Each function is + * associated by @usb_add_function() with a one configuration; that function + * causes @bind() to be called so resources can be allocated as part of + * setting up a gadget driver. Those resources include endpoints, which + * should be allocated using @usb_ep_autoconfig(). + * + * To support dual speed operation, a function driver provides descriptors + * for both high and full speed operation. Except in rare cases that don't + * involve bulk endpoints, each speed needs different endpoint descriptors. + * + * Function drivers choose their own strategies for managing instance data. + * The simplest strategy just declares it "static', which means the function + * can only be activated once. If the function needs to be exposed in more + * than one configuration at a given speed, it needs to support multiple + * usb_function structures (one for each configuration). + * + * A more complex strategy might encapsulate a @usb_function structure inside + * a driver-specific instance structure to allows multiple activations. An + * example of multiple activations might be a CDC ACM function that supports + * two or more distinct instances within the same configuration, providing + * several independent logical data links to a USB host. + */ +struct usb_function { + const char *name; + struct usb_gadget_strings **strings; + struct usb_descriptor_header **descriptors; + struct usb_descriptor_header **hs_descriptors; + + struct usb_configuration *config; + + /* REVISIT: bind() functions can be marked __init, which + * makes trouble for section mismatch analysis. See if + * we can't restructure things to avoid mismatching. + * Related: unbind() may kfree() but bind() won't... + */ + + /* configuration management: bind/unbind */ + int (*bind)(struct usb_configuration *, + struct usb_function *); + void (*unbind)(struct usb_configuration *, + struct usb_function *); + + /* runtime state management */ + int (*set_alt)(struct usb_function *, + unsigned interface, unsigned alt); + int (*get_alt)(struct usb_function *, + unsigned interface); + void (*disable)(struct usb_function *); + int (*setup)(struct usb_function *, + const struct usb_ctrlrequest *); + void (*suspend)(struct usb_function *); + void (*resume)(struct usb_function *); + + /* internals */ + struct list_head list; +}; + +int usb_add_function(struct usb_configuration *, struct usb_function *); + +int usb_interface_id(struct usb_configuration *, struct usb_function *); + +/** + * ep_choose - select descriptor endpoint at current device speed + * @g: gadget, connected and running at some speed + * @hs: descriptor to use for high speed operation + * @fs: descriptor to use for full or low speed operation + */ +static inline struct usb_endpoint_descriptor * +ep_choose(struct usb_gadget *g, struct usb_endpoint_descriptor *hs, + struct usb_endpoint_descriptor *fs) +{ + if (gadget_is_dualspeed(g) && g->speed == USB_SPEED_HIGH) + return hs; + return fs; +} + +#define MAX_CONFIG_INTERFACES 16 /* arbitrary; max 255 */ + +/** + * struct usb_configuration - represents one gadget configuration + * @label: For diagnostics, describes the configuration. + * @strings: Tables of strings, keyed by identifiers assigned during @bind() + * and by language IDs provided in control requests. + * @descriptors: Table of descriptors preceding all function descriptors. + * Examples include OTG and vendor-specific descriptors. + * @bind: Called from @usb_add_config() to allocate resources unique to this + * configuration and to call @usb_add_function() for each function used. + * @unbind: Reverses @bind; called as a side effect of unregistering the + * driver which added this configuration. + * @setup: Used to delegate control requests that aren't handled by standard + * device infrastructure or directed at a specific interface. + * @bConfigurationValue: Copied into configuration descriptor. + * @iConfiguration: Copied into configuration descriptor. + * @bmAttributes: Copied into configuration descriptor. + * @bMaxPower: Copied into configuration descriptor. + * @cdev: assigned by @usb_add_config() before calling @bind(); this is + * the device associated with this configuration. + * + * Configurations are building blocks for gadget drivers structured around + * function drivers. Simple USB gadgets require only one function and one + * configuration, and handle dual-speed hardware by always providing the same + * functionality. Slightly more complex gadgets may have more than one + * single-function configuration at a given speed; or have configurations + * that only work at one speed. + * + * Composite devices are, by definition, ones with configurations which + * include more than one function. + * + * The lifecycle of a usb_configuration includes allocation, initialization + * of the fields described above, and calling @usb_add_config() to set up + * internal data and bind it to a specific device. The configuration's + * @bind() method is then used to initialize all the functions and then + * call @usb_add_function() for them. + * + * Those functions would normally be independant of each other, but that's + * not mandatory. CDC WMC devices are an example where functions often + * depend on other functions, with some functions subsidiary to others. + * Such interdependency may be managed in any way, so long as all of the + * descriptors complete by the time the composite driver returns from + * its bind() routine. + */ +struct usb_configuration { + const char *label; + struct usb_gadget_strings **strings; + const struct usb_descriptor_header **descriptors; + + /* REVISIT: bind() functions can be marked __init, which + * makes trouble for section mismatch analysis. See if + * we can't restructure things to avoid mismatching... + */ + + /* configuration management: bind/unbind */ + int (*bind)(struct usb_configuration *); + void (*unbind)(struct usb_configuration *); + int (*setup)(struct usb_configuration *, + const struct usb_ctrlrequest *); + + /* fields in the config descriptor */ + u8 bConfigurationValue; + u8 iConfiguration; + u8 bmAttributes; + u8 bMaxPower; + + struct usb_composite_dev *cdev; + + /* internals */ + struct list_head list; + struct list_head functions; + u8 next_interface_id; + unsigned highspeed:1; + unsigned fullspeed:1; + struct usb_function *interface[MAX_CONFIG_INTERFACES]; +}; + +int usb_add_config(struct usb_composite_dev *, + struct usb_configuration *); + +/** + * struct usb_composite_driver - groups configurations into a gadget + * @name: For diagnostics, identifies the driver. + * @dev: Template descriptor for the device, including default device + * identifiers. + * @strings: tables of strings, keyed by identifiers assigned during bind() + * and language IDs provided in control requests + * @bind: (REQUIRED) Used to allocate resources that are shared across the + * whole device, such as string IDs, and add its configurations using + * @usb_add_config(). This may fail by returning a negative errno + * value; it should return zero on successful initialization. + * @unbind: Reverses @bind(); called as a side effect of unregistering + * this driver. + * + * Devices default to reporting self powered operation. Devices which rely + * on bus powered operation should report this in their @bind() method. + * + * Before returning from @bind, various fields in the template descriptor + * may be overridden. These include the idVendor/idProduct/bcdDevice values + * normally to bind the appropriate host side driver, and the three strings + * (iManufacturer, iProduct, iSerialNumber) normally used to provide user + * meaningful device identifiers. (The strings will not be defined unless + * they are defined in @dev and @strings.) The correct ep0 maxpacket size + * is also reported, as defined by the underlying controller driver. + */ +struct usb_composite_driver { + const char *name; + const struct usb_device_descriptor *dev; + struct usb_gadget_strings **strings; + + /* REVISIT: bind() functions can be marked __init, which + * makes trouble for section mismatch analysis. See if + * we can't restructure things to avoid mismatching... + */ + + int (*bind)(struct usb_composite_dev *); + int (*unbind)(struct usb_composite_dev *); +}; + +extern int usb_composite_register(struct usb_composite_driver *); +extern void usb_composite_unregister(struct usb_composite_driver *); + + +/** + * struct usb_composite_device - represents one composite usb gadget + * @gadget: read-only, abstracts the gadget's usb peripheral controller + * @req: used for control responses; buffer is pre-allocated + * @bufsiz: size of buffer pre-allocated in @req + * @config: the currently active configuration + * + * 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. + */ +struct usb_composite_dev { + struct usb_gadget *gadget; + struct usb_request *req; + unsigned bufsiz; + + struct usb_configuration *config; + + /* internals */ + struct usb_device_descriptor desc; + struct list_head configs; + struct usb_composite_driver *driver; + u8 next_string_id; + + spinlock_t lock; + + /* REVISIT use and existence of lock ... */ +}; + +extern int usb_string_id(struct usb_composite_dev *c); + +/* messaging utils */ +#define DBG(d, fmt, args...) \ + dev_dbg(&(d)->gadget->dev , fmt , ## args) +#define VDBG(d, fmt, args...) \ + dev_vdbg(&(d)->gadget->dev , fmt , ## args) +#define ERROR(d, fmt, args...) \ + dev_err(&(d)->gadget->dev , fmt , ## args) +#define WARN(d, fmt, args...) \ + dev_warn(&(d)->gadget->dev , fmt , ## args) +#define INFO(d, fmt, args...) \ + dev_info(&(d)->gadget->dev , fmt , ## args) + +#endif /* __LINUX_USB_COMPOSITE_H */ |