http://www.ousob.com --- Legacy Redefined OuSob - File: /wwwroot/clipx/usr/include/linux/usb_gadget.h

/* * <linux/usb_gadget.h> * * We call the USB code inside a Linux-based peripheral device a "gadget" * driver, except for the hardware-specific bus glue. One USB host can * master many USB gadgets, but the gadgets are only slaved to one host. * * * (C) Copyright 2002-2004 by David Brownell * All Rights Reserved. * * This software is licensed under the GNU GPL version 2. */ #ifndef __LINUX_USB_GADGET_H #define __LINUX_USB_GADGET_H #ifdef __KERNEL__ struct usb_ep; /** * struct usb_request - describes one i/o request * @buf: Buffer used for data. Always provide this; some controllers * only use PIO, or don't use DMA for some endpoints. * @dma: DMA address corresponding to 'buf'. If you don't set this * field, and the usb controller needs one, it is responsible * for mapping and unmapping the buffer. * @length: Length of that data * @no_interrupt: If true, hints that no completion irq is needed. * Helpful sometimes with deep request queues that are handled * directly by DMA controllers. * @zero: If true, when writing data, makes the last packet be "short" * by adding a zero length packet as needed; * @short_not_ok: When reading data, makes short packets be * treated as errors (queue stops advancing till cleanup). * @complete: Function called when request completes, so this request and * its buffer may be re-used. * Reads terminate with a short packet, or when the buffer fills, * whichever comes first. When writes terminate, some data bytes * will usually still be in flight (often in a hardware fifo). * Errors (for reads or writes) stop the queue from advancing * until the completion function returns, so that any transfers * invalidated by the error may first be dequeued. * @context: For use by the completion callback * @list: For use by the gadget driver. * @status: Reports completion code, zero or a negative errno. * Normally, faults block the transfer queue from advancing until * the completion callback returns. * Code "-ESHUTDOWN" indicates completion caused by device disconnect, * or when the driver disabled the endpoint. * @actual: Reports bytes transferred to/from the buffer. For reads (OUT * transfers) this may be less than the requested length. If the * short_not_ok flag is set, short reads are treated as errors * even when status otherwise indicates successful completion. * Note that for writes (IN transfers) some data bytes may still * reside in a device-side FIFO when the request is reported as * complete. * * These are allocated/freed through the endpoint they're used with. The * hardware's driver can add extra per-request data to the memory it returns, * which often avoids separate memory allocations (potential failures), * later when the request is queued. * * Request flags affect request handling, such as whether a zero length * packet is written (the "zero" flag), whether a short read should be * treated as an error (blocking request queue advance, the "short_not_ok" * flag), or hinting that an interrupt is not required (the "no_interrupt" * flag, for use with deep request queues). * * Bulk endpoints can use any size buffers, and can also be used for interrupt * transfers. interrupt-only endpoints can be much less functional. */ // NOTE this is analagous to 'struct urb' on the host side, // except that it's thinner and promotes more pre-allocation. struct usb_request { void *buf; unsigned length; dma_addr_t dma; unsigned no_interrupt:1; unsigned zero:1; unsigned short_not_ok:1; void (*complete)(struct usb_ep *ep, struct usb_request *req); void *context; struct list_head list; int status; unsigned actual; }; /*-------------------------------------------------------------------------*/ /* endpoint-specific parts of the api to the usb controller hardware. * unlike the urb model, (de)multiplexing layers are not required. * (so this api could slash overhead if used on the host side...) * * note that device side usb controllers commonly differ in how many * endpoints they support, as well as their capabilities. */ struct usb_ep_ops { int (*enable) (struct usb_ep *ep, const struct usb_endpoint_descriptor *desc); int (*disable) (struct usb_ep *ep); struct usb_request *(*alloc_request) (struct usb_ep *ep, gfp_t gfp_flags); void (*free_request) (struct usb_ep *ep, struct usb_request *req); void *(*alloc_buffer) (struct usb_ep *ep, unsigned bytes, dma_addr_t *dma, gfp_t gfp_flags); void (*free_buffer) (struct usb_ep *ep, void *buf, dma_addr_t dma, unsigned bytes); // NOTE: on 2.6, drivers may also use dma_map() and // dma_sync_single_*() to directly manage dma overhead. int (*queue) (struct usb_ep *ep, struct usb_request *req, gfp_t gfp_flags); int (*dequeue) (struct usb_ep *ep, struct usb_request *req); int (*set_halt) (struct usb_ep *ep, int value); int (*fifo_status) (struct usb_ep *ep); void (*fifo_flush) (struct usb_ep *ep); }; /** * struct usb_ep - device side representation of USB endpoint * @name:identifier for the endpoint, such as "ep-a" or "ep9in-bulk" * @ops: Function pointers used to access hardware-specific operations. * @ep_list:the gadget's ep_list holds all of its endpoints * @maxpacket:The maximum packet size used on this endpoint. The initial * value can sometimes be reduced (hardware allowing), according to * the endpoint descriptor used to configure the endpoint. * @driver_data:for use by the gadget driver. all other fields are * read-only to gadget drivers. * * the bus controller driver lists all the general purpose endpoints in * gadget->ep_list. the control endpoint (gadget->ep0) is not in that list, * and is accessed only in response to a driver setup() callback. */ struct usb_ep { void *driver_data; const char *name; const struct usb_ep_ops *ops; struct list_head ep_list; unsigned maxpacket:16; }; /*-------------------------------------------------------------------------*/ /** * usb_ep_enable - configure endpoint, making it usable * @ep:the endpoint being configured. may not be the endpoint named "ep0". * drivers discover endpoints through the ep_list of a usb_gadget. * @desc:descriptor for desired behavior. caller guarantees this pointer * remains valid until the endpoint is disabled; the data byte order * is little-endian (usb-standard). * * when configurations are set, or when interface settings change, the driver * will enable or disable the relevant endpoints. while it is enabled, an * endpoint may be used for i/o until the driver receives a disconnect() from * the host or until the endpoint is disabled. * * the ep0 implementation (which calls this routine) must ensure that the * hardware capabilities of each endpoint match the descriptor provided * for it. for example, an endpoint named "ep2in-bulk" would be usable * for interrupt transfers as well as bulk, but it likely couldn't be used * for iso transfers or for endpoint 14. some endpoints are fully * configurable, with more generic names like "ep-a". (remember that for * USB, "in" means "towards the USB master".) * * returns zero, or a negative error code. */ static inline int usb_ep_enable (struct usb_ep *ep, const struct usb_endpoint_descriptor *desc) { return ep->ops->enable (ep, desc); } /** * usb_ep_disable - endpoint is no longer usable * @ep:the endpoint being unconfigured. may not be the endpoint named "ep0". * * no other task may be using this endpoint when this is called. * any pending and uncompleted requests will complete with status * indicating disconnect (-ESHUTDOWN) before this call returns. * gadget drivers must call usb_ep_enable() again before queueing * requests to the endpoint. * * returns zero, or a negative error code. */ static inline int usb_ep_disable (struct usb_ep *ep) { return ep->ops->disable (ep); } /** * usb_ep_alloc_request - allocate a request object to use with this endpoint * @ep:the endpoint to be used with with the request * @gfp_flags:GFP_* flags to use * * Request objects must be allocated with this call, since they normally * need controller-specific setup and may even need endpoint-specific * resources such as allocation of DMA descriptors. * Requests may be submitted with usb_ep_queue(), and receive a single * completion callback. Free requests with usb_ep_free_request(), when * they are no longer needed. * * Returns the request, or null if one could not be allocated. */ static inline struct usb_request * usb_ep_alloc_request (struct usb_ep *ep, gfp_t gfp_flags) { return ep->ops->alloc_request (ep, gfp_flags); } /** * usb_ep_free_request - frees a request object * @ep:the endpoint associated with the request * @req:the request being freed * * Reverses the effect of usb_ep_alloc_request(). * Caller guarantees the request is not queued, and that it will * no longer be requeued (or otherwise used). */ static inline void usb_ep_free_request (struct usb_ep *ep, struct usb_request *req) { ep->ops->free_request (ep, req); } /** * usb_ep_alloc_buffer - allocate an I/O buffer * @ep:the endpoint associated with the buffer * @len:length of the desired buffer * @dma:pointer to the buffer's DMA address; must be valid * @gfp_flags:GFP_* flags to use * * Returns a new buffer, or null if one could not be allocated. * The buffer is suitably aligned for dma, if that endpoint uses DMA, * and the caller won't have to care about dma-inconsistency * or any hidden "bounce buffer" mechanism. No additional per-request * DMA mapping will be required for such buffers. * Free it later with usb_ep_free_buffer(). * * You don't need to use this call to allocate I/O buffers unless you * want to make sure drivers don't incur costs for such "bounce buffer" * copies or per-request DMA mappings. */ static inline void * usb_ep_alloc_buffer (struct usb_ep *ep, unsigned len, dma_addr_t *dma, gfp_t gfp_flags) { return ep->ops->alloc_buffer (ep, len, dma, gfp_flags); } /** * usb_ep_free_buffer - frees an i/o buffer * @ep:the endpoint associated with the buffer * @buf:CPU view address of the buffer * @dma:the buffer's DMA address * @len:length of the buffer * * reverses the effect of usb_ep_alloc_buffer(). * caller guarantees the buffer will no longer be accessed */ static inline void usb_ep_free_buffer (struct usb_ep *ep, void *buf, dma_addr_t dma, unsigned len) { ep->ops->free_buffer (ep, buf, dma, len); } /** * usb_ep_queue - queues (submits) an I/O request to an endpoint. * @ep:the endpoint associated with the request * @req:the request being submitted * @gfp_flags: GFP_* flags to use in case the lower level driver couldn't * pre-allocate all necessary memory with the request. * * This tells the device controller to perform the specified request through * that endpoint (reading or writing a buffer). When the request completes, * including being canceled by usb_ep_dequeue(), the request's completion * routine is called to return the request to the driver. Any endpoint * (except control endpoints like ep0) may have more than one transfer * request queued; they complete in FIFO order. Once a gadget driver * submits a request, that request may not be examined or modified until it * is given back to that driver through the completion callback. * * Each request is turned into one or more packets. The controller driver * never merges adjacent requests into the same packet. OUT transfers * will sometimes use data that's already buffered in the hardware. * Drivers can rely on the fact that the first byte of the request's buffer * always corresponds to the first byte of some USB packet, for both * IN and OUT transfers. * * Bulk endpoints can queue any amount of data; the transfer is packetized * automatically. The last packet will be short if the request doesn't fill it * out completely. Zero length packets (ZLPs) should be avoided in portable * protocols since not all usb hardware can successfully handle zero length * packets. (ZLPs may be explicitly written, and may be implicitly written if * the request 'zero' flag is set.) Bulk endpoints may also be used * for interrupt transfers; but the reverse is not true, and some endpoints * won't support every interrupt transfer. (Such as 768 byte packets.) * * Interrupt-only endpoints are less functional than bulk endpoints, for * example by not supporting queueing or not handling buffers that are * larger than the endpoint's maxpacket size. They may also treat data * toggle differently. * * Control endpoints ... after getting a setup() callback, the driver queues * one response (even if it would be zero length). That enables the * status ack, after transfering data as specified in the response. Setup * functions may return negative error codes to generate protocol stalls. * (Note that some USB device controllers disallow protocol stall responses * in some cases.) When control responses are deferred (the response is * written after the setup callback returns), then usb_ep_set_halt() may be * used on ep0 to trigger protocol stalls. * * For periodic endpoints, like interrupt or isochronous ones, the usb host * arranges to poll once per interval, and the gadget driver usually will * have queued some data to transfer at that time. * * Returns zero, or a negative error code. Endpoints that are not enabled * report errors; errors will also be * reported when the usb peripheral is disconnected. */ static inline int usb_ep_queue (struct usb_ep *ep, struct usb_request *req, gfp_t gfp_flags) { return ep->ops->queue (ep, req, gfp_flags); } /** * usb_ep_dequeue - dequeues (cancels, unlinks) an I/O request from an endpoint * @ep:the endpoint associated with the request * @req:the request being canceled * * if the request is still active on the endpoint, it is dequeued and its * completion routine is called (with status -ECONNRESET); else a negative * error code is returned. * * note that some hardware can't clear out write fifos (to unlink the request * at the head of the queue) except as part of disconnecting from usb. such * restrictions prevent drivers from supporting configuration changes, * even to configuration zero (a "chapter 9" requirement). */ static inline int usb_ep_dequeue (struct usb_ep *ep, struct usb_request *req) { return ep->ops->dequeue (ep, req); } /** * usb_ep_set_halt - sets the endpoint halt feature. * @ep: the non-isochronous endpoint being stalled * * Use this to stall an endpoint, perhaps as an error report. * Except for control endpoints, * the endpoint stays halted (will not stream any data) until the host * clears this feature; drivers may need to empty the endpoint's request * queue first, to make sure no inappropriate transfers happen. * * Note that while an endpoint CLEAR_FEATURE will be invisible to the * gadget driver, a SET_INTERFACE will not be. To reset endpoints for the * current altsetting, see usb_ep_clear_halt(). When switching altsettings, * it's simplest to use usb_ep_enable() or usb_ep_disable() for the endpoints. * * Returns zero, or a negative error code. On success, this call sets * underlying hardware state that blocks data transfers. * Attempts to halt IN endpoints will fail (returning -EAGAIN) if any * transfer requests are still queued, or if the controller hardware * (usually a FIFO) still holds bytes that the host hasn't collected. */ static inline int usb_ep_set_halt (struct usb_ep *ep) { return ep->ops->set_halt (ep, 1); } /** * usb_ep_clear_halt - clears endpoint halt, and resets toggle * @ep:the bulk or interrupt endpoint being reset * * Use this when responding to the standard usb "set interface" request, * for endpoints that aren't reconfigured, after clearing any other state * in the endpoint's i/o queue. * * Returns zero, or a negative error code. On success, this call clears * the underlying hardware state reflecting endpoint halt and data toggle. * Note that some hardware can't support this request (like pxa2xx_udc), * and accordingly can't correctly implement interface altsettings. */ static inline int usb_ep_clear_halt (struct usb_ep *ep) { return ep->ops->set_halt (ep, 0); } /** * usb_ep_fifo_status - returns number of bytes in fifo, or error * @ep: the endpoint whose fifo status is being checked. * * FIFO endpoints may have "unclaimed data" in them in certain cases, * such as after aborted transfers. Hosts may not have collected all * the IN data written by the gadget driver (and reported by a request * completion). The gadget driver may not have collected all the data * written OUT to it by the host. Drivers that need precise handling for * fault reporting or recovery may need to use this call. * * This returns the number of such bytes in the fifo, or a negative * errno if the endpoint doesn't use a FIFO or doesn't support such * precise handling. */ static inline int usb_ep_fifo_status (struct usb_ep *ep) { if (ep->ops->fifo_status) return ep->ops->fifo_status (ep); else return -EOPNOTSUPP; } /** * usb_ep_fifo_flush - flushes contents of a fifo * @ep: the endpoint whose fifo is being flushed. * * This call may be used to flush the "unclaimed data" that may exist in * an endpoint fifo after abnormal transaction terminations. The call * must never be used except when endpoint is not being used for any * protocol translation. */ static inline void usb_ep_fifo_flush (struct usb_ep *ep) { if (ep->ops->fifo_flush) ep->ops->fifo_flush (ep); } /*-------------------------------------------------------------------------*/ struct usb_gadget; /* the rest of the api to the controller hardware: device operations, * which don't involve endpoints (or i/o). */ struct usb_gadget_ops { int (*get_frame)(struct usb_gadget *); int (*wakeup)(struct usb_gadget *); int (*set_selfpowered) (struct usb_gadget *, int is_selfpowered); int (*vbus_session) (struct usb_gadget *, int is_active); int (*vbus_draw) (struct usb_gadget *, unsigned mA); int (*pullup) (struct usb_gadget *, int is_on); int (*ioctl)(struct usb_gadget *, unsigned code, unsigned long param); }; /** * struct usb_gadget - represents a usb slave device * @ops: Function pointers used to access hardware-specific operations. * @ep0: Endpoint zero, used when reading or writing responses to * driver setup() requests * @ep_list: List of other endpoints supported by the device. * @speed: Speed of current connection to USB host. * @is_dualspeed: True if the controller supports both high and full speed * operation. If it does, the gadget driver must also support both. * @is_otg: True if the USB device port uses a Mini-AB jack, so that the * gadget driver must provide a USB OTG descriptor. * @is_a_peripheral: False unless is_otg, the "A" end of a USB cable * is in the Mini-AB jack, and HNP has been used to switch roles * so that the "A" device currently acts as A-Peripheral, not A-Host. * @a_hnp_support: OTG device feature flag, indicating that the A-Host * supports HNP at this port. * @a_alt_hnp_support: OTG device feature flag, indicating that the A-Host * only supports HNP on a different root port. * @b_hnp_enable: OTG device feature flag, indicating that the A-Host * enabled HNP support. * @name: Identifies the controller hardware type. Used in diagnostics * and sometimes configuration. * @dev: Driver model state for this abstract device. * * Gadgets have a mostly-portable "gadget driver" implementing device * functions, handling all usb configurations and interfaces. Gadget * drivers talk to hardware-specific code indirectly, through ops vectors. * That insulates the gadget driver from hardware details, and packages * the hardware endpoints through generic i/o queues. The "usb_gadget" * and "usb_ep" interfaces provide that insulation from the hardware. * * Except for the driver data, all fields in this structure are * read-only to the gadget driver. That driver data is part of the * "driver model" infrastructure in 2.6 (and later) kernels, and for * earlier systems is grouped in a similar structure that's not known * to the rest of the kernel. * * Values of the three OTG device feature flags are updated before the * setup() call corresponding to USB_REQ_SET_CONFIGURATION, and before * driver suspend() calls. They are valid only when is_otg, and when the * device is acting as a B-Peripheral (so is_a_peripheral is false). */ struct usb_gadget { /* readonly to gadget driver */ const struct usb_gadget_ops *ops; struct usb_ep *ep0; struct list_head ep_list; /* of usb_ep */ enum usb_device_speed speed; unsigned is_dualspeed:1; unsigned is_otg:1; unsigned is_a_peripheral:1; unsigned b_hnp_enable:1; unsigned a_hnp_support:1; unsigned a_alt_hnp_support:1; const char *name; struct device dev; }; static inline void set_gadget_data (struct usb_gadget *gadget, void *data) { dev_set_drvdata (&gadget->dev, data); } static inline void *get_gadget_data (struct usb_gadget *gadget) { return dev_get_drvdata (&gadget->dev); } /* iterates the non-control endpoints; 'tmp' is a struct usb_ep pointer */ #define gadget_for_each_ep(tmp,gadget) \ list_for_each_entry(tmp, &(gadget)->ep_list, ep_list) /** * usb_gadget_frame_number - returns the current frame number * @gadget: controller that reports the frame number * * Returns the usb frame number, normally eleven bits from a SOF packet, * or negative errno if this device doesn't support this capability. */ static inline int usb_gadget_frame_number (struct usb_gadget *gadget) { return gadget->ops->get_frame (gadget); } /** * usb_gadget_wakeup - tries to wake up the host connected to this gadget * @gadget: controller used to wake up the host * * Returns zero on success, else negative error code if the hardware * doesn't support such attempts, or its support has not been enabled * by the usb host. Drivers must return device descriptors that report * their ability to support this, or hosts won't enable it. * * This may also try to use SRP to wake the host and start enumeration, * even if OTG isn't otherwise in use. OTG devices may also start * remote wakeup even when hosts don't explicitly enable it. */ static inline int usb_gadget_wakeup (struct usb_gadget *gadget) { if (!gadget->ops->wakeup) return -EOPNOTSUPP; return gadget->ops->wakeup (gadget); } /** * usb_gadget_set_selfpowered - sets the device selfpowered feature. * @gadget:the device being declared as self-powered * * this affects the device status reported by the hardware driver * to reflect that it now has a local power supply. * * returns zero on success, else negative errno. */ static inline int usb_gadget_set_selfpowered (struct usb_gadget *gadget) { if (!gadget->ops->set_selfpowered) return -EOPNOTSUPP; return gadget->ops->set_selfpowered (gadget, 1); } /** * usb_gadget_clear_selfpowered - clear the device selfpowered feature. * @gadget:the device being declared as bus-powered * * this affects the device status reported by the hardware driver. * some hardware may not support bus-powered operation, in which * case this feature's value can never change. * * returns zero on success, else negative errno. */ static inline int usb_gadget_clear_selfpowered (struct usb_gadget *gadget) { if (!gadget->ops->set_selfpowered) return -EOPNOTSUPP; return gadget->ops->set_selfpowered (gadget, 0); } /** * usb_gadget_vbus_connect - Notify controller that VBUS is powered * @gadget:The device which now has VBUS power. * * This call is used by a driver for an external transceiver (or GPIO) * that detects a VBUS power session starting. Common responses include * resuming the controller, activating the D+ (or D-) pullup to let the * host detect that a USB device is attached, and starting to draw power * (8mA or possibly more, especially after SET_CONFIGURATION). * * Returns zero on success, else negative errno. */ static inline int usb_gadget_vbus_connect(struct usb_gadget *gadget) { if (!gadget->ops->vbus_session) return -EOPNOTSUPP; return gadget->ops->vbus_session (gadget, 1); } /** * usb_gadget_vbus_draw - constrain controller's VBUS power usage * @gadget:The device whose VBUS usage is being described * @mA:How much current to draw, in milliAmperes. This should be twice * the value listed in the configuration descriptor bMaxPower field. * * This call is used by gadget drivers during SET_CONFIGURATION calls, * reporting how much power the device may consume. For example, this * could affect how quickly batteries are recharged. * * Returns zero on success, else negative errno. */ static inline int usb_gadget_vbus_draw(struct usb_gadget *gadget, unsigned mA) { if (!gadget->ops->vbus_draw) return -EOPNOTSUPP; return gadget->ops->vbus_draw (gadget, mA); } /** * usb_gadget_vbus_disconnect - notify controller about VBUS session end * @gadget:the device whose VBUS supply is being described * * This call is used by a driver for an external transceiver (or GPIO) * that detects a VBUS power session ending. Common responses include * reversing everything done in usb_gadget_vbus_connect(). * * Returns zero on success, else negative errno. */ static inline int usb_gadget_vbus_disconnect(struct usb_gadget *gadget) { if (!gadget->ops->vbus_session) return -EOPNOTSUPP; return gadget->ops->vbus_session (gadget, 0); } /** * usb_gadget_connect - software-controlled connect to USB host * @gadget:the peripheral being connected * * Enables the D+ (or potentially D-) pullup. The host will start * enumerating this gadget when the pullup is active and a VBUS session * is active (the link is powered). This pullup is always enabled unless * usb_gadget_disconnect() has been used to disable it. * * Returns zero on success, else negative errno. */ static inline int usb_gadget_connect (struct usb_gadget *gadget) { if (!gadget->ops->pullup) return -EOPNOTSUPP; return gadget->ops->pullup (gadget, 1); } /** * usb_gadget_disconnect - software-controlled disconnect from USB host * @gadget:the peripheral being disconnected * * Disables the D+ (or potentially D-) pullup, which the host may see * as a disconnect (when a VBUS session is active). Not all systems * support software pullup controls. * * This routine may be used during the gadget driver bind() call to prevent * the peripheral from ever being visible to the USB host, unless later * usb_gadget_connect() is called. For example, user mode components may * need to be activated before the system can talk to hosts. * * Returns zero on success, else negative errno. */ static inline int usb_gadget_disconnect (struct usb_gadget *gadget) { if (!gadget->ops->pullup) return -EOPNOTSUPP; return gadget->ops->pullup (gadget, 0); } /*-------------------------------------------------------------------------*/ /** * struct usb_gadget_driver - driver for usb 'slave' devices * @function: String describing the gadget's function * @speed: Highest speed the driver handles. * @bind: Invoked when the driver is bound to a gadget, usually * after registering the driver. * At that point, ep0 is fully initialized, and ep_list holds * the currently-available endpoints. * Called in a context that permits sleeping. * @setup: Invoked for ep0 control requests that aren't handled by * the hardware level driver. Most calls must be handled by * the gadget driver, including descriptor and configuration * management. The 16 bit members of the setup data are in * USB byte order. Called in_interrupt; this may not sleep. Driver * queues a response to ep0, or returns negative to stall. * @disconnect: Invoked after all transfers have been stopped, * when the host is disconnected. May be called in_interrupt; this * may not sleep. Some devices can't detect disconnect, so this might * not be called except as part of controller shutdown. * @unbind: Invoked when the driver is unbound from a gadget, * usually from rmmod (after a disconnect is reported). * Called in a context that permits sleeping. * @suspend: Invoked on USB suspend. May be called in_interrupt. * @resume: Invoked on USB resume. May be called in_interrupt. * @driver: Driver model state for this driver. * * Devices are disabled till a gadget driver successfully bind()s, which * means the driver will handle setup() requests needed to enumerate (and * meet "chapter 9" requirements) then do some useful work. * * If gadget->is_otg is true, the gadget driver must provide an OTG * descriptor during enumeration, or else fail the bind() call. In such * cases, no USB traffic may flow until both bind() returns without * having called usb_gadget_disconnect(), and the USB host stack has * initialized. * * Drivers use hardware-specific knowledge to configure the usb hardware. * endpoint addressing is only one of several hardware characteristics that * are in descriptors the ep0 implementation returns from setup() calls. * * Except for ep0 implementation, most driver code shouldn't need change to * run on top of different usb controllers. It'll use endpoints set up by * that ep0 implementation. * * The usb controller driver handles a few standard usb requests. Those * include set_address, and feature flags for devices, interfaces, and * endpoints (the get_status, set_feature, and clear_feature requests). * * Accordingly, the driver's setup() callback must always implement all * get_descriptor requests, returning at least a device descriptor and * a configuration descriptor. Drivers must make sure the endpoint * descriptors match any hardware constraints. Some hardware also constrains * other descriptors. (The pxa250 allows only configurations 1, 2, or 3). * * The driver's setup() callback must also implement set_configuration, * and should also implement set_interface, get_configuration, and * get_interface. Setting a configuration (or interface) is where * endpoints should be activated or (config 0) shut down. * * (Note that only the default control endpoint is supported. Neither * hosts nor devices generally support control traffic except to ep0.) * * Most devices will ignore USB suspend/resume operations, and so will * not provide those callbacks. However, some may need to change modes * when the host is not longer directing those activities. For example, * local controls (buttons, dials, etc) may need to be re-enabled since * the (remote) host can't do that any longer; or an error state might * be cleared, to make the device behave identically whether or not * power is maintained. */ struct usb_gadget_driver { char *function; enum usb_device_speed speed; int (*bind)(struct usb_gadget *); void (*unbind)(struct usb_gadget *); int (*setup)(struct usb_gadget *, const struct usb_ctrlrequest *); void (*disconnect)(struct usb_gadget *); void (*suspend)(struct usb_gadget *); void (*resume)(struct usb_gadget *); // FIXME support safe rmmod struct device_driver driver; }; /*-------------------------------------------------------------------------*/ /* driver modules register and unregister, as usual. * these calls must be made in a context that can sleep. * * these will usually be implemented directly by the hardware-dependent * usb bus interface driver, which will only support a single driver. */ /** * usb_gadget_register_driver - register a gadget driver * @driver:the driver being registered * * Call this in your gadget driver's module initialization function, * to tell the underlying usb controller driver about your driver. * The driver's bind() function will be called to bind it to a * gadget. This function must be called in a context that can sleep. */ int usb_gadget_register_driver (struct usb_gadget_driver *driver); /** * usb_gadget_unregister_driver - unregister a gadget driver * @driver:the driver being unregistered * * Call this in your gadget driver's module cleanup function, * to tell the underlying usb controller that your driver is * going away. If the controller is connected to a USB host, * it will first disconnect(). The driver is also requested * to unbind() and clean up any device state, before this procedure * finally returns. * This function must be called in a context that can sleep. */ int usb_gadget_unregister_driver (struct usb_gadget_driver *driver); /*-------------------------------------------------------------------------*/ /* utility to simplify dealing with string descriptors */ /** * struct usb_string - wraps a C string and its USB id * @id:the (nonzero) ID for this string * @s:the string, in UTF-8 encoding * * If you're using usb_gadget_get_string(), use this to wrap a string * together with its ID. */ struct usb_string { u8 id; const char *s; }; /** * struct usb_gadget_strings - a set of USB strings in a given language * @language:identifies the strings' language (0x0409 for en-us) * @strings:array of strings with their ids * * If you're using usb_gadget_get_string(), use this to wrap all the * strings for a given language. */ struct usb_gadget_strings { u16 language; /* 0x0409 for en-us */ struct usb_string *strings; }; /* put descriptor for string with that id into buf (buflen >= 256) */ int usb_gadget_get_string (struct usb_gadget_strings *table, int id, u8 *buf); /*-------------------------------------------------------------------------*/ /* utility to simplify managing config descriptors */ /* write vector of descriptors into buffer */ int usb_descriptor_fillbuf(void *, unsigned, const struct usb_descriptor_header **); /* build config descriptor from single descriptor vector */ int usb_gadget_config_buf(const struct usb_config_descriptor *config, void *buf, unsigned buflen, const struct usb_descriptor_header **desc); /*-------------------------------------------------------------------------*/ /* utility wrapping a simple endpoint selection policy */ extern struct usb_ep *usb_ep_autoconfig (struct usb_gadget *, struct usb_endpoint_descriptor *) __init; extern void usb_ep_autoconfig_reset (struct usb_gadget *) __init; #endif /* __KERNEL__ */ #endif /* __LINUX_USB_GADGET_H */