882 lines
34 KiB
C
882 lines
34 KiB
C
/*
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* <linux/usb_gadget.h>
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*
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* We call the USB code inside a Linux-based peripheral device a "gadget"
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* driver, except for the hardware-specific bus glue. One USB host can
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* master many USB gadgets, but the gadgets are only slaved to one host.
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*
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*
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* (C) Copyright 2002-2004 by David Brownell
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* All Rights Reserved.
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*
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* This software is licensed under the GNU GPL version 2.
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*/
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#ifndef __LINUX_USB_GADGET_H
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#define __LINUX_USB_GADGET_H
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#ifdef __KERNEL__
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struct usb_ep;
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/**
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* struct usb_request - describes one i/o request
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* @buf: Buffer used for data. Always provide this; some controllers
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* only use PIO, or don't use DMA for some endpoints.
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* @dma: DMA address corresponding to 'buf'. If you don't set this
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* field, and the usb controller needs one, it is responsible
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* for mapping and unmapping the buffer.
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* @length: Length of that data
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* @no_interrupt: If true, hints that no completion irq is needed.
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* Helpful sometimes with deep request queues that are handled
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* directly by DMA controllers.
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* @zero: If true, when writing data, makes the last packet be "short"
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* by adding a zero length packet as needed;
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* @short_not_ok: When reading data, makes short packets be
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* treated as errors (queue stops advancing till cleanup).
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* @complete: Function called when request completes, so this request and
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* its buffer may be re-used.
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* Reads terminate with a short packet, or when the buffer fills,
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* whichever comes first. When writes terminate, some data bytes
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* will usually still be in flight (often in a hardware fifo).
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* Errors (for reads or writes) stop the queue from advancing
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* until the completion function returns, so that any transfers
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* invalidated by the error may first be dequeued.
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* @context: For use by the completion callback
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* @list: For use by the gadget driver.
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* @status: Reports completion code, zero or a negative errno.
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* Normally, faults block the transfer queue from advancing until
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* the completion callback returns.
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* Code "-ESHUTDOWN" indicates completion caused by device disconnect,
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* or when the driver disabled the endpoint.
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* @actual: Reports bytes transferred to/from the buffer. For reads (OUT
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* transfers) this may be less than the requested length. If the
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* short_not_ok flag is set, short reads are treated as errors
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* even when status otherwise indicates successful completion.
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* Note that for writes (IN transfers) some data bytes may still
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* reside in a device-side FIFO when the request is reported as
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* complete.
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*
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* These are allocated/freed through the endpoint they're used with. The
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* hardware's driver can add extra per-request data to the memory it returns,
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* which often avoids separate memory allocations (potential failures),
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* later when the request is queued.
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*
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* Request flags affect request handling, such as whether a zero length
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* packet is written (the "zero" flag), whether a short read should be
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* treated as an error (blocking request queue advance, the "short_not_ok"
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* flag), or hinting that an interrupt is not required (the "no_interrupt"
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* flag, for use with deep request queues).
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*
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* Bulk endpoints can use any size buffers, and can also be used for interrupt
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* transfers. interrupt-only endpoints can be much less functional.
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*/
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// NOTE this is analagous to 'struct urb' on the host side,
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// except that it's thinner and promotes more pre-allocation.
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struct usb_request {
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void *buf;
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unsigned length;
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dma_addr_t dma;
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unsigned no_interrupt:1;
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unsigned zero:1;
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unsigned short_not_ok:1;
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void (*complete)(struct usb_ep *ep,
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struct usb_request *req);
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void *context;
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struct list_head list;
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int status;
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unsigned actual;
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};
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/*-------------------------------------------------------------------------*/
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/* endpoint-specific parts of the api to the usb controller hardware.
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* unlike the urb model, (de)multiplexing layers are not required.
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* (so this api could slash overhead if used on the host side...)
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*
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* note that device side usb controllers commonly differ in how many
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* endpoints they support, as well as their capabilities.
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*/
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struct usb_ep_ops {
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int (*enable) (struct usb_ep *ep,
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const struct usb_endpoint_descriptor *desc);
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int (*disable) (struct usb_ep *ep);
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struct usb_request *(*alloc_request) (struct usb_ep *ep,
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gfp_t gfp_flags);
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void (*free_request) (struct usb_ep *ep, struct usb_request *req);
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void *(*alloc_buffer) (struct usb_ep *ep, unsigned bytes,
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dma_addr_t *dma, gfp_t gfp_flags);
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void (*free_buffer) (struct usb_ep *ep, void *buf, dma_addr_t dma,
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unsigned bytes);
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// NOTE: on 2.6, drivers may also use dma_map() and
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// dma_sync_single_*() to directly manage dma overhead.
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int (*queue) (struct usb_ep *ep, struct usb_request *req,
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gfp_t gfp_flags);
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int (*dequeue) (struct usb_ep *ep, struct usb_request *req);
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int (*set_halt) (struct usb_ep *ep, int value);
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int (*fifo_status) (struct usb_ep *ep);
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void (*fifo_flush) (struct usb_ep *ep);
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};
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/**
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* struct usb_ep - device side representation of USB endpoint
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* @name:identifier for the endpoint, such as "ep-a" or "ep9in-bulk"
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* @ops: Function pointers used to access hardware-specific operations.
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* @ep_list:the gadget's ep_list holds all of its endpoints
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* @maxpacket:The maximum packet size used on this endpoint. The initial
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* value can sometimes be reduced (hardware allowing), according to
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* the endpoint descriptor used to configure the endpoint.
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* @driver_data:for use by the gadget driver. all other fields are
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* read-only to gadget drivers.
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*
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* the bus controller driver lists all the general purpose endpoints in
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* gadget->ep_list. the control endpoint (gadget->ep0) is not in that list,
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* and is accessed only in response to a driver setup() callback.
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*/
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struct usb_ep {
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void *driver_data;
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const char *name;
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const struct usb_ep_ops *ops;
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struct list_head ep_list;
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unsigned maxpacket:16;
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};
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/*-------------------------------------------------------------------------*/
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/**
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* usb_ep_enable - configure endpoint, making it usable
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* @ep:the endpoint being configured. may not be the endpoint named "ep0".
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* drivers discover endpoints through the ep_list of a usb_gadget.
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* @desc:descriptor for desired behavior. caller guarantees this pointer
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* remains valid until the endpoint is disabled; the data byte order
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* is little-endian (usb-standard).
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*
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* when configurations are set, or when interface settings change, the driver
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* will enable or disable the relevant endpoints. while it is enabled, an
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* endpoint may be used for i/o until the driver receives a disconnect() from
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* the host or until the endpoint is disabled.
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*
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* the ep0 implementation (which calls this routine) must ensure that the
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* hardware capabilities of each endpoint match the descriptor provided
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* for it. for example, an endpoint named "ep2in-bulk" would be usable
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* for interrupt transfers as well as bulk, but it likely couldn't be used
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* for iso transfers or for endpoint 14. some endpoints are fully
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* configurable, with more generic names like "ep-a". (remember that for
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* USB, "in" means "towards the USB master".)
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*
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* returns zero, or a negative error code.
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*/
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static inline int
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usb_ep_enable (struct usb_ep *ep, const struct usb_endpoint_descriptor *desc)
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{
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return ep->ops->enable (ep, desc);
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}
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/**
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* usb_ep_disable - endpoint is no longer usable
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* @ep:the endpoint being unconfigured. may not be the endpoint named "ep0".
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*
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* no other task may be using this endpoint when this is called.
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* any pending and uncompleted requests will complete with status
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* indicating disconnect (-ESHUTDOWN) before this call returns.
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* gadget drivers must call usb_ep_enable() again before queueing
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* requests to the endpoint.
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*
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* returns zero, or a negative error code.
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*/
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static inline int
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usb_ep_disable (struct usb_ep *ep)
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{
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return ep->ops->disable (ep);
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}
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/**
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* usb_ep_alloc_request - allocate a request object to use with this endpoint
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* @ep:the endpoint to be used with with the request
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* @gfp_flags:GFP_* flags to use
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*
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* Request objects must be allocated with this call, since they normally
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* need controller-specific setup and may even need endpoint-specific
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* resources such as allocation of DMA descriptors.
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* Requests may be submitted with usb_ep_queue(), and receive a single
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* completion callback. Free requests with usb_ep_free_request(), when
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* they are no longer needed.
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*
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* Returns the request, or null if one could not be allocated.
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*/
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static inline struct usb_request *
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usb_ep_alloc_request (struct usb_ep *ep, gfp_t gfp_flags)
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{
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return ep->ops->alloc_request (ep, gfp_flags);
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}
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/**
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* usb_ep_free_request - frees a request object
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* @ep:the endpoint associated with the request
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* @req:the request being freed
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*
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* Reverses the effect of usb_ep_alloc_request().
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* Caller guarantees the request is not queued, and that it will
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* no longer be requeued (or otherwise used).
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*/
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static inline void
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usb_ep_free_request (struct usb_ep *ep, struct usb_request *req)
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{
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ep->ops->free_request (ep, req);
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}
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/**
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* usb_ep_alloc_buffer - allocate an I/O buffer
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* @ep:the endpoint associated with the buffer
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* @len:length of the desired buffer
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* @dma:pointer to the buffer's DMA address; must be valid
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* @gfp_flags:GFP_* flags to use
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*
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* Returns a new buffer, or null if one could not be allocated.
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* The buffer is suitably aligned for dma, if that endpoint uses DMA,
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* and the caller won't have to care about dma-inconsistency
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* or any hidden "bounce buffer" mechanism. No additional per-request
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* DMA mapping will be required for such buffers.
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* Free it later with usb_ep_free_buffer().
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*
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* You don't need to use this call to allocate I/O buffers unless you
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* want to make sure drivers don't incur costs for such "bounce buffer"
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* copies or per-request DMA mappings.
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*/
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static inline void *
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usb_ep_alloc_buffer (struct usb_ep *ep, unsigned len, dma_addr_t *dma,
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gfp_t gfp_flags)
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{
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return ep->ops->alloc_buffer (ep, len, dma, gfp_flags);
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}
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/**
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* usb_ep_free_buffer - frees an i/o buffer
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* @ep:the endpoint associated with the buffer
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* @buf:CPU view address of the buffer
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* @dma:the buffer's DMA address
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* @len:length of the buffer
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*
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* reverses the effect of usb_ep_alloc_buffer().
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* caller guarantees the buffer will no longer be accessed
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*/
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static inline void
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usb_ep_free_buffer (struct usb_ep *ep, void *buf, dma_addr_t dma, unsigned len)
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{
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ep->ops->free_buffer (ep, buf, dma, len);
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}
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/**
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* usb_ep_queue - queues (submits) an I/O request to an endpoint.
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* @ep:the endpoint associated with the request
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* @req:the request being submitted
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* @gfp_flags: GFP_* flags to use in case the lower level driver couldn't
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* pre-allocate all necessary memory with the request.
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*
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* This tells the device controller to perform the specified request through
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* that endpoint (reading or writing a buffer). When the request completes,
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* including being canceled by usb_ep_dequeue(), the request's completion
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* routine is called to return the request to the driver. Any endpoint
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* (except control endpoints like ep0) may have more than one transfer
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* request queued; they complete in FIFO order. Once a gadget driver
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* submits a request, that request may not be examined or modified until it
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* is given back to that driver through the completion callback.
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*
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* Each request is turned into one or more packets. The controller driver
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* never merges adjacent requests into the same packet. OUT transfers
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* will sometimes use data that's already buffered in the hardware.
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* Drivers can rely on the fact that the first byte of the request's buffer
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* always corresponds to the first byte of some USB packet, for both
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* IN and OUT transfers.
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*
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* Bulk endpoints can queue any amount of data; the transfer is packetized
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* automatically. The last packet will be short if the request doesn't fill it
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* out completely. Zero length packets (ZLPs) should be avoided in portable
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* protocols since not all usb hardware can successfully handle zero length
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* packets. (ZLPs may be explicitly written, and may be implicitly written if
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* the request 'zero' flag is set.) Bulk endpoints may also be used
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* for interrupt transfers; but the reverse is not true, and some endpoints
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* won't support every interrupt transfer. (Such as 768 byte packets.)
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*
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* Interrupt-only endpoints are less functional than bulk endpoints, for
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* example by not supporting queueing or not handling buffers that are
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* larger than the endpoint's maxpacket size. They may also treat data
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* toggle differently.
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*
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* Control endpoints ... after getting a setup() callback, the driver queues
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* one response (even if it would be zero length). That enables the
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* status ack, after transfering data as specified in the response. Setup
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* functions may return negative error codes to generate protocol stalls.
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* (Note that some USB device controllers disallow protocol stall responses
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* in some cases.) When control responses are deferred (the response is
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* written after the setup callback returns), then usb_ep_set_halt() may be
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* used on ep0 to trigger protocol stalls.
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*
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* For periodic endpoints, like interrupt or isochronous ones, the usb host
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* arranges to poll once per interval, and the gadget driver usually will
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* have queued some data to transfer at that time.
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*
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* Returns zero, or a negative error code. Endpoints that are not enabled
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* report errors; errors will also be
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* reported when the usb peripheral is disconnected.
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*/
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static inline int
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usb_ep_queue (struct usb_ep *ep, struct usb_request *req, gfp_t gfp_flags)
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{
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return ep->ops->queue (ep, req, gfp_flags);
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}
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/**
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* usb_ep_dequeue - dequeues (cancels, unlinks) an I/O request from an endpoint
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* @ep:the endpoint associated with the request
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* @req:the request being canceled
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*
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* if the request is still active on the endpoint, it is dequeued and its
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* completion routine is called (with status -ECONNRESET); else a negative
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* error code is returned.
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*
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* note that some hardware can't clear out write fifos (to unlink the request
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* at the head of the queue) except as part of disconnecting from usb. such
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* restrictions prevent drivers from supporting configuration changes,
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* even to configuration zero (a "chapter 9" requirement).
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*/
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static inline int usb_ep_dequeue (struct usb_ep *ep, struct usb_request *req)
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{
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return ep->ops->dequeue (ep, req);
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}
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/**
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* usb_ep_set_halt - sets the endpoint halt feature.
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* @ep: the non-isochronous endpoint being stalled
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*
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* Use this to stall an endpoint, perhaps as an error report.
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* Except for control endpoints,
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* the endpoint stays halted (will not stream any data) until the host
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* clears this feature; drivers may need to empty the endpoint's request
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* queue first, to make sure no inappropriate transfers happen.
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*
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* Note that while an endpoint CLEAR_FEATURE will be invisible to the
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* gadget driver, a SET_INTERFACE will not be. To reset endpoints for the
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* current altsetting, see usb_ep_clear_halt(). When switching altsettings,
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* it's simplest to use usb_ep_enable() or usb_ep_disable() for the endpoints.
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*
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* Returns zero, or a negative error code. On success, this call sets
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* underlying hardware state that blocks data transfers.
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* Attempts to halt IN endpoints will fail (returning -EAGAIN) if any
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* transfer requests are still queued, or if the controller hardware
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* (usually a FIFO) still holds bytes that the host hasn't collected.
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*/
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static inline int
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usb_ep_set_halt (struct usb_ep *ep)
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{
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return ep->ops->set_halt (ep, 1);
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}
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/**
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* usb_ep_clear_halt - clears endpoint halt, and resets toggle
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* @ep:the bulk or interrupt endpoint being reset
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*
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* Use this when responding to the standard usb "set interface" request,
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* for endpoints that aren't reconfigured, after clearing any other state
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* in the endpoint's i/o queue.
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*
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* Returns zero, or a negative error code. On success, this call clears
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* the underlying hardware state reflecting endpoint halt and data toggle.
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* Note that some hardware can't support this request (like pxa2xx_udc),
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* and accordingly can't correctly implement interface altsettings.
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*/
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static inline int
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usb_ep_clear_halt (struct usb_ep *ep)
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{
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return ep->ops->set_halt (ep, 0);
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}
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/**
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* usb_ep_fifo_status - returns number of bytes in fifo, or error
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* @ep: the endpoint whose fifo status is being checked.
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*
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* FIFO endpoints may have "unclaimed data" in them in certain cases,
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* such as after aborted transfers. Hosts may not have collected all
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* the IN data written by the gadget driver (and reported by a request
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* completion). The gadget driver may not have collected all the data
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* written OUT to it by the host. Drivers that need precise handling for
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* fault reporting or recovery may need to use this call.
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*
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* This returns the number of such bytes in the fifo, or a negative
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* errno if the endpoint doesn't use a FIFO or doesn't support such
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* precise handling.
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*/
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static inline int
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usb_ep_fifo_status (struct usb_ep *ep)
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{
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if (ep->ops->fifo_status)
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return ep->ops->fifo_status (ep);
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else
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return -EOPNOTSUPP;
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}
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/**
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* usb_ep_fifo_flush - flushes contents of a fifo
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* @ep: the endpoint whose fifo is being flushed.
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*
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* This call may be used to flush the "unclaimed data" that may exist in
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* an endpoint fifo after abnormal transaction terminations. The call
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* must never be used except when endpoint is not being used for any
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* protocol translation.
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*/
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static inline void
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usb_ep_fifo_flush (struct usb_ep *ep)
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{
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if (ep->ops->fifo_flush)
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ep->ops->fifo_flush (ep);
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}
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/*-------------------------------------------------------------------------*/
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struct usb_gadget;
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/* the rest of the api to the controller hardware: device operations,
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* which don't involve endpoints (or i/o).
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*/
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struct usb_gadget_ops {
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int (*get_frame)(struct usb_gadget *);
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int (*wakeup)(struct usb_gadget *);
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int (*set_selfpowered) (struct usb_gadget *, int is_selfpowered);
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int (*vbus_session) (struct usb_gadget *, int is_active);
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int (*vbus_draw) (struct usb_gadget *, unsigned mA);
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int (*pullup) (struct usb_gadget *, int is_on);
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int (*ioctl)(struct usb_gadget *,
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unsigned code, unsigned long param);
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};
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/**
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* struct usb_gadget - represents a usb slave device
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* @ops: Function pointers used to access hardware-specific operations.
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* @ep0: Endpoint zero, used when reading or writing responses to
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* driver setup() requests
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* @ep_list: List of other endpoints supported by the device.
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* @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 before this registration call returns. It's expected that
|
|
* the bind() functions will be in init sections.
|
|
* 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. It's expected that the unbind() functions
|
|
* will in in exit sections, so may not be linked in some kernels.
|
|
* 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 */
|