Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | /* |
| 2 | * <linux/usb_gadget.h> |
| 3 | * |
| 4 | * We call the USB code inside a Linux-based peripheral device a "gadget" |
| 5 | * driver, except for the hardware-specific bus glue. One USB host can |
| 6 | * master many USB gadgets, but the gadgets are only slaved to one host. |
| 7 | * |
| 8 | * |
| 9 | * (C) Copyright 2002-2004 by David Brownell |
| 10 | * All Rights Reserved. |
| 11 | * |
| 12 | * This software is licensed under the GNU GPL version 2. |
| 13 | */ |
| 14 | |
| 15 | #ifndef __LINUX_USB_GADGET_H |
| 16 | #define __LINUX_USB_GADGET_H |
| 17 | |
| 18 | #ifdef __KERNEL__ |
| 19 | |
| 20 | struct usb_ep; |
| 21 | |
| 22 | /** |
| 23 | * struct usb_request - describes one i/o request |
| 24 | * @buf: Buffer used for data. Always provide this; some controllers |
| 25 | * only use PIO, or don't use DMA for some endpoints. |
| 26 | * @dma: DMA address corresponding to 'buf'. If you don't set this |
| 27 | * field, and the usb controller needs one, it is responsible |
| 28 | * for mapping and unmapping the buffer. |
| 29 | * @length: Length of that data |
| 30 | * @no_interrupt: If true, hints that no completion irq is needed. |
| 31 | * Helpful sometimes with deep request queues that are handled |
| 32 | * directly by DMA controllers. |
| 33 | * @zero: If true, when writing data, makes the last packet be "short" |
| 34 | * by adding a zero length packet as needed; |
| 35 | * @short_not_ok: When reading data, makes short packets be |
| 36 | * treated as errors (queue stops advancing till cleanup). |
| 37 | * @complete: Function called when request completes, so this request and |
| 38 | * its buffer may be re-used. |
| 39 | * Reads terminate with a short packet, or when the buffer fills, |
| 40 | * whichever comes first. When writes terminate, some data bytes |
| 41 | * will usually still be in flight (often in a hardware fifo). |
| 42 | * Errors (for reads or writes) stop the queue from advancing |
| 43 | * until the completion function returns, so that any transfers |
| 44 | * invalidated by the error may first be dequeued. |
| 45 | * @context: For use by the completion callback |
| 46 | * @list: For use by the gadget driver. |
| 47 | * @status: Reports completion code, zero or a negative errno. |
| 48 | * Normally, faults block the transfer queue from advancing until |
| 49 | * the completion callback returns. |
| 50 | * Code "-ESHUTDOWN" indicates completion caused by device disconnect, |
| 51 | * or when the driver disabled the endpoint. |
| 52 | * @actual: Reports bytes transferred to/from the buffer. For reads (OUT |
| 53 | * transfers) this may be less than the requested length. If the |
| 54 | * short_not_ok flag is set, short reads are treated as errors |
| 55 | * even when status otherwise indicates successful completion. |
| 56 | * Note that for writes (IN transfers) some data bytes may still |
| 57 | * reside in a device-side FIFO when the request is reported as |
| 58 | * complete. |
| 59 | * |
| 60 | * These are allocated/freed through the endpoint they're used with. The |
| 61 | * hardware's driver can add extra per-request data to the memory it returns, |
| 62 | * which often avoids separate memory allocations (potential failures), |
| 63 | * later when the request is queued. |
| 64 | * |
| 65 | * Request flags affect request handling, such as whether a zero length |
| 66 | * packet is written (the "zero" flag), whether a short read should be |
| 67 | * treated as an error (blocking request queue advance, the "short_not_ok" |
| 68 | * flag), or hinting that an interrupt is not required (the "no_interrupt" |
| 69 | * flag, for use with deep request queues). |
| 70 | * |
| 71 | * Bulk endpoints can use any size buffers, and can also be used for interrupt |
| 72 | * transfers. interrupt-only endpoints can be much less functional. |
| 73 | */ |
| 74 | // NOTE this is analagous to 'struct urb' on the host side, |
| 75 | // except that it's thinner and promotes more pre-allocation. |
| 76 | |
| 77 | struct usb_request { |
| 78 | void *buf; |
| 79 | unsigned length; |
| 80 | dma_addr_t dma; |
| 81 | |
| 82 | unsigned no_interrupt:1; |
| 83 | unsigned zero:1; |
| 84 | unsigned short_not_ok:1; |
| 85 | |
| 86 | void (*complete)(struct usb_ep *ep, |
| 87 | struct usb_request *req); |
| 88 | void *context; |
| 89 | struct list_head list; |
| 90 | |
| 91 | int status; |
| 92 | unsigned actual; |
| 93 | }; |
| 94 | |
| 95 | /*-------------------------------------------------------------------------*/ |
| 96 | |
| 97 | /* endpoint-specific parts of the api to the usb controller hardware. |
| 98 | * unlike the urb model, (de)multiplexing layers are not required. |
| 99 | * (so this api could slash overhead if used on the host side...) |
| 100 | * |
| 101 | * note that device side usb controllers commonly differ in how many |
| 102 | * endpoints they support, as well as their capabilities. |
| 103 | */ |
| 104 | struct usb_ep_ops { |
| 105 | int (*enable) (struct usb_ep *ep, |
| 106 | const struct usb_endpoint_descriptor *desc); |
| 107 | int (*disable) (struct usb_ep *ep); |
| 108 | |
| 109 | struct usb_request *(*alloc_request) (struct usb_ep *ep, |
Olav Kongas | 5db539e | 2005-06-23 20:25:36 +0300 | [diff] [blame] | 110 | unsigned gfp_flags); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 111 | void (*free_request) (struct usb_ep *ep, struct usb_request *req); |
| 112 | |
| 113 | void *(*alloc_buffer) (struct usb_ep *ep, unsigned bytes, |
Olav Kongas | 5db539e | 2005-06-23 20:25:36 +0300 | [diff] [blame] | 114 | dma_addr_t *dma, unsigned gfp_flags); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 115 | void (*free_buffer) (struct usb_ep *ep, void *buf, dma_addr_t dma, |
| 116 | unsigned bytes); |
| 117 | // NOTE: on 2.6, drivers may also use dma_map() and |
| 118 | // dma_sync_single_*() to directly manage dma overhead. |
| 119 | |
| 120 | int (*queue) (struct usb_ep *ep, struct usb_request *req, |
Olav Kongas | 5db539e | 2005-06-23 20:25:36 +0300 | [diff] [blame] | 121 | unsigned gfp_flags); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 122 | int (*dequeue) (struct usb_ep *ep, struct usb_request *req); |
| 123 | |
| 124 | int (*set_halt) (struct usb_ep *ep, int value); |
| 125 | int (*fifo_status) (struct usb_ep *ep); |
| 126 | void (*fifo_flush) (struct usb_ep *ep); |
| 127 | }; |
| 128 | |
| 129 | /** |
| 130 | * struct usb_ep - device side representation of USB endpoint |
| 131 | * @name:identifier for the endpoint, such as "ep-a" or "ep9in-bulk" |
| 132 | * @ops: Function pointers used to access hardware-specific operations. |
| 133 | * @ep_list:the gadget's ep_list holds all of its endpoints |
| 134 | * @maxpacket:The maximum packet size used on this endpoint. The initial |
| 135 | * value can sometimes be reduced (hardware allowing), according to |
| 136 | * the endpoint descriptor used to configure the endpoint. |
| 137 | * @driver_data:for use by the gadget driver. all other fields are |
| 138 | * read-only to gadget drivers. |
| 139 | * |
| 140 | * the bus controller driver lists all the general purpose endpoints in |
| 141 | * gadget->ep_list. the control endpoint (gadget->ep0) is not in that list, |
| 142 | * and is accessed only in response to a driver setup() callback. |
| 143 | */ |
| 144 | struct usb_ep { |
| 145 | void *driver_data; |
| 146 | |
| 147 | const char *name; |
| 148 | const struct usb_ep_ops *ops; |
| 149 | struct list_head ep_list; |
| 150 | unsigned maxpacket:16; |
| 151 | }; |
| 152 | |
| 153 | /*-------------------------------------------------------------------------*/ |
| 154 | |
| 155 | /** |
| 156 | * usb_ep_enable - configure endpoint, making it usable |
| 157 | * @ep:the endpoint being configured. may not be the endpoint named "ep0". |
| 158 | * drivers discover endpoints through the ep_list of a usb_gadget. |
| 159 | * @desc:descriptor for desired behavior. caller guarantees this pointer |
| 160 | * remains valid until the endpoint is disabled; the data byte order |
| 161 | * is little-endian (usb-standard). |
| 162 | * |
| 163 | * when configurations are set, or when interface settings change, the driver |
| 164 | * will enable or disable the relevant endpoints. while it is enabled, an |
| 165 | * endpoint may be used for i/o until the driver receives a disconnect() from |
| 166 | * the host or until the endpoint is disabled. |
| 167 | * |
| 168 | * the ep0 implementation (which calls this routine) must ensure that the |
| 169 | * hardware capabilities of each endpoint match the descriptor provided |
| 170 | * for it. for example, an endpoint named "ep2in-bulk" would be usable |
| 171 | * for interrupt transfers as well as bulk, but it likely couldn't be used |
| 172 | * for iso transfers or for endpoint 14. some endpoints are fully |
| 173 | * configurable, with more generic names like "ep-a". (remember that for |
| 174 | * USB, "in" means "towards the USB master".) |
| 175 | * |
| 176 | * returns zero, or a negative error code. |
| 177 | */ |
| 178 | static inline int |
| 179 | usb_ep_enable (struct usb_ep *ep, const struct usb_endpoint_descriptor *desc) |
| 180 | { |
| 181 | return ep->ops->enable (ep, desc); |
| 182 | } |
| 183 | |
| 184 | /** |
| 185 | * usb_ep_disable - endpoint is no longer usable |
| 186 | * @ep:the endpoint being unconfigured. may not be the endpoint named "ep0". |
| 187 | * |
| 188 | * no other task may be using this endpoint when this is called. |
| 189 | * any pending and uncompleted requests will complete with status |
| 190 | * indicating disconnect (-ESHUTDOWN) before this call returns. |
| 191 | * gadget drivers must call usb_ep_enable() again before queueing |
| 192 | * requests to the endpoint. |
| 193 | * |
| 194 | * returns zero, or a negative error code. |
| 195 | */ |
| 196 | static inline int |
| 197 | usb_ep_disable (struct usb_ep *ep) |
| 198 | { |
| 199 | return ep->ops->disable (ep); |
| 200 | } |
| 201 | |
| 202 | /** |
| 203 | * usb_ep_alloc_request - allocate a request object to use with this endpoint |
| 204 | * @ep:the endpoint to be used with with the request |
| 205 | * @gfp_flags:GFP_* flags to use |
| 206 | * |
| 207 | * Request objects must be allocated with this call, since they normally |
| 208 | * need controller-specific setup and may even need endpoint-specific |
| 209 | * resources such as allocation of DMA descriptors. |
| 210 | * Requests may be submitted with usb_ep_queue(), and receive a single |
| 211 | * completion callback. Free requests with usb_ep_free_request(), when |
| 212 | * they are no longer needed. |
| 213 | * |
| 214 | * Returns the request, or null if one could not be allocated. |
| 215 | */ |
| 216 | static inline struct usb_request * |
Olav Kongas | 5db539e | 2005-06-23 20:25:36 +0300 | [diff] [blame] | 217 | usb_ep_alloc_request (struct usb_ep *ep, unsigned gfp_flags) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 218 | { |
| 219 | return ep->ops->alloc_request (ep, gfp_flags); |
| 220 | } |
| 221 | |
| 222 | /** |
| 223 | * usb_ep_free_request - frees a request object |
| 224 | * @ep:the endpoint associated with the request |
| 225 | * @req:the request being freed |
| 226 | * |
| 227 | * Reverses the effect of usb_ep_alloc_request(). |
| 228 | * Caller guarantees the request is not queued, and that it will |
| 229 | * no longer be requeued (or otherwise used). |
| 230 | */ |
| 231 | static inline void |
| 232 | usb_ep_free_request (struct usb_ep *ep, struct usb_request *req) |
| 233 | { |
| 234 | ep->ops->free_request (ep, req); |
| 235 | } |
| 236 | |
| 237 | /** |
| 238 | * usb_ep_alloc_buffer - allocate an I/O buffer |
| 239 | * @ep:the endpoint associated with the buffer |
| 240 | * @len:length of the desired buffer |
| 241 | * @dma:pointer to the buffer's DMA address; must be valid |
| 242 | * @gfp_flags:GFP_* flags to use |
| 243 | * |
| 244 | * Returns a new buffer, or null if one could not be allocated. |
| 245 | * The buffer is suitably aligned for dma, if that endpoint uses DMA, |
| 246 | * and the caller won't have to care about dma-inconsistency |
| 247 | * or any hidden "bounce buffer" mechanism. No additional per-request |
| 248 | * DMA mapping will be required for such buffers. |
| 249 | * Free it later with usb_ep_free_buffer(). |
| 250 | * |
| 251 | * You don't need to use this call to allocate I/O buffers unless you |
| 252 | * want to make sure drivers don't incur costs for such "bounce buffer" |
| 253 | * copies or per-request DMA mappings. |
| 254 | */ |
| 255 | static inline void * |
| 256 | usb_ep_alloc_buffer (struct usb_ep *ep, unsigned len, dma_addr_t *dma, |
Olav Kongas | 5db539e | 2005-06-23 20:25:36 +0300 | [diff] [blame] | 257 | unsigned gfp_flags) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 258 | { |
| 259 | return ep->ops->alloc_buffer (ep, len, dma, gfp_flags); |
| 260 | } |
| 261 | |
| 262 | /** |
| 263 | * usb_ep_free_buffer - frees an i/o buffer |
| 264 | * @ep:the endpoint associated with the buffer |
| 265 | * @buf:CPU view address of the buffer |
| 266 | * @dma:the buffer's DMA address |
| 267 | * @len:length of the buffer |
| 268 | * |
| 269 | * reverses the effect of usb_ep_alloc_buffer(). |
| 270 | * caller guarantees the buffer will no longer be accessed |
| 271 | */ |
| 272 | static inline void |
| 273 | usb_ep_free_buffer (struct usb_ep *ep, void *buf, dma_addr_t dma, unsigned len) |
| 274 | { |
| 275 | ep->ops->free_buffer (ep, buf, dma, len); |
| 276 | } |
| 277 | |
| 278 | /** |
| 279 | * usb_ep_queue - queues (submits) an I/O request to an endpoint. |
| 280 | * @ep:the endpoint associated with the request |
| 281 | * @req:the request being submitted |
| 282 | * @gfp_flags: GFP_* flags to use in case the lower level driver couldn't |
| 283 | * pre-allocate all necessary memory with the request. |
| 284 | * |
| 285 | * This tells the device controller to perform the specified request through |
| 286 | * that endpoint (reading or writing a buffer). When the request completes, |
| 287 | * including being canceled by usb_ep_dequeue(), the request's completion |
| 288 | * routine is called to return the request to the driver. Any endpoint |
| 289 | * (except control endpoints like ep0) may have more than one transfer |
| 290 | * request queued; they complete in FIFO order. Once a gadget driver |
| 291 | * submits a request, that request may not be examined or modified until it |
| 292 | * is given back to that driver through the completion callback. |
| 293 | * |
| 294 | * Each request is turned into one or more packets. The controller driver |
| 295 | * never merges adjacent requests into the same packet. OUT transfers |
| 296 | * will sometimes use data that's already buffered in the hardware. |
| 297 | * Drivers can rely on the fact that the first byte of the request's buffer |
| 298 | * always corresponds to the first byte of some USB packet, for both |
| 299 | * IN and OUT transfers. |
| 300 | * |
| 301 | * Bulk endpoints can queue any amount of data; the transfer is packetized |
| 302 | * automatically. The last packet will be short if the request doesn't fill it |
| 303 | * out completely. Zero length packets (ZLPs) should be avoided in portable |
| 304 | * protocols since not all usb hardware can successfully handle zero length |
| 305 | * packets. (ZLPs may be explicitly written, and may be implicitly written if |
| 306 | * the request 'zero' flag is set.) Bulk endpoints may also be used |
| 307 | * for interrupt transfers; but the reverse is not true, and some endpoints |
| 308 | * won't support every interrupt transfer. (Such as 768 byte packets.) |
| 309 | * |
| 310 | * Interrupt-only endpoints are less functional than bulk endpoints, for |
| 311 | * example by not supporting queueing or not handling buffers that are |
| 312 | * larger than the endpoint's maxpacket size. They may also treat data |
| 313 | * toggle differently. |
| 314 | * |
| 315 | * Control endpoints ... after getting a setup() callback, the driver queues |
| 316 | * one response (even if it would be zero length). That enables the |
| 317 | * status ack, after transfering data as specified in the response. Setup |
| 318 | * functions may return negative error codes to generate protocol stalls. |
| 319 | * (Note that some USB device controllers disallow protocol stall responses |
| 320 | * in some cases.) When control responses are deferred (the response is |
| 321 | * written after the setup callback returns), then usb_ep_set_halt() may be |
| 322 | * used on ep0 to trigger protocol stalls. |
| 323 | * |
| 324 | * For periodic endpoints, like interrupt or isochronous ones, the usb host |
| 325 | * arranges to poll once per interval, and the gadget driver usually will |
| 326 | * have queued some data to transfer at that time. |
| 327 | * |
| 328 | * Returns zero, or a negative error code. Endpoints that are not enabled |
| 329 | * report errors; errors will also be |
| 330 | * reported when the usb peripheral is disconnected. |
| 331 | */ |
| 332 | static inline int |
Olav Kongas | 5db539e | 2005-06-23 20:25:36 +0300 | [diff] [blame] | 333 | usb_ep_queue (struct usb_ep *ep, struct usb_request *req, unsigned gfp_flags) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 334 | { |
| 335 | return ep->ops->queue (ep, req, gfp_flags); |
| 336 | } |
| 337 | |
| 338 | /** |
| 339 | * usb_ep_dequeue - dequeues (cancels, unlinks) an I/O request from an endpoint |
| 340 | * @ep:the endpoint associated with the request |
| 341 | * @req:the request being canceled |
| 342 | * |
| 343 | * if the request is still active on the endpoint, it is dequeued and its |
| 344 | * completion routine is called (with status -ECONNRESET); else a negative |
| 345 | * error code is returned. |
| 346 | * |
| 347 | * note that some hardware can't clear out write fifos (to unlink the request |
| 348 | * at the head of the queue) except as part of disconnecting from usb. such |
| 349 | * restrictions prevent drivers from supporting configuration changes, |
| 350 | * even to configuration zero (a "chapter 9" requirement). |
| 351 | */ |
| 352 | static inline int usb_ep_dequeue (struct usb_ep *ep, struct usb_request *req) |
| 353 | { |
| 354 | return ep->ops->dequeue (ep, req); |
| 355 | } |
| 356 | |
| 357 | /** |
| 358 | * usb_ep_set_halt - sets the endpoint halt feature. |
| 359 | * @ep: the non-isochronous endpoint being stalled |
| 360 | * |
| 361 | * Use this to stall an endpoint, perhaps as an error report. |
| 362 | * Except for control endpoints, |
| 363 | * the endpoint stays halted (will not stream any data) until the host |
| 364 | * clears this feature; drivers may need to empty the endpoint's request |
| 365 | * queue first, to make sure no inappropriate transfers happen. |
| 366 | * |
| 367 | * Note that while an endpoint CLEAR_FEATURE will be invisible to the |
| 368 | * gadget driver, a SET_INTERFACE will not be. To reset endpoints for the |
| 369 | * current altsetting, see usb_ep_clear_halt(). When switching altsettings, |
| 370 | * it's simplest to use usb_ep_enable() or usb_ep_disable() for the endpoints. |
| 371 | * |
| 372 | * Returns zero, or a negative error code. On success, this call sets |
| 373 | * underlying hardware state that blocks data transfers. |
| 374 | * Attempts to halt IN endpoints will fail (returning -EAGAIN) if any |
| 375 | * transfer requests are still queued, or if the controller hardware |
| 376 | * (usually a FIFO) still holds bytes that the host hasn't collected. |
| 377 | */ |
| 378 | static inline int |
| 379 | usb_ep_set_halt (struct usb_ep *ep) |
| 380 | { |
| 381 | return ep->ops->set_halt (ep, 1); |
| 382 | } |
| 383 | |
| 384 | /** |
| 385 | * usb_ep_clear_halt - clears endpoint halt, and resets toggle |
| 386 | * @ep:the bulk or interrupt endpoint being reset |
| 387 | * |
| 388 | * Use this when responding to the standard usb "set interface" request, |
| 389 | * for endpoints that aren't reconfigured, after clearing any other state |
| 390 | * in the endpoint's i/o queue. |
| 391 | * |
| 392 | * Returns zero, or a negative error code. On success, this call clears |
| 393 | * the underlying hardware state reflecting endpoint halt and data toggle. |
| 394 | * Note that some hardware can't support this request (like pxa2xx_udc), |
| 395 | * and accordingly can't correctly implement interface altsettings. |
| 396 | */ |
| 397 | static inline int |
| 398 | usb_ep_clear_halt (struct usb_ep *ep) |
| 399 | { |
| 400 | return ep->ops->set_halt (ep, 0); |
| 401 | } |
| 402 | |
| 403 | /** |
| 404 | * usb_ep_fifo_status - returns number of bytes in fifo, or error |
| 405 | * @ep: the endpoint whose fifo status is being checked. |
| 406 | * |
| 407 | * FIFO endpoints may have "unclaimed data" in them in certain cases, |
| 408 | * such as after aborted transfers. Hosts may not have collected all |
| 409 | * the IN data written by the gadget driver (and reported by a request |
| 410 | * completion). The gadget driver may not have collected all the data |
| 411 | * written OUT to it by the host. Drivers that need precise handling for |
| 412 | * fault reporting or recovery may need to use this call. |
| 413 | * |
| 414 | * This returns the number of such bytes in the fifo, or a negative |
| 415 | * errno if the endpoint doesn't use a FIFO or doesn't support such |
| 416 | * precise handling. |
| 417 | */ |
| 418 | static inline int |
| 419 | usb_ep_fifo_status (struct usb_ep *ep) |
| 420 | { |
| 421 | if (ep->ops->fifo_status) |
| 422 | return ep->ops->fifo_status (ep); |
| 423 | else |
| 424 | return -EOPNOTSUPP; |
| 425 | } |
| 426 | |
| 427 | /** |
| 428 | * usb_ep_fifo_flush - flushes contents of a fifo |
| 429 | * @ep: the endpoint whose fifo is being flushed. |
| 430 | * |
| 431 | * This call may be used to flush the "unclaimed data" that may exist in |
| 432 | * an endpoint fifo after abnormal transaction terminations. The call |
| 433 | * must never be used except when endpoint is not being used for any |
| 434 | * protocol translation. |
| 435 | */ |
| 436 | static inline void |
| 437 | usb_ep_fifo_flush (struct usb_ep *ep) |
| 438 | { |
| 439 | if (ep->ops->fifo_flush) |
| 440 | ep->ops->fifo_flush (ep); |
| 441 | } |
| 442 | |
| 443 | |
| 444 | /*-------------------------------------------------------------------------*/ |
| 445 | |
| 446 | struct usb_gadget; |
| 447 | |
| 448 | /* the rest of the api to the controller hardware: device operations, |
| 449 | * which don't involve endpoints (or i/o). |
| 450 | */ |
| 451 | struct usb_gadget_ops { |
| 452 | int (*get_frame)(struct usb_gadget *); |
| 453 | int (*wakeup)(struct usb_gadget *); |
| 454 | int (*set_selfpowered) (struct usb_gadget *, int is_selfpowered); |
| 455 | int (*vbus_session) (struct usb_gadget *, int is_active); |
| 456 | int (*vbus_draw) (struct usb_gadget *, unsigned mA); |
| 457 | int (*pullup) (struct usb_gadget *, int is_on); |
| 458 | int (*ioctl)(struct usb_gadget *, |
| 459 | unsigned code, unsigned long param); |
| 460 | }; |
| 461 | |
| 462 | /** |
| 463 | * struct usb_gadget - represents a usb slave device |
| 464 | * @ops: Function pointers used to access hardware-specific operations. |
| 465 | * @ep0: Endpoint zero, used when reading or writing responses to |
| 466 | * driver setup() requests |
| 467 | * @ep_list: List of other endpoints supported by the device. |
| 468 | * @speed: Speed of current connection to USB host. |
| 469 | * @is_dualspeed: True if the controller supports both high and full speed |
| 470 | * operation. If it does, the gadget driver must also support both. |
| 471 | * @is_otg: True if the USB device port uses a Mini-AB jack, so that the |
| 472 | * gadget driver must provide a USB OTG descriptor. |
| 473 | * @is_a_peripheral: False unless is_otg, the "A" end of a USB cable |
| 474 | * is in the Mini-AB jack, and HNP has been used to switch roles |
| 475 | * so that the "A" device currently acts as A-Peripheral, not A-Host. |
| 476 | * @a_hnp_support: OTG device feature flag, indicating that the A-Host |
| 477 | * supports HNP at this port. |
| 478 | * @a_alt_hnp_support: OTG device feature flag, indicating that the A-Host |
| 479 | * only supports HNP on a different root port. |
| 480 | * @b_hnp_enable: OTG device feature flag, indicating that the A-Host |
| 481 | * enabled HNP support. |
| 482 | * @name: Identifies the controller hardware type. Used in diagnostics |
| 483 | * and sometimes configuration. |
| 484 | * @dev: Driver model state for this abstract device. |
| 485 | * |
| 486 | * Gadgets have a mostly-portable "gadget driver" implementing device |
| 487 | * functions, handling all usb configurations and interfaces. Gadget |
| 488 | * drivers talk to hardware-specific code indirectly, through ops vectors. |
| 489 | * That insulates the gadget driver from hardware details, and packages |
| 490 | * the hardware endpoints through generic i/o queues. The "usb_gadget" |
| 491 | * and "usb_ep" interfaces provide that insulation from the hardware. |
| 492 | * |
| 493 | * Except for the driver data, all fields in this structure are |
| 494 | * read-only to the gadget driver. That driver data is part of the |
| 495 | * "driver model" infrastructure in 2.6 (and later) kernels, and for |
| 496 | * earlier systems is grouped in a similar structure that's not known |
| 497 | * to the rest of the kernel. |
| 498 | * |
| 499 | * Values of the three OTG device feature flags are updated before the |
| 500 | * setup() call corresponding to USB_REQ_SET_CONFIGURATION, and before |
| 501 | * driver suspend() calls. They are valid only when is_otg, and when the |
| 502 | * device is acting as a B-Peripheral (so is_a_peripheral is false). |
| 503 | */ |
| 504 | struct usb_gadget { |
| 505 | /* readonly to gadget driver */ |
| 506 | const struct usb_gadget_ops *ops; |
| 507 | struct usb_ep *ep0; |
| 508 | struct list_head ep_list; /* of usb_ep */ |
| 509 | enum usb_device_speed speed; |
| 510 | unsigned is_dualspeed:1; |
| 511 | unsigned is_otg:1; |
| 512 | unsigned is_a_peripheral:1; |
| 513 | unsigned b_hnp_enable:1; |
| 514 | unsigned a_hnp_support:1; |
| 515 | unsigned a_alt_hnp_support:1; |
| 516 | const char *name; |
| 517 | struct device dev; |
| 518 | }; |
| 519 | |
| 520 | static inline void set_gadget_data (struct usb_gadget *gadget, void *data) |
| 521 | { dev_set_drvdata (&gadget->dev, data); } |
| 522 | static inline void *get_gadget_data (struct usb_gadget *gadget) |
| 523 | { return dev_get_drvdata (&gadget->dev); } |
| 524 | |
| 525 | /* iterates the non-control endpoints; 'tmp' is a struct usb_ep pointer */ |
| 526 | #define gadget_for_each_ep(tmp,gadget) \ |
| 527 | list_for_each_entry(tmp, &(gadget)->ep_list, ep_list) |
| 528 | |
| 529 | |
| 530 | /** |
| 531 | * usb_gadget_frame_number - returns the current frame number |
| 532 | * @gadget: controller that reports the frame number |
| 533 | * |
| 534 | * Returns the usb frame number, normally eleven bits from a SOF packet, |
| 535 | * or negative errno if this device doesn't support this capability. |
| 536 | */ |
| 537 | static inline int usb_gadget_frame_number (struct usb_gadget *gadget) |
| 538 | { |
| 539 | return gadget->ops->get_frame (gadget); |
| 540 | } |
| 541 | |
| 542 | /** |
| 543 | * usb_gadget_wakeup - tries to wake up the host connected to this gadget |
| 544 | * @gadget: controller used to wake up the host |
| 545 | * |
| 546 | * Returns zero on success, else negative error code if the hardware |
| 547 | * doesn't support such attempts, or its support has not been enabled |
| 548 | * by the usb host. Drivers must return device descriptors that report |
| 549 | * their ability to support this, or hosts won't enable it. |
| 550 | * |
| 551 | * This may also try to use SRP to wake the host and start enumeration, |
| 552 | * even if OTG isn't otherwise in use. OTG devices may also start |
| 553 | * remote wakeup even when hosts don't explicitly enable it. |
| 554 | */ |
| 555 | static inline int usb_gadget_wakeup (struct usb_gadget *gadget) |
| 556 | { |
| 557 | if (!gadget->ops->wakeup) |
| 558 | return -EOPNOTSUPP; |
| 559 | return gadget->ops->wakeup (gadget); |
| 560 | } |
| 561 | |
| 562 | /** |
| 563 | * usb_gadget_set_selfpowered - sets the device selfpowered feature. |
| 564 | * @gadget:the device being declared as self-powered |
| 565 | * |
| 566 | * this affects the device status reported by the hardware driver |
| 567 | * to reflect that it now has a local power supply. |
| 568 | * |
| 569 | * returns zero on success, else negative errno. |
| 570 | */ |
| 571 | static inline int |
| 572 | usb_gadget_set_selfpowered (struct usb_gadget *gadget) |
| 573 | { |
| 574 | if (!gadget->ops->set_selfpowered) |
| 575 | return -EOPNOTSUPP; |
| 576 | return gadget->ops->set_selfpowered (gadget, 1); |
| 577 | } |
| 578 | |
| 579 | /** |
| 580 | * usb_gadget_clear_selfpowered - clear the device selfpowered feature. |
| 581 | * @gadget:the device being declared as bus-powered |
| 582 | * |
| 583 | * this affects the device status reported by the hardware driver. |
| 584 | * some hardware may not support bus-powered operation, in which |
| 585 | * case this feature's value can never change. |
| 586 | * |
| 587 | * returns zero on success, else negative errno. |
| 588 | */ |
| 589 | static inline int |
| 590 | usb_gadget_clear_selfpowered (struct usb_gadget *gadget) |
| 591 | { |
| 592 | if (!gadget->ops->set_selfpowered) |
| 593 | return -EOPNOTSUPP; |
| 594 | return gadget->ops->set_selfpowered (gadget, 0); |
| 595 | } |
| 596 | |
| 597 | /** |
| 598 | * usb_gadget_vbus_connect - Notify controller that VBUS is powered |
| 599 | * @gadget:The device which now has VBUS power. |
| 600 | * |
| 601 | * This call is used by a driver for an external transceiver (or GPIO) |
| 602 | * that detects a VBUS power session starting. Common responses include |
| 603 | * resuming the controller, activating the D+ (or D-) pullup to let the |
| 604 | * host detect that a USB device is attached, and starting to draw power |
| 605 | * (8mA or possibly more, especially after SET_CONFIGURATION). |
| 606 | * |
| 607 | * Returns zero on success, else negative errno. |
| 608 | */ |
| 609 | static inline int |
| 610 | usb_gadget_vbus_connect(struct usb_gadget *gadget) |
| 611 | { |
| 612 | if (!gadget->ops->vbus_session) |
| 613 | return -EOPNOTSUPP; |
| 614 | return gadget->ops->vbus_session (gadget, 1); |
| 615 | } |
| 616 | |
| 617 | /** |
| 618 | * usb_gadget_vbus_draw - constrain controller's VBUS power usage |
| 619 | * @gadget:The device whose VBUS usage is being described |
| 620 | * @mA:How much current to draw, in milliAmperes. This should be twice |
| 621 | * the value listed in the configuration descriptor bMaxPower field. |
| 622 | * |
| 623 | * This call is used by gadget drivers during SET_CONFIGURATION calls, |
| 624 | * reporting how much power the device may consume. For example, this |
| 625 | * could affect how quickly batteries are recharged. |
| 626 | * |
| 627 | * Returns zero on success, else negative errno. |
| 628 | */ |
| 629 | static inline int |
| 630 | usb_gadget_vbus_draw(struct usb_gadget *gadget, unsigned mA) |
| 631 | { |
| 632 | if (!gadget->ops->vbus_draw) |
| 633 | return -EOPNOTSUPP; |
| 634 | return gadget->ops->vbus_draw (gadget, mA); |
| 635 | } |
| 636 | |
| 637 | /** |
| 638 | * usb_gadget_vbus_disconnect - notify controller about VBUS session end |
| 639 | * @gadget:the device whose VBUS supply is being described |
| 640 | * |
| 641 | * This call is used by a driver for an external transceiver (or GPIO) |
| 642 | * that detects a VBUS power session ending. Common responses include |
| 643 | * reversing everything done in usb_gadget_vbus_connect(). |
| 644 | * |
| 645 | * Returns zero on success, else negative errno. |
| 646 | */ |
| 647 | static inline int |
| 648 | usb_gadget_vbus_disconnect(struct usb_gadget *gadget) |
| 649 | { |
| 650 | if (!gadget->ops->vbus_session) |
| 651 | return -EOPNOTSUPP; |
| 652 | return gadget->ops->vbus_session (gadget, 0); |
| 653 | } |
| 654 | |
| 655 | /** |
| 656 | * usb_gadget_connect - software-controlled connect to USB host |
| 657 | * @gadget:the peripheral being connected |
| 658 | * |
| 659 | * Enables the D+ (or potentially D-) pullup. The host will start |
| 660 | * enumerating this gadget when the pullup is active and a VBUS session |
| 661 | * is active (the link is powered). This pullup is always enabled unless |
| 662 | * usb_gadget_disconnect() has been used to disable it. |
| 663 | * |
| 664 | * Returns zero on success, else negative errno. |
| 665 | */ |
| 666 | static inline int |
| 667 | usb_gadget_connect (struct usb_gadget *gadget) |
| 668 | { |
| 669 | if (!gadget->ops->pullup) |
| 670 | return -EOPNOTSUPP; |
| 671 | return gadget->ops->pullup (gadget, 1); |
| 672 | } |
| 673 | |
| 674 | /** |
| 675 | * usb_gadget_disconnect - software-controlled disconnect from USB host |
| 676 | * @gadget:the peripheral being disconnected |
| 677 | * |
| 678 | * Disables the D+ (or potentially D-) pullup, which the host may see |
| 679 | * as a disconnect (when a VBUS session is active). Not all systems |
| 680 | * support software pullup controls. |
| 681 | * |
| 682 | * This routine may be used during the gadget driver bind() call to prevent |
| 683 | * the peripheral from ever being visible to the USB host, unless later |
| 684 | * usb_gadget_connect() is called. For example, user mode components may |
| 685 | * need to be activated before the system can talk to hosts. |
| 686 | * |
| 687 | * Returns zero on success, else negative errno. |
| 688 | */ |
| 689 | static inline int |
| 690 | usb_gadget_disconnect (struct usb_gadget *gadget) |
| 691 | { |
| 692 | if (!gadget->ops->pullup) |
| 693 | return -EOPNOTSUPP; |
| 694 | return gadget->ops->pullup (gadget, 0); |
| 695 | } |
| 696 | |
| 697 | |
| 698 | |
| 699 | /*-------------------------------------------------------------------------*/ |
| 700 | |
| 701 | /** |
| 702 | * struct usb_gadget_driver - driver for usb 'slave' devices |
| 703 | * @function: String describing the gadget's function |
| 704 | * @speed: Highest speed the driver handles. |
| 705 | * @bind: Invoked when the driver is bound to a gadget, usually |
| 706 | * after registering the driver. |
| 707 | * At that point, ep0 is fully initialized, and ep_list holds |
| 708 | * the currently-available endpoints. |
| 709 | * Called in a context that permits sleeping. |
| 710 | * @setup: Invoked for ep0 control requests that aren't handled by |
| 711 | * the hardware level driver. Most calls must be handled by |
| 712 | * the gadget driver, including descriptor and configuration |
| 713 | * management. The 16 bit members of the setup data are in |
David Brownell | 1bbc169 | 2005-05-07 13:05:13 -0700 | [diff] [blame] | 714 | * USB byte order. Called in_interrupt; this may not sleep. Driver |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 715 | * queues a response to ep0, or returns negative to stall. |
| 716 | * @disconnect: Invoked after all transfers have been stopped, |
| 717 | * when the host is disconnected. May be called in_interrupt; this |
| 718 | * may not sleep. Some devices can't detect disconnect, so this might |
| 719 | * not be called except as part of controller shutdown. |
| 720 | * @unbind: Invoked when the driver is unbound from a gadget, |
| 721 | * usually from rmmod (after a disconnect is reported). |
| 722 | * Called in a context that permits sleeping. |
| 723 | * @suspend: Invoked on USB suspend. May be called in_interrupt. |
| 724 | * @resume: Invoked on USB resume. May be called in_interrupt. |
| 725 | * @driver: Driver model state for this driver. |
| 726 | * |
| 727 | * Devices are disabled till a gadget driver successfully bind()s, which |
| 728 | * means the driver will handle setup() requests needed to enumerate (and |
| 729 | * meet "chapter 9" requirements) then do some useful work. |
| 730 | * |
| 731 | * If gadget->is_otg is true, the gadget driver must provide an OTG |
| 732 | * descriptor during enumeration, or else fail the bind() call. In such |
| 733 | * cases, no USB traffic may flow until both bind() returns without |
| 734 | * having called usb_gadget_disconnect(), and the USB host stack has |
| 735 | * initialized. |
| 736 | * |
| 737 | * Drivers use hardware-specific knowledge to configure the usb hardware. |
| 738 | * endpoint addressing is only one of several hardware characteristics that |
| 739 | * are in descriptors the ep0 implementation returns from setup() calls. |
| 740 | * |
| 741 | * Except for ep0 implementation, most driver code shouldn't need change to |
| 742 | * run on top of different usb controllers. It'll use endpoints set up by |
| 743 | * that ep0 implementation. |
| 744 | * |
| 745 | * The usb controller driver handles a few standard usb requests. Those |
| 746 | * include set_address, and feature flags for devices, interfaces, and |
| 747 | * endpoints (the get_status, set_feature, and clear_feature requests). |
| 748 | * |
| 749 | * Accordingly, the driver's setup() callback must always implement all |
| 750 | * get_descriptor requests, returning at least a device descriptor and |
| 751 | * a configuration descriptor. Drivers must make sure the endpoint |
| 752 | * descriptors match any hardware constraints. Some hardware also constrains |
| 753 | * other descriptors. (The pxa250 allows only configurations 1, 2, or 3). |
| 754 | * |
| 755 | * The driver's setup() callback must also implement set_configuration, |
| 756 | * and should also implement set_interface, get_configuration, and |
| 757 | * get_interface. Setting a configuration (or interface) is where |
| 758 | * endpoints should be activated or (config 0) shut down. |
| 759 | * |
| 760 | * (Note that only the default control endpoint is supported. Neither |
| 761 | * hosts nor devices generally support control traffic except to ep0.) |
| 762 | * |
| 763 | * Most devices will ignore USB suspend/resume operations, and so will |
| 764 | * not provide those callbacks. However, some may need to change modes |
| 765 | * when the host is not longer directing those activities. For example, |
| 766 | * local controls (buttons, dials, etc) may need to be re-enabled since |
| 767 | * the (remote) host can't do that any longer; or an error state might |
| 768 | * be cleared, to make the device behave identically whether or not |
| 769 | * power is maintained. |
| 770 | */ |
| 771 | struct usb_gadget_driver { |
| 772 | char *function; |
| 773 | enum usb_device_speed speed; |
| 774 | int (*bind)(struct usb_gadget *); |
| 775 | void (*unbind)(struct usb_gadget *); |
| 776 | int (*setup)(struct usb_gadget *, |
| 777 | const struct usb_ctrlrequest *); |
| 778 | void (*disconnect)(struct usb_gadget *); |
| 779 | void (*suspend)(struct usb_gadget *); |
| 780 | void (*resume)(struct usb_gadget *); |
| 781 | |
| 782 | // FIXME support safe rmmod |
| 783 | struct device_driver driver; |
| 784 | }; |
| 785 | |
| 786 | |
| 787 | |
| 788 | /*-------------------------------------------------------------------------*/ |
| 789 | |
| 790 | /* driver modules register and unregister, as usual. |
| 791 | * these calls must be made in a context that can sleep. |
| 792 | * |
| 793 | * these will usually be implemented directly by the hardware-dependent |
| 794 | * usb bus interface driver, which will only support a single driver. |
| 795 | */ |
| 796 | |
| 797 | /** |
| 798 | * usb_gadget_register_driver - register a gadget driver |
| 799 | * @driver:the driver being registered |
| 800 | * |
| 801 | * Call this in your gadget driver's module initialization function, |
| 802 | * to tell the underlying usb controller driver about your driver. |
| 803 | * The driver's bind() function will be called to bind it to a |
| 804 | * gadget. This function must be called in a context that can sleep. |
| 805 | */ |
| 806 | int usb_gadget_register_driver (struct usb_gadget_driver *driver); |
| 807 | |
| 808 | /** |
| 809 | * usb_gadget_unregister_driver - unregister a gadget driver |
| 810 | * @driver:the driver being unregistered |
| 811 | * |
| 812 | * Call this in your gadget driver's module cleanup function, |
| 813 | * to tell the underlying usb controller that your driver is |
| 814 | * going away. If the controller is connected to a USB host, |
| 815 | * it will first disconnect(). The driver is also requested |
| 816 | * to unbind() and clean up any device state, before this procedure |
| 817 | * finally returns. |
| 818 | * This function must be called in a context that can sleep. |
| 819 | */ |
| 820 | int usb_gadget_unregister_driver (struct usb_gadget_driver *driver); |
| 821 | |
| 822 | /*-------------------------------------------------------------------------*/ |
| 823 | |
| 824 | /* utility to simplify dealing with string descriptors */ |
| 825 | |
| 826 | /** |
| 827 | * struct usb_string - wraps a C string and its USB id |
| 828 | * @id:the (nonzero) ID for this string |
| 829 | * @s:the string, in UTF-8 encoding |
| 830 | * |
| 831 | * If you're using usb_gadget_get_string(), use this to wrap a string |
| 832 | * together with its ID. |
| 833 | */ |
| 834 | struct usb_string { |
| 835 | u8 id; |
| 836 | const char *s; |
| 837 | }; |
| 838 | |
| 839 | /** |
| 840 | * struct usb_gadget_strings - a set of USB strings in a given language |
| 841 | * @language:identifies the strings' language (0x0409 for en-us) |
| 842 | * @strings:array of strings with their ids |
| 843 | * |
| 844 | * If you're using usb_gadget_get_string(), use this to wrap all the |
| 845 | * strings for a given language. |
| 846 | */ |
| 847 | struct usb_gadget_strings { |
| 848 | u16 language; /* 0x0409 for en-us */ |
| 849 | struct usb_string *strings; |
| 850 | }; |
| 851 | |
| 852 | /* put descriptor for string with that id into buf (buflen >= 256) */ |
| 853 | int usb_gadget_get_string (struct usb_gadget_strings *table, int id, u8 *buf); |
| 854 | |
| 855 | /*-------------------------------------------------------------------------*/ |
| 856 | |
| 857 | /* utility to simplify managing config descriptors */ |
| 858 | |
| 859 | /* write vector of descriptors into buffer */ |
| 860 | int usb_descriptor_fillbuf(void *, unsigned, |
| 861 | const struct usb_descriptor_header **); |
| 862 | |
| 863 | /* build config descriptor from single descriptor vector */ |
| 864 | int usb_gadget_config_buf(const struct usb_config_descriptor *config, |
| 865 | void *buf, unsigned buflen, const struct usb_descriptor_header **desc); |
| 866 | |
| 867 | /*-------------------------------------------------------------------------*/ |
| 868 | |
| 869 | /* utility wrapping a simple endpoint selection policy */ |
| 870 | |
| 871 | extern struct usb_ep *usb_ep_autoconfig (struct usb_gadget *, |
| 872 | struct usb_endpoint_descriptor *) __init; |
| 873 | |
| 874 | extern void usb_ep_autoconfig_reset (struct usb_gadget *) __init; |
| 875 | |
| 876 | #endif /* __KERNEL__ */ |
| 877 | |
| 878 | #endif /* __LINUX_USB_GADGET_H */ |