flight/pios/stm32f4xx/pios_usb_cdc.c

   1 /**
   2  ******************************************************************************
   3  * @addtogroup PIOS PIOS Core hardware abstraction layer
   4  * @{
   5  * @addtogroup   PIOS_USB_COM USB COM Functions
   6  * @brief PIOS USB COM implementation for CDC interfaces
   7  * @notes      This implements a CDC Serial Port
   8  * @{
   9  *
  10  * @file       pios_usb_com_cdc.c
  11  * @author     The OpenPilot Team, http://www.openpilot.org Copyright (C) 2010.
  12  * @brief      USB COM functions (STM32 dependent code)
  13  * @see        The GNU Public License (GPL) Version 3
  14  *
  15  *****************************************************************************/
  16 /*
  17  * This program is free software; you can redistribute it and/or modify
  18  * it under the terms of the GNU General Public License as published by
  19  * the Free Software Foundation; either version 3 of the License, or
  20  * (at your option) any later version.
  21  *
  22  * This program is distributed in the hope that it will be useful, but
  23  * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
  24  * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
  25  * for more details.
  26  *
  27  * You should have received a copy of the GNU General Public License along
  28  * with this program; if not, write to the Free Software Foundation, Inc.,
  29  * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
  30  */
  31
  32 #include "pios.h"
  33
  34 #ifdef PIOS_INCLUDE_USB_CDC
  35
  36 #include "pios_usb_cdc_priv.h"
  37 #include "pios_usb_board_data.h" /* PIOS_BOARD_*_DATA_LENGTH */
  38 #include "pios_usbhook.h" /* PIOS_USBHOOK_* */
  39
  40 /* Implement COM layer driver API */
  41 static void PIOS_USB_CDC_RegisterTxCallback(uint32_t usbcdc_id, pios_com_callback tx_out_cb, uint32_t context);
  42 static void PIOS_USB_CDC_RegisterRxCallback(uint32_t usbcdc_id, pios_com_callback rx_in_cb, uint32_t context);
  43 static void PIOS_USB_CDC_TxStart(uint32_t usbcdc_id, uint16_t tx_bytes_avail);
  44 static void PIOS_USB_CDC_RxStart(uint32_t usbcdc_id, uint16_t rx_bytes_avail);
  45 static bool PIOS_USB_CDC_Available(uint32_t usbcdc_id);
  46
  47 const struct pios_com_driver pios_usb_cdc_com_driver = {
  48     .tx_start   = PIOS_USB_CDC_TxStart,
  49     .rx_start   = PIOS_USB_CDC_RxStart,
  50     .bind_tx_cb = PIOS_USB_CDC_RegisterTxCallback,
  51     .bind_rx_cb = PIOS_USB_CDC_RegisterRxCallback,
  52     .available  = PIOS_USB_CDC_Available,
  53 };
  54
  55 enum pios_usb_cdc_dev_magic {
  56     PIOS_USB_CDC_DEV_MAGIC = 0xAABBCCDD,
  57 };
  58
  59 struct pios_usb_cdc_dev {
  60     enum pios_usb_cdc_dev_magic   magic;
  61     const struct pios_usb_cdc_cfg *cfg;
  62
  63     uint32_t lower_id;
  64
  65     pios_com_callback rx_in_cb;
  66     uint32_t rx_in_context;
  67     pios_com_callback tx_out_cb;
  68     uint32_t tx_out_context;
  69
  70     bool     usb_ctrl_if_enabled;
  71     bool     usb_data_if_enabled;
  72
  73     uint8_t  rx_packet_buffer[PIOS_USB_BOARD_CDC_DATA_LENGTH] __attribute__((aligned(4)));
  74     volatile bool rx_active;
  75
  76     /*
  77      * NOTE: This is -1 as somewhat of a hack.  It ensures that we always send packets
  78      * that are strictly < maxPacketSize for this interface which means we never have
  79      * to bother with zero length packets (ZLP).
  80      */
  81     uint8_t  tx_packet_buffer[PIOS_USB_BOARD_CDC_DATA_LENGTH - 1] __attribute__((aligned(4)));
  82     volatile bool tx_active;
  83
  84     uint8_t  ctrl_tx_packet_buffer[PIOS_USB_BOARD_CDC_MGMT_LENGTH] __attribute__((aligned(4)));
  85
  86     uint32_t rx_dropped;
  87     uint32_t rx_oversize;
  88
  89     /*
  90      * Used to hold the current state of the simulated UART.  Changes to this
  91      * variable may trigger new USB CDC Notification packets to be sent to the host.
  92      */
  93     volatile uint16_t prev_uart_state;
  94 };
  95
  96 static bool PIOS_USB_CDC_validate(struct pios_usb_cdc_dev *usb_cdc_dev)
  97 {
  98     return usb_cdc_dev && (usb_cdc_dev->magic == PIOS_USB_CDC_DEV_MAGIC);
  99 }
 100
 101 #if defined(PIOS_INCLUDE_FREERTOS)
 102 static struct pios_usb_cdc_dev *PIOS_USB_CDC_alloc(void)
 103 {
 104     struct pios_usb_cdc_dev *usb_cdc_dev;
 105
 106     usb_cdc_dev = (struct pios_usb_cdc_dev *)pios_malloc(sizeof(struct pios_usb_cdc_dev));
 107     if (!usb_cdc_dev) {
 108         return NULL;
 109     }
 110
 111     memset(usb_cdc_dev, 0, sizeof(struct pios_usb_cdc_dev));
 112     usb_cdc_dev->magic = PIOS_USB_CDC_DEV_MAGIC;
 113     return usb_cdc_dev;
 114 }
 115 #else
 116 static struct pios_usb_cdc_dev pios_usb_cdc_devs[PIOS_USB_CDC_MAX_DEVS];
 117 static uint8_t pios_usb_cdc_num_devs;
 118 static struct pios_usb_cdc_dev *PIOS_USB_CDC_alloc(void)
 119 {
 120     struct pios_usb_cdc_dev *usb_cdc_dev;
 121
 122     if (pios_usb_cdc_num_devs >= PIOS_USB_CDC_MAX_DEVS) {
 123         return NULL;
 124     }
 125
 126     usb_cdc_dev = &pios_usb_cdc_devs[pios_usb_cdc_num_devs++];
 127
 128     memset(usb_cdc_dev, 0, sizeof(struct pios_usb_cdc_dev));
 129     usb_cdc_dev->magic = PIOS_USB_CDC_DEV_MAGIC;
 130
 131     return usb_cdc_dev;
 132 }
 133 #endif /* if defined(PIOS_INCLUDE_FREERTOS) */
 134
 135 /* Implement USB_IFOPS for CDC Control Interface */
 136 static void PIOS_USB_CDC_CTRL_IF_Init(uint32_t usb_cdc_id);
 137 static void PIOS_USB_CDC_CTRL_IF_DeInit(uint32_t usb_cdc_id);
 138 static bool PIOS_USB_CDC_CTRL_IF_Setup(uint32_t usb_cdc_id, struct usb_setup_request *req);
 139 static void PIOS_USB_CDC_CTRL_IF_CtrlDataOut(uint32_t usb_cdc_id, const struct usb_setup_request *req);
 140
 141 static struct pios_usb_ifops usb_cdc_ctrl_ifops = {
 142     .init   = PIOS_USB_CDC_CTRL_IF_Init,
 143     .deinit = PIOS_USB_CDC_CTRL_IF_DeInit,
 144     .setup  = PIOS_USB_CDC_CTRL_IF_Setup,
 145     .ctrl_data_out = PIOS_USB_CDC_CTRL_IF_CtrlDataOut,
 146 };
 147
 148 /* Implement USB_IFOPS for CDC Data Interface */
 149 static void PIOS_USB_CDC_DATA_IF_Init(uint32_t usb_cdc_id);
 150 static void PIOS_USB_CDC_DATA_IF_DeInit(uint32_t usb_cdc_id);
 151 static bool PIOS_USB_CDC_DATA_IF_Setup(uint32_t usb_cdc_id, struct usb_setup_request *req);
 152 static void PIOS_USB_CDC_DATA_IF_CtrlDataOut(uint32_t usb_cdc_id, const struct usb_setup_request *req);
 153
 154 static struct pios_usb_ifops usb_cdc_data_ifops = {
 155     .init   = PIOS_USB_CDC_DATA_IF_Init,
 156     .deinit = PIOS_USB_CDC_DATA_IF_DeInit,
 157     .setup  = PIOS_USB_CDC_DATA_IF_Setup,
 158     .ctrl_data_out = PIOS_USB_CDC_DATA_IF_CtrlDataOut,
 159 };
 160
 161 static uint32_t pios_usb_cdc_id;
 162
 163 int32_t PIOS_USB_CDC_Init(uint32_t *usbcdc_id, const struct pios_usb_cdc_cfg *cfg, uint32_t lower_id)
 164 {
 165     PIOS_Assert(usbcdc_id);
 166     PIOS_Assert(cfg);
 167
 168     struct pios_usb_cdc_dev *usb_cdc_dev;
 169
 170     usb_cdc_dev = (struct pios_usb_cdc_dev *)PIOS_USB_CDC_alloc();
 171     if (!usb_cdc_dev) {
 172         goto out_fail;
 173     }
 174
 175     /* Bind the configuration to the device instance */
 176     usb_cdc_dev->cfg = cfg;
 177     usb_cdc_dev->lower_id = lower_id;
 178
 179     pios_usb_cdc_id  = (uint32_t)usb_cdc_dev;
 180
 181     /* Rx and Tx are not active yet */
 182     usb_cdc_dev->rx_active           = false;
 183     usb_cdc_dev->tx_active           = false;
 184
 185     /* Clear stats */
 186     usb_cdc_dev->rx_dropped          = 0;
 187     usb_cdc_dev->rx_oversize         = 0;
 188
 189     /* Initialize the uart state */
 190     usb_cdc_dev->prev_uart_state     = 0;
 191
 192     /* Register class specific interface callbacks with the USBHOOK layer */
 193     usb_cdc_dev->usb_ctrl_if_enabled = false;
 194     PIOS_USBHOOK_RegisterIfOps(cfg->ctrl_if, &usb_cdc_ctrl_ifops, (uint32_t)usb_cdc_dev);
 195
 196     /* Register class specific interface callbacks with the USBHOOK layer */
 197     usb_cdc_dev->usb_data_if_enabled = false;
 198     PIOS_USBHOOK_RegisterIfOps(cfg->data_if, &usb_cdc_data_ifops, (uint32_t)usb_cdc_dev);
 199
 200     *usbcdc_id = (uint32_t)usb_cdc_dev;
 201
 202     return 0;
 203
 204 out_fail:
 205     return -1;
 206 }
 207
 208 static bool PIOS_USB_CDC_SendData(struct pios_usb_cdc_dev *usb_cdc_dev)
 209 {
 210     uint16_t bytes_to_tx;
 211
 212     if (!usb_cdc_dev->tx_out_cb) {
 213         return false;
 214     }
 215
 216     bool need_yield = false;
 217     bytes_to_tx = (usb_cdc_dev->tx_out_cb)(usb_cdc_dev->tx_out_context,
 218                                            usb_cdc_dev->tx_packet_buffer,
 219                                            sizeof(usb_cdc_dev->tx_packet_buffer),
 220                                            NULL,
 221                                            &need_yield);
 222     if (bytes_to_tx == 0) {
 223         return false;
 224     }
 225
 226     /*
 227      * Mark this endpoint as being tx active _before_ actually transmitting
 228      * to make sure we don't race with the Tx completion interrupt
 229      */
 230     usb_cdc_dev->tx_active = true;
 231
 232     PIOS_USBHOOK_EndpointTx(usb_cdc_dev->cfg->data_tx_ep,
 233                             usb_cdc_dev->tx_packet_buffer,
 234                             bytes_to_tx);
 235
 236 #if defined(PIOS_INCLUDE_FREERTOS)
 237     if (need_yield) {
 238         vPortYield();
 239     }
 240 #endif /* PIOS_INCLUDE_FREERTOS */
 241
 242     return true;
 243 }
 244
 245 static void PIOS_USB_CDC_RxStart(uint32_t usbcdc_id, uint16_t rx_bytes_avail)
 246 {
 247     struct pios_usb_cdc_dev *usb_cdc_dev = (struct pios_usb_cdc_dev *)usbcdc_id;
 248
 249     bool valid = PIOS_USB_CDC_validate(usb_cdc_dev);
 250
 251     PIOS_Assert(valid);
 252
 253     /* Make sure this USB interface has been initialized */
 254     if (!usb_cdc_dev->usb_data_if_enabled) {
 255         return;
 256     }
 257
 258     if (!PIOS_USB_CheckAvailable(usb_cdc_dev->lower_id)) {
 259         return;
 260     }
 261
 262     // If endpoint was stalled and there is now space make it valid
 263     if (!usb_cdc_dev->rx_active && (rx_bytes_avail >= PIOS_USB_BOARD_CDC_DATA_LENGTH)) {
 264         PIOS_USBHOOK_EndpointRx(usb_cdc_dev->cfg->data_rx_ep,
 265                                 usb_cdc_dev->rx_packet_buffer,
 266                                 sizeof(usb_cdc_dev->rx_packet_buffer));
 267         usb_cdc_dev->rx_active = true;
 268     }
 269 }
 270
 271 static void PIOS_USB_CDC_TxStart(uint32_t usbcdc_id, __attribute__((unused)) uint16_t tx_bytes_avail)
 272 {
 273     struct pios_usb_cdc_dev *usb_cdc_dev = (struct pios_usb_cdc_dev *)usbcdc_id;
 274
 275     bool valid = PIOS_USB_CDC_validate(usb_cdc_dev);
 276
 277     PIOS_Assert(valid);
 278
 279     /* Make sure this USB interface has been initialized */
 280     if (!usb_cdc_dev->usb_data_if_enabled) {
 281         return;
 282     }
 283
 284     if (!PIOS_USB_CheckAvailable(usb_cdc_dev->lower_id)) {
 285         return;
 286     }
 287
 288     if (!usb_cdc_dev->tx_active) {
 289         /* Transmitter is not currently active, send a report */
 290         PIOS_USB_CDC_SendData(usb_cdc_dev);
 291     }
 292 }
 293
 294 static void PIOS_USB_CDC_RegisterRxCallback(uint32_t usbcdc_id, pios_com_callback rx_in_cb, uint32_t context)
 295 {
 296     struct pios_usb_cdc_dev *usb_cdc_dev = (struct pios_usb_cdc_dev *)usbcdc_id;
 297
 298     bool valid = PIOS_USB_CDC_validate(usb_cdc_dev);
 299
 300     PIOS_Assert(valid);
 301
 302     /*
 303      * Order is important in these assignments since ISR uses _cb
 304      * field to determine if it's ok to dereference _cb and _context
 305      */
 306     usb_cdc_dev->rx_in_context = context;
 307     usb_cdc_dev->rx_in_cb = rx_in_cb;
 308 }
 309
 310 static void PIOS_USB_CDC_RegisterTxCallback(uint32_t usbcdc_id, pios_com_callback tx_out_cb, uint32_t context)
 311 {
 312     struct pios_usb_cdc_dev *usb_cdc_dev = (struct pios_usb_cdc_dev *)usbcdc_id;
 313
 314     bool valid = PIOS_USB_CDC_validate(usb_cdc_dev);
 315
 316     PIOS_Assert(valid);
 317
 318     /*
 319      * Order is important in these assignments since ISR uses _cb
 320      * field to determine if it's ok to dereference _cb and _context
 321      */
 322     usb_cdc_dev->tx_out_context = context;
 323     usb_cdc_dev->tx_out_cb = tx_out_cb;
 324 }
 325
 326 static bool PIOS_USB_CDC_CTRL_EP_IN_Callback(uint32_t usb_cdc_id, uint8_t epnum, uint16_t len);
 327
 328 static void PIOS_USB_CDC_CTRL_IF_Init(uint32_t usb_cdc_id)
 329 {
 330     struct pios_usb_cdc_dev *usb_cdc_dev = (struct pios_usb_cdc_dev *)usb_cdc_id;
 331
 332     if (!PIOS_USB_CDC_validate(usb_cdc_dev)) {
 333         return;
 334     }
 335
 336     /* Register endpoint specific callbacks with the USBHOOK layer */
 337     PIOS_USBHOOK_RegisterEpInCallback(usb_cdc_dev->cfg->ctrl_tx_ep,
 338                                       sizeof(usb_cdc_dev->ctrl_tx_packet_buffer),
 339                                       PIOS_USB_CDC_CTRL_EP_IN_Callback,
 340                                       (uint32_t)usb_cdc_dev);
 341     usb_cdc_dev->usb_ctrl_if_enabled = true;
 342 }
 343
 344 static void PIOS_USB_CDC_CTRL_IF_DeInit(uint32_t usb_cdc_id)
 345 {
 346     struct pios_usb_cdc_dev *usb_cdc_dev = (struct pios_usb_cdc_dev *)usb_cdc_id;
 347
 348     if (!PIOS_USB_CDC_validate(usb_cdc_dev)) {
 349         return;
 350     }
 351
 352     /* DeRegister endpoint specific callbacks with the USBHOOK layer */
 353     usb_cdc_dev->usb_data_if_enabled = false;
 354 }
 355
 356 static uint8_t cdc_altset;
 357 static struct usb_cdc_line_coding line_coding = {
 358     .dwDTERate   = htousbl(57600),
 359     .bCharFormat = USB_CDC_LINE_CODING_STOP_1,
 360     .bParityType = USB_CDC_LINE_CODING_PARITY_NONE,
 361     .bDataBits   = 8,
 362 };
 363
 364 static uint16_t control_line_state;
 365
 366 static bool PIOS_USB_CDC_CTRL_IF_Setup(uint32_t usb_cdc_id, struct usb_setup_request *req)
 367 {
 368     struct pios_usb_cdc_dev *usb_cdc_dev = (struct pios_usb_cdc_dev *)usb_cdc_id;
 369
 370     if (!PIOS_USB_CDC_validate(usb_cdc_dev)) {
 371         return false;
 372     }
 373
 374     /* Make sure this is a request for an interface we know about */
 375     uint8_t ifnum = req->wIndex & 0xFF;
 376     if (ifnum != usb_cdc_dev->cfg->ctrl_if) {
 377         return false;
 378     }
 379
 380     switch (req->bmRequestType & (USB_REQ_TYPE_MASK | USB_REQ_RECIPIENT_MASK)) {
 381     case (USB_REQ_TYPE_STANDARD | USB_REQ_RECIPIENT_INTERFACE):
 382         switch (req->bRequest) {
 383         case USB_REQ_GET_INTERFACE:
 384             PIOS_USBHOOK_CtrlTx(&cdc_altset, 1);
 385             break;
 386         case USB_REQ_SET_INTERFACE:
 387             cdc_altset = (uint8_t)(req->wValue);
 388             break;
 389         default:
 390             /* Unhandled standard request */
 391             return false;
 392
 393             break;
 394         }
 395         break;
 396     case (USB_REQ_TYPE_CLASS | USB_REQ_RECIPIENT_INTERFACE):
 397         switch (req->bRequest) {
 398         case USB_CDC_REQ_SET_LINE_CODING:
 399             PIOS_USBHOOK_CtrlRx((uint8_t *)&line_coding, sizeof(line_coding));
 400             break;
 401         case USB_CDC_REQ_GET_LINE_CODING:
 402             PIOS_USBHOOK_CtrlTx((uint8_t *)&line_coding, sizeof(line_coding));
 403             break;
 404         case USB_CDC_REQ_SET_CONTROL_LINE_STATE:
 405             control_line_state = req->wValue;
 406             break;
 407         default:
 408             /* Unhandled class request */
 409             return false;
 410
 411             break;
 412         }
 413         break;
 414     default:
 415         /* Unhandled request */
 416         return false;
 417     }
 418
 419     return true;
 420 }
 421
 422 static bool PIOS_USB_CDC_Available(uint32_t usbcdc_id)
 423 {
 424     struct pios_usb_cdc_dev *usb_cdc_dev = (struct pios_usb_cdc_dev *)usbcdc_id;
 425
 426     bool valid = PIOS_USB_CDC_validate(usb_cdc_dev);
 427
 428     PIOS_Assert(valid);
 429
 430     return PIOS_USB_CheckAvailable(usb_cdc_dev->lower_id) &&
 431            (control_line_state & USB_CDC_CONTROL_LINE_STATE_DTE_PRESENT);
 432 }
 433
 434 /**
 435  * Called *after* the data has been written to the buffer provided in the setup stage.  The
 436  * setup request is passed in here again so we know *which* EP0 data out has just completed.
 437  */
 438 static void PIOS_USB_CDC_CTRL_IF_CtrlDataOut(uint32_t usb_cdc_id, const struct usb_setup_request *req)
 439 {
 440     struct pios_usb_cdc_dev *usb_cdc_dev = (struct pios_usb_cdc_dev *)usb_cdc_id;
 441
 442     if (!PIOS_USB_CDC_validate(usb_cdc_dev)) {
 443         return;
 444     }
 445
 446     /* Make sure this is a request for an interface we know about */
 447     uint8_t ifnum = req->wIndex & 0xFF;
 448     if (ifnum != usb_cdc_dev->cfg->ctrl_if) {
 449         return;
 450     }
 451
 452     switch (req->bmRequestType & (USB_REQ_TYPE_MASK | USB_REQ_RECIPIENT_MASK)) {
 453     case (USB_REQ_TYPE_STANDARD | USB_REQ_RECIPIENT_INTERFACE):
 454         switch (req->bRequest) {
 455         default:
 456             /* Unhandled standard request */
 457             return;
 458
 459             break;
 460         }
 461         break;
 462     case (USB_REQ_TYPE_CLASS | USB_REQ_RECIPIENT_INTERFACE):
 463         switch (req->bRequest) {
 464         case USB_CDC_REQ_SET_LINE_CODING:
 465             /*
 466              * If we cared to, this is where we would apply the new line coding
 467              * that is now stored in the line_coding struct.  This could be used
 468              * to notify the upper COM layer that the baud rate has changed.  This
 469              * may be useful in the case of a COM USB bridge where we would
 470              * auto-adjust the USART baud rate based on the line coding set here.
 471              */
 472             break;
 473         default:
 474             /* Unhandled class request */
 475             return;
 476
 477             break;
 478         }
 479         break;
 480     default:
 481         /* Unhandled request */
 482         return;
 483     }
 484 }
 485
 486 static struct usb_cdc_serial_state_report uart_state = {
 487     .bmRequestType = 0xA1,
 488     .bNotification = USB_CDC_NOTIFICATION_SERIAL_STATE,
 489     .wValue      = 0,
 490     .wIndex      = htousbs(1),
 491     .wLength     = htousbs(2),
 492     .bmUartState = htousbs(0),
 493 };
 494
 495 static bool PIOS_USB_CDC_CTRL_EP_IN_Callback(
 496     __attribute__((unused)) uint32_t usb_cdc_id,
 497     __attribute__((unused)) uint8_t epnum,
 498     __attribute__((unused)) uint16_t len)
 499 {
 500     struct pios_usb_cdc_dev *usb_cdc_dev = (struct pios_usb_cdc_dev *)pios_usb_cdc_id;
 501
 502     bool valid = PIOS_USB_CDC_validate(usb_cdc_dev);
 503
 504     PIOS_Assert(valid);
 505
 506     /* Give back UART State Bitmap */
 507     /* UART State Bitmap
 508      *   15-7: reserved
 509      *      6:  bOverRun    overrun error
 510      *      5:  bParity     parity error
 511      *      4:  bFraming    framing error
 512      *      3:  bRingSignal RI
 513      *      2:  bBreak      break reception
 514      *      1:  bTxCarrier  DSR
 515      *      0:  bRxCarrier  DCD
 516      */
 517
 518     /* Currently, we only handle TxCarrier and RxCarrier reporting */
 519     uint16_t new_uart_state = 0;
 520     if (usb_cdc_dev->tx_out_cb) {
 521         /* Someone is going to providing FC->PC data, advertise an RxCarrier to the host */
 522         new_uart_state |= 0x1;
 523     }
 524     if (usb_cdc_dev->rx_in_cb) {
 525         /* Someone is consuming PC->FC data, advertise a TxCarrier to the host */
 526         new_uart_state |= 0x2;
 527     }
 528
 529     /* Has anything changed since we last sent a notification? */
 530     if ((new_uart_state ^ usb_cdc_dev->prev_uart_state) & 0x3) {
 531         usb_cdc_dev->prev_uart_state = new_uart_state;
 532
 533         uart_state.bmUartState = htousbs(new_uart_state);
 534
 535         PIOS_USBHOOK_EndpointTx(usb_cdc_dev->cfg->ctrl_tx_ep,
 536                                 (uint8_t *)&uart_state,
 537                                 sizeof(uart_state));
 538     }
 539
 540     return true;
 541 }
 542
 543 static bool PIOS_USB_CDC_DATA_EP_IN_Callback(uint32_t usb_cdc_id, uint8_t epnum, uint16_t len);
 544 static bool PIOS_USB_CDC_DATA_EP_OUT_Callback(uint32_t usb_cdc_id, uint8_t epnum, uint16_t len);
 545
 546 static void PIOS_USB_CDC_DATA_IF_Init(uint32_t usb_cdc_id)
 547 {
 548     struct pios_usb_cdc_dev *usb_cdc_dev = (struct pios_usb_cdc_dev *)usb_cdc_id;
 549
 550     if (!PIOS_USB_CDC_validate(usb_cdc_dev)) {
 551         return;
 552     }
 553
 554     /* Register endpoint specific callbacks with the USBHOOK layer */
 555     PIOS_USBHOOK_RegisterEpInCallback(usb_cdc_dev->cfg->data_tx_ep,
 556                                       sizeof(usb_cdc_dev->tx_packet_buffer),
 557                                       PIOS_USB_CDC_DATA_EP_IN_Callback,
 558                                       (uint32_t)usb_cdc_dev);
 559     PIOS_USBHOOK_RegisterEpOutCallback(usb_cdc_dev->cfg->data_rx_ep,
 560                                        sizeof(usb_cdc_dev->rx_packet_buffer),
 561                                        PIOS_USB_CDC_DATA_EP_OUT_Callback,
 562                                        (uint32_t)usb_cdc_dev);
 563     usb_cdc_dev->usb_data_if_enabled = true;
 564 }
 565
 566 static void PIOS_USB_CDC_DATA_IF_DeInit(uint32_t usb_cdc_id)
 567 {
 568     struct pios_usb_cdc_dev *usb_cdc_dev = (struct pios_usb_cdc_dev *)usb_cdc_id;
 569
 570     if (!PIOS_USB_CDC_validate(usb_cdc_dev)) {
 571         return;
 572     }
 573
 574     /* DeRegister endpoint specific callbacks with the USBHOOK layer */
 575     usb_cdc_dev->usb_data_if_enabled = false;
 576     PIOS_USBHOOK_DeRegisterEpInCallback(usb_cdc_dev->cfg->data_tx_ep);
 577     PIOS_USBHOOK_DeRegisterEpOutCallback(usb_cdc_dev->cfg->data_rx_ep);
 578 }
 579
 580 static bool PIOS_USB_CDC_DATA_IF_Setup(
 581     __attribute__((unused)) uint32_t usb_cdc_id,
 582     __attribute__((unused)) struct usb_setup_request *req)
 583 {
 584     /* There are no valid EP0 transactions for CDC DATA interfaces */
 585     PIOS_Assert(0);
 586
 587     return false;
 588 }
 589
 590 /**
 591  * Called *after* the data has been written to the buffer provided in the setup stage.  The
 592  * setup request is passed in here again so we know *which* EP0 data out has just completed.
 593  */
 594 static void PIOS_USB_CDC_DATA_IF_CtrlDataOut(
 595     __attribute__((unused)) uint32_t usb_cdc_id,
 596     __attribute__((unused)) const struct usb_setup_request *req)
 597 {
 598     /* CDC DATA interfaces don't have any OUT data stages on the control endpoint */
 599     PIOS_Assert(0);
 600 }
 601
 602 /**
 603  * @brief Callback used to indicate a transmission from device INto host completed
 604  * Checks if any data remains, pads it into HID packet and sends.
 605  */
 606 static bool PIOS_USB_CDC_DATA_EP_IN_Callback(
 607     __attribute__((unused)) uint32_t usb_cdc_id,
 608     __attribute__((unused)) uint8_t epnum,
 609     __attribute__((unused)) uint16_t len)
 610 {
 611     struct pios_usb_cdc_dev *usb_cdc_dev = (struct pios_usb_cdc_dev *)pios_usb_cdc_id;
 612
 613     bool valid = PIOS_USB_CDC_validate(usb_cdc_dev);
 614
 615     PIOS_Assert(valid);
 616
 617     bool rc = PIOS_USB_CDC_SendData(usb_cdc_dev);
 618     if (!rc) {
 619         /* No additional data was transmitted, note that tx is no longer active */
 620         usb_cdc_dev->tx_active = false;
 621     }
 622
 623     return rc;
 624 }
 625
 626 static bool PIOS_USB_CDC_DATA_EP_OUT_Callback(
 627     __attribute__((unused)) uint32_t usb_cdc_id,
 628     __attribute__((unused)) uint8_t epnum,
 629     uint16_t len)
 630 {
 631     struct pios_usb_cdc_dev *usb_cdc_dev = (struct pios_usb_cdc_dev *)pios_usb_cdc_id;
 632
 633     if (!PIOS_USB_CDC_validate(usb_cdc_dev)) {
 634         return false;
 635     }
 636
 637     if (len > sizeof(usb_cdc_dev->rx_packet_buffer)) {
 638         len = sizeof(usb_cdc_dev->rx_packet_buffer);
 639     }
 640
 641     if (!usb_cdc_dev->rx_in_cb) {
 642         /* No Rx call back registered, disable the receiver */
 643         usb_cdc_dev->rx_active = false;
 644         return false;
 645     }
 646
 647     uint16_t headroom;
 648     bool need_yield = false;
 649     uint16_t bytes_rxed;
 650     bytes_rxed = (usb_cdc_dev->rx_in_cb)(usb_cdc_dev->rx_in_context,
 651                                          usb_cdc_dev->rx_packet_buffer,
 652                                          len,
 653                                          &headroom,
 654                                          &need_yield);
 655
 656     if (bytes_rxed < len) {
 657         /* Lost bytes on rx */
 658         usb_cdc_dev->rx_dropped += (len - bytes_rxed);
 659     }
 660
 661     bool rc;
 662     if (headroom >= sizeof(usb_cdc_dev->rx_packet_buffer)) {
 663         /* We have room for a maximum length message */
 664         PIOS_USBHOOK_EndpointRx(usb_cdc_dev->cfg->data_rx_ep,
 665                                 usb_cdc_dev->rx_packet_buffer,
 666                                 sizeof(usb_cdc_dev->rx_packet_buffer));
 667         rc = true;
 668     } else {
 669         /* Not enough room left for a message, apply backpressure */
 670         usb_cdc_dev->rx_active = false;
 671         rc = false;
 672     }
 673
 674 #if defined(PIOS_INCLUDE_FREERTOS)
 675     if (need_yield) {
 676         vPortYield();
 677     }
 678 #endif /* PIOS_INCLUDE_FREERTOS */
 679
 680     return rc;
 681 }
 682
 683 #endif /* PIOS_INCLUDE_USB_CDC */