Bootloaders/DFU/BootloaderDFU.c

   1 /*
   2              LUFA Library
   3      Copyright (C) Dean Camera, 2018.
   4
   5   dean [at] fourwalledcubicle [dot] com
   6            www.lufa-lib.org
   7 */
   8
   9 /*
  10   Copyright 2018  Dean Camera (dean [at] fourwalledcubicle [dot] com)
  11
  12   Permission to use, copy, modify, distribute, and sell this
  13   software and its documentation for any purpose is hereby granted
  14   without fee, provided that the above copyright notice appear in
  15   all copies and that both that the copyright notice and this
  16   permission notice and warranty disclaimer appear in supporting
  17   documentation, and that the name of the author not be used in
  18   advertising or publicity pertaining to distribution of the
  19   software without specific, written prior permission.
  20
  21   The author disclaims all warranties with regard to this
  22   software, including all implied warranties of merchantability
  23   and fitness.  In no event shall the author be liable for any
  24   special, indirect or consequential damages or any damages
  25   whatsoever resulting from loss of use, data or profits, whether
  26   in an action of contract, negligence or other tortious action,
  27   arising out of or in connection with the use or performance of
  28   this software.
  29 */
  30
  31 /** \file
  32  *
  33  *  Main source file for the DFU class bootloader. This file contains the complete bootloader logic.
  34  */
  35
  36 #define  INCLUDE_FROM_BOOTLOADER_C
  37 #include "BootloaderDFU.h"
  38
  39 /** Flag to indicate if the bootloader is currently running in secure mode, disallowing memory operations
  40  *  other than erase. This is initially set to the value set by SECURE_MODE, and cleared by the bootloader
  41  *  once a memory erase has completed in a bootloader session.
  42  */
  43 static bool IsSecure = SECURE_MODE;
  44
  45 /** Flag to indicate if the bootloader should be running, or should exit and allow the application code to run
  46  *  via a soft reset. When cleared, the bootloader will abort, the USB interface will shut down and the application
  47  *  jumped to via an indirect jump to location 0x0000 (or other location specified by the host).
  48  */
  49 static bool RunBootloader = true;
  50
  51 /** Flag to indicate if the bootloader is waiting to exit. When the host requests the bootloader to exit and
  52  *  jump to the application address it specifies, it sends two sequential commands which must be properly
  53  *  acknowledged. Upon reception of the first the RunBootloader flag is cleared and the WaitForExit flag is set,
  54  *  causing the bootloader to wait for the final exit command before shutting down.
  55  */
  56 static bool WaitForExit = false;
  57
  58 /** Current DFU state machine state, one of the values in the DFU_State_t enum. */
  59 static uint8_t DFU_State = dfuIDLE;
  60
  61 /** Status code of the last executed DFU command. This is set to one of the values in the DFU_Status_t enum after
  62  *  each operation, and returned to the host when a Get Status DFU request is issued.
  63  */
  64 static uint8_t DFU_Status = OK;
  65
  66 /** Data containing the DFU command sent from the host. */
  67 static DFU_Command_t SentCommand;
  68
  69 /** Response to the last issued Read Data DFU command. Unlike other DFU commands, the read command
  70  *  requires a single byte response from the bootloader containing the read data when the next DFU_UPLOAD command
  71  *  is issued by the host.
  72  */
  73 static uint8_t ResponseByte;
  74
  75 /** Pointer to the start of the user application. By default this is 0x0000 (the reset vector), however the host
  76  *  may specify an alternate address when issuing the application soft-start command.
  77  */
  78 static AppPtr_t AppStartPtr = (AppPtr_t)0x0000;
  79
  80 /** 64-bit flash page number. This is concatenated with the current 16-bit address on USB AVRs containing more than
  81  *  64KB of flash memory.
  82  */
  83 static uint8_t Flash64KBPage = 0;
  84
  85 /** Memory start address, indicating the current address in the memory being addressed (either FLASH or EEPROM
  86  *  depending on the issued command from the host).
  87  */
  88 static uint16_t StartAddr = 0x0000;
  89
  90 /** Memory end address, indicating the end address to read from/write to in the memory being addressed (either FLASH
  91  *  of EEPROM depending on the issued command from the host).
  92  */
  93 static uint16_t EndAddr = 0x0000;
  94
  95 /** Magic lock for forced application start. If the HWBE fuse is programmed and BOOTRST is unprogrammed, the bootloader
  96  *  will start if the /HWB line of the AVR is held low and the system is reset. However, if the /HWB line is still held
  97  *  low when the application attempts to start via a watchdog reset, the bootloader will re-start. If set to the value
  98  *  \ref MAGIC_BOOT_KEY the special init function \ref Application_Jump_Check() will force the application to start.
  99  */
 100 uint16_t MagicBootKey ATTR_NO_INIT;
 101
 102
 103 /** Special startup routine to check if the bootloader was started via a watchdog reset, and if the magic application
 104  *  start key has been loaded into \ref MagicBootKey. If the bootloader started via the watchdog and the key is valid,
 105  *  this will force the user application to start via a software jump.
 106  */
 107 void Application_Jump_Check(void)
 108 {
 109         bool JumpToApplication = false;
 110
 111         #if (BOARD == BOARD_LEONARDO)
 112                 /* Enable pull-up on the IO13 pin so we can use it to select the mode */
 113                 PORTC |= (1 << 7);
 114                 Delay_MS(10);
 115
 116                 /* If IO13 is not jumpered to ground, start the user application instead */
 117                 JumpToApplication = ((PINC & (1 << 7)) != 0);
 118
 119                 /* Disable pull-up after the check has completed */
 120                 PORTC &= ~(1 << 7);
 121         #elif ((BOARD == BOARD_XPLAIN) || (BOARD == BOARD_XPLAIN_REV1))
 122                 /* Disable JTAG debugging */
 123                 JTAG_DISABLE();
 124
 125                 /* Enable pull-up on the JTAG TCK pin so we can use it to select the mode */
 126                 PORTF |= (1 << 4);
 127                 Delay_MS(10);
 128
 129                 /* If the TCK pin is not jumpered to ground, start the user application instead */
 130                 JumpToApplication = ((PINF & (1 << 4)) != 0);
 131
 132                 /* Re-enable JTAG debugging */
 133                 JTAG_ENABLE();
 134         #else
 135                 /* Check if the device's BOOTRST fuse is set */
 136                 if (BootloaderAPI_ReadFuse(GET_HIGH_FUSE_BITS) & FUSE_BOOTRST)
 137                 {
 138                         /* If the reset source was not an external reset or the key is correct, clear it and jump to the application */
 139                         if (!(MCUSR & (1 << EXTRF)) || (MagicBootKey == MAGIC_BOOT_KEY))
 140                           JumpToApplication = true;
 141
 142                         /* Clear reset source */
 143                         MCUSR &= ~(1 << EXTRF);
 144                 }
 145                 else
 146                 {
 147                         /* If the reset source was the bootloader and the key is correct, clear it and jump to the application;
 148                          * this can happen in the HWBE fuse is set, and the HBE pin is low during the watchdog reset */
 149                         if ((MCUSR & (1 << WDRF)) && (MagicBootKey == MAGIC_BOOT_KEY))
 150                                 JumpToApplication = true;
 151
 152                         /* Clear reset source */
 153                         MCUSR &= ~(1 << WDRF);
 154                 }
 155         #endif
 156
 157         /* Don't run the user application if the reset vector is blank (no app loaded) */
 158         bool ApplicationValid = (pgm_read_word_near(0) != 0xFFFF);
 159
 160         /* If a request has been made to jump to the user application, honor it */
 161         if (JumpToApplication && ApplicationValid)
 162         {
 163                 /* Turn off the watchdog */
 164                 MCUSR &= ~(1 << WDRF);
 165                 wdt_disable();
 166
 167                 /* Clear the boot key and jump to the user application */
 168                 MagicBootKey = 0;
 169
 170                 // cppcheck-suppress constStatement
 171                 ((void (*)(void))0x0000)();
 172         }
 173 }
 174
 175 /** Main program entry point. This routine configures the hardware required by the bootloader, then continuously
 176  *  runs the bootloader processing routine until instructed to soft-exit, or hard-reset via the watchdog to start
 177  *  the loaded application code.
 178  */
 179 int main(void)
 180 {
 181         /* Configure hardware required by the bootloader */
 182         SetupHardware();
 183
 184         /* Turn on first LED on the board to indicate that the bootloader has started */
 185         LEDs_SetAllLEDs(LEDS_LED1);
 186
 187         /* Enable global interrupts so that the USB stack can function */
 188         GlobalInterruptEnable();
 189
 190         /* Run the USB management task while the bootloader is supposed to be running */
 191         while (RunBootloader || WaitForExit)
 192           USB_USBTask();
 193
 194         /* Reset configured hardware back to their original states for the user application */
 195         ResetHardware();
 196
 197         /* Start the user application */
 198         AppStartPtr();
 199 }
 200
 201 /** Configures all hardware required for the bootloader. */
 202 static void SetupHardware(void)
 203 {
 204         /* Disable watchdog if enabled by bootloader/fuses */
 205         MCUSR &= ~(1 << WDRF);
 206         wdt_disable();
 207
 208         /* Disable clock division */
 209         clock_prescale_set(clock_div_1);
 210
 211         /* Relocate the interrupt vector table to the bootloader section */
 212         MCUCR = (1 << IVCE);
 213         MCUCR = (1 << IVSEL);
 214
 215         /* Initialize the USB and other board hardware drivers */
 216         USB_Init();
 217         LEDs_Init();
 218
 219         /* Bootloader active LED toggle timer initialization */
 220         TIMSK1 = (1 << TOIE1);
 221         TCCR1B = ((1 << CS11) | (1 << CS10));
 222 }
 223
 224 /** Resets all configured hardware required for the bootloader back to their original states. */
 225 static void ResetHardware(void)
 226 {
 227         /* Shut down the USB and other board hardware drivers */
 228         USB_Disable();
 229         LEDs_Disable();
 230
 231         /* Disable Bootloader active LED toggle timer */
 232         TIMSK1 = 0;
 233         TCCR1B = 0;
 234
 235         /* Relocate the interrupt vector table back to the application section */
 236         MCUCR = (1 << IVCE);
 237         MCUCR = 0;
 238 }
 239
 240 /** ISR to periodically toggle the LEDs on the board to indicate that the bootloader is active. */
 241 ISR(TIMER1_OVF_vect, ISR_BLOCK)
 242 {
 243         LEDs_ToggleLEDs(LEDS_LED1 | LEDS_LED2);
 244 }
 245
 246 /** Event handler for the USB_ControlRequest event. This is used to catch and process control requests sent to
 247  *  the device from the USB host before passing along unhandled control requests to the library for processing
 248  *  internally.
 249  */
 250 void EVENT_USB_Device_ControlRequest(void)
 251 {
 252         /* Ignore any requests that aren't directed to the DFU interface */
 253         if ((USB_ControlRequest.bmRequestType & (CONTROL_REQTYPE_TYPE | CONTROL_REQTYPE_RECIPIENT)) !=
 254             (REQTYPE_CLASS | REQREC_INTERFACE))
 255         {
 256                 return;
 257         }
 258
 259         /* Activity - toggle indicator LEDs */
 260         LEDs_ToggleLEDs(LEDS_LED1 | LEDS_LED2);
 261
 262         /* Get the size of the command and data from the wLength value */
 263         SentCommand.DataSize = USB_ControlRequest.wLength;
 264
 265         switch (USB_ControlRequest.bRequest)
 266         {
 267                 case DFU_REQ_DNLOAD:
 268                         Endpoint_ClearSETUP();
 269
 270                         /* Check if bootloader is waiting to terminate */
 271                         if (WaitForExit)
 272                         {
 273                                 /* Bootloader is terminating - process last received command */
 274                                 ProcessBootloaderCommand();
 275
 276                                 /* Indicate that the last command has now been processed - free to exit bootloader */
 277                                 WaitForExit = false;
 278                         }
 279
 280                         /* If the request has a data stage, load it into the command struct */
 281                         if (SentCommand.DataSize)
 282                         {
 283                                 while (!(Endpoint_IsOUTReceived()))
 284                                 {
 285                                         if (USB_DeviceState == DEVICE_STATE_Unattached)
 286                                           return;
 287                                 }
 288
 289                                 /* First byte of the data stage is the DNLOAD request's command */
 290                                 SentCommand.Command = Endpoint_Read_8();
 291
 292                                 /* One byte of the data stage is the command, so subtract it from the total data bytes */
 293                                 SentCommand.DataSize--;
 294
 295                                 /* Load in the rest of the data stage as command parameters */
 296                                 for (uint8_t DataByte = 0; (DataByte < sizeof(SentCommand.Data)) &&
 297                                      Endpoint_BytesInEndpoint(); DataByte++)
 298                                 {
 299                                         SentCommand.Data[DataByte] = Endpoint_Read_8();
 300                                         SentCommand.DataSize--;
 301                                 }
 302
 303                                 /* Process the command */
 304                                 ProcessBootloaderCommand();
 305                         }
 306
 307                         /* Check if currently downloading firmware */
 308                         if (DFU_State == dfuDNLOAD_IDLE)
 309                         {
 310                                 if (!(SentCommand.DataSize))
 311                                 {
 312                                         DFU_State = dfuIDLE;
 313                                 }
 314                                 else
 315                                 {
 316                                         /* Throw away the filler bytes before the start of the firmware */
 317                                         DiscardFillerBytes(DFU_FILLER_BYTES_SIZE);
 318
 319                                         /* Throw away the packet alignment filler bytes before the start of the firmware */
 320                                         DiscardFillerBytes(StartAddr % FIXED_CONTROL_ENDPOINT_SIZE);
 321
 322                                         /* Calculate the number of bytes remaining to be written */
 323                                         uint16_t BytesRemaining = ((EndAddr - StartAddr) + 1);
 324
 325                                         if (IS_ONEBYTE_COMMAND(SentCommand.Data, 0x00))        // Write flash
 326                                         {
 327                                                 /* Calculate the number of words to be written from the number of bytes to be written */
 328                                                 uint16_t WordsRemaining = (BytesRemaining >> 1);
 329
 330                                                 union
 331                                                 {
 332                                                         uint16_t Words[2];
 333                                                         uint32_t Long;
 334                                                 } CurrFlashAddress                 = {.Words = {StartAddr, Flash64KBPage}};
 335
 336                                                 uint32_t CurrFlashPageStartAddress = CurrFlashAddress.Long;
 337                                                 uint8_t  WordsInFlashPage          = 0;
 338
 339                                                 while (WordsRemaining--)
 340                                                 {
 341                                                         /* Check if endpoint is empty - if so clear it and wait until ready for next packet */
 342                                                         if (!(Endpoint_BytesInEndpoint()))
 343                                                         {
 344                                                                 Endpoint_ClearOUT();
 345
 346                                                                 while (!(Endpoint_IsOUTReceived()))
 347                                                                 {
 348                                                                         if (USB_DeviceState == DEVICE_STATE_Unattached)
 349                                                                           return;
 350                                                                 }
 351                                                         }
 352
 353                                                         /* Write the next word into the current flash page */
 354                                                         BootloaderAPI_FillWord(CurrFlashAddress.Long, Endpoint_Read_16_LE());
 355
 356                                                         /* Adjust counters */
 357                                                         WordsInFlashPage      += 1;
 358                                                         CurrFlashAddress.Long += 2;
 359
 360                                                         /* See if an entire page has been written to the flash page buffer */
 361                                                         if ((WordsInFlashPage == (SPM_PAGESIZE >> 1)) || !(WordsRemaining))
 362                                                         {
 363                                                                 /* Commit the flash page to memory */
 364                                                                 BootloaderAPI_WritePage(CurrFlashPageStartAddress);
 365
 366                                                                 /* Check if programming incomplete */
 367                                                                 if (WordsRemaining)
 368                                                                 {
 369                                                                         CurrFlashPageStartAddress = CurrFlashAddress.Long;
 370                                                                         WordsInFlashPage          = 0;
 371
 372                                                                         /* Erase next page's temp buffer */
 373                                                                         BootloaderAPI_ErasePage(CurrFlashAddress.Long);
 374                                                                 }
 375                                                         }
 376                                                 }
 377
 378                                                 /* Once programming complete, start address equals the end address */
 379                                                 StartAddr = EndAddr;
 380                                         }
 381                                         else                                                   // Write EEPROM
 382                                         {
 383                                                 while (BytesRemaining--)
 384                                                 {
 385                                                         /* Check if endpoint is empty - if so clear it and wait until ready for next packet */
 386                                                         if (!(Endpoint_BytesInEndpoint()))
 387                                                         {
 388                                                                 Endpoint_ClearOUT();
 389
 390                                                                 while (!(Endpoint_IsOUTReceived()))
 391                                                                 {
 392                                                                         if (USB_DeviceState == DEVICE_STATE_Unattached)
 393                                                                           return;
 394                                                                 }
 395                                                         }
 396
 397                                                         /* Read the byte from the USB interface and write to to the EEPROM */
 398                                                         eeprom_update_byte((uint8_t*)StartAddr, Endpoint_Read_8());
 399
 400                                                         /* Adjust counters */
 401                                                         StartAddr++;
 402                                                 }
 403                                         }
 404
 405                                         /* Throw away the currently unused DFU file suffix */
 406                                         DiscardFillerBytes(DFU_FILE_SUFFIX_SIZE);
 407                                 }
 408                         }
 409
 410                         Endpoint_ClearOUT();
 411
 412                         Endpoint_ClearStatusStage();
 413
 414                         break;
 415                 case DFU_REQ_UPLOAD:
 416                         Endpoint_ClearSETUP();
 417
 418                         while (!(Endpoint_IsINReady()))
 419                         {
 420                                 if (USB_DeviceState == DEVICE_STATE_Unattached)
 421                                   return;
 422                         }
 423
 424                         if (DFU_State != dfuUPLOAD_IDLE)
 425                         {
 426                                 if ((DFU_State == dfuERROR) && IS_ONEBYTE_COMMAND(SentCommand.Data, 0x01))       // Blank Check
 427                                 {
 428                                         /* Blank checking is performed in the DFU_DNLOAD request - if we get here we've told the host
 429                                            that the memory isn't blank, and the host is requesting the first non-blank address */
 430                                         Endpoint_Write_16_LE(StartAddr);
 431                                 }
 432                                 else
 433                                 {
 434                                         /* Idle state upload - send response to last issued command */
 435                                         Endpoint_Write_8(ResponseByte);
 436                                 }
 437                         }
 438                         else
 439                         {
 440                                 /* Determine the number of bytes remaining in the current block */
 441                                 uint16_t BytesRemaining = ((EndAddr - StartAddr) + 1);
 442
 443                                 if (IS_ONEBYTE_COMMAND(SentCommand.Data, 0x00))            // Read FLASH
 444                                 {
 445                                         /* Calculate the number of words to be written from the number of bytes to be written */
 446                                         uint16_t WordsRemaining = (BytesRemaining >> 1);
 447
 448                                         union
 449                                         {
 450                                                 uint16_t Words[2];
 451                                                 uint32_t Long;
 452                                         } CurrFlashAddress = {.Words = {StartAddr, Flash64KBPage}};
 453
 454                                         while (WordsRemaining--)
 455                                         {
 456                                                 /* Check if endpoint is full - if so clear it and wait until ready for next packet */
 457                                                 if (Endpoint_BytesInEndpoint() == FIXED_CONTROL_ENDPOINT_SIZE)
 458                                                 {
 459                                                         Endpoint_ClearIN();
 460
 461                                                         while (!(Endpoint_IsINReady()))
 462                                                         {
 463                                                                 if (USB_DeviceState == DEVICE_STATE_Unattached)
 464                                                                   return;
 465                                                         }
 466                                                 }
 467
 468                                                 /* Read the flash word and send it via USB to the host */
 469                                                 #if (FLASHEND > 0xFFFF)
 470                                                         Endpoint_Write_16_LE(pgm_read_word_far(CurrFlashAddress.Long));
 471                                                 #else
 472                                                         Endpoint_Write_16_LE(pgm_read_word(CurrFlashAddress.Long));
 473                                                 #endif
 474
 475                                                 /* Adjust counters */
 476                                                 CurrFlashAddress.Long += 2;
 477                                         }
 478
 479                                         /* Once reading is complete, start address equals the end address */
 480                                         StartAddr = EndAddr;
 481                                 }
 482                                 else if (IS_ONEBYTE_COMMAND(SentCommand.Data, 0x02))       // Read EEPROM
 483                                 {
 484                                         while (BytesRemaining--)
 485                                         {
 486                                                 /* Check if endpoint is full - if so clear it and wait until ready for next packet */
 487                                                 if (Endpoint_BytesInEndpoint() == FIXED_CONTROL_ENDPOINT_SIZE)
 488                                                 {
 489                                                         Endpoint_ClearIN();
 490
 491                                                         while (!(Endpoint_IsINReady()))
 492                                                         {
 493                                                                 if (USB_DeviceState == DEVICE_STATE_Unattached)
 494                                                                   return;
 495                                                         }
 496                                                 }
 497
 498                                                 /* Read the EEPROM byte and send it via USB to the host */
 499                                                 Endpoint_Write_8(eeprom_read_byte((uint8_t*)StartAddr));
 500
 501                                                 /* Adjust counters */
 502                                                 StartAddr++;
 503                                         }
 504                                 }
 505
 506                                 /* Return to idle state */
 507                                 DFU_State = dfuIDLE;
 508                         }
 509
 510                         Endpoint_ClearIN();
 511
 512                         Endpoint_ClearStatusStage();
 513                         break;
 514                 case DFU_REQ_GETSTATUS:
 515                         Endpoint_ClearSETUP();
 516
 517                         while (!(Endpoint_IsINReady()))
 518                         {
 519                                 if (USB_DeviceState == DEVICE_STATE_Unattached)
 520                                   return;
 521                         }
 522
 523                         /* Write 8-bit status value */
 524                         Endpoint_Write_8(DFU_Status);
 525
 526                         /* Write 24-bit poll timeout value */
 527                         Endpoint_Write_8(0);
 528                         Endpoint_Write_16_LE(0);
 529
 530                         /* Write 8-bit state value */
 531                         Endpoint_Write_8(DFU_State);
 532
 533                         /* Write 8-bit state string ID number */
 534                         Endpoint_Write_8(0);
 535
 536                         Endpoint_ClearIN();
 537
 538                         Endpoint_ClearStatusStage();
 539                         break;
 540                 case DFU_REQ_CLRSTATUS:
 541                         Endpoint_ClearSETUP();
 542
 543                         /* Reset the status value variable to the default OK status */
 544                         DFU_Status = OK;
 545
 546                         Endpoint_ClearStatusStage();
 547                         break;
 548                 case DFU_REQ_GETSTATE:
 549                         Endpoint_ClearSETUP();
 550
 551                         while (!(Endpoint_IsINReady()))
 552                         {
 553                                 if (USB_DeviceState == DEVICE_STATE_Unattached)
 554                                   return;
 555                         }
 556
 557                         /* Write the current device state to the endpoint */
 558                         Endpoint_Write_8(DFU_State);
 559
 560                         Endpoint_ClearIN();
 561
 562                         Endpoint_ClearStatusStage();
 563                         break;
 564                 case DFU_REQ_ABORT:
 565                         Endpoint_ClearSETUP();
 566
 567                         /* Reset the current state variable to the default idle state */
 568                         DFU_State = dfuIDLE;
 569
 570                         Endpoint_ClearStatusStage();
 571                         break;
 572         }
 573 }
 574
 575 /** Routine to discard the specified number of bytes from the control endpoint stream. This is used to
 576  *  discard unused bytes in the stream from the host, including the memory program block suffix.
 577  *
 578  *  \param[in] NumberOfBytes  Number of bytes to discard from the host from the control endpoint
 579  */
 580 static void DiscardFillerBytes(uint8_t NumberOfBytes)
 581 {
 582         while (NumberOfBytes--)
 583         {
 584                 if (!(Endpoint_BytesInEndpoint()))
 585                 {
 586                         Endpoint_ClearOUT();
 587
 588                         /* Wait until next data packet received */
 589                         while (!(Endpoint_IsOUTReceived()))
 590                         {
 591                                 if (USB_DeviceState == DEVICE_STATE_Unattached)
 592                                   return;
 593                         }
 594                 }
 595                 else
 596                 {
 597                         Endpoint_Discard_8();
 598                 }
 599         }
 600 }
 601
 602 /** Routine to process an issued command from the host, via a DFU_DNLOAD request wrapper. This routine ensures
 603  *  that the command is allowed based on the current secure mode flag value, and passes the command off to the
 604  *  appropriate handler function.
 605  */
 606 static void ProcessBootloaderCommand(void)
 607 {
 608         /* Check if device is in secure mode */
 609         if (IsSecure)
 610         {
 611                 /* Don't process command unless it is a READ or chip erase command */
 612                 if (!(((SentCommand.Command == COMMAND_WRITE)             &&
 613                         IS_TWOBYTE_COMMAND(SentCommand.Data, 0x00, 0xFF)) ||
 614                            (SentCommand.Command == COMMAND_READ)))
 615                 {
 616                         /* Set the state and status variables to indicate the error */
 617                         DFU_State  = dfuERROR;
 618                         DFU_Status = errWRITE;
 619
 620                         /* Stall command */
 621                         Endpoint_StallTransaction();
 622
 623                         /* Don't process the command */
 624                         return;
 625                 }
 626         }
 627
 628         /* Dispatch the required command processing routine based on the command type */
 629         switch (SentCommand.Command)
 630         {
 631                 case COMMAND_PROG_START:
 632                         ProcessMemProgCommand();
 633                         break;
 634                 case COMMAND_DISP_DATA:
 635                         ProcessMemReadCommand();
 636                         break;
 637                 case COMMAND_WRITE:
 638                         ProcessWriteCommand();
 639                         break;
 640                 case COMMAND_READ:
 641                         ProcessReadCommand();
 642                         break;
 643                 case COMMAND_CHANGE_BASE_ADDR:
 644                         if (IS_TWOBYTE_COMMAND(SentCommand.Data, 0x03, 0x00))              // Set 64KB flash page command
 645                           Flash64KBPage = SentCommand.Data[2];
 646
 647                         break;
 648         }
 649 }
 650
 651 /** Routine to concatenate the given pair of 16-bit memory start and end addresses from the host, and store them
 652  *  in the StartAddr and EndAddr global variables.
 653  */
 654 static void LoadStartEndAddresses(void)
 655 {
 656         union
 657         {
 658                 uint8_t  Bytes[2];
 659                 uint16_t Word;
 660         } Address[2] = {{.Bytes = {SentCommand.Data[2], SentCommand.Data[1]}},
 661                         {.Bytes = {SentCommand.Data[4], SentCommand.Data[3]}}};
 662
 663         /* Load in the start and ending read addresses from the sent data packet */
 664         StartAddr = Address[0].Word;
 665         EndAddr   = Address[1].Word;
 666 }
 667
 668 /** Handler for a Memory Program command issued by the host. This routine handles the preparations needed
 669  *  to write subsequent data from the host into the specified memory.
 670  */
 671 static void ProcessMemProgCommand(void)
 672 {
 673         if (IS_ONEBYTE_COMMAND(SentCommand.Data, 0x00) ||                          // Write FLASH command
 674             IS_ONEBYTE_COMMAND(SentCommand.Data, 0x01))                            // Write EEPROM command
 675         {
 676                 /* Load in the start and ending read addresses */
 677                 LoadStartEndAddresses();
 678
 679                 /* If FLASH is being written to, we need to pre-erase the first page to write to */
 680                 if (IS_ONEBYTE_COMMAND(SentCommand.Data, 0x00))
 681                 {
 682                         union
 683                         {
 684                                 uint16_t Words[2];
 685                                 uint32_t Long;
 686                         } CurrFlashAddress = {.Words = {StartAddr, Flash64KBPage}};
 687
 688                         /* Erase the current page's temp buffer */
 689                         BootloaderAPI_ErasePage(CurrFlashAddress.Long);
 690                 }
 691
 692                 /* Set the state so that the next DNLOAD requests reads in the firmware */
 693                 DFU_State = dfuDNLOAD_IDLE;
 694         }
 695 }
 696
 697 /** Handler for a Memory Read command issued by the host. This routine handles the preparations needed
 698  *  to read subsequent data from the specified memory out to the host, as well as implementing the memory
 699  *  blank check command.
 700  */
 701 static void ProcessMemReadCommand(void)
 702 {
 703         if (IS_ONEBYTE_COMMAND(SentCommand.Data, 0x00) ||                          // Read FLASH command
 704         IS_ONEBYTE_COMMAND(SentCommand.Data, 0x02))                            // Read EEPROM command
 705         {
 706                 /* Load in the start and ending read addresses */
 707                 LoadStartEndAddresses();
 708
 709                 /* Set the state so that the next UPLOAD requests read out the firmware */
 710                 DFU_State = dfuUPLOAD_IDLE;
 711         }
 712         else if (IS_ONEBYTE_COMMAND(SentCommand.Data, 0x01))                       // Blank check FLASH command
 713         {
 714                 uint32_t CurrFlashAddress = 0;
 715
 716                 while (CurrFlashAddress < (uint32_t)BOOT_START_ADDR)
 717                 {
 718                         /* Check if the current byte is not blank */
 719                         #if (FLASHEND > 0xFFFF)
 720                         if (pgm_read_byte_far(CurrFlashAddress) != 0xFF)
 721                         #else
 722                         if (pgm_read_byte(CurrFlashAddress) != 0xFF)
 723                         #endif
 724                         {
 725                                 /* Save the location of the first non-blank byte for response back to the host */
 726                                 Flash64KBPage = (CurrFlashAddress >> 16);
 727                                 StartAddr     = CurrFlashAddress;
 728
 729                                 /* Set state and status variables to the appropriate error values */
 730                                 DFU_State  = dfuERROR;
 731                                 DFU_Status = errCHECK_ERASED;
 732
 733                                 break;
 734                         }
 735
 736                         CurrFlashAddress++;
 737                 }
 738         }
 739 }
 740
 741 /** Handler for a Data Write command issued by the host. This routine handles non-programming commands such as
 742  *  bootloader exit (both via software jumps and hardware watchdog resets) and flash memory erasure.
 743  */
 744 static void ProcessWriteCommand(void)
 745 {
 746         if (IS_ONEBYTE_COMMAND(SentCommand.Data, 0x03))                            // Start application
 747         {
 748                 /* Indicate that the bootloader is terminating */
 749                 WaitForExit = true;
 750
 751                 /* Check if data supplied for the Start Program command - no data executes the program */
 752                 if (SentCommand.DataSize)
 753                 {
 754                         if (SentCommand.Data[1] == 0x01)                                   // Start via jump
 755                         {
 756                                 union
 757                                 {
 758                                         uint8_t  Bytes[2];
 759                                         AppPtr_t FuncPtr;
 760                                 } Address = {.Bytes = {SentCommand.Data[4], SentCommand.Data[3]}};
 761
 762                                 /* Load in the jump address into the application start address pointer */
 763                                 AppStartPtr = Address.FuncPtr;
 764                         }
 765                 }
 766                 else
 767                 {
 768                         if (SentCommand.Data[1] == 0x00)                                   // Start via watchdog
 769                         {
 770                                 /* Unlock the forced application start mode of the bootloader if it is restarted */
 771                                 MagicBootKey = MAGIC_BOOT_KEY;
 772
 773                                 /* Start the watchdog to reset the AVR once the communications are finalized */
 774                                 wdt_enable(WDTO_250MS);
 775                         }
 776                         else                                                               // Start via jump
 777                         {
 778                                 /* Set the flag to terminate the bootloader at next opportunity if a valid application has been loaded */
 779                                 if (pgm_read_word_near(0) == 0xFFFF)
 780                                   RunBootloader = false;
 781                         }
 782                 }
 783         }
 784         else if (IS_TWOBYTE_COMMAND(SentCommand.Data, 0x00, 0xFF))                 // Erase flash
 785         {
 786                 /* Clear the application section of flash */
 787                 for (uint32_t CurrFlashAddress = 0; CurrFlashAddress < (uint32_t)BOOT_START_ADDR; CurrFlashAddress += SPM_PAGESIZE)
 788                         BootloaderAPI_ErasePage(CurrFlashAddress);
 789
 790                 /* Memory has been erased, reset the security bit so that programming/reading is allowed */
 791                 IsSecure = false;
 792         }
 793 }
 794
 795 /** Handler for a Data Read command issued by the host. This routine handles bootloader information retrieval
 796  *  commands such as device signature and bootloader version retrieval.
 797  */
 798 static void ProcessReadCommand(void)
 799 {
 800         const uint8_t BootloaderInfo[3] = {BOOTLOADER_VERSION, BOOTLOADER_ID_BYTE1, BOOTLOADER_ID_BYTE2};
 801         const uint8_t SignatureInfo[4]  = {0x58, AVR_SIGNATURE_1, AVR_SIGNATURE_2, AVR_SIGNATURE_3};
 802
 803         uint8_t DataIndexToRead    = SentCommand.Data[1];
 804         bool    ReadAddressInvalid = false;
 805
 806         if (IS_ONEBYTE_COMMAND(SentCommand.Data, 0x00))                        // Read bootloader info
 807         {
 808                 if (DataIndexToRead < 3)
 809                   ResponseByte = BootloaderInfo[DataIndexToRead];
 810                 else
 811                   ReadAddressInvalid = true;
 812         }
 813         else if (IS_ONEBYTE_COMMAND(SentCommand.Data, 0x01))                    // Read signature byte
 814         {
 815                 switch (DataIndexToRead)
 816                 {
 817                         case 0x30:
 818                                 ResponseByte = SignatureInfo[0];
 819                                 break;
 820                         case 0x31:
 821                                 ResponseByte = SignatureInfo[1];
 822                                 break;
 823                         case 0x60:
 824                                 ResponseByte = SignatureInfo[2];
 825                                 break;
 826                         case 0x61:
 827                                 ResponseByte = SignatureInfo[3];
 828                                 break;
 829                         default:
 830                                 ReadAddressInvalid = true;
 831                                 break;
 832                 }
 833         }
 834
 835         if (ReadAddressInvalid)
 836         {
 837                 /* Set the state and status variables to indicate the error */
 838                 DFU_State  = dfuERROR;
 839                 DFU_Status = errADDRESS;
 840         }
 841 }