BootloaderDFU.c 22.7 KB
Newer Older
1
2
/*
             LUFA Library
3
     Copyright (C) Dean Camera, 2011.
4

5
  dean [at] fourwalledcubicle [dot] com
6
           www.lufa-lib.org
7
8
9
*/

/*
10
  Copyright 2011  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
17
18
  permission notice and warranty disclaimer appear in supporting
  documentation, and that the name of the author not be used in
  advertising or publicity pertaining to distribution of the
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
  software without specific, written prior permission.

  The author disclaim all warranties with regard to this
  software, including all implied warranties of merchantability
  and fitness.  In no event shall the author be liable for any
  special, indirect or consequential damages or any damages
  whatsoever resulting from loss of use, data or profits, whether
  in an action of contract, negligence or other tortious action,
  arising out of or in connection with the use or performance of
  this software.
*/

/** \file
 *
 *  Main source file for the DFU class bootloader. This file contains the complete bootloader logic.
 */

#define  INCLUDE_FROM_BOOTLOADER_C
#include "BootloaderDFU.h"

/** Flag to indicate if the bootloader is currently running in secure mode, disallowing memory operations
 *  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
46
47
48

/** Flag to indicate if the bootloader should be running, or should exit and allow the application code to run
 *  via a soft reset. When cleared, the bootloader will abort, the USB interface will shut down and the application
 *  jumped to via an indirect jump to location 0x0000 (or other location specified by the host).
 */
49
static bool RunBootloader = true;
50
51
52
53
54
55

/** Flag to indicate if the bootloader is waiting to exit. When the host requests the bootloader to exit and
 *  jump to the application address it specifies, it sends two sequential commands which must be properly
 *  acknowledged. Upon reception of the first the RunBootloader flag is cleared and the WaitForExit flag is set,
 *  causing the bootloader to wait for the final exit command before shutting down.
 */
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
62
63

/** Status code of the last executed DFU command. This is set to one of the values in the DFU_Status_t enum after
 *  each operation, and returned to the host when a Get Status DFU request is issued.
 */
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
70
71
72

/** Response to the last issued Read Data DFU command. Unlike other DFU commands, the read command
 *  requires a single byte response from the bootloader containing the read data when the next DFU_UPLOAD command
 *  is issued by the host.
 */
73
static uint8_t ResponseByte;
74
75
76
77

/** Pointer to the start of the user application. By default this is 0x0000 (the reset vector), however the host
 *  may specify an alternate address when issuing the application soft-start command.
 */
78
static AppPtr_t AppStartPtr = (AppPtr_t)0x0000;
79
80
81
82

/** 64-bit flash page number. This is concatenated with the current 16-bit address on USB AVRs containing more than
 *  64KB of flash memory.
 */
83
static uint8_t Flash64KBPage = 0;
84
85
86
87

/** Memory start address, indicating the current address in the memory being addressed (either FLASH or EEPROM
 *  depending on the issued command from the host).
 */
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
92
 *  of EEPROM depending on the issued command from the host).
 */
93
static uint16_t EndAddr = 0x0000;
94
95


96
/** Main program entry point. This routine configures the hardware required by the bootloader, then continuously
97
98
99
100
101
102
103
 *  runs the bootloader processing routine until instructed to soft-exit, or hard-reset via the watchdog to start
 *  the loaded application code.
 */
int main(void)
{
	/* Configure hardware required by the bootloader */
	SetupHardware();
104

105
106
107
108
109
110
111
	#if ((BOARD == BOARD_XPLAIN) || (BOARD == BOARD_XPLAIN_REV1))
	/* Disable JTAG debugging */
	MCUCR |= (1 << JTD);
	MCUCR |= (1 << JTD);

	/* Enable pull-up on the JTAG TCK pin so we can use it to select the mode */
	PORTF |= (1 << 4);
112
	Delay_MS(10);
113
114
115

	/* If the TCK pin is not jumpered to ground, start the user application instead */
	RunBootloader = (!(PINF & (1 << 4)));
116

117
118
	/* Re-enable JTAG debugging */
	MCUCR &= ~(1 << JTD);
119
	MCUCR &= ~(1 << JTD);
120
121
	#endif

122
123
124
	/* Turn on first LED on the board to indicate that the bootloader has started */
	LEDs_SetAllLEDs(LEDS_LED1);

125
126
127
128
129
130
	/* Enable global interrupts so that the USB stack can function */
	sei();

	/* Run the USB management task while the bootloader is supposed to be running */
	while (RunBootloader || WaitForExit)
	  USB_USBTask();
131

132
133
	/* Reset configured hardware back to their original states for the user application */
	ResetHardware();
134

135
136
137
138
139
	/* Start the user application */
	AppStartPtr();
}

/** Configures all hardware required for the bootloader. */
140
static void SetupHardware(void)
141
142
143
144
145
146
147
{
	/* Disable watchdog if enabled by bootloader/fuses */
	MCUSR &= ~(1 << WDRF);
	wdt_disable();

	/* Disable clock division */
	clock_prescale_set(clock_div_1);
148

149
150
151
152
	/* Relocate the interrupt vector table to the bootloader section */
	MCUCR = (1 << IVCE);
	MCUCR = (1 << IVSEL);

153
	/* Initialize the USB and other board hardware drivers */
154
	USB_Init();
155
	LEDs_Init();
156

157
158
159
	/* Bootloader active LED toggle timer initialization */
	TIMSK1 = (1 << TOIE1);
	TCCR1B = ((1 << CS11) | (1 << CS10));
160
161
162
}

/** Resets all configured hardware required for the bootloader back to their original states. */
163
static void ResetHardware(void)
164
{
165
	/* Shut down the USB and other board hardware drivers */
166
	USB_Disable();
167
	LEDs_Disable();
168

169
170
171
172
173
	/* Relocate the interrupt vector table back to the application section */
	MCUCR = (1 << IVCE);
	MCUCR = 0;
}

174
175
176
177
178
179
/** ISR to periodically toggle the LEDs on the board to indicate that the bootloader is active. */
ISR(TIMER1_OVF_vect, ISR_BLOCK)
{
	LEDs_ToggleLEDs(LEDS_LED1 | LEDS_LED2);
}

180
181
182
/** Event handler for the USB_ControlRequest event. This is used to catch and process control requests sent to
 *  the device from the USB host before passing along unhandled control requests to the library for processing
 *  internally.
183
 */
184
void EVENT_USB_Device_ControlRequest(void)
185
{
186
187
188
189
190
191
	/* Ignore any requests that aren't directed to the DFU interface */
	if ((USB_ControlRequest.bmRequestType & (CONTROL_REQTYPE_TYPE | CONTROL_REQTYPE_RECIPIENT)) !=
	    (REQTYPE_CLASS | REQREC_INTERFACE))
	{
		return;
	}
192

193
194
195
196
197
198
	/* Activity - toggle indicator LEDs */
	LEDs_ToggleLEDs(LEDS_LED1 | LEDS_LED2);

	/* Get the size of the command and data from the wLength value */
	SentCommand.DataSize = USB_ControlRequest.wLength;

199
200
	switch (USB_ControlRequest.bRequest)
	{
201
		case DFU_REQ_DNLOAD:
202
			Endpoint_ClearSETUP();
203

204
205
206
207
208
			/* Check if bootloader is waiting to terminate */
			if (WaitForExit)
			{
				/* Bootloader is terminating - process last received command */
				ProcessBootloaderCommand();
209

210
211
212
				/* Indicate that the last command has now been processed - free to exit bootloader */
				WaitForExit = false;
			}
213

214
215
216
217
			/* If the request has a data stage, load it into the command struct */
			if (SentCommand.DataSize)
			{
				while (!(Endpoint_IsOUTReceived()))
218
				{
219
220
221
222
223
					if (USB_DeviceState == DEVICE_STATE_Unattached)
					  return;
				}

				/* First byte of the data stage is the DNLOAD request's command */
224
				SentCommand.Command = Endpoint_Read_8();
225

226
227
				/* One byte of the data stage is the command, so subtract it from the total data bytes */
				SentCommand.DataSize--;
228

229
230
231
232
				/* Load in the rest of the data stage as command parameters */
				for (uint8_t DataByte = 0; (DataByte < sizeof(SentCommand.Data)) &&
				     Endpoint_BytesInEndpoint(); DataByte++)
				{
233
					SentCommand.Data[DataByte] = Endpoint_Read_8();
234
235
					SentCommand.DataSize--;
				}
236

237
238
239
				/* Process the command */
				ProcessBootloaderCommand();
			}
240

241
242
			/* Check if currently downloading firmware */
			if (DFU_State == dfuDNLOAD_IDLE)
243
			{
244
245
246
247
248
249
250
251
252
253
254
				if (!(SentCommand.DataSize))
				{
					DFU_State = dfuIDLE;
				}
				else
				{
					/* Throw away the filler bytes before the start of the firmware */
					DiscardFillerBytes(DFU_FILLER_BYTES_SIZE);

					/* Throw away the packet alignment filler bytes before the start of the firmware */
					DiscardFillerBytes(StartAddr % FIXED_CONTROL_ENDPOINT_SIZE);
255

256
257
					/* Calculate the number of bytes remaining to be written */
					uint16_t BytesRemaining = ((EndAddr - StartAddr) + 1);
258

259
260
261
262
					if (IS_ONEBYTE_COMMAND(SentCommand.Data, 0x00))        // Write flash
					{
						/* Calculate the number of words to be written from the number of bytes to be written */
						uint16_t WordsRemaining = (BytesRemaining >> 1);
263

264
265
266
267
268
						union
						{
							uint16_t Words[2];
							uint32_t Long;
						} CurrFlashAddress                 = {.Words = {StartAddr, Flash64KBPage}};
269

270
271
272
273
274
275
276
277
278
279
280
						uint32_t CurrFlashPageStartAddress = CurrFlashAddress.Long;
						uint8_t  WordsInFlashPage          = 0;

						while (WordsRemaining--)
						{
							/* Check if endpoint is empty - if so clear it and wait until ready for next packet */
							if (!(Endpoint_BytesInEndpoint()))
							{
								Endpoint_ClearOUT();

								while (!(Endpoint_IsOUTReceived()))
281
								{
282
283
284
285
286
287
									if (USB_DeviceState == DEVICE_STATE_Unattached)
									  return;
								}
							}

							/* Write the next word into the current flash page */
288
							boot_page_fill(CurrFlashAddress.Long, Endpoint_Read_16_LE());
289
290
291
292
293
294
295
296
297
298
299

							/* Adjust counters */
							WordsInFlashPage      += 1;
							CurrFlashAddress.Long += 2;

							/* See if an entire page has been written to the flash page buffer */
							if ((WordsInFlashPage == (SPM_PAGESIZE >> 1)) || !(WordsRemaining))
							{
								/* Commit the flash page to memory */
								boot_page_write(CurrFlashPageStartAddress);
								boot_spm_busy_wait();
300

301
302
303
304
305
306
307
308
309
310
311
312
								/* Check if programming incomplete */
								if (WordsRemaining)
								{
									CurrFlashPageStartAddress = CurrFlashAddress.Long;
									WordsInFlashPage          = 0;

									/* Erase next page's temp buffer */
									boot_page_erase(CurrFlashAddress.Long);
									boot_spm_busy_wait();
								}
							}
						}
313

314
315
						/* Once programming complete, start address equals the end address */
						StartAddr = EndAddr;
316

317
318
319
320
321
322
323
324
325
326
327
328
329
						/* Re-enable the RWW section of flash */
						boot_rww_enable();
					}
					else                                                   // Write EEPROM
					{
						while (BytesRemaining--)
						{
							/* Check if endpoint is empty - if so clear it and wait until ready for next packet */
							if (!(Endpoint_BytesInEndpoint()))
							{
								Endpoint_ClearOUT();

								while (!(Endpoint_IsOUTReceived()))
330
								{
331
332
333
334
335
336
									if (USB_DeviceState == DEVICE_STATE_Unattached)
									  return;
								}
							}

							/* Read the byte from the USB interface and write to to the EEPROM */
337
							eeprom_write_byte((uint8_t*)StartAddr, Endpoint_Read_8());
338

339
340
341
342
							/* Adjust counters */
							StartAddr++;
						}
					}
343

344
345
346
347
348
349
350
351
352
353
					/* Throw away the currently unused DFU file suffix */
					DiscardFillerBytes(DFU_FILE_SUFFIX_SIZE);
				}
			}

			Endpoint_ClearOUT();

			Endpoint_ClearStatusStage();

			break;
354
		case DFU_REQ_UPLOAD:
355
356
357
			Endpoint_ClearSETUP();

			while (!(Endpoint_IsINReady()))
358
			{
359
360
361
				if (USB_DeviceState == DEVICE_STATE_Unattached)
				  return;
			}
362

363
364
365
366
367
368
			if (DFU_State != dfuUPLOAD_IDLE)
			{
				if ((DFU_State == dfuERROR) && IS_ONEBYTE_COMMAND(SentCommand.Data, 0x01))       // Blank Check
				{
					/* Blank checking is performed in the DFU_DNLOAD request - if we get here we've told the host
					   that the memory isn't blank, and the host is requesting the first non-blank address */
369
					Endpoint_Write_16_LE(StartAddr);
370
371
372
373
				}
				else
				{
					/* Idle state upload - send response to last issued command */
374
					Endpoint_Write_8(ResponseByte);
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
				}
			}
			else
			{
				/* Determine the number of bytes remaining in the current block */
				uint16_t BytesRemaining = ((EndAddr - StartAddr) + 1);

				if (IS_ONEBYTE_COMMAND(SentCommand.Data, 0x00))            // Read FLASH
				{
					/* Calculate the number of words to be written from the number of bytes to be written */
					uint16_t WordsRemaining = (BytesRemaining >> 1);

					union
					{
						uint16_t Words[2];
						uint32_t Long;
					} CurrFlashAddress = {.Words = {StartAddr, Flash64KBPage}};

					while (WordsRemaining--)
					{
						/* Check if endpoint is full - if so clear it and wait until ready for next packet */
						if (Endpoint_BytesInEndpoint() == FIXED_CONTROL_ENDPOINT_SIZE)
						{
							Endpoint_ClearIN();

							while (!(Endpoint_IsINReady()))
401
							{
402
403
404
405
406
407
408
								if (USB_DeviceState == DEVICE_STATE_Unattached)
								  return;
							}
						}

						/* Read the flash word and send it via USB to the host */
						#if (FLASHEND > 0xFFFF)
409
							Endpoint_Write_16_LE(pgm_read_word_far(CurrFlashAddress.Long));
410
						#else
411
							Endpoint_Write_16_LE(pgm_read_word(CurrFlashAddress.Long));
412
413
414
415
416
						#endif

						/* Adjust counters */
						CurrFlashAddress.Long += 2;
					}
417

418
419
420
421
422
423
424
425
426
427
428
					/* Once reading is complete, start address equals the end address */
					StartAddr = EndAddr;
				}
				else if (IS_ONEBYTE_COMMAND(SentCommand.Data, 0x02))       // Read EEPROM
				{
					while (BytesRemaining--)
					{
						/* Check if endpoint is full - if so clear it and wait until ready for next packet */
						if (Endpoint_BytesInEndpoint() == FIXED_CONTROL_ENDPOINT_SIZE)
						{
							Endpoint_ClearIN();
429

430
							while (!(Endpoint_IsINReady()))
431
							{
432
433
434
435
436
437
								if (USB_DeviceState == DEVICE_STATE_Unattached)
								  return;
							}
						}

						/* Read the EEPROM byte and send it via USB to the host */
438
						Endpoint_Write_8(eeprom_read_byte((uint8_t*)StartAddr));
439
440
441
442
443
444
445
446
447
448
449
450
451
452

						/* Adjust counters */
						StartAddr++;
					}
				}

				/* Return to idle state */
				DFU_State = dfuIDLE;
			}

			Endpoint_ClearIN();

			Endpoint_ClearStatusStage();
			break;
453
		case DFU_REQ_GETSTATUS:
454
			Endpoint_ClearSETUP();
455

456
			/* Write 8-bit status value */
457
			Endpoint_Write_8(DFU_Status);
458

459
			/* Write 24-bit poll timeout value */
460
461
			Endpoint_Write_8(0);
			Endpoint_Write_16_LE(0);
462

463
			/* Write 8-bit state value */
464
			Endpoint_Write_8(DFU_State);
465
466

			/* Write 8-bit state string ID number */
467
			Endpoint_Write_8(0);
468
469

			Endpoint_ClearIN();
470

471
			Endpoint_ClearStatusStage();
472
			break;
473
		case DFU_REQ_CLRSTATUS:
474
			Endpoint_ClearSETUP();
475

476
477
478
479
480
			/* Reset the status value variable to the default OK status */
			DFU_Status = OK;

			Endpoint_ClearStatusStage();
			break;
481
		case DFU_REQ_GETSTATE:
482
			Endpoint_ClearSETUP();
483

484
			/* Write the current device state to the endpoint */
485
			Endpoint_Write_8(DFU_State);
486

487
			Endpoint_ClearIN();
488

489
490
			Endpoint_ClearStatusStage();
			break;
491
		case DFU_REQ_ABORT:
492
			Endpoint_ClearSETUP();
493

494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
			/* Reset the current state variable to the default idle state */
			DFU_State = dfuIDLE;

			Endpoint_ClearStatusStage();
			break;
	}
}

/** Routine to discard the specified number of bytes from the control endpoint stream. This is used to
 *  discard unused bytes in the stream from the host, including the memory program block suffix.
 *
 *  \param[in] NumberOfBytes  Number of bytes to discard from the host from the control endpoint
 */
static void DiscardFillerBytes(uint8_t NumberOfBytes)
{
	while (NumberOfBytes--)
	{
		if (!(Endpoint_BytesInEndpoint()))
		{
			Endpoint_ClearOUT();

			/* Wait until next data packet received */
			while (!(Endpoint_IsOUTReceived()))
517
			{
518
519
520
521
522
523
				if (USB_DeviceState == DEVICE_STATE_Unattached)
				  return;
			}
		}
		else
		{
524
			Endpoint_Discard_8();
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
		}
	}
}

/** Routine to process an issued command from the host, via a DFU_DNLOAD request wrapper. This routine ensures
 *  that the command is allowed based on the current secure mode flag value, and passes the command off to the
 *  appropriate handler function.
 */
static void ProcessBootloaderCommand(void)
{
	/* Check if device is in secure mode */
	if (IsSecure)
	{
		/* Don't process command unless it is a READ or chip erase command */
		if (!(((SentCommand.Command == COMMAND_WRITE)             &&
		        IS_TWOBYTE_COMMAND(SentCommand.Data, 0x00, 0xFF)) ||
			   (SentCommand.Command == COMMAND_READ)))
		{
			/* Set the state and status variables to indicate the error */
			DFU_State  = dfuERROR;
			DFU_Status = errWRITE;
546

547
548
			/* Stall command */
			Endpoint_StallTransaction();
549

550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
			/* Don't process the command */
			return;
		}
	}

	/* Dispatch the required command processing routine based on the command type */
	switch (SentCommand.Command)
	{
		case COMMAND_PROG_START:
			ProcessMemProgCommand();
			break;
		case COMMAND_DISP_DATA:
			ProcessMemReadCommand();
			break;
		case COMMAND_WRITE:
			ProcessWriteCommand();
			break;
		case COMMAND_READ:
			ProcessReadCommand();
			break;
		case COMMAND_CHANGE_BASE_ADDR:
			if (IS_TWOBYTE_COMMAND(SentCommand.Data, 0x03, 0x00))              // Set 64KB flash page command
			  Flash64KBPage = SentCommand.Data[2];

			break;
	}
}

/** Routine to concatenate the given pair of 16-bit memory start and end addresses from the host, and store them
 *  in the StartAddr and EndAddr global variables.
 */
static void LoadStartEndAddresses(void)
{
	union
	{
		uint8_t  Bytes[2];
		uint16_t Word;
	} Address[2] = {{.Bytes = {SentCommand.Data[2], SentCommand.Data[1]}},
	                {.Bytes = {SentCommand.Data[4], SentCommand.Data[3]}}};
589

590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
	/* Load in the start and ending read addresses from the sent data packet */
	StartAddr = Address[0].Word;
	EndAddr   = Address[1].Word;
}

/** Handler for a Memory Program command issued by the host. This routine handles the preparations needed
 *  to write subsequent data from the host into the specified memory.
 */
static void ProcessMemProgCommand(void)
{
	if (IS_ONEBYTE_COMMAND(SentCommand.Data, 0x00) ||                          // Write FLASH command
	    IS_ONEBYTE_COMMAND(SentCommand.Data, 0x01))                            // Write EEPROM command
	{
		/* Load in the start and ending read addresses */
		LoadStartEndAddresses();
605

606
607
608
609
610
611
612
613
		/* If FLASH is being written to, we need to pre-erase the first page to write to */
		if (IS_ONEBYTE_COMMAND(SentCommand.Data, 0x00))
		{
			union
			{
				uint16_t Words[2];
				uint32_t Long;
			} CurrFlashAddress = {.Words = {StartAddr, Flash64KBPage}};
614

615
616
617
618
			/* Erase the current page's temp buffer */
			boot_page_erase(CurrFlashAddress.Long);
			boot_spm_busy_wait();
		}
619

620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
		/* Set the state so that the next DNLOAD requests reads in the firmware */
		DFU_State = dfuDNLOAD_IDLE;
	}
}

/** Handler for a Memory Read command issued by the host. This routine handles the preparations needed
 *  to read subsequent data from the specified memory out to the host, as well as implementing the memory
 *  blank check command.
 */
static void ProcessMemReadCommand(void)
{
	if (IS_ONEBYTE_COMMAND(SentCommand.Data, 0x00) ||                          // Read FLASH command
        IS_ONEBYTE_COMMAND(SentCommand.Data, 0x02))                            // Read EEPROM command
	{
		/* Load in the start and ending read addresses */
		LoadStartEndAddresses();

		/* Set the state so that the next UPLOAD requests read out the firmware */
		DFU_State = dfuUPLOAD_IDLE;
	}
	else if (IS_ONEBYTE_COMMAND(SentCommand.Data, 0x01))                       // Blank check FLASH command
	{
		uint32_t CurrFlashAddress = 0;

		while (CurrFlashAddress < BOOT_START_ADDR)
		{
			/* Check if the current byte is not blank */
			#if (FLASHEND > 0xFFFF)
			if (pgm_read_byte_far(CurrFlashAddress) != 0xFF)
			#else
			if (pgm_read_byte(CurrFlashAddress) != 0xFF)
			#endif
			{
				/* Save the location of the first non-blank byte for response back to the host */
				Flash64KBPage = (CurrFlashAddress >> 16);
				StartAddr     = CurrFlashAddress;
656

657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
				/* Set state and status variables to the appropriate error values */
				DFU_State  = dfuERROR;
				DFU_Status = errCHECK_ERASED;

				break;
			}

			CurrFlashAddress++;
		}
	}
}

/** Handler for a Data Write command issued by the host. This routine handles non-programming commands such as
 *  bootloader exit (both via software jumps and hardware watchdog resets) and flash memory erasure.
 */
static void ProcessWriteCommand(void)
{
	if (IS_ONEBYTE_COMMAND(SentCommand.Data, 0x03))                            // Start application
	{
		/* Indicate that the bootloader is terminating */
		WaitForExit = true;

679
680
		/* Check if data supplied for the Start Program command - no data executes the program */
		if (SentCommand.DataSize)
681
		{
682
			if (SentCommand.Data[1] == 0x01)                                   // Start via jump
683
684
685
686
687
688
689
			{
				union
				{
					uint8_t  Bytes[2];
					AppPtr_t FuncPtr;
				} Address = {.Bytes = {SentCommand.Data[4], SentCommand.Data[3]}};

690
				/* Load in the jump address into the application start address pointer */
691
				AppStartPtr = Address.FuncPtr;
692
693
694
695
696
697
698
699
700
701
702
			}
		}
		else
		{
			if (SentCommand.Data[1] == 0x00)                                   // Start via watchdog
			{
				/* Start the watchdog to reset the AVR once the communications are finalized */
				wdt_enable(WDTO_250MS);
			}
			else                                                               // Start via jump
			{
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
				/* Set the flag to terminate the bootloader at next opportunity */
				RunBootloader = false;
			}
		}
	}
	else if (IS_TWOBYTE_COMMAND(SentCommand.Data, 0x00, 0xFF))                 // Erase flash
	{
		uint32_t CurrFlashAddress = 0;

		/* Clear the application section of flash */
		while (CurrFlashAddress < BOOT_START_ADDR)
		{
			boot_page_erase(CurrFlashAddress);
			boot_spm_busy_wait();
			boot_page_write(CurrFlashAddress);
			boot_spm_busy_wait();

			CurrFlashAddress += SPM_PAGESIZE;
		}

		/* Re-enable the RWW section of flash as writing to the flash locks it out */
		boot_rww_enable();
725

726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
		/* Memory has been erased, reset the security bit so that programming/reading is allowed */
		IsSecure = false;
	}
}

/** Handler for a Data Read command issued by the host. This routine handles bootloader information retrieval
 *  commands such as device signature and bootloader version retrieval.
 */
static void ProcessReadCommand(void)
{
	const uint8_t BootloaderInfo[3] = {BOOTLOADER_VERSION, BOOTLOADER_ID_BYTE1, BOOTLOADER_ID_BYTE2};
	const uint8_t SignatureInfo[3]  = {AVR_SIGNATURE_1,    AVR_SIGNATURE_2,     AVR_SIGNATURE_3};

	uint8_t DataIndexToRead = SentCommand.Data[1];

	if (IS_ONEBYTE_COMMAND(SentCommand.Data, 0x00))                         // Read bootloader info
	  ResponseByte = BootloaderInfo[DataIndexToRead];
	else if (IS_ONEBYTE_COMMAND(SentCommand.Data, 0x01))                    // Read signature byte
	  ResponseByte = SignatureInfo[DataIndexToRead - 0x30];
}
746