aboutsummaryrefslogtreecommitdiffstats
path: root/os/hal/ports/STM32/LLD/USARTv2/hal_uart_lld.c
blob: 6c59357c717aea2fe99fdb75c4cca0859d36b394 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
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
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
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
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
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
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
/*
    ChibiOS - Copyright (C) 2006..2016 Giovanni Di Sirio

    Licensed under the Apache License, Version 2.0 (the "License");
    you may not use this file except in compliance with the License.
    You may obtain a copy of the License at

        http://www.apache.org/licenses/LICENSE-2.0

    Unless required by applicable law or agreed to in writing, software
    distributed under the License is distributed on an "AS IS" BASIS,
    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    See the License for the specific language governing permissions and
    limitations under the License.
*/

/**
 * @file    USARTv2/hal_uart_lld.c
 * @brief   STM32 low level UART driver code.
 *
 * @addtogroup UART
 * @{
 */

#include "hal.h"

#if HAL_USE_UART || defined(__DOXYGEN__)

/*===========================================================================*/
/* Driver local definitions.                                                 */
/*===========================================================================*/

/* STM32L0xx/STM32F7xx ST headers difference.*/
#if !defined(USART_ISR_LBDF)
#define USART_ISR_LBDF USART_ISR_LBD
#endif

#define USART1_RX_DMA_CHANNEL                                               \
  STM32_DMA_GETCHANNEL(STM32_UART_USART1_RX_DMA_STREAM,                     \
                       STM32_USART1_RX_DMA_CHN)

#define USART1_TX_DMA_CHANNEL                                               \
  STM32_DMA_GETCHANNEL(STM32_UART_USART1_TX_DMA_STREAM,                     \
                       STM32_USART1_TX_DMA_CHN)

#define USART2_RX_DMA_CHANNEL                                               \
  STM32_DMA_GETCHANNEL(STM32_UART_USART2_RX_DMA_STREAM,                     \
                       STM32_USART2_RX_DMA_CHN)

#define USART2_TX_DMA_CHANNEL                                               \
  STM32_DMA_GETCHANNEL(STM32_UART_USART2_TX_DMA_STREAM,                     \
                       STM32_USART2_TX_DMA_CHN)

#define USART3_RX_DMA_CHANNEL                                               \
  STM32_DMA_GETCHANNEL(STM32_UART_USART3_RX_DMA_STREAM,                     \
                       STM32_USART3_RX_DMA_CHN)

#define USART3_TX_DMA_CHANNEL                                               \
  STM32_DMA_GETCHANNEL(STM32_UART_USART3_TX_DMA_STREAM,                     \
                       STM32_USART3_TX_DMA_CHN)

#define UART4_RX_DMA_CHANNEL                                                \
  STM32_DMA_GETCHANNEL(STM32_UART_UART4_RX_DMA_STREAM,                      \
                       STM32_UART4_RX_DMA_CHN)

#define UART4_TX_DMA_CHANNEL                                                \
  STM32_DMA_GETCHANNEL(STM32_UART_UART4_TX_DMA_STREAM,                      \
                       STM32_UART4_TX_DMA_CHN)

#define UART5_RX_DMA_CHANNEL                                                \
  STM32_DMA_GETCHANNEL(STM32_UART_UART5_RX_DMA_STREAM,                      \
                       STM32_UART5_RX_DMA_CHN)

#define UART5_TX_DMA_CHANNEL                                                \
  STM32_DMA_GETCHANNEL(STM32_UART_UART5_TX_DMA_STREAM,                      \
                       STM32_UART5_TX_DMA_CHN)

#define USART6_RX_DMA_CHANNEL                                               \
  STM32_DMA_GETCHANNEL(STM32_UART_USART6_RX_DMA_STREAM,                     \
                       STM32_USART6_RX_DMA_CHN)

#define USART6_TX_DMA_CHANNEL                                               \
  STM32_DMA_GETCHANNEL(STM32_UART_USART6_TX_DMA_STREAM,                     \
                       STM32_USART6_TX_DMA_CHN)

#define UART7_RX_DMA_CHANNEL                                                \
  STM32_DMA_GETCHANNEL(STM32_UART_UART7_RX_DMA_STREAM,                      \
                       STM32_UART7_RX_DMA_CHN)

#define UART7_TX_DMA_CHANNEL                                                \
  STM32_DMA_GETCHANNEL(STM32_UART_UART7_TX_DMA_STREAM,                      \
                       STM32_UART7_TX_DMA_CHN)

#define UART8_RX_DMA_CHANNEL                                                \
  STM32_DMA_GETCHANNEL(STM32_UART_UART8_RX_DMA_STREAM,                      \
                       STM32_UART8_RX_DMA_CHN)

#define UART8_TX_DMA_CHANNEL                                                \
  STM32_DMA_GETCHANNEL(STM32_UART_UART8_TX_DMA_STREAM,                      \
                       STM32_UART8_TX_DMA_CHN)

/*===========================================================================*/
/* Driver exported variables.                                                */
/*===========================================================================*/

/** @brief USART1 UART driver identifier.*/
#if STM32_UART_USE_USART1 || defined(__DOXYGEN__)
UARTDriver UARTD1;
#endif

/** @brief USART2 UART driver identifier.*/
#if STM32_UART_USE_USART2 || defined(__DOXYGEN__)
UARTDriver UARTD2;
#endif

/** @brief USART3 UART driver identifier.*/
#if STM32_UART_USE_USART3 || defined(__DOXYGEN__)
UARTDriver UARTD3;
#endif

/** @brief UART4 UART driver identifier.*/
#if STM32_UART_USE_UART4 || defined(__DOXYGEN__)
UARTDriver UARTD4;
#endif

/** @brief UART5 UART driver identifier.*/
#if STM32_UART_USE_UART5 || defined(__DOXYGEN__)
UARTDriver UARTD5;
#endif

/** @brief USART6 UART driver identifier.*/
#if STM32_UART_USE_USART6 || defined(__DOXYGEN__)
UARTDriver UARTD6;
#endif

/** @brief UART7 UART driver identifier.*/
#if STM32_UART_USE_UART7 || defined(__DOXYGEN__)
UARTDriver UARTD7;
#endif

/** @brief UART8 UART driver identifier.*/
#if STM32_UART_USE_UART8 || defined(__DOXYGEN__)
UARTDriver UARTD8;
#endif

/*===========================================================================*/
/* Driver local variables and types.                                         */
/*===========================================================================*/

/*===========================================================================*/
/* Driver local functions.                                                   */
/*===========================================================================*/

/**
 * @brief   Status bits translation.
 *
 * @param[in] isr       USART SR register value
 *
 * @return  The error flags.
 */
static uartflags_t translate_errors(uint32_t isr) {
  uartflags_t sts = 0;

  if (isr & USART_ISR_ORE)
    sts |= UART_OVERRUN_ERROR;
  if (isr & USART_ISR_PE)
    sts |= UART_PARITY_ERROR;
  if (isr & USART_ISR_FE)
    sts |= UART_FRAMING_ERROR;
  if (isr & USART_ISR_NE)
    sts |= UART_NOISE_ERROR;
  if (isr & USART_ISR_LBDF)
    sts |= UART_BREAK_DETECTED;
  return sts;
}

/**
 * @brief   Puts the receiver in the UART_RX_IDLE state.
 *
 * @param[in] uartp     pointer to the @p UARTDriver object
 */
static void uart_enter_rx_idle_loop(UARTDriver *uartp) {
  uint32_t mode;
  
  /* RX DMA channel preparation, if the char callback is defined then the
     TCIE interrupt is enabled too.*/
  if (uartp->config->rxchar_cb == NULL)
    mode = STM32_DMA_CR_DIR_P2M | STM32_DMA_CR_CIRC;
  else
    mode = STM32_DMA_CR_DIR_P2M | STM32_DMA_CR_CIRC | STM32_DMA_CR_TCIE;
  dmaStreamSetMemory0(uartp->dmarx, &uartp->rxbuf);
  dmaStreamSetTransactionSize(uartp->dmarx, 1);
  dmaStreamSetMode(uartp->dmarx, uartp->dmamode | mode);
  dmaStreamEnable(uartp->dmarx);
}

/**
 * @brief   USART de-initialization.
 * @details This function must be invoked with interrupts disabled.
 *
 * @param[in] uartp     pointer to the @p UARTDriver object
 */
static void usart_stop(UARTDriver *uartp) {

  /* Stops RX and TX DMA channels.*/
  dmaStreamDisable(uartp->dmarx);
  dmaStreamDisable(uartp->dmatx);
  
  /* Stops USART operations.*/
  uartp->usart->CR1 = 0;
  uartp->usart->CR2 = 0;
  uartp->usart->CR3 = 0;
}

/**
 * @brief   USART initialization.
 * @details This function must be invoked with interrupts disabled.
 *
 * @param[in] uartp     pointer to the @p UARTDriver object
 */
static void usart_start(UARTDriver *uartp) {
  uint32_t cr1;
  const uint32_t tmo = uartp->config->timeout;
  USART_TypeDef *u = uartp->usart;

  /* Defensive programming, starting from a clean state.*/
  usart_stop(uartp);

  /* Baud rate setting.*/
  u->BRR = (uint32_t)(uartp->clock / uartp->config->speed);

  /* Resetting eventual pending status flags.*/
  u->ICR = 0xFFFFFFFFU;

  /* Note that some bits are enforced because required for correct driver
     operations.*/
  u->CR2 = uartp->config->cr2 | USART_CR2_LBDIE;
  u->CR3 = uartp->config->cr3 | USART_CR3_DMAT | USART_CR3_DMAR |
                                USART_CR3_EIE;

  /* Mustn't ever set TCIE here - if done, it causes an immediate
     interrupt.*/
  cr1 = USART_CR1_UE | USART_CR1_PEIE | USART_CR1_TE | USART_CR1_RE;
  u->CR1 = uartp->config->cr1 | cr1;

  /* Set receive timeout and checks if it is really applied.*/
  if (tmo > 0) {
    osalDbgAssert(tmo <= USART_RTOR_RTO, "Timeout overflow");
    u->RTOR = tmo;
    osalDbgAssert(tmo == u->RTOR, "Timeout feature unsupported in this UART");
  }

  /* Starting the receiver idle loop.*/
  uart_enter_rx_idle_loop(uartp);
}

/**
 * @brief   RX DMA common service routine.
 *
 * @param[in] uartp     pointer to the @p UARTDriver object
 * @param[in] flags     pre-shifted content of the ISR register
 */
static void uart_lld_serve_rx_end_irq(UARTDriver *uartp, uint32_t flags) {

  /* DMA errors handling.*/
#if defined(STM32_UART_DMA_ERROR_HOOK)
  if ((flags & (STM32_DMA_ISR_TEIF | STM32_DMA_ISR_DMEIF)) != 0) {
    STM32_UART_DMA_ERROR_HOOK(uartp);
  }
#else
  (void)flags;
#endif

  if (uartp->rxstate == UART_RX_IDLE) {
    /* Receiver in idle state, a callback is generated, if enabled, for each
       received character and then the driver stays in the same state.*/
    _uart_rx_idle_code(uartp);
  }
  else {
    /* Receiver in active state, a callback is generated, if enabled, after
       a completed transfer.*/
    dmaStreamDisable(uartp->dmarx);
    _uart_rx_complete_isr_code(uartp);
  }
}

/**
 * @brief   TX DMA common service routine.
 *
 * @param[in] uartp     pointer to the @p UARTDriver object
 * @param[in] flags     pre-shifted content of the ISR register
 */
static void uart_lld_serve_tx_end_irq(UARTDriver *uartp, uint32_t flags) {

  /* DMA errors handling.*/
#if defined(STM32_UART_DMA_ERROR_HOOK)
  if ((flags & (STM32_DMA_ISR_TEIF | STM32_DMA_ISR_DMEIF)) != 0) {
    STM32_UART_DMA_ERROR_HOOK(uartp);
  }
#else
  (void)flags;
#endif

  dmaStreamDisable(uartp->dmatx);

  /* A callback is generated, if enabled, after a completed transfer.*/
  _uart_tx1_isr_code(uartp);
}

/**
 * @brief   USART common service routine.
 *
 * @param[in] uartp     pointer to the @p UARTDriver object
 */
static void serve_usart_irq(UARTDriver *uartp) {
  uint32_t isr;
  USART_TypeDef *u = uartp->usart;
  uint32_t cr1 = u->CR1;
  
  /* Reading and clearing status.*/
  isr = u->ISR;
  u->ICR = isr;

  if (isr & (USART_ISR_LBDF | USART_ISR_ORE | USART_ISR_NE |
             USART_ISR_FE   | USART_ISR_PE)) {
    _uart_rx_error_isr_code(uartp, translate_errors(isr));
  }

  if ((isr & USART_ISR_TC) && (cr1 & USART_CR1_TCIE)) {
    /* TC interrupt disabled.*/
    u->CR1 = cr1 & ~USART_CR1_TCIE;

    /* End of transmission, a callback is generated.*/
    _uart_tx2_isr_code(uartp);
  }

  /* Timeout interrupt sources are only checked if enabled in CR1.*/
  if (((cr1 & USART_CR1_IDLEIE) && (isr & USART_ISR_IDLE)) ||
      ((cr1 & USART_CR1_RTOIE) && (isr & USART_ISR_RTOF))) {
    _uart_timeout_isr_code(uartp);
  }
}

/*===========================================================================*/
/* Driver interrupt handlers.                                                */
/*===========================================================================*/

#if STM32_UART_USE_USART1 || defined(__DOXYGEN__)
#if !defined(STM32_USART1_HANDLER)
#error "STM32_USART1_HANDLER not defined"
#endif
/**
 * @brief   USART1 IRQ handler.
 *
 * @isr
 */
OSAL_IRQ_HANDLER(STM32_USART1_HANDLER) {

  OSAL_IRQ_PROLOGUE();

  serve_usart_irq(&UARTD1);

  OSAL_IRQ_EPILOGUE();
}
#endif /* STM32_UART_USE_USART1 */

#if STM32_UART_USE_USART2 || defined(__DOXYGEN__)
#if !defined(STM32_USART2_HANDLER)
#error "STM32_USART2_HANDLER not defined"
#endif
/**
 * @brief   USART2 IRQ handler.
 *
 * @isr
 */
OSAL_IRQ_HANDLER(STM32_USART2_HANDLER) {

  OSAL_IRQ_PROLOGUE();

  serve_usart_irq(&UARTD2);

  OSAL_IRQ_EPILOGUE();
}
#endif /* STM32_UART_USE_USART2 */

#if defined(STM32_USART3_8_HANDLER)
#if STM32_UART_USE_USART3 || STM32_UART_USE_UART4  ||                   \
    STM32_UART_USE_UART5  || STM32_UART_USE_USART6 ||                   \
    STM32_UART_USE_UART7  || STM32_UART_USE_UART8  || defined(__DOXYGEN__)
/**
 * @brief   USART3-8 shared interrupt handler.
 *
 * @isr
 */
OSAL_IRQ_HANDLER(STM32_USART3_8_HANDLER) {

  OSAL_IRQ_PROLOGUE();

#if STM32_UART_USE_USART3
  serve_usart_irq(&UARTD3);
#endif
#if STM32_UART_USE_UART4
  serve_usart_irq(&UARTD4);
#endif
#if STM32_UART_USE_UART5
  serve_usart_irq(&UARTD5);
#endif
#if STM32_UART_USE_USART6
  serve_usart_irq(&UARTD6);
#endif
#if STM32_UART_USE_UART7
  serve_usart_irq(&UARTD7);
#endif
#if STM32_UART_USE_UART8
  serve_usart_irq(&UARTD8);
#endif

  OSAL_IRQ_EPILOGUE();
}
#endif

#else /* !defined(STM32_USART3_8_HANDLER) */

#if STM32_UART_USE_USART3 || defined(__DOXYGEN__)
#if !defined(STM32_USART3_HANDLER)
#error "STM32_USART3_HANDLER not defined"
#endif
/**
 * @brief   USART3 IRQ handler.
 *
 * @isr
 */
OSAL_IRQ_HANDLER(STM32_USART3_HANDLER) {

  OSAL_IRQ_PROLOGUE();

  serve_usart_irq(&UARTD3);

  OSAL_IRQ_EPILOGUE();
}
#endif /* STM32_UART_USE_USART3 */

#if STM32_UART_USE_UART4 || defined(__DOXYGEN__)
#if !defined(STM32_UART4_HANDLER)
#error "STM32_UART4_HANDLER not defined"
#endif
/**
 * @brief   UART4 IRQ handler.
 *
 * @isr
 */
OSAL_IRQ_HANDLER(STM32_UART4_HANDLER) {

  OSAL_IRQ_PROLOGUE();

  serve_usart_irq(&UARTD4);

  OSAL_IRQ_EPILOGUE();
}
#endif /* STM32_UART_USE_UART4 */

#if STM32_UART_USE_UART5 || defined(__DOXYGEN__)
#if !defined(STM32_UART5_HANDLER)
#error "STM32_UART5_HANDLER not defined"
#endif
/**
 * @brief   UART5 IRQ handler.
 *
 * @isr
 */
OSAL_IRQ_HANDLER(STM32_UART5_HANDLER) {

  OSAL_IRQ_PROLOGUE();

  serve_usart_irq(&UARTD5);

  OSAL_IRQ_EPILOGUE();
}
#endif /* STM32_UART_USE_UART5 */

#if STM32_UART_USE_USART6 || defined(__DOXYGEN__)
#if !defined(STM32_USART6_HANDLER)
#error "STM32_USART6_HANDLER not defined"
#endif
/**
 * @brief   USART6 IRQ handler.
 *
 * @isr
 */
OSAL_IRQ_HANDLER(STM32_USART6_HANDLER) {

  OSAL_IRQ_PROLOGUE();

  serve_usart_irq(&UARTD6);

  OSAL_IRQ_EPILOGUE();
}
#endif /* STM32_UART_USE_USART6 */

#if STM32_UART_USE_UART7 || defined(__DOXYGEN__)
#if !defined(STM32_UART7_HANDLER)
#error "STM32_UART7_HANDLER not defined"
#endif
/**
 * @brief   UART7 IRQ handler.
 *
 * @isr
 */
OSAL_IRQ_HANDLER(STM32_UART7_HANDLER) {

  OSAL_IRQ_PROLOGUE();

  serve_usart_irq(&UARTD7);

  OSAL_IRQ_EPILOGUE();
}
#endif /* STM32_UART_USE_UART7 */

#if STM32_UART_USE_UART8 || defined(__DOXYGEN__)
#if !defined(STM32_UART8_HANDLER)
#error "STM32_UART8_HANDLER not defined"
#endif
/**
 * @brief   UART8 IRQ handler.
 *
 * @isr
 */
OSAL_IRQ_HANDLER(STM32_UART8_HANDLER) {

  OSAL_IRQ_PROLOGUE();

  serve_usart_irq(&UARTD8);

  OSAL_IRQ_EPILOGUE();
}
#endif /* STM32_UART_USE_UART8 */

#endif /* !defined(STM32_USART3_8_HANDLER) */

/*===========================================================================*/
/* Driver exported functions.                                                */
/*===========================================================================*/

/**
 * @brief   Low level UART driver initialization.
 *
 * @notapi
 */
void uart_lld_init(void) {

#if STM32_UART_USE_USART1
  uartObjectInit(&UARTD1);
  UARTD1.usart   = USART1;
  UARTD1.clock   = STM32_USART1CLK;
  UARTD1.dmamode = STM32_DMA_CR_DMEIE | STM32_DMA_CR_TEIE;
  UARTD1.dmarx   = STM32_DMA_STREAM(STM32_UART_USART1_RX_DMA_STREAM);
  UARTD1.dmatx   = STM32_DMA_STREAM(STM32_UART_USART1_TX_DMA_STREAM);
#if defined(STM32_USART1_NUMBER)
  nvicEnableVector(STM32_USART1_NUMBER, STM32_UART_USART1_IRQ_PRIORITY);
#endif
#endif

#if STM32_UART_USE_USART2
  uartObjectInit(&UARTD2);
  UARTD2.usart   = USART2;
  UARTD2.clock   = STM32_USART2CLK;
  UARTD2.dmamode = STM32_DMA_CR_DMEIE | STM32_DMA_CR_TEIE;
  UARTD2.dmarx   = STM32_DMA_STREAM(STM32_UART_USART2_RX_DMA_STREAM);
  UARTD2.dmatx   = STM32_DMA_STREAM(STM32_UART_USART2_TX_DMA_STREAM);
#if defined(STM32_USART2_NUMBER)
  nvicEnableVector(STM32_USART2_NUMBER, STM32_UART_USART2_IRQ_PRIORITY);
#endif
#endif

#if STM32_UART_USE_USART3
  uartObjectInit(&UARTD3);
  UARTD3.usart   = USART3;
  UARTD3.clock   = STM32_USART3CLK;
  UARTD3.dmamode = STM32_DMA_CR_DMEIE | STM32_DMA_CR_TEIE;
  UARTD3.dmarx   = STM32_DMA_STREAM(STM32_UART_USART3_RX_DMA_STREAM);
  UARTD3.dmatx   = STM32_DMA_STREAM(STM32_UART_USART3_TX_DMA_STREAM);
#if defined(STM32_USART3_NUMBER)
  nvicEnableVector(STM32_USART3_NUMBER, STM32_UART_USART3_IRQ_PRIORITY);
#endif
#endif

#if STM32_UART_USE_UART4
  uartObjectInit(&UARTD4);
  UARTD4.usart   = UART4;
  UARTD4.clock   = STM32_UART4CLK;
  UARTD4.dmamode = STM32_DMA_CR_DMEIE | STM32_DMA_CR_TEIE;
  UARTD4.dmarx   = STM32_DMA_STREAM(STM32_UART_UART4_RX_DMA_STREAM);
  UARTD4.dmatx   = STM32_DMA_STREAM(STM32_UART_UART4_TX_DMA_STREAM);
#if defined(STM32_UART4_NUMBER)
  nvicEnableVector(STM32_UART4_NUMBER, STM32_UART_UART4_IRQ_PRIORITY);
#endif
#endif

#if STM32_UART_USE_UART5
  uartObjectInit(&UARTD5);
  UARTD5.usart   = UART5;
  UARTD5.clock   = STM32_UART5CLK;
  UARTD5.dmamode = STM32_DMA_CR_DMEIE | STM32_DMA_CR_TEIE;
  UARTD5.dmarx   = STM32_DMA_STREAM(STM32_UART_UART5_RX_DMA_STREAM);
  UARTD5.dmatx   = STM32_DMA_STREAM(STM32_UART_UART5_TX_DMA_STREAM);
#if defined(STM32_UART5_NUMBER)
  nvicEnableVector(STM32_UART5_NUMBER, STM32_UART_UART5_IRQ_PRIORITY);
#endif
#endif

#if STM32_UART_USE_USART6
  uartObjectInit(&UARTD6);
  UARTD6.usart   = USART6;
  UARTD6.clock   = STM32_USART6CLK;
  UARTD6.dmamode = STM32_DMA_CR_DMEIE | STM32_DMA_CR_TEIE;
  UARTD6.dmarx   = STM32_DMA_STREAM(STM32_UART_USART6_RX_DMA_STREAM);
  UARTD6.dmatx   = STM32_DMA_STREAM(STM32_UART_USART6_TX_DMA_STREAM);
#if defined(STM32_USART6_NUMBER)
  nvicEnableVector(STM32_USART6_NUMBER, STM32_UART_USART6_IRQ_PRIORITY);
#endif
#endif

#if STM32_UART_USE_UART7
  uartObjectInit(&UARTD7);
  UARTD7.usart   = UART7;
  UARTD7.clock   = STM32_UART7CLK;
  UARTD7.dmamode = STM32_DMA_CR_DMEIE | STM32_DMA_CR_TEIE;
  UARTD7.dmarx   = STM32_DMA_STREAM(STM32_UART_UART7_RX_DMA_STREAM);
  UARTD7.dmatx   = STM32_DMA_STREAM(STM32_UART_UART7_TX_DMA_STREAM);
#if defined(STM32_UART7_NUMBER)
  nvicEnableVector(STM32_UART7_NUMBER, STM32_UART_UART7_IRQ_PRIORITY);
#endif
#endif

#if STM32_UART_USE_UART8
  uartObjectInit(&UARTD8);
  UARTD8.usart   = UART8;
  UARTD8.clock   = STM32_UART8CLK;
  UARTD8.dmamode = STM32_DMA_CR_DMEIE | STM32_DMA_CR_TEIE;
  UARTD8.dmarx   = STM32_DMA_STREAM(STM32_UART_UART8_RX_DMA_STREAM);
  UARTD8.dmatx   = STM32_DMA_STREAM(STM32_UART_UART8_TX_DMA_STREAM);
#if defined(STM32_UART8_NUMBER)
  nvicEnableVector(STM32_UART8_NUMBER, STM32_UART_UART8_IRQ_PRIORITY);
#endif
#endif

#if STM32_UART_USE_USART3 || STM32_UART_USE_UART4  ||                   \
    STM32_UART_USE_UART5  || STM32_UART_USE_USART6 ||                   \
    STM32_UART_USE_UART7  || STM32_UART_USE_UART8
#if defined(STM32_USART3_8_HANDLER)
  nvicEnableVector(STM32_USART3_8_NUMBER, STM32_UART_USART3_8_PRIORITY);
#endif
#endif
}

/**
 * @brief   Configures and activates the UART peripheral.
 *
 * @param[in] uartp     pointer to the @p UARTDriver object
 *
 * @notapi
 */
void uart_lld_start(UARTDriver *uartp) {

  if (uartp->state == UART_STOP) {
#if STM32_UART_USE_USART1
    if (&UARTD1 == uartp) {
      bool b;
      b = dmaStreamAllocate(uartp->dmarx,
                            STM32_UART_USART1_IRQ_PRIORITY,
                            (stm32_dmaisr_t)uart_lld_serve_rx_end_irq,
                            (void *)uartp);
      osalDbgAssert(!b, "stream already allocated");
      b = dmaStreamAllocate(uartp->dmatx,
                            STM32_UART_USART1_IRQ_PRIORITY,
                            (stm32_dmaisr_t)uart_lld_serve_tx_end_irq,
                            (void *)uartp);
      osalDbgAssert(!b, "stream already allocated");
      rccEnableUSART1(FALSE);
      uartp->dmamode |= STM32_DMA_CR_CHSEL(USART1_RX_DMA_CHANNEL) |
                        STM32_DMA_CR_PL(STM32_UART_USART1_DMA_PRIORITY);
    }
#endif

#if STM32_UART_USE_USART2
    if (&UARTD2 == uartp) {
      bool b;
      b = dmaStreamAllocate(uartp->dmarx,
                            STM32_UART_USART2_IRQ_PRIORITY,
                            (stm32_dmaisr_t)uart_lld_serve_rx_end_irq,
                            (void *)uartp);
      osalDbgAssert(!b, "stream already allocated");
      b = dmaStreamAllocate(uartp->dmatx,
                            STM32_UART_USART2_IRQ_PRIORITY,
                            (stm32_dmaisr_t)uart_lld_serve_tx_end_irq,
                            (void *)uartp);
      osalDbgAssert(!b, "stream already allocated");
      rccEnableUSART2(FALSE);
      uartp->dmamode |= STM32_DMA_CR_CHSEL(USART2_RX_DMA_CHANNEL) |
                        STM32_DMA_CR_PL(STM32_UART_USART2_DMA_PRIORITY);
    }
#endif

#if STM32_UART_USE_USART3
    if (&UARTD3 == uartp) {
      bool b;
      b = dmaStreamAllocate(uartp->dmarx,
                            STM32_UART_USART3_IRQ_PRIORITY,
                            (stm32_dmaisr_t)uart_lld_serve_rx_end_irq,
                            (void *)uartp);
      osalDbgAssert(!b, "stream already allocated");
      b = dmaStreamAllocate(uartp->dmatx,
                            STM32_UART_USART3_IRQ_PRIORITY,
                            (stm32_dmaisr_t)uart_lld_serve_tx_end_irq,
                            (void *)uartp);
      osalDbgAssert(!b, "stream already allocated");
      rccEnableUSART3(FALSE);
      uartp->dmamode |= STM32_DMA_CR_CHSEL(USART3_RX_DMA_CHANNEL) |
                        STM32_DMA_CR_PL(STM32_UART_USART3_DMA_PRIORITY);
    }
#endif

#if STM32_UART_USE_UART4
    if (&UARTD4 == uartp) {
      bool b;
      b = dmaStreamAllocate(uartp->dmarx,
                            STM32_UART_UART4_IRQ_PRIORITY,
                            (stm32_dmaisr_t)uart_lld_serve_rx_end_irq,
                            (void *)uartp);
      osalDbgAssert(!b, "stream already allocated");
      b = dmaStreamAllocate(uartp->dmatx,
                            STM32_UART_UART4_IRQ_PRIORITY,
                            (stm32_dmaisr_t)uart_lld_serve_tx_end_irq,
                            (void *)uartp);
      osalDbgAssert(!b, "stream already allocated");
      rccEnableUART4(FALSE);
      uartp->dmamode |= STM32_DMA_CR_CHSEL(UART4_RX_DMA_CHANNEL) |
                        STM32_DMA_CR_PL(STM32_UART_UART4_DMA_PRIORITY);
    }
#endif

#if STM32_UART_USE_UART5
    if (&UARTD5 == uartp) {
      bool b;
      b = dmaStreamAllocate(uartp->dmarx,
                            STM32_UART_UART5_IRQ_PRIORITY,
                            (stm32_dmaisr_t)uart_lld_serve_rx_end_irq,
                            (void *)uartp);
      osalDbgAssert(!b, "stream already allocated");
      b = dmaStreamAllocate(uartp->dmatx,
                            STM32_UART_UART5_IRQ_PRIORITY,
                            (stm32_dmaisr_t)uart_lld_serve_tx_end_irq,
                            (void *)uartp);
      osalDbgAssert(!b, "stream already allocated");
      rccEnableUART5(FALSE);
      uartp->dmamode |= STM32_DMA_CR_CHSEL(UART5_RX_DMA_CHANNEL) |
                        STM32_DMA_CR_PL(STM32_UART_UART5_DMA_PRIORITY);
    }
#endif

#if STM32_UART_USE_USART6
    if (&UARTD6 == uartp) {
      bool b;
      b = dmaStreamAllocate(uartp->dmarx,
                            STM32_UART_USART6_IRQ_PRIORITY,
                            (stm32_dmaisr_t)uart_lld_serve_rx_end_irq,
                            (void *)uartp);
      osalDbgAssert(!b, "stream already allocated");
      b = dmaStreamAllocate(uartp->dmatx,
                            STM32_UART_USART6_IRQ_PRIORITY,
                            (stm32_dmaisr_t)uart_lld_serve_tx_end_irq,
                            (void *)uartp);
      osalDbgAssert(!b, "stream already allocated");
      rccEnableUSART6(FALSE);
      uartp->dmamode |= STM32_DMA_CR_CHSEL(USART6_RX_DMA_CHANNEL) |
                        STM32_DMA_CR_PL(STM32_UART_USART6_DMA_PRIORITY);
    }
#endif

#if STM32_UART_USE_UART7
    if (&UARTD7 == uartp) {
      bool b;
      b = dmaStreamAllocate(uartp->dmarx,
                            STM32_UART_UART7_IRQ_PRIORITY,
                            (stm32_dmaisr_t)uart_lld_serve_rx_end_irq,
                            (void *)uartp);
      osalDbgAssert(!b, "stream already allocated");
      b = dmaStreamAllocate(uartp->dmatx,
                            STM32_UART_UART7_IRQ_PRIORITY,
                            (stm32_dmaisr_t)uart_lld_serve_tx_end_irq,
                            (void *)uartp);
      osalDbgAssert(!b, "stream already allocated");
      rccEnableUART7(FALSE);
      uartp->dmamode |= STM32_DMA_CR_CHSEL(UART7_RX_DMA_CHANNEL) |
                        STM32_DMA_CR_PL(STM32_UART_UART7_DMA_PRIORITY);
    }
#endif

#if STM32_UART_USE_UART8
    if (&UARTD8 == uartp) {
      bool b;
      b = dmaStreamAllocate(uartp->dmarx,
                            STM32_UART_UART8_IRQ_PRIORITY,
                            (stm32_dmaisr_t)uart_lld_serve_rx_end_irq,
                            (void *)uartp);
      osalDbgAssert(!b, "stream already allocated");
      b = dmaStreamAllocate(uartp->dmatx,
                            STM32_UART_UART8_IRQ_PRIORITY,
                            (stm32_dmaisr_t)uart_lld_serve_tx_end_irq,
                            (void *)uartp);
      osalDbgAssert(!b, "stream already allocated");
      rccEnableUART8(FALSE);
      uartp->dmamode |= STM32_DMA_CR_CHSEL(UART8_RX_DMA_CHANNEL) |
                        STM32_DMA_CR_PL(STM32_UART_UART8_DMA_PRIORITY);
    }
#endif

    /* Static DMA setup, the transfer size depends on the USART settings,
       it is 16 bits if M=1 and PCE=0 else it is 8 bits.*/
    if ((uartp->config->cr1 & (USART_CR1_M | USART_CR1_PCE)) == USART_CR1_M)
      uartp->dmamode |= STM32_DMA_CR_PSIZE_HWORD | STM32_DMA_CR_MSIZE_HWORD;
    dmaStreamSetPeripheral(uartp->dmarx, &uartp->usart->RDR);
    dmaStreamSetPeripheral(uartp->dmatx, &uartp->usart->TDR);
    uartp->rxbuf = 0;
  }

  uartp->rxstate = UART_RX_IDLE;
  uartp->txstate = UART_TX_IDLE;
  usart_start(uartp);
}

/**
 * @brief   Deactivates the UART peripheral.
 *
 * @param[in] uartp     pointer to the @p UARTDriver object
 *
 * @notapi
 */
void uart_lld_stop(UARTDriver *uartp) {

  if (uartp->state == UART_READY) {
    usart_stop(uartp);
    dmaStreamRelease(uartp->dmarx);
    dmaStreamRelease(uartp->dmatx);

#if STM32_UART_USE_USART1
    if (&UARTD1 == uartp) {
      rccDisableUSART1(FALSE);
      return;
    }
#endif

#if STM32_UART_USE_USART2
    if (&UARTD2 == uartp) {
      rccDisableUSART2(FALSE);
      return;
    }
#endif

#if STM32_UART_USE_USART3
    if (&UARTD3 == uartp) {
      rccDisableUSART3(FALSE);
      return;
    }
#endif

#if STM32_UART_USE_UART4
    if (&UARTD4 == uartp) {
      rccDisableUART4(FALSE);
      return;
    }
#endif

#if STM32_UART_USE_UART5
    if (&UARTD5 == uartp) {
      rccDisableUART5(FALSE);
      return;
    }
#endif

#if STM32_UART_USE_USART6
    if (&UARTD6 == uartp) {
      rccDisableUSART6(FALSE);
      return;
    }
#endif

#if STM32_UART_USE_UART7
    if (&UARTD7 == uartp) {
      rccDisableUART7(FALSE);
      return;
    }
#endif

#if STM32_UART_USE_UART8
    if (&UARTD8 == uartp) {
      rccDisableUART8(FALSE);
      return;
    }
#endif
  }
}

/**
 * @brief   Starts a transmission on the UART peripheral.
 * @note    The buffers are organized as uint8_t arrays for data sizes below
 *          or equal to 8 bits else it is organized as uint16_t arrays.
 *
 * @param[in] uartp     pointer to the @p UARTDriver object
 * @param[in] n         number of data frames to send
 * @param[in] txbuf     the pointer to the transmit buffer
 *
 * @notapi
 */
void uart_lld_start_send(UARTDriver *uartp, size_t n, const void *txbuf) {

  /* TX DMA channel preparation.*/
  dmaStreamSetMemory0(uartp->dmatx, txbuf);
  dmaStreamSetTransactionSize(uartp->dmatx, n);
  dmaStreamSetMode(uartp->dmatx, uartp->dmamode    | STM32_DMA_CR_DIR_M2P |
                                 STM32_DMA_CR_MINC | STM32_DMA_CR_TCIE);

  /* Only enable TC interrupt if there's a callback attached to it.
     Also we need to clear TC flag which could be set before. */
  if (uartp->config->txend2_cb != NULL) {
    uartp->usart->ICR = USART_ICR_TCCF;
    uartp->usart->CR1 |= USART_CR1_TCIE;
  }

  /* Starting transfer.*/
  dmaStreamEnable(uartp->dmatx);
}

/**
 * @brief   Stops any ongoing transmission.
 * @note    Stopping a transmission also suppresses the transmission callbacks.
 *
 * @param[in] uartp     pointer to the @p UARTDriver object
 *
 * @return              The number of data frames not transmitted by the
 *                      stopped transmit operation.
 *
 * @notapi
 */
size_t uart_lld_stop_send(UARTDriver *uartp) {

  dmaStreamDisable(uartp->dmatx);

  return dmaStreamGetTransactionSize(uartp->dmatx);
}

/**
 * @brief   Starts a receive operation on the UART peripheral.
 * @note    The buffers are organized as uint8_t arrays for data sizes below
 *          or equal to 8 bits else it is organized as uint16_t arrays.
 *
 * @param[in] uartp     pointer to the @p UARTDriver object
 * @param[in] n         number of data frames to send
 * @param[out] rxbuf    the pointer to the receive buffer
 *
 * @notapi
 */
void uart_lld_start_receive(UARTDriver *uartp, size_t n, void *rxbuf) {

  /* Stopping previous activity (idle state).*/
  dmaStreamDisable(uartp->dmarx);

  /* RX DMA channel preparation.*/
  dmaStreamSetMemory0(uartp->dmarx, rxbuf);
  dmaStreamSetTransactionSize(uartp->dmarx, n);
  dmaStreamSetMode(uartp->dmarx, uartp->dmamode    | STM32_DMA_CR_DIR_P2M |
                                 STM32_DMA_CR_MINC | STM32_DMA_CR_TCIE);

  /* Starting transfer.*/
  dmaStreamEnable(uartp->dmarx);
}

/**
 * @brief   Stops any ongoing receive operation.
 * @note    Stopping a receive operation also suppresses the receive callbacks.
 *
 * @param[in] uartp     pointer to the @p UARTDriver object
 *
 * @return              The number of data frames not received by the
 *                      stopped receive operation.
 *
 * @notapi
 */
size_t uart_lld_stop_receive(UARTDriver *uartp) {
  size_t n;

  dmaStreamDisable(uartp->dmarx);
  n = dmaStreamGetTransactionSize(uartp->dmarx);
  uart_enter_rx_idle_loop(uartp);

  return n;
}

#endif /* HAL_USE_UART */

/** @} */