Boot Linux faster!

Check our new training course

Boot Linux faster!

Check our new training course
and Creative Commons CC-BY-SA
lecture and lab materials

Bootlin logo

Elixir Cross Referencer

   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
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
/*
 * Copyright (c) 2016-2019 Nordic Semiconductor ASA
 *
 * SPDX-License-Identifier: Apache-2.0
 */

/**
 * @brief Driver for Nordic Semiconductor nRF5X UART
 */

#include <drivers/uart.h>
#include <hal/nrf_uart.h>
#include <hal/nrf_gpio.h>


static NRF_UART_Type *const uart0_addr =
		(NRF_UART_Type *)DT_NORDIC_NRF_UART_UART_0_BASE_ADDRESS;

/* Device data structure */
struct uart_nrfx_data {
	struct uart_config uart_config;
};

/**
 * @brief Structure for UART configuration.
 */
struct uart_nrfx_config {
	bool rts_cts_pins_set;
};

static inline struct uart_nrfx_data *get_dev_data(struct device *dev)
{
	return dev->driver_data;
}

static inline const struct uart_nrfx_config *get_dev_config(struct device *dev)
{
	return dev->config->config_info;
}

#ifdef CONFIG_UART_0_ASYNC
static struct {
	uart_callback_t callback;
	void *user_data;

	u8_t *rx_buffer;
	u8_t *rx_secondary_buffer;
	size_t rx_buffer_length;
	size_t rx_secondary_buffer_length;
	volatile size_t rx_counter;
	volatile size_t rx_offset;
	size_t rx_timeout;
	struct k_delayed_work rx_timeout_work;
	bool rx_enabled;

	bool tx_abort;
	const u8_t *tx_buffer;
	size_t tx_buffer_length;
	volatile size_t tx_counter;
#if defined(DT_NORDIC_NRF_UART_UART_0_RTS_PIN) && \
		defined(DT_NORDIC_NRF_UART_UART_0_CTS_PIN)
	size_t tx_timeout;
	struct k_delayed_work tx_timeout_work;
#endif
} uart0_cb;
#endif /* CONFIG_UART_0_ASYNC */

#ifdef CONFIG_UART_0_INTERRUPT_DRIVEN

static uart_irq_callback_user_data_t irq_callback; /**< Callback function pointer */
static void *irq_cb_data; /**< Callback function arg */

/* Variable used to override the state of the TXDRDY event in the initial state
 * of the driver. This event is not set by the hardware until a first byte is
 * sent, and we want to use it as an indication if the transmitter is ready
 * to accept a new byte.
 */
static volatile u8_t uart_sw_event_txdrdy;

#endif /* CONFIG_UART_0_INTERRUPT_DRIVEN */


static bool event_txdrdy_check(void)
{
	return (nrf_uart_event_check(uart0_addr, NRF_UART_EVENT_TXDRDY)
#ifdef CONFIG_UART_0_INTERRUPT_DRIVEN
		|| uart_sw_event_txdrdy
#endif
	       );
}

static void event_txdrdy_clear(void)
{
	nrf_uart_event_clear(uart0_addr, NRF_UART_EVENT_TXDRDY);
#ifdef CONFIG_UART_0_INTERRUPT_DRIVEN
	uart_sw_event_txdrdy = 0U;
#endif
}


/**
 * @brief Set the baud rate
 *
 * This routine set the given baud rate for the UART.
 *
 * @param dev UART device struct
 * @param baudrate Baud rate
 *
 * @return N/A
 */

static int baudrate_set(struct device *dev, u32_t baudrate)
{
	nrf_uart_baudrate_t nrf_baudrate; /* calculated baudrate divisor */

	switch (baudrate) {
	case 300:
		/* value not supported by Nordic HAL */
		nrf_baudrate = 0x00014000;
		break;
	case 600:
		/* value not supported by Nordic HAL */
		nrf_baudrate = 0x00027000;
		break;
	case 1200:
		nrf_baudrate = NRF_UART_BAUDRATE_1200;
		break;
	case 2400:
		nrf_baudrate = NRF_UART_BAUDRATE_2400;
		break;
	case 4800:
		nrf_baudrate = NRF_UART_BAUDRATE_4800;
		break;
	case 9600:
		nrf_baudrate = NRF_UART_BAUDRATE_9600;
		break;
	case 14400:
		nrf_baudrate = NRF_UART_BAUDRATE_14400;
		break;
	case 19200:
		nrf_baudrate = NRF_UART_BAUDRATE_19200;
		break;
	case 28800:
		nrf_baudrate = NRF_UART_BAUDRATE_28800;
		break;
	case 31250:
		nrf_baudrate = NRF_UART_BAUDRATE_31250;
		break;
	case 38400:
		nrf_baudrate = NRF_UART_BAUDRATE_38400;
		break;
	case 56000:
		nrf_baudrate = NRF_UART_BAUDRATE_56000;
		break;
	case 57600:
		nrf_baudrate = NRF_UART_BAUDRATE_57600;
		break;
	case 76800:
		nrf_baudrate = NRF_UART_BAUDRATE_76800;
		break;
	case 115200:
		nrf_baudrate = NRF_UART_BAUDRATE_115200;
		break;
	case 230400:
		nrf_baudrate = NRF_UART_BAUDRATE_230400;
		break;
	case 250000:
		nrf_baudrate = NRF_UART_BAUDRATE_250000;
		break;
	case 460800:
		nrf_baudrate = NRF_UART_BAUDRATE_460800;
		break;
	case 921600:
		nrf_baudrate = NRF_UART_BAUDRATE_921600;
		break;
	case 1000000:
		nrf_baudrate = NRF_UART_BAUDRATE_1000000;
		break;
	default:
		return -EINVAL;
	}

	nrf_uart_baudrate_set(uart0_addr, nrf_baudrate);

	return 0;
}

/**
 * @brief Poll the device for input.
 *
 * @param dev UART device struct
 * @param c Pointer to character
 *
 * @return 0 if a character arrived, -1 if the input buffer if empty.
 */

static int uart_nrfx_poll_in(struct device *dev, unsigned char *c)
{
	if (!nrf_uart_event_check(uart0_addr, NRF_UART_EVENT_RXDRDY)) {
		return -1;
	}

	/* Clear the interrupt */
	nrf_uart_event_clear(uart0_addr, NRF_UART_EVENT_RXDRDY);

	/* got a character */
	*c = nrf_uart_rxd_get(uart0_addr);

	return 0;
}

/**
 * @brief Output a character in polled mode.
 *
 * @param dev UART device struct
 * @param c Character to send
 */
static void uart_nrfx_poll_out(struct device *dev,
					unsigned char c)
{
	/* The UART API dictates that poll_out should wait for the transmitter
	 * to be empty before sending a character. However, without locking,
	 * this introduces a rare yet possible race condition if the thread is
	 * preempted between sending the byte and checking for completion.

	 * Because of this race condition, the while loop has to be placed
	 * after the write to TXD, and we can't wait for an empty transmitter
	 * before writing. This is a trade-off between losing a byte once in a
	 * blue moon against hanging up the whole thread permanently
	 */

	/* Reset the transmitter ready state. */
	event_txdrdy_clear();

	/* Activate the transmitter. */
	nrf_uart_task_trigger(uart0_addr, NRF_UART_TASK_STARTTX);

	/* Send the provided character. */
	nrf_uart_txd_set(uart0_addr, (u8_t)c);

	/* Wait until the transmitter is ready, i.e. the character is sent. */
	while (!event_txdrdy_check()) {
	}

	/* Deactivate the transmitter so that it does not needlessly consume
	 * power.
	 */
	nrf_uart_task_trigger(uart0_addr, NRF_UART_TASK_STOPTX);
}

/** Console I/O function */
static int uart_nrfx_err_check(struct device *dev)
{
	u32_t error = 0U;

	if (nrf_uart_event_check(uart0_addr, NRF_UART_EVENT_ERROR)) {
		/* register bitfields maps to the defines in uart.h */
		error = nrf_uart_errorsrc_get_and_clear(uart0_addr);
	}

	return error;
}

static int uart_nrfx_configure(struct device *dev,
			       const struct uart_config *cfg)
{
	nrf_uart_parity_t parity;
	nrf_uart_hwfc_t hwfc;

	if (cfg->stop_bits != UART_CFG_STOP_BITS_1) {
		return -ENOTSUP;
	}

	if (cfg->data_bits != UART_CFG_DATA_BITS_8) {
		return -ENOTSUP;
	}

	switch (cfg->flow_ctrl) {
	case UART_CFG_FLOW_CTRL_NONE:
		hwfc = NRF_UART_HWFC_DISABLED;
		break;
	case UART_CFG_FLOW_CTRL_RTS_CTS:
		if (get_dev_config(dev)->rts_cts_pins_set) {
			hwfc = NRF_UART_HWFC_ENABLED;
		} else {
			return -ENOTSUP;
		}
		break;
	default:
		return -ENOTSUP;
	}

	switch (cfg->parity) {
	case UART_CFG_PARITY_NONE:
		parity = NRF_UART_PARITY_EXCLUDED;
		break;
	case UART_CFG_PARITY_EVEN:
		parity = NRF_UART_PARITY_INCLUDED;
		break;
	default:
		return -ENOTSUP;
	}

	if (baudrate_set(dev, cfg->baudrate) != 0) {
		return -ENOTSUP;
	}

	nrf_uart_configure(uart0_addr, parity, hwfc);

	get_dev_data(dev)->uart_config = *cfg;

	return 0;
}

static int uart_nrfx_config_get(struct device *dev, struct uart_config *cfg)
{
	*cfg = get_dev_data(dev)->uart_config;
	return 0;
}


#ifdef CONFIG_UART_0_ASYNC

static void user_callback(struct uart_event *event)
{
	if (uart0_cb.callback) {
		uart0_cb.callback(event, uart0_cb.user_data);
	}
}

static int uart_nrfx_callback_set(struct device *dev, uart_callback_t callback,
				  void *user_data)
{
	uart0_cb.callback = callback;
	uart0_cb.user_data = user_data;

	return 0;
}

static int uart_nrfx_tx(struct device *dev, const u8_t *buf, size_t len,
			u32_t timeout)
{
	if (uart0_cb.tx_buffer_length != 0) {
		return -EBUSY;
	}

	uart0_cb.tx_buffer = buf;
	uart0_cb.tx_buffer_length = len;
#if	defined(DT_NORDIC_NRF_UART_UART_0_RTS_PIN) && \
	defined(DT_NORDIC_NRF_UART_UART_0_CTS_PIN)
	uart0_cb.tx_timeout = timeout;
#endif
	nrf_uart_event_clear(uart0_addr, NRF_UART_EVENT_TXDRDY);
	nrf_uart_task_trigger(uart0_addr, NRF_UART_TASK_STARTTX);
	nrf_uart_event_clear(uart0_addr, NRF_UART_EVENT_TXDRDY);
	nrf_uart_int_enable(uart0_addr, NRF_UART_INT_MASK_TXDRDY);

	u8_t txd = uart0_cb.tx_buffer[uart0_cb.tx_counter];

	nrf_uart_txd_set(uart0_addr, txd);

	return 0;
}

static int uart_nrfx_tx_abort(struct device *dev)
{
	if (uart0_cb.tx_buffer_length == 0) {
		return -EINVAL;
	}
#if	defined(DT_NORDIC_NRF_UART_UART_0_RTS_PIN) && \
	defined(DT_NORDIC_NRF_UART_UART_0_CTS_PIN)
	k_delayed_work_cancel(&uart0_cb.tx_timeout_work);
#endif
	nrf_uart_task_trigger(uart0_addr, NRF_UART_TASK_STOPTX);

	struct uart_event evt = {
		.type = UART_TX_ABORTED,
		.data.tx.buf = uart0_cb.tx_buffer,
		.data.tx.len = uart0_cb.tx_counter
	};

	uart0_cb.tx_buffer_length = 0;
	uart0_cb.tx_counter = 0;

	user_callback(&evt);

	return 0;
}

static int uart_nrfx_rx_enable(struct device *dev, u8_t *buf, size_t len,
			       u32_t timeout)
{
	if (uart0_cb.rx_buffer_length != 0) {
		return -EBUSY;
	}
	uart0_cb.rx_enabled = 1;
	uart0_cb.rx_buffer = buf;
	uart0_cb.rx_buffer_length = len;
	uart0_cb.rx_counter = 0;
	uart0_cb.rx_secondary_buffer_length = 0;
	uart0_cb.rx_timeout = timeout;

	nrf_uart_event_clear(uart0_addr, NRF_UART_EVENT_ERROR);
	nrf_uart_event_clear(uart0_addr, NRF_UART_EVENT_RXDRDY);
	nrf_uart_event_clear(uart0_addr, NRF_UART_EVENT_RXTO);
	nrf_uart_task_trigger(uart0_addr, NRF_UART_TASK_STARTRX);
	nrf_uart_int_enable(uart0_addr, NRF_UART_INT_MASK_RXDRDY |
					NRF_UART_INT_MASK_ERROR |
					NRF_UART_INT_MASK_RXTO);

	return 0;
}

static int uart_nrfx_rx_buf_rsp(struct device *dev, u8_t *buf, size_t len)
{
	if (!uart0_cb.rx_enabled) {
		return -EACCES;
	}
	if (uart0_cb.rx_secondary_buffer_length != 0) {
		return -EBUSY;
	}
	uart0_cb.rx_secondary_buffer = buf;
	uart0_cb.rx_secondary_buffer_length = len;

	return 0;
}

static int uart_nrfx_rx_disable(struct device *dev)
{
	if (uart0_cb.rx_buffer_length == 0) {
		return -EFAULT;
	}

	uart0_cb.rx_enabled = 0;
	k_delayed_work_cancel(&uart0_cb.rx_timeout_work);
	nrf_uart_task_trigger(uart0_addr, NRF_UART_TASK_STOPRX);

	return 0;
}

static void rx_rdy_evt(void)
{
	struct uart_event event;
	size_t rx_cnt = uart0_cb.rx_counter;

	event.type = UART_RX_RDY;
	event.data.rx.buf = uart0_cb.rx_buffer;
	event.data.rx.len = rx_cnt - uart0_cb.rx_offset;
	event.data.rx.offset = uart0_cb.rx_offset;

	uart0_cb.rx_offset = rx_cnt;

	user_callback(&event);
}

static void buf_released_evt(void)
{
	struct uart_event event = {
		.type = UART_RX_BUF_RELEASED,
		.data.rx_buf.buf = uart0_cb.rx_buffer
	};
	user_callback(&event);
}

static void rx_disabled_evt(void)
{
	struct uart_event event = {
		.type = UART_RX_DISABLED
	};
	user_callback(&event);
}

static void rx_reset_state(void)
{
	nrf_uart_int_disable(uart0_addr,
			     NRF_UART_INT_MASK_RXDRDY |
			     NRF_UART_INT_MASK_ERROR |
			     NRF_UART_INT_MASK_RXTO);
	uart0_cb.rx_buffer_length = 0;
	uart0_cb.rx_enabled = 0;
	uart0_cb.rx_counter = 0;
	uart0_cb.rx_offset = 0;
	uart0_cb.rx_secondary_buffer_length = 0;
}

static void rx_isr(struct device *dev)
{
	struct uart_event event;

	nrf_uart_event_clear(uart0_addr, NRF_UART_EVENT_RXDRDY);

	if (!uart0_cb.rx_buffer_length || !uart0_cb.rx_enabled) {
		/* Byte received when receiving is disabled - data lost. */
		nrf_uart_rxd_get(uart0_addr);
	} else {
		if (uart0_cb.rx_counter == 0) {
			event.type = UART_RX_BUF_REQUEST;
			user_callback(&event);
		}
		uart0_cb.rx_buffer[uart0_cb.rx_counter] =
			nrf_uart_rxd_get(uart0_addr);
		uart0_cb.rx_counter++;
		if (uart0_cb.rx_timeout == K_NO_WAIT) {
			rx_rdy_evt();
		} else if (uart0_cb.rx_timeout != K_FOREVER) {
			k_delayed_work_submit(&uart0_cb.rx_timeout_work,
					      uart0_cb.rx_timeout);
		}
	}

	if (uart0_cb.rx_buffer_length == uart0_cb.rx_counter) {
		k_delayed_work_cancel(&uart0_cb.rx_timeout_work);
		rx_rdy_evt();

		if (uart0_cb.rx_secondary_buffer_length) {
			buf_released_evt();
			/* Switch to secondary buffer. */
			uart0_cb.rx_buffer_length =
				uart0_cb.rx_secondary_buffer_length;
			uart0_cb.rx_buffer = uart0_cb.rx_secondary_buffer;
			uart0_cb.rx_secondary_buffer_length = 0;
			uart0_cb.rx_counter = 0;
			uart0_cb.rx_offset = 0;

			event.type = UART_RX_BUF_REQUEST;
			user_callback(&event);
		} else {
			uart_nrfx_rx_disable(dev);
		}
	}
}

static void tx_isr(void)
{
	uart0_cb.tx_counter++;
	if (uart0_cb.tx_counter < uart0_cb.tx_buffer_length &&
	    !uart0_cb.tx_abort) {
#if	defined(DT_NORDIC_NRF_UART_UART_0_RTS_PIN) && \
		defined(DT_NORDIC_NRF_UART_UART_0_CTS_PIN)
		k_delayed_work_submit(&uart0_cb.tx_timeout_work,
				uart0_cb.tx_timeout);
#endif
		nrf_uart_event_clear(uart0_addr, NRF_UART_EVENT_TXDRDY);

		u8_t txd = uart0_cb.tx_buffer[uart0_cb.tx_counter];

		nrf_uart_txd_set(uart0_addr, txd);
	} else {
#if	defined(DT_NORDIC_NRF_UART_UART_0_RTS_PIN) && \
		defined(DT_NORDIC_NRF_UART_UART_0_CTS_PIN)
		k_delayed_work_cancel(&uart0_cb.tx_timeout_work);
#endif
		nrf_uart_event_clear(uart0_addr, NRF_UART_EVENT_TXDRDY);
		uart0_cb.tx_buffer_length = 0;
		uart0_cb.tx_counter = 0;
		struct uart_event event = {
			.type = UART_TX_DONE,
			.data.tx.buf = uart0_cb.tx_buffer,
			.data.tx.len = uart0_cb.tx_counter
		};
		user_callback(&event);
	}
}

#define UART_ERROR_FROM_MASK(mask) \
	(mask & NRF_UART_ERROR_OVERRUN_MASK ? UART_ERROR_OVERRUN	\
	 : mask & NRF_UART_ERROR_PARITY_MASK ? UART_ERROR_PARITY	\
	 : mask & NRF_UART_ERROR_FRAMING_MASK ? UART_ERROR_FRAMING	\
	 : mask & NRF_UART_ERROR_BREAK_MASK ? UART_BREAK		\
	 : 0)

static void error_isr(struct device *dev)
{
	k_delayed_work_cancel(&uart0_cb.rx_timeout_work);
	nrf_uart_event_clear(uart0_addr, NRF_UART_EVENT_ERROR);

	if (!uart0_cb.rx_enabled) {
		nrf_uart_task_trigger(uart0_addr, NRF_UART_TASK_STOPRX);
	}
	struct uart_event event = {
		.type = UART_RX_STOPPED,
		.data.rx_stop.reason =
			UART_ERROR_FROM_MASK(
				nrf_uart_errorsrc_get_and_clear(uart0_addr)),
		.data.rx_stop.data.len = uart0_cb.rx_counter
					 - uart0_cb.rx_offset,
		.data.rx_stop.data.offset = uart0_cb.rx_offset,
		.data.rx_stop.data.buf = uart0_cb.rx_buffer
	};

	user_callback(&event);
	/* Abort transfer. */
	uart_nrfx_rx_disable(dev);
}

/*
 * In nRF hardware RX timeout can occur only after stopping the peripheral,
 * it is used as a sign that peripheral has finished its operation and is
 * disabled.
 */
static void rxto_isr(void)
{
	nrf_uart_event_clear(uart0_addr, NRF_UART_EVENT_RXTO);

	buf_released_evt();
	if (uart0_cb.rx_secondary_buffer_length) {
		uart0_cb.rx_buffer = uart0_cb.rx_secondary_buffer;
		buf_released_evt();
	}

	rx_reset_state();
	rx_disabled_evt();
}

void uart_nrfx_isr(void *arg)
{
	struct device *uart = (struct device *) arg;

	if (nrf_uart_int_enable_check(uart0_addr, NRF_UART_INT_MASK_ERROR) &&
	    nrf_uart_event_check(uart0_addr, NRF_UART_EVENT_ERROR)) {
		error_isr(uart);
	} else if (nrf_uart_int_enable_check(uart0_addr,
					     NRF_UART_INT_MASK_RXDRDY) &&
		   nrf_uart_event_check(uart0_addr, NRF_UART_EVENT_RXDRDY)) {
		rx_isr(uart);
	}

	if (nrf_uart_event_check(uart0_addr, NRF_UART_EVENT_TXDRDY)) {
		tx_isr();
	}

	if (nrf_uart_event_check(uart0_addr, NRF_UART_EVENT_RXTO)) {
		rxto_isr();
	}
}

static void rx_timeout(struct k_work *work)
{
	rx_rdy_evt();
}
#if	defined(DT_NORDIC_NRF_UART_UART_0_RTS_PIN) && \
	defined(DT_NORDIC_NRF_UART_UART_0_CTS_PIN)
static void tx_timeout(struct k_work *work)
{
	struct uart_event evt;

	k_delayed_work_cancel(&uart0_cb.tx_timeout_work);
	nrf_uart_task_trigger(uart0_addr, NRF_UART_TASK_STOPTX);
	evt.type = UART_TX_ABORTED;
	evt.data.tx.buf = uart0_cb.tx_buffer;
	evt.data.tx.len = uart0_cb.tx_buffer_length;
	uart0_cb.tx_buffer_length = 0;
	uart0_cb.tx_counter = 0;
	user_callback(&evt);

}
#endif

#endif /* CONFIG_UART_0_ASYNC */


#ifdef CONFIG_UART_0_INTERRUPT_DRIVEN

/** Interrupt driven FIFO fill function */
static int uart_nrfx_fifo_fill(struct device *dev,
			       const u8_t *tx_data,
			       int len)
{
	u8_t num_tx = 0U;

	while ((len - num_tx > 0) &&
	       event_txdrdy_check()) {

		/* Clear the interrupt */
		event_txdrdy_clear();

		/* Send a character */
		nrf_uart_txd_set(uart0_addr, (u8_t)tx_data[num_tx++]);
	}

	return (int)num_tx;
}

/** Interrupt driven FIFO read function */
static int uart_nrfx_fifo_read(struct device *dev,
			       u8_t *rx_data,
			       const int size)
{
	u8_t num_rx = 0U;

	while ((size - num_rx > 0) &&
	       nrf_uart_event_check(uart0_addr, NRF_UART_EVENT_RXDRDY)) {
		/* Clear the interrupt */
		nrf_uart_event_clear(uart0_addr, NRF_UART_EVENT_RXDRDY);

		/* Receive a character */
		rx_data[num_rx++] = (u8_t)nrf_uart_rxd_get(uart0_addr);
	}

	return num_rx;
}

/** Interrupt driven transfer enabling function */
static void uart_nrfx_irq_tx_enable(struct device *dev)
{
	u32_t key;

	/* Indicate that this device started a transaction that should not be
	 * interrupted by putting the SoC into the deep sleep mode.
	 */
	device_busy_set(dev);

	/* Activate the transmitter. */
	nrf_uart_task_trigger(uart0_addr, NRF_UART_TASK_STARTTX);

	nrf_uart_int_enable(uart0_addr, NRF_UART_INT_MASK_TXDRDY);

	/* Critical section is used to avoid any UART related interrupt which
	 * can occur after the if statement and before call of the function
	 * forcing an interrupt.
	 */
	key = irq_lock();
	if (uart_sw_event_txdrdy) {
		/* Due to HW limitation first TXDRDY interrupt shall be
		 * triggered by the software.
		 */
		NVIC_SetPendingIRQ(DT_NORDIC_NRF_UART_UART_0_IRQ_0);
	}
	irq_unlock(key);
}

/** Interrupt driven transfer disabling function */
static void uart_nrfx_irq_tx_disable(struct device *dev)
{
	nrf_uart_int_disable(uart0_addr, NRF_UART_INT_MASK_TXDRDY);

	/* Deactivate the transmitter so that it does not needlessly consume
	 * power.
	 */
	nrf_uart_task_trigger(uart0_addr, NRF_UART_TASK_STOPTX);

	/* The transaction is over. It is okay to enter the deep sleep mode
	 * if needed.
	 */
	device_busy_clear(dev);
}

/** Interrupt driven receiver enabling function */
static void uart_nrfx_irq_rx_enable(struct device *dev)
{
	nrf_uart_int_enable(uart0_addr, NRF_UART_INT_MASK_RXDRDY);
}

/** Interrupt driven receiver disabling function */
static void uart_nrfx_irq_rx_disable(struct device *dev)
{
	nrf_uart_int_disable(uart0_addr, NRF_UART_INT_MASK_RXDRDY);
}

/** Interrupt driven transfer empty function */
static int uart_nrfx_irq_tx_ready_complete(struct device *dev)
{
	return event_txdrdy_check();
}

/** Interrupt driven receiver ready function */
static int uart_nrfx_irq_rx_ready(struct device *dev)
{
	return nrf_uart_event_check(uart0_addr, NRF_UART_EVENT_RXDRDY);
}

/** Interrupt driven error enabling function */
static void uart_nrfx_irq_err_enable(struct device *dev)
{
	nrf_uart_int_enable(uart0_addr, NRF_UART_INT_MASK_ERROR);
}

/** Interrupt driven error disabling function */
static void uart_nrfx_irq_err_disable(struct device *dev)
{
	nrf_uart_int_disable(uart0_addr, NRF_UART_INT_MASK_ERROR);
}

/** Interrupt driven pending status function */
static int uart_nrfx_irq_is_pending(struct device *dev)
{
	return ((nrf_uart_int_enable_check(uart0_addr,
					   NRF_UART_INT_MASK_TXDRDY) &&
		 event_txdrdy_check())
		||
		(nrf_uart_int_enable_check(uart0_addr,
					   NRF_UART_INT_MASK_RXDRDY) &&
		 uart_nrfx_irq_rx_ready(dev)));
}

/** Interrupt driven interrupt update function */
static int uart_nrfx_irq_update(struct device *dev)
{
	return 1;
}

/** Set the callback function */
static void uart_nrfx_irq_callback_set(struct device *dev,
				       uart_irq_callback_user_data_t cb,
				       void *cb_data)
{
	(void)dev;
	irq_callback = cb;
	irq_cb_data = cb_data;
}

/**
 * @brief Interrupt service routine.
 *
 * This simply calls the callback function, if one exists.
 *
 * @param arg Argument to ISR.
 *
 * @return N/A
 */
static void uart_nrfx_isr(void *arg)
{
	ARG_UNUSED(arg);

	if (irq_callback) {
		irq_callback(irq_cb_data);
	}
}
#endif /* CONFIG_UART_0_INTERRUPT_DRIVEN */

DEVICE_DECLARE(uart_nrfx_uart0);

/**
 * @brief Initialize UART channel
 *
 * This routine is called to reset the chip in a quiescent state.
 * It is assumed that this function is called only once per UART.
 *
 * @param dev UART device struct
 *
 * @return 0 on success
 */
static int uart_nrfx_init(struct device *dev)
{
	int err;

	/* Setting default height state of the TX PIN to avoid glitches
	 * on the line during peripheral activation/deactivation.
	 */
	nrf_gpio_pin_write(DT_NORDIC_NRF_UART_UART_0_TX_PIN, 1);
	nrf_gpio_cfg_output(DT_NORDIC_NRF_UART_UART_0_TX_PIN);

	nrf_gpio_cfg_input(DT_NORDIC_NRF_UART_UART_0_RX_PIN,
			   NRF_GPIO_PIN_NOPULL);

	nrf_uart_txrx_pins_set(uart0_addr,
			       DT_NORDIC_NRF_UART_UART_0_TX_PIN,
			       DT_NORDIC_NRF_UART_UART_0_RX_PIN);
#if	defined(DT_NORDIC_NRF_UART_UART_0_RTS_PIN) && \
	defined(DT_NORDIC_NRF_UART_UART_0_CTS_PIN)
	/* Setting default height state of the RTS PIN to avoid glitches
	 * on the line during peripheral activation/deactivation.
	 */
	nrf_gpio_pin_write(DT_NORDIC_NRF_UART_UART_0_RTS_PIN, 1);
	nrf_gpio_cfg_output(DT_NORDIC_NRF_UART_UART_0_RTS_PIN);

	nrf_gpio_cfg_input(DT_NORDIC_NRF_UART_UART_0_CTS_PIN,
			   NRF_GPIO_PIN_NOPULL);

	nrf_uart_hwfc_pins_set(uart0_addr,
			       DT_NORDIC_NRF_UART_UART_0_RTS_PIN,
			       DT_NORDIC_NRF_UART_UART_0_CTS_PIN);
#endif

	/* Set initial configuration */
	err = uart_nrfx_configure(dev, &get_dev_data(dev)->uart_config);
	if (err) {
		return err;
	}

	/* Enable the UART and activate its receiver. With the current API
	 * the receiver needs to be active all the time. The transmitter
	 * will be activated when there is something to send.
	 */
	nrf_uart_enable(uart0_addr);

	nrf_uart_event_clear(uart0_addr, NRF_UART_EVENT_RXDRDY);

	nrf_uart_task_trigger(uart0_addr, NRF_UART_TASK_STARTRX);

#ifdef CONFIG_UART_0_INTERRUPT_DRIVEN
	/* Simulate that the TXDRDY event is set, so that the transmitter status
	 * is indicated correctly.
	 */
	uart_sw_event_txdrdy = 1U;
#endif

#if defined(CONFIG_UART_0_ASYNC) || defined(CONFIG_UART_0_INTERRUPT_DRIVEN)

	IRQ_CONNECT(DT_NORDIC_NRF_UART_UART_0_IRQ_0,
		    DT_NORDIC_NRF_UART_UART_0_IRQ_0_PRIORITY,
		    uart_nrfx_isr,
		    DEVICE_GET(uart_nrfx_uart0),
		    0);
	irq_enable(DT_NORDIC_NRF_UART_UART_0_IRQ_0);
#endif

#ifdef CONFIG_UART_0_ASYNC
	k_delayed_work_init(&uart0_cb.rx_timeout_work, rx_timeout);
#if	defined(DT_NORDIC_NRF_UART_UART_0_RTS_PIN) && \
	defined(DT_NORDIC_NRF_UART_UART_0_CTS_PIN)
	k_delayed_work_init(&uart0_cb.tx_timeout_work, tx_timeout);
#endif
#endif
	return 0;
}

/* Common function: uart_nrfx_irq_tx_ready_complete is used for two API entries
 * because Nordic hardware does not distinguish between them.
 */
static const struct uart_driver_api uart_nrfx_uart_driver_api = {
#ifdef CONFIG_UART_0_ASYNC
	.callback_set	  = uart_nrfx_callback_set,
	.tx		  = uart_nrfx_tx,
	.tx_abort	  = uart_nrfx_tx_abort,
	.rx_enable	  = uart_nrfx_rx_enable,
	.rx_buf_rsp	  = uart_nrfx_rx_buf_rsp,
	.rx_disable	  = uart_nrfx_rx_disable,
#endif /* CONFIG_UART_0_ASYNC */
	.poll_in          = uart_nrfx_poll_in,
	.poll_out         = uart_nrfx_poll_out,
	.err_check        = uart_nrfx_err_check,
	.configure        = uart_nrfx_configure,
	.config_get       = uart_nrfx_config_get,
#ifdef CONFIG_UART_0_INTERRUPT_DRIVEN
	.fifo_fill        = uart_nrfx_fifo_fill,
	.fifo_read        = uart_nrfx_fifo_read,
	.irq_tx_enable    = uart_nrfx_irq_tx_enable,
	.irq_tx_disable   = uart_nrfx_irq_tx_disable,
	.irq_tx_ready     = uart_nrfx_irq_tx_ready_complete,
	.irq_rx_enable    = uart_nrfx_irq_rx_enable,
	.irq_rx_disable   = uart_nrfx_irq_rx_disable,
	.irq_tx_complete  = uart_nrfx_irq_tx_ready_complete,
	.irq_rx_ready     = uart_nrfx_irq_rx_ready,
	.irq_err_enable   = uart_nrfx_irq_err_enable,
	.irq_err_disable  = uart_nrfx_irq_err_disable,
	.irq_is_pending   = uart_nrfx_irq_is_pending,
	.irq_update       = uart_nrfx_irq_update,
	.irq_callback_set = uart_nrfx_irq_callback_set,
#endif /* CONFIG_UART_0_INTERRUPT_DRIVEN */
};

#ifdef CONFIG_DEVICE_POWER_MANAGEMENT
static void uart_nrfx_set_power_state(u32_t new_state)
{
	if (new_state == DEVICE_PM_ACTIVE_STATE) {
		nrf_uart_enable(uart0_addr);
		nrf_uart_task_trigger(uart0_addr, NRF_UART_TASK_STARTRX);
	} else {
		assert(new_state == DEVICE_PM_LOW_POWER_STATE ||
		       new_state == DEVICE_PM_SUSPEND_STATE ||
		       new_state == DEVICE_PM_OFF_STATE);
		nrf_uart_disable(uart0_addr);
	}
}

static int uart_nrfx_pm_control(struct device *dev, u32_t ctrl_command,
				void *context, device_pm_cb cb, void *arg)
{
	static u32_t current_state = DEVICE_PM_ACTIVE_STATE;

	if (ctrl_command == DEVICE_PM_SET_POWER_STATE) {
		u32_t new_state = *((const u32_t *)context);

		if (new_state != current_state) {
			uart_nrfx_set_power_state(new_state);
			current_state = new_state;
		}
	} else {
		assert(ctrl_command == DEVICE_PM_GET_POWER_STATE);
		*((u32_t *)context) = current_state;
	}

	if (cb) {
		cb(dev, 0, context, arg);
	}

	return 0;
}
#endif /* CONFIG_DEVICE_POWER_MANAGEMENT */

static struct uart_nrfx_data uart_nrfx_uart0_data = {
	.uart_config = {
		.stop_bits = UART_CFG_STOP_BITS_1,
		.data_bits = UART_CFG_DATA_BITS_8,
		.baudrate  = DT_NORDIC_NRF_UART_UART_0_CURRENT_SPEED,
#ifdef CONFIG_UART_0_NRF_PARITY_BIT
		.parity    = UART_CFG_PARITY_EVEN,
#else
		.parity    = UART_CFG_PARITY_NONE,
#endif /* CONFIG_UART_0_NRF_PARITY_BIT */
#ifdef CONFIG_UART_0_NRF_FLOW_CONTROL
		.flow_ctrl = UART_CFG_FLOW_CTRL_RTS_CTS,
#else
		.flow_ctrl = UART_CFG_FLOW_CTRL_NONE,
#endif /* CONFIG_UART_0_NRF_FLOW_CONTROL */
	}
};

static const struct uart_nrfx_config uart_nrfx_uart0_config = {
#if	defined(DT_NORDIC_NRF_UART_UART_0_RTS_PIN) && \
	defined(DT_NORDIC_NRF_UART_UART_0_CTS_PIN)
	.rts_cts_pins_set = true,
#else
	.rts_cts_pins_set = false,
#endif
};

DEVICE_DEFINE(uart_nrfx_uart0,
	      DT_NORDIC_NRF_UART_UART_0_LABEL,
	      uart_nrfx_init,
	      uart_nrfx_pm_control,
	      &uart_nrfx_uart0_data,
	      &uart_nrfx_uart0_config,
	      /* Initialize UART device before UART console. */
	      PRE_KERNEL_1,
	      CONFIG_KERNEL_INIT_PRIORITY_DEVICE,
	      &uart_nrfx_uart_driver_api);