Training courses

Kernel and Embedded Linux

Bootlin training courses

Embedded Linux, kernel,
Yocto Project, Buildroot, real-time,
graphics, boot time, debugging...

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
// SPDX-License-Identifier: GPL-2.0+

/*
 * Multifunction core driver for Zodiac Inflight Innovations RAVE
 * Supervisory Processor(SP) MCU that is connected via dedicated UART
 * port
 *
 * Copyright (C) 2017 Zodiac Inflight Innovations
 */

#include <linux/atomic.h>
#include <linux/crc-ccitt.h>
#include <linux/delay.h>
#include <linux/export.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/kernel.h>
#include <linux/mfd/rave-sp.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/of_device.h>
#include <linux/sched.h>
#include <linux/serdev.h>
#include <asm/unaligned.h>

/*
 * UART protocol using following entities:
 *  - message to MCU => ACK response
 *  - event from MCU => event ACK
 *
 * Frame structure:
 * <STX> <DATA> <CHECKSUM> <ETX>
 * Where:
 * - STX - is start of transmission character
 * - ETX - end of transmission
 * - DATA - payload
 * - CHECKSUM - checksum calculated on <DATA>
 *
 * If <DATA> or <CHECKSUM> contain one of control characters, then it is
 * escaped using <DLE> control code. Added <DLE> does not participate in
 * checksum calculation.
 */
#define RAVE_SP_STX			0x02
#define RAVE_SP_ETX			0x03
#define RAVE_SP_DLE			0x10

#define RAVE_SP_MAX_DATA_SIZE		64
#define RAVE_SP_CHECKSUM_8B2C		1
#define RAVE_SP_CHECKSUM_CCITT		2
#define RAVE_SP_CHECKSUM_SIZE		RAVE_SP_CHECKSUM_CCITT
/*
 * We don't store STX, ETX and unescaped bytes, so Rx is only
 * DATA + CSUM
 */
#define RAVE_SP_RX_BUFFER_SIZE				\
	(RAVE_SP_MAX_DATA_SIZE + RAVE_SP_CHECKSUM_SIZE)

#define RAVE_SP_STX_ETX_SIZE		2
/*
 * For Tx we have to have space for everything, STX, EXT and
 * potentially stuffed DATA + CSUM data + csum
 */
#define RAVE_SP_TX_BUFFER_SIZE				\
	(RAVE_SP_STX_ETX_SIZE + 2 * RAVE_SP_RX_BUFFER_SIZE)

/**
 * enum rave_sp_deframer_state - Possible state for de-framer
 *
 * @RAVE_SP_EXPECT_SOF:		 Scanning input for start-of-frame marker
 * @RAVE_SP_EXPECT_DATA:	 Got start of frame marker, collecting frame
 * @RAVE_SP_EXPECT_ESCAPED_DATA: Got escape character, collecting escaped byte
 */
enum rave_sp_deframer_state {
	RAVE_SP_EXPECT_SOF,
	RAVE_SP_EXPECT_DATA,
	RAVE_SP_EXPECT_ESCAPED_DATA,
};

/**
 * struct rave_sp_deframer - Device protocol deframer
 *
 * @state:  Current state of the deframer
 * @data:   Buffer used to collect deframed data
 * @length: Number of bytes de-framed so far
 */
struct rave_sp_deframer {
	enum rave_sp_deframer_state state;
	unsigned char data[RAVE_SP_RX_BUFFER_SIZE];
	size_t length;
};

/**
 * struct rave_sp_reply - Reply as per RAVE device protocol
 *
 * @length:	Expected reply length
 * @data:	Buffer to store reply payload in
 * @code:	Expected reply code
 * @ackid:	Expected reply ACK ID
 * @completion: Successful reply reception completion
 */
struct rave_sp_reply {
	size_t length;
	void  *data;
	u8     code;
	u8     ackid;
	struct completion received;
};

/**
 * struct rave_sp_checksum - Variant specific checksum implementation details
 *
 * @length:	Calculated checksum length
 * @subroutine:	Utilized checksum algorithm implementation
 */
struct rave_sp_checksum {
	size_t length;
	void (*subroutine)(const u8 *, size_t, u8 *);
};

struct rave_sp_version {
	u8     hardware;
	__le16 major;
	u8     minor;
	u8     letter[2];
} __packed;

struct rave_sp_status {
	struct rave_sp_version bootloader_version;
	struct rave_sp_version firmware_version;
	u16 rdu_eeprom_flag;
	u16 dds_eeprom_flag;
	u8  pic_flag;
	u8  orientation;
	u32 etc;
	s16 temp[2];
	u8  backlight_current[3];
	u8  dip_switch;
	u8  host_interrupt;
	u16 voltage_28;
	u8  i2c_device_status;
	u8  power_status;
	u8  general_status;
	u8  deprecated1;
	u8  power_led_status;
	u8  deprecated2;
	u8  periph_power_shutoff;
} __packed;

/**
 * struct rave_sp_variant_cmds - Variant specific command routines
 *
 * @translate:	Generic to variant specific command mapping routine
 * @get_status: Variant specific implementation of CMD_GET_STATUS
 */
struct rave_sp_variant_cmds {
	int (*translate)(enum rave_sp_command);
	int (*get_status)(struct rave_sp *sp, struct rave_sp_status *);
};

/**
 * struct rave_sp_variant - RAVE supervisory processor core variant
 *
 * @checksum:	Variant specific checksum implementation
 * @cmd:	Variant specific command pointer table
 *
 */
struct rave_sp_variant {
	const struct rave_sp_checksum *checksum;
	struct rave_sp_variant_cmds cmd;
};

/**
 * struct rave_sp - RAVE supervisory processor core
 *
 * @serdev:			Pointer to underlying serdev
 * @deframer:			Stored state of the protocol deframer
 * @ackid:			ACK ID used in last reply sent to the device
 * @bus_lock:			Lock to serialize access to the device
 * @reply_lock:			Lock protecting @reply
 * @reply:			Pointer to memory to store reply payload
 *
 * @variant:			Device variant specific information
 * @event_notifier_list:	Input event notification chain
 *
 * @part_number_firmware:	Firmware version
 * @part_number_bootloader:	Bootloader version
 */
struct rave_sp {
	struct serdev_device *serdev;
	struct rave_sp_deframer deframer;
	atomic_t ackid;
	struct mutex bus_lock;
	struct mutex reply_lock;
	struct rave_sp_reply *reply;

	const struct rave_sp_variant *variant;
	struct blocking_notifier_head event_notifier_list;

	const char *part_number_firmware;
	const char *part_number_bootloader;
};

static bool rave_sp_id_is_event(u8 code)
{
	return (code & 0xF0) == RAVE_SP_EVNT_BASE;
}

static void rave_sp_unregister_event_notifier(struct device *dev, void *res)
{
	struct rave_sp *sp = dev_get_drvdata(dev->parent);
	struct notifier_block *nb = *(struct notifier_block **)res;
	struct blocking_notifier_head *bnh = &sp->event_notifier_list;

	WARN_ON(blocking_notifier_chain_unregister(bnh, nb));
}

int devm_rave_sp_register_event_notifier(struct device *dev,
					 struct notifier_block *nb)
{
	struct rave_sp *sp = dev_get_drvdata(dev->parent);
	struct notifier_block **rcnb;
	int ret;

	rcnb = devres_alloc(rave_sp_unregister_event_notifier,
			    sizeof(*rcnb), GFP_KERNEL);
	if (!rcnb)
		return -ENOMEM;

	ret = blocking_notifier_chain_register(&sp->event_notifier_list, nb);
	if (!ret) {
		*rcnb = nb;
		devres_add(dev, rcnb);
	} else {
		devres_free(rcnb);
	}

	return ret;
}
EXPORT_SYMBOL_GPL(devm_rave_sp_register_event_notifier);

static void csum_8b2c(const u8 *buf, size_t size, u8 *crc)
{
	*crc = *buf++;
	size--;

	while (size--)
		*crc += *buf++;

	*crc = 1 + ~(*crc);
}

static void csum_ccitt(const u8 *buf, size_t size, u8 *crc)
{
	const u16 calculated = crc_ccitt_false(0xffff, buf, size);

	/*
	 * While the rest of the wire protocol is little-endian,
	 * CCITT-16 CRC in RDU2 device is sent out in big-endian order.
	 */
	put_unaligned_be16(calculated, crc);
}

static void *stuff(unsigned char *dest, const unsigned char *src, size_t n)
{
	while (n--) {
		const unsigned char byte = *src++;

		switch (byte) {
		case RAVE_SP_STX:
		case RAVE_SP_ETX:
		case RAVE_SP_DLE:
			*dest++ = RAVE_SP_DLE;
			/* FALLTHROUGH */
		default:
			*dest++ = byte;
		}
	}

	return dest;
}

static int rave_sp_write(struct rave_sp *sp, const u8 *data, u8 data_size)
{
	const size_t checksum_length = sp->variant->checksum->length;
	unsigned char frame[RAVE_SP_TX_BUFFER_SIZE];
	unsigned char crc[RAVE_SP_CHECKSUM_SIZE];
	unsigned char *dest = frame;
	size_t length;

	if (WARN_ON(checksum_length > sizeof(crc)))
		return -ENOMEM;

	if (WARN_ON(data_size > sizeof(frame)))
		return -ENOMEM;

	sp->variant->checksum->subroutine(data, data_size, crc);

	*dest++ = RAVE_SP_STX;
	dest = stuff(dest, data, data_size);
	dest = stuff(dest, crc, checksum_length);
	*dest++ = RAVE_SP_ETX;

	length = dest - frame;

	print_hex_dump_debug("rave-sp tx: ", DUMP_PREFIX_NONE,
			     16, 1, frame, length, false);

	return serdev_device_write(sp->serdev, frame, length, HZ);
}

static u8 rave_sp_reply_code(u8 command)
{
	/*
	 * There isn't a single rule that describes command code ->
	 * ACK code transformation, but, going through various
	 * versions of ICDs, there appear to be three distinct groups
	 * that can be described by simple transformation.
	 */
	switch (command) {
	case 0xA0 ... 0xBE:
		/*
		 * Commands implemented by firmware found in RDU1 and
		 * older devices all seem to obey the following rule
		 */
		return command + 0x20;
	case 0xE0 ... 0xEF:
		/*
		 * Events emitted by all versions of the firmare use
		 * least significant bit to get an ACK code
		 */
		return command | 0x01;
	default:
		/*
		 * Commands implemented by firmware found in RDU2 are
		 * similar to "old" commands, but they use slightly
		 * different offset
		 */
		return command + 0x40;
	}
}

int rave_sp_exec(struct rave_sp *sp,
		 void *__data,  size_t data_size,
		 void *reply_data, size_t reply_data_size)
{
	struct rave_sp_reply reply = {
		.data     = reply_data,
		.length   = reply_data_size,
		.received = COMPLETION_INITIALIZER_ONSTACK(reply.received),
	};
	unsigned char *data = __data;
	int command, ret = 0;
	u8 ackid;

	command = sp->variant->cmd.translate(data[0]);
	if (command < 0)
		return command;

	ackid       = atomic_inc_return(&sp->ackid);
	reply.ackid = ackid;
	reply.code  = rave_sp_reply_code((u8)command),

	mutex_lock(&sp->bus_lock);

	mutex_lock(&sp->reply_lock);
	sp->reply = &reply;
	mutex_unlock(&sp->reply_lock);

	data[0] = command;
	data[1] = ackid;

	rave_sp_write(sp, data, data_size);

	if (!wait_for_completion_timeout(&reply.received, HZ)) {
		dev_err(&sp->serdev->dev, "Command timeout\n");
		ret = -ETIMEDOUT;

		mutex_lock(&sp->reply_lock);
		sp->reply = NULL;
		mutex_unlock(&sp->reply_lock);
	}

	mutex_unlock(&sp->bus_lock);
	return ret;
}
EXPORT_SYMBOL_GPL(rave_sp_exec);

static void rave_sp_receive_event(struct rave_sp *sp,
				  const unsigned char *data, size_t length)
{
	u8 cmd[] = {
		[0] = rave_sp_reply_code(data[0]),
		[1] = data[1],
	};

	rave_sp_write(sp, cmd, sizeof(cmd));

	blocking_notifier_call_chain(&sp->event_notifier_list,
				     rave_sp_action_pack(data[0], data[2]),
				     NULL);
}

static void rave_sp_receive_reply(struct rave_sp *sp,
				  const unsigned char *data, size_t length)
{
	struct device *dev = &sp->serdev->dev;
	struct rave_sp_reply *reply;
	const  size_t payload_length = length - 2;

	mutex_lock(&sp->reply_lock);
	reply = sp->reply;

	if (reply) {
		if (reply->code == data[0] && reply->ackid == data[1] &&
		    payload_length >= reply->length) {
			/*
			 * We are relying on memcpy(dst, src, 0) to be a no-op
			 * when handling commands that have a no-payload reply
			 */
			memcpy(reply->data, &data[2], reply->length);
			complete(&reply->received);
			sp->reply = NULL;
		} else {
			dev_err(dev, "Ignoring incorrect reply\n");
			dev_dbg(dev, "Code:   expected = 0x%08x received = 0x%08x\n",
				reply->code, data[0]);
			dev_dbg(dev, "ACK ID: expected = 0x%08x received = 0x%08x\n",
				reply->ackid, data[1]);
			dev_dbg(dev, "Length: expected = %zu received = %zu\n",
				reply->length, payload_length);
		}
	}

	mutex_unlock(&sp->reply_lock);
}

static void rave_sp_receive_frame(struct rave_sp *sp,
				  const unsigned char *data,
				  size_t length)
{
	const size_t checksum_length = sp->variant->checksum->length;
	const size_t payload_length  = length - checksum_length;
	const u8 *crc_reported       = &data[payload_length];
	struct device *dev           = &sp->serdev->dev;
	u8 crc_calculated[RAVE_SP_CHECKSUM_SIZE];

	if (unlikely(checksum_length > sizeof(crc_calculated))) {
		dev_warn(dev, "Checksum too long, dropping\n");
		return;
	}

	print_hex_dump_debug("rave-sp rx: ", DUMP_PREFIX_NONE,
			     16, 1, data, length, false);

	if (unlikely(length <= checksum_length)) {
		dev_warn(dev, "Dropping short frame\n");
		return;
	}

	sp->variant->checksum->subroutine(data, payload_length,
					  crc_calculated);

	if (memcmp(crc_calculated, crc_reported, checksum_length)) {
		dev_warn(dev, "Dropping bad frame\n");
		return;
	}

	if (rave_sp_id_is_event(data[0]))
		rave_sp_receive_event(sp, data, length);
	else
		rave_sp_receive_reply(sp, data, length);
}

static int rave_sp_receive_buf(struct serdev_device *serdev,
			       const unsigned char *buf, size_t size)
{
	struct device *dev = &serdev->dev;
	struct rave_sp *sp = dev_get_drvdata(dev);
	struct rave_sp_deframer *deframer = &sp->deframer;
	const unsigned char *src = buf;
	const unsigned char *end = buf + size;

	while (src < end) {
		const unsigned char byte = *src++;

		switch (deframer->state) {
		case RAVE_SP_EXPECT_SOF:
			if (byte == RAVE_SP_STX)
				deframer->state = RAVE_SP_EXPECT_DATA;
			break;

		case RAVE_SP_EXPECT_DATA:
			/*
			 * Treat special byte values first
			 */
			switch (byte) {
			case RAVE_SP_ETX:
				rave_sp_receive_frame(sp,
						      deframer->data,
						      deframer->length);
				/*
				 * Once we extracted a complete frame
				 * out of a stream, we call it done
				 * and proceed to bailing out while
				 * resetting the framer to initial
				 * state, regardless if we've consumed
				 * all of the stream or not.
				 */
				goto reset_framer;
			case RAVE_SP_STX:
				dev_warn(dev, "Bad frame: STX before ETX\n");
				/*
				 * If we encounter second "start of
				 * the frame" marker before seeing
				 * corresponding "end of frame", we
				 * reset the framer and ignore both:
				 * frame started by first SOF and
				 * frame started by current SOF.
				 *
				 * NOTE: The above means that only the
				 * frame started by third SOF, sent
				 * after this one will have a chance
				 * to get throught.
				 */
				goto reset_framer;
			case RAVE_SP_DLE:
				deframer->state = RAVE_SP_EXPECT_ESCAPED_DATA;
				/*
				 * If we encounter escape sequence we
				 * need to skip it and collect the
				 * byte that follows. We do it by
				 * forcing the next iteration of the
				 * encompassing while loop.
				 */
				continue;
			}
			/*
			 * For the rest of the bytes, that are not
			 * speical snoflakes, we do the same thing
			 * that we do to escaped data - collect it in
			 * deframer buffer
			 */

			/* FALLTHROUGH */

		case RAVE_SP_EXPECT_ESCAPED_DATA:
			if (deframer->length == sizeof(deframer->data)) {
				dev_warn(dev, "Bad frame: Too long\n");
				/*
				 * If the amount of data we've
				 * accumulated for current frame so
				 * far starts to exceed the capacity
				 * of deframer's buffer, there's
				 * nothing else we can do but to
				 * discard that data and start
				 * assemblying a new frame again
				 */
				goto reset_framer;
			}

			deframer->data[deframer->length++] = byte;

			/*
			 * We've extracted out special byte, now we
			 * can go back to regular data collecting
			 */
			deframer->state = RAVE_SP_EXPECT_DATA;
			break;
		}
	}

	/*
	 * The only way to get out of the above loop and end up here
	 * is throught consuming all of the supplied data, so here we
	 * report that we processed it all.
	 */
	return size;

reset_framer:
	/*
	 * NOTE: A number of codepaths that will drop us here will do
	 * so before consuming all 'size' bytes of the data passed by
	 * serdev layer. We rely on the fact that serdev layer will
	 * re-execute this handler with the remainder of the Rx bytes
	 * once we report actual number of bytes that we processed.
	 */
	deframer->state  = RAVE_SP_EXPECT_SOF;
	deframer->length = 0;

	return src - buf;
}

static int rave_sp_rdu1_cmd_translate(enum rave_sp_command command)
{
	if (command >= RAVE_SP_CMD_STATUS &&
	    command <= RAVE_SP_CMD_CONTROL_EVENTS)
		return command;

	return -EINVAL;
}

static int rave_sp_rdu2_cmd_translate(enum rave_sp_command command)
{
	if (command >= RAVE_SP_CMD_GET_FIRMWARE_VERSION &&
	    command <= RAVE_SP_CMD_GET_GPIO_STATE)
		return command;

	if (command == RAVE_SP_CMD_REQ_COPPER_REV) {
		/*
		 * As per RDU2 ICD 3.4.47 CMD_GET_COPPER_REV code is
		 * different from that for RDU1 and it is set to 0x28.
		 */
		return 0x28;
	}

	return rave_sp_rdu1_cmd_translate(command);
}

static int rave_sp_default_cmd_translate(enum rave_sp_command command)
{
	/*
	 * All of the following command codes were taken from "Table :
	 * Communications Protocol Message Types" in section 3.3
	 * "MESSAGE TYPES" of Rave PIC24 ICD.
	 */
	switch (command) {
	case RAVE_SP_CMD_GET_FIRMWARE_VERSION:
		return 0x11;
	case RAVE_SP_CMD_GET_BOOTLOADER_VERSION:
		return 0x12;
	case RAVE_SP_CMD_BOOT_SOURCE:
		return 0x14;
	case RAVE_SP_CMD_SW_WDT:
		return 0x1C;
	case RAVE_SP_CMD_PET_WDT:
		return 0x1D;
	case RAVE_SP_CMD_RESET:
		return 0x1E;
	case RAVE_SP_CMD_RESET_REASON:
		return 0x1F;
	case RAVE_SP_CMD_RMB_EEPROM:
		return 0x20;
	default:
		return -EINVAL;
	}
}

static const char *devm_rave_sp_version(struct device *dev,
					struct rave_sp_version *version)
{
	/*
	 * NOTE: The format string below uses %02d to display u16
	 * intentionally for the sake of backwards compatibility with
	 * legacy software.
	 */
	return devm_kasprintf(dev, GFP_KERNEL, "%02d%02d%02d.%c%c\n",
			      version->hardware,
			      le16_to_cpu(version->major),
			      version->minor,
			      version->letter[0],
			      version->letter[1]);
}

static int rave_sp_rdu1_get_status(struct rave_sp *sp,
				   struct rave_sp_status *status)
{
	u8 cmd[] = {
		[0] = RAVE_SP_CMD_STATUS,
		[1] = 0
	};

	return rave_sp_exec(sp, cmd, sizeof(cmd), status, sizeof(*status));
}

static int rave_sp_emulated_get_status(struct rave_sp *sp,
				       struct rave_sp_status *status)
{
	u8 cmd[] = {
		[0] = RAVE_SP_CMD_GET_FIRMWARE_VERSION,
		[1] = 0,
	};
	int ret;

	ret = rave_sp_exec(sp, cmd, sizeof(cmd), &status->firmware_version,
			   sizeof(status->firmware_version));
	if (ret)
		return ret;

	cmd[0] = RAVE_SP_CMD_GET_BOOTLOADER_VERSION;
	return rave_sp_exec(sp, cmd, sizeof(cmd), &status->bootloader_version,
			    sizeof(status->bootloader_version));
}

static int rave_sp_get_status(struct rave_sp *sp)
{
	struct device *dev = &sp->serdev->dev;
	struct rave_sp_status status;
	const char *version;
	int ret;

	ret = sp->variant->cmd.get_status(sp, &status);
	if (ret)
		return ret;

	version = devm_rave_sp_version(dev, &status.firmware_version);
	if (!version)
		return -ENOMEM;

	sp->part_number_firmware = version;

	version = devm_rave_sp_version(dev, &status.bootloader_version);
	if (!version)
		return -ENOMEM;

	sp->part_number_bootloader = version;

	return 0;
}

static const struct rave_sp_checksum rave_sp_checksum_8b2c = {
	.length     = 1,
	.subroutine = csum_8b2c,
};

static const struct rave_sp_checksum rave_sp_checksum_ccitt = {
	.length     = 2,
	.subroutine = csum_ccitt,
};

static const struct rave_sp_variant rave_sp_legacy = {
	.checksum = &rave_sp_checksum_ccitt,
	.cmd = {
		.translate = rave_sp_default_cmd_translate,
		.get_status = rave_sp_emulated_get_status,
	},
};

static const struct rave_sp_variant rave_sp_rdu1 = {
	.checksum = &rave_sp_checksum_8b2c,
	.cmd = {
		.translate = rave_sp_rdu1_cmd_translate,
		.get_status = rave_sp_rdu1_get_status,
	},
};

static const struct rave_sp_variant rave_sp_rdu2 = {
	.checksum = &rave_sp_checksum_ccitt,
	.cmd = {
		.translate = rave_sp_rdu2_cmd_translate,
		.get_status = rave_sp_emulated_get_status,
	},
};

static const struct of_device_id rave_sp_dt_ids[] = {
	{ .compatible = "zii,rave-sp-niu",  .data = &rave_sp_legacy },
	{ .compatible = "zii,rave-sp-mezz", .data = &rave_sp_legacy },
	{ .compatible = "zii,rave-sp-esb",  .data = &rave_sp_legacy },
	{ .compatible = "zii,rave-sp-rdu1", .data = &rave_sp_rdu1   },
	{ .compatible = "zii,rave-sp-rdu2", .data = &rave_sp_rdu2   },
	{ /* sentinel */ }
};

static const struct serdev_device_ops rave_sp_serdev_device_ops = {
	.receive_buf  = rave_sp_receive_buf,
	.write_wakeup = serdev_device_write_wakeup,
};

static int rave_sp_probe(struct serdev_device *serdev)
{
	struct device *dev = &serdev->dev;
	const char *unknown = "unknown\n";
	struct rave_sp *sp;
	u32 baud;
	int ret;

	if (of_property_read_u32(dev->of_node, "current-speed", &baud)) {
		dev_err(dev,
			"'current-speed' is not specified in device node\n");
		return -EINVAL;
	}

	sp = devm_kzalloc(dev, sizeof(*sp), GFP_KERNEL);
	if (!sp)
		return -ENOMEM;

	sp->serdev = serdev;
	dev_set_drvdata(dev, sp);

	sp->variant = of_device_get_match_data(dev);
	if (!sp->variant)
		return -ENODEV;

	mutex_init(&sp->bus_lock);
	mutex_init(&sp->reply_lock);
	BLOCKING_INIT_NOTIFIER_HEAD(&sp->event_notifier_list);

	serdev_device_set_client_ops(serdev, &rave_sp_serdev_device_ops);
	ret = devm_serdev_device_open(dev, serdev);
	if (ret)
		return ret;

	serdev_device_set_baudrate(serdev, baud);
	serdev_device_set_flow_control(serdev, false);

	ret = serdev_device_set_parity(serdev, SERDEV_PARITY_NONE);
	if (ret) {
		dev_err(dev, "Failed to set parity\n");
		return ret;
	}

	ret = rave_sp_get_status(sp);
	if (ret) {
		dev_warn(dev, "Failed to get firmware status: %d\n", ret);
		sp->part_number_firmware   = unknown;
		sp->part_number_bootloader = unknown;
	}

	/*
	 * Those strings already have a \n embedded, so there's no
	 * need to have one in format string.
	 */
	dev_info(dev, "Firmware version: %s",   sp->part_number_firmware);
	dev_info(dev, "Bootloader version: %s", sp->part_number_bootloader);

	return devm_of_platform_populate(dev);
}

MODULE_DEVICE_TABLE(of, rave_sp_dt_ids);

static struct serdev_device_driver rave_sp_drv = {
	.probe			= rave_sp_probe,
	.driver = {
		.name		= "rave-sp",
		.of_match_table	= rave_sp_dt_ids,
	},
};
module_serdev_device_driver(rave_sp_drv);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Andrey Vostrikov <andrey.vostrikov@cogentembedded.com>");
MODULE_AUTHOR("Nikita Yushchenko <nikita.yoush@cogentembedded.com>");
MODULE_AUTHOR("Andrey Smirnov <andrew.smirnov@gmail.com>");
MODULE_DESCRIPTION("RAVE SP core driver");