Linux Audio

Check our new training course

Loading...
  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
/* h4.c - H:4 UART based Bluetooth driver */

/*
 * Copyright (c) 2015-2016 Intel Corporation
 *
 * SPDX-License-Identifier: Apache-2.0
 */

#include <errno.h>
#include <stddef.h>

#include <zephyr.h>
#include <arch/cpu.h>

#include <init.h>
#include <uart.h>
#include <misc/util.h>
#include <misc/byteorder.h>
#include <string.h>

#include <bluetooth/bluetooth.h>
#include <bluetooth/hci.h>
#include <bluetooth/hci_driver.h>

#define BT_DBG_ENABLED IS_ENABLED(CONFIG_BT_DEBUG_HCI_DRIVER)
#define LOG_MODULE_NAME bt_driver
#include "common/log.h"

#include "../util.h"

#if defined(CONFIG_BT_NRF51_PM)
#include "../nrf51_pm.h"
#endif

#define H4_NONE 0x00
#define H4_CMD  0x01
#define H4_ACL  0x02
#define H4_SCO  0x03
#define H4_EVT  0x04

static K_THREAD_STACK_DEFINE(rx_thread_stack, CONFIG_BT_RX_STACK_SIZE);
static struct k_thread rx_thread_data;

static struct {
	struct net_buf *buf;
	struct k_fifo   fifo;

	u16_t    remaining;
	u16_t    discard;

	bool     have_hdr;
	bool     discardable;

	u8_t     hdr_len;

	u8_t     type;
	union {
		struct bt_hci_evt_hdr evt;
		struct bt_hci_acl_hdr acl;
		u8_t hdr[4];
	};
} rx = {
	.fifo = Z_FIFO_INITIALIZER(rx.fifo),
};

static struct {
	u8_t type;
	struct net_buf *buf;
	struct k_fifo   fifo;
} tx = {
	.fifo = Z_FIFO_INITIALIZER(tx.fifo),
};

static struct device *h4_dev;

static inline void h4_get_type(void)
{
	/* Get packet type */
	if (uart_fifo_read(h4_dev, &rx.type, 1) != 1) {
		BT_WARN("Unable to read H:4 packet type");
		rx.type = H4_NONE;
		return;
	}

	switch (rx.type) {
	case H4_EVT:
		rx.remaining = sizeof(rx.evt);
		rx.hdr_len = rx.remaining;
		break;
	case H4_ACL:
		rx.remaining = sizeof(rx.acl);
		rx.hdr_len = rx.remaining;
		break;
	default:
		BT_ERR("Unknown H:4 type 0x%02x", rx.type);
		rx.type = H4_NONE;
	}
}

static inline void get_acl_hdr(void)
{
	struct bt_hci_acl_hdr *hdr = &rx.acl;
	int to_read = sizeof(*hdr) - rx.remaining;

	rx.remaining -= uart_fifo_read(h4_dev, (u8_t *)hdr + to_read,
				       rx.remaining);
	if (!rx.remaining) {
		rx.remaining = sys_le16_to_cpu(hdr->len);
		BT_DBG("Got ACL header. Payload %u bytes", rx.remaining);
		rx.have_hdr = true;
	}
}

static inline void get_evt_hdr(void)
{
	struct bt_hci_evt_hdr *hdr = &rx.evt;
	int to_read = rx.hdr_len - rx.remaining;

	rx.remaining -= uart_fifo_read(h4_dev, (u8_t *)hdr + to_read,
				       rx.remaining);
	if (rx.hdr_len == sizeof(*hdr) && rx.remaining < sizeof(*hdr)) {
		switch (rx.evt.evt) {
		case BT_HCI_EVT_LE_META_EVENT:
			rx.remaining++;
			rx.hdr_len++;
			break;
#if defined(CONFIG_BT_BREDR)
		case BT_HCI_EVT_INQUIRY_RESULT_WITH_RSSI:
		case BT_HCI_EVT_EXTENDED_INQUIRY_RESULT:
			rx.discardable = true;
			break;
#endif
		}
	}

	if (!rx.remaining) {
		if (rx.evt.evt == BT_HCI_EVT_LE_META_EVENT &&
		    rx.hdr[sizeof(*hdr)] == BT_HCI_EVT_LE_ADVERTISING_REPORT) {
			BT_DBG("Marking adv report as discardable");
			rx.discardable = true;
		}

		rx.remaining = hdr->len - (rx.hdr_len - sizeof(*hdr));
		BT_DBG("Got event header. Payload %u bytes", hdr->len);
		rx.have_hdr = true;
	}
}


static inline void copy_hdr(struct net_buf *buf)
{
	net_buf_add_mem(buf, rx.hdr, rx.hdr_len);
}

static void reset_rx(void)
{
	rx.type = H4_NONE;
	rx.remaining = 0U;
	rx.have_hdr = false;
	rx.hdr_len = 0U;
	rx.discardable = false;
}

static struct net_buf *get_rx(int timeout)
{
	BT_DBG("type 0x%02x, evt 0x%02x", rx.type, rx.evt.evt);

	if (rx.type == H4_EVT) {
		return bt_buf_get_evt(rx.evt.evt, rx.discardable, timeout);
	}

	return bt_buf_get_rx(BT_BUF_ACL_IN, timeout);
}

static void rx_thread(void *p1, void *p2, void *p3)
{
	struct net_buf *buf;

	ARG_UNUSED(p1);
	ARG_UNUSED(p2);
	ARG_UNUSED(p3);

	BT_DBG("started");

	while (1) {
		BT_DBG("rx.buf %p", rx.buf);

		/* We can only do the allocation if we know the initial
		 * header, since Command Complete/Status events must use the
		 * original command buffer (if available).
		 */
		if (rx.have_hdr && !rx.buf) {
			rx.buf = get_rx(K_FOREVER);
			BT_DBG("Got rx.buf %p", rx.buf);
			if (rx.remaining > net_buf_tailroom(rx.buf)) {
				BT_ERR("Not enough space in buffer");
				rx.discard = rx.remaining;
				reset_rx();
			} else {
				copy_hdr(rx.buf);
			}
		}

		/* Let the ISR continue receiving new packets */
		uart_irq_rx_enable(h4_dev);

		buf = net_buf_get(&rx.fifo, K_FOREVER);
		do {
			uart_irq_rx_enable(h4_dev);

			BT_DBG("Calling bt_recv(%p)", buf);
			bt_recv(buf);

			/* Give other threads a chance to run if the ISR
			 * is receiving data so fast that rx.fifo never
			 * or very rarely goes empty.
			 */
			k_yield();

			uart_irq_rx_disable(h4_dev);
			buf = net_buf_get(&rx.fifo, K_NO_WAIT);
		} while (buf);
	}
}

static size_t h4_discard(struct device *uart, size_t len)
{
	u8_t buf[33];

	return uart_fifo_read(uart, buf, MIN(len, sizeof(buf)));
}

static inline void read_payload(void)
{
	struct net_buf *buf;
	bool prio;
	int read;

	if (!rx.buf) {
		rx.buf = get_rx(K_NO_WAIT);
		if (!rx.buf) {
			if (rx.discardable) {
				BT_WARN("Discarding event 0x%02x", rx.evt.evt);
				rx.discard = rx.remaining;
				reset_rx();
				return;
			}

			BT_WARN("Failed to allocate, deferring to rx_thread");
			uart_irq_rx_disable(h4_dev);
			return;
		}

		BT_DBG("Allocated rx.buf %p", rx.buf);

		if (rx.remaining > net_buf_tailroom(rx.buf)) {
			BT_ERR("Not enough space in buffer");
			rx.discard = rx.remaining;
			reset_rx();
			return;
		}

		copy_hdr(rx.buf);
	}

	read = uart_fifo_read(h4_dev, net_buf_tail(rx.buf), rx.remaining);
	net_buf_add(rx.buf, read);
	rx.remaining -= read;

	BT_DBG("got %d bytes, remaining %u", read, rx.remaining);
	BT_DBG("Payload (len %u): %s", rx.buf->len,
	       bt_hex(rx.buf->data, rx.buf->len));

	if (rx.remaining) {
		return;
	}

	prio = (rx.type == H4_EVT && bt_hci_evt_is_prio(rx.evt.evt));

	buf = rx.buf;
	rx.buf = NULL;

	if (rx.type == H4_EVT) {
		bt_buf_set_type(buf, BT_BUF_EVT);
	} else {
		bt_buf_set_type(buf, BT_BUF_ACL_IN);
	}

	reset_rx();

	if (prio) {
		BT_DBG("Calling bt_recv_prio(%p)", buf);
		bt_recv_prio(buf);
	} else {
		BT_DBG("Putting buf %p to rx fifo", buf);
		net_buf_put(&rx.fifo, buf);
	}
}

static inline void read_header(void)
{
	switch (rx.type) {
	case H4_NONE:
		h4_get_type();
		return;
	case H4_EVT:
		get_evt_hdr();
		break;
	case H4_ACL:
		get_acl_hdr();
		break;
	default:
		CODE_UNREACHABLE;
		return;
	}

	if (rx.have_hdr && rx.buf) {
		if (rx.remaining > net_buf_tailroom(rx.buf)) {
			BT_ERR("Not enough space in buffer");
			rx.discard = rx.remaining;
			reset_rx();
		} else {
			copy_hdr(rx.buf);
		}
	}
}

static inline void process_tx(void)
{
	int bytes;

	if (!tx.buf) {
		tx.buf = net_buf_get(&tx.fifo, K_NO_WAIT);
		if (!tx.buf) {
			BT_ERR("TX interrupt but no pending buffer!");
			uart_irq_tx_disable(h4_dev);
			return;
		}
	}

	if (!tx.type) {
		switch (bt_buf_get_type(tx.buf)) {
		case BT_BUF_ACL_OUT:
			tx.type = H4_ACL;
			break;
		case BT_BUF_CMD:
			tx.type = H4_CMD;
			break;
		default:
			BT_ERR("Unknown buffer type");
			goto done;
		}

		bytes = uart_fifo_fill(h4_dev, &tx.type, 1);
		if (bytes != 1) {
			BT_WARN("Unable to send H:4 type");
			tx.type = H4_NONE;
			return;
		}
	}

	bytes = uart_fifo_fill(h4_dev, tx.buf->data, tx.buf->len);
	net_buf_pull(tx.buf, bytes);

	if (tx.buf->len) {
		return;
	}

done:
	tx.type = H4_NONE;
	net_buf_unref(tx.buf);
	tx.buf = net_buf_get(&tx.fifo, K_NO_WAIT);
	if (!tx.buf) {
		uart_irq_tx_disable(h4_dev);
	}
}

static inline void process_rx(void)
{
	BT_DBG("remaining %u discard %u have_hdr %u rx.buf %p len %u",
	       rx.remaining, rx.discard, rx.have_hdr, rx.buf,
	       rx.buf ? rx.buf->len : 0);

	if (rx.discard) {
		rx.discard -= h4_discard(h4_dev, rx.discard);
		return;
	}

	if (rx.have_hdr) {
		read_payload();
	} else {
		read_header();
	}
}

static void bt_uart_isr(struct device *unused)
{
	ARG_UNUSED(unused);

	while (uart_irq_update(h4_dev) && uart_irq_is_pending(h4_dev)) {
		if (uart_irq_tx_ready(h4_dev)) {
			process_tx();
		}

		if (uart_irq_rx_ready(h4_dev)) {
			process_rx();
		}
	}
}

static int h4_send(struct net_buf *buf)
{
	BT_DBG("buf %p type %u len %u", buf, bt_buf_get_type(buf), buf->len);

	net_buf_put(&tx.fifo, buf);
	uart_irq_tx_enable(h4_dev);

	return 0;
}

static int h4_open(void)
{
	BT_DBG("");

	uart_irq_rx_disable(h4_dev);
	uart_irq_tx_disable(h4_dev);

#if defined(CONFIG_BT_NRF51_PM)
	if (nrf51_init(h4_dev) < 0) {
		return -EIO;
	}
#else
	h4_discard(h4_dev, 32);
#endif

	uart_irq_callback_set(h4_dev, bt_uart_isr);

	k_thread_create(&rx_thread_data, rx_thread_stack,
			K_THREAD_STACK_SIZEOF(rx_thread_stack),
			rx_thread, NULL, NULL, NULL,
			K_PRIO_COOP(CONFIG_BT_RX_PRIO),
			0, K_NO_WAIT);

	return 0;
}

static const struct bt_hci_driver drv = {
	.name		= "H:4",
	.bus		= BT_HCI_DRIVER_BUS_UART,
	.open		= h4_open,
	.send		= h4_send,
};

static int bt_uart_init(struct device *unused)
{
	ARG_UNUSED(unused);

	h4_dev = device_get_binding(CONFIG_BT_UART_ON_DEV_NAME);
	if (!h4_dev) {
		return -EINVAL;
	}

	bt_hci_driver_register(&drv);

	return 0;
}

SYS_INIT(bt_uart_init, POST_KERNEL, CONFIG_KERNEL_INIT_PRIORITY_DEVICE);