xref: /btstack/src/hci_transport_h4.c (revision d4d8445570fbeab6a48c397749444927f1b272ee)
1 /*
2  * Copyright (C) 2014 BlueKitchen GmbH
3  *
4  * Redistribution and use in source and binary forms, with or without
5  * modification, are permitted provided that the following conditions
6  * are met:
7  *
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer.
10  * 2. Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in the
12  *    documentation and/or other materials provided with the distribution.
13  * 3. Neither the name of the copyright holders nor the names of
14  *    contributors may be used to endorse or promote products derived
15  *    from this software without specific prior written permission.
16  * 4. Any redistribution, use, or modification is done solely for
17  *    personal benefit and not for any commercial purpose or for
18  *    monetary gain.
19  *
20  * THIS SOFTWARE IS PROVIDED BY BLUEKITCHEN GMBH AND CONTRIBUTORS
21  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
22  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
23  * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL MATTHIAS
24  * RINGWALD OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
25  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
26  * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
27  * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
28  * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
29  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF
30  * THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31  * SUCH DAMAGE.
32  *
33  * Please inquire about commercial licensing options at
34  * [email protected]
35  *
36  */
37 
38 #define __BTSTACK_FILE__ "hci_transport_h4.c"
39 
40 /*
41  *  hci_h4_transport.c
42  *
43  *  HCI Transport API implementation for H4 protocol over POSIX with optional support for eHCILL
44  *
45  *  Created by Matthias Ringwald on 4/29/09.
46  */
47 
48 #include <inttypes.h>
49 
50 #include "btstack_config.h"
51 
52 #include "btstack_debug.h"
53 #include "hci.h"
54 #include "hci_transport.h"
55 #include "bluetooth_company_id.h"
56 #include "btstack_uart_block.h"
57 
58 #define ENABLE_LOG_EHCILL
59 
60 #ifdef ENABLE_EHCILL
61 
62 // eHCILL commands
63 enum EHCILL_MESSAGES {
64 	EHCILL_GO_TO_SLEEP_IND = 0x030,
65 	EHCILL_GO_TO_SLEEP_ACK = 0x031,
66 	EHCILL_WAKE_UP_IND     = 0x032,
67 	EHCILL_WAKE_UP_ACK     = 0x033,
68 	EHCILL_WAKEUP_SIGNAL   = 0x034,
69 };
70 
71 static int  hci_transport_h4_ehcill_outgoing_packet_ready(void);
72 static void hci_transport_h4_echill_send_wakeup_ind(void);
73 static void hci_transport_h4_ehcill_handle_command(uint8_t action);
74 static void hci_transport_h4_ehcill_handle_ehcill_command_sent(void);
75 static void hci_transport_h4_ehcill_handle_packet_sent(void);
76 static void hci_transport_h4_ehcill_open(void);
77 static void hci_transport_h4_ehcill_reset_statemachine(void);
78 static void hci_transport_h4_ehcill_send_ehcill_command(void);
79 static void hci_transport_h4_ehcill_sleep_ack_timer_setup(void);
80 static void hci_transport_h4_ehcill_trigger_wakeup(void);
81 
82 typedef enum {
83     EHCILL_STATE_W2_SEND_SLEEP_ACK,
84     EHCILL_STATE_SLEEP,
85     EHCILL_STATE_W4_WAKEUP_IND_OR_ACK,
86     EHCILL_STATE_AWAKE
87 } EHCILL_STATE;
88 
89 // eHCILL state machine
90 static EHCILL_STATE ehcill_state;
91 static uint8_t      ehcill_command_to_send;
92 
93 static btstack_uart_sleep_mode_t btstack_uart_sleep_mode;
94 
95 // work around for eHCILL problem
96 static btstack_timer_source_t ehcill_sleep_ack_timer;
97 
98 #endif
99 
100 
101 // assert pre-buffer for packet type is available
102 #if !defined(HCI_OUTGOING_PRE_BUFFER_SIZE) || (HCI_OUTGOING_PRE_BUFFER_SIZE == 0)
103 #error HCI_OUTGOING_PRE_BUFFER_SIZE not defined. Please update hci.h
104 #endif
105 
106 static void dummy_handler(uint8_t packet_type, uint8_t *packet, uint16_t size);
107 
108 typedef enum {
109     H4_W4_PACKET_TYPE,
110     H4_W4_EVENT_HEADER,
111     H4_W4_ACL_HEADER,
112     H4_W4_SCO_HEADER,
113     H4_W4_PAYLOAD,
114 } H4_STATE;
115 
116 typedef enum {
117     TX_IDLE = 1,
118     TX_W4_PACKET_SENT,
119 #ifdef ENABLE_EHCILL
120     TX_W4_WAKEUP,
121     TX_W2_EHCILL_SEND,
122     TX_W4_EHCILL_SENT,
123 #endif
124 } TX_STATE;
125 
126 // UART Driver + Config
127 static const btstack_uart_block_t * btstack_uart;
128 static btstack_uart_config_t uart_config;
129 
130 // write state
131 static TX_STATE tx_state;
132 static uint8_t * tx_data;
133 static uint16_t  tx_len;   // 0 == no outgoing packet
134 
135 static uint8_t packet_sent_event[] = { HCI_EVENT_TRANSPORT_PACKET_SENT, 0};
136 
137 static  void (*packet_handler)(uint8_t packet_type, uint8_t *packet, uint16_t size) = dummy_handler;
138 
139 // packet reader state machine
140 static  H4_STATE h4_state;
141 static int bytes_to_read;
142 static int read_pos;
143 
144 // incoming packet buffer
145 static uint8_t hci_packet_with_pre_buffer[HCI_INCOMING_PRE_BUFFER_SIZE + 1 + HCI_PACKET_BUFFER_SIZE]; // packet type + max(acl header + acl payload, event header + event data)
146 static uint8_t * hci_packet = &hci_packet_with_pre_buffer[HCI_INCOMING_PRE_BUFFER_SIZE];
147 
148 #ifdef ENABLE_CC256X_BAUDRATE_CHANGE_FLOWCONTROL_BUG_WORKAROUND
149 static const uint8_t local_version_event_prefix[] = { 0x04, 0x0e, 0x0c, 0x01, 0x01, 0x10};
150 static const uint8_t baud_rate_command_prefix[]   = { 0x01, 0x36, 0xff, 0x04};
151 static enum {
152     CC256X_WORKAROUND_IDLE,
153     CC256X_WORKAROUND_CHIPSET_DETECTED,
154     CC256X_WORKAROUND_BAUDRATE_COMMAND_SENT,
155     CC256X_WORKAROUND_DONE
156 } cc256x_workaround_state;
157 #endif
158 
159 static int hci_transport_h4_set_baudrate(uint32_t baudrate){
160     log_info("hci_transport_h4_set_baudrate %"PRIu32, baudrate);
161     return btstack_uart->set_baudrate(baudrate);
162 }
163 
164 static void hci_transport_h4_reset_statemachine(void){
165     h4_state = H4_W4_PACKET_TYPE;
166     read_pos = 0;
167     bytes_to_read = 1;
168 }
169 
170 static void hci_transport_h4_trigger_next_read(void){
171     // log_info("hci_transport_h4_trigger_next_read: %u bytes", bytes_to_read);
172     btstack_uart->receive_block(&hci_packet[read_pos], bytes_to_read);
173 }
174 
175 static void hci_transport_h4_block_read(void){
176 
177     read_pos += bytes_to_read;
178 
179     switch (h4_state) {
180         case H4_W4_PACKET_TYPE:
181             switch (hci_packet[0]){
182                 case HCI_EVENT_PACKET:
183                     bytes_to_read = HCI_EVENT_HEADER_SIZE;
184                     h4_state = H4_W4_EVENT_HEADER;
185                     break;
186                 case HCI_ACL_DATA_PACKET:
187                     bytes_to_read = HCI_ACL_HEADER_SIZE;
188                     h4_state = H4_W4_ACL_HEADER;
189                     break;
190                 case HCI_SCO_DATA_PACKET:
191                     bytes_to_read = HCI_SCO_HEADER_SIZE;
192                     h4_state = H4_W4_SCO_HEADER;
193                     break;
194 #ifdef ENABLE_EHCILL
195                 case EHCILL_GO_TO_SLEEP_IND:
196                 case EHCILL_GO_TO_SLEEP_ACK:
197                 case EHCILL_WAKE_UP_IND:
198                 case EHCILL_WAKE_UP_ACK:
199                     hci_transport_h4_ehcill_handle_command(hci_packet[0]);
200                     hci_transport_h4_reset_statemachine();
201                     break;
202 #endif
203                 default:
204                     log_error("hci_transport_h4: invalid packet type 0x%02x", hci_packet[0]);
205                     hci_transport_h4_reset_statemachine();
206                     break;
207             }
208             break;
209 
210         case H4_W4_EVENT_HEADER:
211             bytes_to_read = hci_packet[2];
212             h4_state = H4_W4_PAYLOAD;
213             break;
214 
215         case H4_W4_ACL_HEADER:
216             bytes_to_read = little_endian_read_16( hci_packet, 3);
217             // check ACL length
218             if (HCI_ACL_HEADER_SIZE + bytes_to_read >  HCI_PACKET_BUFFER_SIZE){
219                 log_error("hci_transport_h4: invalid ACL payload len %d - only space for %u", bytes_to_read, HCI_PACKET_BUFFER_SIZE - HCI_ACL_HEADER_SIZE);
220                 hci_transport_h4_reset_statemachine();
221                 break;
222             }
223             h4_state = H4_W4_PAYLOAD;
224             break;
225 
226         case H4_W4_SCO_HEADER:
227             bytes_to_read = hci_packet[3];
228             h4_state = H4_W4_PAYLOAD;
229             break;
230 
231         case H4_W4_PAYLOAD:
232 #ifdef ENABLE_CC256X_BAUDRATE_CHANGE_FLOWCONTROL_BUG_WORKAROUND
233             if (cc256x_workaround_state == CC256X_WORKAROUND_IDLE
234             && memcmp(hci_packet, local_version_event_prefix, sizeof(local_version_event_prefix)) == 0){
235                 if (little_endian_read_16(hci_packet, 11) == BLUETOOTH_COMPANY_ID_TEXAS_INSTRUMENTS_INC){
236                     // detect TI CC256x controller based on manufacturer
237                     log_info("Detected CC256x controller");
238                     cc256x_workaround_state = CC256X_WORKAROUND_CHIPSET_DETECTED;
239                 } else {
240                     // work around not needed
241                     log_info("Bluetooth controller not by TI");
242                     cc256x_workaround_state = CC256X_WORKAROUND_DONE;
243                 }
244             }
245 #endif
246             packet_handler(hci_packet[0], &hci_packet[1], read_pos-1);
247             hci_transport_h4_reset_statemachine();
248             break;
249         default:
250             break;
251     }
252 
253 #ifdef ENABLE_CC256X_BAUDRATE_CHANGE_FLOWCONTROL_BUG_WORKAROUND
254     if (cc256x_workaround_state == CC256X_WORKAROUND_BAUDRATE_COMMAND_SENT){
255         cc256x_workaround_state = CC256X_WORKAROUND_IDLE;
256         // avoid flowcontrol problem by reading expected hci command complete event of 7 bytes in a single block read
257         h4_state = H4_W4_PAYLOAD;
258         bytes_to_read = 7;
259     }
260 #endif
261 
262     hci_transport_h4_trigger_next_read();
263 }
264 
265 static void hci_transport_h4_block_sent(void){
266     switch (tx_state){
267         case TX_W4_PACKET_SENT:
268             // packet fully sent, reset state
269             tx_len = 0;
270             tx_state = TX_IDLE;
271 
272 #ifdef ENABLE_EHCILL
273             // notify eHCILL engine
274             hci_transport_h4_ehcill_handle_packet_sent();
275 #endif
276             // notify upper stack that it can send again
277             packet_handler(HCI_EVENT_PACKET, &packet_sent_event[0], sizeof(packet_sent_event));
278             break;
279 
280 #ifdef ENABLE_EHCILL
281         case TX_W4_EHCILL_SENT:
282         case TX_W4_WAKEUP:
283             hci_transport_h4_ehcill_handle_ehcill_command_sent();
284             break;
285 #endif
286 
287         default:
288             break;
289     }
290 }
291 
292 static int hci_transport_h4_can_send_now(uint8_t packet_type){
293     return tx_state == TX_IDLE;
294 }
295 
296 static int hci_transport_h4_send_packet(uint8_t packet_type, uint8_t * packet, int size){
297 
298     // store packet type before actual data and increase size
299     size++;
300     packet--;
301     *packet = packet_type;
302 
303 #ifdef ENABLE_CC256X_BAUDRATE_CHANGE_FLOWCONTROL_BUG_WORKAROUND
304     if ((cc256x_workaround_state == CC256X_WORKAROUND_CHIPSET_DETECTED)
305     && (memcmp(packet, baud_rate_command_prefix, sizeof(baud_rate_command_prefix)) == 0)) {
306         log_info("CC256x baud rate command detected, expect command complete event next");
307         cc256x_workaround_state = CC256X_WORKAROUND_BAUDRATE_COMMAND_SENT;
308     }
309 #endif
310 
311     // store request
312     tx_len   = size;
313     tx_data  = packet;
314 
315 #ifdef ENABLE_EHCILL
316     switch (ehcill_state){
317         case EHCILL_STATE_SLEEP:
318             hci_transport_h4_ehcill_trigger_wakeup();
319             return 0;
320         case EHCILL_STATE_W2_SEND_SLEEP_ACK:
321             log_info("eHILL: send next packet, state EHCILL_STATE_W2_SEND_SLEEP_ACK");
322             return 0;
323         default:
324             break;
325     }
326 #endif
327 
328     // start sending
329     tx_state = TX_W4_PACKET_SENT;
330     btstack_uart->send_block(packet, size);
331     return 0;
332 }
333 
334 static void hci_transport_h4_init(const void * transport_config){
335     // check for hci_transport_config_uart_t
336     if (!transport_config) {
337         log_error("hci_transport_h4: no config!");
338         return;
339     }
340     if (((hci_transport_config_t*)transport_config)->type != HCI_TRANSPORT_CONFIG_UART) {
341         log_error("hci_transport_h4: config not of type != HCI_TRANSPORT_CONFIG_UART!");
342         return;
343     }
344 
345     // extract UART config from transport config
346     hci_transport_config_uart_t * hci_transport_config_uart = (hci_transport_config_uart_t*) transport_config;
347     uart_config.baudrate    = hci_transport_config_uart->baudrate_init;
348     uart_config.flowcontrol = hci_transport_config_uart->flowcontrol;
349     uart_config.device_name = hci_transport_config_uart->device_name;
350 
351     // setup UART driver
352     btstack_uart->init(&uart_config);
353     btstack_uart->set_block_received(&hci_transport_h4_block_read);
354     btstack_uart->set_block_sent(&hci_transport_h4_block_sent);
355 }
356 
357 static int hci_transport_h4_open(void){
358     int res = btstack_uart->open();
359     if (res){
360         return res;
361     }
362     hci_transport_h4_reset_statemachine();
363     hci_transport_h4_trigger_next_read();
364 
365     tx_state = TX_IDLE;
366 
367 #ifdef ENABLE_EHCILL
368     hci_transport_h4_ehcill_open();
369 #endif
370     return 0;
371 }
372 
373 static int hci_transport_h4_close(void){
374     return btstack_uart->close();
375 }
376 
377 static void hci_transport_h4_register_packet_handler(void (*handler)(uint8_t packet_type, uint8_t *packet, uint16_t size)){
378     packet_handler = handler;
379 }
380 
381 static void dummy_handler(uint8_t packet_type, uint8_t *packet, uint16_t size){
382 }
383 
384 //
385 // --- main part of eHCILL implementation ---
386 //
387 
388 #ifdef ENABLE_EHCILL
389 
390 static void hci_transport_h4_ehcill_emit_sleep_state(int sleep_active){
391     static int last_state = 0;
392     if (sleep_active == last_state) return;
393     last_state = sleep_active;
394 
395     log_info("hci_transport_h4_ehcill_emit_sleep_state: %u", sleep_active);
396     uint8_t event[3];
397     event[0] = HCI_EVENT_TRANSPORT_SLEEP_MODE;
398     event[1] = sizeof(event) - 2;
399     event[2] = sleep_active;
400     packet_handler(HCI_EVENT_PACKET, &event[0], sizeof(event));
401 }
402 
403 static void hci_transport_h4_ehcill_wakeup_handler(void){
404 #ifdef ENABLE_LOG_EHCILL
405     log_info("eHCILL: UART wakeup received");
406 #endif
407     hci_transport_h4_ehcill_handle_command(EHCILL_WAKEUP_SIGNAL);
408 }
409 
410 static void hci_transport_h4_ehcill_open(void){
411     hci_transport_h4_ehcill_reset_statemachine();
412 
413     // find best sleep mode to use: wake on CTS, wake on RX, none
414     btstack_uart_sleep_mode = BTSTACK_UART_SLEEP_OFF;
415     int supported_sleep_modes = 0;
416     if (btstack_uart->get_supported_sleep_modes){
417         supported_sleep_modes = btstack_uart->get_supported_sleep_modes();
418     }
419     if (supported_sleep_modes & BTSTACK_UART_SLEEP_MASK_RTS_HIGH_WAKE_ON_CTS_PULSE){
420         log_info("eHCILL: using wake on CTS");
421         btstack_uart_sleep_mode = BTSTACK_UART_SLEEP_RTS_HIGH_WAKE_ON_CTS_PULSE;
422     } else if (supported_sleep_modes & BTSTACK_UART_SLEEP_MASK_RTS_LOW_WAKE_ON_RX_EDGE){
423         log_info("eHCILL: using wake on RX");
424         btstack_uart_sleep_mode = BTSTACK_UART_SLEEP_RTS_LOW_WAKE_ON_RX_EDGE;
425     } else {
426         log_info("eHCILL: UART driver does not provide compatible sleep mode");
427     }
428     if (btstack_uart->set_wakeup_handler){
429         btstack_uart->set_wakeup_handler(&hci_transport_h4_ehcill_wakeup_handler);
430     }
431 }
432 
433 static void hci_transport_h4_echill_send_wakeup_ind(void){
434 #ifdef ENABLE_LOG_EHCILL
435     log_info("eHCILL: send WAKEUP_IND");
436 #endif
437     // update state
438     tx_state     = TX_W4_WAKEUP;
439     ehcill_state = EHCILL_STATE_W4_WAKEUP_IND_OR_ACK;
440     ehcill_command_to_send = EHCILL_WAKE_UP_IND;
441     btstack_uart->send_block(&ehcill_command_to_send, 1);
442 }
443 
444 static int hci_transport_h4_ehcill_outgoing_packet_ready(void){
445     return tx_len != 0;
446 }
447 
448 static void hci_transport_h4_ehcill_reset_statemachine(void){
449     ehcill_state = EHCILL_STATE_AWAKE;
450 }
451 
452 static void hci_transport_h4_ehcill_send_ehcill_command(void){
453 #ifdef ENABLE_LOG_EHCILL
454     log_info("eHCILL: send command %02x", ehcill_command_to_send);
455 #endif
456     tx_state = TX_W4_EHCILL_SENT;
457     if (ehcill_command_to_send == EHCILL_GO_TO_SLEEP_ACK){
458         ehcill_state = EHCILL_STATE_SLEEP;
459     }
460     btstack_uart->send_block(&ehcill_command_to_send, 1);
461 }
462 
463 static void hci_transport_h4_ehcill_sleep_ack_timer_handler(btstack_timer_source_t * timer){
464 	UNUSED(timer);
465 #ifdef ENABLE_LOG_EHCILL
466     log_info("eHCILL: timer triggered");
467 #endif
468     hci_transport_h4_ehcill_send_ehcill_command();
469 }
470 
471 static void hci_transport_h4_ehcill_sleep_ack_timer_setup(void){
472     // setup timer
473 #ifdef ENABLE_LOG_EHCILL
474     log_info("eHCILL: set timer for sending command %02x", ehcill_command_to_send);
475 #endif
476     btstack_run_loop_set_timer_handler(&ehcill_sleep_ack_timer, &hci_transport_h4_ehcill_sleep_ack_timer_handler);
477     btstack_run_loop_set_timer(&ehcill_sleep_ack_timer, 50);
478     btstack_run_loop_add_timer(&ehcill_sleep_ack_timer);
479 }
480 
481 static void hci_transport_h4_ehcill_trigger_wakeup(void){
482     switch (tx_state){
483         case TX_W2_EHCILL_SEND:
484         case TX_W4_EHCILL_SENT:
485             // wake up / sleep ack in progress, nothing to do now
486             return;
487         case TX_IDLE:
488         default:
489             // all clear, prepare for wakeup
490             break;
491     }
492     // UART needed again
493     hci_transport_h4_ehcill_emit_sleep_state(0);
494     if (btstack_uart_sleep_mode){
495         btstack_uart->set_sleep(BTSTACK_UART_SLEEP_OFF);
496     }
497     hci_transport_h4_echill_send_wakeup_ind();
498 }
499 
500 static void hci_transport_h4_ehcill_schedule_ehcill_command(uint8_t command){
501 #ifdef ENABLE_LOG_EHCILL
502     log_info("eHCILL: schedule eHCILL command %02x", command);
503 #endif
504     ehcill_command_to_send = command;
505     switch (tx_state){
506         case TX_IDLE:
507             if (ehcill_command_to_send == EHCILL_WAKE_UP_ACK){
508                 // send right away
509                 hci_transport_h4_ehcill_send_ehcill_command();
510             } else {
511                 // change state so BTstack cannot send and setup timer
512                 tx_state = TX_W2_EHCILL_SEND;
513                 hci_transport_h4_ehcill_sleep_ack_timer_setup();
514             }
515             break;
516         default:
517             break;
518     }
519 }
520 
521 static void hci_transport_h4_ehcill_handle_command(uint8_t action){
522     // log_info("hci_transport_h4_ehcill_handle: %x, state %u, defer_rx %u", action, ehcill_state, ehcill_defer_rx_size);
523     switch(ehcill_state){
524         case EHCILL_STATE_AWAKE:
525             switch(action){
526                 case EHCILL_GO_TO_SLEEP_IND:
527                     ehcill_state = EHCILL_STATE_W2_SEND_SLEEP_ACK;
528 #ifdef ENABLE_LOG_EHCILL
529                     log_info("eHCILL: Received GO_TO_SLEEP_IND RX");
530 #endif
531                     hci_transport_h4_ehcill_schedule_ehcill_command(EHCILL_GO_TO_SLEEP_ACK);
532                     break;
533                 default:
534                     break;
535             }
536             break;
537 
538         case EHCILL_STATE_W2_SEND_SLEEP_ACK:
539             switch(action){
540                 case EHCILL_WAKE_UP_IND:
541                     ehcill_state = EHCILL_STATE_AWAKE;
542                     hci_transport_h4_ehcill_emit_sleep_state(0);
543                     if (btstack_uart_sleep_mode){
544                         btstack_uart->set_sleep(BTSTACK_UART_SLEEP_OFF);
545                     }
546 #ifdef ENABLE_LOG_EHCILL
547                     log_info("eHCILL: Received WAKE_UP_IND RX");
548 #endif
549                     hci_transport_h4_ehcill_schedule_ehcill_command(EHCILL_WAKE_UP_ACK);
550                     break;
551 
552                 default:
553                     break;
554             }
555             break;
556 
557         case EHCILL_STATE_SLEEP:
558             switch(action){
559                 case EHCILL_WAKEUP_SIGNAL:
560                     hci_transport_h4_ehcill_emit_sleep_state(0);
561                     if (btstack_uart_sleep_mode){
562                         btstack_uart->set_sleep(BTSTACK_UART_SLEEP_OFF);
563                     }
564                     break;
565                 case EHCILL_WAKE_UP_IND:
566                     ehcill_state = EHCILL_STATE_AWAKE;
567                     hci_transport_h4_ehcill_emit_sleep_state(0);
568                     if (btstack_uart_sleep_mode){
569                         btstack_uart->set_sleep(BTSTACK_UART_SLEEP_OFF);
570                     }
571 #ifdef ENABLE_LOG_EHCILL
572                     log_info("eHCILL: Received WAKE_UP_IND RX");
573 #endif
574                     hci_transport_h4_ehcill_schedule_ehcill_command(EHCILL_WAKE_UP_ACK);
575                     break;
576 
577                 default:
578                     break;
579             }
580             break;
581 
582         case EHCILL_STATE_W4_WAKEUP_IND_OR_ACK:
583             switch(action){
584                 case EHCILL_WAKE_UP_IND:
585                 case EHCILL_WAKE_UP_ACK:
586 #ifdef ENABLE_LOG_EHCILL
587                     log_info("eHCILL: Received WAKE_UP (%02x)", action);
588 #endif
589                     tx_state = TX_W4_PACKET_SENT;
590                     ehcill_state = EHCILL_STATE_AWAKE;
591                     btstack_uart->send_block(tx_data, tx_len);
592                     break;
593                 default:
594                     break;
595             }
596             break;
597     }
598 }
599 
600 static void hci_transport_h4_ehcill_handle_packet_sent(void){
601 #ifdef ENABLE_LOG_EHCILL
602         log_info("eHCILL: handle packet sent, command to send %02x", ehcill_command_to_send);
603 #endif
604     // now, send pending ehcill command if neccessary
605     switch (ehcill_command_to_send){
606         case EHCILL_GO_TO_SLEEP_ACK:
607             hci_transport_h4_ehcill_sleep_ack_timer_setup();
608             break;
609         case EHCILL_WAKE_UP_IND:
610             hci_transport_h4_ehcill_send_ehcill_command();
611             break;
612         default:
613             break;
614     }
615 }
616 
617 static void hci_transport_h4_ehcill_handle_ehcill_command_sent(void){
618     tx_state = TX_IDLE;
619     int command = ehcill_command_to_send;
620     ehcill_command_to_send = 0;
621 
622 #ifdef ENABLE_LOG_EHCILL
623         log_info("eHCILL: handle eHCILL sent, command was %02x", command);
624 #endif
625 
626     if (command == EHCILL_GO_TO_SLEEP_ACK) {
627 #ifdef ENABLE_LOG_EHCILL
628         log_info("eHCILL: GO_TO_SLEEP_ACK sent, enter sleep mode");
629 #endif
630         // UART not needed after EHCILL_GO_TO_SLEEP_ACK was sent
631         if (btstack_uart_sleep_mode != BTSTACK_UART_SLEEP_OFF){
632             btstack_uart->set_sleep(btstack_uart_sleep_mode);
633         }
634         hci_transport_h4_ehcill_emit_sleep_state(1);
635     }
636     // already packet ready? then start wakeup
637     if (hci_transport_h4_ehcill_outgoing_packet_ready()){
638         hci_transport_h4_ehcill_emit_sleep_state(0);
639         if (btstack_uart_sleep_mode != BTSTACK_UART_SLEEP_OFF){
640             btstack_uart->set_sleep(BTSTACK_UART_SLEEP_OFF);
641         }
642         if (command != EHCILL_WAKE_UP_IND){
643             hci_transport_h4_echill_send_wakeup_ind();
644         }
645     }
646 }
647 
648 #endif
649 // --- end of eHCILL implementation ---------
650 
651 static const hci_transport_t hci_transport_h4 = {
652     /* const char * name; */                                        "H4",
653     /* void   (*init) (const void *transport_config); */            &hci_transport_h4_init,
654     /* int    (*open)(void); */                                     &hci_transport_h4_open,
655     /* int    (*close)(void); */                                    &hci_transport_h4_close,
656     /* void   (*register_packet_handler)(void (*handler)(...); */   &hci_transport_h4_register_packet_handler,
657     /* int    (*can_send_packet_now)(uint8_t packet_type); */       &hci_transport_h4_can_send_now,
658     /* int    (*send_packet)(...); */                               &hci_transport_h4_send_packet,
659     /* int    (*set_baudrate)(uint32_t baudrate); */                &hci_transport_h4_set_baudrate,
660     /* void   (*reset_link)(void); */                               NULL,
661     /* void   (*set_sco_config)(uint16_t voice_setting, int num_connections); */ NULL,
662 };
663 
664 // configure and return h4 singleton
665 const hci_transport_t * hci_transport_h4_instance(const btstack_uart_block_t * uart_driver) {
666     btstack_uart = uart_driver;
667     return &hci_transport_h4;
668 }
669