xref: /btstack/src/hci_transport_h4.c (revision c682b8ecdf36f0aa32447eda8a8b375e942ed579)
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_OFF,
110     H4_W4_PACKET_TYPE,
111     H4_W4_EVENT_HEADER,
112     H4_W4_ACL_HEADER,
113     H4_W4_SCO_HEADER,
114     H4_W4_PAYLOAD,
115 } H4_STATE;
116 
117 typedef enum {
118     TX_OFF,
119     TX_IDLE,
120     TX_W4_PACKET_SENT,
121 #ifdef ENABLE_EHCILL
122     TX_W4_WAKEUP,
123     TX_W2_EHCILL_SEND,
124     TX_W4_EHCILL_SENT,
125 #endif
126 } TX_STATE;
127 
128 // UART Driver + Config
129 static const btstack_uart_block_t * btstack_uart;
130 static btstack_uart_config_t uart_config;
131 
132 // write state
133 static TX_STATE tx_state;
134 #ifdef ENABLE_EHCILL
135 static uint8_t * ehcill_tx_data;
136 static uint16_t  ehcill_tx_len;   // 0 == no outgoing packet
137 #endif
138 
139 static uint8_t packet_sent_event[] = { HCI_EVENT_TRANSPORT_PACKET_SENT, 0};
140 
141 static  void (*packet_handler)(uint8_t packet_type, uint8_t *packet, uint16_t size) = dummy_handler;
142 
143 // packet reader state machine
144 static  H4_STATE h4_state;
145 static uint16_t bytes_to_read;
146 static uint16_t read_pos;
147 
148 // incoming packet buffer
149 static uint8_t hci_packet_with_pre_buffer[HCI_INCOMING_PRE_BUFFER_SIZE + HCI_INCOMING_PACKET_BUFFER_SIZE + 1]; // packet type + max(acl header + acl payload, event header + event data)
150 static uint8_t * hci_packet = &hci_packet_with_pre_buffer[HCI_INCOMING_PRE_BUFFER_SIZE];
151 
152 // Baudrate change bugs in TI CC256x and CYW20704
153 #ifdef ENABLE_CC256X_BAUDRATE_CHANGE_FLOWCONTROL_BUG_WORKAROUND
154 #define ENABLE_BAUDRATE_CHANGE_FLOWCONTROL_BUG_WORKAROUND
155 static const uint8_t baud_rate_command_prefix[]   = { 0x01, 0x36, 0xff, 0x04};
156 #endif
157 
158 #ifdef ENABLE_CYPRESS_BAUDRATE_CHANGE_FLOWCONTROL_BUG_WORKAROUND
159 #ifdef ENABLE_BAUDRATE_CHANGE_FLOWCONTROL_BUG_WORKAROUND
160 #error "Please enable either ENABLE_CC256X_BAUDRATE_CHANGE_FLOWCONTROL_BUG_WORKAROUND or ENABLE_BAUDRATE_CHANGE_FLOWCONTROL_BUG_WORKAROUND"
161 #endif
162 #define ENABLE_BAUDRATE_CHANGE_FLOWCONTROL_BUG_WORKAROUND
163 static const uint8_t baud_rate_command_prefix[]   = { 0x01, 0x18, 0xfc, 0x06};
164 #endif
165 
166 #ifdef ENABLE_BAUDRATE_CHANGE_FLOWCONTROL_BUG_WORKAROUND
167 static const uint8_t local_version_event_prefix[] = { 0x04, 0x0e, 0x0c, 0x01, 0x01, 0x10};
168 static enum {
169     BAUDRATE_CHANGE_WORKAROUND_IDLE,
170     BAUDRATE_CHANGE_WORKAROUND_CHIPSET_DETECTED,
171     BAUDRATE_CHANGE_WORKAROUND_BAUDRATE_COMMAND_SENT,
172     BAUDRATE_CHANGE_WORKAROUND_DONE
173 } baudrate_change_workaround_state;
174 #endif
175 
176 static int hci_transport_h4_set_baudrate(uint32_t baudrate){
177     log_info("hci_transport_h4_set_baudrate %"PRIu32, baudrate);
178     return btstack_uart->set_baudrate(baudrate);
179 }
180 
181 static void hci_transport_h4_reset_statemachine(void){
182     h4_state = H4_W4_PACKET_TYPE;
183     read_pos = 0;
184     bytes_to_read = 1;
185 }
186 
187 static void hci_transport_h4_trigger_next_read(void){
188     // log_info("hci_transport_h4_trigger_next_read: %u bytes", bytes_to_read);
189     btstack_uart->receive_block(&hci_packet[read_pos], bytes_to_read);
190 }
191 
192 static void hci_transport_h4_block_read(void){
193 
194     read_pos += bytes_to_read;
195 
196     switch (h4_state) {
197         case H4_W4_PACKET_TYPE:
198             switch (hci_packet[0]){
199                 case HCI_EVENT_PACKET:
200                     bytes_to_read = HCI_EVENT_HEADER_SIZE;
201                     h4_state = H4_W4_EVENT_HEADER;
202                     break;
203                 case HCI_ACL_DATA_PACKET:
204                     bytes_to_read = HCI_ACL_HEADER_SIZE;
205                     h4_state = H4_W4_ACL_HEADER;
206                     break;
207                 case HCI_SCO_DATA_PACKET:
208                     bytes_to_read = HCI_SCO_HEADER_SIZE;
209                     h4_state = H4_W4_SCO_HEADER;
210                     break;
211 #ifdef ENABLE_EHCILL
212                 case EHCILL_GO_TO_SLEEP_IND:
213                 case EHCILL_GO_TO_SLEEP_ACK:
214                 case EHCILL_WAKE_UP_IND:
215                 case EHCILL_WAKE_UP_ACK:
216                     hci_transport_h4_ehcill_handle_command(hci_packet[0]);
217                     hci_transport_h4_reset_statemachine();
218                     break;
219 #endif
220                 default:
221                     log_error("hci_transport_h4: invalid packet type 0x%02x", hci_packet[0]);
222                     hci_transport_h4_reset_statemachine();
223                     break;
224             }
225             break;
226 
227         case H4_W4_EVENT_HEADER:
228             bytes_to_read = hci_packet[2];
229             // check Event length
230             if (bytes_to_read > (HCI_INCOMING_PACKET_BUFFER_SIZE - HCI_EVENT_HEADER_SIZE)){
231                 log_error("hci_transport_h4: invalid Event len %d - only space for %u", bytes_to_read, HCI_INCOMING_PACKET_BUFFER_SIZE - HCI_EVENT_HEADER_SIZE);
232                 hci_transport_h4_reset_statemachine();
233                 break;
234             }
235             h4_state = H4_W4_PAYLOAD;
236             break;
237 
238         case H4_W4_ACL_HEADER:
239             bytes_to_read = little_endian_read_16( hci_packet, 3);
240             // check ACL length
241             if (bytes_to_read > (HCI_INCOMING_PACKET_BUFFER_SIZE - HCI_ACL_HEADER_SIZE)){
242                 log_error("hci_transport_h4: invalid ACL payload len %d - only space for %u", bytes_to_read, HCI_INCOMING_PACKET_BUFFER_SIZE - HCI_ACL_HEADER_SIZE);
243                 hci_transport_h4_reset_statemachine();
244                 break;
245             }
246             h4_state = H4_W4_PAYLOAD;
247             break;
248 
249         case H4_W4_SCO_HEADER:
250             bytes_to_read = hci_packet[3];
251             // check SCO length
252             if (bytes_to_read > (HCI_INCOMING_PACKET_BUFFER_SIZE - HCI_SCO_HEADER_SIZE)){
253                 log_error("hci_transport_h4: invalid SCO payload len %d - only space for %u", bytes_to_read, HCI_INCOMING_PACKET_BUFFER_SIZE - HCI_SCO_HEADER_SIZE);
254                 hci_transport_h4_reset_statemachine();
255                 break;
256             }
257             h4_state = H4_W4_PAYLOAD;
258             break;
259 
260         case H4_W4_PAYLOAD:
261 #ifdef ENABLE_BAUDRATE_CHANGE_FLOWCONTROL_BUG_WORKAROUND
262             if (baudrate_change_workaround_state == BAUDRATE_CHANGE_WORKAROUND_IDLE
263             && memcmp(hci_packet, local_version_event_prefix, sizeof(local_version_event_prefix)) == 0){
264 #ifdef ENABLE_CC256X_BAUDRATE_CHANGE_FLOWCONTROL_BUG_WORKAROUND
265                 if (little_endian_read_16(hci_packet, 11) == BLUETOOTH_COMPANY_ID_TEXAS_INSTRUMENTS_INC){
266                     // detect TI CC256x controller based on manufacturer
267                     log_info("Detected CC256x controller");
268                     baudrate_change_workaround_state = BAUDRATE_CHANGE_WORKAROUND_CHIPSET_DETECTED;
269                 } else {
270                     // work around not needed
271                     log_info("Bluetooth controller not by TI");
272                     baudrate_change_workaround_state = BAUDRATE_CHANGE_WORKAROUND_DONE;
273                 }
274 #endif
275 #ifdef ENABLE_CYPRESS_BAUDRATE_CHANGE_FLOWCONTROL_BUG_WORKAROUND
276                 if (little_endian_read_16(hci_packet, 11) == BLUETOOTH_COMPANY_ID_CYPRESS_SEMICONDUCTOR){
277                     // detect Cypress controller based on manufacturer
278                     log_info("Detected Cypress controller");
279                     baudrate_change_workaround_state = BAUDRATE_CHANGE_WORKAROUND_CHIPSET_DETECTED;
280                 } else {
281                     // work around not needed
282                     log_info("Bluetooth controller not by Cypress");
283                     baudrate_change_workaround_state = BAUDRATE_CHANGE_WORKAROUND_DONE;
284                 }
285 #endif
286             }
287 #endif
288             packet_handler(hci_packet[0], &hci_packet[1], read_pos-1);
289             hci_transport_h4_reset_statemachine();
290             break;
291         default:
292             break;
293     }
294 
295 #ifdef ENABLE_BAUDRATE_CHANGE_FLOWCONTROL_BUG_WORKAROUND
296     if (baudrate_change_workaround_state == BAUDRATE_CHANGE_WORKAROUND_BAUDRATE_COMMAND_SENT){
297         baudrate_change_workaround_state = BAUDRATE_CHANGE_WORKAROUND_IDLE;
298         // avoid flowcontrol problem by reading expected hci command complete event of 7 bytes in a single block read
299         h4_state = H4_W4_PAYLOAD;
300         bytes_to_read = 7;
301     }
302 #endif
303 
304     hci_transport_h4_trigger_next_read();
305 }
306 
307 static void hci_transport_h4_block_sent(void){
308     switch (tx_state){
309         case TX_W4_PACKET_SENT:
310             // packet fully sent, reset state
311 #ifdef ENABLE_EHCILL
312             ehcill_tx_len = 0;
313 #endif
314             tx_state = TX_IDLE;
315 
316 #ifdef ENABLE_EHCILL
317             // notify eHCILL engine
318             hci_transport_h4_ehcill_handle_packet_sent();
319 #endif
320             // notify upper stack that it can send again
321             packet_handler(HCI_EVENT_PACKET, &packet_sent_event[0], sizeof(packet_sent_event));
322             break;
323 
324 #ifdef ENABLE_EHCILL
325         case TX_W4_EHCILL_SENT:
326         case TX_W4_WAKEUP:
327             hci_transport_h4_ehcill_handle_ehcill_command_sent();
328             break;
329 #endif
330 
331         default:
332             break;
333     }
334 }
335 
336 static int hci_transport_h4_can_send_now(uint8_t packet_type){
337     return tx_state == TX_IDLE;
338 }
339 
340 static int hci_transport_h4_send_packet(uint8_t packet_type, uint8_t * packet, int size){
341 
342     // store packet type before actual data and increase size
343     size++;
344     packet--;
345     *packet = packet_type;
346 
347 #ifdef ENABLE_BAUDRATE_CHANGE_FLOWCONTROL_BUG_WORKAROUND
348     if ((baudrate_change_workaround_state == BAUDRATE_CHANGE_WORKAROUND_CHIPSET_DETECTED)
349     && (memcmp(packet, baud_rate_command_prefix, sizeof(baud_rate_command_prefix)) == 0)) {
350         log_info("Baud rate command detected, expect command complete event next");
351         baudrate_change_workaround_state = BAUDRATE_CHANGE_WORKAROUND_BAUDRATE_COMMAND_SENT;
352     }
353 #endif
354 
355 #ifdef ENABLE_EHCILL
356     // store request for later
357     ehcill_tx_len   = size;
358     ehcill_tx_data  = packet;
359     switch (ehcill_state){
360         case EHCILL_STATE_SLEEP:
361             hci_transport_h4_ehcill_trigger_wakeup();
362             return 0;
363         case EHCILL_STATE_W2_SEND_SLEEP_ACK:
364             log_info("eHILL: send next packet, state EHCILL_STATE_W2_SEND_SLEEP_ACK");
365             return 0;
366         default:
367             break;
368     }
369 #endif
370 
371     // start sending
372     tx_state = TX_W4_PACKET_SENT;
373     btstack_uart->send_block(packet, size);
374     return 0;
375 }
376 
377 static void hci_transport_h4_init(const void * transport_config){
378     // check for hci_transport_config_uart_t
379     if (!transport_config) {
380         log_error("hci_transport_h4: no config!");
381         return;
382     }
383     if (((hci_transport_config_t*)transport_config)->type != HCI_TRANSPORT_CONFIG_UART) {
384         log_error("hci_transport_h4: config not of type != HCI_TRANSPORT_CONFIG_UART!");
385         return;
386     }
387 
388     // extract UART config from transport config
389     hci_transport_config_uart_t * hci_transport_config_uart = (hci_transport_config_uart_t*) transport_config;
390     uart_config.baudrate    = hci_transport_config_uart->baudrate_init;
391     uart_config.flowcontrol = hci_transport_config_uart->flowcontrol;
392     uart_config.device_name = hci_transport_config_uart->device_name;
393 
394     // set state to off
395     tx_state = TX_OFF;
396     h4_state = H4_OFF;
397 
398     // setup UART driver
399     btstack_uart->init(&uart_config);
400     btstack_uart->set_block_received(&hci_transport_h4_block_read);
401     btstack_uart->set_block_sent(&hci_transport_h4_block_sent);
402 }
403 
404 static int hci_transport_h4_open(void){
405     // open uart driver
406     int res = btstack_uart->open();
407     if (res){
408         return res;
409     }
410 
411     // init rx + tx state machines
412     hci_transport_h4_reset_statemachine();
413     hci_transport_h4_trigger_next_read();
414     tx_state = TX_IDLE;
415 
416 #ifdef ENABLE_EHCILL
417     hci_transport_h4_ehcill_open();
418 #endif
419     return 0;
420 }
421 
422 static int hci_transport_h4_close(void){
423     // set state to off
424     tx_state = TX_OFF;
425     h4_state = H4_OFF;
426 
427     // close uart driver
428     return btstack_uart->close();
429 }
430 
431 static void hci_transport_h4_register_packet_handler(void (*handler)(uint8_t packet_type, uint8_t *packet, uint16_t size)){
432     packet_handler = handler;
433 }
434 
435 static void dummy_handler(uint8_t packet_type, uint8_t *packet, uint16_t size){
436 }
437 
438 //
439 // --- main part of eHCILL implementation ---
440 //
441 
442 #ifdef ENABLE_EHCILL
443 
444 static void hci_transport_h4_ehcill_emit_sleep_state(int sleep_active){
445     static int last_state = 0;
446     if (sleep_active == last_state) return;
447     last_state = sleep_active;
448 
449     log_info("hci_transport_h4_ehcill_emit_sleep_state: %u", sleep_active);
450     uint8_t event[3];
451     event[0] = HCI_EVENT_TRANSPORT_SLEEP_MODE;
452     event[1] = sizeof(event) - 2;
453     event[2] = sleep_active;
454     packet_handler(HCI_EVENT_PACKET, &event[0], sizeof(event));
455 }
456 
457 static void hci_transport_h4_ehcill_wakeup_handler(void){
458 #ifdef ENABLE_LOG_EHCILL
459     log_info("eHCILL: UART wakeup received");
460 #endif
461     hci_transport_h4_ehcill_handle_command(EHCILL_WAKEUP_SIGNAL);
462 }
463 
464 static void hci_transport_h4_ehcill_open(void){
465     hci_transport_h4_ehcill_reset_statemachine();
466 
467     // find best sleep mode to use: wake on CTS, wake on RX, none
468     btstack_uart_sleep_mode = BTSTACK_UART_SLEEP_OFF;
469     int supported_sleep_modes = 0;
470     if (btstack_uart->get_supported_sleep_modes){
471         supported_sleep_modes = btstack_uart->get_supported_sleep_modes();
472     }
473     if (supported_sleep_modes & BTSTACK_UART_SLEEP_MASK_RTS_HIGH_WAKE_ON_CTS_PULSE){
474         log_info("eHCILL: using wake on CTS");
475         btstack_uart_sleep_mode = BTSTACK_UART_SLEEP_RTS_HIGH_WAKE_ON_CTS_PULSE;
476     } else if (supported_sleep_modes & BTSTACK_UART_SLEEP_MASK_RTS_LOW_WAKE_ON_RX_EDGE){
477         log_info("eHCILL: using wake on RX");
478         btstack_uart_sleep_mode = BTSTACK_UART_SLEEP_RTS_LOW_WAKE_ON_RX_EDGE;
479     } else {
480         log_info("eHCILL: UART driver does not provide compatible sleep mode");
481     }
482     if (btstack_uart->set_wakeup_handler){
483         btstack_uart->set_wakeup_handler(&hci_transport_h4_ehcill_wakeup_handler);
484     }
485 }
486 
487 static void hci_transport_h4_echill_send_wakeup_ind(void){
488 #ifdef ENABLE_LOG_EHCILL
489     log_info("eHCILL: send WAKEUP_IND");
490 #endif
491     // update state
492     tx_state     = TX_W4_WAKEUP;
493     ehcill_state = EHCILL_STATE_W4_WAKEUP_IND_OR_ACK;
494     ehcill_command_to_send = EHCILL_WAKE_UP_IND;
495     btstack_uart->send_block(&ehcill_command_to_send, 1);
496 }
497 
498 static int hci_transport_h4_ehcill_outgoing_packet_ready(void){
499     return ehcill_tx_len != 0;
500 }
501 
502 static void hci_transport_h4_ehcill_reset_statemachine(void){
503     ehcill_state = EHCILL_STATE_AWAKE;
504 }
505 
506 static void hci_transport_h4_ehcill_send_ehcill_command(void){
507 #ifdef ENABLE_LOG_EHCILL
508     log_info("eHCILL: send command %02x", ehcill_command_to_send);
509 #endif
510     tx_state = TX_W4_EHCILL_SENT;
511     if (ehcill_command_to_send == EHCILL_GO_TO_SLEEP_ACK){
512         ehcill_state = EHCILL_STATE_SLEEP;
513     }
514     btstack_uart->send_block(&ehcill_command_to_send, 1);
515 }
516 
517 static void hci_transport_h4_ehcill_sleep_ack_timer_handler(btstack_timer_source_t * timer){
518 	UNUSED(timer);
519 #ifdef ENABLE_LOG_EHCILL
520     log_info("eHCILL: timer triggered");
521 #endif
522     hci_transport_h4_ehcill_send_ehcill_command();
523 }
524 
525 static void hci_transport_h4_ehcill_sleep_ack_timer_setup(void){
526     // setup timer
527 #ifdef ENABLE_LOG_EHCILL
528     log_info("eHCILL: set timer for sending command %02x", ehcill_command_to_send);
529 #endif
530     btstack_run_loop_set_timer_handler(&ehcill_sleep_ack_timer, &hci_transport_h4_ehcill_sleep_ack_timer_handler);
531     btstack_run_loop_set_timer(&ehcill_sleep_ack_timer, 50);
532     btstack_run_loop_add_timer(&ehcill_sleep_ack_timer);
533 }
534 
535 static void hci_transport_h4_ehcill_trigger_wakeup(void){
536     switch (tx_state){
537         case TX_W2_EHCILL_SEND:
538         case TX_W4_EHCILL_SENT:
539             // wake up / sleep ack in progress, nothing to do now
540             return;
541         case TX_IDLE:
542         default:
543             // all clear, prepare for wakeup
544             break;
545     }
546     // UART needed again
547     hci_transport_h4_ehcill_emit_sleep_state(0);
548     if (btstack_uart_sleep_mode){
549         btstack_uart->set_sleep(BTSTACK_UART_SLEEP_OFF);
550     }
551     hci_transport_h4_echill_send_wakeup_ind();
552 }
553 
554 static void hci_transport_h4_ehcill_schedule_ehcill_command(uint8_t command){
555 #ifdef ENABLE_LOG_EHCILL
556     log_info("eHCILL: schedule eHCILL command %02x", command);
557 #endif
558     ehcill_command_to_send = command;
559     switch (tx_state){
560         case TX_IDLE:
561             if (ehcill_command_to_send == EHCILL_WAKE_UP_ACK){
562                 // send right away
563                 hci_transport_h4_ehcill_send_ehcill_command();
564             } else {
565                 // change state so BTstack cannot send and setup timer
566                 tx_state = TX_W2_EHCILL_SEND;
567                 hci_transport_h4_ehcill_sleep_ack_timer_setup();
568             }
569             break;
570         default:
571             break;
572     }
573 }
574 
575 static void hci_transport_h4_ehcill_handle_command(uint8_t action){
576     // log_info("hci_transport_h4_ehcill_handle: %x, state %u, defer_rx %u", action, ehcill_state, ehcill_defer_rx_size);
577     switch(ehcill_state){
578         case EHCILL_STATE_AWAKE:
579             switch(action){
580                 case EHCILL_GO_TO_SLEEP_IND:
581                     ehcill_state = EHCILL_STATE_W2_SEND_SLEEP_ACK;
582 #ifdef ENABLE_LOG_EHCILL
583                     log_info("eHCILL: Received GO_TO_SLEEP_IND RX");
584 #endif
585                     hci_transport_h4_ehcill_schedule_ehcill_command(EHCILL_GO_TO_SLEEP_ACK);
586                     break;
587                 default:
588                     break;
589             }
590             break;
591 
592         case EHCILL_STATE_W2_SEND_SLEEP_ACK:
593             switch(action){
594                 case EHCILL_WAKE_UP_IND:
595                     ehcill_state = EHCILL_STATE_AWAKE;
596                     hci_transport_h4_ehcill_emit_sleep_state(0);
597                     if (btstack_uart_sleep_mode){
598                         btstack_uart->set_sleep(BTSTACK_UART_SLEEP_OFF);
599                     }
600 #ifdef ENABLE_LOG_EHCILL
601                     log_info("eHCILL: Received WAKE_UP_IND RX");
602 #endif
603                     hci_transport_h4_ehcill_schedule_ehcill_command(EHCILL_WAKE_UP_ACK);
604                     break;
605 
606                 default:
607                     break;
608             }
609             break;
610 
611         case EHCILL_STATE_SLEEP:
612             switch(action){
613                 case EHCILL_WAKEUP_SIGNAL:
614                     hci_transport_h4_ehcill_emit_sleep_state(0);
615                     if (btstack_uart_sleep_mode){
616                         btstack_uart->set_sleep(BTSTACK_UART_SLEEP_OFF);
617                     }
618                     break;
619                 case EHCILL_WAKE_UP_IND:
620                     ehcill_state = EHCILL_STATE_AWAKE;
621                     hci_transport_h4_ehcill_emit_sleep_state(0);
622                     if (btstack_uart_sleep_mode){
623                         btstack_uart->set_sleep(BTSTACK_UART_SLEEP_OFF);
624                     }
625 #ifdef ENABLE_LOG_EHCILL
626                     log_info("eHCILL: Received WAKE_UP_IND RX");
627 #endif
628                     hci_transport_h4_ehcill_schedule_ehcill_command(EHCILL_WAKE_UP_ACK);
629                     break;
630 
631                 default:
632                     break;
633             }
634             break;
635 
636         case EHCILL_STATE_W4_WAKEUP_IND_OR_ACK:
637             switch(action){
638                 case EHCILL_WAKE_UP_IND:
639                 case EHCILL_WAKE_UP_ACK:
640 #ifdef ENABLE_LOG_EHCILL
641                     log_info("eHCILL: Received WAKE_UP (%02x)", action);
642 #endif
643                     tx_state = TX_W4_PACKET_SENT;
644                     ehcill_state = EHCILL_STATE_AWAKE;
645                     btstack_uart->send_block(ehcill_tx_data, ehcill_tx_len);
646                     break;
647                 default:
648                     break;
649             }
650             break;
651     }
652 }
653 
654 static void hci_transport_h4_ehcill_handle_packet_sent(void){
655 #ifdef ENABLE_LOG_EHCILL
656         log_info("eHCILL: handle packet sent, command to send %02x", ehcill_command_to_send);
657 #endif
658     // now, send pending ehcill command if neccessary
659     switch (ehcill_command_to_send){
660         case EHCILL_GO_TO_SLEEP_ACK:
661             hci_transport_h4_ehcill_sleep_ack_timer_setup();
662             break;
663         case EHCILL_WAKE_UP_IND:
664             hci_transport_h4_ehcill_send_ehcill_command();
665             break;
666         default:
667             break;
668     }
669 }
670 
671 static void hci_transport_h4_ehcill_handle_ehcill_command_sent(void){
672     tx_state = TX_IDLE;
673     int command = ehcill_command_to_send;
674     ehcill_command_to_send = 0;
675 
676 #ifdef ENABLE_LOG_EHCILL
677         log_info("eHCILL: handle eHCILL sent, command was %02x", command);
678 #endif
679 
680     if (command == EHCILL_GO_TO_SLEEP_ACK) {
681 #ifdef ENABLE_LOG_EHCILL
682         log_info("eHCILL: GO_TO_SLEEP_ACK sent, enter sleep mode");
683 #endif
684         // UART not needed after EHCILL_GO_TO_SLEEP_ACK was sent
685         if (btstack_uart_sleep_mode != BTSTACK_UART_SLEEP_OFF){
686             btstack_uart->set_sleep(btstack_uart_sleep_mode);
687         }
688         hci_transport_h4_ehcill_emit_sleep_state(1);
689     }
690     // already packet ready? then start wakeup
691     if (hci_transport_h4_ehcill_outgoing_packet_ready()){
692         hci_transport_h4_ehcill_emit_sleep_state(0);
693         if (btstack_uart_sleep_mode != BTSTACK_UART_SLEEP_OFF){
694             btstack_uart->set_sleep(BTSTACK_UART_SLEEP_OFF);
695         }
696         if (command != EHCILL_WAKE_UP_IND){
697             hci_transport_h4_echill_send_wakeup_ind();
698         }
699     }
700 }
701 
702 #endif
703 // --- end of eHCILL implementation ---------
704 
705 static const hci_transport_t hci_transport_h4 = {
706     /* const char * name; */                                        "H4",
707     /* void   (*init) (const void *transport_config); */            &hci_transport_h4_init,
708     /* int    (*open)(void); */                                     &hci_transport_h4_open,
709     /* int    (*close)(void); */                                    &hci_transport_h4_close,
710     /* void   (*register_packet_handler)(void (*handler)(...); */   &hci_transport_h4_register_packet_handler,
711     /* int    (*can_send_packet_now)(uint8_t packet_type); */       &hci_transport_h4_can_send_now,
712     /* int    (*send_packet)(...); */                               &hci_transport_h4_send_packet,
713     /* int    (*set_baudrate)(uint32_t baudrate); */                &hci_transport_h4_set_baudrate,
714     /* void   (*reset_link)(void); */                               NULL,
715     /* void   (*set_sco_config)(uint16_t voice_setting, int num_connections); */ NULL,
716 };
717 
718 // configure and return h4 singleton
719 const hci_transport_t * hci_transport_h4_instance(const btstack_uart_block_t * uart_driver) {
720     btstack_uart = uart_driver;
721     return &hci_transport_h4;
722 }
723