xref: /btstack/src/hci_transport_h4.c (revision e80b814d7d95d222266699cef2779523a2eac7d9)
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 
292         case H4_OFF:
293             bytes_to_read = 0;
294             break;
295     }
296 
297 #ifdef ENABLE_BAUDRATE_CHANGE_FLOWCONTROL_BUG_WORKAROUND
298     if (baudrate_change_workaround_state == BAUDRATE_CHANGE_WORKAROUND_BAUDRATE_COMMAND_SENT){
299         baudrate_change_workaround_state = BAUDRATE_CHANGE_WORKAROUND_IDLE;
300         // avoid flowcontrol problem by reading expected hci command complete event of 7 bytes in a single block read
301         h4_state = H4_W4_PAYLOAD;
302         bytes_to_read = 7;
303     }
304 #endif
305 
306     if (h4_state != H4_OFF) {
307         hci_transport_h4_trigger_next_read();
308     }
309 }
310 
311 static void hci_transport_h4_block_sent(void){
312     switch (tx_state){
313         case TX_W4_PACKET_SENT:
314             // packet fully sent, reset state
315 #ifdef ENABLE_EHCILL
316             ehcill_tx_len = 0;
317 #endif
318             tx_state = TX_IDLE;
319 
320 #ifdef ENABLE_EHCILL
321             // notify eHCILL engine
322             hci_transport_h4_ehcill_handle_packet_sent();
323 #endif
324             // notify upper stack that it can send again
325             packet_handler(HCI_EVENT_PACKET, &packet_sent_event[0], sizeof(packet_sent_event));
326             break;
327 
328 #ifdef ENABLE_EHCILL
329         case TX_W4_EHCILL_SENT:
330         case TX_W4_WAKEUP:
331             hci_transport_h4_ehcill_handle_ehcill_command_sent();
332             break;
333 #endif
334 
335         default:
336             break;
337     }
338 }
339 
340 static int hci_transport_h4_can_send_now(uint8_t packet_type){
341     return tx_state == TX_IDLE;
342 }
343 
344 static int hci_transport_h4_send_packet(uint8_t packet_type, uint8_t * packet, int size){
345 
346     // store packet type before actual data and increase size
347     size++;
348     packet--;
349     *packet = packet_type;
350 
351 #ifdef ENABLE_BAUDRATE_CHANGE_FLOWCONTROL_BUG_WORKAROUND
352     if ((baudrate_change_workaround_state == BAUDRATE_CHANGE_WORKAROUND_CHIPSET_DETECTED)
353     && (memcmp(packet, baud_rate_command_prefix, sizeof(baud_rate_command_prefix)) == 0)) {
354         log_info("Baud rate command detected, expect command complete event next");
355         baudrate_change_workaround_state = BAUDRATE_CHANGE_WORKAROUND_BAUDRATE_COMMAND_SENT;
356     }
357 #endif
358 
359 #ifdef ENABLE_EHCILL
360     // store request for later
361     ehcill_tx_len   = size;
362     ehcill_tx_data  = packet;
363     switch (ehcill_state){
364         case EHCILL_STATE_SLEEP:
365             hci_transport_h4_ehcill_trigger_wakeup();
366             return 0;
367         case EHCILL_STATE_W2_SEND_SLEEP_ACK:
368             log_info("eHILL: send next packet, state EHCILL_STATE_W2_SEND_SLEEP_ACK");
369             return 0;
370         default:
371             break;
372     }
373 #endif
374 
375     // start sending
376     tx_state = TX_W4_PACKET_SENT;
377     btstack_uart->send_block(packet, size);
378     return 0;
379 }
380 
381 static void hci_transport_h4_init(const void * transport_config){
382     // check for hci_transport_config_uart_t
383     if (!transport_config) {
384         log_error("hci_transport_h4: no config!");
385         return;
386     }
387     if (((hci_transport_config_t*)transport_config)->type != HCI_TRANSPORT_CONFIG_UART) {
388         log_error("hci_transport_h4: config not of type != HCI_TRANSPORT_CONFIG_UART!");
389         return;
390     }
391 
392     // extract UART config from transport config
393     hci_transport_config_uart_t * hci_transport_config_uart = (hci_transport_config_uart_t*) transport_config;
394     uart_config.baudrate    = hci_transport_config_uart->baudrate_init;
395     uart_config.flowcontrol = hci_transport_config_uart->flowcontrol;
396     uart_config.device_name = hci_transport_config_uart->device_name;
397 
398     // set state to off
399     tx_state = TX_OFF;
400     h4_state = H4_OFF;
401 
402     // setup UART driver
403     btstack_uart->init(&uart_config);
404     btstack_uart->set_block_received(&hci_transport_h4_block_read);
405     btstack_uart->set_block_sent(&hci_transport_h4_block_sent);
406 }
407 
408 static int hci_transport_h4_open(void){
409     // open uart driver
410     int res = btstack_uart->open();
411     if (res){
412         return res;
413     }
414 
415     // init rx + tx state machines
416     hci_transport_h4_reset_statemachine();
417     hci_transport_h4_trigger_next_read();
418     tx_state = TX_IDLE;
419 
420 #ifdef ENABLE_EHCILL
421     hci_transport_h4_ehcill_open();
422 #endif
423     return 0;
424 }
425 
426 static int hci_transport_h4_close(void){
427     // set state to off
428     tx_state = TX_OFF;
429     h4_state = H4_OFF;
430 
431     // close uart driver
432     return btstack_uart->close();
433 }
434 
435 static void hci_transport_h4_register_packet_handler(void (*handler)(uint8_t packet_type, uint8_t *packet, uint16_t size)){
436     packet_handler = handler;
437 }
438 
439 static void dummy_handler(uint8_t packet_type, uint8_t *packet, uint16_t size){
440 }
441 
442 //
443 // --- main part of eHCILL implementation ---
444 //
445 
446 #ifdef ENABLE_EHCILL
447 
448 static void hci_transport_h4_ehcill_emit_sleep_state(int sleep_active){
449     static int last_state = 0;
450     if (sleep_active == last_state) return;
451     last_state = sleep_active;
452 
453     log_info("hci_transport_h4_ehcill_emit_sleep_state: %u", sleep_active);
454     uint8_t event[3];
455     event[0] = HCI_EVENT_TRANSPORT_SLEEP_MODE;
456     event[1] = sizeof(event) - 2;
457     event[2] = sleep_active;
458     packet_handler(HCI_EVENT_PACKET, &event[0], sizeof(event));
459 }
460 
461 static void hci_transport_h4_ehcill_wakeup_handler(void){
462 #ifdef ENABLE_LOG_EHCILL
463     log_info("eHCILL: UART wakeup received");
464 #endif
465     hci_transport_h4_ehcill_handle_command(EHCILL_WAKEUP_SIGNAL);
466 }
467 
468 static void hci_transport_h4_ehcill_open(void){
469     hci_transport_h4_ehcill_reset_statemachine();
470 
471     // find best sleep mode to use: wake on CTS, wake on RX, none
472     btstack_uart_sleep_mode = BTSTACK_UART_SLEEP_OFF;
473     int supported_sleep_modes = 0;
474     if (btstack_uart->get_supported_sleep_modes){
475         supported_sleep_modes = btstack_uart->get_supported_sleep_modes();
476     }
477     if (supported_sleep_modes & BTSTACK_UART_SLEEP_MASK_RTS_HIGH_WAKE_ON_CTS_PULSE){
478         log_info("eHCILL: using wake on CTS");
479         btstack_uart_sleep_mode = BTSTACK_UART_SLEEP_RTS_HIGH_WAKE_ON_CTS_PULSE;
480     } else if (supported_sleep_modes & BTSTACK_UART_SLEEP_MASK_RTS_LOW_WAKE_ON_RX_EDGE){
481         log_info("eHCILL: using wake on RX");
482         btstack_uart_sleep_mode = BTSTACK_UART_SLEEP_RTS_LOW_WAKE_ON_RX_EDGE;
483     } else {
484         log_info("eHCILL: UART driver does not provide compatible sleep mode");
485     }
486     if (btstack_uart->set_wakeup_handler){
487         btstack_uart->set_wakeup_handler(&hci_transport_h4_ehcill_wakeup_handler);
488     }
489 }
490 
491 static void hci_transport_h4_echill_send_wakeup_ind(void){
492 #ifdef ENABLE_LOG_EHCILL
493     log_info("eHCILL: send WAKEUP_IND");
494 #endif
495     // update state
496     tx_state     = TX_W4_WAKEUP;
497     ehcill_state = EHCILL_STATE_W4_WAKEUP_IND_OR_ACK;
498     ehcill_command_to_send = EHCILL_WAKE_UP_IND;
499     btstack_uart->send_block(&ehcill_command_to_send, 1);
500 }
501 
502 static int hci_transport_h4_ehcill_outgoing_packet_ready(void){
503     return ehcill_tx_len != 0;
504 }
505 
506 static void hci_transport_h4_ehcill_reset_statemachine(void){
507     ehcill_state = EHCILL_STATE_AWAKE;
508 }
509 
510 static void hci_transport_h4_ehcill_send_ehcill_command(void){
511 #ifdef ENABLE_LOG_EHCILL
512     log_info("eHCILL: send command %02x", ehcill_command_to_send);
513 #endif
514     tx_state = TX_W4_EHCILL_SENT;
515     if (ehcill_command_to_send == EHCILL_GO_TO_SLEEP_ACK){
516         ehcill_state = EHCILL_STATE_SLEEP;
517     }
518     btstack_uart->send_block(&ehcill_command_to_send, 1);
519 }
520 
521 static void hci_transport_h4_ehcill_sleep_ack_timer_handler(btstack_timer_source_t * timer){
522 	UNUSED(timer);
523 #ifdef ENABLE_LOG_EHCILL
524     log_info("eHCILL: timer triggered");
525 #endif
526     hci_transport_h4_ehcill_send_ehcill_command();
527 }
528 
529 static void hci_transport_h4_ehcill_sleep_ack_timer_setup(void){
530     // setup timer
531 #ifdef ENABLE_LOG_EHCILL
532     log_info("eHCILL: set timer for sending command %02x", ehcill_command_to_send);
533 #endif
534     btstack_run_loop_set_timer_handler(&ehcill_sleep_ack_timer, &hci_transport_h4_ehcill_sleep_ack_timer_handler);
535     btstack_run_loop_set_timer(&ehcill_sleep_ack_timer, 50);
536     btstack_run_loop_add_timer(&ehcill_sleep_ack_timer);
537 }
538 
539 static void hci_transport_h4_ehcill_trigger_wakeup(void){
540     switch (tx_state){
541         case TX_W2_EHCILL_SEND:
542         case TX_W4_EHCILL_SENT:
543             // wake up / sleep ack in progress, nothing to do now
544             return;
545         case TX_IDLE:
546         default:
547             // all clear, prepare for wakeup
548             break;
549     }
550     // UART needed again
551     hci_transport_h4_ehcill_emit_sleep_state(0);
552     if (btstack_uart_sleep_mode){
553         btstack_uart->set_sleep(BTSTACK_UART_SLEEP_OFF);
554     }
555     hci_transport_h4_echill_send_wakeup_ind();
556 }
557 
558 static void hci_transport_h4_ehcill_schedule_ehcill_command(uint8_t command){
559 #ifdef ENABLE_LOG_EHCILL
560     log_info("eHCILL: schedule eHCILL command %02x", command);
561 #endif
562     ehcill_command_to_send = command;
563     switch (tx_state){
564         case TX_IDLE:
565             if (ehcill_command_to_send == EHCILL_WAKE_UP_ACK){
566                 // send right away
567                 hci_transport_h4_ehcill_send_ehcill_command();
568             } else {
569                 // change state so BTstack cannot send and setup timer
570                 tx_state = TX_W2_EHCILL_SEND;
571                 hci_transport_h4_ehcill_sleep_ack_timer_setup();
572             }
573             break;
574         default:
575             break;
576     }
577 }
578 
579 static void hci_transport_h4_ehcill_handle_command(uint8_t action){
580     // log_info("hci_transport_h4_ehcill_handle: %x, state %u, defer_rx %u", action, ehcill_state, ehcill_defer_rx_size);
581     switch(ehcill_state){
582         case EHCILL_STATE_AWAKE:
583             switch(action){
584                 case EHCILL_GO_TO_SLEEP_IND:
585                     ehcill_state = EHCILL_STATE_W2_SEND_SLEEP_ACK;
586 #ifdef ENABLE_LOG_EHCILL
587                     log_info("eHCILL: Received GO_TO_SLEEP_IND RX");
588 #endif
589                     hci_transport_h4_ehcill_schedule_ehcill_command(EHCILL_GO_TO_SLEEP_ACK);
590                     break;
591                 default:
592                     break;
593             }
594             break;
595 
596         case EHCILL_STATE_W2_SEND_SLEEP_ACK:
597             switch(action){
598                 case EHCILL_WAKE_UP_IND:
599                     ehcill_state = EHCILL_STATE_AWAKE;
600                     hci_transport_h4_ehcill_emit_sleep_state(0);
601                     if (btstack_uart_sleep_mode){
602                         btstack_uart->set_sleep(BTSTACK_UART_SLEEP_OFF);
603                     }
604 #ifdef ENABLE_LOG_EHCILL
605                     log_info("eHCILL: Received WAKE_UP_IND RX");
606 #endif
607                     hci_transport_h4_ehcill_schedule_ehcill_command(EHCILL_WAKE_UP_ACK);
608                     break;
609 
610                 default:
611                     break;
612             }
613             break;
614 
615         case EHCILL_STATE_SLEEP:
616             switch(action){
617                 case EHCILL_WAKEUP_SIGNAL:
618                     hci_transport_h4_ehcill_emit_sleep_state(0);
619                     if (btstack_uart_sleep_mode){
620                         btstack_uart->set_sleep(BTSTACK_UART_SLEEP_OFF);
621                     }
622                     break;
623                 case EHCILL_WAKE_UP_IND:
624                     ehcill_state = EHCILL_STATE_AWAKE;
625                     hci_transport_h4_ehcill_emit_sleep_state(0);
626                     if (btstack_uart_sleep_mode){
627                         btstack_uart->set_sleep(BTSTACK_UART_SLEEP_OFF);
628                     }
629 #ifdef ENABLE_LOG_EHCILL
630                     log_info("eHCILL: Received WAKE_UP_IND RX");
631 #endif
632                     hci_transport_h4_ehcill_schedule_ehcill_command(EHCILL_WAKE_UP_ACK);
633                     break;
634 
635                 default:
636                     break;
637             }
638             break;
639 
640         case EHCILL_STATE_W4_WAKEUP_IND_OR_ACK:
641             switch(action){
642                 case EHCILL_WAKE_UP_IND:
643                 case EHCILL_WAKE_UP_ACK:
644 #ifdef ENABLE_LOG_EHCILL
645                     log_info("eHCILL: Received WAKE_UP (%02x)", action);
646 #endif
647                     tx_state = TX_W4_PACKET_SENT;
648                     ehcill_state = EHCILL_STATE_AWAKE;
649                     btstack_uart->send_block(ehcill_tx_data, ehcill_tx_len);
650                     break;
651                 default:
652                     break;
653             }
654             break;
655     }
656 }
657 
658 static void hci_transport_h4_ehcill_handle_packet_sent(void){
659 #ifdef ENABLE_LOG_EHCILL
660         log_info("eHCILL: handle packet sent, command to send %02x", ehcill_command_to_send);
661 #endif
662     // now, send pending ehcill command if neccessary
663     switch (ehcill_command_to_send){
664         case EHCILL_GO_TO_SLEEP_ACK:
665             hci_transport_h4_ehcill_sleep_ack_timer_setup();
666             break;
667         case EHCILL_WAKE_UP_IND:
668             hci_transport_h4_ehcill_send_ehcill_command();
669             break;
670         default:
671             break;
672     }
673 }
674 
675 static void hci_transport_h4_ehcill_handle_ehcill_command_sent(void){
676     tx_state = TX_IDLE;
677     int command = ehcill_command_to_send;
678     ehcill_command_to_send = 0;
679 
680 #ifdef ENABLE_LOG_EHCILL
681         log_info("eHCILL: handle eHCILL sent, command was %02x", command);
682 #endif
683 
684     if (command == EHCILL_GO_TO_SLEEP_ACK) {
685 #ifdef ENABLE_LOG_EHCILL
686         log_info("eHCILL: GO_TO_SLEEP_ACK sent, enter sleep mode");
687 #endif
688         // UART not needed after EHCILL_GO_TO_SLEEP_ACK was sent
689         if (btstack_uart_sleep_mode != BTSTACK_UART_SLEEP_OFF){
690             btstack_uart->set_sleep(btstack_uart_sleep_mode);
691         }
692         hci_transport_h4_ehcill_emit_sleep_state(1);
693     }
694     // already packet ready? then start wakeup
695     if (hci_transport_h4_ehcill_outgoing_packet_ready()){
696         hci_transport_h4_ehcill_emit_sleep_state(0);
697         if (btstack_uart_sleep_mode != BTSTACK_UART_SLEEP_OFF){
698             btstack_uart->set_sleep(BTSTACK_UART_SLEEP_OFF);
699         }
700         if (command != EHCILL_WAKE_UP_IND){
701             hci_transport_h4_echill_send_wakeup_ind();
702         }
703     }
704 }
705 
706 #endif
707 // --- end of eHCILL implementation ---------
708 
709 static const hci_transport_t hci_transport_h4 = {
710     /* const char * name; */                                        "H4",
711     /* void   (*init) (const void *transport_config); */            &hci_transport_h4_init,
712     /* int    (*open)(void); */                                     &hci_transport_h4_open,
713     /* int    (*close)(void); */                                    &hci_transport_h4_close,
714     /* void   (*register_packet_handler)(void (*handler)(...); */   &hci_transport_h4_register_packet_handler,
715     /* int    (*can_send_packet_now)(uint8_t packet_type); */       &hci_transport_h4_can_send_now,
716     /* int    (*send_packet)(...); */                               &hci_transport_h4_send_packet,
717     /* int    (*set_baudrate)(uint32_t baudrate); */                &hci_transport_h4_set_baudrate,
718     /* void   (*reset_link)(void); */                               NULL,
719     /* void   (*set_sco_config)(uint16_t voice_setting, int num_connections); */ NULL,
720 };
721 
722 // configure and return h4 singleton
723 const hci_transport_t * hci_transport_h4_instance(const btstack_uart_block_t * uart_driver) {
724     btstack_uart = uart_driver;
725     return &hci_transport_h4;
726 }
727