xref: /btstack/src/hci_transport_h4.c (revision bb90a366cb0f6d8213832c136271abf96da44e99)
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 BLUEKITCHEN
24  * GMBH 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 
49 #include "btstack_config.h"
50 #include "hci_transport_h4.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 #include <inttypes.h>
59 
60 #define ENABLE_LOG_EHCILL
61 
62 #ifdef ENABLE_EHCILL
63 
64 // eHCILL commands
65 enum EHCILL_MESSAGES {
66 	EHCILL_GO_TO_SLEEP_IND = 0x030,
67 	EHCILL_GO_TO_SLEEP_ACK = 0x031,
68 	EHCILL_WAKE_UP_IND     = 0x032,
69 	EHCILL_WAKE_UP_ACK     = 0x033,
70 	EHCILL_WAKEUP_SIGNAL   = 0x034,
71 };
72 
73 static int  hci_transport_h4_ehcill_outgoing_packet_ready(void);
74 static void hci_transport_h4_echill_send_wakeup_ind(void);
75 static void hci_transport_h4_ehcill_handle_command(uint8_t action);
76 static void hci_transport_h4_ehcill_handle_ehcill_command_sent(void);
77 static void hci_transport_h4_ehcill_handle_packet_sent(void);
78 static void hci_transport_h4_ehcill_open(void);
79 static void hci_transport_h4_ehcill_reset_statemachine(void);
80 static void hci_transport_h4_ehcill_send_ehcill_command(void);
81 static void hci_transport_h4_ehcill_sleep_ack_timer_setup(void);
82 static void hci_transport_h4_ehcill_trigger_wakeup(void);
83 
84 typedef enum {
85     EHCILL_STATE_W2_SEND_SLEEP_ACK,
86     EHCILL_STATE_SLEEP,
87     EHCILL_STATE_W4_WAKEUP_IND_OR_ACK,
88     EHCILL_STATE_AWAKE
89 } EHCILL_STATE;
90 
91 // eHCILL state machine
92 static EHCILL_STATE ehcill_state;
93 static uint8_t      ehcill_command_to_send;
94 
95 static btstack_uart_sleep_mode_t btstack_uart_sleep_mode;
96 
97 // work around for eHCILL problem
98 static btstack_timer_source_t ehcill_sleep_ack_timer;
99 
100 #endif
101 
102 
103 // assert pre-buffer for packet type is available
104 #if !defined(HCI_OUTGOING_PRE_BUFFER_SIZE) || (HCI_OUTGOING_PRE_BUFFER_SIZE == 0)
105 #error HCI_OUTGOING_PRE_BUFFER_SIZE not defined. Please update hci.h
106 #endif
107 
108 static void dummy_handler(uint8_t packet_type, uint8_t *packet, uint16_t size);
109 
110 typedef enum {
111     H4_OFF,
112     H4_W4_PACKET_TYPE,
113     H4_W4_EVENT_HEADER,
114     H4_W4_ACL_HEADER,
115     H4_W4_SCO_HEADER,
116     H4_W4_ISO_HEADER,
117     H4_W4_PAYLOAD,
118 } H4_STATE;
119 
120 typedef enum {
121     TX_OFF,
122     TX_IDLE,
123     TX_W4_PACKET_SENT,
124 #ifdef ENABLE_EHCILL
125     TX_W4_WAKEUP,
126     TX_W2_EHCILL_SEND,
127     TX_W4_EHCILL_SENT,
128 #endif
129 } TX_STATE;
130 
131 // UART Driver + Config
132 static const btstack_uart_t * btstack_uart;
133 static btstack_uart_config_t hci_transport_h4_uart_config;
134 
135 // write state
136 static TX_STATE tx_state;
137 #ifdef ENABLE_EHCILL
138 static uint8_t * ehcill_tx_data;
139 static uint16_t  ehcill_tx_len;   // 0 == no outgoing packet
140 #endif
141 
142 static void (*hci_transport_h4_packet_handler)(uint8_t packet_type, uint8_t *packet, uint16_t size) = dummy_handler;
143 
144 // packet reader state machine
145 static  H4_STATE h4_state;
146 static uint16_t bytes_to_read;
147 static uint16_t read_pos;
148 
149 // incoming packet buffer
150 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)
151 static uint8_t * hci_packet = &hci_packet_with_pre_buffer[HCI_INCOMING_PRE_BUFFER_SIZE];
152 
153 // Baudrate change bugs in TI CC256x and CYW20704
154 #ifdef ENABLE_CC256X_BAUDRATE_CHANGE_FLOWCONTROL_BUG_WORKAROUND
155 #define ENABLE_BAUDRATE_CHANGE_FLOWCONTROL_BUG_WORKAROUND
156 static const uint8_t baud_rate_command_prefix[]   = { 0x01, 0x36, 0xff, 0x04};
157 #endif
158 
159 #ifdef ENABLE_CYPRESS_BAUDRATE_CHANGE_FLOWCONTROL_BUG_WORKAROUND
160 #ifdef ENABLE_BAUDRATE_CHANGE_FLOWCONTROL_BUG_WORKAROUND
161 #error "Please enable either ENABLE_CC256X_BAUDRATE_CHANGE_FLOWCONTROL_BUG_WORKAROUND or ENABLE_BAUDRATE_CHANGE_FLOWCONTROL_BUG_WORKAROUND"
162 #endif
163 #define ENABLE_BAUDRATE_CHANGE_FLOWCONTROL_BUG_WORKAROUND
164 static const uint8_t baud_rate_command_prefix[]   = { 0x01, 0x18, 0xfc, 0x06};
165 #endif
166 
167 #ifdef ENABLE_BAUDRATE_CHANGE_FLOWCONTROL_BUG_WORKAROUND
168 static const uint8_t local_version_event_prefix[] = { 0x04, 0x0e, 0x0c, 0x01, 0x01, 0x10};
169 static enum {
170     BAUDRATE_CHANGE_WORKAROUND_IDLE,
171     BAUDRATE_CHANGE_WORKAROUND_CHIPSET_DETECTED,
172     BAUDRATE_CHANGE_WORKAROUND_BAUDRATE_COMMAND_SENT,
173     BAUDRATE_CHANGE_WORKAROUND_DONE
174 } baudrate_change_workaround_state;
175 #endif
176 
177 static int hci_transport_h4_set_baudrate(uint32_t baudrate){
178     log_info("hci_transport_h4_set_baudrate %"PRIu32, baudrate);
179     return btstack_uart->set_baudrate(baudrate);
180 }
181 
182 static void hci_transport_h4_reset_statemachine(void){
183     h4_state = H4_W4_PACKET_TYPE;
184     read_pos = 0;
185     bytes_to_read = 1;
186 }
187 
188 static void hci_transport_h4_trigger_next_read(void){
189     // log_info("hci_transport_h4_trigger_next_read: %u bytes", bytes_to_read);
190     btstack_uart->receive_block(&hci_packet[read_pos], bytes_to_read);
191 }
192 
193 static void hci_transport_h4_packet_complete(void){
194 #ifdef ENABLE_BAUDRATE_CHANGE_FLOWCONTROL_BUG_WORKAROUND
195     if (baudrate_change_workaround_state == BAUDRATE_CHANGE_WORKAROUND_IDLE
196             && memcmp(hci_packet, local_version_event_prefix, sizeof(local_version_event_prefix)) == 0){
197 #ifdef ENABLE_CC256X_BAUDRATE_CHANGE_FLOWCONTROL_BUG_WORKAROUND
198                 if (little_endian_read_16(hci_packet, 11) == BLUETOOTH_COMPANY_ID_TEXAS_INSTRUMENTS_INC){
199                     // detect TI CC256x controller based on manufacturer
200                     log_info("Detected CC256x controller");
201                     baudrate_change_workaround_state = BAUDRATE_CHANGE_WORKAROUND_CHIPSET_DETECTED;
202                 } else {
203                     // work around not needed
204                     log_info("Bluetooth controller not by TI");
205                     baudrate_change_workaround_state = BAUDRATE_CHANGE_WORKAROUND_DONE;
206                 }
207 #endif
208 #ifdef ENABLE_CYPRESS_BAUDRATE_CHANGE_FLOWCONTROL_BUG_WORKAROUND
209                 if (little_endian_read_16(hci_packet, 11) == BLUETOOTH_COMPANY_ID_CYPRESS_SEMICONDUCTOR){
210                     // detect Cypress controller based on manufacturer
211                     log_info("Detected Cypress controller");
212                     baudrate_change_workaround_state = BAUDRATE_CHANGE_WORKAROUND_CHIPSET_DETECTED;
213                 } else {
214                     // work around not needed
215                     log_info("Bluetooth controller not by Cypress");
216                     baudrate_change_workaround_state = BAUDRATE_CHANGE_WORKAROUND_DONE;
217                 }
218 #endif
219             }
220 #endif
221     uint16_t packet_len = read_pos-1u;
222 
223     // reset state machine before delivering packet to stack as it might close the transport
224     hci_transport_h4_reset_statemachine();
225     hci_transport_h4_packet_handler(hci_packet[0], &hci_packet[1], packet_len);
226 }
227 
228 static void hci_transport_h4_block_read(void){
229 
230     read_pos += bytes_to_read;
231 
232     switch (h4_state) {
233         case H4_W4_PACKET_TYPE:
234             switch (hci_packet[0]){
235                 case HCI_EVENT_PACKET:
236                     bytes_to_read = HCI_EVENT_HEADER_SIZE;
237                     h4_state = H4_W4_EVENT_HEADER;
238                     break;
239                 case HCI_ACL_DATA_PACKET:
240                     bytes_to_read = HCI_ACL_HEADER_SIZE;
241                     h4_state = H4_W4_ACL_HEADER;
242                     break;
243                 case HCI_SCO_DATA_PACKET:
244                     bytes_to_read = HCI_SCO_HEADER_SIZE;
245                     h4_state = H4_W4_SCO_HEADER;
246                     break;
247                 case HCI_ISO_DATA_PACKET:
248                     bytes_to_read = HCI_ISO_HEADER_SIZE;
249                     h4_state = H4_W4_SCO_HEADER;
250                     break;
251 #ifdef ENABLE_EHCILL
252                 case EHCILL_GO_TO_SLEEP_IND:
253                 case EHCILL_GO_TO_SLEEP_ACK:
254                 case EHCILL_WAKE_UP_IND:
255                 case EHCILL_WAKE_UP_ACK:
256                     hci_transport_h4_ehcill_handle_command(hci_packet[0]);
257                     hci_transport_h4_reset_statemachine();
258                     break;
259 #endif
260                 default:
261                     log_error("hci_transport_h4: invalid packet type 0x%02x", hci_packet[0]);
262                     hci_transport_h4_reset_statemachine();
263                     break;
264             }
265             break;
266 
267         case H4_W4_EVENT_HEADER:
268             bytes_to_read = hci_packet[2];
269             // check Event length
270             if (bytes_to_read > (HCI_INCOMING_PACKET_BUFFER_SIZE - HCI_EVENT_HEADER_SIZE)){
271                 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);
272                 hci_transport_h4_reset_statemachine();
273                 break;
274             }
275             h4_state = H4_W4_PAYLOAD;
276             break;
277 
278         case H4_W4_ACL_HEADER:
279             bytes_to_read = little_endian_read_16( hci_packet, 3);
280             // check ACL length
281             if (bytes_to_read > (HCI_INCOMING_PACKET_BUFFER_SIZE - HCI_ACL_HEADER_SIZE)){
282                 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);
283                 hci_transport_h4_reset_statemachine();
284                 break;
285             }
286             h4_state = H4_W4_PAYLOAD;
287             break;
288 
289         case H4_W4_SCO_HEADER:
290             bytes_to_read = hci_packet[3];
291             // check SCO length
292             if (bytes_to_read > (HCI_INCOMING_PACKET_BUFFER_SIZE - HCI_SCO_HEADER_SIZE)){
293                 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);
294                 hci_transport_h4_reset_statemachine();
295                 break;
296             }
297             h4_state = H4_W4_PAYLOAD;
298             break;
299 
300         case H4_W4_ISO_HEADER:
301             bytes_to_read = little_endian_read_16( hci_packet, 3) & 0x3fff;
302             // check ISO length
303             if (bytes_to_read > (HCI_INCOMING_PACKET_BUFFER_SIZE - HCI_ACL_HEADER_SIZE)){
304                 log_error("hci_transport_h4: invalid ISO payload len %d - only space for %u", bytes_to_read, HCI_INCOMING_PACKET_BUFFER_SIZE - HCI_ISO_HEADER_SIZE);
305                 hci_transport_h4_reset_statemachine();
306                 break;
307             }
308             h4_state = H4_W4_PAYLOAD;
309             break;
310 
311         case H4_W4_PAYLOAD:
312             hci_transport_h4_packet_complete();
313             break;
314 
315         case H4_OFF:
316             bytes_to_read = 0;
317             break;
318         default:
319             btstack_assert(false);
320             break;
321     }
322 
323 #ifdef ENABLE_BAUDRATE_CHANGE_FLOWCONTROL_BUG_WORKAROUND
324     if (baudrate_change_workaround_state == BAUDRATE_CHANGE_WORKAROUND_BAUDRATE_COMMAND_SENT){
325         baudrate_change_workaround_state = BAUDRATE_CHANGE_WORKAROUND_IDLE;
326         // avoid flowcontrol problem by reading expected hci command complete event of 7 bytes in a single block read
327         h4_state = H4_W4_PAYLOAD;
328         bytes_to_read = 7;
329     }
330 #endif
331 
332     // forward packet if payload size == 0
333     if (h4_state == H4_W4_PAYLOAD && bytes_to_read == 0u) {
334         hci_transport_h4_packet_complete();
335     }
336 
337     if (h4_state != H4_OFF) {
338         hci_transport_h4_trigger_next_read();
339     }
340 }
341 
342 static void hci_transport_h4_block_sent(void){
343 
344     static const uint8_t packet_sent_event[] = { HCI_EVENT_TRANSPORT_PACKET_SENT, 0};
345 
346     switch (tx_state){
347         case TX_W4_PACKET_SENT:
348             // packet fully sent, reset state
349 #ifdef ENABLE_EHCILL
350             ehcill_tx_len = 0;
351 #endif
352             tx_state = TX_IDLE;
353 
354 #ifdef ENABLE_EHCILL
355             // notify eHCILL engine
356             hci_transport_h4_ehcill_handle_packet_sent();
357 #endif
358             // notify upper stack that it can send again
359             hci_transport_h4_packet_handler(HCI_EVENT_PACKET, (uint8_t *) &packet_sent_event[0], sizeof(packet_sent_event));
360             break;
361 
362 #ifdef ENABLE_EHCILL
363         case TX_W4_EHCILL_SENT:
364         case TX_W4_WAKEUP:
365             hci_transport_h4_ehcill_handle_ehcill_command_sent();
366             break;
367 #endif
368 
369         default:
370             break;
371     }
372 }
373 
374 static int hci_transport_h4_can_send_now(uint8_t packet_type){
375     UNUSED(packet_type);
376     return tx_state == TX_IDLE;
377 }
378 
379 static int hci_transport_h4_send_packet(uint8_t packet_type, uint8_t * packet, int size){
380 
381     // store packet type before actual data and increase size
382     uint8_t * buffer = &packet[-1];
383     uint32_t  buffer_size = size + 1;
384     buffer[0] = packet_type;
385 
386 #ifdef ENABLE_BAUDRATE_CHANGE_FLOWCONTROL_BUG_WORKAROUND
387     if ((baudrate_change_workaround_state == BAUDRATE_CHANGE_WORKAROUND_CHIPSET_DETECTED)
388     && (memcmp(buffer, baud_rate_command_prefix, sizeof(baud_rate_command_prefix)) == 0)) {
389         log_info("Baud rate command detected, expect command complete event next");
390         baudrate_change_workaround_state = BAUDRATE_CHANGE_WORKAROUND_BAUDRATE_COMMAND_SENT;
391     }
392 #endif
393 
394 #ifdef ENABLE_EHCILL
395     // store request for later
396     ehcill_tx_len   = buffer_size;
397     ehcill_tx_data  = buffer;
398     switch (ehcill_state){
399         case EHCILL_STATE_SLEEP:
400             hci_transport_h4_ehcill_trigger_wakeup();
401             return 0;
402         case EHCILL_STATE_W2_SEND_SLEEP_ACK:
403             log_info("eHILL: send next packet, state EHCILL_STATE_W2_SEND_SLEEP_ACK");
404             return 0;
405         default:
406             break;
407     }
408 #endif
409 
410     // start sending
411     tx_state = TX_W4_PACKET_SENT;
412     btstack_uart->send_block(buffer, buffer_size);
413     return 0;
414 }
415 
416 static void hci_transport_h4_init(const void * transport_config){
417     // check for hci_transport_config_uart_t
418     if (!transport_config) {
419         log_error("hci_transport_h4: no config!");
420         return;
421     }
422     if (((hci_transport_config_t*)transport_config)->type != HCI_TRANSPORT_CONFIG_UART) {
423         log_error("hci_transport_h4: config not of type != HCI_TRANSPORT_CONFIG_UART!");
424         return;
425     }
426 
427     // extract UART config from transport config
428     hci_transport_config_uart_t * hci_transport_config_uart = (hci_transport_config_uart_t*) transport_config;
429     hci_transport_h4_uart_config.baudrate    = hci_transport_config_uart->baudrate_init;
430     hci_transport_h4_uart_config.flowcontrol = hci_transport_config_uart->flowcontrol;
431     hci_transport_h4_uart_config.parity      = hci_transport_config_uart->parity;
432     hci_transport_h4_uart_config.device_name = hci_transport_config_uart->device_name;
433 
434     // set state to off
435     tx_state = TX_OFF;
436     h4_state = H4_OFF;
437 
438     // setup UART driver
439     btstack_uart->init(&hci_transport_h4_uart_config);
440     btstack_uart->set_block_received(&hci_transport_h4_block_read);
441     btstack_uart->set_block_sent(&hci_transport_h4_block_sent);
442 }
443 
444 static int hci_transport_h4_open(void){
445     // open uart driver
446     int res = btstack_uart->open();
447     if (res != 0){
448         return res;
449     }
450 
451     // init rx + tx state machines
452     hci_transport_h4_reset_statemachine();
453     hci_transport_h4_trigger_next_read();
454     tx_state = TX_IDLE;
455 
456 #ifdef ENABLE_EHCILL
457     hci_transport_h4_ehcill_open();
458 #endif
459     return 0;
460 }
461 
462 static int hci_transport_h4_close(void){
463     // set state to off
464     tx_state = TX_OFF;
465     h4_state = H4_OFF;
466 
467     // close uart driver
468     return btstack_uart->close();
469 }
470 
471 static void hci_transport_h4_register_packet_handler(void (*handler)(uint8_t packet_type, uint8_t *packet, uint16_t size)){
472     hci_transport_h4_packet_handler = handler;
473 }
474 
475 static void dummy_handler(uint8_t packet_type, uint8_t *packet, uint16_t size){
476     UNUSED(packet_type);
477     UNUSED(packet);
478     UNUSED(size);
479 }
480 
481 //
482 // --- main part of eHCILL implementation ---
483 //
484 
485 #ifdef ENABLE_EHCILL
486 
487 static void hci_transport_h4_ehcill_emit_sleep_state(int sleep_active){
488     static int last_state = 0;
489     if (sleep_active == last_state) return;
490     last_state = sleep_active;
491 
492     log_info("hci_transport_h4_ehcill_emit_sleep_state: %u", sleep_active);
493     uint8_t event[3];
494     event[0] = HCI_EVENT_TRANSPORT_SLEEP_MODE;
495     event[1] = sizeof(event) - 2;
496     event[2] = sleep_active;
497     hci_transport_h4_packet_handler(HCI_EVENT_PACKET, &event[0], sizeof(event));
498 }
499 
500 static void hci_transport_h4_ehcill_wakeup_handler(void){
501 #ifdef ENABLE_LOG_EHCILL
502     log_info("eHCILL: UART wakeup received");
503 #endif
504     hci_transport_h4_ehcill_handle_command(EHCILL_WAKEUP_SIGNAL);
505 }
506 
507 static void hci_transport_h4_ehcill_open(void){
508     hci_transport_h4_ehcill_reset_statemachine();
509 
510     // find best sleep mode to use: wake on CTS, wake on RX, none
511     btstack_uart_sleep_mode = BTSTACK_UART_SLEEP_OFF;
512     int supported_sleep_modes = 0;
513     if (btstack_uart->get_supported_sleep_modes){
514         supported_sleep_modes = btstack_uart->get_supported_sleep_modes();
515     }
516     if (supported_sleep_modes & BTSTACK_UART_SLEEP_MASK_RTS_HIGH_WAKE_ON_CTS_PULSE){
517         log_info("eHCILL: using wake on CTS");
518         btstack_uart_sleep_mode = BTSTACK_UART_SLEEP_RTS_HIGH_WAKE_ON_CTS_PULSE;
519     } else if (supported_sleep_modes & BTSTACK_UART_SLEEP_MASK_RTS_LOW_WAKE_ON_RX_EDGE){
520         log_info("eHCILL: using wake on RX");
521         btstack_uart_sleep_mode = BTSTACK_UART_SLEEP_RTS_LOW_WAKE_ON_RX_EDGE;
522     } else {
523         log_info("eHCILL: UART driver does not provide compatible sleep mode");
524     }
525     if (btstack_uart->set_wakeup_handler){
526         btstack_uart->set_wakeup_handler(&hci_transport_h4_ehcill_wakeup_handler);
527     }
528 }
529 
530 static void hci_transport_h4_echill_send_wakeup_ind(void){
531 #ifdef ENABLE_LOG_EHCILL
532     log_info("eHCILL: send WAKEUP_IND");
533 #endif
534     // update state
535     tx_state     = TX_W4_WAKEUP;
536     ehcill_state = EHCILL_STATE_W4_WAKEUP_IND_OR_ACK;
537     ehcill_command_to_send = EHCILL_WAKE_UP_IND;
538     btstack_uart->send_block(&ehcill_command_to_send, 1);
539 }
540 
541 static int hci_transport_h4_ehcill_outgoing_packet_ready(void){
542     return ehcill_tx_len != 0;
543 }
544 
545 static void hci_transport_h4_ehcill_reset_statemachine(void){
546     ehcill_state = EHCILL_STATE_AWAKE;
547 }
548 
549 static void hci_transport_h4_ehcill_send_ehcill_command(void){
550 #ifdef ENABLE_LOG_EHCILL
551     log_info("eHCILL: send command %02x", ehcill_command_to_send);
552 #endif
553     tx_state = TX_W4_EHCILL_SENT;
554     if (ehcill_command_to_send == EHCILL_GO_TO_SLEEP_ACK){
555         ehcill_state = EHCILL_STATE_SLEEP;
556     }
557     btstack_uart->send_block(&ehcill_command_to_send, 1);
558 }
559 
560 static void hci_transport_h4_ehcill_sleep_ack_timer_handler(btstack_timer_source_t * timer){
561 	UNUSED(timer);
562 #ifdef ENABLE_LOG_EHCILL
563     log_info("eHCILL: timer triggered");
564 #endif
565     hci_transport_h4_ehcill_send_ehcill_command();
566 }
567 
568 static void hci_transport_h4_ehcill_sleep_ack_timer_setup(void){
569     // setup timer
570 #ifdef ENABLE_LOG_EHCILL
571     log_info("eHCILL: set timer for sending command %02x", ehcill_command_to_send);
572 #endif
573     btstack_run_loop_set_timer_handler(&ehcill_sleep_ack_timer, &hci_transport_h4_ehcill_sleep_ack_timer_handler);
574     btstack_run_loop_set_timer(&ehcill_sleep_ack_timer, 50);
575     btstack_run_loop_add_timer(&ehcill_sleep_ack_timer);
576 }
577 
578 static void hci_transport_h4_ehcill_trigger_wakeup(void){
579     switch (tx_state){
580         case TX_W2_EHCILL_SEND:
581         case TX_W4_EHCILL_SENT:
582             // wake up / sleep ack in progress, nothing to do now
583             return;
584         case TX_IDLE:
585         default:
586             // all clear, prepare for wakeup
587             break;
588     }
589     // UART needed again
590     hci_transport_h4_ehcill_emit_sleep_state(0);
591     if (btstack_uart_sleep_mode){
592         btstack_uart->set_sleep(BTSTACK_UART_SLEEP_OFF);
593     }
594     hci_transport_h4_echill_send_wakeup_ind();
595 }
596 
597 static void hci_transport_h4_ehcill_schedule_ehcill_command(uint8_t command){
598 #ifdef ENABLE_LOG_EHCILL
599     log_info("eHCILL: schedule eHCILL command %02x", command);
600 #endif
601     ehcill_command_to_send = command;
602     switch (tx_state){
603         case TX_IDLE:
604             if (ehcill_command_to_send == EHCILL_WAKE_UP_ACK){
605                 // send right away
606                 hci_transport_h4_ehcill_send_ehcill_command();
607             } else {
608                 // change state so BTstack cannot send and setup timer
609                 tx_state = TX_W2_EHCILL_SEND;
610                 hci_transport_h4_ehcill_sleep_ack_timer_setup();
611             }
612             break;
613         default:
614             break;
615     }
616 }
617 
618 static void hci_transport_h4_ehcill_handle_command(uint8_t action){
619     // log_info("hci_transport_h4_ehcill_handle: %x, state %u, defer_rx %u", action, ehcill_state, ehcill_defer_rx_size);
620     switch(ehcill_state){
621         case EHCILL_STATE_AWAKE:
622             switch(action){
623                 case EHCILL_GO_TO_SLEEP_IND:
624                     ehcill_state = EHCILL_STATE_W2_SEND_SLEEP_ACK;
625 #ifdef ENABLE_LOG_EHCILL
626                     log_info("eHCILL: Received GO_TO_SLEEP_IND RX");
627 #endif
628                     hci_transport_h4_ehcill_schedule_ehcill_command(EHCILL_GO_TO_SLEEP_ACK);
629                     break;
630                 default:
631                     break;
632             }
633             break;
634 
635         case EHCILL_STATE_W2_SEND_SLEEP_ACK:
636             switch(action){
637                 case EHCILL_WAKE_UP_IND:
638                     ehcill_state = EHCILL_STATE_AWAKE;
639                     hci_transport_h4_ehcill_emit_sleep_state(0);
640                     if (btstack_uart_sleep_mode){
641                         btstack_uart->set_sleep(BTSTACK_UART_SLEEP_OFF);
642                     }
643 #ifdef ENABLE_LOG_EHCILL
644                     log_info("eHCILL: Received WAKE_UP_IND RX");
645 #endif
646                     hci_transport_h4_ehcill_schedule_ehcill_command(EHCILL_WAKE_UP_ACK);
647                     break;
648 
649                 default:
650                     break;
651             }
652             break;
653 
654         case EHCILL_STATE_SLEEP:
655             switch(action){
656                 case EHCILL_WAKEUP_SIGNAL:
657                     hci_transport_h4_ehcill_emit_sleep_state(0);
658                     if (btstack_uart_sleep_mode){
659                         btstack_uart->set_sleep(BTSTACK_UART_SLEEP_OFF);
660                     }
661                     break;
662                 case EHCILL_WAKE_UP_IND:
663                     ehcill_state = EHCILL_STATE_AWAKE;
664                     hci_transport_h4_ehcill_emit_sleep_state(0);
665                     if (btstack_uart_sleep_mode){
666                         btstack_uart->set_sleep(BTSTACK_UART_SLEEP_OFF);
667                     }
668 #ifdef ENABLE_LOG_EHCILL
669                     log_info("eHCILL: Received WAKE_UP_IND RX");
670 #endif
671                     hci_transport_h4_ehcill_schedule_ehcill_command(EHCILL_WAKE_UP_ACK);
672                     break;
673 
674                 default:
675                     break;
676             }
677             break;
678 
679         case EHCILL_STATE_W4_WAKEUP_IND_OR_ACK:
680             switch(action){
681                 case EHCILL_WAKE_UP_IND:
682                 case EHCILL_WAKE_UP_ACK:
683 #ifdef ENABLE_LOG_EHCILL
684                     log_info("eHCILL: Received WAKE_UP (%02x)", action);
685 #endif
686                     tx_state = TX_W4_PACKET_SENT;
687                     ehcill_state = EHCILL_STATE_AWAKE;
688                     btstack_uart->send_block(ehcill_tx_data, ehcill_tx_len);
689                     break;
690                 default:
691                     break;
692             }
693             break;
694     }
695 }
696 
697 static void hci_transport_h4_ehcill_handle_packet_sent(void){
698 #ifdef ENABLE_LOG_EHCILL
699         log_info("eHCILL: handle packet sent, command to send %02x", ehcill_command_to_send);
700 #endif
701     // now, send pending ehcill command if neccessary
702     switch (ehcill_command_to_send){
703         case EHCILL_GO_TO_SLEEP_ACK:
704             hci_transport_h4_ehcill_sleep_ack_timer_setup();
705             break;
706         case EHCILL_WAKE_UP_IND:
707             hci_transport_h4_ehcill_send_ehcill_command();
708             break;
709         default:
710             break;
711     }
712 }
713 
714 static void hci_transport_h4_ehcill_handle_ehcill_command_sent(void){
715     tx_state = TX_IDLE;
716     int command = ehcill_command_to_send;
717     ehcill_command_to_send = 0;
718 
719 #ifdef ENABLE_LOG_EHCILL
720         log_info("eHCILL: handle eHCILL sent, command was %02x", command);
721 #endif
722 
723     if (command == EHCILL_GO_TO_SLEEP_ACK) {
724 #ifdef ENABLE_LOG_EHCILL
725         log_info("eHCILL: GO_TO_SLEEP_ACK sent, enter sleep mode");
726 #endif
727         // UART not needed after EHCILL_GO_TO_SLEEP_ACK was sent
728         if (btstack_uart_sleep_mode != BTSTACK_UART_SLEEP_OFF){
729             btstack_uart->set_sleep(btstack_uart_sleep_mode);
730         }
731         hci_transport_h4_ehcill_emit_sleep_state(1);
732     }
733     // already packet ready? then start wakeup
734     if (hci_transport_h4_ehcill_outgoing_packet_ready()){
735         hci_transport_h4_ehcill_emit_sleep_state(0);
736         if (btstack_uart_sleep_mode != BTSTACK_UART_SLEEP_OFF){
737             btstack_uart->set_sleep(BTSTACK_UART_SLEEP_OFF);
738         }
739         if (command != EHCILL_WAKE_UP_IND){
740             hci_transport_h4_echill_send_wakeup_ind();
741         }
742     }
743 }
744 
745 #endif
746 // --- end of eHCILL implementation ---------
747 
748 
749 // configure and return h4 singleton
750 static const hci_transport_t hci_transport_h4 = {
751         /* const char * name; */                                        "H4",
752         /* void   (*init) (const void *transport_config); */            &hci_transport_h4_init,
753         /* int    (*open)(void); */                                     &hci_transport_h4_open,
754         /* int    (*close)(void); */                                    &hci_transport_h4_close,
755         /* void   (*register_packet_handler)(void (*handler)(...); */   &hci_transport_h4_register_packet_handler,
756         /* int    (*can_send_packet_now)(uint8_t packet_type); */       &hci_transport_h4_can_send_now,
757         /* int    (*send_packet)(...); */                               &hci_transport_h4_send_packet,
758         /* int    (*set_baudrate)(uint32_t baudrate); */                &hci_transport_h4_set_baudrate,
759         /* void   (*reset_link)(void); */                               NULL,
760         /* void   (*set_sco_config)(uint16_t voice_setting, int num_connections); */ NULL,
761 };
762 
763 const hci_transport_t * hci_transport_h4_instance_for_uart(const btstack_uart_t * uart_driver){
764     btstack_uart = uart_driver;
765     return &hci_transport_h4;
766 }
767 
768 // @deprecated
769 const hci_transport_t * hci_transport_h4_instance(const btstack_uart_block_t * uart_driver) {
770     btstack_uart = (const btstack_uart_t *) uart_driver;
771     return &hci_transport_h4;
772 }
773