xref: /btstack/platform/libusb/hci_transport_h2_libusb.c (revision abe9af1a35c0075cd8cb2b7884ccceb44fde6174)
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_h2_libusb.c"
39 
40 /*
41  *  hci_transport_usb.c
42  *
43  *  HCI Transport API implementation for USB
44  *
45  *  Created by Matthias Ringwald on 7/5/09.
46  */
47 
48 // Interface Number - Alternate Setting - suggested Endpoint Address - Endpoint Type - Suggested Max Packet Size
49 // HCI Commands 0 0 0x00 Control 8/16/32/64
50 // HCI Events   0 0 0x81 Interrupt (IN) 16
51 // ACL Data     0 0 0x82 Bulk (IN) 32/64
52 // ACL Data     0 0 0x02 Bulk (OUT) 32/64
53 // SCO Data     0 0 0x83 Isochronous (IN)
54 // SCO Data     0 0 0x03 Isochronous (Out)
55 
56 #include <strings.h>
57 #include <string.h>
58 #include <unistd.h>   /* UNIX standard function definitions */
59 #include <sys/types.h>
60 
61 #include <libusb.h>
62 
63 // bail out if seen libusb is apperently to old
64 #if !defined(LIBUSB_API_VERSION) || (LIBUSB_API_VERSION < 0x01000104)
65 #error libusb api version to old!
66 #endif
67 
68 #include <poll.h>
69 
70 #include "btstack_config.h"
71 
72 #include "btstack_debug.h"
73 #include "hci.h"
74 #include "hci_transport.h"
75 #include "hci_transport_usb.h"
76 
77 #define DEBUG
78 
79 // deal with changes in libusb API:
80 #ifdef LIBUSB_API_VERSION
81 #if LIBUSB_API_VERSION >= 0x01000106
82 // since 1.0.22, libusb_set_option replaces libusb_set_debug
83 #define libusb_set_debug(context,level) libusb_set_option(context, LIBUSB_OPTION_LOG_LEVEL, level)
84 #endif
85 #endif
86 
87 #if (USB_VENDOR_ID != 0) && (USB_PRODUCT_ID != 0)
88 #define HAVE_USB_VENDOR_ID_AND_PRODUCT_ID
89 #endif
90 
91 #define ACL_IN_BUFFER_COUNT    3
92 #define EVENT_IN_BUFFER_COUNT  3
93 #define EVENT_OUT_BUFFER_COUNT 4
94 #define SCO_IN_BUFFER_COUNT   10
95 
96 #define ASYNC_POLLING_INTERVAL_MS 1
97 
98 //
99 // Bluetooth USB Transport Alternate Settings:
100 //
101 // 0: No active voice channels (for USB compliance)
102 // 1: One 8 kHz voice channel with 8-bit encoding
103 // 2: Two 8 kHz voice channels with 8-bit encoding or one 8 kHz voice channel with 16-bit encoding
104 // 3: Three 8 kHz voice channels with 8-bit encoding
105 // 4: Two 8 kHz voice channels with 16-bit encoding or one 16 kHz voice channel with 16-bit encoding
106 // 5: Three 8 kHz voice channels with 16-bit encoding or one 8 kHz voice channel with 16-bit encoding and one 16 kHz voice channel with 16-bit encoding
107 // --> support only a single SCO connection
108 // #define ALT_SETTING (1)
109 
110 #ifdef ENABLE_SCO_OVER_HCI
111 // alt setting for 1-3 connections and 8/16 bit
112 static const int alt_setting_8_bit[]  = {1,2,3};
113 static const int alt_setting_16_bit[] = {2,4,5};
114 
115 // for ALT_SETTING >= 1 and 8-bit channel, we need the following isochronous packets
116 // One complete SCO packet with 24 frames every 3 frames (== 3 ms)
117 #define NUM_ISO_PACKETS (3)
118 
119 static const uint16_t iso_packet_size_for_alt_setting[] = {
120     0,
121     9,
122     17,
123     25,
124     33,
125     49,
126     63,
127 };
128 #endif
129 
130 // 49 bytes is the max usb packet size for alternate setting 5 (Three 8 kHz 16-bit channels or one 8 kHz 16-bit channel and one 16 kHz 16-bit channel)
131 // note: alt setting 6 has max packet size of 63 every 7.5 ms = 472.5 bytes / HCI packet, while max SCO packet has 255 byte payload
132 #define SCO_PACKET_SIZE  (49 * NUM_ISO_PACKETS)
133 
134 // Outgoing SCO packet queue
135 // simplified ring buffer implementation
136 #define SCO_OUT_BUFFER_COUNT  (20)
137 #define SCO_OUT_BUFFER_SIZE (SCO_OUT_BUFFER_COUNT * SCO_PACKET_SIZE)
138 
139 // seems to be the max depth for USB 3
140 #define USB_MAX_PATH_LEN 7
141 
142 // prototypes
143 static void dummy_handler(uint8_t packet_type, uint8_t *packet, uint16_t size);
144 static int usb_close(void);
145 
146 typedef enum {
147     LIB_USB_CLOSED = 0,
148     LIB_USB_OPENED,
149     LIB_USB_DEVICE_OPENDED,
150     LIB_USB_INTERFACE_CLAIMED,
151     LIB_USB_TRANSFERS_ALLOCATED
152 } libusb_state_t;
153 
154 // SCO packet state machine
155 typedef enum {
156     H2_W4_SCO_HEADER = 1,
157     H2_W4_PAYLOAD,
158 } H2_SCO_STATE;
159 
160 static libusb_state_t libusb_state = LIB_USB_CLOSED;
161 
162 // single instance
163 static hci_transport_t * hci_transport_usb = NULL;
164 
165 static void (*packet_handler)(uint8_t packet_type, uint8_t *packet, uint16_t size) = dummy_handler;
166 
167 // libusb
168 #ifndef HAVE_USB_VENDOR_ID_AND_PRODUCT_ID
169 static struct libusb_device_descriptor desc;
170 #endif
171 static libusb_device_handle * handle;
172 
173 // known devices
174 typedef struct {
175     btstack_linked_item_t next;
176     uint16_t vendor_id;
177     uint16_t product_id;
178 } usb_known_device_t;
179 
180 static btstack_linked_list_t usb_knwon_devices;
181 
182 typedef struct list_head {
183     struct list_head *next, *prev;
184 } list_head_t;
185 
186 static inline void __list_add( list_head_t *new, list_head_t *prev, list_head_t *next ) {
187     next->prev = new;
188     new->next = next;
189     new->prev = prev;
190     prev->next = new;
191 }
192 
193 #define LIST_HEAD_INIT(name) { &(name), &(name) }
194 
195 static inline void init_list_head( list_head_t *list ) {
196     list->next = list;
197     list->prev = list;
198 }
199 
200 static inline void list_add( list_head_t *new, list_head_t *head ) {
201     __list_add( new, head, head->next );
202 }
203 
204 static inline void list_add_tail( list_head_t *new, list_head_t *head ) {
205     __list_add( new, head->prev, head );
206 }
207 
208 static inline void list_del( list_head_t *entry ) {
209     entry->next->prev = entry->prev;
210     entry->prev->next = entry->next;
211 
212     entry->prev = NULL;
213     entry->next = NULL;
214 }
215 
216 static inline bool list_empty( list_head_t *head ) {
217     return head->next == head;
218 }
219 
220 static inline list_head_t *list_pop_front( list_head_t *head ) {
221     list_head_t *front = head->next;
222     list_del( front );
223     return front;
224 }
225 
226 
227 typedef struct {
228     list_head_t list;
229     struct libusb_transfer *t;
230     uint8_t *data;
231     bool in_flight;
232 } usb_transfer_list_entry_t;
233 
234 typedef struct {
235     list_head_t transfers;
236     int nbr;
237     usb_transfer_list_entry_t entries[0];
238 } usb_transfer_list_t;
239 
240 static struct libusb_transfer *usb_transfer_list_acquire( usb_transfer_list_t *list ) {
241     usb_transfer_list_entry_t *current = (usb_transfer_list_entry_t*)list_pop_front( &list->transfers );
242     struct libusb_transfer *transfer = current->t;
243     current->in_flight = true;
244     return transfer;
245 }
246 void usb_transfer_list_free( usb_transfer_list_t *list );
247 
248 static void usb_transfer_list_release( usb_transfer_list_t *list, struct libusb_transfer *transfer ) {
249     usb_transfer_list_entry_t *current = (usb_transfer_list_entry_t*)transfer->user_data;
250     assert( current != NULL );
251     current->in_flight = false;
252     list_add( &current->list, &list->transfers );
253 }
254 
255 static bool usb_transfer_list_empty( usb_transfer_list_t *list ) {
256     return list_empty( &list->transfers );
257 }
258 
259 static usb_transfer_list_t *usb_transfer_list_alloc( int nbr, int iso_packets, int length ) {
260     usb_transfer_list_t *list = malloc( sizeof(usb_transfer_list_t) + nbr*sizeof(usb_transfer_list_entry_t) );
261     init_list_head( &list->transfers );
262     list->nbr = nbr;
263     for( int i=0; i<nbr; ++i )
264     {
265         usb_transfer_list_entry_t *entry = &list->entries[i];
266         struct libusb_transfer *transfer = libusb_alloc_transfer(iso_packets);
267         entry->data = malloc( length );
268         transfer->buffer = entry->data;
269         transfer->user_data = entry;
270         entry->t = transfer;
271         usb_transfer_list_release( list, transfer );
272         assert( entry->t->user_data != NULL );
273     }
274     return list;
275 }
276 
277 static void usb_transfer_list_cancel( usb_transfer_list_t *list ) {
278 #ifdef __APPLE__
279     // for darwin ignore all warnings
280     libusb_set_debug(NULL, LIBUSB_LOG_LEVEL_ERROR);
281 #endif
282     for( int i=0; i<list->nbr; ++i ) {
283         usb_transfer_list_entry_t *current = &list->entries[i];
284         if( current->in_flight ) {
285             libusb_cancel_transfer( current->t );
286         }
287     }
288 #ifdef __APPLE__
289     libusb_set_debug(NULL, LIBUSB_LOG_LEVEL_WARNING);
290 #endif
291 }
292 
293 static int usb_transfer_list_in_flight( usb_transfer_list_t *list ) {
294     int cnt = 0;
295     for(int i=0; i<list->nbr; ++i) {
296         usb_transfer_list_entry_t *entry = &list->entries[i];
297         if( entry->in_flight ) {
298             ++cnt;
299         }
300     }
301     return cnt;
302 }
303 
304 
305 static void usb_transfer_list_free_entry( struct libusb_transfer *transfer ) {
306     usb_transfer_list_entry_t *current = (usb_transfer_list_entry_t*)transfer->user_data;
307     free( current->data );
308     libusb_free_transfer( transfer );
309     current->in_flight = false;
310     current->t = NULL;
311     current->data = NULL;
312 }
313 
314 void usb_transfer_list_free( usb_transfer_list_t *list ) {
315     for( int i=0; i<list->nbr; ++i ) {
316         usb_transfer_list_entry_t *entry = &list->entries[i];
317         assert( entry->in_flight == false );
318         if( entry->t ) {
319             usb_transfer_list_free_entry( entry->t );
320         }
321     }
322     free( list );
323 }
324 
325 static usb_transfer_list_t *default_transfer_list = NULL;
326 
327 // For (ab)use as a linked list of received packets
328 static list_head_t handle_packet_list = LIST_HEAD_INIT(handle_packet_list);
329 
330 static void enqueue_transfer(struct libusb_transfer *transfer) {
331     usb_transfer_list_entry_t *current = (usb_transfer_list_entry_t*)transfer->user_data;
332     assert( current != NULL );
333     list_add_tail( &current->list, &handle_packet_list );
334 }
335 
336 static void signal_acknowledge(void);
337 static void signal_sco_can_send_now(void);
338 
339 #ifdef ENABLE_SCO_OVER_HCI
340 
341 #ifdef _WIN32
342 #error "SCO not working on Win32 (Windows 8, libusb 1.0.19, Zadic WinUSB), please uncomment ENABLE_SCO_OVER_HCI in btstack-config.h for now"
343 #endif
344 
345 // incoming SCO
346 static H2_SCO_STATE sco_state;
347 static uint8_t  sco_buffer[255+3 + SCO_PACKET_SIZE];
348 static uint16_t sco_read_pos;
349 static uint16_t sco_bytes_to_read;
350 
351 // pause/resume
352 static uint16_t sco_voice_setting;
353 static int      sco_num_connections;
354 static bool     sco_activated;
355 
356 // dynamic SCO configuration
357 static uint16_t iso_packet_size;
358 static int      sco_enabled;
359 
360 usb_transfer_list_t *sco_transfer_list = NULL;
361 
362 #endif
363 
364 
365 static int doing_pollfds;
366 static int num_pollfds;
367 static btstack_data_source_t * pollfd_data_sources;
368 
369 static void usb_transport_response_ds(btstack_data_source_t *ds, btstack_data_source_callback_type_t callback_type);
370 static btstack_data_source_t transport_response;
371 
372 static btstack_timer_source_t usb_timer;
373 static int usb_timer_active;
374 
375 // endpoint addresses
376 static int event_in_addr;
377 static int acl_in_addr;
378 static int acl_out_addr;
379 static int sco_in_addr;
380 static int sco_out_addr;
381 
382 // device info
383 static int usb_path_len;
384 static uint8_t usb_path[USB_MAX_PATH_LEN];
385 static uint16_t usb_vendor_id;
386 static uint16_t usb_product_id;
387 
388 // transport interface state
389 static int usb_transport_open;
390 
391 static void hci_transport_h2_libusb_emit_usb_info(void) {
392     uint8_t event[7 + USB_MAX_PATH_LEN];
393     uint16_t pos = 0;
394     event[pos++] = HCI_EVENT_TRANSPORT_USB_INFO;
395     event[pos++] = 5 + usb_path_len;
396     little_endian_store_16(event, pos, usb_vendor_id);
397     pos+=2;
398     little_endian_store_16(event, pos, usb_product_id);
399     pos+=2;
400     event[pos++] = usb_path_len;
401     memcpy(&event[pos], usb_path, usb_path_len);
402     pos += usb_path_len;
403     (*packet_handler)(HCI_EVENT_PACKET, event, pos);
404 }
405 
406 void hci_transport_usb_add_device(uint16_t vendor_id, uint16_t product_id) {
407     usb_known_device_t * device = malloc(sizeof(usb_known_device_t));
408     if (device != NULL) {
409         device->vendor_id = vendor_id;
410         device->product_id = product_id;
411         btstack_linked_list_add(&usb_knwon_devices, (btstack_linked_item_t *) device);
412     }
413 }
414 
415 void hci_transport_usb_set_path(int len, uint8_t * port_numbers){
416     if (len > USB_MAX_PATH_LEN || !port_numbers){
417         log_error("hci_transport_usb_set_path: len or port numbers invalid");
418         return;
419     }
420     usb_path_len = len;
421     memcpy(usb_path, port_numbers, len);
422 }
423 
424 LIBUSB_CALL static void async_callback(struct libusb_transfer *transfer) {
425     if (libusb_state != LIB_USB_TRANSFERS_ALLOCATED) {
426         log_info("shutdown, transfer %p", transfer);
427         usb_transfer_list_free_entry( transfer );
428         return;
429     }
430 
431     int r;
432     // log_info("begin async_callback endpoint %x, status %x, actual length %u", transfer->endpoint, transfer->status, transfer->actual_length );
433 
434     if (transfer->status == LIBUSB_TRANSFER_COMPLETED) {
435         enqueue_transfer(transfer);
436     } else if (transfer->status == LIBUSB_TRANSFER_STALL){
437         log_info("-> Transfer stalled, trying again");
438         r = libusb_clear_halt(handle, transfer->endpoint);
439         if (r) {
440             log_error("Error rclearing halt %d", r);
441         }
442         r = libusb_submit_transfer(transfer);
443         if (r) {
444             log_error("Error re-submitting transfer %d", r);
445         }
446     } else if ( transfer->status == LIBUSB_TRANSFER_CANCELLED ) {
447 #ifdef ENABLE_SCO_OVER_HCI
448         if(( transfer->endpoint == sco_in_addr) || (transfer->endpoint == sco_out_addr)) {
449             usb_transfer_list_release( sco_transfer_list, transfer );
450         } else {
451 #endif
452             usb_transfer_list_release( default_transfer_list, transfer );
453 #ifdef ENABLE_SCO_OVER_HCI
454         }
455 #endif
456     } else {
457         log_info("async_callback. not data -> resubmit transfer, endpoint %x, status %x, length %u", transfer->endpoint, transfer->status, transfer->actual_length);
458         // No usable data, just resubmit packet
459         r = libusb_submit_transfer(transfer);
460         if (r) {
461             log_error("Error re-submitting transfer %d", r);
462         }
463     }
464     // log_info("end async_callback");
465 }
466 
467 
468 #ifdef ENABLE_SCO_OVER_HCI
469 static int usb_send_sco_packet(uint8_t *packet, int size){
470     int r;
471 
472     if( !sco_activated ) {
473         log_error("sco send without beeing active!");
474         return -1;
475     }
476 
477     if (libusb_state != LIB_USB_TRANSFERS_ALLOCATED) return -1;
478 
479     struct libusb_transfer *transfer = usb_transfer_list_acquire( sco_transfer_list );
480     uint8_t *data = transfer->buffer;
481     void *user_data = transfer->user_data;
482 
483     // log_info("usb_send_acl_packet enter, size %u", size);
484 
485     // store packet in free slot
486     memcpy(data, packet, size);
487 
488     // setup transfer
489     // log_info("usb_send_sco_packet: size %u, max size %u, iso packet size %u", size, NUM_ISO_PACKETS * iso_packet_size, iso_packet_size);
490     libusb_fill_iso_transfer(transfer, handle, sco_out_addr, data, NUM_ISO_PACKETS * iso_packet_size, NUM_ISO_PACKETS, async_callback, user_data, 0);
491     libusb_set_iso_packet_lengths(transfer, iso_packet_size);
492     r = libusb_submit_transfer(transfer);
493     if (r < 0) {
494         log_error("Error submitting sco transfer, %d", r);
495         return -1;
496     }
497 
498     // log_info("H2: queued packet at index %u, num active %u", tranfer_index, sco_out_transfers_active);
499     signal_acknowledge();
500 
501     if( !usb_transfer_list_empty( sco_transfer_list ) ) {
502         signal_sco_can_send_now();
503     }
504 
505     return 0;
506 }
507 
508 static void sco_state_machine_init(void){
509     sco_state = H2_W4_SCO_HEADER;
510     sco_read_pos = 0;
511     sco_bytes_to_read = 3;
512 }
513 
514 static void handle_isochronous_data(uint8_t * buffer, uint16_t size){
515     while (size){
516         if (size < sco_bytes_to_read){
517             // just store incomplete data
518             memcpy(&sco_buffer[sco_read_pos], buffer, size);
519             sco_read_pos      += size;
520             sco_bytes_to_read -= size;
521             return;
522         }
523         // copy requested data
524         memcpy(&sco_buffer[sco_read_pos], buffer, sco_bytes_to_read);
525         sco_read_pos += sco_bytes_to_read;
526         buffer       += sco_bytes_to_read;
527         size         -= sco_bytes_to_read;
528 
529         // chunk read successfully, next action
530         switch (sco_state){
531             case H2_W4_SCO_HEADER:
532                 sco_state = H2_W4_PAYLOAD;
533                 sco_bytes_to_read = sco_buffer[2];
534                 break;
535             case H2_W4_PAYLOAD:
536                 // packet complete
537                 packet_handler(HCI_SCO_DATA_PACKET, sco_buffer, sco_read_pos);
538                 sco_state_machine_init();
539                 break;
540 			default:
541 				btstack_assert(false);
542 				break;
543         }
544     }
545 }
546 #endif
547 
548 static void handle_completed_transfer(struct libusb_transfer *transfer){
549 
550     int resubmit = 0;
551     assert(transfer->user_data != NULL );
552     if (transfer->endpoint == event_in_addr) {
553         packet_handler(HCI_EVENT_PACKET, transfer->buffer, transfer->actual_length);
554         resubmit = 1;
555     } else if (transfer->endpoint == acl_in_addr) {
556         // log_info("-> acl");
557         packet_handler(HCI_ACL_DATA_PACKET, transfer->buffer, transfer->actual_length);
558         resubmit = 1;
559     } else if (transfer->endpoint == 0){
560         // log_info("command done, size %u", transfer->actual_length);
561 //        printf("%s cmd release\n", __FUNCTION__ );
562         usb_transfer_list_release( default_transfer_list, transfer );
563     } else if (transfer->endpoint == acl_out_addr){
564         // log_info("acl out done, size %u", transfer->actual_length);
565 //        printf("%s acl release\n", __FUNCTION__ );
566         usb_transfer_list_release( default_transfer_list, transfer );
567 #ifdef ENABLE_SCO_OVER_HCI
568     } else if (transfer->endpoint == sco_in_addr) {
569         // log_info("handle_completed_transfer for SCO IN! num packets %u", transfer->NUM_ISO_PACKETS);
570 
571         // give the transfer back to the pool, without resubmiting
572         if( !sco_activated ) {
573             usb_transfer_list_release( sco_transfer_list, transfer );
574             return;
575         }
576 
577         int i;
578         for (i = 0; i < transfer->num_iso_packets; i++) {
579             struct libusb_iso_packet_descriptor *pack = &transfer->iso_packet_desc[i];
580             if (pack->status != LIBUSB_TRANSFER_COMPLETED) {
581                 log_error("Error: pack %u status %d\n", i, pack->status);
582                 continue;
583             }
584             if (!pack->actual_length) continue;
585             uint8_t * data = libusb_get_iso_packet_buffer_simple(transfer, i);
586             handle_isochronous_data(data, pack->actual_length);
587         }
588         resubmit = 1;
589     } else if (transfer->endpoint == sco_out_addr){
590         int i;
591         for (i = 0; i < transfer->num_iso_packets; i++) {
592             struct libusb_iso_packet_descriptor *pack = &transfer->iso_packet_desc[i];
593             if (pack->status != LIBUSB_TRANSFER_COMPLETED) {
594                 log_error("Error: pack %u status %d\n", i, pack->status);
595             }
596         }
597         usb_transfer_list_release( sco_transfer_list, transfer );
598         if( !sco_activated ) {
599             return;
600         }
601         // log_info("sco out done, {{ %u/%u (%x)}, { %u/%u (%x)}, { %u/%u (%x)}}",
602         //     transfer->iso_packet_desc[0].actual_length, transfer->iso_packet_desc[0].length, transfer->iso_packet_desc[0].status,
603         //     transfer->iso_packet_desc[1].actual_length, transfer->iso_packet_desc[1].length, transfer->iso_packet_desc[1].status,
604         //     transfer->iso_packet_desc[2].actual_length, transfer->iso_packet_desc[2].length, transfer->iso_packet_desc[2].status);
605         // notify upper layer if there's space for new SCO packets
606 
607         if (!usb_transfer_list_empty(sco_transfer_list)) {
608             signal_sco_can_send_now();
609         }
610         // log_info("H2: sco out complete, num active num active %u", sco_out_transfers_active);
611 #endif
612     } else {
613         log_info("usb_process_ds endpoint unknown %x", transfer->endpoint);
614     }
615 
616     if (libusb_state != LIB_USB_TRANSFERS_ALLOCATED) return;
617 
618     if (resubmit){
619         // Re-submit transfer
620         int r = libusb_submit_transfer(transfer);
621         if (r) {
622             log_error("Error re-submitting transfer %d", r);
623         }
624     }
625 }
626 
627 void usb_handle_pending_events(void);
628 void usb_handle_pending_events(void) {
629     struct timeval tv = { 0 };
630     libusb_handle_events_timeout_completed(NULL, &tv, NULL);
631 }
632 
633 static void usb_process_ds(btstack_data_source_t *ds, btstack_data_source_callback_type_t callback_type) {
634 
635     UNUSED(ds);
636     UNUSED(callback_type);
637 
638    if (libusb_state != LIB_USB_TRANSFERS_ALLOCATED) return;
639 
640     // log_info("begin usb_process_ds");
641     // always handling an event as we're called when data is ready
642     usb_handle_pending_events();
643 
644     // Handle any packet in the order that they were received
645     while (!list_empty(&handle_packet_list)) {
646         // log_info("handle packet %p, endpoint %x, status %x", handle_packet, handle_packet->endpoint, handle_packet->status);
647 
648         // pop next transfer
649         usb_transfer_list_entry_t *current = (usb_transfer_list_entry_t*)list_pop_front( &handle_packet_list );
650 
651         // handle transfer
652         handle_completed_transfer(current->t);
653 
654         // handle case where libusb_close might be called by hci packet handler
655         if (libusb_state != LIB_USB_TRANSFERS_ALLOCATED) return;
656     }
657     // log_info("end usb_process_ds");
658 }
659 
660 static void usb_process_ts(btstack_timer_source_t *timer) {
661 
662     UNUSED(timer);
663 
664     // log_info("in usb_process_ts");
665 
666     // timer is deactive, when timer callback gets called
667     usb_timer_active = 0;
668 
669     if (libusb_state != LIB_USB_TRANSFERS_ALLOCATED) return;
670 
671     // actually handled the packet in the pollfds function
672     usb_process_ds((struct btstack_data_source *) NULL, DATA_SOURCE_CALLBACK_READ);
673 
674     // Get the amount of time until next event is due
675     long msec = ASYNC_POLLING_INTERVAL_MS;
676 
677     // Activate timer
678     btstack_run_loop_set_timer(&usb_timer, msec);
679     btstack_run_loop_add_timer(&usb_timer);
680     usb_timer_active = 1;
681 
682     return;
683 }
684 
685 
686 static int scan_for_bt_endpoints(libusb_device *dev) {
687     int r;
688 
689     event_in_addr = 0;
690     acl_in_addr = 0;
691     acl_out_addr = 0;
692     sco_out_addr = 0;
693     sco_in_addr = 0;
694 
695     // get endpoints from interface descriptor
696     struct libusb_config_descriptor *config_descriptor;
697     r = libusb_get_active_config_descriptor(dev, &config_descriptor);
698     if (r < 0) return r;
699 
700     int num_interfaces = config_descriptor->bNumInterfaces;
701     log_info("active configuration has %u interfaces", num_interfaces);
702 
703     int i;
704     for (i = 0; i < num_interfaces ; i++){
705         const struct libusb_interface *interface = &config_descriptor->interface[i];
706         const struct libusb_interface_descriptor * interface_descriptor = interface->altsetting;
707         log_info("interface %u: %u endpoints", i, interface_descriptor->bNumEndpoints);
708 
709         const struct libusb_endpoint_descriptor *endpoint = interface_descriptor->endpoint;
710 
711         for (r=0;r<interface_descriptor->bNumEndpoints;r++,endpoint++){
712             log_info("- endpoint %x, attributes %x", endpoint->bEndpointAddress, endpoint->bmAttributes);
713 
714             switch (endpoint->bmAttributes & 0x3){
715                 case LIBUSB_TRANSFER_TYPE_INTERRUPT:
716                     if (event_in_addr) continue;
717                     event_in_addr = endpoint->bEndpointAddress;
718                     log_info("-> using 0x%2.2X for HCI Events", event_in_addr);
719                     break;
720                 case LIBUSB_TRANSFER_TYPE_BULK:
721                     if (endpoint->bEndpointAddress & 0x80) {
722                         if (acl_in_addr) continue;
723                         acl_in_addr = endpoint->bEndpointAddress;
724                         log_info("-> using 0x%2.2X for ACL Data In", acl_in_addr);
725                     } else {
726                         if (acl_out_addr) continue;
727                         acl_out_addr = endpoint->bEndpointAddress;
728                         log_info("-> using 0x%2.2X for ACL Data Out", acl_out_addr);
729                     }
730                     break;
731                 case LIBUSB_TRANSFER_TYPE_ISOCHRONOUS:
732                     if (endpoint->bEndpointAddress & 0x80) {
733                         if (sco_in_addr) continue;
734                         sco_in_addr = endpoint->bEndpointAddress;
735                         log_info("-> using 0x%2.2X for SCO Data In", sco_in_addr);
736                     } else {
737                         if (sco_out_addr) continue;
738                         sco_out_addr = endpoint->bEndpointAddress;
739                         log_info("-> using 0x%2.2X for SCO Data Out", sco_out_addr);
740                     }
741                     break;
742                 default:
743                     break;
744             }
745         }
746     }
747     libusb_free_config_descriptor(config_descriptor);
748     return 0;
749 }
750 
751 #ifndef HAVE_USB_VENDOR_ID_AND_PRODUCT_ID
752 
753 // list of known devices, using VendorID/ProductID tuples
754 static const uint16_t known_bluetooth_devices[] = {
755     // BCM20702A0 - DeLOCK Bluetooth 4.0
756     0x0a5c, 0x21e8,
757     // BCM20702A0 - Asus BT400
758     0x0b05, 0x17cb,
759     // BCM20702B0 - Generic USB Detuned Class 1 @ 20 MHz
760     0x0a5c, 0x22be,
761     // nRF5x Zephyr USB HCI, e.g nRF52840-PCA10056
762     0x2fe3, 0x0100,
763     0x2fe3, 0x000b,
764 };
765 
766 static int num_known_devices = sizeof(known_bluetooth_devices) / sizeof(uint16_t) / 2;
767 
768 static int is_known_bt_device(uint16_t vendor_id, uint16_t product_id){
769     int i;
770     for (i=0; i<num_known_devices; i++){
771         if (known_bluetooth_devices[i*2] == vendor_id && known_bluetooth_devices[i*2+1] == product_id){
772             return 1;
773         }
774     }
775     btstack_linked_list_iterator_t it;
776     btstack_linked_list_iterator_init(&it, &usb_knwon_devices);
777     while (btstack_linked_list_iterator_has_next(&it)) {
778         usb_known_device_t * device = (usb_known_device_t *) btstack_linked_list_iterator_next(&it);
779         if (device->vendor_id != vendor_id) continue;
780         if (device->product_id != product_id) continue;
781         return 1;
782     }
783     return 0;
784 }
785 
786 // returns index of found device or -1
787 static int scan_for_bt_device(libusb_device **devs, int start_index) {
788     int i;
789     for (i = start_index; devs[i] ; i++){
790         libusb_device * dev = devs[i];
791         int r = libusb_get_device_descriptor(dev, &desc);
792         if (r < 0) {
793             log_error("failed to get device descriptor");
794             return 0;
795         }
796 
797         log_info("%04x:%04x (bus %d, device %d) - class %x subclass %x protocol %x ",
798                desc.idVendor, desc.idProduct,
799                libusb_get_bus_number(dev), libusb_get_device_address(dev),
800                desc.bDeviceClass, desc.bDeviceSubClass, desc.bDeviceProtocol);
801 
802         // Detect USB Dongle based Class, Subclass, and Protocol
803         // The class code (bDeviceClass) is 0xE0 – Wireless Controller.
804         // The SubClass code (bDeviceSubClass) is 0x01 – RF Controller.
805         // The Protocol code (bDeviceProtocol) is 0x01 – Bluetooth programming.
806         if (desc.bDeviceClass == 0xE0 && desc.bDeviceSubClass == 0x01 && desc.bDeviceProtocol == 0x01) {
807             return i;
808         }
809 
810         // Detect USB Dongle based on whitelist
811         if (is_known_bt_device(desc.idVendor, desc.idProduct)) {
812             return i;
813         }
814     }
815     return -1;
816 }
817 #endif
818 
819 static int prepare_device(libusb_device_handle * aHandle){
820 
821     // get device path
822     libusb_device * device = libusb_get_device(aHandle);
823     usb_path_len = libusb_get_port_numbers(device, usb_path, USB_MAX_PATH_LEN);
824 
825     int r;
826     int kernel_driver_detached = 0;
827 
828     // Detach OS driver (not possible for OS X, FreeBSD, and Windows)
829 #if !defined(__APPLE__) && !defined(_WIN32) && !defined(__CYGWIN__) && !defined(__FreeBSD__)
830     r = libusb_kernel_driver_active(aHandle, 0);
831     if (r < 0) {
832         log_error("libusb_kernel_driver_active error %d", r);
833         libusb_close(aHandle);
834         return r;
835     }
836 
837     if (r == 1) {
838         r = libusb_detach_kernel_driver(aHandle, 0);
839         if (r < 0) {
840             log_error("libusb_detach_kernel_driver error %d", r);
841             libusb_close(aHandle);
842             return r;
843         }
844         kernel_driver_detached = 1;
845     }
846     log_info("libusb_detach_kernel_driver");
847 #endif
848 
849     const int configuration = 1;
850     log_info("setting configuration %d...", configuration);
851     r = libusb_set_configuration(aHandle, configuration);
852     if (r < 0) {
853         log_error("Error libusb_set_configuration: %d", r);
854         if (kernel_driver_detached){
855             libusb_attach_kernel_driver(aHandle, 0);
856         }
857         libusb_close(aHandle);
858         return r;
859     }
860 
861     // reserve access to device
862     log_info("claiming interface 0...");
863     r = libusb_claim_interface(aHandle, 0);
864     if (r < 0) {
865         log_error("Error %d claiming interface 0", r);
866         if (kernel_driver_detached){
867             libusb_attach_kernel_driver(aHandle, 0);
868         }
869         libusb_close(aHandle);
870         return r;
871     }
872 
873 #ifdef ENABLE_SCO_OVER_HCI
874     // get endpoints from interface descriptor
875     struct libusb_config_descriptor *config_descriptor;
876     r = libusb_get_active_config_descriptor(device, &config_descriptor);
877     if (r >= 0){
878         int num_interfaces = config_descriptor->bNumInterfaces;
879         if (num_interfaces > 1) {
880             r = libusb_claim_interface(aHandle, 1);
881             if (r < 0) {
882                 log_error("Error %d claiming interface 1: - disabling SCO over HCI", r);
883             } else {
884                 sco_enabled = 1;
885             }
886         } else {
887             log_info("Device has only on interface, disabling SCO over HCI");
888         }
889     }
890 #endif
891 
892     return 0;
893 }
894 
895 static libusb_device_handle * try_open_device(libusb_device * device){
896     int r;
897 
898     r = libusb_get_device_descriptor(device, &desc);
899     if (r < 0) {
900         log_error("libusb_get_device_descriptor failed!");
901         return NULL;
902     }
903     usb_vendor_id = desc.idVendor;
904     usb_product_id = desc.idProduct;
905 
906     libusb_device_handle * dev_handle;
907     r = libusb_open(device, &dev_handle);
908 
909     if (r < 0) {
910         log_error("libusb_open failed!");
911         dev_handle = NULL;
912         return NULL;
913     }
914 
915     log_info("libusb open %d, handle %p", r, dev_handle);
916 
917     // reset device (Not currently possible under FreeBSD 11.x/12.x due to usb framework)
918 #if !defined(__FreeBSD__)
919     r = libusb_reset_device(dev_handle);
920     if (r < 0) {
921         log_error("libusb_reset_device failed!");
922         libusb_close(dev_handle);
923         return NULL;
924     }
925 #endif
926     return dev_handle;
927 }
928 
929 #ifdef ENABLE_SCO_OVER_HCI
930 static int usb_sco_start(void){
931 
932     log_info("usb_sco_start");
933     if( sco_activated ) {
934         log_error("double sco start!");
935         return -1;
936     }
937     sco_activated = true;
938 
939     sco_state_machine_init();
940 
941     int alt_setting;
942     if (sco_voice_setting & 0x0020){
943         // 16-bit PCM
944         alt_setting = alt_setting_16_bit[sco_num_connections-1];
945     } else {
946         // 8-bit PCM or mSBC
947         alt_setting = alt_setting_8_bit[sco_num_connections-1];
948     }
949     // derive iso packet size from alt setting
950     iso_packet_size = iso_packet_size_for_alt_setting[alt_setting];
951 
952     log_info("Switching to setting %u on interface 1..", alt_setting);
953     int r = libusb_set_interface_alt_setting(handle, 1, alt_setting);
954     if (r < 0) {
955         log_error("Error setting alternative setting %u for interface 1: %s\n", alt_setting, libusb_error_name(r));
956         return r;
957     }
958 
959 #ifdef DEBUG
960     int in_flight = usb_transfer_list_in_flight( sco_transfer_list );
961     // there need to be at least SCO_IN_BUFFER_COUNT packets available to
962     // fill them in below
963     assert( in_flight <= SCO_OUT_BUFFER_COUNT );
964 #endif
965 
966     // incoming
967     int c;
968     for (c = 0 ; c < SCO_IN_BUFFER_COUNT ; c++) {
969 
970         struct libusb_transfer *transfer = usb_transfer_list_acquire( sco_transfer_list );
971         uint8_t *data = transfer->buffer;
972         void *user_data = transfer->user_data;
973 
974         // configure sco_in handlers
975         libusb_fill_iso_transfer(transfer, handle, sco_in_addr,
976                 data, NUM_ISO_PACKETS * iso_packet_size, NUM_ISO_PACKETS, async_callback, user_data, 0);
977         libusb_set_iso_packet_lengths(transfer, iso_packet_size);
978         r = libusb_submit_transfer(transfer);
979         if (r) {
980             log_error("Error submitting isochronous in transfer %d", r);
981             usb_close();
982             return r;
983         }
984     }
985     return 0;
986 }
987 
988 static void usb_sco_stop(void){
989 
990     log_info("usb_sco_stop");
991     sco_activated = false;
992 
993     usb_transfer_list_cancel( sco_transfer_list );
994 
995     log_info("Switching to setting %u on interface 1..", 0);
996     int r = libusb_set_interface_alt_setting(handle, 1, 0);
997     if (r < 0) {
998         log_error("Error setting alternative setting %u for interface 1: %s", 0, libusb_error_name(r));
999         return;
1000     }
1001 
1002     log_info("usb_sco_stop done");
1003 }
1004 #endif
1005 
1006 void pollfd_added_cb(int fd, short events, void *user_data);
1007 void pollfd_remove_cb(int fd, void *user_data);
1008 
1009 void pollfd_added_cb(int fd, short events, void *user_data) {
1010     UNUSED(events);
1011     UNUSED(user_data);
1012     log_error("add fd: %d", fd);
1013     assert(0);
1014 }
1015 
1016 void pollfd_remove_cb(int fd, void *user_data) {
1017     UNUSED(user_data);
1018     log_error("remove fd: %d", fd);
1019     assert(0);
1020 }
1021 
1022 static int usb_open(void){
1023     int r;
1024 
1025     if (usb_transport_open) return 0;
1026 
1027     // default endpoint addresses
1028     event_in_addr = 0x81; // EP1, IN interrupt
1029     acl_in_addr =   0x82; // EP2, IN bulk
1030     acl_out_addr =  0x02; // EP2, OUT bulk
1031     sco_in_addr  =  0x83; // EP3, IN isochronous
1032     sco_out_addr =  0x03; // EP3, OUT isochronous
1033 
1034     // USB init
1035     r = libusb_init(NULL);
1036     if (r < 0) return -1;
1037 
1038     libusb_state = LIB_USB_OPENED;
1039 
1040     // configure debug level
1041     libusb_set_debug(NULL, LIBUSB_LOG_LEVEL_WARNING);
1042 
1043     libusb_device * dev = NULL;
1044 
1045 #ifdef HAVE_USB_VENDOR_ID_AND_PRODUCT_ID
1046 
1047     // Use a specified device
1048     log_info("Want vend: %04x, prod: %04x", USB_VENDOR_ID, USB_PRODUCT_ID);
1049     handle = libusb_open_device_with_vid_pid(NULL, USB_VENDOR_ID, USB_PRODUCT_ID);
1050 
1051     if (!handle){
1052         log_error("libusb_open_device_with_vid_pid failed!");
1053         usb_close();
1054         return -1;
1055     }
1056     log_info("libusb open %d, handle %p", r, handle);
1057 
1058     r = prepare_device(handle);
1059     if (r < 0){
1060         usb_close();
1061         return -1;
1062     }
1063 
1064     dev = libusb_get_device(handle);
1065     r = scan_for_bt_endpoints(dev);
1066     if (r < 0){
1067         usb_close();
1068         return -1;
1069     }
1070 
1071     usb_vendor_id = USB_VENDOR_ID;
1072     usb_product_id = USB_PRODUCT_ID;
1073 
1074 #else
1075     // Scan system for an appropriate devices
1076     libusb_device **devs;
1077     ssize_t num_devices;
1078 
1079     log_info("Scanning for USB Bluetooth device");
1080     num_devices = libusb_get_device_list(NULL, &devs);
1081     if (num_devices < 0) {
1082         usb_close();
1083         return -1;
1084     }
1085 
1086     if (usb_path_len){
1087         int i;
1088         for (i=0;i<num_devices;i++){
1089             uint8_t port_numbers[USB_MAX_PATH_LEN];
1090             int len = libusb_get_port_numbers(devs[i], port_numbers, USB_MAX_PATH_LEN);
1091             if (len != usb_path_len) continue;
1092             if (memcmp(usb_path, port_numbers, len) == 0){
1093                 log_info("USB device found at specified path");
1094                 handle = try_open_device(devs[i]);
1095                 if (!handle) continue;
1096 
1097                 r = prepare_device(handle);
1098                 if (r < 0) {
1099                     handle = NULL;
1100                     continue;
1101                 }
1102 
1103                 dev = devs[i];
1104                 r = scan_for_bt_endpoints(dev);
1105                 if (r < 0) {
1106                     handle = NULL;
1107                     continue;
1108                 }
1109 
1110                 libusb_state = LIB_USB_INTERFACE_CLAIMED;
1111                 break;
1112             };
1113         }
1114         if (!handle){
1115             log_error("USB device with given path not found");
1116             return -1;
1117         }
1118     } else {
1119 
1120         int deviceIndex = -1;
1121         while (true){
1122             // look for next Bluetooth dongle
1123             deviceIndex = scan_for_bt_device(devs, deviceIndex+1);
1124             if (deviceIndex < 0) break;
1125 
1126             log_info("USB Bluetooth device found, index %u", deviceIndex);
1127 
1128             handle = try_open_device(devs[deviceIndex]);
1129             if (!handle) continue;
1130 
1131             r = prepare_device(handle);
1132             if (r < 0) {
1133                 handle = NULL;
1134                 continue;
1135             }
1136 
1137             dev = devs[deviceIndex];
1138             r = scan_for_bt_endpoints(dev);
1139             if (r < 0) {
1140                 handle = NULL;
1141                 continue;
1142             }
1143 
1144             libusb_state = LIB_USB_INTERFACE_CLAIMED;
1145             break;
1146         }
1147     }
1148 
1149     libusb_free_device_list(devs, 1);
1150 
1151     if (handle == 0){
1152         log_error("No USB Bluetooth device found");
1153         return -1;
1154     }
1155 
1156 #endif
1157 
1158     // allocate transfer handlers
1159     int c;
1160 
1161     default_transfer_list = usb_transfer_list_alloc(
1162             EVENT_OUT_BUFFER_COUNT+EVENT_IN_BUFFER_COUNT+ACL_IN_BUFFER_COUNT,
1163             0,
1164             LIBUSB_CONTROL_SETUP_SIZE + HCI_INCOMING_PRE_BUFFER_SIZE + HCI_ACL_BUFFER_SIZE ); // biggest packet ever to expect
1165 
1166 #ifdef ENABLE_SCO_OVER_HCI
1167     sco_transfer_list = usb_transfer_list_alloc(
1168             SCO_OUT_BUFFER_COUNT+SCO_IN_BUFFER_COUNT,
1169             NUM_ISO_PACKETS,
1170             SCO_PACKET_SIZE
1171             );
1172 #endif
1173 
1174     // TODO check for error
1175 
1176     libusb_state = LIB_USB_TRANSFERS_ALLOCATED;
1177 
1178     for (c = 0 ; c < EVENT_IN_BUFFER_COUNT ; c++) {
1179         struct libusb_transfer *transfer = usb_transfer_list_acquire( default_transfer_list );
1180         uint8_t *data = transfer->buffer;
1181         void *user_data = transfer->user_data;
1182         // configure event_in handlers
1183         libusb_fill_interrupt_transfer(transfer, handle, event_in_addr,
1184                 data, HCI_ACL_BUFFER_SIZE, async_callback, user_data, 0);
1185         r = libusb_submit_transfer(transfer);
1186         if (r) {
1187             log_error("Error submitting interrupt transfer %d", r);
1188             usb_close();
1189             return r;
1190         }
1191     }
1192 
1193     for (c = 0 ; c < ACL_IN_BUFFER_COUNT ; c++) {
1194         struct libusb_transfer *transfer = usb_transfer_list_acquire( default_transfer_list );
1195         usb_transfer_list_entry_t *transfer_meta_data = (usb_transfer_list_entry_t*)transfer->user_data;
1196         uint8_t *data = transfer_meta_data->data;
1197         void *user_data = transfer->user_data;
1198         // configure acl_in handlers
1199         libusb_fill_bulk_transfer(transfer, handle, acl_in_addr,
1200                 data + HCI_INCOMING_PRE_BUFFER_SIZE, HCI_ACL_BUFFER_SIZE, async_callback, user_data, 0) ;
1201         r = libusb_submit_transfer(transfer);
1202         if (r) {
1203             log_error("Error submitting bulk in transfer %d", r);
1204             usb_close();
1205             return r;
1206         }
1207 
1208      }
1209 
1210     // Check for pollfds functionality
1211     doing_pollfds = libusb_pollfds_handle_timeouts(NULL);
1212 
1213     libusb_set_pollfd_notifiers( NULL,  pollfd_added_cb, pollfd_remove_cb, NULL );
1214 
1215     if (doing_pollfds) {
1216         log_info("Async using pollfds:");
1217 
1218         const struct libusb_pollfd ** pollfd = libusb_get_pollfds(NULL);
1219         for (num_pollfds = 0 ; pollfd[num_pollfds] ; num_pollfds++);
1220         pollfd_data_sources = (btstack_data_source_t *)malloc(sizeof(btstack_data_source_t) * num_pollfds);
1221         if (!pollfd_data_sources){
1222             log_error("Cannot allocate data sources for pollfds");
1223             usb_close();
1224             return 1;
1225         }
1226         memset(pollfd_data_sources, 0, sizeof(btstack_data_source_t) * num_pollfds);
1227         for (r = 0 ; r < num_pollfds ; r++) {
1228             btstack_data_source_t *ds = &pollfd_data_sources[r];
1229             btstack_run_loop_set_data_source_fd(ds, pollfd[r]->fd);
1230             btstack_run_loop_set_data_source_handler(ds, &usb_process_ds);
1231             if( pollfd[r]->events & POLLIN )
1232                 btstack_run_loop_enable_data_source_callbacks(ds, DATA_SOURCE_CALLBACK_READ);
1233             else
1234                 btstack_run_loop_enable_data_source_callbacks(ds, DATA_SOURCE_CALLBACK_WRITE);
1235             btstack_run_loop_add_data_source(ds);
1236             log_info("%u: %p fd: %u, events %x", r, pollfd[r], pollfd[r]->fd, pollfd[r]->events);
1237         }
1238         libusb_free_pollfds(pollfd);
1239     } else {
1240         log_info("Async using timers:");
1241 
1242         usb_timer.process = usb_process_ts;
1243         btstack_run_loop_set_timer(&usb_timer, ASYNC_POLLING_INTERVAL_MS);
1244         btstack_run_loop_add_timer(&usb_timer);
1245         usb_timer_active = 1;
1246     }
1247 
1248     usb_transport_open = 1;
1249 
1250     hci_transport_h2_libusb_emit_usb_info();
1251 
1252     btstack_data_source_t *ds = &transport_response;
1253     btstack_run_loop_set_data_source_handler(ds, &usb_transport_response_ds);
1254     btstack_run_loop_enable_data_source_callbacks(ds, DATA_SOURCE_CALLBACK_POLL);
1255     btstack_run_loop_add_data_source(ds);
1256     return 0;
1257 }
1258 
1259 static int usb_close(void) {
1260     if (!usb_transport_open) return 0;
1261 
1262     log_info("usb_close");
1263 
1264     switch (libusb_state){
1265         case LIB_USB_CLOSED:
1266             break;
1267 
1268         case LIB_USB_TRANSFERS_ALLOCATED:
1269             libusb_state = LIB_USB_INTERFACE_CLAIMED;
1270 
1271             if(usb_timer_active) {
1272                 btstack_run_loop_remove_timer(&usb_timer);
1273                 usb_timer_active = 0;
1274             }
1275 
1276             if (doing_pollfds){
1277                 int r;
1278                 for (r = 0 ; r < num_pollfds ; r++) {
1279                     btstack_data_source_t *ds = &pollfd_data_sources[r];
1280                     btstack_run_loop_remove_data_source(ds);
1281                 }
1282                 free(pollfd_data_sources);
1283                 pollfd_data_sources = NULL;
1284                 num_pollfds = 0;
1285                 doing_pollfds = 0;
1286             }
1287 
1288             /* fall through */
1289 
1290         case LIB_USB_INTERFACE_CLAIMED:
1291             libusb_set_pollfd_notifiers( NULL, NULL, NULL, NULL );
1292             usb_transfer_list_cancel( default_transfer_list );
1293 #ifdef ENABLE_SCO_OVER_HCI
1294             usb_transfer_list_cancel( sco_transfer_list );
1295 #endif
1296 
1297             int in_flight_transfers = usb_transfer_list_in_flight( default_transfer_list );
1298 #ifdef ENABLE_SCO_OVER_HCI
1299             in_flight_transfers += usb_transfer_list_in_flight( sco_transfer_list );
1300 #endif
1301             while( in_flight_transfers > 0 ) {
1302                 struct timeval tv = { 0 };
1303                 libusb_handle_events_timeout(NULL, &tv);
1304 
1305                 in_flight_transfers = usb_transfer_list_in_flight( default_transfer_list );
1306 #ifdef ENABLE_SCO_OVER_HCI
1307                 in_flight_transfers += usb_transfer_list_in_flight( sco_transfer_list );
1308 #endif
1309             }
1310 
1311             usb_transfer_list_free( default_transfer_list );
1312 #ifdef ENABLE_SCO_OVER_HCI
1313             usb_transfer_list_free( sco_transfer_list );
1314             sco_enabled = 0;
1315 #endif
1316 
1317             // finally release interface
1318             libusb_release_interface(handle, 0);
1319 #ifdef ENABLE_SCO_OVER_HCI
1320             libusb_release_interface(handle, 1);
1321 #endif
1322             log_info("Libusb shutdown complete");
1323 
1324 			/* fall through */
1325 
1326         case LIB_USB_DEVICE_OPENDED:
1327             libusb_close(handle);
1328 
1329 			/* fall through */
1330 
1331         case LIB_USB_OPENED:
1332             libusb_exit(NULL);
1333             break;
1334 
1335 		default:
1336 			btstack_assert(false);
1337 			break;
1338     }
1339 
1340     libusb_state = LIB_USB_CLOSED;
1341     handle = NULL;
1342     usb_transport_open = 0;
1343 
1344     return 0;
1345 }
1346 
1347 static int acknowledge_count = 0;
1348 static void signal_acknowledge() {
1349     ++acknowledge_count;
1350     btstack_run_loop_poll_data_sources_from_irq();
1351 }
1352 
1353 static int sco_can_send_now_count = 0;
1354 static void signal_sco_can_send_now() {
1355     ++sco_can_send_now_count;
1356     btstack_run_loop_poll_data_sources_from_irq();
1357 }
1358 
1359 static void usb_transport_response_ds(btstack_data_source_t *ds, btstack_data_source_callback_type_t callback_type) {
1360     UNUSED(ds);
1361     UNUSED(callback_type);
1362 //    printf("%s packet sent: %d sco can send now: %d\n", __FUNCTION__, acknowledge_count, sco_can_send_now_count);
1363     for(; acknowledge_count>0; --acknowledge_count) {
1364         static const uint8_t event[] = { HCI_EVENT_TRANSPORT_PACKET_SENT, 0 };
1365         packet_handler(HCI_EVENT_PACKET, (uint8_t*)&event[0], sizeof(event));
1366     }
1367 
1368     for(; sco_can_send_now_count>0; --sco_can_send_now_count) {
1369         static const uint8_t event[] = { HCI_EVENT_SCO_CAN_SEND_NOW, 0 };
1370         packet_handler(HCI_EVENT_PACKET, (uint8_t*)&event[0], sizeof(event));
1371     }
1372 
1373 }
1374 
1375 static int usb_send_cmd_packet(uint8_t *packet, int size){
1376     int r;
1377 
1378     if (libusb_state != LIB_USB_TRANSFERS_ALLOCATED) return -1;
1379 //    printf("%s( %p, %d )\n", __FUNCTION__, packet, size );
1380 
1381     struct libusb_transfer *transfer = usb_transfer_list_acquire( default_transfer_list );
1382     uint8_t *data = transfer->buffer;
1383     void *user_data = transfer->user_data;
1384 
1385     // async
1386     libusb_fill_control_setup(data, LIBUSB_REQUEST_TYPE_CLASS | LIBUSB_RECIPIENT_INTERFACE, 0, 0, 0, size);
1387     memcpy(data + LIBUSB_CONTROL_SETUP_SIZE, packet, size);
1388 
1389     // prepare transfer
1390     libusb_fill_control_transfer(transfer, handle, data, async_callback, user_data, 0);
1391 
1392     // submit transfer
1393     assert( transfer->user_data != NULL );
1394     r = libusb_submit_transfer(transfer);
1395 
1396     if (r < 0) {
1397         log_error("Error submitting cmd transfer %d", r);
1398         return -1;
1399     }
1400 
1401     signal_acknowledge();
1402 
1403     return 0;
1404 }
1405 
1406 static int usb_send_acl_packet(uint8_t *packet, int size){
1407     int r;
1408 
1409     if (libusb_state != LIB_USB_TRANSFERS_ALLOCATED) return -1;
1410 //   printf("%s( %p, %d )\n", __FUNCTION__, packet, size );
1411     // log_info("usb_send_acl_packet enter, size %u", size);
1412 
1413     struct libusb_transfer *transfer = usb_transfer_list_acquire( default_transfer_list );
1414     uint8_t *data = transfer->buffer;
1415 
1416     // prepare transfer
1417     memcpy( data, packet, size );
1418     libusb_fill_bulk_transfer(transfer, handle, acl_out_addr, data, size,
1419         async_callback, transfer->user_data, 0);
1420 
1421     assert( transfer->user_data != NULL );
1422     r = libusb_submit_transfer(transfer);
1423 
1424     if (r < 0) {
1425         log_error("Error submitting acl transfer, %d", r);
1426         return -1;
1427     }
1428 
1429     signal_acknowledge();
1430 
1431     return 0;
1432 }
1433 
1434 static int usb_can_send_packet_now(uint8_t packet_type){
1435     switch (packet_type){
1436         case HCI_COMMAND_DATA_PACKET: {
1437             int ret = !usb_transfer_list_empty( default_transfer_list );
1438             if( !ret ) {
1439                 log_error("command transfers shouldn't be empty!");
1440             }
1441             return ret;
1442         }
1443         case HCI_ACL_DATA_PACKET: {
1444             int ret = !usb_transfer_list_empty( default_transfer_list );
1445             if( !ret ) {
1446                 log_error("acl transfers shouldn't be empty!");
1447             }
1448             return ret;
1449         }
1450 
1451 #ifdef ENABLE_SCO_OVER_HCI
1452         case HCI_SCO_DATA_PACKET: {
1453             if (!sco_enabled || !sco_activated) return 0;
1454             int ret = !usb_transfer_list_empty( sco_transfer_list );
1455             if( !ret ) {
1456                 log_error("sco transfers shouldn't be empty!");
1457             }
1458             return ret;
1459         }
1460 #endif
1461         default:
1462             return 0;
1463     }
1464 }
1465 
1466 static int usb_send_packet(uint8_t packet_type, uint8_t * packet, int size){
1467     switch (packet_type){
1468         case HCI_COMMAND_DATA_PACKET:
1469             return usb_send_cmd_packet(packet, size);
1470         case HCI_ACL_DATA_PACKET:
1471             return usb_send_acl_packet(packet, size);
1472 #ifdef ENABLE_SCO_OVER_HCI
1473         case HCI_SCO_DATA_PACKET:
1474             if (!sco_enabled) return -1;
1475             return usb_send_sco_packet(packet, size);
1476 #endif
1477         default:
1478             return -1;
1479     }
1480 }
1481 
1482 #ifdef ENABLE_SCO_OVER_HCI
1483 static void usb_set_sco_config(uint16_t voice_setting, int num_connections){
1484     if (!sco_enabled) return;
1485 
1486     log_info("usb_set_sco_config: voice settings 0x%04x, num connections %u", voice_setting, num_connections);
1487 
1488     if (num_connections != sco_num_connections){
1489         sco_voice_setting = voice_setting;
1490         if (sco_num_connections){
1491             usb_sco_stop();
1492         }
1493         sco_num_connections = num_connections;
1494         if (num_connections){
1495             usb_sco_start();
1496         }
1497     }
1498 }
1499 #endif
1500 
1501 static void usb_register_packet_handler(void (*handler)(uint8_t packet_type, uint8_t *packet, uint16_t size)){
1502     log_info("registering packet handler");
1503     packet_handler = handler;
1504 }
1505 
1506 static void dummy_handler(uint8_t packet_type, uint8_t *packet, uint16_t size){
1507     UNUSED(packet_type);
1508     UNUSED(packet);
1509     UNUSED(size);
1510 }
1511 
1512 // get usb singleton
1513 const hci_transport_t * hci_transport_usb_instance(void) {
1514     if (!hci_transport_usb) {
1515         hci_transport_usb = (hci_transport_t*) malloc( sizeof(hci_transport_t));
1516         memset(hci_transport_usb, 0, sizeof(hci_transport_t));
1517         hci_transport_usb->name                          = "H2_LIBUSB";
1518         hci_transport_usb->open                          = usb_open;
1519         hci_transport_usb->close                         = usb_close;
1520         hci_transport_usb->register_packet_handler       = usb_register_packet_handler;
1521         hci_transport_usb->can_send_packet_now           = usb_can_send_packet_now;
1522         hci_transport_usb->send_packet                   = usb_send_packet;
1523 #ifdef ENABLE_SCO_OVER_HCI
1524         hci_transport_usb->set_sco_config                = usb_set_sco_config;
1525 #endif
1526     }
1527     return hci_transport_usb;
1528 }
1529