xref: /btstack/platform/libusb/hci_transport_h2_libusb.c (revision 34de5f8b9a42e6e79c7a8d9ef99f12879375fa69)
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         if(( transfer->endpoint == sco_in_addr) || (transfer->endpoint == sco_out_addr)) {
448             usb_transfer_list_release( sco_transfer_list, transfer );
449         } else {
450             usb_transfer_list_release( default_transfer_list, transfer );
451         }
452     } else {
453         log_info("async_callback. not data -> resubmit transfer, endpoint %x, status %x, length %u", transfer->endpoint, transfer->status, transfer->actual_length);
454         // No usable data, just resubmit packet
455         r = libusb_submit_transfer(transfer);
456         if (r) {
457             log_error("Error re-submitting transfer %d", r);
458         }
459     }
460     // log_info("end async_callback");
461 }
462 
463 
464 #ifdef ENABLE_SCO_OVER_HCI
465 static int usb_send_sco_packet(uint8_t *packet, int size){
466     int r;
467 
468     if( !sco_activated ) {
469         log_error("sco send without beeing active!");
470         return -1;
471     }
472 
473     if (libusb_state != LIB_USB_TRANSFERS_ALLOCATED) return -1;
474 
475     struct libusb_transfer *transfer = usb_transfer_list_acquire( sco_transfer_list );
476     uint8_t *data = transfer->buffer;
477     void *user_data = transfer->user_data;
478 
479     // log_info("usb_send_acl_packet enter, size %u", size);
480 
481     // store packet in free slot
482     memcpy(data, packet, size);
483 
484     // setup transfer
485     // 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);
486     libusb_fill_iso_transfer(transfer, handle, sco_out_addr, data, NUM_ISO_PACKETS * iso_packet_size, NUM_ISO_PACKETS, async_callback, user_data, 0);
487     libusb_set_iso_packet_lengths(transfer, iso_packet_size);
488     r = libusb_submit_transfer(transfer);
489     if (r < 0) {
490         log_error("Error submitting sco transfer, %d", r);
491         return -1;
492     }
493 
494     // log_info("H2: queued packet at index %u, num active %u", tranfer_index, sco_out_transfers_active);
495     signal_acknowledge();
496 
497     if( !usb_transfer_list_empty( sco_transfer_list ) ) {
498         signal_sco_can_send_now();
499     }
500 
501     return 0;
502 }
503 
504 static void sco_state_machine_init(void){
505     sco_state = H2_W4_SCO_HEADER;
506     sco_read_pos = 0;
507     sco_bytes_to_read = 3;
508 }
509 
510 static void handle_isochronous_data(uint8_t * buffer, uint16_t size){
511     while (size){
512         if (size < sco_bytes_to_read){
513             // just store incomplete data
514             memcpy(&sco_buffer[sco_read_pos], buffer, size);
515             sco_read_pos      += size;
516             sco_bytes_to_read -= size;
517             return;
518         }
519         // copy requested data
520         memcpy(&sco_buffer[sco_read_pos], buffer, sco_bytes_to_read);
521         sco_read_pos += sco_bytes_to_read;
522         buffer       += sco_bytes_to_read;
523         size         -= sco_bytes_to_read;
524 
525         // chunk read successfully, next action
526         switch (sco_state){
527             case H2_W4_SCO_HEADER:
528                 sco_state = H2_W4_PAYLOAD;
529                 sco_bytes_to_read = sco_buffer[2];
530                 break;
531             case H2_W4_PAYLOAD:
532                 // packet complete
533                 packet_handler(HCI_SCO_DATA_PACKET, sco_buffer, sco_read_pos);
534                 sco_state_machine_init();
535                 break;
536 			default:
537 				btstack_assert(false);
538 				break;
539         }
540     }
541 }
542 #endif
543 
544 static void handle_completed_transfer(struct libusb_transfer *transfer){
545 
546     int resubmit = 0;
547     assert(transfer->user_data != NULL );
548     if (transfer->endpoint == event_in_addr) {
549         packet_handler(HCI_EVENT_PACKET, transfer->buffer, transfer->actual_length);
550         resubmit = 1;
551     } else if (transfer->endpoint == acl_in_addr) {
552         // log_info("-> acl");
553         packet_handler(HCI_ACL_DATA_PACKET, transfer->buffer, transfer->actual_length);
554         resubmit = 1;
555     } else if (transfer->endpoint == 0){
556         // log_info("command done, size %u", transfer->actual_length);
557 //        printf("%s cmd release\n", __FUNCTION__ );
558         usb_transfer_list_release( default_transfer_list, transfer );
559     } else if (transfer->endpoint == acl_out_addr){
560         // log_info("acl out done, size %u", transfer->actual_length);
561 //        printf("%s acl release\n", __FUNCTION__ );
562         usb_transfer_list_release( default_transfer_list, transfer );
563 #ifdef ENABLE_SCO_OVER_HCI
564     } else if (transfer->endpoint == sco_in_addr) {
565         // log_info("handle_completed_transfer for SCO IN! num packets %u", transfer->NUM_ISO_PACKETS);
566 
567         // give the transfer back to the pool, without resubmiting
568         if( !sco_activated ) {
569             usb_transfer_list_release( sco_transfer_list, transfer );
570             return;
571         }
572 
573         int i;
574         for (i = 0; i < transfer->num_iso_packets; i++) {
575             struct libusb_iso_packet_descriptor *pack = &transfer->iso_packet_desc[i];
576             if (pack->status != LIBUSB_TRANSFER_COMPLETED) {
577                 log_error("Error: pack %u status %d\n", i, pack->status);
578                 continue;
579             }
580             if (!pack->actual_length) continue;
581             uint8_t * data = libusb_get_iso_packet_buffer_simple(transfer, i);
582             handle_isochronous_data(data, pack->actual_length);
583         }
584         resubmit = 1;
585     } else if (transfer->endpoint == sco_out_addr){
586         int i;
587         for (i = 0; i < transfer->num_iso_packets; i++) {
588             struct libusb_iso_packet_descriptor *pack = &transfer->iso_packet_desc[i];
589             if (pack->status != LIBUSB_TRANSFER_COMPLETED) {
590                 log_error("Error: pack %u status %d\n", i, pack->status);
591             }
592         }
593         usb_transfer_list_release( sco_transfer_list, transfer );
594         if( !sco_activated ) {
595             return;
596         }
597         // log_info("sco out done, {{ %u/%u (%x)}, { %u/%u (%x)}, { %u/%u (%x)}}",
598         //     transfer->iso_packet_desc[0].actual_length, transfer->iso_packet_desc[0].length, transfer->iso_packet_desc[0].status,
599         //     transfer->iso_packet_desc[1].actual_length, transfer->iso_packet_desc[1].length, transfer->iso_packet_desc[1].status,
600         //     transfer->iso_packet_desc[2].actual_length, transfer->iso_packet_desc[2].length, transfer->iso_packet_desc[2].status);
601         // notify upper layer if there's space for new SCO packets
602 
603         if (!usb_transfer_list_empty(sco_transfer_list)) {
604             signal_sco_can_send_now();
605         }
606         // log_info("H2: sco out complete, num active num active %u", sco_out_transfers_active);
607 #endif
608     } else {
609         log_info("usb_process_ds endpoint unknown %x", transfer->endpoint);
610     }
611 
612     if (libusb_state != LIB_USB_TRANSFERS_ALLOCATED) return;
613 
614     if (resubmit){
615         // Re-submit transfer
616         int r = libusb_submit_transfer(transfer);
617         if (r) {
618             log_error("Error re-submitting transfer %d", r);
619         }
620     }
621 }
622 
623 void usb_handle_pending_events(void);
624 void usb_handle_pending_events(void) {
625     struct timeval tv = { 0 };
626     libusb_handle_events_timeout_completed(NULL, &tv, NULL);
627 }
628 
629 static void usb_process_ds(btstack_data_source_t *ds, btstack_data_source_callback_type_t callback_type) {
630 
631     UNUSED(ds);
632     UNUSED(callback_type);
633 
634    if (libusb_state != LIB_USB_TRANSFERS_ALLOCATED) return;
635 
636     // log_info("begin usb_process_ds");
637     // always handling an event as we're called when data is ready
638     usb_handle_pending_events();
639 
640     // Handle any packet in the order that they were received
641     while (!list_empty(&handle_packet_list)) {
642         // log_info("handle packet %p, endpoint %x, status %x", handle_packet, handle_packet->endpoint, handle_packet->status);
643 
644         // pop next transfer
645         usb_transfer_list_entry_t *current = (usb_transfer_list_entry_t*)list_pop_front( &handle_packet_list );
646 
647         // handle transfer
648         handle_completed_transfer(current->t);
649 
650         // handle case where libusb_close might be called by hci packet handler
651         if (libusb_state != LIB_USB_TRANSFERS_ALLOCATED) return;
652     }
653     // log_info("end usb_process_ds");
654 }
655 
656 static void usb_process_ts(btstack_timer_source_t *timer) {
657 
658     UNUSED(timer);
659 
660     // log_info("in usb_process_ts");
661 
662     // timer is deactive, when timer callback gets called
663     usb_timer_active = 0;
664 
665     if (libusb_state != LIB_USB_TRANSFERS_ALLOCATED) return;
666 
667     // actually handled the packet in the pollfds function
668     usb_process_ds((struct btstack_data_source *) NULL, DATA_SOURCE_CALLBACK_READ);
669 
670     // Get the amount of time until next event is due
671     long msec = ASYNC_POLLING_INTERVAL_MS;
672 
673     // Activate timer
674     btstack_run_loop_set_timer(&usb_timer, msec);
675     btstack_run_loop_add_timer(&usb_timer);
676     usb_timer_active = 1;
677 
678     return;
679 }
680 
681 
682 static int scan_for_bt_endpoints(libusb_device *dev) {
683     int r;
684 
685     event_in_addr = 0;
686     acl_in_addr = 0;
687     acl_out_addr = 0;
688     sco_out_addr = 0;
689     sco_in_addr = 0;
690 
691     // get endpoints from interface descriptor
692     struct libusb_config_descriptor *config_descriptor;
693     r = libusb_get_active_config_descriptor(dev, &config_descriptor);
694     if (r < 0) return r;
695 
696     int num_interfaces = config_descriptor->bNumInterfaces;
697     log_info("active configuration has %u interfaces", num_interfaces);
698 
699     int i;
700     for (i = 0; i < num_interfaces ; i++){
701         const struct libusb_interface *interface = &config_descriptor->interface[i];
702         const struct libusb_interface_descriptor * interface_descriptor = interface->altsetting;
703         log_info("interface %u: %u endpoints", i, interface_descriptor->bNumEndpoints);
704 
705         const struct libusb_endpoint_descriptor *endpoint = interface_descriptor->endpoint;
706 
707         for (r=0;r<interface_descriptor->bNumEndpoints;r++,endpoint++){
708             log_info("- endpoint %x, attributes %x", endpoint->bEndpointAddress, endpoint->bmAttributes);
709 
710             switch (endpoint->bmAttributes & 0x3){
711                 case LIBUSB_TRANSFER_TYPE_INTERRUPT:
712                     if (event_in_addr) continue;
713                     event_in_addr = endpoint->bEndpointAddress;
714                     log_info("-> using 0x%2.2X for HCI Events", event_in_addr);
715                     break;
716                 case LIBUSB_TRANSFER_TYPE_BULK:
717                     if (endpoint->bEndpointAddress & 0x80) {
718                         if (acl_in_addr) continue;
719                         acl_in_addr = endpoint->bEndpointAddress;
720                         log_info("-> using 0x%2.2X for ACL Data In", acl_in_addr);
721                     } else {
722                         if (acl_out_addr) continue;
723                         acl_out_addr = endpoint->bEndpointAddress;
724                         log_info("-> using 0x%2.2X for ACL Data Out", acl_out_addr);
725                     }
726                     break;
727                 case LIBUSB_TRANSFER_TYPE_ISOCHRONOUS:
728                     if (endpoint->bEndpointAddress & 0x80) {
729                         if (sco_in_addr) continue;
730                         sco_in_addr = endpoint->bEndpointAddress;
731                         log_info("-> using 0x%2.2X for SCO Data In", sco_in_addr);
732                     } else {
733                         if (sco_out_addr) continue;
734                         sco_out_addr = endpoint->bEndpointAddress;
735                         log_info("-> using 0x%2.2X for SCO Data Out", sco_out_addr);
736                     }
737                     break;
738                 default:
739                     break;
740             }
741         }
742     }
743     libusb_free_config_descriptor(config_descriptor);
744     return 0;
745 }
746 
747 #ifndef HAVE_USB_VENDOR_ID_AND_PRODUCT_ID
748 
749 // list of known devices, using VendorID/ProductID tuples
750 static const uint16_t known_bluetooth_devices[] = {
751     // BCM20702A0 - DeLOCK Bluetooth 4.0
752     0x0a5c, 0x21e8,
753     // BCM20702A0 - Asus BT400
754     0x0b05, 0x17cb,
755     // BCM20702B0 - Generic USB Detuned Class 1 @ 20 MHz
756     0x0a5c, 0x22be,
757     // nRF5x Zephyr USB HCI, e.g nRF52840-PCA10056
758     0x2fe3, 0x0100,
759     0x2fe3, 0x000b,
760 };
761 
762 static int num_known_devices = sizeof(known_bluetooth_devices) / sizeof(uint16_t) / 2;
763 
764 static int is_known_bt_device(uint16_t vendor_id, uint16_t product_id){
765     int i;
766     for (i=0; i<num_known_devices; i++){
767         if (known_bluetooth_devices[i*2] == vendor_id && known_bluetooth_devices[i*2+1] == product_id){
768             return 1;
769         }
770     }
771     btstack_linked_list_iterator_t it;
772     btstack_linked_list_iterator_init(&it, &usb_knwon_devices);
773     while (btstack_linked_list_iterator_has_next(&it)) {
774         usb_known_device_t * device = (usb_known_device_t *) btstack_linked_list_iterator_next(&it);
775         if (device->vendor_id != vendor_id) continue;
776         if (device->product_id != product_id) continue;
777         return 1;
778     }
779     return 0;
780 }
781 
782 // returns index of found device or -1
783 static int scan_for_bt_device(libusb_device **devs, int start_index) {
784     int i;
785     for (i = start_index; devs[i] ; i++){
786         libusb_device * dev = devs[i];
787         int r = libusb_get_device_descriptor(dev, &desc);
788         if (r < 0) {
789             log_error("failed to get device descriptor");
790             return 0;
791         }
792 
793         log_info("%04x:%04x (bus %d, device %d) - class %x subclass %x protocol %x ",
794                desc.idVendor, desc.idProduct,
795                libusb_get_bus_number(dev), libusb_get_device_address(dev),
796                desc.bDeviceClass, desc.bDeviceSubClass, desc.bDeviceProtocol);
797 
798         // Detect USB Dongle based Class, Subclass, and Protocol
799         // The class code (bDeviceClass) is 0xE0 – Wireless Controller.
800         // The SubClass code (bDeviceSubClass) is 0x01 – RF Controller.
801         // The Protocol code (bDeviceProtocol) is 0x01 – Bluetooth programming.
802         if (desc.bDeviceClass == 0xE0 && desc.bDeviceSubClass == 0x01 && desc.bDeviceProtocol == 0x01) {
803             return i;
804         }
805 
806         // Detect USB Dongle based on whitelist
807         if (is_known_bt_device(desc.idVendor, desc.idProduct)) {
808             return i;
809         }
810     }
811     return -1;
812 }
813 #endif
814 
815 static int prepare_device(libusb_device_handle * aHandle){
816 
817     // get device path
818     libusb_device * device = libusb_get_device(aHandle);
819     usb_path_len = libusb_get_port_numbers(device, usb_path, USB_MAX_PATH_LEN);
820 
821     int r;
822     int kernel_driver_detached = 0;
823 
824     // Detach OS driver (not possible for OS X, FreeBSD, and Windows)
825 #if !defined(__APPLE__) && !defined(_WIN32) && !defined(__CYGWIN__) && !defined(__FreeBSD__)
826     r = libusb_kernel_driver_active(aHandle, 0);
827     if (r < 0) {
828         log_error("libusb_kernel_driver_active error %d", r);
829         libusb_close(aHandle);
830         return r;
831     }
832 
833     if (r == 1) {
834         r = libusb_detach_kernel_driver(aHandle, 0);
835         if (r < 0) {
836             log_error("libusb_detach_kernel_driver error %d", r);
837             libusb_close(aHandle);
838             return r;
839         }
840         kernel_driver_detached = 1;
841     }
842     log_info("libusb_detach_kernel_driver");
843 #endif
844 
845     const int configuration = 1;
846     log_info("setting configuration %d...", configuration);
847     r = libusb_set_configuration(aHandle, configuration);
848     if (r < 0) {
849         log_error("Error libusb_set_configuration: %d", r);
850         if (kernel_driver_detached){
851             libusb_attach_kernel_driver(aHandle, 0);
852         }
853         libusb_close(aHandle);
854         return r;
855     }
856 
857     // reserve access to device
858     log_info("claiming interface 0...");
859     r = libusb_claim_interface(aHandle, 0);
860     if (r < 0) {
861         log_error("Error %d claiming interface 0", r);
862         if (kernel_driver_detached){
863             libusb_attach_kernel_driver(aHandle, 0);
864         }
865         libusb_close(aHandle);
866         return r;
867     }
868 
869 #ifdef ENABLE_SCO_OVER_HCI
870     // get endpoints from interface descriptor
871     struct libusb_config_descriptor *config_descriptor;
872     r = libusb_get_active_config_descriptor(device, &config_descriptor);
873     if (r >= 0){
874         int num_interfaces = config_descriptor->bNumInterfaces;
875         if (num_interfaces > 1) {
876             r = libusb_claim_interface(aHandle, 1);
877             if (r < 0) {
878                 log_error("Error %d claiming interface 1: - disabling SCO over HCI", r);
879             } else {
880                 sco_enabled = 1;
881             }
882         } else {
883             log_info("Device has only on interface, disabling SCO over HCI");
884         }
885     }
886 #endif
887 
888     return 0;
889 }
890 
891 static libusb_device_handle * try_open_device(libusb_device * device){
892     int r;
893 
894     r = libusb_get_device_descriptor(device, &desc);
895     if (r < 0) {
896         log_error("libusb_get_device_descriptor failed!");
897         return NULL;
898     }
899     usb_vendor_id = desc.idVendor;
900     usb_product_id = desc.idProduct;
901 
902     libusb_device_handle * dev_handle;
903     r = libusb_open(device, &dev_handle);
904 
905     if (r < 0) {
906         log_error("libusb_open failed!");
907         dev_handle = NULL;
908         return NULL;
909     }
910 
911     log_info("libusb open %d, handle %p", r, dev_handle);
912 
913     // reset device (Not currently possible under FreeBSD 11.x/12.x due to usb framework)
914 #if !defined(__FreeBSD__)
915     r = libusb_reset_device(dev_handle);
916     if (r < 0) {
917         log_error("libusb_reset_device failed!");
918         libusb_close(dev_handle);
919         return NULL;
920     }
921 #endif
922     return dev_handle;
923 }
924 
925 #ifdef ENABLE_SCO_OVER_HCI
926 static int usb_sco_start(void){
927 
928     log_info("usb_sco_start");
929     if( sco_activated ) {
930         log_error("double sco start!");
931         return -1;
932     }
933     sco_activated = true;
934 
935     sco_state_machine_init();
936 
937     int alt_setting;
938     if (sco_voice_setting & 0x0020){
939         // 16-bit PCM
940         alt_setting = alt_setting_16_bit[sco_num_connections-1];
941     } else {
942         // 8-bit PCM or mSBC
943         alt_setting = alt_setting_8_bit[sco_num_connections-1];
944     }
945     // derive iso packet size from alt setting
946     iso_packet_size = iso_packet_size_for_alt_setting[alt_setting];
947 
948     log_info("Switching to setting %u on interface 1..", alt_setting);
949     int r = libusb_set_interface_alt_setting(handle, 1, alt_setting);
950     if (r < 0) {
951         log_error("Error setting alternative setting %u for interface 1: %s\n", alt_setting, libusb_error_name(r));
952         return r;
953     }
954 
955 #ifdef DEBUG
956     int in_flight = usb_transfer_list_in_flight( sco_transfer_list );
957     // there need to be at least SCO_IN_BUFFER_COUNT packets available to
958     // fill them in below
959     assert( in_flight <= SCO_OUT_BUFFER_COUNT );
960 #endif
961 
962     // incoming
963     int c;
964     for (c = 0 ; c < SCO_IN_BUFFER_COUNT ; c++) {
965 
966         struct libusb_transfer *transfer = usb_transfer_list_acquire( sco_transfer_list );
967         uint8_t *data = transfer->buffer;
968         void *user_data = transfer->user_data;
969 
970         // configure sco_in handlers
971         libusb_fill_iso_transfer(transfer, handle, sco_in_addr,
972                 data, NUM_ISO_PACKETS * iso_packet_size, NUM_ISO_PACKETS, async_callback, user_data, 0);
973         libusb_set_iso_packet_lengths(transfer, iso_packet_size);
974         r = libusb_submit_transfer(transfer);
975         if (r) {
976             log_error("Error submitting isochronous in transfer %d", r);
977             usb_close();
978             return r;
979         }
980     }
981     return 0;
982 }
983 
984 static void usb_sco_stop(void){
985 
986     log_info("usb_sco_stop");
987     sco_activated = false;
988 
989     usb_transfer_list_cancel( sco_transfer_list );
990 
991     log_info("Switching to setting %u on interface 1..", 0);
992     int r = libusb_set_interface_alt_setting(handle, 1, 0);
993     if (r < 0) {
994         log_error("Error setting alternative setting %u for interface 1: %s", 0, libusb_error_name(r));
995         return;
996     }
997 
998     log_info("usb_sco_stop done");
999 }
1000 #endif
1001 
1002 void pollfd_added_cb(int fd, short events, void *user_data);
1003 void pollfd_remove_cb(int fd, void *user_data);
1004 
1005 void pollfd_added_cb(int fd, short events, void *user_data) {
1006     UNUSED(events);
1007     UNUSED(user_data);
1008     log_error("add fd: %d", fd);
1009     assert(0);
1010 }
1011 
1012 void pollfd_remove_cb(int fd, void *user_data) {
1013     UNUSED(user_data);
1014     log_error("remove fd: %d", fd);
1015     assert(0);
1016 }
1017 
1018 static int usb_open(void){
1019     int r;
1020 
1021     if (usb_transport_open) return 0;
1022 
1023     // default endpoint addresses
1024     event_in_addr = 0x81; // EP1, IN interrupt
1025     acl_in_addr =   0x82; // EP2, IN bulk
1026     acl_out_addr =  0x02; // EP2, OUT bulk
1027     sco_in_addr  =  0x83; // EP3, IN isochronous
1028     sco_out_addr =  0x03; // EP3, OUT isochronous
1029 
1030     // USB init
1031     r = libusb_init(NULL);
1032     if (r < 0) return -1;
1033 
1034     libusb_state = LIB_USB_OPENED;
1035 
1036     // configure debug level
1037     libusb_set_debug(NULL, LIBUSB_LOG_LEVEL_WARNING);
1038 
1039     libusb_device * dev = NULL;
1040 
1041 #ifdef HAVE_USB_VENDOR_ID_AND_PRODUCT_ID
1042 
1043     // Use a specified device
1044     log_info("Want vend: %04x, prod: %04x", USB_VENDOR_ID, USB_PRODUCT_ID);
1045     handle = libusb_open_device_with_vid_pid(NULL, USB_VENDOR_ID, USB_PRODUCT_ID);
1046 
1047     if (!handle){
1048         log_error("libusb_open_device_with_vid_pid failed!");
1049         usb_close();
1050         return -1;
1051     }
1052     log_info("libusb open %d, handle %p", r, handle);
1053 
1054     r = prepare_device(handle);
1055     if (r < 0){
1056         usb_close();
1057         return -1;
1058     }
1059 
1060     dev = libusb_get_device(handle);
1061     r = scan_for_bt_endpoints(dev);
1062     if (r < 0){
1063         usb_close();
1064         return -1;
1065     }
1066 
1067     usb_vendor_id = USB_VENDOR_ID;
1068     usb_product_id = USB_PRODUCT_ID;
1069 
1070 #else
1071     // Scan system for an appropriate devices
1072     libusb_device **devs;
1073     ssize_t num_devices;
1074 
1075     log_info("Scanning for USB Bluetooth device");
1076     num_devices = libusb_get_device_list(NULL, &devs);
1077     if (num_devices < 0) {
1078         usb_close();
1079         return -1;
1080     }
1081 
1082     if (usb_path_len){
1083         int i;
1084         for (i=0;i<num_devices;i++){
1085             uint8_t port_numbers[USB_MAX_PATH_LEN];
1086             int len = libusb_get_port_numbers(devs[i], port_numbers, USB_MAX_PATH_LEN);
1087             if (len != usb_path_len) continue;
1088             if (memcmp(usb_path, port_numbers, len) == 0){
1089                 log_info("USB device found at specified path");
1090                 handle = try_open_device(devs[i]);
1091                 if (!handle) continue;
1092 
1093                 r = prepare_device(handle);
1094                 if (r < 0) {
1095                     handle = NULL;
1096                     continue;
1097                 }
1098 
1099                 dev = devs[i];
1100                 r = scan_for_bt_endpoints(dev);
1101                 if (r < 0) {
1102                     handle = NULL;
1103                     continue;
1104                 }
1105 
1106                 libusb_state = LIB_USB_INTERFACE_CLAIMED;
1107                 break;
1108             };
1109         }
1110         if (!handle){
1111             log_error("USB device with given path not found");
1112             return -1;
1113         }
1114     } else {
1115 
1116         int deviceIndex = -1;
1117         while (true){
1118             // look for next Bluetooth dongle
1119             deviceIndex = scan_for_bt_device(devs, deviceIndex+1);
1120             if (deviceIndex < 0) break;
1121 
1122             log_info("USB Bluetooth device found, index %u", deviceIndex);
1123 
1124             handle = try_open_device(devs[deviceIndex]);
1125             if (!handle) continue;
1126 
1127             r = prepare_device(handle);
1128             if (r < 0) {
1129                 handle = NULL;
1130                 continue;
1131             }
1132 
1133             dev = devs[deviceIndex];
1134             r = scan_for_bt_endpoints(dev);
1135             if (r < 0) {
1136                 handle = NULL;
1137                 continue;
1138             }
1139 
1140             libusb_state = LIB_USB_INTERFACE_CLAIMED;
1141             break;
1142         }
1143     }
1144 
1145     libusb_free_device_list(devs, 1);
1146 
1147     if (handle == 0){
1148         log_error("No USB Bluetooth device found");
1149         return -1;
1150     }
1151 
1152 #endif
1153 
1154     // allocate transfer handlers
1155     int c;
1156 
1157     default_transfer_list = usb_transfer_list_alloc(
1158             EVENT_OUT_BUFFER_COUNT+EVENT_IN_BUFFER_COUNT+ACL_IN_BUFFER_COUNT,
1159             0,
1160             LIBUSB_CONTROL_SETUP_SIZE + HCI_INCOMING_PRE_BUFFER_SIZE + HCI_ACL_BUFFER_SIZE ); // biggest packet ever to expect
1161 
1162 #ifdef ENABLE_SCO_OVER_HCI
1163     sco_transfer_list = usb_transfer_list_alloc(
1164             SCO_OUT_BUFFER_COUNT+SCO_IN_BUFFER_COUNT,
1165             NUM_ISO_PACKETS,
1166             SCO_PACKET_SIZE
1167             );
1168 #endif
1169 
1170     // TODO check for error
1171 
1172     libusb_state = LIB_USB_TRANSFERS_ALLOCATED;
1173 
1174     for (c = 0 ; c < EVENT_IN_BUFFER_COUNT ; c++) {
1175         struct libusb_transfer *transfer = usb_transfer_list_acquire( default_transfer_list );
1176         uint8_t *data = transfer->buffer;
1177         void *user_data = transfer->user_data;
1178         // configure event_in handlers
1179         libusb_fill_interrupt_transfer(transfer, handle, event_in_addr,
1180                 data, HCI_ACL_BUFFER_SIZE, async_callback, user_data, 0);
1181         r = libusb_submit_transfer(transfer);
1182         if (r) {
1183             log_error("Error submitting interrupt transfer %d", r);
1184             usb_close();
1185             return r;
1186         }
1187     }
1188 
1189     for (c = 0 ; c < ACL_IN_BUFFER_COUNT ; c++) {
1190         struct libusb_transfer *transfer = usb_transfer_list_acquire( default_transfer_list );
1191         usb_transfer_list_entry_t *transfer_meta_data = (usb_transfer_list_entry_t*)transfer->user_data;
1192         uint8_t *data = transfer_meta_data->data;
1193         void *user_data = transfer->user_data;
1194         // configure acl_in handlers
1195         libusb_fill_bulk_transfer(transfer, handle, acl_in_addr,
1196                 data + HCI_INCOMING_PRE_BUFFER_SIZE, HCI_ACL_BUFFER_SIZE, async_callback, user_data, 0) ;
1197         r = libusb_submit_transfer(transfer);
1198         if (r) {
1199             log_error("Error submitting bulk in transfer %d", r);
1200             usb_close();
1201             return r;
1202         }
1203 
1204      }
1205 
1206     // Check for pollfds functionality
1207     doing_pollfds = libusb_pollfds_handle_timeouts(NULL);
1208 
1209     libusb_set_pollfd_notifiers( NULL,  pollfd_added_cb, pollfd_remove_cb, NULL );
1210 
1211     if (doing_pollfds) {
1212         log_info("Async using pollfds:");
1213 
1214         const struct libusb_pollfd ** pollfd = libusb_get_pollfds(NULL);
1215         for (num_pollfds = 0 ; pollfd[num_pollfds] ; num_pollfds++);
1216         pollfd_data_sources = (btstack_data_source_t *)malloc(sizeof(btstack_data_source_t) * num_pollfds);
1217         if (!pollfd_data_sources){
1218             log_error("Cannot allocate data sources for pollfds");
1219             usb_close();
1220             return 1;
1221         }
1222         memset(pollfd_data_sources, 0, sizeof(btstack_data_source_t) * num_pollfds);
1223         for (r = 0 ; r < num_pollfds ; r++) {
1224             btstack_data_source_t *ds = &pollfd_data_sources[r];
1225             btstack_run_loop_set_data_source_fd(ds, pollfd[r]->fd);
1226             btstack_run_loop_set_data_source_handler(ds, &usb_process_ds);
1227             if( pollfd[r]->events & POLLIN )
1228                 btstack_run_loop_enable_data_source_callbacks(ds, DATA_SOURCE_CALLBACK_READ);
1229             else
1230                 btstack_run_loop_enable_data_source_callbacks(ds, DATA_SOURCE_CALLBACK_WRITE);
1231             btstack_run_loop_add_data_source(ds);
1232             log_info("%u: %p fd: %u, events %x", r, pollfd[r], pollfd[r]->fd, pollfd[r]->events);
1233         }
1234         libusb_free_pollfds(pollfd);
1235     } else {
1236         log_info("Async using timers:");
1237 
1238         usb_timer.process = usb_process_ts;
1239         btstack_run_loop_set_timer(&usb_timer, ASYNC_POLLING_INTERVAL_MS);
1240         btstack_run_loop_add_timer(&usb_timer);
1241         usb_timer_active = 1;
1242     }
1243 
1244     usb_transport_open = 1;
1245 
1246     hci_transport_h2_libusb_emit_usb_info();
1247 
1248     btstack_data_source_t *ds = &transport_response;
1249     btstack_run_loop_set_data_source_handler(ds, &usb_transport_response_ds);
1250     btstack_run_loop_enable_data_source_callbacks(ds, DATA_SOURCE_CALLBACK_POLL);
1251     btstack_run_loop_add_data_source(ds);
1252     return 0;
1253 }
1254 
1255 static int usb_close(void) {
1256     if (!usb_transport_open) return 0;
1257 
1258     log_info("usb_close");
1259 
1260     switch (libusb_state){
1261         case LIB_USB_CLOSED:
1262             break;
1263 
1264         case LIB_USB_TRANSFERS_ALLOCATED:
1265             libusb_state = LIB_USB_INTERFACE_CLAIMED;
1266 
1267             if(usb_timer_active) {
1268                 btstack_run_loop_remove_timer(&usb_timer);
1269                 usb_timer_active = 0;
1270             }
1271 
1272             if (doing_pollfds){
1273                 int r;
1274                 for (r = 0 ; r < num_pollfds ; r++) {
1275                     btstack_data_source_t *ds = &pollfd_data_sources[r];
1276                     btstack_run_loop_remove_data_source(ds);
1277                 }
1278                 free(pollfd_data_sources);
1279                 pollfd_data_sources = NULL;
1280                 num_pollfds = 0;
1281                 doing_pollfds = 0;
1282             }
1283 
1284             /* fall through */
1285 
1286         case LIB_USB_INTERFACE_CLAIMED:
1287             libusb_set_pollfd_notifiers( NULL, NULL, NULL, NULL );
1288             usb_transfer_list_cancel( default_transfer_list );
1289 #ifdef ENABLE_SCO_OVER_HCI
1290             usb_transfer_list_cancel( sco_transfer_list );
1291 #endif
1292 
1293             int in_flight_transfers = usb_transfer_list_in_flight( default_transfer_list );
1294 #ifdef ENABLE_SCO_OVER_HCI
1295             in_flight_transfers += usb_transfer_list_in_flight( sco_transfer_list );
1296 #endif
1297             while( in_flight_transfers > 0 ) {
1298                 struct timeval tv = { 0 };
1299                 libusb_handle_events_timeout(NULL, &tv);
1300 
1301                 in_flight_transfers = usb_transfer_list_in_flight( default_transfer_list );
1302 #ifdef ENABLE_SCO_OVER_HCI
1303                 in_flight_transfers += usb_transfer_list_in_flight( sco_transfer_list );
1304 #endif
1305             }
1306 
1307             usb_transfer_list_free( default_transfer_list );
1308 #ifdef ENABLE_SCO_OVER_HCI
1309             usb_transfer_list_free( sco_transfer_list );
1310             sco_enabled = 0;
1311 #endif
1312 
1313             // finally release interface
1314             libusb_release_interface(handle, 0);
1315 #ifdef ENABLE_SCO_OVER_HCI
1316             libusb_release_interface(handle, 1);
1317 #endif
1318             log_info("Libusb shutdown complete");
1319 
1320 			/* fall through */
1321 
1322         case LIB_USB_DEVICE_OPENDED:
1323             libusb_close(handle);
1324 
1325 			/* fall through */
1326 
1327         case LIB_USB_OPENED:
1328             libusb_exit(NULL);
1329             break;
1330 
1331 		default:
1332 			btstack_assert(false);
1333 			break;
1334     }
1335 
1336     libusb_state = LIB_USB_CLOSED;
1337     handle = NULL;
1338     usb_transport_open = 0;
1339 
1340     return 0;
1341 }
1342 
1343 static int acknowledge_count = 0;
1344 static void signal_acknowledge() {
1345     ++acknowledge_count;
1346     btstack_run_loop_poll_data_sources_from_irq();
1347 }
1348 
1349 static int sco_can_send_now_count = 0;
1350 static void signal_sco_can_send_now() {
1351     ++sco_can_send_now_count;
1352     btstack_run_loop_poll_data_sources_from_irq();
1353 }
1354 
1355 static void usb_transport_response_ds(btstack_data_source_t *ds, btstack_data_source_callback_type_t callback_type) {
1356     UNUSED(ds);
1357     UNUSED(callback_type);
1358 //    printf("%s packet sent: %d sco can send now: %d\n", __FUNCTION__, acknowledge_count, sco_can_send_now_count);
1359     for(; acknowledge_count>0; --acknowledge_count) {
1360         static const uint8_t event[] = { HCI_EVENT_TRANSPORT_PACKET_SENT, 0 };
1361         packet_handler(HCI_EVENT_PACKET, (uint8_t*)&event[0], sizeof(event));
1362     }
1363 
1364     for(; sco_can_send_now_count>0; --sco_can_send_now_count) {
1365         static const uint8_t event[] = { HCI_EVENT_SCO_CAN_SEND_NOW, 0 };
1366         packet_handler(HCI_EVENT_PACKET, (uint8_t*)&event[0], sizeof(event));
1367     }
1368 
1369 }
1370 
1371 static int usb_send_cmd_packet(uint8_t *packet, int size){
1372     int r;
1373 
1374     if (libusb_state != LIB_USB_TRANSFERS_ALLOCATED) return -1;
1375 //    printf("%s( %p, %d )\n", __FUNCTION__, packet, size );
1376 
1377     struct libusb_transfer *transfer = usb_transfer_list_acquire( default_transfer_list );
1378     uint8_t *data = transfer->buffer;
1379     void *user_data = transfer->user_data;
1380 
1381     // async
1382     libusb_fill_control_setup(data, LIBUSB_REQUEST_TYPE_CLASS | LIBUSB_RECIPIENT_INTERFACE, 0, 0, 0, size);
1383     memcpy(data + LIBUSB_CONTROL_SETUP_SIZE, packet, size);
1384 
1385     // prepare transfer
1386     libusb_fill_control_transfer(transfer, handle, data, async_callback, user_data, 0);
1387 
1388     // submit transfer
1389     assert( transfer->user_data != NULL );
1390     r = libusb_submit_transfer(transfer);
1391 
1392     if (r < 0) {
1393         log_error("Error submitting cmd transfer %d", r);
1394         return -1;
1395     }
1396 
1397     signal_acknowledge();
1398 
1399     return 0;
1400 }
1401 
1402 static int usb_send_acl_packet(uint8_t *packet, int size){
1403     int r;
1404 
1405     if (libusb_state != LIB_USB_TRANSFERS_ALLOCATED) return -1;
1406 //   printf("%s( %p, %d )\n", __FUNCTION__, packet, size );
1407     // log_info("usb_send_acl_packet enter, size %u", size);
1408 
1409     struct libusb_transfer *transfer = usb_transfer_list_acquire( default_transfer_list );
1410     uint8_t *data = transfer->buffer;
1411 
1412     // prepare transfer
1413     memcpy( data, packet, size );
1414     libusb_fill_bulk_transfer(transfer, handle, acl_out_addr, data, size,
1415         async_callback, transfer->user_data, 0);
1416 
1417     assert( transfer->user_data != NULL );
1418     r = libusb_submit_transfer(transfer);
1419 
1420     if (r < 0) {
1421         log_error("Error submitting acl transfer, %d", r);
1422         return -1;
1423     }
1424 
1425     signal_acknowledge();
1426 
1427     return 0;
1428 }
1429 
1430 static int usb_can_send_packet_now(uint8_t packet_type){
1431     switch (packet_type){
1432         case HCI_COMMAND_DATA_PACKET: {
1433             int ret = !usb_transfer_list_empty( default_transfer_list );
1434             if( !ret ) {
1435                 log_error("command transfers shouldn't be empty!");
1436             }
1437             return ret;
1438         }
1439         case HCI_ACL_DATA_PACKET: {
1440             int ret = !usb_transfer_list_empty( default_transfer_list );
1441             if( !ret ) {
1442                 log_error("acl transfers shouldn't be empty!");
1443             }
1444             return ret;
1445         }
1446 
1447 #ifdef ENABLE_SCO_OVER_HCI
1448         case HCI_SCO_DATA_PACKET: {
1449             if (!sco_enabled || !sco_activated) return 0;
1450             int ret = !usb_transfer_list_empty( sco_transfer_list );
1451             if( !ret ) {
1452                 log_error("sco transfers shouldn't be empty!");
1453             }
1454             return ret;
1455         }
1456 #endif
1457         default:
1458             return 0;
1459     }
1460 }
1461 
1462 static int usb_send_packet(uint8_t packet_type, uint8_t * packet, int size){
1463     switch (packet_type){
1464         case HCI_COMMAND_DATA_PACKET:
1465             return usb_send_cmd_packet(packet, size);
1466         case HCI_ACL_DATA_PACKET:
1467             return usb_send_acl_packet(packet, size);
1468 #ifdef ENABLE_SCO_OVER_HCI
1469         case HCI_SCO_DATA_PACKET:
1470             if (!sco_enabled) return -1;
1471             return usb_send_sco_packet(packet, size);
1472 #endif
1473         default:
1474             return -1;
1475     }
1476 }
1477 
1478 #ifdef ENABLE_SCO_OVER_HCI
1479 static void usb_set_sco_config(uint16_t voice_setting, int num_connections){
1480     if (!sco_enabled) return;
1481 
1482     log_info("usb_set_sco_config: voice settings 0x%04x, num connections %u", voice_setting, num_connections);
1483 
1484     if (num_connections != sco_num_connections){
1485         sco_voice_setting = voice_setting;
1486         if (sco_num_connections){
1487             usb_sco_stop();
1488         }
1489         sco_num_connections = num_connections;
1490         if (num_connections){
1491             usb_sco_start();
1492         }
1493     }
1494 }
1495 #endif
1496 
1497 static void usb_register_packet_handler(void (*handler)(uint8_t packet_type, uint8_t *packet, uint16_t size)){
1498     log_info("registering packet handler");
1499     packet_handler = handler;
1500 }
1501 
1502 static void dummy_handler(uint8_t packet_type, uint8_t *packet, uint16_t size){
1503     UNUSED(packet_type);
1504     UNUSED(packet);
1505     UNUSED(size);
1506 }
1507 
1508 // get usb singleton
1509 const hci_transport_t * hci_transport_usb_instance(void) {
1510     if (!hci_transport_usb) {
1511         hci_transport_usb = (hci_transport_t*) malloc( sizeof(hci_transport_t));
1512         memset(hci_transport_usb, 0, sizeof(hci_transport_t));
1513         hci_transport_usb->name                          = "H2_LIBUSB";
1514         hci_transport_usb->open                          = usb_open;
1515         hci_transport_usb->close                         = usb_close;
1516         hci_transport_usb->register_packet_handler       = usb_register_packet_handler;
1517         hci_transport_usb->can_send_packet_now           = usb_can_send_packet_now;
1518         hci_transport_usb->send_packet                   = usb_send_packet;
1519 #ifdef ENABLE_SCO_OVER_HCI
1520         hci_transport_usb->set_sco_config                = usb_set_sco_config;
1521 #endif
1522     }
1523     return hci_transport_usb;
1524 }
1525