Pileus Git - ~andy/csm213a-hw/blob - hw2/main.cpp

   1 #include "messages.h"
   2
   3 #include "mbed.h"
   4 #include "serial_irq.h"
   5 #include "serial_dma.h"
   6 #include "timer_dma.h"
   7
   8 /**
   9  * Mode of operation:
  10  *   Devices 1 and 2 synchronize clocks using serial messages.
  11  *
  12  *   1. Each serial message timestamped using the hardware timer capture
  13  *      registers in both the sender and receiver.
  14  *   2. The sender transmits the send timestamp during the next time-sync
  15  *      message.
  16  *   3. The receiver then compares the senders timestamp with it's own
  17  *      timestamp for the corresponding messages and calculates an offset.
  18  *   4. The offset is used to compensate the receivers local clock.
  19  *
  20  *   Time synchronization is performed in both directions.
  21  */
  22
  23 /*******************
  24  * Timer functions *
  25  *******************/
  26
  27 #define NSEC_PER_SEC 1000000000ULL
  28
  29 uint64_t time_last_local; // timestamp at last time sync
  30 uint64_t time_last_world; // offset at last time sync
  31
  32 /**
  33  * Generate time stamp for an async event:
  34  *   local: drift compensated wall-clock time
  35  *   world: nanoseconds in world time world
  36  *   valid: local timestamp at valid valid
  37  */
  38 //uint64_t time_to_local(uint64_t world, uint64_t valid)
  39 //{
  40 //      uint64_t now =
  41 //      local =  + (stamp);
  42 //}
  43
  44 /**
  45  * Generate time stamp for an async event:
  46  *   time:  drift compensated wall-clock time
  47  *   stamp: event timestamp from PIT Module
  48  */
  49 uint64_t time_to_world(uint64_t local)
  50 {
  51         uint64_t elapsed = local - time_last_local;
  52         return time_last_world + elapsed;
  53 }
  54
  55 /**
  56  * Compensate the Real-Time-Clock oscillator for
  57  * temperature and drift errors. Called at 1Hz and
  58  * synchronous to the RTC 1Hz output.
  59  */
  60 void time_rtc_comp(void)
  61 {
  62         // todo
  63 }
  64
  65 /**
  66  * Synchronize the timer internal state with updates
  67  * from an external time sync message.
  68  *   local: our internal timestamp for the event
  69  *   world: reference timestamp from the other device
  70  */
  71 void time_ext_init(uint64_t local, uint64_t world)
  72 {
  73         sirq_printf("initialize clocks: %d -> %d\r\n",
  74                         (int)(local/NSEC_PER_SEC),
  75                         (int)(world/NSEC_PER_SEC));
  76
  77         time_last_local = local;
  78         time_last_world = world;
  79 }
  80
  81 /**
  82  * Synchronize the timer internal state with updates
  83  * from an external time sync message.
  84  *   local: our internal timestamp for the event
  85  *   world: reference timestamp from the other device
  86  */
  87 void time_ext_sync(uint64_t local, uint64_t world)
  88 {
  89         uint64_t guess = time_to_world(local);
  90         uint64_t error = world > guess ? world - guess :
  91                          guess > world ? guess - world : 0;
  92         int      ahead = guess > world;
  93
  94         time_last_local = local;
  95         time_last_world = guess/2 + world/2;
  96
  97         world = time_last_world;
  98
  99         sirq_printf("syncing clocks: %d=%d.%04u -> %d.%04u (err: %s%ld.%09lu)\r\n",
 100                         (int)((local / NSEC_PER_SEC)),
 101                         (int)((guess / NSEC_PER_SEC)),
 102                         (int)((guess % NSEC_PER_SEC)/(NSEC_PER_SEC/10000)),
 103                         (int)((world / NSEC_PER_SEC)),
 104                         (int)((world % NSEC_PER_SEC)/(NSEC_PER_SEC/10000)),
 105                         ahead ? "-" : "",
 106                         (int32_t )(error / (int64_t)NSEC_PER_SEC),
 107                         (uint32_t)(error % (int64_t)NSEC_PER_SEC));
 108 }
 109
 110 /************************
 111  * Serial I/O functions *
 112  ************************/
 113
 114 typedef struct {
 115         int      index;
 116         int      state;
 117         uint8_t  buffer[256];
 118 } parser_t;
 119
 120 const  uint64_t serial_sync_delay = NSEC_PER_SEC / 10; // 1hz
 121 static uint64_t serial_sync_due   = 0;
 122
 123 static tdma_t  *serial_tdma_rcv   = NULL;
 124 static tdma_t  *serial_tdma_xmt   = NULL;
 125
 126 static uint64_t serial_prev_local = 0;
 127 static uint64_t serial_prev_seq   = 0;
 128
 129 static uint64_t serial_xmt_local  = 0;
 130 static uint64_t serial_xmt_seq    = 0;
 131
 132 /**
 133  * Output time sync message
 134  */
 135 void serial_send_sync(sirq_t *port, uint64_t now)
 136 {
 137         if (serial_sync_due == 0 || now < serial_sync_due)
 138                 return; // not ready
 139
 140         // Calculate world time
 141         uint64_t world = time_to_world(serial_xmt_local);
 142
 143         // Message data
 144         header_t   head;
 145         sync_msg_t body;
 146
 147         // Transmit sync message
 148         head.header = MSG_HEADER;
 149         head.msgid  = MSG_ID_SYNC;
 150         head.length = sizeof(body);
 151         head.cksum  = 0; // todo
 152
 153         body.seq          = serial_xmt_seq;
 154         body.time.seconds = world / NSEC_PER_SEC;
 155         body.time.nanosec = world % NSEC_PER_SEC;
 156
 157         sirq_write(port, &head, sizeof(head));
 158         sirq_write(port, &body, sizeof(body));
 159
 160         serial_xmt_seq  += 1;
 161         serial_sync_due  = 0;
 162
 163         // Debug
 164         //sirq_printf("sync msg transmit\r\n");
 165
 166         // save transmit time
 167         for (int i = 0; i < 1000; i++)
 168                 asm("nop");
 169         int valid = tdma_stamp(serial_tdma_xmt, &serial_xmt_local);
 170         if (!valid)
 171                 sirq_printf("missing sync transmit time\r\n");
 172         tdma_reset(serial_tdma_rcv);
 173         tdma_reset(serial_tdma_xmt);
 174 }
 175
 176 /**
 177  * Output external event received message
 178  *   event: id of the received event
 179  *   time:  compensated timestamp of the event
 180  */
 181 void serial_send_event(uint16_t event, uint64_t local)
 182 {
 183         uint64_t world = time_to_world(local);
 184
 185         ntime_t time = {};
 186         time.seconds = (uint32_t)(world / NSEC_PER_SEC);
 187         time.nanosec = (uint32_t)(world % NSEC_PER_SEC);
 188
 189         sirq_printf("event received - %08x:%08x - %u.%09u\r\n",
 190                 (uint32_t)(local >> 32), (uint32_t)local,
 191                 time.seconds, time.nanosec);
 192         // todo
 193 }
 194
 195 /**
 196  * Handle sync message
 197  */
 198 void serial_handle_sync(sync_msg_t *msg)
 199 {
 200         // Read receive timestamp for next time sync message
 201         uint64_t current = 0;
 202         int valid = tdma_stamp(serial_tdma_rcv, &current);
 203         if (!valid)
 204                 sirq_printf("missing sync receive time\r\n");
 205         tdma_reset(serial_tdma_rcv);
 206         tdma_reset(serial_tdma_xmt);
 207
 208         // Lookup times
 209         uint64_t world = ((uint64_t)msg->time.seconds) * NSEC_PER_SEC
 210                        + ((uint64_t)msg->time.nanosec);
 211
 212         // Initialize
 213         if (msg->seq == 0) {
 214                 uint64_t local = tdma_time();
 215                 time_ext_init(local, world);
 216         }
 217
 218         // Valid times timestamp
 219         if (serial_prev_seq == (msg->seq-1)) {
 220                 uint64_t local = serial_prev_local;
 221                 time_ext_sync(local, world);
 222         }
 223
 224         // Queue transmit to other board
 225         serial_sync_due   = tdma_time() + serial_sync_delay;
 226
 227         // Update states
 228         serial_prev_local = current;
 229         serial_prev_seq   = msg->seq;
 230 }
 231
 232 /**
 233  * Handle event message
 234  */
 235 void serial_handle_event(event_msg_t *msg)
 236 {
 237 }
 238
 239 /**
 240  * Deliver message
 241  */
 242 void serial_deliver(int msgid, void *body)
 243 {
 244         switch (msgid) {
 245                 case MSG_ID_SYNC:
 246                         //sirq_printf("received sync msg\r\n");
 247                         serial_handle_sync((sync_msg_t*)body);
 248                         break;
 249                 case MSG_ID_EVENT:
 250                         //sirq_printf("received event msg\r\n");
 251                         serial_handle_event((event_msg_t*)body);
 252                         break;
 253         }
 254 }
 255
 256 /**
 257  * Process serial receive messages
 258  */
 259 void serial_receive(parser_t *parser, int byte)
 260 {
 261         //sirq_printf("serial_receive - %02x\r\n", byte);
 262
 263         // Lookup pointers
 264         header_t *head = (header_t*)parser->buffer;
 265         void     *body = (void*)(head+1);
 266         const int max_length = sizeof(parser->buffer)-sizeof(header_t);
 267
 268         // Process uart messages
 269         parser->buffer[parser->index++] = byte;
 270         switch (parser->state) {
 271                 case 0: // Search
 272                         if (parser->index == sizeof(uint16_t)) {
 273                                 if (head->header == MSG_HEADER) {
 274                                         parser->state = 1;
 275                                 } else {
 276                                         parser->buffer[0] = parser->buffer[1];
 277                                         parser->index = 1;
 278                                 }
 279                         }
 280                         break;
 281                 case 1: // Header
 282                         if (parser->index == sizeof(header_t)) {
 283                                 if (head->length <= max_length &&
 284                                     head->msgid  <= MSG_MAXID) {
 285                                         parser->state = 2;
 286                                 } else {
 287                                         parser->index = 0;
 288                                         parser->state = 0;
 289                                 }
 290                         }
 291                         break;
 292                 case 2: // Data
 293                         if (parser->index == (int)sizeof(header_t)+head->length) {
 294                                 serial_deliver(head->msgid, body);
 295                                 parser->index = 0;
 296                                 parser->state = 0;
 297                         }
 298                         break;
 299         }
 300 }
 301
 302 /********************
 303  * Data definitions *
 304  ********************/
 305
 306 // LEDs
 307 DigitalOut led1(LED1);
 308 DigitalOut led2(LED2);
 309
 310 // Message Parsers
 311 parser_t   parser_dbg;
 312 parser_t   parser_bbb;
 313 parser_t   parser_mbed;
 314
 315 // Serial IRQ
 316 sirq_t    *sirq_dbg;
 317 sirq_t    *sirq_bbb;
 318 sirq_t    *sirq_mbed;
 319
 320 // Timer DMA
 321 tdma_t    *tdma_evt;
 322 tdma_t    *tdma_rcv;
 323 tdma_t    *tdma_xmt;
 324
 325 /*********
 326  * Tasks *
 327  *********/
 328
 329 void task_serial(uint64_t local, uint64_t world)
 330 {
 331         while (sirq_ready(sirq_dbg)) {
 332                 //sirq_printf("serial recv - dbg\r\n");
 333                 serial_receive(&parser_dbg,  sirq_getc(sirq_dbg));
 334         }
 335
 336         while (sirq_ready(sirq_bbb)) {
 337                 //sirq_printf("serial recv - bbb\r\n");
 338                 serial_receive(&parser_bbb,  sirq_getc(sirq_bbb));
 339         }
 340
 341         while (sirq_ready(sirq_mbed)) {
 342                 //sirq_printf("serial recv - mbed\r\n");
 343                 serial_receive(&parser_mbed, sirq_getc(sirq_mbed));
 344         }
 345 }
 346
 347 void task_events(uint64_t local, uint64_t world)
 348 {
 349         uint64_t event = 0;
 350
 351 #ifdef VERBOSE
 352         if (tdma_stamp(tdma_evt, &event)) {
 353                 sirq_printf("event received - evt\r\n");
 354         if (tdma_stamp(tdma_rcv, &event))
 355                 sirq_printf("event received - rcv\r\n");
 356         if (tdma_stamp(tdma_xmt, &event))
 357                 sirq_printf("event received - xmt\r\n");
 358 #endif
 359
 360         if (tdma_stamp(tdma_evt, &event))
 361                 serial_send_event(0, event);
 362         tdma_reset(tdma_evt);
 363 }
 364
 365 void task_sync(uint64_t local, uint64_t world)
 366 {
 367         serial_send_sync(sirq_mbed, local);
 368 }
 369
 370 void task_leds(uint64_t local, uint64_t world)
 371 {
 372         static uint32_t which = 0;
 373         led1 = (which == 0);
 374         led2 = (which == 1);
 375         which ^= 1;
 376 }
 377
 378 void task_debug(uint64_t local, uint64_t world)
 379 {
 380         //tdma_debug(tdma_rcv);
 381 #ifdef VERBOSE
 382         sirq_printf("background - %6u.%02u -> %u.%02u\r\n",
 383                         (uint32_t)(local / NSEC_PER_SEC),
 384                         (uint32_t)(local % NSEC_PER_SEC / 10000000),
 385                         (uint32_t)(world / NSEC_PER_SEC),
 386                         (uint32_t)(world % NSEC_PER_SEC / 10000000));
 387 #endif
 388 }
 389
 390 /********
 391  * Main *
 392  ********/
 393
 394 #define N_ELEM(x) (sizeof(x) / sizeof((x)[0]))
 395
 396 extern void test_main(void);
 397 extern serial_t stdio_uart;
 398
 399 static struct {
 400         void (*task)(uint64_t, uint64_t);
 401         uint64_t period;
 402         uint64_t due;
 403 } tasks[] = {
 404         { task_serial, 0          }, // always
 405         { task_events, 1000000000 }, // always
 406         { task_sync,   0          }, // always
 407         { task_leds,   100000000  }, // 10hz
 408         { task_debug,  1000000000 }, // 1hz
 409 };
 410
 411 void background(void)
 412 {
 413         // Debugging
 414         uint64_t local = tdma_time();
 415         uint64_t world = time_to_world(local);
 416
 417         // Run the scheduler
 418         for (unsigned i = 0; i < N_ELEM(tasks); i++) {
 419                 if (local >= tasks[i].due) {
 420                         tasks[i].task(local, world);
 421                         tasks[i].due += tasks[i].period;
 422                 }
 423         }
 424 }
 425
 426 int main(int argc, char **argv)
 427 {
 428         tdma_init();
 429
 430         // Open serial ports
 431         sirq_dbg   = sirq_open(SIRQ_UART0, USBTX, USBRX, 115200); // to pc
 432         sirq_bbb   = sirq_open(SIRQ_UART1, PTE0,  PTE1,  115200); // to bbb
 433         sirq_mbed  = sirq_open(SIRQ_UART2, PTD3,  PTD2,  115200); // to mbed
 434
 435
 436         // Setup timers
 437         tdma_evt   = tdma_open(TDMA_CHAN0, 3, PTC9,  PullDown); // async event
 438
 439         // mbed time sync
 440         tdma_rcv   = tdma_open(TDMA_CHAN2, 3, PTD2,  PullUp);   // time sync rcv
 441         tdma_xmt   = tdma_open(TDMA_CHAN3, 3, PTD3,  PullUp);   // time sync xmt
 442
 443         // host time sync
 444         //tdma_rcv   = tdma_open(TDMA_CHAN2, 2, USBRX, PullUp); // time sync rcv
 445         //tdma_xmt   = tdma_open(TDMA_CHAN3, 2, USBTX, PullUp); // time sync xmt
 446
 447         // Serial timestamping
 448         serial_tdma_rcv = tdma_rcv;
 449         serial_tdma_xmt = tdma_xmt;
 450
 451         // Run background loop
 452         printf("hello");
 453         while (true)
 454                 background();
 455
 456         // Run tests
 457         //test_main();
 458
 459         return 0;
 460 }