developer.intra2net.com Git - libftdi/blob - src/ftdi_stream.c

   1 /***************************************************************************
   2                           ftdi_stream.c  -  description
   3                              -------------------
   4     copyright            : (C) 2009 Micah Dowty 2010 Uwe Bonnes
   5     email                : opensource@intra2net.com
   6  ***************************************************************************/
   7
   8 /***************************************************************************
   9  *                                                                         *
  10  *   This program is free software; you can redistribute it and/or modify  *
  11  *   it under the terms of the GNU Lesser General Public License           *
  12  *   version 2.1 as published by the Free Software Foundation;             *
  13  *                                                                         *
  14  ***************************************************************************/
  15
  16 /* Adapted from
  17  * fastftdi.c - A minimal FTDI FT232H interface for which supports bit-bang
  18  *              mode, but focuses on very high-performance support for
  19  *              synchronous FIFO mode. Requires libusb-1.0
  20  *
  21  * Copyright (C) 2009 Micah Dowty
  22  *
  23  * Permission is hereby granted, free of charge, to any person obtaining a copy
  24  * of this software and associated documentation files (the "Software"), to deal
  25  * in the Software without restriction, including without limitation the rights
  26  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  27  * copies of the Software, and to permit persons to whom the Software is
  28  * furnished to do so, subject to the following conditions:
  29  *
  30  * The above copyright notice and this permission notice shall be included in
  31  * all copies or substantial portions of the Software.
  32  *
  33  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  34  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  35  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  36  * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  37  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  38  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  39  * THE SOFTWARE.
  40  */
  41
  42 #include <stdlib.h>
  43 #include <stdio.h>
  44
  45 #include "ftdi.h"
  46
  47 typedef struct
  48 {
  49     FTDIStreamCallback *callback;
  50     void *userdata;
  51     int packetsize;
  52     int activity;
  53     int result;
  54     FTDIProgressInfo progress;
  55 } FTDIStreamState;
  56
  57 /* Handle callbacks
  58  *
  59  * With Exit request, free memory and release the transfer
  60  *
  61  * state->result is only set when some error happens
  62  */
  63 static void
  64 ftdi_readstream_cb(struct libusb_transfer *transfer)
  65 {
  66    FTDIStreamState *state = transfer->user_data;
  67    int packet_size = state->packetsize;
  68
  69    state->activity++;
  70    if (transfer->status == LIBUSB_TRANSFER_COMPLETED)
  71    {
  72        int i;
  73        uint8_t *ptr = transfer->buffer;
  74        int length = transfer->actual_length;
  75        int numPackets = (length + packet_size - 1) / packet_size;
  76        int res;
  77
  78        for (i = 0; i < numPackets; i++)
  79        {
  80            int payloadLen;
  81            int packetLen = length;
  82
  83            if (packetLen > packet_size)
  84                packetLen = packet_size;
  85
  86            payloadLen = packetLen - 2;
  87            state->progress.current.totalBytes += payloadLen;
  88
  89            res = state->callback(ptr + 2, payloadLen,
  90                                  NULL, state->userdata);
  91
  92            ptr += packetLen;
  93            length -= packetLen;
  94        }
  95        if (res)
  96        {
  97            free(transfer->buffer);
  98            libusb_free_transfer(transfer);
  99        }
 100        else
 101        {
 102            transfer->status = -1;
 103            state->result = libusb_submit_transfer(transfer);
 104        }
 105    }
 106    else
 107    {
 108        fprintf(stderr, "unknown status %d\n",transfer->status);
 109        state->result = LIBUSB_ERROR_IO;
 110    }
 111 }
 112
 113 /**
 114    Helper function to calculate (unix) time differences
 115
 116    \param a timeval
 117    \param b timeval
 118 */
 119 static double
 120 TimevalDiff(const struct timeval *a, const struct timeval *b)
 121 {
 122    return (a->tv_sec - b->tv_sec) + 1e-6 * (a->tv_usec - b->tv_usec);
 123 }
 124
 125 /**
 126     Streaming reading of data from the device
 127
 128     Use asynchronous transfers in libusb-1.0 for high-performance
 129     streaming of data from a device interface back to the PC. This
 130     function continuously transfers data until either an error occurs
 131     or the callback returns a nonzero value. This function returns
 132     a libusb error code or the callback's return value.
 133
 134     For every contiguous block of received data, the callback will
 135     be invoked.
 136
 137     \param  ftdi pointer to ftdi_context
 138     \param  callback to user supplied function for one block of data
 139     \param  userdata
 140     \param  packetsPerTransfer number of packets per transfer
 141     \param  numTransfers Number of transfers per callback
 142
 143 */
 144
 145 int
 146 ftdi_readstream(struct ftdi_context *ftdi,
 147                       FTDIStreamCallback *callback, void *userdata,
 148                       int packetsPerTransfer, int numTransfers)
 149 {
 150     struct libusb_transfer **transfers;
 151     FTDIStreamState state = { callback, userdata, ftdi->max_packet_size, 1 };
 152     int bufferSize = packetsPerTransfer * ftdi->max_packet_size;
 153     int xferIndex;
 154     int err = 0;
 155
 156     /*
 157      * Set up all transfers
 158      */
 159
 160     transfers = calloc(numTransfers, sizeof *transfers);
 161     if (!transfers) {
 162         err = LIBUSB_ERROR_NO_MEM;
 163         goto cleanup;
 164     }
 165
 166     for (xferIndex = 0; xferIndex < numTransfers; xferIndex++)
 167     {
 168         struct libusb_transfer *transfer;
 169
 170         transfer = libusb_alloc_transfer(0);
 171         transfers[xferIndex] = transfer;
 172         if (!transfer) {
 173             err = LIBUSB_ERROR_NO_MEM;
 174             goto cleanup;
 175         }
 176
 177         libusb_fill_bulk_transfer(transfer, ftdi->usb_dev, ftdi->out_ep,
 178                                   malloc(bufferSize), bufferSize,
 179                                   ftdi_readstream_cb,
 180                                   &state, 0);
 181
 182         if (!transfer->buffer) {
 183             err = LIBUSB_ERROR_NO_MEM;
 184             goto cleanup;
 185         }
 186
 187         transfer->status = -1;
 188         err = libusb_submit_transfer(transfer);
 189         if (err)
 190             goto cleanup;
 191     }
 192
 193     /* Start the transfers only when everything has been set up.
 194      * Otherwise the transfers start stuttering and the PC not
 195      * fetching data for several to several ten milliseconds
 196      * and we skip blocks
 197      */
 198     if (ftdi_set_bitmode(ftdi,  0xff, BITMODE_SYNCFF) < 0)
 199     {
 200         fprintf(stderr,"Can't set synchronous fifo mode: %s\n",
 201                 ftdi_get_error_string(ftdi));
 202         goto cleanup;
 203     }
 204
 205     /*
 206      * Run the transfers, and periodically assess progress.
 207      */
 208
 209     gettimeofday(&state.progress.first.time, NULL);
 210
 211     do
 212     {
 213         FTDIProgressInfo  *progress = &state.progress;
 214         const double progressInterval = 1.0;
 215         struct timeval timeout = { 0, ftdi->usb_read_timeout };
 216         struct timeval now;
 217
 218         int err = libusb_handle_events_timeout(ftdi->usb_ctx, &timeout);
 219         if (err ==  LIBUSB_ERROR_INTERRUPTED)
 220             /* restart interrupted events */
 221             err = libusb_handle_events_timeout(ftdi->usb_ctx, &timeout);
 222         if (!state.result)
 223         {
 224             state.result = err;
 225         }
 226         if (state.activity == 0)
 227             state.result = 1;
 228         else
 229             state.activity = 0;
 230
 231         // If enough time has elapsed, update the progress
 232         gettimeofday(&now, NULL);
 233         if (TimevalDiff(&now, &progress->current.time) >= progressInterval)
 234         {
 235             progress->current.time = now;
 236             progress->totalTime = TimevalDiff(&progress->current.time,
 237                                               &progress->first.time);
 238
 239             if (progress->prev.totalBytes)
 240             {
 241                 // We have enough information to calculate rates
 242
 243                 double currentTime;
 244
 245                 currentTime = TimevalDiff(&progress->current.time,
 246                                           &progress->prev.time);
 247
 248                 progress->totalRate =
 249                     progress->current.totalBytes /progress->totalTime;
 250                 progress->currentRate =
 251                     (progress->current.totalBytes -
 252                      progress->prev.totalBytes) / currentTime;
 253             }
 254
 255             state.callback(NULL, 0, progress, state.userdata);
 256             progress->prev = progress->current;
 257
 258         }
 259     } while (!state.result);
 260
 261     /*
 262      * Cancel any outstanding transfers, and free memory.
 263      */
 264
 265  cleanup:
 266     fprintf(stderr, "cleanup\n");
 267     if (transfers)
 268        free(transfers);
 269     if (err)
 270         return err;
 271     else
 272         return state.result;
 273 }
 274