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   1 /*
   2  * Copyright © 2009 Keith Packard <keithp@keithp.com>
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License as published by
   6  * the Free Software Foundation; either version 2 of the License, or
   7  * (at your option) any later version.
   8  *
   9  * This program is distributed in the hope that it will be useful, but
  10  * WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12  * General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License along
  15  * with this program; if not, write to the Free Software Foundation, Inc.,
  16  * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
  17  */
  18
  19 #include "ao.h"
  20
  21 struct ao_packet_recv ao_rx_packet;
  22 struct ao_packet ao_tx_packet;
  23 uint8_t ao_packet_rx_len, ao_packet_rx_used, ao_packet_tx_used;
  24
  25 static uint8_t tx_data[AO_PACKET_MAX];
  26 static uint8_t rx_data[AO_PACKET_MAX];
  27 static uint8_t rx_seq;
  28
  29 struct ao_task  ao_packet_task;
  30 uint8_t ao_packet_enable;
  31 uint8_t ao_packet_restart;
  32
  33 #if PACKET_HAS_MASTER
  34 uint8_t ao_packet_master_sleeping;
  35 #endif
  36
  37 void
  38 ao_packet_send(void)
  39 {
  40 #ifdef AO_LED_RED
  41         ao_led_on(AO_LED_RED);
  42 #endif
  43         /* If any tx data is pending then copy it into the tx packet */
  44         if (ao_packet_tx_used && ao_tx_packet.len == 0) {
  45                 memcpy(&ao_tx_packet.d, tx_data, ao_packet_tx_used);
  46                 ao_tx_packet.len = ao_packet_tx_used;
  47                 ao_tx_packet.seq++;
  48                 ao_packet_tx_used = 0;
  49                 ao_wakeup(&tx_data);
  50         }
  51         ao_radio_send(&ao_tx_packet, sizeof (ao_tx_packet));
  52 #ifdef AO_LED_RED
  53         ao_led_off(AO_LED_RED);
  54 #endif
  55 }
  56
  57 uint8_t
  58 ao_packet_recv(uint16_t timeout)
  59 {
  60         uint8_t dma_done;
  61
  62 #ifdef AO_LED_GREEN
  63         ao_led_on(AO_LED_GREEN);
  64 #endif
  65         dma_done = ao_radio_recv(&ao_rx_packet, sizeof (struct ao_packet_recv), timeout);
  66 #ifdef AO_LED_GREEN
  67         ao_led_off(AO_LED_GREEN);
  68 #endif
  69 #if AO_PROFILE
  70                 {
  71                         extern uint32_t ao_rx_start_tick, ao_rx_packet_tick, ao_rx_done_tick, ao_rx_last_done_tick;
  72                         extern uint32_t ao_fec_decode_start, ao_fec_decode_end;
  73
  74                         printf ("between packet: %d\n", ao_rx_start_tick - ao_rx_last_done_tick);
  75                         printf ("receive start delay: %d\n", ao_rx_packet_tick - ao_rx_start_tick);
  76                         printf ("decode time: %d\n", ao_fec_decode_end - ao_fec_decode_start);
  77                         printf ("rx cleanup: %d\n\n", ao_rx_done_tick - ao_fec_decode_end);
  78                         flush();
  79                 }
  80 #endif
  81
  82         /* Check to see if we got a valid packet */
  83         if (!dma_done)
  84                 return 0;
  85         if (!(ao_rx_packet.status & AO_RADIO_STATUS_CRC_OK))
  86                 return 0;
  87
  88         /* Accept packets with matching call signs, or any packet if
  89          * our callsign hasn't been configured
  90          */
  91         if (memcmp(ao_rx_packet.packet.callsign,
  92                        ao_config.callsign,
  93                        AO_MAX_CALLSIGN) != 0 &&
  94             memcmp(ao_config.callsign, "N0CALL", 7) != 0)
  95                 return 0;
  96
  97         /* SYN packets carry no data */
  98         if (ao_rx_packet.packet.len == AO_PACKET_SYN) {
  99                 rx_seq = ao_rx_packet.packet.seq;
 100                 ao_tx_packet.seq = ao_rx_packet.packet.ack;
 101                 ao_tx_packet.ack = rx_seq;
 102         } else if (ao_rx_packet.packet.len) {
 103
 104                 /* Check for incoming data at the next sequence and
 105                  * for an empty data buffer
 106                  */
 107                 if ((ao_rx_packet.packet.seq == (uint8_t) (rx_seq + (uint8_t) 1) ||
 108                      ao_packet_restart) &&
 109                     ao_packet_rx_used == ao_packet_rx_len) {
 110
 111                         /* Copy data to the receive data buffer and set up the
 112                          * offsets
 113                          */
 114                         memcpy(rx_data, ao_rx_packet.packet.d, ao_rx_packet.packet.len);
 115                         ao_packet_rx_used = 0;
 116                         ao_packet_rx_len = ao_rx_packet.packet.len;
 117
 118                         /* Mark the sequence that we've received to
 119                          * let the sender know when we return a packet
 120                          */
 121                         rx_seq = ao_rx_packet.packet.seq;
 122                         ao_tx_packet.ack = rx_seq;
 123
 124                         /* Poke anyone looking for received data */
 125                         ao_wakeup(&ao_stdin_ready);
 126                 }
 127         }
 128         ao_packet_restart = 0;
 129
 130         /* If the other side has seen the latest data we queued,
 131          * wake up any task waiting to send data and let them go again
 132          */
 133         if (ao_rx_packet.packet.ack == ao_tx_packet.seq) {
 134                 ao_tx_packet.len = 0;
 135                 ao_wakeup(&ao_tx_packet);
 136         }
 137         return 1;
 138 }
 139
 140 #if PACKET_HAS_MASTER
 141 void
 142 ao_packet_flush(void)
 143 {
 144         /* If there is data to send, and this is the master,
 145          * then poke the master to send all queued data
 146          */
 147         if (ao_packet_tx_used && ao_packet_master_sleeping)
 148                 ao_wakeup(&ao_packet_master_sleeping);
 149 }
 150 #endif /* PACKET_HAS_MASTER */
 151
 152 void
 153 ao_packet_putchar(char c)
 154 {
 155         /* No need to block interrupts, all variables here
 156          * are only manipulated in task context
 157          */
 158         while (ao_packet_tx_used == AO_PACKET_MAX && ao_packet_enable) {
 159 #if PACKET_HAS_MASTER
 160                 ao_packet_flush();
 161 #endif
 162                 ao_sleep(&tx_data);
 163         }
 164
 165         if (ao_packet_enable)
 166                 tx_data[ao_packet_tx_used++] = c;
 167 }
 168
 169 /* May be called with interrupts blocked */
 170 int
 171 _ao_packet_pollchar(void)
 172 {
 173         if (!ao_packet_enable)
 174                 return AO_READ_AGAIN;
 175
 176         if (ao_packet_rx_used == ao_packet_rx_len)
 177                 return AO_READ_AGAIN;
 178
 179         return rx_data[ao_packet_rx_used++];
 180 }