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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; version 2 of the License.
   7  *
   8  * This program is distributed in the hope that it will be useful, but
   9  * WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  11  * General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU General Public License along
  14  * with this program; if not, write to the Free Software Foundation, Inc.,
  15  * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
  16  */
  17
  18 #include "ao.h"
  19
  20 __xdata struct ao_packet_recv ao_rx_packet;
  21 __xdata struct ao_packet ao_tx_packet;
  22 __pdata uint8_t ao_packet_rx_len, ao_packet_rx_used, ao_packet_tx_used;
  23
  24 static __xdata char tx_data[AO_PACKET_MAX];
  25 static __xdata char rx_data[AO_PACKET_MAX];
  26 static __pdata uint8_t rx_seq;
  27
  28 __xdata struct ao_task  ao_packet_task;
  29 __xdata uint8_t ao_packet_enable;
  30 __xdata uint8_t ao_packet_master_sleeping;
  31
  32 void
  33 ao_packet_send(void)
  34 {
  35 #ifdef AO_LED_RED
  36         ao_led_on(AO_LED_RED);
  37 #endif
  38         /* If any tx data is pending then copy it into the tx packet */
  39         if (ao_packet_tx_used && ao_tx_packet.len == 0) {
  40                 ao_xmemcpy(&ao_tx_packet.d, tx_data, ao_packet_tx_used);
  41                 ao_tx_packet.len = ao_packet_tx_used;
  42                 ao_tx_packet.seq++;
  43                 ao_packet_tx_used = 0;
  44                 ao_wakeup(&tx_data);
  45         }
  46         ao_radio_send(&ao_tx_packet, sizeof (ao_tx_packet));
  47 #ifdef AO_LED_RED
  48         ao_led_off(AO_LED_RED);
  49 #endif
  50 }
  51
  52 uint8_t
  53 ao_packet_recv(void)
  54 {
  55         uint8_t dma_done;
  56
  57 #ifdef AO_LED_GREEN
  58         ao_led_on(AO_LED_GREEN);
  59 #endif
  60         dma_done = ao_radio_recv(&ao_rx_packet, sizeof (struct ao_packet_recv));
  61 #ifdef AO_LED_GREEN
  62         ao_led_off(AO_LED_GREEN);
  63 #endif
  64
  65         /* Check to see if we got a valid packet */
  66         if (!dma_done)
  67                 return 0;
  68         if (!(ao_rx_packet.status & AO_RADIO_STATUS_CRC_OK))
  69                 return 0;
  70
  71         /* Accept packets with matching call signs, or any packet if
  72          * our callsign hasn't been configured
  73          */
  74         if (ao_xmemcmp(ao_rx_packet.packet.callsign,
  75                        ao_config.callsign,
  76                        AO_MAX_CALLSIGN) != 0 &&
  77             ao_xmemcmp(ao_config.callsign, CODE_TO_XDATA("N0CALL"), 7) != 0)
  78                 return 0;
  79
  80         /* SYN packets carry no data */
  81         if (ao_rx_packet.packet.len == AO_PACKET_SYN) {
  82                 rx_seq = ao_rx_packet.packet.seq;
  83                 ao_tx_packet.seq = ao_rx_packet.packet.ack;
  84                 ao_tx_packet.ack = rx_seq;
  85         } else if (ao_rx_packet.packet.len) {
  86
  87                 /* Check for incoming data at the next sequence and
  88                  * for an empty data buffer
  89                  */
  90                 if (ao_rx_packet.packet.seq == (uint8_t) (rx_seq + (uint8_t) 1) &&
  91                     ao_packet_rx_used == ao_packet_rx_len) {
  92
  93                         /* Copy data to the receive data buffer and set up the
  94                          * offsets
  95                          */
  96                         ao_xmemcpy(rx_data, ao_rx_packet.packet.d, ao_rx_packet.packet.len);
  97                         ao_packet_rx_used = 0;
  98                         ao_packet_rx_len = ao_rx_packet.packet.len;
  99
 100                         /* Mark the sequence that we've received to
 101                          * let the sender know when we return a packet
 102                          */
 103                         rx_seq = ao_rx_packet.packet.seq;
 104                         ao_tx_packet.ack = rx_seq;
 105
 106                         /* Poke anyone looking for received data */
 107                         ao_wakeup(&ao_stdin_ready);
 108                 }
 109         }
 110
 111         /* If the other side has seen the latest data we queued,
 112          * wake up any task waiting to send data and let them go again
 113          */
 114         if (ao_rx_packet.packet.ack == ao_tx_packet.seq) {
 115                 ao_tx_packet.len = 0;
 116                 ao_wakeup(&ao_tx_packet);
 117         }
 118         return 1;
 119 }
 120
 121 #ifndef PACKET_HAS_MASTER
 122 #define PACKET_HAS_MASTER 1
 123 #endif
 124
 125 #if PACKET_HAS_MASTER
 126 void
 127 ao_packet_flush(void)
 128 {
 129         /* If there is data to send, and this is the master,
 130          * then poke the master to send all queued data
 131          */
 132         if (ao_packet_tx_used && ao_packet_master_sleeping)
 133                 ao_wakeup(&ao_packet_master_sleeping);
 134 }
 135 #endif /* PACKET_HAS_MASTER */
 136
 137 void
 138 ao_packet_putchar(char c) __reentrant
 139 {
 140         while (ao_packet_tx_used == AO_PACKET_MAX && ao_packet_enable) {
 141 #if PACKET_HAS_MASTER
 142                 ao_packet_flush();
 143 #endif
 144                 ao_sleep(&tx_data);
 145         }
 146
 147         if (ao_packet_enable)
 148                 tx_data[ao_packet_tx_used++] = c;
 149 }
 150
 151 char
 152 ao_packet_pollchar(void) __critical
 153 {
 154         if (!ao_packet_enable)
 155                 return AO_READ_AGAIN;
 156
 157         if (ao_packet_rx_used == ao_packet_rx_len)
 158                 return AO_READ_AGAIN;
 159
 160         return rx_data[ao_packet_rx_used++];
 161 }