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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 & PKT_APPEND_STATUS_1_CRC_OK))
  69                 return 0;
  70
  71         /* SYN packets carry no data */
  72         if (ao_rx_packet.packet.len == AO_PACKET_SYN) {
  73                 rx_seq = ao_rx_packet.packet.seq;
  74                 ao_tx_packet.seq = ao_rx_packet.packet.ack;
  75                 ao_tx_packet.ack = rx_seq;
  76         } else if (ao_rx_packet.packet.len) {
  77
  78                 /* Check for incoming data at the next sequence and
  79                  * for an empty data buffer
  80                  */
  81                 if (ao_rx_packet.packet.seq == (uint8_t) (rx_seq + (uint8_t) 1) &&
  82                     ao_packet_rx_used == ao_packet_rx_len) {
  83
  84                         /* Copy data to the receive data buffer and set up the
  85                          * offsets
  86                          */
  87                         ao_xmemcpy(rx_data, ao_rx_packet.packet.d, ao_rx_packet.packet.len);
  88                         ao_packet_rx_used = 0;
  89                         ao_packet_rx_len = ao_rx_packet.packet.len;
  90
  91                         /* Mark the sequence that we've received to
  92                          * let the sender know when we return a packet
  93                          */
  94                         rx_seq = ao_rx_packet.packet.seq;
  95                         ao_tx_packet.ack = rx_seq;
  96
  97                         /* Poke anyone looking for received data */
  98                         ao_wakeup(&ao_stdin_ready);
  99                 }
 100         }
 101
 102         /* If the other side has seen the latest data we queued,
 103          * wake up any task waiting to send data and let them go again
 104          */
 105         if (ao_rx_packet.packet.ack == ao_tx_packet.seq) {
 106                 ao_tx_packet.len = 0;
 107                 ao_wakeup(&ao_tx_packet);
 108         }
 109         return 1;
 110 }
 111
 112 #ifndef PACKET_HAS_MASTER
 113 #define PACKET_HAS_MASTER 1
 114 #endif
 115
 116 #if PACKET_HAS_MASTER
 117 void
 118 ao_packet_flush(void)
 119 {
 120         /* If there is data to send, and this is the master,
 121          * then poke the master to send all queued data
 122          */
 123         if (ao_packet_tx_used && ao_packet_master_sleeping)
 124                 ao_wakeup(&ao_packet_master_sleeping);
 125 }
 126 #endif /* PACKET_HAS_MASTER */
 127
 128 void
 129 ao_packet_putchar(char c) __reentrant
 130 {
 131         while (ao_packet_tx_used == AO_PACKET_MAX && ao_packet_enable) {
 132 #if PACKET_HAS_MASTER
 133                 ao_packet_flush();
 134 #endif
 135                 ao_sleep(&tx_data);
 136         }
 137
 138         if (ao_packet_enable)
 139                 tx_data[ao_packet_tx_used++] = c;
 140 }
 141
 142 char
 143 ao_packet_pollchar(void) __critical
 144 {
 145         if (!ao_packet_enable)
 146                 return AO_READ_AGAIN;
 147
 148         if (ao_packet_rx_used == ao_packet_rx_len)
 149                 return AO_READ_AGAIN;
 150
 151         return rx_data[ao_packet_rx_used++];
 152 }