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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         ao_led_on(AO_LED_RED);
  36         /* If any tx data is pending then copy it into the tx packet */
  37         if (ao_packet_tx_used && ao_tx_packet.len == 0) {
  38                 memcpy(&ao_tx_packet.d, tx_data, ao_packet_tx_used);
  39                 ao_tx_packet.len = ao_packet_tx_used;
  40                 ao_tx_packet.seq++;
  41                 ao_packet_tx_used = 0;
  42                 ao_wakeup(&tx_data);
  43         }
  44         ao_radio_send(&ao_tx_packet, sizeof (ao_tx_packet));
  45         ao_led_off(AO_LED_RED);
  46 }
  47
  48 uint8_t
  49 ao_packet_recv(void)
  50 {
  51         uint8_t dma_done;
  52
  53 #ifdef AO_LED_GREEN
  54         ao_led_on(AO_LED_GREEN);
  55 #endif
  56         dma_done = ao_radio_recv(&ao_rx_packet, sizeof (struct ao_packet_recv));
  57 #ifdef AO_LED_GREEN
  58         ao_led_off(AO_LED_GREEN);
  59 #endif
  60
  61         /* Check to see if we got a valid packet */
  62         if (!dma_done)
  63                 return 0;
  64         if (!(ao_rx_packet.status & PKT_APPEND_STATUS_1_CRC_OK))
  65                 return 0;
  66
  67         /* SYN packets carry no data */
  68         if (ao_rx_packet.packet.len == AO_PACKET_SYN) {
  69                 rx_seq = ao_rx_packet.packet.seq;
  70                 ao_tx_packet.seq = ao_rx_packet.packet.ack;
  71                 ao_tx_packet.ack = rx_seq;
  72         } else if (ao_rx_packet.packet.len) {
  73
  74                 /* Check for incoming data at the next sequence and
  75                  * for an empty data buffer
  76                  */
  77                 if (ao_rx_packet.packet.seq == (uint8_t) (rx_seq + (uint8_t) 1) &&
  78                     ao_packet_rx_used == ao_packet_rx_len) {
  79
  80                         /* Copy data to the receive data buffer and set up the
  81                          * offsets
  82                          */
  83                         memcpy(rx_data, ao_rx_packet.packet.d, ao_rx_packet.packet.len);
  84                         ao_packet_rx_used = 0;
  85                         ao_packet_rx_len = ao_rx_packet.packet.len;
  86
  87                         /* Mark the sequence that we've received to
  88                          * let the sender know when we return a packet
  89                          */
  90                         rx_seq = ao_rx_packet.packet.seq;
  91                         ao_tx_packet.ack = rx_seq;
  92
  93                         /* Poke anyone looking for received data */
  94                         ao_wakeup(&ao_stdin_ready);
  95                 }
  96         }
  97
  98         /* If the other side has seen the latest data we queued,
  99          * wake up any task waiting to send data and let them go again
 100          */
 101         if (ao_rx_packet.packet.ack == ao_tx_packet.seq) {
 102                 ao_tx_packet.len = 0;
 103                 ao_wakeup(&ao_tx_packet);
 104         }
 105         return 1;
 106 }
 107
 108 #ifndef PACKET_HAS_MASTER
 109 #define PACKET_HAS_MASTER 1
 110 #endif
 111
 112 #if PACKET_HAS_MASTER
 113 void
 114 ao_packet_flush(void)
 115 {
 116         /* If there is data to send, and this is the master,
 117          * then poke the master to send all queued data
 118          */
 119         if (ao_packet_tx_used && ao_packet_master_sleeping)
 120                 ao_wakeup(&ao_packet_master_sleeping);
 121 }
 122 #endif /* PACKET_HAS_MASTER */
 123
 124 void
 125 ao_packet_putchar(char c) __reentrant
 126 {
 127         while (ao_packet_tx_used == AO_PACKET_MAX && ao_packet_enable) {
 128 #if PACKET_HAS_MASTER
 129                 ao_packet_flush();
 130 #endif
 131                 ao_sleep(&tx_data);
 132         }
 133
 134         if (ao_packet_enable)
 135                 tx_data[ao_packet_tx_used++] = c;
 136 }
 137
 138 char
 139 ao_packet_pollchar(void) __critical
 140 {
 141         if (!ao_packet_enable)
 142                 return AO_READ_AGAIN;
 143
 144         if (ao_packet_rx_used == ao_packet_rx_len)
 145                 return AO_READ_AGAIN;
 146
 147         return rx_data[ao_packet_rx_used++];
 148 }