ubcsp.c

这是Linux环境下的蓝牙源代码

	}

	/* We didn't have a packet, or it was reliable
	   Must wait for ACK before allowing another packet to be sent */

	return 0;
}

/*****************************************************************************/
/**                                                                         **/
/** ubcsp_poll                                                              **/
/**                                                                         **/
/** This is the main function for ubcsp                                     **/
/** It performs a number of tasks                                           **/
/**                                                                         **/
/** 1) Send another octet to the UART - escaping as required                **/
/** 2) Setup the payload to be sent after the header has been sent          **/
/** 3) Send the CRC for the packet if required                              **/
/**                                                                         **/
/** 4) Calculate the next Link Establishment State                          **/
/** 5) Send a Link Establishment packet                                     **/
/** 6) Send a normal packet if available                                    **/
/** 7) Send an ACK packet if required                                       **/
/**                                                                         **/
/** 8) Receive octets from UART and deslip them as required                 **/
/** 9) Place received octets into receive header or receive payload buffer  **/
/** 10) Process received packet when SLIP_END is received                   **/
/**                                                                         **/
/** 11) Keep track of ability of caller to delay recalling                  **/
/**                                                                         **/
/*****************************************************************************/

uint8 ubcsp_poll (uint8 *activity)
{
	uint8
		delay = UBCSP_POLL_TIME_IMMEDIATE;

	uint8
		value;

	/* Assume no activity to start with */

	*activity = 0;

	/* If we don't have to delay, then send something if we can */

	if (!ubcsp_config.delay)
	{
		/* Do we have something we are sending to send */

		if (ubcsp_config.send_size)
		{
			/* We have something to send so send it */

			if (ubcsp_config.send_slip_escape)
			{
				/* Last time we send a SLIP_ESCAPE octet
				   this time send the second escape code */

				put_uart (ubcsp_config.send_slip_escape);

				ubcsp_config.send_slip_escape = 0;
			}
			else
			{
#if UBCSP_CRC
				/* get the value to send, and calculate CRC as we go */

				value = *ubcsp_config.send_ptr ++;

				ubcsp_config.send_crc = ubcsp_calc_crc (value, ubcsp_config.send_crc);

				/* Output the octet */

				ubcsp_put_slip_uart (value);
#else
				/* Just output the octet*/

				ubcsp_put_slip_uart (*ubcsp_config.send_ptr ++);
#endif
			}

			/* If we did output a SLIP_ESCAPE, then don't process the end of a block */

			if ((!ubcsp_config.send_slip_escape) && ((ubcsp_config.send_size = ubcsp_config.send_size - 1) == 0))
			{
				/*** We are at the end of a block - either header or payload ***/

				/* setup the next block */

				ubcsp_config.send_ptr = ubcsp_config.next_send_ptr;
				ubcsp_config.send_size = ubcsp_config.next_send_size;
				ubcsp_config.next_send_ptr = 0;
				ubcsp_config.next_send_size = 0;

#if UBCSP_CRC
				/* If we have no successor block
				   then we might need to send the CRC */

				if (!ubcsp_config.send_ptr)
				{
					if (ubcsp_config.need_send_crc)
					{
						/* reverse the CRC from what we computed along the way */

						ubcsp_config.need_send_crc = 0;

						ubcsp_config.send_crc = ubcsp_crc_reverse (ubcsp_config.send_crc);

						/* Save in the send_crc buffer */

						ubcsp_send_crc[0] = (uint8) (ubcsp_config.send_crc >> 8);
						ubcsp_send_crc[1] = (uint8) ubcsp_config.send_crc;

						/* Setup to send this buffer */

						ubcsp_config.send_ptr = ubcsp_send_crc;
						ubcsp_config.send_size = 2;
					}
					else
					{
						/* We don't need to send the crc
						   either we just have, or this packet doesn't include it */

						/* Output the end of FRAME marker */

						put_uart (SLIP_FRAME);

						/* Check if this is an unreliable packet */

						*activity |= ubcsp_sent_packet ();

						/* We've sent the packet, so don't need to have be called quickly soon */

						delay = UBCSP_POLL_TIME_DELAY;
					}
				}
#else
				/* If we have no successor block
				   then we might need to send the CRC */

				if (!ubcsp_config.send_ptr)
				{
					/* Output the end of FRAME marker */

					put_uart (SLIP_FRAME);

					/* Check if this is an unreliable packet */

					*activity |= ubcsp_sent_packet ();

					/* We've sent the packet, so don't need to have be called quickly soon */

					delay = UBCSP_POLL_TIME_DELAY;
				}
#endif
			}
		}
		else if (ubcsp_config.link_establishment_packet == ubcsp_le_none)
		{
			/* We didn't have something to send
			   AND we have no Link Establishment packet to send */

			if (ubcsp_config.link_establishment_resp & 2)
			{
				/* Send the start of FRAME packet */

				put_uart (SLIP_FRAME);

				/* We did require a RESP packet - so setup the send */

				ubcsp_setup_packet ((uint8*) ubcsp_send_le_header, 0, (uint8*) ubcsp_le_buffer[ubcsp_le_conf_resp], 4);

				/* We have now "sent" this packet */

				ubcsp_config.link_establishment_resp = 0;
			}
			else if (ubcsp_config.send_packet)
			{
				/* There is a packet ready to be sent */

				/* Send the start of FRAME packet */

				put_uart (SLIP_FRAME);

				/* Encode up the packet header using ACK and SEQ numbers */

				ubcsp_send_header[0] =
					(ubcsp_config.send_packet->reliable << 7) |
#if UBCSP_CRC
					0x40 |	/* Always use CRC's */
#endif
					(ubcsp_config.ack_number << 3) | 
					(ubcsp_config.sequence_number);

				/* Encode up the packet header's channel and length */
				ubcsp_send_header[1] =
					(ubcsp_config.send_packet->channel & 0x0f) |
					((ubcsp_config.send_packet->length << 4) & 0xf0);

				ubcsp_send_header[2] =
					(ubcsp_config.send_packet->length >> 4) & 0xff;

				/* Let the ubcsp_setup_packet function calculate the header checksum */

				ubcsp_setup_packet ((uint8*) ubcsp_send_header, 1, ubcsp_config.send_packet->payload, ubcsp_config.send_packet->length);

				/* Don't need to send an ACK - we just place on in this packet */

				ubcsp_config.send_ack = 0;
				
#if SHOW_PACKET_ERRORS
				printf (" : %10d Send %d Ack %d\n",
					GetTickCount () % 100000,
					ubcsp_config.sequence_number,
					ubcsp_config.ack_number);
#endif
			}
			else if (ubcsp_config.send_ack)
			{
				/* Send the start of FRAME packet */

				put_uart (SLIP_FRAME);

#if SHOW_PACKET_ERRORS
				printf (" : %10d Send ACK %d\n",
					GetTickCount () % 100000,
					ubcsp_config.ack_number);
#endif

				/* The ack packet is already computed apart from the first octet */

				ubcsp_send_ack_header[0] =
#if UBCSP_CRC
					0x40 | 
#endif
					(ubcsp_config.ack_number << 3);

				/* Let the ubcsp_setup_packet function calculate the header checksum */

				ubcsp_setup_packet (ubcsp_send_ack_header, 1, 0, 0);

				/* We've now sent the ack */

				ubcsp_config.send_ack = 0;
			}
			else
			{
				/* We didn't have a Link Establishment response packet,
				   a normal packet or an ACK packet to send */

				delay = UBCSP_POLL_TIME_DELAY;
			}
		}
		else
		{
#if SHOW_PACKET_ERRORS
//			printf (" : %10d Send LE %d\n",
//				GetTickCount () % 100000,
//				ubcsp_config.link_establishment_packet);
#endif

			/* Send A Link Establishment Message */

			put_uart (SLIP_FRAME);

			/* Send the Link Establishment header followed by the 
			   Link Establishment packet */

			ubcsp_setup_packet ((uint8*) ubcsp_send_le_header, 0, (uint8*) ubcsp_le_buffer[ubcsp_config.link_establishment_packet], 4);

			/* start sending immediately */

			ubcsp_config.delay = 0;

			/* workout what the next link establishment packet should be */

			ubcsp_config.link_establishment_packet = next_le_packet[ubcsp_config.link_establishment_state + ubcsp_config.link_establishment_resp * 4];

			/* We have now delt with any response packet that we needed */

			ubcsp_config.link_establishment_resp = 0;

			return 0;
		}
	}

	/* We now need to receive any octets from the UART */

	while ((ubcsp_config.receive_packet) && (get_uart (&value)))
	{
		/* If the last octet was SLIP_ESCAPE, then special processing is required */

		if (ubcsp_config.receive_slip_escape)
		{
			/* WARNING - out of range values are not detected !!!
			   This will probably be caught with the checksum or CRC check */

			value = ubcsp_deslip[value - SLIP_ESCAPE_FRAME];

			ubcsp_config.receive_slip_escape = 0;
		}
		else
		{
			/* Check for the SLIP_FRAME octet - must be start or end of packet */
			if (value == SLIP_FRAME)
			{
				/* If we had a full header then we have a packet */

				if (ubcsp_config.receive_index >= 0)
				{
					/* process the received packet */

					*activity |= ubcsp_recevied_packet ();

					if (*activity & UBCSP_PACKET_ACK)
					{
						/* We need to ACK this packet, then don't delay its sending */
						ubcsp_config.delay = 0;
					}
				}

				/* Setup to receive the next packet */

				ubcsp_config.receive_index = -4;

				/* Ok, next octet */

				goto finished_receive;
			}
			else if (value == SLIP_ESCAPE)
			{
				/* If we receive a SLIP_ESCAPE,
				   then remember to process the next special octet */

				ubcsp_config.receive_slip_escape = 1;

				goto finished_receive;
			}
		}

		if (ubcsp_config.receive_index < 0)
		{
			/* We are still receiving the header */

			ubcsp_receive_header[ubcsp_config.receive_index + 4] = value;

			ubcsp_config.receive_index ++;
		}
		else if (ubcsp_config.receive_index < ubcsp_config.receive_packet->length)
		{
			/* We are receiving the payload */
			/* We might stop comming here if we are receiving a
			   packet which is longer than the receive_packet->length
			   given by the host */

			ubcsp_config.receive_packet->payload[ubcsp_config.receive_index] = value;

			ubcsp_config.receive_index ++;
		}

finished_receive:
		{
		}
	}

	if (ubcsp_config.delay > 0)
	{
		/* We were delayed so delay some more
		   this could be cancelled if we received something */

		ubcsp_config.delay --;
	}
	else
	{
		/* We had no delay, so use the delay we just decided to us */

		ubcsp_config.delay = delay;
	}

	/* Report the current delay to the user */

	return ubcsp_config.delay;
}

/*****************************************************************************/
/**                                                                         **/
/** ubcsp_end_of_functions                                                  **/
/**                                                                         **/
/*****************************************************************************/

/* This function is only included to allow for the size 
   of the code to be determined */

void ubcsp_end_of_functions (void)
{
}