riointr.c

来自「LINUX 2.6.17.4的源码」· C语言 代码 · 共 658 行 · 第 1/2 页

			 ** Lock the port before we begin working on it.
			 */
			rio_spin_lock(&PortP->portSem);

			/*
			 ** If we can't add anything to the transmit queue, then
			 ** we need do none of this processing.
			 */
			if (!can_add_transmit(&PacketP, PortP)) {
				rio_dprintk(RIO_DEBUG_INTR, "Can't add to port, so skipping.\n");
				rio_spin_unlock(&PortP->portSem);
				continue;
			}

			/*
			 ** find corresponding tty structure. The process of mapping
			 ** the ports puts these here.
			 */
			ttyP = PortP->gs.tty;
			/* If ttyP is NULL, the port is getting closed. Forget about it. */
			if (!ttyP) {
				rio_dprintk(RIO_DEBUG_INTR, "no tty, so skipping.\n");
				rio_spin_unlock(&PortP->portSem);
				continue;
			}
			/*
			 ** If there is more room available we start up the transmit
			 ** data process again. This can be direct I/O, if the cookmode
			 ** is set to COOK_RAW or COOK_MEDIUM, or will be a call to the
			 ** riotproc( T_OUTPUT ) if we are in COOK_WELL mode, to fetch
			 ** characters via the line discipline. We must always call
			 ** the line discipline,
			 ** so that user input characters can be echoed correctly.
			 **
			 ** ++++ Update +++++
			 ** With the advent of double buffering, we now see if
			 ** TxBufferOut-In is non-zero. If so, then we copy a packet
			 ** to the output place, and set it going. If this empties
			 ** the buffer, then we must issue a wakeup( ) on OUT.
			 ** If it frees space in the buffer then we must issue
			 ** a wakeup( ) on IN.
			 **
			 ** ++++ Extra! Extra! If PortP->WflushFlag is set, then we
			 ** have to send a WFLUSH command down the PHB, to mark the
			 ** end point of a WFLUSH. We also need to clear out any
			 ** data from the double buffer! ( note that WflushFlag is a
			 ** *count* of the number of WFLUSH commands outstanding! )
			 **
			 ** ++++ And there's more!
			 ** If an RTA is powered off, then on again, and rebooted,
			 ** whilst it has ports open, then we need to re-open the ports.
			 ** ( reasonable enough ). We can't do this when we spot the
			 ** re-boot, in interrupt time, because the queue is probably
			 ** full. So, when we come in here, we need to test if any
			 ** ports are in this condition, and re-open the port before
			 ** we try to send any more data to it. Now, the re-booted
			 ** RTA will be discarding packets from the PHB until it
			 ** receives this open packet, but don't worry tooo much
			 ** about that. The one thing that is interesting is the
			 ** combination of this effect and the WFLUSH effect!
			 */
			/* For now don't handle RTA reboots. -- REW.
			   Reenabled. Otherwise RTA reboots didn't work. Duh. -- REW */
			if (PortP->MagicFlags) {
				if (PortP->MagicFlags & MAGIC_REBOOT) {
					/*
					 ** well, the RTA has been rebooted, and there is room
					 ** on its queue to add the open packet that is required.
					 **
					 ** The messy part of this line is trying to decide if
					 ** we need to call the Param function as a tty or as
					 ** a modem.
					 ** DONT USE CLOCAL AS A TEST FOR THIS!
					 **
					 ** If we can't param the port, then move on to the
					 ** next port.
					 */
					PortP->InUse = NOT_INUSE;

					rio_spin_unlock(&PortP->portSem);
					if (RIOParam(PortP, OPEN, ((PortP->Cor2Copy & (COR2_RTSFLOW | COR2_CTSFLOW)) == (COR2_RTSFLOW | COR2_CTSFLOW)) ? 1 : 0, DONT_SLEEP) == RIO_FAIL) {
						continue;	/* with next port */
					}
					rio_spin_lock(&PortP->portSem);
					PortP->MagicFlags &= ~MAGIC_REBOOT;
				}

				/*
				 ** As mentioned above, this is a tacky hack to cope
				 ** with WFLUSH
				 */
				if (PortP->WflushFlag) {
					rio_dprintk(RIO_DEBUG_INTR, "Want to WFLUSH mark this port\n");

					if (PortP->InUse)
						rio_dprintk(RIO_DEBUG_INTR, "FAILS - PORT IS IN USE\n");
				}

				while (PortP->WflushFlag && can_add_transmit(&PacketP, PortP) && (PortP->InUse == NOT_INUSE)) {
					int p;
					struct PktCmd *PktCmdP;

					rio_dprintk(RIO_DEBUG_INTR, "Add WFLUSH marker to data queue\n");
					/*
					 ** make it look just like a WFLUSH command
					 */
					PktCmdP = (struct PktCmd *) &PacketP->data[0];

					writeb(WFLUSH, &PktCmdP->Command);

					p = PortP->HostPort % (u16) PORTS_PER_RTA;

					/*
					 ** If second block of ports for 16 port RTA, add 8
					 ** to index 8-15.
					 */
					if (PortP->SecondBlock)
						p += PORTS_PER_RTA;

					writeb(p, &PktCmdP->PhbNum);

					/*
					 ** to make debuggery easier
					 */
					writeb('W', &PacketP->data[2]);
					writeb('F', &PacketP->data[3]);
					writeb('L', &PacketP->data[4]);
					writeb('U', &PacketP->data[5]);
					writeb('S', &PacketP->data[6]);
					writeb('H', &PacketP->data[7]);
					writeb(' ', &PacketP->data[8]);
					writeb('0' + PortP->WflushFlag, &PacketP->data[9]);
					writeb(' ', &PacketP->data[10]);
					writeb(' ', &PacketP->data[11]);
					writeb('\0', &PacketP->data[12]);

					/*
					 ** its two bytes long!
					 */
					writeb(PKT_CMD_BIT | 2, &PacketP->len);

					/*
					 ** queue it!
					 */
					if (!(PortP->State & RIO_DELETED)) {
						add_transmit(PortP);
						/*
						 ** Count chars tx'd for port statistics reporting
						 */
						if (PortP->statsGather)
							PortP->txchars += 2;
					}

					if (--(PortP->WflushFlag) == 0) {
						PortP->MagicFlags &= ~MAGIC_FLUSH;
					}

					rio_dprintk(RIO_DEBUG_INTR, "Wflush count now stands at %d\n", PortP->WflushFlag);
				}
				if (PortP->MagicFlags & MORE_OUTPUT_EYGOR) {
					if (PortP->MagicFlags & MAGIC_FLUSH) {
						PortP->MagicFlags |= MORE_OUTPUT_EYGOR;
					} else {
						if (!can_add_transmit(&PacketP, PortP)) {
							rio_spin_unlock(&PortP->portSem);
							continue;
						}
						rio_spin_unlock(&PortP->portSem);
						RIOTxEnable((char *) PortP);
						rio_spin_lock(&PortP->portSem);
						PortP->MagicFlags &= ~MORE_OUTPUT_EYGOR;
					}
				}
			}


			/*
			 ** If we can't add anything to the transmit queue, then
			 ** we need do none of the remaining processing.
			 */
			if (!can_add_transmit(&PacketP, PortP)) {
				rio_spin_unlock(&PortP->portSem);
				continue;
			}

			rio_spin_unlock(&PortP->portSem);
			RIOTxEnable((char *) PortP);
		}
	}
}

/*
** Routine for handling received data for tty drivers
*/
static void RIOReceive(struct rio_info *p, struct Port *PortP)
{
	struct tty_struct *TtyP;
	unsigned short transCount;
	struct PKT *PacketP;
	register unsigned int DataCnt;
	unsigned char *ptr;
	unsigned char *buf;
	int copied = 0;

	static int intCount, RxIntCnt;

	/*
	 ** The receive data process is to remove packets from the
	 ** PHB until there aren't any more or the current cblock
	 ** is full. When this occurs, there will be some left over
	 ** data in the packet, that we must do something with.
	 ** As we haven't unhooked the packet from the read list
	 ** yet, we can just leave the packet there, having first
	 ** made a note of how far we got. This means that we need
	 ** a pointer per port saying where we start taking the
	 ** data from - this will normally be zero, but when we
	 ** run out of space it will be set to the offset of the
	 ** next byte to copy from the packet data area. The packet
	 ** length field is decremented by the number of bytes that
	 ** we succesfully removed from the packet. When this reaches
	 ** zero, we reset the offset pointer to be zero, and free
	 ** the packet from the front of the queue.
	 */

	intCount++;

	TtyP = PortP->gs.tty;
	if (!TtyP) {
		rio_dprintk(RIO_DEBUG_INTR, "RIOReceive: tty is null. \n");
		return;
	}

	if (PortP->State & RIO_THROTTLE_RX) {
		rio_dprintk(RIO_DEBUG_INTR, "RIOReceive: Throttled. Can't handle more input.\n");
		return;
	}

	if (PortP->State & RIO_DELETED) {
		while (can_remove_receive(&PacketP, PortP)) {
			remove_receive(PortP);
			put_free_end(PortP->HostP, PacketP);
		}
	} else {
		/*
		 ** loop, just so long as:
		 **   i ) there's some data ( i.e. can_remove_receive )
		 **  ii ) we haven't been blocked
		 ** iii ) there's somewhere to put the data
		 **  iv ) we haven't outstayed our welcome
		 */
		transCount = 1;
		while (can_remove_receive(&PacketP, PortP)
		       && transCount) {
			RxIntCnt++;

			/*
			 ** check that it is not a command!
			 */
			if (PacketP->len & PKT_CMD_BIT) {
				rio_dprintk(RIO_DEBUG_INTR, "RIO: unexpected command packet received on PHB\n");
				/*      rio_dprint(RIO_DEBUG_INTR, (" sysport   = %d\n", p->RIOPortp->PortNum)); */
				rio_dprintk(RIO_DEBUG_INTR, " dest_unit = %d\n", PacketP->dest_unit);
				rio_dprintk(RIO_DEBUG_INTR, " dest_port = %d\n", PacketP->dest_port);
				rio_dprintk(RIO_DEBUG_INTR, " src_unit  = %d\n", PacketP->src_unit);
				rio_dprintk(RIO_DEBUG_INTR, " src_port  = %d\n", PacketP->src_port);
				rio_dprintk(RIO_DEBUG_INTR, " len	   = %d\n", PacketP->len);
				rio_dprintk(RIO_DEBUG_INTR, " control   = %d\n", PacketP->control);
				rio_dprintk(RIO_DEBUG_INTR, " csum	   = %d\n", PacketP->csum);
				rio_dprintk(RIO_DEBUG_INTR, "	 data bytes: ");
				for (DataCnt = 0; DataCnt < PKT_MAX_DATA_LEN; DataCnt++)
					rio_dprintk(RIO_DEBUG_INTR, "%d\n", PacketP->data[DataCnt]);
				remove_receive(PortP);
				put_free_end(PortP->HostP, PacketP);
				continue;	/* with next packet */
			}

			/*
			 ** How many characters can we move 'upstream' ?
			 **
			 ** Determine the minimum of the amount of data
			 ** available and the amount of space in which to
			 ** put it.
			 **
			 ** 1.        Get the packet length by masking 'len'
			 **   for only the length bits.
			 ** 2.        Available space is [buffer size] - [space used]
			 **
			 ** Transfer count is the minimum of packet length
			 ** and available space.
			 */

			transCount = tty_buffer_request_room(TtyP, PacketP->len & PKT_LEN_MASK);
			rio_dprintk(RIO_DEBUG_REC, "port %d: Copy %d bytes\n", PortP->PortNum, transCount);
			/*
			 ** To use the following 'kkprintfs' for debugging - change the '#undef'
			 ** to '#define', (this is the only place ___DEBUG_IT___ occurs in the
			 ** driver).
			 */
			ptr = (unsigned char *) PacketP->data + PortP->RxDataStart;

			tty_prepare_flip_string(TtyP, &buf, transCount);
			rio_memcpy_fromio(buf, ptr, transCount);
			PortP->RxDataStart += transCount;
			PacketP->len -= transCount;
			copied += transCount;



			if (PacketP->len == 0) {
				/*
				 ** If we have emptied the packet, then we can
				 ** free it, and reset the start pointer for
				 ** the next packet.
				 */
				remove_receive(PortP);
				put_free_end(PortP->HostP, PacketP);
				PortP->RxDataStart = 0;
			}
		}
	}
	if (copied) {
		rio_dprintk(RIO_DEBUG_REC, "port %d: pushing tty flip buffer: %d total bytes copied.\n", PortP->PortNum, copied);
		tty_flip_buffer_push(TtyP);
	}

	return;
}