in2000.c

来自「linux 内核源代码」· C语言 代码 · 共 2,045 行 · 第 1/5 页

	/*
	 * Add the cmd to the end of 'input_Q'. Note that REQUEST_SENSE
	 * commands are added to the head of the queue so that the desired
	 * sense data is not lost before REQUEST_SENSE executes.
	 */

	if (!(hostdata->input_Q) || (cmd->cmnd[0] == REQUEST_SENSE)) {
		cmd->host_scribble = (uchar *) hostdata->input_Q;
		hostdata->input_Q = cmd;
	} else {		/* find the end of the queue */
		for (tmp = (Scsi_Cmnd *) hostdata->input_Q; tmp->host_scribble; tmp = (Scsi_Cmnd *) tmp->host_scribble);
		tmp->host_scribble = (uchar *) cmd;
	}

/* We know that there's at least one command in 'input_Q' now.
 * Go see if any of them are runnable!
 */

	in2000_execute(cmd->device->host);

	DB(DB_QUEUE_COMMAND, printk(")Q-%ld ", cmd->serial_number))
	    return 0;
}



/*
 * This routine attempts to start a scsi command. If the host_card is
 * already connected, we give up immediately. Otherwise, look through
 * the input_Q, using the first command we find that's intended
 * for a currently non-busy target/lun.
 * Note that this function is always called with interrupts already
 * disabled (either from in2000_queuecommand() or in2000_intr()).
 */
static void in2000_execute(struct Scsi_Host *instance)
{
	struct IN2000_hostdata *hostdata;
	Scsi_Cmnd *cmd, *prev;
	int i;
	unsigned short *sp;
	unsigned short f;
	unsigned short flushbuf[16];


	hostdata = (struct IN2000_hostdata *) instance->hostdata;

	DB(DB_EXECUTE, printk("EX("))

	    if (hostdata->selecting || hostdata->connected) {

		DB(DB_EXECUTE, printk(")EX-0 "))

		    return;
	}

	/*
	 * Search through the input_Q for a command destined
	 * for an idle target/lun.
	 */

	cmd = (Scsi_Cmnd *) hostdata->input_Q;
	prev = NULL;
	while (cmd) {
		if (!(hostdata->busy[cmd->device->id] & (1 << cmd->device->lun)))
			break;
		prev = cmd;
		cmd = (Scsi_Cmnd *) cmd->host_scribble;
	}

	/* quit if queue empty or all possible targets are busy */

	if (!cmd) {

		DB(DB_EXECUTE, printk(")EX-1 "))

		    return;
	}

	/*  remove command from queue */

	if (prev)
		prev->host_scribble = cmd->host_scribble;
	else
		hostdata->input_Q = (Scsi_Cmnd *) cmd->host_scribble;

#ifdef PROC_STATISTICS
	hostdata->cmd_cnt[cmd->device->id]++;
#endif

/*
 * Start the selection process
 */

	if (is_dir_out(cmd))
		write_3393(hostdata, WD_DESTINATION_ID, cmd->device->id);
	else
		write_3393(hostdata, WD_DESTINATION_ID, cmd->device->id | DSTID_DPD);

/* Now we need to figure out whether or not this command is a good
 * candidate for disconnect/reselect. We guess to the best of our
 * ability, based on a set of hierarchical rules. When several
 * devices are operating simultaneously, disconnects are usually
 * an advantage. In a single device system, or if only 1 device
 * is being accessed, transfers usually go faster if disconnects
 * are not allowed:
 *
 * + Commands should NEVER disconnect if hostdata->disconnect =
 *   DIS_NEVER (this holds for tape drives also), and ALWAYS
 *   disconnect if hostdata->disconnect = DIS_ALWAYS.
 * + Tape drive commands should always be allowed to disconnect.
 * + Disconnect should be allowed if disconnected_Q isn't empty.
 * + Commands should NOT disconnect if input_Q is empty.
 * + Disconnect should be allowed if there are commands in input_Q
 *   for a different target/lun. In this case, the other commands
 *   should be made disconnect-able, if not already.
 *
 * I know, I know - this code would flunk me out of any
 * "C Programming 101" class ever offered. But it's easy
 * to change around and experiment with for now.
 */

	cmd->SCp.phase = 0;	/* assume no disconnect */
	if (hostdata->disconnect == DIS_NEVER)
		goto no;
	if (hostdata->disconnect == DIS_ALWAYS)
		goto yes;
	if (cmd->device->type == 1)	/* tape drive? */
		goto yes;
	if (hostdata->disconnected_Q)	/* other commands disconnected? */
		goto yes;
	if (!(hostdata->input_Q))	/* input_Q empty? */
		goto no;
	for (prev = (Scsi_Cmnd *) hostdata->input_Q; prev; prev = (Scsi_Cmnd *) prev->host_scribble) {
		if ((prev->device->id != cmd->device->id) || (prev->device->lun != cmd->device->lun)) {
			for (prev = (Scsi_Cmnd *) hostdata->input_Q; prev; prev = (Scsi_Cmnd *) prev->host_scribble)
				prev->SCp.phase = 1;
			goto yes;
		}
	}
	goto no;

      yes:
	cmd->SCp.phase = 1;

#ifdef PROC_STATISTICS
	hostdata->disc_allowed_cnt[cmd->device->id]++;
#endif

      no:
	write_3393(hostdata, WD_SOURCE_ID, ((cmd->SCp.phase) ? SRCID_ER : 0));

	write_3393(hostdata, WD_TARGET_LUN, cmd->device->lun);
	write_3393(hostdata, WD_SYNCHRONOUS_TRANSFER, hostdata->sync_xfer[cmd->device->id]);
	hostdata->busy[cmd->device->id] |= (1 << cmd->device->lun);

	if ((hostdata->level2 <= L2_NONE) || (hostdata->sync_stat[cmd->device->id] == SS_UNSET)) {

		/*
		 * Do a 'Select-With-ATN' command. This will end with
		 * one of the following interrupts:
		 *    CSR_RESEL_AM:  failure - can try again later.
		 *    CSR_TIMEOUT:   failure - give up.
		 *    CSR_SELECT:    success - proceed.
		 */

		hostdata->selecting = cmd;

/* Every target has its own synchronous transfer setting, kept in
 * the sync_xfer array, and a corresponding status byte in sync_stat[].
 * Each target's sync_stat[] entry is initialized to SS_UNSET, and its
 * sync_xfer[] entry is initialized to the default/safe value. SS_UNSET
 * means that the parameters are undetermined as yet, and that we
 * need to send an SDTR message to this device after selection is
 * complete. We set SS_FIRST to tell the interrupt routine to do so,
 * unless we don't want to even _try_ synchronous transfers: In this
 * case we set SS_SET to make the defaults final.
 */
		if (hostdata->sync_stat[cmd->device->id] == SS_UNSET) {
			if (hostdata->sync_off & (1 << cmd->device->id))
				hostdata->sync_stat[cmd->device->id] = SS_SET;
			else
				hostdata->sync_stat[cmd->device->id] = SS_FIRST;
		}
		hostdata->state = S_SELECTING;
		write_3393_count(hostdata, 0);	/* this guarantees a DATA_PHASE interrupt */
		write_3393_cmd(hostdata, WD_CMD_SEL_ATN);
	}

	else {

		/*
		 * Do a 'Select-With-ATN-Xfer' command. This will end with
		 * one of the following interrupts:
		 *    CSR_RESEL_AM:  failure - can try again later.
		 *    CSR_TIMEOUT:   failure - give up.
		 *    anything else: success - proceed.
		 */

		hostdata->connected = cmd;
		write_3393(hostdata, WD_COMMAND_PHASE, 0);

		/* copy command_descriptor_block into WD chip
		 * (take advantage of auto-incrementing)
		 */

		write1_io(WD_CDB_1, IO_WD_ADDR);
		for (i = 0; i < cmd->cmd_len; i++)
			write1_io(cmd->cmnd[i], IO_WD_DATA);

		/* The wd33c93 only knows about Group 0, 1, and 5 commands when
		 * it's doing a 'select-and-transfer'. To be safe, we write the
		 * size of the CDB into the OWN_ID register for every case. This
		 * way there won't be problems with vendor-unique, audio, etc.
		 */

		write_3393(hostdata, WD_OWN_ID, cmd->cmd_len);

		/* When doing a non-disconnect command, we can save ourselves a DATA
		 * phase interrupt later by setting everything up now. With writes we
		 * need to pre-fill the fifo; if there's room for the 32 flush bytes,
		 * put them in there too - that'll avoid a fifo interrupt. Reads are
		 * somewhat simpler.
		 * KLUDGE NOTE: It seems that you can't completely fill the fifo here:
		 * This results in the IO_FIFO_COUNT register rolling over to zero,
		 * and apparently the gate array logic sees this as empty, not full,
		 * so the 3393 chip is never signalled to start reading from the
		 * fifo. Or maybe it's seen as a permanent fifo interrupt condition.
		 * Regardless, we fix this by temporarily pretending that the fifo
		 * is 16 bytes smaller. (I see now that the old driver has a comment
		 * about "don't fill completely" in an analogous place - must be the
		 * same deal.) This results in CDROM, swap partitions, and tape drives
		 * needing an extra interrupt per write command - I think we can live
		 * with that!
		 */

		if (!(cmd->SCp.phase)) {
			write_3393_count(hostdata, cmd->SCp.this_residual);
			write_3393(hostdata, WD_CONTROL, CTRL_IDI | CTRL_EDI | CTRL_BUS);
			write1_io(0, IO_FIFO_WRITE);	/* clear fifo counter, write mode */

			if (is_dir_out(cmd)) {
				hostdata->fifo = FI_FIFO_WRITING;
				if ((i = cmd->SCp.this_residual) > (IN2000_FIFO_SIZE - 16))
					i = IN2000_FIFO_SIZE - 16;
				cmd->SCp.have_data_in = i;	/* this much data in fifo */
				i >>= 1;	/* Gulp. Assuming modulo 2. */
				sp = (unsigned short *) cmd->SCp.ptr;
				f = hostdata->io_base + IO_FIFO;

#ifdef FAST_WRITE_IO

				FAST_WRITE2_IO();
#else
				while (i--)
					write2_io(*sp++, IO_FIFO);

#endif

				/* Is there room for the flush bytes? */

				if (cmd->SCp.have_data_in <= ((IN2000_FIFO_SIZE - 16) - 32)) {
					sp = flushbuf;
					i = 16;

#ifdef FAST_WRITE_IO

					FAST_WRITE2_IO();
#else
					while (i--)
						write2_io(0, IO_FIFO);

#endif

				}
			}

			else {
				write1_io(0, IO_FIFO_READ);	/* put fifo in read mode */
				hostdata->fifo = FI_FIFO_READING;
				cmd->SCp.have_data_in = 0;	/* nothing transferred yet */
			}

		} else {
			write_3393_count(hostdata, 0);	/* this guarantees a DATA_PHASE interrupt */
		}
		hostdata->state = S_RUNNING_LEVEL2;
		write_3393_cmd(hostdata, WD_CMD_SEL_ATN_XFER);
	}

	/*
	 * Since the SCSI bus can handle only 1 connection at a time,
	 * we get out of here now. If the selection fails, or when
	 * the command disconnects, we'll come back to this routine
	 * to search the input_Q again...
	 */

	DB(DB_EXECUTE, printk("%s%ld)EX-2 ", (cmd->SCp.phase) ? "d:" : "", cmd->serial_number))

}



static void transfer_pio(uchar * buf, int cnt, int data_in_dir, struct IN2000_hostdata *hostdata)
{
	uchar asr;

	DB(DB_TRANSFER, printk("(%p,%d,%s)", buf, cnt, data_in_dir ? "in" : "out"))

	    write_3393(hostdata, WD_CONTROL, CTRL_IDI | CTRL_EDI | CTRL_POLLED);
	write_3393_count(hostdata, cnt);
	write_3393_cmd(hostdata, WD_CMD_TRANS_INFO);
	if (data_in_dir) {
		do {
			asr = READ_AUX_STAT();
			if (asr & ASR_DBR)
				*buf++ = read_3393(hostdata, WD_DATA);
		} while (!(asr & ASR_INT));
	} else {
		do {
			asr = READ_AUX_STAT();
			if (asr & ASR_DBR)
				write_3393(hostdata, WD_DATA, *buf++);
		} while (!(asr & ASR_INT));
	}

	/* Note: we are returning with the interrupt UN-cleared.
	 * Since (presumably) an entire I/O operation has
	 * completed, the bus phase is probably different, and
	 * the interrupt routine will discover this when it
	 * responds to the uncleared int.
	 */

}



static void transfer_bytes(Scsi_Cmnd * cmd, int data_in_dir)
{
	struct IN2000_hostdata *hostdata;
	unsigned short *sp;
	unsigned short f;
	int i;

	hostdata = (struct IN2000_hostdata *) cmd->device->host->hostdata;

/* Normally, you'd expect 'this_residual' to be non-zero here.
 * In a series of scatter-gather transfers, however, this
 * routine will usually be called with 'this_residual' equal
 * to 0 and 'buffers_residual' non-zero. This means that a
 * previous transfer completed, clearing 'this_residual', and
 * now we need to setup the next scatter-gather buffer as the
 * source or destination for THIS transfer.
 */
	if (!cmd->SCp.this_residual && cmd->SCp.buffers_residual) {
		++cmd->SCp.buffer;
		--cmd->SCp.buffers_residual;
		cmd->SCp.this_residual = cmd->SCp.buffer->length;
		cmd->SCp.ptr = sg_virt(cmd->SCp.buffer);
	}

/* Set up hardware registers */

	write_3393(hostdata, WD_SYNCHRONOUS_TRANSFER, hostdata->sync_xfer[cmd->device->id]);
	write_3393_count(hostdata, cmd->SCp.this_residual);
	write_3393(hostdata, WD_CONTROL, CTRL_IDI | CTRL_EDI | CTRL_BUS);
	write1_io(0, IO_FIFO_WRITE);	/* zero counter, assume write */

/* Reading is easy. Just issue the command and return - we'll
 * get an interrupt later when we have actual data to worry about.
 */

	if (data_in_dir) {
		write1_io(0, IO_FIFO_READ);
		if ((hostdata->level2 >= L2_DATA) || (hostdata->level2 == L2_BASIC && cmd->SCp.phase == 0)) {
			write_3393(hostdata, WD_COMMAND_PHASE, 0x45);
			write_3393_cmd(hostdata, WD_CMD_SEL_ATN_XFER);
			hostdata->state = S_RUNNING_LEVEL2;
		} else
			write_3393_cmd(hostdata, WD_CMD_TRANS_INFO);
		hostdata->fifo = FI_FIFO_READING;
		cmd->SCp.have_data_in = 0;
		return;
	}

/* Writing is more involved - we'll start the WD chip and write as
 * much data to the fifo as we can right now. Later interrupts will
 * write any bytes that don't make it at this stage.
 */

	if ((hostdata->level2 >= L2_DATA) || (hostdata->level2 == L2_BASIC && cmd->SCp.phase == 0)) {
		write_3393(hostdata, WD_COMMAND_PHASE, 0x45);
		write_3393_cmd(hostdata, WD_CMD_SEL_ATN_XFER);
		hostdata->state = S_RUNNING_LEVEL2;
	} else
		write_3393_cmd(hostdata, WD_CMD_TRANS_INFO);
	hostdata->fifo = FI_FIFO_WRITING;
	sp = (unsigned short *) cmd->SCp.ptr;

	if ((i = cmd->SCp.this_residual) > IN2000_FIFO_SIZE)
		i = IN2000_FIFO_SIZE;
	cmd->SCp.have_data_in = i;
	i >>= 1;		/* Gulp. We assume this_residual is modulo 2 */
	f = hostdata->io_base + IO_FIFO;

#ifdef FAST_WRITE_IO

	FAST_WRITE2_IO();
#else
	while (i--)