transport.c

优龙2410linux2.6.8内核源代码

		/* if we stalled the data transfer it means command failed */
		if (result == USB_STOR_XFER_STALLED)
			return USB_STOR_TRANSPORT_FAILED;
		if (result > USB_STOR_XFER_STALLED)
			return USB_STOR_TRANSPORT_ERROR;
	}

	/* STATUS STAGE */
	result = usb_stor_intr_transfer(us, us->iobuf, 2);
	US_DEBUGP("Got interrupt data (0x%x, 0x%x)\n", 
			us->iobuf[0], us->iobuf[1]);
	if (result != USB_STOR_XFER_GOOD)
		return USB_STOR_TRANSPORT_ERROR;

	/* UFI gives us ASC and ASCQ, like a request sense
	 *
	 * REQUEST_SENSE and INQUIRY don't affect the sense data on UFI
	 * devices, so we ignore the information for those commands.  Note
	 * that this means we could be ignoring a real error on these
	 * commands, but that can't be helped.
	 */
	if (us->subclass == US_SC_UFI) {
		if (srb->cmnd[0] == REQUEST_SENSE ||
		    srb->cmnd[0] == INQUIRY)
			return USB_STOR_TRANSPORT_GOOD;
		if (us->iobuf[0])
			goto Failed;
		return USB_STOR_TRANSPORT_GOOD;
	}

	/* If not UFI, we interpret the data as a result code 
	 * The first byte should always be a 0x0.
	 *
	 * Some bogus devices don't follow that rule.  They stuff the ASC
	 * into the first byte -- so if it's non-zero, call it a failure.
	 */
	if (us->iobuf[0]) {
		US_DEBUGP("CBI IRQ data showed reserved bType 0x%x\n",
				us->iobuf[0]);
		goto Failed;

	}

	/* The second byte & 0x0F should be 0x0 for good, otherwise error */
	switch (us->iobuf[1] & 0x0F) {
		case 0x00: 
			return USB_STOR_TRANSPORT_GOOD;
		case 0x01: 
			goto Failed;
	}
	return USB_STOR_TRANSPORT_ERROR;

	/* the CBI spec requires that the bulk pipe must be cleared
	 * following any data-in/out command failure (section 2.4.3.1.3)
	 */
  Failed:
	if (pipe)
		usb_stor_clear_halt(us, pipe);
	return USB_STOR_TRANSPORT_FAILED;
}

/*
 * Control/Bulk transport
 */
int usb_stor_CB_transport(Scsi_Cmnd *srb, struct us_data *us)
{
	unsigned int transfer_length = srb->request_bufflen;
	int result;

	/* COMMAND STAGE */
	/* let's send the command via the control pipe */
	result = usb_stor_ctrl_transfer(us, us->send_ctrl_pipe,
				      US_CBI_ADSC, 
				      USB_TYPE_CLASS | USB_RECIP_INTERFACE, 0, 
				      us->ifnum, srb->cmnd, srb->cmd_len);

	/* check the return code for the command */
	US_DEBUGP("Call to usb_stor_ctrl_transfer() returned %d\n", result);

	/* if we stalled the command, it means command failed */
	if (result == USB_STOR_XFER_STALLED) {
		return USB_STOR_TRANSPORT_FAILED;
	}

	/* Uh oh... serious problem here */
	if (result != USB_STOR_XFER_GOOD) {
		return USB_STOR_TRANSPORT_ERROR;
	}

	/* DATA STAGE */
	/* transfer the data payload for this command, if one exists*/
	if (transfer_length) {
		unsigned int pipe = srb->sc_data_direction == SCSI_DATA_READ ? 
				us->recv_bulk_pipe : us->send_bulk_pipe;
		result = usb_stor_bulk_transfer_sg(us, pipe,
					srb->request_buffer, transfer_length,
					srb->use_sg, &srb->resid);
		US_DEBUGP("CB data stage result is 0x%x\n", result);

		/* if we stalled the data transfer it means command failed */
		if (result == USB_STOR_XFER_STALLED)
			return USB_STOR_TRANSPORT_FAILED;
		if (result > USB_STOR_XFER_STALLED)
			return USB_STOR_TRANSPORT_ERROR;
	}

	/* STATUS STAGE */
	/* NOTE: CB does not have a status stage.  Silly, I know.  So
	 * we have to catch this at a higher level.
	 */
	return USB_STOR_TRANSPORT_GOOD;
}

/*
 * Bulk only transport
 */

/* Determine what the maximum LUN supported is */
int usb_stor_Bulk_max_lun(struct us_data *us)
{
	int result;

	/* issue the command */
	result = usb_stor_control_msg(us, us->recv_ctrl_pipe,
				 US_BULK_GET_MAX_LUN, 
				 USB_DIR_IN | USB_TYPE_CLASS | 
				 USB_RECIP_INTERFACE,
				 0, us->ifnum, us->iobuf, 1, HZ);

	US_DEBUGP("GetMaxLUN command result is %d, data is %d\n", 
		  result, us->iobuf[0]);

	/* if we have a successful request, return the result */
	if (result == 1)
		return us->iobuf[0];

	/* 
	 * Some devices (i.e. Iomega Zip100) need this -- apparently
	 * the bulk pipes get STALLed when the GetMaxLUN request is
	 * processed.   This is, in theory, harmless to all other devices
	 * (regardless of if they stall or not).
	 */
	if (result == -EPIPE) {
		usb_stor_clear_halt(us, us->recv_bulk_pipe);
		usb_stor_clear_halt(us, us->send_bulk_pipe);
		/* return the default -- no LUNs */
		return 0;
	}

	/* An answer or a STALL are the only valid responses.  If we get
	 * something else, return an indication of error */
	return -1;
}

int usb_stor_Bulk_transport(Scsi_Cmnd *srb, struct us_data *us)
{
	struct bulk_cb_wrap *bcb = (struct bulk_cb_wrap *) us->iobuf;
	struct bulk_cs_wrap *bcs = (struct bulk_cs_wrap *) us->iobuf;
	unsigned int transfer_length = srb->request_bufflen;
	unsigned int residue;
	int result;
	int fake_sense = 0;
	unsigned int cswlen;

	/* set up the command wrapper */
	bcb->Signature = cpu_to_le32(US_BULK_CB_SIGN);
	bcb->DataTransferLength = cpu_to_le32(transfer_length);
	bcb->Flags = srb->sc_data_direction == SCSI_DATA_READ ? 1 << 7 : 0;
	bcb->Tag = srb->serial_number;
	bcb->Lun = srb->device->lun;
	if (us->flags & US_FL_SCM_MULT_TARG)
		bcb->Lun |= srb->device->id << 4;
	bcb->Length = srb->cmd_len;

	/* copy the command payload */
	memset(bcb->CDB, 0, sizeof(bcb->CDB));
	memcpy(bcb->CDB, srb->cmnd, bcb->Length);

	/* send it to out endpoint */
	US_DEBUGP("Bulk Command S 0x%x T 0x%x L %d F %d Trg %d LUN %d CL %d\n",
			le32_to_cpu(bcb->Signature), bcb->Tag,
			le32_to_cpu(bcb->DataTransferLength), bcb->Flags,
			(bcb->Lun >> 4), (bcb->Lun & 0x0F), 
			bcb->Length);
	result = usb_stor_bulk_transfer_buf(us, us->send_bulk_pipe,
				bcb, US_BULK_CB_WRAP_LEN, NULL);
	US_DEBUGP("Bulk command transfer result=%d\n", result);
	if (result != USB_STOR_XFER_GOOD)
		return USB_STOR_TRANSPORT_ERROR;

	/* DATA STAGE */
	/* send/receive data payload, if there is any */
	if (transfer_length) {
		unsigned int pipe = srb->sc_data_direction == SCSI_DATA_READ ? 
				us->recv_bulk_pipe : us->send_bulk_pipe;
		result = usb_stor_bulk_transfer_sg(us, pipe,
					srb->request_buffer, transfer_length,
					srb->use_sg, &srb->resid);
		US_DEBUGP("Bulk data transfer result 0x%x\n", result);
		if (result == USB_STOR_XFER_ERROR)
			return USB_STOR_TRANSPORT_ERROR;

		/* If the device tried to send back more data than the
		 * amount requested, the spec requires us to transfer
		 * the CSW anyway.  Since there's no point retrying the
		 * the command, we'll return fake sense data indicating
		 * Illegal Request, Invalid Field in CDB.
		 */
		if (result == USB_STOR_XFER_LONG)
			fake_sense = 1;
	}

	/* See flow chart on pg 15 of the Bulk Only Transport spec for
	 * an explanation of how this code works.
	 */

	/* get CSW for device status */
	US_DEBUGP("Attempting to get CSW...\n");
	result = usb_stor_bulk_transfer_buf(us, us->recv_bulk_pipe,
				bcs, US_BULK_CS_WRAP_LEN, &cswlen);

	/* Some broken devices add unnecessary zero-length packets to the
	 * end of their data transfers.  Such packets show up as 0-length
	 * CSWs.  If we encounter such a thing, try to read the CSW again.
	 */
	if (result == USB_STOR_XFER_SHORT && cswlen == 0) {
		US_DEBUGP("Received 0-length CSW; retrying...\n");
		result = usb_stor_bulk_transfer_buf(us, us->recv_bulk_pipe,
				bcs, US_BULK_CS_WRAP_LEN, &cswlen);
	}

	/* did the attempt to read the CSW fail? */
	if (result == USB_STOR_XFER_STALLED) {

		/* get the status again */
		US_DEBUGP("Attempting to get CSW (2nd try)...\n");
		result = usb_stor_bulk_transfer_buf(us, us->recv_bulk_pipe,
				bcs, US_BULK_CS_WRAP_LEN, NULL);
	}

	/* if we still have a failure at this point, we're in trouble */
	US_DEBUGP("Bulk status result = %d\n", result);
	if (result != USB_STOR_XFER_GOOD)
		return USB_STOR_TRANSPORT_ERROR;

	/* check bulk status */
	residue = le32_to_cpu(bcs->Residue);
	US_DEBUGP("Bulk Status S 0x%x T 0x%x R %u Stat 0x%x\n",
			le32_to_cpu(bcs->Signature), bcs->Tag, 
			residue, bcs->Status);
	if ((bcs->Signature != cpu_to_le32(US_BULK_CS_SIGN) &&
		    bcs->Signature != cpu_to_le32(US_BULK_CS_OLYMPUS_SIGN)) ||
			bcs->Tag != srb->serial_number || 
			bcs->Status > US_BULK_STAT_PHASE) {
		US_DEBUGP("Bulk logical error\n");
		return USB_STOR_TRANSPORT_ERROR;
	}

	/* try to compute the actual residue, based on how much data
	 * was really transferred and what the device tells us */
	residue = min(residue, transfer_length);
	srb->resid = max(srb->resid, (int) residue);

	/* based on the status code, we report good or bad */
	switch (bcs->Status) {
		case US_BULK_STAT_OK:
			/* device babbled -- return fake sense data */
			if (fake_sense) {
				memcpy(srb->sense_buffer, 
				       usb_stor_sense_invalidCDB, 
				       sizeof(usb_stor_sense_invalidCDB));
				return USB_STOR_TRANSPORT_NO_SENSE;
			}

			/* command good -- note that data could be short */
			return USB_STOR_TRANSPORT_GOOD;

		case US_BULK_STAT_FAIL:
			/* command failed */
			return USB_STOR_TRANSPORT_FAILED;

		case US_BULK_STAT_PHASE:
			/* phase error -- note that a transport reset will be
			 * invoked by the invoke_transport() function
			 */
			return USB_STOR_TRANSPORT_ERROR;
	}

	/* we should never get here, but if we do, we're in trouble */
	return USB_STOR_TRANSPORT_ERROR;
}

/***********************************************************************
 * Reset routines
 ***********************************************************************/

/* This is the common part of the device reset code.
 *
 * It's handy that every transport mechanism uses the control endpoint for
 * resets.
 *
 * Basically, we send a reset with a 20-second timeout, so we don't get
 * jammed attempting to do the reset.
 */
static int usb_stor_reset_common(struct us_data *us,
		u8 request, u8 requesttype,
		u16 value, u16 index, void *data, u16 size)
{
	int result;
	int result2;
	int rc = FAILED;

	/* Let the SCSI layer know we are doing a reset, set the
	 * RESETTING bit, and clear the ABORTING bit so that the reset
	 * may proceed.
	 */
	scsi_lock(us->host);
	usb_stor_report_device_reset(us);
	set_bit(US_FLIDX_RESETTING, &us->flags);
	clear_bit(US_FLIDX_ABORTING, &us->flags);
	scsi_unlock(us->host);

	/* A 20-second timeout may seem rather long, but a LaCie
	 * StudioDrive USB2 device takes 16+ seconds to get going
	 * following a powerup or USB attach event.
	 */
	result = usb_stor_control_msg(us, us->send_ctrl_pipe,
			request, requesttype, value, index, data, size,
			20*HZ);
	if (result < 0) {
		US_DEBUGP("Soft reset failed: %d\n", result);
		goto Done;
	}

 	/* Give the device some time to recover from the reset,
 	 * but don't delay disconnect processing. */
 	wait_event_interruptible_timeout(us->dev_reset_wait,
 			test_bit(US_FLIDX_DISCONNECTING, &us->flags),
 			HZ*6);
	if (test_bit(US_FLIDX_DISCONNECTING, &us->flags)) {
		US_DEBUGP("Reset interrupted by disconnect\n");
		goto Done;
	}

	US_DEBUGP("Soft reset: clearing bulk-in endpoint halt\n");
	result = usb_stor_clear_halt(us, us->recv_bulk_pipe);

	US_DEBUGP("Soft reset: clearing bulk-out endpoint halt\n");
	result2 = usb_stor_clear_halt(us, us->send_bulk_pipe);

	/* return a result code based on the result of the control message */
	if (result < 0 || result2 < 0) {
		US_DEBUGP("Soft reset failed\n");
		goto Done;
	}
	US_DEBUGP("Soft reset done\n");
	rc = SUCCESS;

  Done:
	clear_bit(US_FLIDX_RESETTING, &us->flags);
	return rc;
}

/* This issues a CB[I] Reset to the device in question
 */
#define CB_RESET_CMD_SIZE	12

int usb_stor_CB_reset(struct us_data *us)
{
	US_DEBUGP("%s called\n", __FUNCTION__);

	memset(us->iobuf, 0xFF, CB_RESET_CMD_SIZE);
	us->iobuf[0] = SEND_DIAGNOSTIC;
	us->iobuf[1] = 4;
	return usb_stor_reset_common(us, US_CBI_ADSC, 
				 USB_TYPE_CLASS | USB_RECIP_INTERFACE,
				 0, us->ifnum, us->iobuf, CB_RESET_CMD_SIZE);
}

/* This issues a Bulk-only Reset to the device in question, including
 * clearing the subsequent endpoint halts that may occur.
 */
int usb_stor_Bulk_reset(struct us_data *us)
{
	US_DEBUGP("%s called\n", __FUNCTION__);

	return usb_stor_reset_common(us, US_BULK_RESET_REQUEST, 
				 USB_TYPE_CLASS | USB_RECIP_INTERFACE,
				 0, us->ifnum, NULL, 0);
}