ub.c

linux 内核源代码

				break;
			cmd->error = rc;
			cmd->state = UB_CMDST_DONE;
		} else {
			if (!ub_is_completed(&sc->work_done))
				break;
			del_timer(&sc->work_timer);
			ub_scsi_urb_compl(sc, cmd);
		}
	}
}

static void ub_scsi_urb_compl(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
{
	struct urb *urb = &sc->work_urb;
	struct bulk_cs_wrap *bcs;
	int len;
	int rc;

	if (atomic_read(&sc->poison)) {
		ub_state_done(sc, cmd, -ENODEV);
		return;
	}

	if (cmd->state == UB_CMDST_CLEAR) {
		if (urb->status == -EPIPE) {
			/*
			 * STALL while clearning STALL.
			 * The control pipe clears itself - nothing to do.
			 */
			printk(KERN_NOTICE "%s: stall on control pipe\n",
			    sc->name);
			goto Bad_End;
		}

		/*
		 * We ignore the result for the halt clear.
		 */

		/* reset the endpoint toggle */
		usb_settoggle(sc->dev, usb_pipeendpoint(sc->last_pipe),
			usb_pipeout(sc->last_pipe), 0);

		ub_state_sense(sc, cmd);

	} else if (cmd->state == UB_CMDST_CLR2STS) {
		if (urb->status == -EPIPE) {
			printk(KERN_NOTICE "%s: stall on control pipe\n",
			    sc->name);
			goto Bad_End;
		}

		/*
		 * We ignore the result for the halt clear.
		 */

		/* reset the endpoint toggle */
		usb_settoggle(sc->dev, usb_pipeendpoint(sc->last_pipe),
			usb_pipeout(sc->last_pipe), 0);

		ub_state_stat(sc, cmd);

	} else if (cmd->state == UB_CMDST_CLRRS) {
		if (urb->status == -EPIPE) {
			printk(KERN_NOTICE "%s: stall on control pipe\n",
			    sc->name);
			goto Bad_End;
		}

		/*
		 * We ignore the result for the halt clear.
		 */

		/* reset the endpoint toggle */
		usb_settoggle(sc->dev, usb_pipeendpoint(sc->last_pipe),
			usb_pipeout(sc->last_pipe), 0);

		ub_state_stat_counted(sc, cmd);

	} else if (cmd->state == UB_CMDST_CMD) {
		switch (urb->status) {
		case 0:
			break;
		case -EOVERFLOW:
			goto Bad_End;
		case -EPIPE:
			rc = ub_submit_clear_stall(sc, cmd, sc->last_pipe);
			if (rc != 0) {
				printk(KERN_NOTICE "%s: "
				    "unable to submit clear (%d)\n",
				    sc->name, rc);
				/*
				 * This is typically ENOMEM or some other such shit.
				 * Retrying is pointless. Just do Bad End on it...
				 */
				ub_state_done(sc, cmd, rc);
				return;
			}
			cmd->state = UB_CMDST_CLEAR;
			return;
		case -ESHUTDOWN:	/* unplug */
		case -EILSEQ:		/* unplug timeout on uhci */
			ub_state_done(sc, cmd, -ENODEV);
			return;
		default:
			goto Bad_End;
		}
		if (urb->actual_length != US_BULK_CB_WRAP_LEN) {
			goto Bad_End;
		}

		if (cmd->dir == UB_DIR_NONE || cmd->nsg < 1) {
			ub_state_stat(sc, cmd);
			return;
		}

		// udelay(125);		// usb-storage has this
		ub_data_start(sc, cmd);

	} else if (cmd->state == UB_CMDST_DATA) {
		if (urb->status == -EPIPE) {
			rc = ub_submit_clear_stall(sc, cmd, sc->last_pipe);
			if (rc != 0) {
				printk(KERN_NOTICE "%s: "
				    "unable to submit clear (%d)\n",
				    sc->name, rc);
				ub_state_done(sc, cmd, rc);
				return;
			}
			cmd->state = UB_CMDST_CLR2STS;
			return;
		}
		if (urb->status == -EOVERFLOW) {
			/*
			 * A babble? Failure, but we must transfer CSW now.
			 */
			cmd->error = -EOVERFLOW;	/* A cheap trick... */
			ub_state_stat(sc, cmd);
			return;
		}

		if (cmd->dir == UB_DIR_WRITE) {
			/*
			 * Do not continue writes in case of a failure.
			 * Doing so would cause sectors to be mixed up,
			 * which is worse than sectors lost.
			 *
			 * We must try to read the CSW, or many devices
			 * get confused.
			 */
			len = urb->actual_length;
			if (urb->status != 0 ||
			    len != cmd->sgv[cmd->current_sg].length) {
				cmd->act_len += len;

				cmd->error = -EIO;
				ub_state_stat(sc, cmd);
				return;
			}

		} else {
			/*
			 * If an error occurs on read, we record it, and
			 * continue to fetch data in order to avoid bubble.
			 *
			 * As a small shortcut, we stop if we detect that
			 * a CSW mixed into data.
			 */
			if (urb->status != 0)
				cmd->error = -EIO;

			len = urb->actual_length;
			if (urb->status != 0 ||
			    len != cmd->sgv[cmd->current_sg].length) {
				if ((len & 0x1FF) == US_BULK_CS_WRAP_LEN)
					goto Bad_End;
			}
		}

		cmd->act_len += urb->actual_length;

		if (++cmd->current_sg < cmd->nsg) {
			ub_data_start(sc, cmd);
			return;
		}
		ub_state_stat(sc, cmd);

	} else if (cmd->state == UB_CMDST_STAT) {
		if (urb->status == -EPIPE) {
			rc = ub_submit_clear_stall(sc, cmd, sc->last_pipe);
			if (rc != 0) {
				printk(KERN_NOTICE "%s: "
				    "unable to submit clear (%d)\n",
				    sc->name, rc);
				ub_state_done(sc, cmd, rc);
				return;
			}

			/*
			 * Having a stall when getting CSW is an error, so
			 * make sure uppper levels are not oblivious to it.
			 */
			cmd->error = -EIO;		/* A cheap trick... */

			cmd->state = UB_CMDST_CLRRS;
			return;
		}

		/* Catch everything, including -EOVERFLOW and other nasties. */
		if (urb->status != 0)
			goto Bad_End;

		if (urb->actual_length == 0) {
			ub_state_stat_counted(sc, cmd);
			return;
		}

		/*
		 * Check the returned Bulk protocol status.
		 * The status block has to be validated first.
		 */

		bcs = &sc->work_bcs;

		if (sc->signature == cpu_to_le32(0)) {
			/*
			 * This is the first reply, so do not perform the check.
			 * Instead, remember the signature the device uses
			 * for future checks. But do not allow a nul.
			 */
			sc->signature = bcs->Signature;
			if (sc->signature == cpu_to_le32(0)) {
				ub_state_stat_counted(sc, cmd);
				return;
			}
		} else {
			if (bcs->Signature != sc->signature) {
				ub_state_stat_counted(sc, cmd);
				return;
			}
		}

		if (bcs->Tag != cmd->tag) {
			/*
			 * This usually happens when we disagree with the
			 * device's microcode about something. For instance,
			 * a few of them throw this after timeouts. They buffer
			 * commands and reply at commands we timed out before.
			 * Without flushing these replies we loop forever.
			 */
			ub_state_stat_counted(sc, cmd);
			return;
		}

		len = le32_to_cpu(bcs->Residue);
		if (len != cmd->len - cmd->act_len) {
			/*
			 * It is all right to transfer less, the caller has
			 * to check. But it's not all right if the device
			 * counts disagree with our counts.
			 */
			goto Bad_End;
		}

		switch (bcs->Status) {
		case US_BULK_STAT_OK:
			break;
		case US_BULK_STAT_FAIL:
			ub_state_sense(sc, cmd);
			return;
		case US_BULK_STAT_PHASE:
			goto Bad_End;
		default:
			printk(KERN_INFO "%s: unknown CSW status 0x%x\n",
			    sc->name, bcs->Status);
			ub_state_done(sc, cmd, -EINVAL);
			return;
		}

		/* Not zeroing error to preserve a babble indicator */
		if (cmd->error != 0) {
			ub_state_sense(sc, cmd);
			return;
		}
		cmd->state = UB_CMDST_DONE;
		ub_cmdq_pop(sc);
		(*cmd->done)(sc, cmd);

	} else if (cmd->state == UB_CMDST_SENSE) {
		ub_state_done(sc, cmd, -EIO);

	} else {
		printk(KERN_WARNING "%s: "
		    "wrong command state %d\n",
		    sc->name, cmd->state);
		ub_state_done(sc, cmd, -EINVAL);
		return;
	}
	return;

Bad_End: /* Little Excel is dead */
	ub_state_done(sc, cmd, -EIO);
}

/*
 * Factorization helper for the command state machine:
 * Initiate a data segment transfer.
 */
static void ub_data_start(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
{
	struct scatterlist *sg = &cmd->sgv[cmd->current_sg];
	int pipe;
	int rc;

	UB_INIT_COMPLETION(sc->work_done);

	if (cmd->dir == UB_DIR_READ)
		pipe = sc->recv_bulk_pipe;
	else
		pipe = sc->send_bulk_pipe;
	sc->last_pipe = pipe;
	usb_fill_bulk_urb(&sc->work_urb, sc->dev, pipe, sg_virt(sg),
	    sg->length, ub_urb_complete, sc);
	sc->work_urb.actual_length = 0;
	sc->work_urb.error_count = 0;
	sc->work_urb.status = 0;

	if ((rc = usb_submit_urb(&sc->work_urb, GFP_ATOMIC)) != 0) {
		/* XXX Clear stalls */
		ub_complete(&sc->work_done);
		ub_state_done(sc, cmd, rc);
		return;
	}

	sc->work_timer.expires = jiffies + UB_DATA_TIMEOUT;
	add_timer(&sc->work_timer);

	cmd->state = UB_CMDST_DATA;
}

/*
 * Factorization helper for the command state machine:
 * Finish the command.
 */
static void ub_state_done(struct ub_dev *sc, struct ub_scsi_cmd *cmd, int rc)
{

	cmd->error = rc;
	cmd->state = UB_CMDST_DONE;
	ub_cmdq_pop(sc);
	(*cmd->done)(sc, cmd);
}

/*
 * Factorization helper for the command state machine:
 * Submit a CSW read.
 */
static int __ub_state_stat(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
{
	int rc;

	UB_INIT_COMPLETION(sc->work_done);

	sc->last_pipe = sc->recv_bulk_pipe;
	usb_fill_bulk_urb(&sc->work_urb, sc->dev, sc->recv_bulk_pipe,
	    &sc->work_bcs, US_BULK_CS_WRAP_LEN, ub_urb_complete, sc);
	sc->work_urb.actual_length = 0;
	sc->work_urb.error_count = 0;
	sc->work_urb.status = 0;

	if ((rc = usb_submit_urb(&sc->work_urb, GFP_ATOMIC)) != 0) {
		/* XXX Clear stalls */
		ub_complete(&sc->work_done);
		ub_state_done(sc, cmd, rc);
		return -1;
	}

	sc->work_timer.expires = jiffies + UB_STAT_TIMEOUT;
	add_timer(&sc->work_timer);
	return 0;
}

/*
 * Factorization helper for the command state machine:
 * Submit a CSW read and go to STAT state.
 */
static void ub_state_stat(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
{

	if (__ub_state_stat(sc, cmd) != 0)
		return;

	cmd->stat_count = 0;
	cmd->state = UB_CMDST_STAT;
}

/*
 * Factorization helper for the command state machine:
 * Submit a CSW read and go to STAT state with counter (along [C] path).
 */
static void ub_state_stat_counted(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
{

	if (++cmd->stat_count >= 4) {
		ub_state_sense(sc, cmd);
		return;
	}

	if (__ub_state_stat(sc, cmd) != 0)
		return;

	cmd->state = UB_CMDST_STAT;
}

/*
 * Factorization helper for the command state machine:
 * Submit a REQUEST SENSE and go to SENSE state.
 */
static void ub_state_sense(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
{
	struct ub_scsi_cmd *scmd;
	struct scatterlist *sg;
	int rc;

	if (cmd->cdb[0] == REQUEST_SENSE) {
		rc = -EPIPE;
		goto error;
	}

	scmd = &sc->top_rqs_cmd;
	memset(scmd, 0, sizeof(struct ub_scsi_cmd));
	scmd->cdb[0] = REQUEST_SENSE;
	scmd->cdb[4] = UB_SENSE_SIZE;
	scmd->cdb_len = 6;
	scmd->dir = UB_DIR_READ;
	scmd->state = UB_CMDST_INIT;
	scmd->nsg = 1;
	sg = &scmd->sgv[0];
	sg_init_table(sg, UB_MAX_REQ_SG);
	sg_set_page(sg, virt_to_page(sc->top_sense), UB_SENSE_SIZE,
			(unsigned long)sc->top_sense & (PAGE_SIZE-1));
	scmd->len = UB_SENSE_SIZE;
	scmd->lun = cmd->lun;
	scmd->done = ub_top_sense_done;
	scmd->back = cmd;

	scmd->tag = sc->tagcnt++;

	cmd->state = UB_CMDST_SENSE;

	ub_cmdq_insert(sc, scmd);
	return;

error:
	ub_state_done(sc, cmd, rc);
}

/*
 * A helper for the command's state machine:
 * Submit a stall clear.
 */
static int ub_submit_clear_stall(struct ub_dev *sc, struct ub_scsi_cmd *cmd,
    int stalled_pipe)
{
	int endp;
	struct usb_ctrlrequest *cr;
	int rc;

	endp = usb_pipeendpoint(stalled_pipe);
	if (usb_pipein (stalled_pipe))
		endp |= USB_DIR_IN;

	cr = &sc->work_cr;
	cr->bRequestType = USB_RECIP_ENDPOINT;
	cr->bRequest = USB_REQ_CLEAR_FEATURE;
	cr->wValue = cpu_to_le16(USB_ENDPOINT_HALT);
	cr->wIndex = cpu_to_le16(endp);
	cr->wLength = cpu_to_le16(0);

	UB_INIT_COMPLETION(sc->work_done);

	usb_fill_control_urb(&sc->work_urb, sc->dev, sc->send_ctrl_pipe,
	    (unsigned char*) cr, NULL, 0, ub_urb_complete, sc);
	sc->work_urb.actual_length = 0;
	sc->work_urb.error_count = 0;
	sc->work_urb.status = 0;

	if ((rc = usb_submit_urb(&sc->work_urb, GFP_ATOMIC)) != 0) {
		ub_complete(&sc->work_done);
		return rc;
	}

	sc->work_timer.expires = jiffies + UB_CTRL_TIMEOUT;
	add_timer(&sc->work_timer);
	return 0;
}