file_storage.c

LINUX2.4.18内核下的usb GADGET驱动程序

#endif
			value = populate_config_buf(fsg->gadget->speed,
					req->buf,
					ctrl->wValue >> 8,
					ctrl->wValue & 0xff);
			if (value >= 0)
				value = min(ctrl->wLength, (u16) value);
			break;

		case USB_DT_STRING:
			VDBG(fsg, "get string descriptor\n");

			/* wIndex == language code */
			value = usb_gadget_get_string(&stringtab,
					ctrl->wValue & 0xff, req->buf);
			if (value >= 0)
				value = min(ctrl->wLength, (u16) value);
			break;
		}
		break;

	/* One config, two speeds */
	case USB_REQ_SET_CONFIGURATION:
		if (ctrl->bRequestType != (USB_DIR_OUT | USB_TYPE_STANDARD |
				USB_RECIP_DEVICE))
			break;
		VDBG(fsg, "set configuration\n");
		if (ctrl->wValue == CONFIG_VALUE || ctrl->wValue == 0) {
			fsg->new_config = ctrl->wValue;

			/* Raise an exception to wipe out previous transaction
			 * state (queued bufs, etc) and set the new config. */
			raise_exception(fsg, FSG_STATE_CONFIG_CHANGE);
			value = DELAYED_STATUS;
		}
		break;
	case USB_REQ_GET_CONFIGURATION:
		if (ctrl->bRequestType != (USB_DIR_IN | USB_TYPE_STANDARD |
				USB_RECIP_DEVICE))
			break;
		VDBG(fsg, "get configuration\n");
		*(u8 *) req->buf = fsg->config;
		value = min(ctrl->wLength, (u16) 1);
		break;

	case USB_REQ_SET_INTERFACE:
		if (ctrl->bRequestType != (USB_DIR_OUT| USB_TYPE_STANDARD |
				USB_RECIP_INTERFACE))
			break;
		if (fsg->config && ctrl->wIndex == 0) {

			/* Raise an exception to wipe out previous transaction
			 * state (queued bufs, etc) and install the new
			 * interface altsetting. */
			raise_exception(fsg, FSG_STATE_INTERFACE_CHANGE);
			value = DELAYED_STATUS;
		}
		break;
	case USB_REQ_GET_INTERFACE:
		if (ctrl->bRequestType != (USB_DIR_IN | USB_TYPE_STANDARD |
				USB_RECIP_INTERFACE))
			break;
		if (!fsg->config)
			break;
		if (ctrl->wIndex != 0) {
			value = -EDOM;
			break;
		}
		VDBG(fsg, "get interface\n");
		*(u8 *) req->buf = 0;
		value = min(ctrl->wLength, (u16) 1);
		break;

	default:
		VDBG(fsg,
			"unknown control req %02x.%02x v%04x i%04x l%u\n",
			ctrl->bRequestType, ctrl->bRequest,
			ctrl->wValue, ctrl->wIndex, ctrl->wLength);
	}

	return value;
}


static int fsg_setup(struct usb_gadget *gadget,
		const struct usb_ctrlrequest *ctrl)
{
	struct fsg_dev		*fsg = get_gadget_data(gadget);
	int			rc;

	++fsg->ep0_req_tag;		// Record arrival of a new request
	fsg->ep0req->context = NULL;
	fsg->ep0req->length = 0;
	dump_msg(fsg, "ep0-setup", (u8 *) ctrl, sizeof(*ctrl));

	if ((ctrl->bRequestType & USB_TYPE_MASK) == USB_TYPE_CLASS)
		rc = class_setup_req(fsg, ctrl);
	else
		rc = standard_setup_req(fsg, ctrl);

	/* Respond with data/status or defer until later? */
	if (rc >= 0 && rc != DELAYED_STATUS) {
		fsg->ep0req->length = rc;
		fsg->ep0req_name = (ctrl->bRequestType & USB_DIR_IN ?
				"ep0-in" : "ep0-out");
		rc = ep0_queue(fsg);
	}

	/* Device either stalls (rc < 0) or reports success */
	return rc;
}


/*-------------------------------------------------------------------------*/

/* All the following routines run in process context */


/* Use this for bulk or interrupt transfers, not ep0 */
static void start_transfer(struct fsg_dev *fsg, struct usb_ep *ep,
		struct usb_request *req, volatile int *pbusy,
		volatile enum fsg_buffer_state *state)
{
	int	rc;

	if (ep == fsg->bulk_in)
		dump_msg(fsg, "bulk-in", req->buf, req->length);
	else if (ep == fsg->intr_in)
		dump_msg(fsg, "intr-in", req->buf, req->length);
	*pbusy = 1;
	*state = BUF_STATE_BUSY;
	rc = usb_ep_queue(ep, req, GFP_KERNEL);
	if (rc != 0) {
		*pbusy = 0;
		*state = BUF_STATE_EMPTY;

		/* We can't do much more than wait for a reset */

		/* Note: currently the net2280 driver fails zero-length
		 * submissions if DMA is enabled. */
		if (rc != -ESHUTDOWN && !(rc == -EOPNOTSUPP &&
						req->length == 0))
			WARN(fsg, "error in submission: %s --> %d\n",
					ep->name, rc);
	}
}


static int sleep_thread(struct fsg_dev *fsg)
{
	int	rc;

	/* Wait until a signal arrives or we are woken up */
	rc = wait_event_interruptible(fsg->thread_wqh,
			fsg->thread_wakeup_needed);
	fsg->thread_wakeup_needed = 0;
	return (rc ? -EINTR : 0);
}


/*-------------------------------------------------------------------------*/

static int do_read(struct fsg_dev *fsg)
{
	struct lun		*curlun = fsg->curlun;
	u32			lba;
	struct fsg_buffhd	*bh;
	int			rc;
	u32			amount_left;
	loff_t			file_offset, file_offset_tmp;
	unsigned int		amount;
	unsigned int		partial_page;
	ssize_t			nread;

	/* Get the starting Logical Block Address and check that it's
	 * not too big */
	if (fsg->cmnd[0] == SC_READ_6)
		lba = (fsg->cmnd[1] << 16) | get_be16(&fsg->cmnd[2]);
	else {
		lba = get_be32(&fsg->cmnd[2]);

		/* We allow DPO (Disable Page Out = don't save data in the
		 * cache) and FUA (Force Unit Access = don't read from the
		 * cache), but we don't implement them. */
		if ((fsg->cmnd[1] & ~0x18) != 0) {
			curlun->sense_data = SS_INVALID_FIELD_IN_CDB;
			return -EINVAL;
		}
	}
	if (lba >= curlun->num_sectors) {
		curlun->sense_data = SS_LOGICAL_BLOCK_ADDRESS_OUT_OF_RANGE;
		return -EINVAL;
	}
	file_offset = ((loff_t) lba) << 9;

	/* Carry out the file reads */
	amount_left = fsg->data_size_from_cmnd;
	if (unlikely(amount_left == 0))
		return -EIO;		// No default reply

	for (;;) {

		/* Figure out how much we need to read:
		 * Try to read the remaining amount.
		 * But don't read more than the buffer size.
		 * And don't try to read past the end of the file.
		 * Finally, if we're not at a page boundary, don't read past
		 *	the next page.
		 * If this means reading 0 then we were asked to read past
		 *	the end of file. */
		amount = min((unsigned int) amount_left, mod_data.buflen);
		amount = min((loff_t) amount,
				curlun->file_length - file_offset);
		partial_page = file_offset & (PAGE_CACHE_SIZE - 1);
		if (partial_page > 0)
			amount = min(amount, (unsigned int) PAGE_CACHE_SIZE -
					partial_page);

		/* Wait for the next buffer to become available */
		bh = fsg->next_buffhd_to_fill;
		while (bh->state != BUF_STATE_EMPTY) {
			if ((rc = sleep_thread(fsg)) != 0)
				return rc;
		}

		/* If we were asked to read past the end of file,
		 * end with an empty buffer. */
		if (amount == 0) {
			curlun->sense_data =
					SS_LOGICAL_BLOCK_ADDRESS_OUT_OF_RANGE;
			curlun->sense_data_info = file_offset >> 9;
			bh->inreq->length = 0;
			bh->state = BUF_STATE_FULL;
			break;
		}

		/* Perform the read */
		file_offset_tmp = file_offset;
		nread = curlun->filp->f_op->read(curlun->filp,
				(char *) bh->buf,
				amount, &file_offset_tmp);
		VLDBG(curlun, "file read %u @ %llu -> %d\n", amount,
				(unsigned long long) file_offset,
				(int) nread);
		if (signal_pending(current))
			return -EINTR;

		if (nread < 0) {
			LDBG(curlun, "error in file read: %d\n",
					(int) nread);
			nread = 0;
		} else if (nread < amount) {
			LDBG(curlun, "partial file read: %d/%u\n",
					(int) nread, amount);
			nread -= (nread & 511);	// Round down to a block
		}
		file_offset  += nread;
		amount_left  -= nread;
		fsg->residue -= nread;
		bh->inreq->length = nread;
		bh->state = BUF_STATE_FULL;

		/* If an error occurred, report it and its position */
		if (nread < amount) {
			curlun->sense_data = SS_UNRECOVERED_READ_ERROR;
			curlun->sense_data_info = file_offset >> 9;
			break;
		}

		if (amount_left == 0)
			break;		// No more left to read

		/* Send this buffer and go read some more */
		bh->inreq->zero = 0;
		start_transfer(fsg, fsg->bulk_in, bh->inreq,
				&bh->inreq_busy, &bh->state);
		fsg->next_buffhd_to_fill = bh->next;
	}

	return -EIO;		// No default reply
}


/*-------------------------------------------------------------------------*/

static int do_write(struct fsg_dev *fsg)
{
	struct lun		*curlun = fsg->curlun;
	u32			lba;
	struct fsg_buffhd	*bh;
	int			get_some_more;
	u32			amount_left_to_req, amount_left_to_write;
	loff_t			usb_offset, file_offset, file_offset_tmp;
	unsigned int		amount;
	unsigned int		partial_page;
	ssize_t			nwritten;
	int			rc;

	if (curlun->ro) {
		curlun->sense_data = SS_WRITE_PROTECTED;
		return -EINVAL;
	}
	curlun->filp->f_flags &= ~O_SYNC;	// Default is not to wait

	/* Get the starting Logical Block Address and check that it's
	 * not too big */
	if (fsg->cmnd[0] == SC_WRITE_6)
		lba = (fsg->cmnd[1] << 16) | get_be16(&fsg->cmnd[2]);
	else {
		lba = get_be32(&fsg->cmnd[2]);

		/* We allow DPO (Disable Page Out = don't save data in the
		 * cache) and FUA (Force Unit Access = write directly to the
		 * medium).  We don't implement DPO; we implement FUA by
		 * performing synchronous output. */
		if ((fsg->cmnd[1] & ~0x18) != 0) {
			curlun->sense_data = SS_INVALID_FIELD_IN_CDB;
			return -EINVAL;
		}
		if (fsg->cmnd[1] & 0x08)	// FUA
			curlun->filp->f_flags |= O_SYNC;
	}
	if (lba >= curlun->num_sectors) {
		curlun->sense_data = SS_LOGICAL_BLOCK_ADDRESS_OUT_OF_RANGE;
		return -EINVAL;
	}

	/* Carry out the file writes */
	get_some_more = 1;
	file_offset = usb_offset = ((loff_t) lba) << 9;
	amount_left_to_req = amount_left_to_write = fsg->data_size_from_cmnd;

	while (amount_left_to_write > 0) {

		/* Queue a request for more data from the host */
		bh = fsg->next_buffhd_to_fill;
		if (bh->state == BUF_STATE_EMPTY && get_some_more) {

			/* Figure out how much we want to get:
			 * Try to get the remaining amount.
			 * But don't get more than the buffer size.
			 * And don't try to go past the end of the file.
			 * If we're not at a page boundary,
			 *	don't go past the next page.
			 * If this means getting 0, then we were asked
			 *	to write past the end of file.
			 * Finally, round down to a block boundary. */
			amount = min(amount_left_to_req, mod_data.buflen);
			amount = min((loff_t) amount, curlun->file_length -
					usb_offset);
			partial_page = usb_offset & (PAGE_CACHE_SIZE - 1);
			if (partial_page > 0)
				amount = min(amount,
	(unsigned int) PAGE_CACHE_SIZE - partial_page);

			if (amount == 0) {
				get_some_more = 0;
				curlun->sense_data =
					SS_LOGICAL_BLOCK_ADDRESS_OUT_OF_RANGE;
				curlun->sense_data_info = usb_offset >> 9;
				continue;
			}
			amount -= (amount & 511);
			if (amount == 0) {

				/* Why were we were asked to transfer a
				 * partial block? */
				get_some_more = 0;
				continue;
			}

			/* Get the next buffer */
			usb_offset += amount;
			fsg->usb_amount_left -= amount;
			amount_left_to_req -= amount;
			if (amount_left_to_req == 0)
				get_some_more = 0;

			/* amount is always divisible by 512, hence by
			 * the bulk-out maxpacket size */
			bh->outreq->length = bh->bulk_out_intended_length =
					amount;
			start_transfer(fsg, fsg->bulk_out, bh->outreq,
					&bh->outreq_busy, &bh->state);
			fsg->next_buffhd_to_fill = bh->next;
			continue;
		}

		/* Write the received data to the backing file */
		bh = fsg->next_buffhd_to_drain;
		if (bh->state == BUF_STATE_EMPTY && !get_some_more)
			break;			// We stopped early
		if (bh->state == BUF_STATE_FULL) {
			fsg->next_buffhd_to_drain = bh->next;
			bh->state = BUF_STATE_EMPTY;

			/* Did something go wrong with the transfer? */
			if (bh->outreq->status != 0) {
				curlun->sense_data = SS_COMMUNICATION_FAILURE;
				curlun->sense_data_info = file_offset >> 9;
				break;
			}

			amount = bh->outreq->actual;
			if (curlun->file_length - file_offset < amount) {
				LERROR(curlun,
	"write %u @ %llu beyond end %llu\n",
	amount, (unsigned long long) file_offset,
	(unsigned long long) curlun->file_length);
				amount = curlun->file_length - file_offset;
			}

			/* Perform the write */
			file_offset_tmp = file_offset;
			nwritten = curlun->filp->f_op->write(curlun->filp,
					(char *) bh->buf,
					amount, &file_offset_tmp);
			VLDBG(curlun, "file write %u @ %llu -> %d\n", amount,
					(unsigned long long) file_offset,
					(int) nwritten);
			if (signal_pending(current))
				return -EINTR;		// Interrupted!

			if (nwritten < 0) {
				LDBG(curlun, "error in file write: %d\n",
						(int) nwritten);
				nwritten = 0;
			} else if (nwritten < amount) {
				LDBG(curlun, "partial file write: %d/%u\n",
						(int) nwritten, amount);
				nwritten -= (nwritten & 511);
						// Round down to a block
			}
			file_offset += nwritten;
			amount_left_to_write -= nwritten;
			fsg->residue -= nwritten;

			/* If an error occurred, report it and its position */
			if (nwritten < amount) {
				curlun->sense_data = SS_WRITE_ERROR;
				curlun->sense_data_info = file_offset >> 9;
				break;
			}

			/* Did the host decide to stop early? */
			if (bh->outreq->actual != bh->outreq->length) {
				fsg->short_packet_received = 1;
				break;
			}
			continue;
		}