1 files changed, 193 insertions, 0 deletions
diff --git a/drivers/usb/storage/protocol.c b/drivers/usb/storage/protocol.c
new file mode 100644
index 000000000..12e3c2fac
--- /dev/null
+++ b/drivers/usb/storage/protocol.c
@@ -0,0 +1,193 @@
+/* Driver for USB Mass Storage compliant devices
+ *
+ * Current development and maintenance by:
+ *   (c) 1999-2002 Matthew Dharm (mdharm-usb@one-eyed-alien.net)
+ *
+ * Developed with the assistance of:
+ *   (c) 2000 David L. Brown, Jr. (usb-storage@davidb.org)
+ *   (c) 2002 Alan Stern (stern@rowland.org)
+ *
+ * Initial work by:
+ *   (c) 1999 Michael Gee (michael@linuxspecific.com)
+ *
+ * This driver is based on the 'USB Mass Storage Class' document. This
+ * describes in detail the protocol used to communicate with such
+ * devices.  Clearly, the designers had SCSI and ATAPI commands in
+ * mind when they created this document.  The commands are all very
+ * similar to commands in the SCSI-II and ATAPI specifications.
+ *
+ * It is important to note that in a number of cases this class
+ * exhibits class-specific exemptions from the USB specification.
+ * Notably the usage of NAK, STALL and ACK differs from the norm, in
+ * that they are used to communicate wait, failed and OK on commands.
+ *
+ * Also, for certain devices, the interrupt endpoint is used to convey
+ * status of a command.
+ *
+ * Please see http://www.one-eyed-alien.net/~mdharm/linux-usb for more
+ * information about this driver.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; either version 2, or (at your option) any
+ * later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+#include <linux/highmem.h>
+#include <linux/export.h>
+#include <scsi/scsi.h>
+#include <scsi/scsi_cmnd.h>
+
+#include "usb.h"
+#include "protocol.h"
+#include "debug.h"
+#include "scsiglue.h"
+#include "transport.h"
+
+/***********************************************************************
+ * Protocol routines
+ ***********************************************************************/
+
+void usb_stor_pad12_command(struct scsi_cmnd *srb, struct us_data *us)
+{
+	/*
+	 * Pad the SCSI command with zeros out to 12 bytes.  If the
+	 * command already is 12 bytes or longer, leave it alone.
+	 *
+	 * NOTE: This only works because a scsi_cmnd struct field contains
+	 * a unsigned char cmnd[16], so we know we have storage available
+	 */
+	for (; srb->cmd_len < 12; srb->cmd_len++)
+		srb->cmnd[srb->cmd_len] = 0;
+
+	/* send the command to the transport layer */
+	usb_stor_invoke_transport(srb, us);
+}
+
+void usb_stor_ufi_command(struct scsi_cmnd *srb, struct us_data *us)
+{
+	/* fix some commands -- this is a form of mode translation
+	 * UFI devices only accept 12 byte long commands
+	 *
+	 * NOTE: This only works because a scsi_cmnd struct field contains
+	 * a unsigned char cmnd[16], so we know we have storage available
+	 */
+
+	/* Pad the ATAPI command with zeros */
+	for (; srb->cmd_len < 12; srb->cmd_len++)
+		srb->cmnd[srb->cmd_len] = 0;
+
+	/* set command length to 12 bytes (this affects the transport layer) */
+	srb->cmd_len = 12;
+
+	/* XXX We should be constantly re-evaluating the need for these */
+
+	/* determine the correct data length for these commands */
+	switch (srb->cmnd[0]) {
+
+		/* for INQUIRY, UFI devices only ever return 36 bytes */
+	case INQUIRY:
+		srb->cmnd[4] = 36;
+		break;
+
+		/* again, for MODE_SENSE_10, we get the minimum (8) */
+	case MODE_SENSE_10:
+		srb->cmnd[7] = 0;
+		srb->cmnd[8] = 8;
+		break;
+
+		/* for REQUEST_SENSE, UFI devices only ever return 18 bytes */
+	case REQUEST_SENSE:
+		srb->cmnd[4] = 18;
+		break;
+	} /* end switch on cmnd[0] */
+
+	/* send the command to the transport layer */
+	usb_stor_invoke_transport(srb, us);
+}
+
+void usb_stor_transparent_scsi_command(struct scsi_cmnd *srb,
+				       struct us_data *us)
+{
+	/* send the command to the transport layer */
+	usb_stor_invoke_transport(srb, us);
+}
+EXPORT_SYMBOL_GPL(usb_stor_transparent_scsi_command);
+
+/***********************************************************************
+ * Scatter-gather transfer buffer access routines
+ ***********************************************************************/
+
+/* Copy a buffer of length buflen to/from the srb's transfer buffer.
+ * Update the **sgptr and *offset variables so that the next copy will
+ * pick up from where this one left off.
+ */
+unsigned int usb_stor_access_xfer_buf(unsigned char *buffer,
+	unsigned int buflen, struct scsi_cmnd *srb, struct scatterlist **sgptr,
+	unsigned int *offset, enum xfer_buf_dir dir)
+{
+	unsigned int cnt = 0;
+	struct scatterlist *sg = *sgptr;
+	struct sg_mapping_iter miter;
+	unsigned int nents = scsi_sg_count(srb);
+
+	if (sg)
+		nents = sg_nents(sg);
+	else
+		sg = scsi_sglist(srb);
+
+	sg_miter_start(&miter, sg, nents, dir == FROM_XFER_BUF ?
+		SG_MITER_FROM_SG: SG_MITER_TO_SG);
+
+	if (!sg_miter_skip(&miter, *offset))
+		return cnt;
+
+	while (sg_miter_next(&miter) && cnt < buflen) {
+		unsigned int len = min_t(unsigned int, miter.length,
+				buflen - cnt);
+
+		if (dir == FROM_XFER_BUF)
+			memcpy(buffer + cnt, miter.addr, len);
+		else
+			memcpy(miter.addr, buffer + cnt, len);
+
+		if (*offset + len < miter.piter.sg->length) {
+			*offset += len;
+			*sgptr = miter.piter.sg;
+		} else {
+			*offset = 0;
+			*sgptr = sg_next(miter.piter.sg);
+		}
+		cnt += len;
+	}
+	sg_miter_stop(&miter);
+
+	return cnt;
+}
+EXPORT_SYMBOL_GPL(usb_stor_access_xfer_buf);
+
+/* Store the contents of buffer into srb's transfer buffer and set the
+ * SCSI residue.
+ */
+void usb_stor_set_xfer_buf(unsigned char *buffer,
+	unsigned int buflen, struct scsi_cmnd *srb)
+{
+	unsigned int offset = 0;
+	struct scatterlist *sg = NULL;
+
+	buflen = min(buflen, scsi_bufflen(srb));
+	buflen = usb_stor_access_xfer_buf(buffer, buflen, srb, &sg, &offset,
+			TO_XFER_BUF);
+	if (buflen < scsi_bufflen(srb))
+		scsi_set_resid(srb, scsi_bufflen(srb) - buflen);
+}
+EXPORT_SYMBOL_GPL(usb_stor_set_xfer_buf);