--- /dev/null
+/* 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);
Code Review / kvmfornfv.git / blobdiff