1 files changed, 254 insertions, 0 deletions
diff --git a/drivers/usb/storage/protocol.c b/drivers/usb/storage/protocol.c
new file mode 100644
index 00000000000..9ad30428d2d
--- /dev/null
+++ b/drivers/usb/storage/protocol.c
@@ -0,0 +1,254 @@
+/* Driver for USB Mass Storage compliant devices
+ *
+ * $Id: protocol.c,v 1.14 2002/04/22 03:39:43 mdharm Exp $
+ *
+ * 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 <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_qic157_command(struct scsi_cmnd *srb, struct us_data *us)
+{
+	/* Pad the ATAPI command with zeros 
+	 *
+	 * 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;
+
+	/* set command length to 12 bytes */
+	srb->cmd_len = 12;
+
+	/* send the command to the transport layer */
+	usb_stor_invoke_transport(srb, us);
+}
+
+void usb_stor_ATAPI_command(struct scsi_cmnd *srb, struct us_data *us)
+{
+	/* Pad the ATAPI command with zeros 
+	 *
+	 * 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 */
+	srb->cmd_len = 12;
+
+	/* 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);
+}
+
+/***********************************************************************
+ * Scatter-gather transfer buffer access routines
+ ***********************************************************************/
+
+/* Copy a buffer of length buflen to/from the srb's transfer buffer.
+ * (Note: for scatter-gather transfers (srb->use_sg > 0), srb->request_buffer
+ * points to a list of s-g entries and we ignore srb->request_bufflen.
+ * For non-scatter-gather transfers, srb->request_buffer points to the
+ * transfer buffer itself and srb->request_bufflen is the buffer's length.)
+ * Update the *index 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, unsigned int *index,
+	unsigned int *offset, enum xfer_buf_dir dir)
+{
+	unsigned int cnt;
+
+	/* If not using scatter-gather, just transfer the data directly.
+	 * Make certain it will fit in the available buffer space. */
+	if (srb->use_sg == 0) {
+		if (*offset >= srb->request_bufflen)
+			return 0;
+		cnt = min(buflen, srb->request_bufflen - *offset);
+		if (dir == TO_XFER_BUF)
+			memcpy((unsigned char *) srb->request_buffer + *offset,
+					buffer, cnt);
+		else
+			memcpy(buffer, (unsigned char *) srb->request_buffer +
+					*offset, cnt);
+		*offset += cnt;
+
+	/* Using scatter-gather.  We have to go through the list one entry
+	 * at a time.  Each s-g entry contains some number of pages, and
+	 * each page has to be kmap()'ed separately.  If the page is already
+	 * in kernel-addressable memory then kmap() will return its address.
+	 * If the page is not directly accessible -- such as a user buffer
+	 * located in high memory -- then kmap() will map it to a temporary
+	 * position in the kernel's virtual address space. */
+	} else {
+		struct scatterlist *sg =
+				(struct scatterlist *) srb->request_buffer
+				+ *index;
+
+		/* This loop handles a single s-g list entry, which may
+		 * include multiple pages.  Find the initial page structure
+		 * and the starting offset within the page, and update
+		 * the *offset and *index values for the next loop. */
+		cnt = 0;
+		while (cnt < buflen && *index < srb->use_sg) {
+			struct page *page = sg->page +
+					((sg->offset + *offset) >> PAGE_SHIFT);
+			unsigned int poff =
+					(sg->offset + *offset) & (PAGE_SIZE-1);
+			unsigned int sglen = sg->length - *offset;
+
+			if (sglen > buflen - cnt) {
+
+				/* Transfer ends within this s-g entry */
+				sglen = buflen - cnt;
+				*offset += sglen;
+			} else {
+
+				/* Transfer continues to next s-g entry */
+				*offset = 0;
+				++*index;
+				++sg;
+			}
+
+			/* Transfer the data for all the pages in this
+			 * s-g entry.  For each page: call kmap(), do the
+			 * transfer, and call kunmap() immediately after. */
+			while (sglen > 0) {
+				unsigned int plen = min(sglen, (unsigned int)
+						PAGE_SIZE - poff);
+				unsigned char *ptr = kmap(page);
+
+				if (dir == TO_XFER_BUF)
+					memcpy(ptr + poff, buffer + cnt, plen);
+				else
+					memcpy(buffer + cnt, ptr + poff, plen);
+				kunmap(page);
+
+				/* Start at the beginning of the next page */
+				poff = 0;
+				++page;
+				cnt += plen;
+				sglen -= plen;
+			}
+		}
+	}
+
+	/* Return the amount actually transferred */
+	return cnt;
+}
+
+/* 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 index = 0, offset = 0;
+
+	usb_stor_access_xfer_buf(buffer, buflen, srb, &index, &offset,
+			TO_XFER_BUF);
+	if (buflen < srb->request_bufflen)
+		srb->resid = srb->request_bufflen - buflen;
+}