drivers/usb/storage/protocol.h

   1 // SPDX-License-Identifier: GPL-2.0+
   2 /*
   3  * Driver for USB Mass Storage compliant devices
   4  * Protocol Functions Header File
   5  *
   6  * Current development and maintenance by:
   7  *   (c) 1999, 2000 Matthew Dharm (mdharm-usb@one-eyed-alien.net)
   8  *
   9  * This driver is based on the 'USB Mass Storage Class' document. This
  10  * describes in detail the protocol used to communicate with such
  11  * devices.  Clearly, the designers had SCSI and ATAPI commands in
  12  * mind when they created this document.  The commands are all very
  13  * similar to commands in the SCSI-II and ATAPI specifications.
  14  *
  15  * It is important to note that in a number of cases this class
  16  * exhibits class-specific exemptions from the USB specification.
  17  * Notably the usage of NAK, STALL and ACK differs from the norm, in
  18  * that they are used to communicate wait, failed and OK on commands.
  19  *
  20  * Also, for certain devices, the interrupt endpoint is used to convey
  21  * status of a command.
  22  *
  23  * Please see http://www.one-eyed-alien.net/~mdharm/linux-usb for more
  24  * information about this driver.
  25  */
  26
  27 #ifndef _PROTOCOL_H_
  28 #define _PROTOCOL_H_
  29
  30 /* Protocol handling routines */
  31 extern void usb_stor_pad12_command(struct scsi_cmnd*, struct us_data*);
  32 extern void usb_stor_ufi_command(struct scsi_cmnd*, struct us_data*);
  33 extern void usb_stor_transparent_scsi_command(struct scsi_cmnd*,
  34                 struct us_data*);
  35
  36 /* struct scsi_cmnd transfer buffer access utilities */
  37 enum xfer_buf_dir       {TO_XFER_BUF, FROM_XFER_BUF};
  38
  39 extern unsigned int usb_stor_access_xfer_buf(unsigned char *buffer,
  40         unsigned int buflen, struct scsi_cmnd *srb, struct scatterlist **,
  41         unsigned int *offset, enum xfer_buf_dir dir);
  42
  43 extern void usb_stor_set_xfer_buf(unsigned char *buffer,
  44         unsigned int buflen, struct scsi_cmnd *srb);
  45 #endif