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(I'm so sorry!) Linux kernel mirror (for testing) git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel os linux
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123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150151152153154155156157158159160161162163164165166167168169170171172173174175176177178179180181// SPDX-License-Identifier: GPL-2.0+/* * 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. */
#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(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);