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author | Srikant Patnaik | 2015-01-11 12:28:04 +0530 |
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committer | Srikant Patnaik | 2015-01-11 12:28:04 +0530 |
commit | 871480933a1c28f8a9fed4c4d34d06c439a7a422 (patch) | |
tree | 8718f573808810c2a1e8cb8fb6ac469093ca2784 /drivers/usb/storage/protocol.c | |
parent | 9d40ac5867b9aefe0722bc1f110b965ff294d30d (diff) | |
download | FOSSEE-netbook-kernel-source-871480933a1c28f8a9fed4c4d34d06c439a7a422.tar.gz FOSSEE-netbook-kernel-source-871480933a1c28f8a9fed4c4d34d06c439a7a422.tar.bz2 FOSSEE-netbook-kernel-source-871480933a1c28f8a9fed4c4d34d06c439a7a422.zip |
Moved, renamed, and deleted files
The original directory structure was scattered and unorganized.
Changes are basically to make it look like kernel structure.
Diffstat (limited to 'drivers/usb/storage/protocol.c')
-rw-r--r-- | drivers/usb/storage/protocol.c | 220 |
1 files changed, 220 insertions, 0 deletions
diff --git a/drivers/usb/storage/protocol.c b/drivers/usb/storage/protocol.c new file mode 100644 index 00000000..82dd8347 --- /dev/null +++ b/drivers/usb/storage/protocol.c @@ -0,0 +1,220 @@ +/* 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; + struct scatterlist *sg = *sgptr; + + /* 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. + */ + + if (!sg) + sg = scsi_sglist(srb); + + /* 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 **sgptr values for the next loop. + */ + cnt = 0; + while (cnt < buflen && sg) { + struct page *page = sg_page(sg) + + ((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; + sg = sg_next(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; + } + } + *sgptr = sg; + + /* Return the amount actually transferred */ + 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); |