src/add-ons/kernel/bus_managers/ata/ATAHelper.cpp

   1 /*
   2  * Copyright 2009, Michael Lotz, mmlr@mlotz.ch.
   3  * Copyright 2004-2007, Axel Dörfler, axeld@pinc-software.de.
   4  * Copyright 2002/03, Thomas Kurschel. All rights reserved.
   5  *
   6  * Distributed under the terms of the MIT License.
   7  */
   8
   9 #include "ATAPrivate.h"
  10
  11 #include <vm/vm.h>
  12 #include <string.h>
  13
  14
  15 /*!     Copy data between ccb data and buffer
  16         ccb                     - ccb to copy data from/to
  17         offset                  - offset of data in ccb
  18         allocation_length- limit of ccb's data buffer according to CDB
  19         buffer                  - data to copy data from/to
  20         size                    - number of bytes to copy
  21         to_buffer               - true: copy from ccb to buffer
  22                                           false: copy from buffer to ccb
  23         return: true, if data of ccb was large enough
  24 */
  25 bool
  26 copy_sg_data(scsi_ccb *ccb, uint offset, uint allocationLength,
  27         void *buffer, int size, bool toBuffer)
  28 {
  29         const physical_entry *sgList = ccb->sg_list;
  30         int sgCount = ccb->sg_count;
  31
  32         // skip unused S/G entries
  33         while (sgCount > 0 && offset >= sgList->size) {
  34                 offset -= sgList->size;
  35                 ++sgList;
  36                 --sgCount;
  37         }
  38
  39         if (sgCount == 0)
  40                 return false;
  41
  42         // remaining bytes we are allowed to copy from/to ccb
  43         int requestSize = MIN(allocationLength, ccb->data_length) - offset;
  44
  45         // copy one S/G entry at a time
  46         for (; size > 0 && requestSize > 0 && sgCount > 0; ++sgList, --sgCount) {
  47                 size_t bytes;
  48
  49                 bytes = MIN(size, requestSize);
  50                 bytes = MIN(bytes, sgList->size);
  51
  52                 if (toBuffer) {
  53                         vm_memcpy_from_physical(buffer, sgList->address + offset, bytes,
  54                                 false);
  55                 } else {
  56                         vm_memcpy_to_physical(sgList->address + offset, buffer, bytes,
  57                                 false);
  58                 }
  59
  60                 buffer = (char *)buffer + bytes;
  61                 size -= bytes;
  62                 offset = 0;
  63         }
  64
  65         return size == 0;
  66 }
  67
  68
  69 void
  70 swap_words(void *data, size_t size)
  71 {
  72         uint16 *word = (uint16 *)data;
  73         size_t count = size / 2;
  74         while (count--) {
  75                 *word = B_BENDIAN_TO_HOST_INT16(*word);
  76                 word++;
  77         }
  78 }