iokit/Kernel/IOMemoryCursor.cpp

   1 /*
   2  * Copyright (c) 1998-2000 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
   5  *
   6  * This file contains Original Code and/or Modifications of Original Code
   7  * as defined in and that are subject to the Apple Public Source License
   8  * Version 2.0 (the 'License'). You may not use this file except in
   9  * compliance with the License. The rights granted to you under the License
  10  * may not be used to create, or enable the creation or redistribution of,
  11  * unlawful or unlicensed copies of an Apple operating system, or to
  12  * circumvent, violate, or enable the circumvention or violation of, any
  13  * terms of an Apple operating system software license agreement.
  14  *
  15  * Please obtain a copy of the License at
  16  * http://www.opensource.apple.com/apsl/ and read it before using this file.
  17  *
  18  * The Original Code and all software distributed under the License are
  19  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  20  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  21  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  22  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  23  * Please see the License for the specific language governing rights and
  24  * limitations under the License.
  25  *
  26  * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
  27  */
  28 /* IOMemoryCursor.cpp created by wgulland on 1999-3-02 */
  29
  30 #include <IOKit/assert.h>
  31 #include <IOKit/IOLib.h>
  32 #include <IOKit/IOMemoryCursor.h>
  33 #include <IOKit/IOMemoryDescriptor.h>
  34 #include <libkern/OSByteOrder.h>
  35
  36 /**************************** class IOMemoryCursor ***************************/
  37
  38 #undef super
  39 #define super OSObject
  40 OSDefineMetaClassAndStructors(IOMemoryCursor, OSObject)
  41
  42 IOMemoryCursor *
  43 IOMemoryCursor::withSpecification(SegmentFunction  inSegFunc,
  44                                   IOPhysicalLength inMaxSegmentSize,
  45                                   IOPhysicalLength inMaxTransferSize,
  46                                   IOPhysicalLength inAlignment)
  47 {
  48     IOMemoryCursor * me = new IOMemoryCursor;
  49
  50     if (me && !me->initWithSpecification(inSegFunc,
  51                                          inMaxSegmentSize,
  52                                          inMaxTransferSize,
  53                                          inAlignment))
  54     {
  55         me->release();
  56         return 0;
  57     }
  58
  59     return me;
  60 }
  61
  62 /* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
  63
  64 bool
  65 IOMemoryCursor::initWithSpecification(SegmentFunction  inSegFunc,
  66                                       IOPhysicalLength inMaxSegmentSize,
  67                                       IOPhysicalLength inMaxTransferSize,
  68                                       IOPhysicalLength inAlignment)
  69 {
  70 // @@@ gvdl: Remove me
  71 #if 1
  72 static UInt sMaxDBDMASegment;
  73 if (!sMaxDBDMASegment) {
  74     sMaxDBDMASegment = (UInt) -1;
  75     if (PE_parse_boot_argn("mseg", &sMaxDBDMASegment, sizeof (sMaxDBDMASegment)))
  76         IOLog("Setting MaxDBDMASegment to %d\n", sMaxDBDMASegment);
  77 }
  78
  79 if (inMaxSegmentSize > sMaxDBDMASegment) inMaxSegmentSize = sMaxDBDMASegment;
  80 #endif
  81
  82     if (!super::init())
  83         return false;
  84
  85     if (!inSegFunc)
  86         return false;
  87
  88     outSeg              = inSegFunc;
  89     maxSegmentSize      = inMaxSegmentSize;
  90     if (inMaxTransferSize)
  91         maxTransferSize = inMaxTransferSize;
  92     else
  93         maxTransferSize = (IOPhysicalLength) -1;
  94     alignMask           = inAlignment - 1;
  95     assert(alignMask == 0);             // No alignment code yet!
  96
  97     return true;
  98 }
  99
 100 /* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
 101
 102 UInt32
 103 IOMemoryCursor::genPhysicalSegments(IOMemoryDescriptor *inDescriptor,
 104                                     IOByteCount         fromPosition,
 105                                     void *              inSegments,
 106                                     UInt32              inMaxSegments,
 107                                     UInt32              inMaxTransferSize,
 108                                     IOByteCount         *outTransferSize)
 109 {
 110     if (!inDescriptor)
 111         return 0;
 112
 113     if (!inMaxSegments)
 114         return 0;
 115
 116     if (!inMaxTransferSize)
 117         inMaxTransferSize = maxTransferSize;
 118
 119     /*
 120      * Iterate over the packet, translating segments where allowed
 121      *
 122      * If we finished cleanly return number of segments found
 123      * and update the position in the descriptor.
 124      */
 125     PhysicalSegment curSeg = { 0, 0 };
 126     UInt curSegIndex = 0;
 127     UInt curTransferSize = 0;
 128     IOByteCount inDescriptorLength = inDescriptor->getLength();
 129     PhysicalSegment seg = { 0, 0 };
 130
 131     while ((seg.location) || (fromPosition < inDescriptorLength))
 132     {
 133         if (!seg.location)
 134         {
 135             seg.location = inDescriptor->getPhysicalSegment(
 136                                fromPosition, (IOByteCount*)&seg.length);
 137             assert(seg.location);
 138             assert(seg.length);
 139             fromPosition += seg.length;
 140         }
 141
 142         if (!curSeg.location)
 143         {
 144             curTransferSize += seg.length;
 145             curSeg = seg;
 146             seg.location = 0;
 147         }
 148         else if ((curSeg.location + curSeg.length == seg.location))
 149         {
 150             curTransferSize += seg.length;
 151             curSeg.length += seg.length;
 152             seg.location = 0;
 153         }
 154
 155         if (!seg.location)
 156         {
 157             if ((curSeg.length > maxSegmentSize))
 158             {
 159                 seg.location = curSeg.location + maxSegmentSize;
 160                 seg.length = curSeg.length - maxSegmentSize;
 161                 curTransferSize -= seg.length;
 162                 curSeg.length -= seg.length;
 163             }
 164
 165             if ((curTransferSize >= inMaxTransferSize))
 166             {
 167                 curSeg.length -= curTransferSize - inMaxTransferSize;
 168                 curTransferSize = inMaxTransferSize;
 169                 break;
 170             }
 171         }
 172
 173         if (seg.location)
 174         {
 175             if ((curSegIndex + 1 == inMaxSegments))
 176                 break;
 177             (*outSeg)(curSeg, inSegments, curSegIndex++);
 178             curSeg.location = 0;
 179         }
 180     }
 181
 182     if (curSeg.location)
 183         (*outSeg)(curSeg, inSegments, curSegIndex++);
 184
 185     if (outTransferSize)
 186         *outTransferSize = curTransferSize;
 187
 188     return curSegIndex;
 189 }
 190
 191 /************************ class IONaturalMemoryCursor ************************/
 192
 193 #undef super
 194 #define super IOMemoryCursor
 195 OSDefineMetaClassAndStructors(IONaturalMemoryCursor, IOMemoryCursor)
 196
 197 void IONaturalMemoryCursor::outputSegment(PhysicalSegment segment,
 198                                           void *          outSegments,
 199                                           UInt32          outSegmentIndex)
 200 {
 201     ((PhysicalSegment *) outSegments)[outSegmentIndex] = segment;
 202 }
 203
 204 IONaturalMemoryCursor *
 205 IONaturalMemoryCursor::withSpecification(IOPhysicalLength inMaxSegmentSize,
 206                                          IOPhysicalLength inMaxTransferSize,
 207                                          IOPhysicalLength inAlignment)
 208 {
 209     IONaturalMemoryCursor *me = new IONaturalMemoryCursor;
 210
 211     if (me && !me->initWithSpecification(inMaxSegmentSize,
 212                                          inMaxTransferSize,
 213                                          inAlignment))
 214     {
 215         me->release();
 216         return 0;
 217     }
 218
 219     return me;
 220 }
 221
 222 bool
 223 IONaturalMemoryCursor::initWithSpecification(IOPhysicalLength inMaxSegmentSize,
 224                                              IOPhysicalLength inMaxTransferSize,
 225                                              IOPhysicalLength inAlignment)
 226 {
 227     return super::initWithSpecification(&IONaturalMemoryCursor::outputSegment,
 228                                         inMaxSegmentSize,
 229                                         inMaxTransferSize,
 230                                         inAlignment);
 231 }
 232
 233 /************************** class IOBigMemoryCursor **************************/
 234
 235 #undef super
 236 #define super IOMemoryCursor
 237 OSDefineMetaClassAndStructors(IOBigMemoryCursor, IOMemoryCursor)
 238
 239 void
 240 IOBigMemoryCursor::outputSegment(PhysicalSegment inSegment,
 241                                  void *          inSegments,
 242                                  UInt32          inSegmentIndex)
 243 {
 244     IOPhysicalAddress * segment;
 245
 246     segment = &((PhysicalSegment *) inSegments)[inSegmentIndex].location;
 247     OSWriteBigInt(segment, 0, inSegment.location);
 248     OSWriteBigInt(segment, sizeof(IOPhysicalAddress), inSegment.length);
 249 }
 250
 251 IOBigMemoryCursor *
 252 IOBigMemoryCursor::withSpecification(IOPhysicalLength inMaxSegmentSize,
 253                                      IOPhysicalLength inMaxTransferSize,
 254                                      IOPhysicalLength inAlignment)
 255 {
 256     IOBigMemoryCursor * me = new IOBigMemoryCursor;
 257
 258     if (me && !me->initWithSpecification(inMaxSegmentSize,
 259                                          inMaxTransferSize,
 260                                          inAlignment))
 261     {
 262         me->release();
 263         return 0;
 264     }
 265
 266     return me;
 267 }
 268
 269 bool
 270 IOBigMemoryCursor::initWithSpecification(IOPhysicalLength inMaxSegmentSize,
 271                                          IOPhysicalLength inMaxTransferSize,
 272                                          IOPhysicalLength inAlignment)
 273 {
 274     return super::initWithSpecification(&IOBigMemoryCursor::outputSegment,
 275                                         inMaxSegmentSize,
 276                                         inMaxTransferSize,
 277                                         inAlignment);
 278 }
 279
 280 /************************* class IOLittleMemoryCursor ************************/
 281
 282 #undef super
 283 #define super IOMemoryCursor
 284 OSDefineMetaClassAndStructors(IOLittleMemoryCursor, IOMemoryCursor)
 285
 286 void
 287 IOLittleMemoryCursor::outputSegment(PhysicalSegment inSegment,
 288                                     void *          inSegments,
 289                                     UInt32          inSegmentIndex)
 290 {
 291     IOPhysicalAddress * segment;
 292
 293     segment = &((PhysicalSegment *) inSegments)[inSegmentIndex].location;
 294     OSWriteLittleInt(segment, 0, inSegment.location);
 295     OSWriteLittleInt(segment, sizeof(IOPhysicalAddress), inSegment.length);
 296 }
 297
 298 IOLittleMemoryCursor *
 299 IOLittleMemoryCursor::withSpecification(IOPhysicalLength inMaxSegmentSize,
 300                                         IOPhysicalLength inMaxTransferSize,
 301                                         IOPhysicalLength inAlignment)
 302 {
 303     IOLittleMemoryCursor * me = new IOLittleMemoryCursor;
 304
 305     if (me && !me->initWithSpecification(inMaxSegmentSize,
 306                                          inMaxTransferSize,
 307                                          inAlignment))
 308     {
 309         me->release();
 310         return 0;
 311     }
 312
 313     return me;
 314 }
 315
 316 /* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
 317
 318 bool
 319 IOLittleMemoryCursor::initWithSpecification(IOPhysicalLength inMaxSegmentSize,
 320                                             IOPhysicalLength inMaxTransferSize,
 321                                             IOPhysicalLength inAlignment)
 322 {
 323     return super::initWithSpecification(&IOLittleMemoryCursor::outputSegment,
 324                                         inMaxSegmentSize,
 325                                         inMaxTransferSize,
 326                                         inAlignment);
 327 }