iokit/IOKit/IOBufferMemoryDescriptor.h

   1 /*
   2  * Copyright (c) 1998-2000 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * Copyright (c) 1999-2003 Apple Computer, Inc.  All Rights Reserved.
   7  *
   8  * This file contains Original Code and/or Modifications of Original Code
   9  * as defined in and that are subject to the Apple Public Source License
  10  * Version 2.0 (the 'License'). You may not use this file except in
  11  * compliance with the License. Please obtain a copy of the License at
  12  * http://www.opensource.apple.com/apsl/ and read it before using this
  13  * file.
  14  *
  15  * The Original Code and all software distributed under the License are
  16  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  17  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  18  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  19  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  20  * Please see the License for the specific language governing rights and
  21  * limitations under the License.
  22  *
  23  * @APPLE_LICENSE_HEADER_END@
  24  */
  25 #ifndef _IOBUFFERMEMORYDESCRIPTOR_H
  26 #define _IOBUFFERMEMORYDESCRIPTOR_H
  27
  28 #include <IOKit/IOMemoryDescriptor.h>
  29
  30 enum {
  31     kIOMemoryPhysicallyContiguous       = 0x00000010,
  32     kIOMemoryPageable                   = 0x00000020,
  33     kIOMemorySharingTypeMask            = 0x000f0000,
  34     kIOMemoryUnshared                   = 0x00000000,
  35     kIOMemoryKernelUserShared           = 0x00010000,
  36 };
  37
  38 #define _IOBUFFERMEMORYDESCRIPTOR_INTASKWITHOPTIONS_    1
  39
  40 class IOBufferMemoryDescriptor : public IOGeneralMemoryDescriptor
  41 {
  42     OSDeclareDefaultStructors(IOBufferMemoryDescriptor);
  43
  44 protected:
  45 /*! @struct ExpansionData
  46     @discussion This structure will be used to expand the capablilties of this class in the future.
  47     */
  48     struct ExpansionData {
  49         vm_map_t        map;
  50     };
  51
  52 /*! @var reserved
  53     Reserved for future use.  (Internal use only)  */
  54     ExpansionData * reserved;
  55
  56 protected:
  57     void *               _buffer;
  58     vm_size_t            _capacity;
  59     vm_offset_t          _alignment;
  60     IOOptionBits         _options;
  61     IOPhysicalAddress *  _physAddrs;
  62     unsigned             _physSegCount;
  63
  64 private:
  65     virtual bool initWithOptions(
  66                                IOOptionBits options,
  67                                vm_size_t    capacity,
  68                                vm_offset_t  alignment,
  69                                task_t       inTask);
  70
  71     OSMetaClassDeclareReservedUsed(IOBufferMemoryDescriptor, 0);
  72     OSMetaClassDeclareReservedUnused(IOBufferMemoryDescriptor, 1);
  73     OSMetaClassDeclareReservedUnused(IOBufferMemoryDescriptor, 2);
  74     OSMetaClassDeclareReservedUnused(IOBufferMemoryDescriptor, 3);
  75     OSMetaClassDeclareReservedUnused(IOBufferMemoryDescriptor, 4);
  76     OSMetaClassDeclareReservedUnused(IOBufferMemoryDescriptor, 5);
  77     OSMetaClassDeclareReservedUnused(IOBufferMemoryDescriptor, 6);
  78     OSMetaClassDeclareReservedUnused(IOBufferMemoryDescriptor, 7);
  79     OSMetaClassDeclareReservedUnused(IOBufferMemoryDescriptor, 8);
  80     OSMetaClassDeclareReservedUnused(IOBufferMemoryDescriptor, 9);
  81     OSMetaClassDeclareReservedUnused(IOBufferMemoryDescriptor, 10);
  82     OSMetaClassDeclareReservedUnused(IOBufferMemoryDescriptor, 11);
  83     OSMetaClassDeclareReservedUnused(IOBufferMemoryDescriptor, 12);
  84     OSMetaClassDeclareReservedUnused(IOBufferMemoryDescriptor, 13);
  85     OSMetaClassDeclareReservedUnused(IOBufferMemoryDescriptor, 14);
  86     OSMetaClassDeclareReservedUnused(IOBufferMemoryDescriptor, 15);
  87
  88 protected:
  89     virtual void free();
  90
  91     virtual bool initWithAddress( void *      address,       /* not supported */
  92                                   IOByteCount withLength,
  93                                   IODirection withDirection );
  94
  95     virtual bool initWithAddress( vm_address_t address,      /* not supported */
  96                                   IOByteCount  withLength,
  97                                   IODirection  withDirection,
  98                                   task_t       withTask );
  99
 100     virtual bool initWithPhysicalAddress(
 101                                   IOPhysicalAddress address, /* not supported */
 102                                   IOByteCount       withLength,
 103                                   IODirection       withDirection );
 104
 105     virtual bool initWithPhysicalRanges(
 106                                   IOPhysicalRange * ranges,  /* not supported */
 107                                   UInt32            withCount,
 108                                   IODirection       withDirection,
 109                                   bool              asReference = false );
 110
 111     virtual bool initWithRanges(  IOVirtualRange * ranges,   /* not supported */
 112                                   UInt32           withCount,
 113                                   IODirection      withDirection,
 114                                   task_t           withTask,
 115                                   bool             asReference = false );
 116
 117     IOGeneralMemoryDescriptor::withAddress;                  /* not supported */
 118     IOGeneralMemoryDescriptor::withPhysicalAddress;          /* not supported */
 119     IOGeneralMemoryDescriptor::withPhysicalRanges;           /* not supported */
 120     IOGeneralMemoryDescriptor::withRanges;                   /* not supported */
 121     IOGeneralMemoryDescriptor::withSubRange;                 /* not supported */
 122
 123 public:
 124
 125     /*
 126      * withOptions:
 127      *
 128      * Returns a new IOBufferMemoryDescriptor with a buffer large enough to
 129      * hold capacity bytes.  The descriptor's length is initially set to the
 130      * capacity.
 131      */
 132     virtual bool initWithOptions(   IOOptionBits options,
 133                                     vm_size_t    capacity,
 134                                     vm_offset_t  alignment);
 135
 136     static IOBufferMemoryDescriptor * withOptions(  IOOptionBits options,
 137                                                     vm_size_t    capacity,
 138                                                     vm_offset_t  alignment = 1);
 139
 140 /*! @function inTaskWithOptions
 141     @abstract Create a memory buffer with memory descriptor for that buffer. Added in Mac OS X 10.2.
 142     @discussion This method allocates a memory buffer with a given size and alignment in the task's address space specified, and returns a memory descriptor instance representing the memory. It is recommended memory allocated for I/O or sharing via mapping be created via IOBufferMemoryDescriptor. Options passed with the request specify the kind of memory to be allocated - pageablity and sharing are specified with option bits. This function may block and so should not be called from interrupt level or while a simple lock is held.
 143     @param inTask The task the buffer will be allocated in.
 144     @param options Options for the allocation:
 145     kIOMemoryPhysicallyContiguous - pass to request memory be physically contiguous. This option is heavily discouraged. The request may fail if memory is fragmented, may cause large amounts of paging activity, and may take a very long time to execute.
 146     kIOMemoryPageable - pass to request memory be non-wired - the default for kernel allocated memory is wired.
 147     kIOMemoryKernelUserShared - pass to request memory that will be mapped into both the kernel and client applications.
 148     @param capacity The number of bytes to allocate.
 149     @param alignment The minimum required alignment of the buffer in bytes - 1 is the default for no required alignment. For example, pass 256 to get memory allocated at an address with bits 0-7 zero.
 150     @result An instance of class IOBufferMemoryDescriptor. To be released by the caller, which will free the memory desriptor and associated buffer. */
 151
 152     static IOBufferMemoryDescriptor * inTaskWithOptions(
 153                                             task_t       inTask,
 154                                             IOOptionBits options,
 155                                             vm_size_t    capacity,
 156                                             vm_offset_t  alignment = 1);
 157
 158     /*
 159      * withCapacity:
 160      *
 161      * Returns a new IOBufferMemoryDescriptor with a buffer large enough to
 162      * hold capacity bytes.  The descriptor's length is initially set to the
 163      * capacity.
 164      */
 165     static IOBufferMemoryDescriptor * withCapacity(
 166                                      vm_size_t    capacity,
 167                                      IODirection  withDirection,
 168                                      bool         withContiguousMemory = false);
 169     /*
 170      * initWithBytes:
 171      *
 172      * Initialize a new IOBufferMemoryDescriptor preloaded with bytes (copied).
 173      * The descriptor's length and capacity are set to the input buffer's size.
 174      */
 175     virtual bool initWithBytes(const void * bytes,
 176                                vm_size_t    withLength,
 177                                IODirection  withDirection,
 178                                bool         withContiguousMemory = false);
 179
 180     /*
 181      * withBytes:
 182      *
 183      * Returns a new IOBufferMemoryDescriptor preloaded with bytes (copied).
 184      * The descriptor's length and capacity are set to the input buffer's size.
 185      */
 186     static IOBufferMemoryDescriptor * withBytes(
 187                                      const void * bytes,
 188                                      vm_size_t    withLength,
 189                                      IODirection  withDirection,
 190                                      bool         withContiguousMemory = false);
 191
 192     /*
 193      * setLength:
 194      *
 195      * Change the buffer length of the memory descriptor.  When a new buffer
 196      * is created, the initial length of the buffer is set to be the same as
 197      * the capacity.  The length can be adjusted via setLength for a shorter
 198      * transfer (there is no need to create more buffer descriptors when you
 199      * can reuse an existing one, even for different transfer sizes).   Note
 200      * that the specified length must not exceed the capacity of the buffer.
 201      */
 202     virtual void setLength(vm_size_t length);
 203
 204     /*
 205      * setDirection:
 206      *
 207      * Change the direction of the transfer.  This method allows one to redirect
 208      * the descriptor's transfer direction.  This eliminates the need to destroy
 209      * and create new buffers when different transfer directions are needed.
 210      */
 211     virtual void setDirection(IODirection direction);
 212
 213     /*
 214      * getCapacity:
 215      *
 216      * Get the buffer capacity
 217      */
 218     virtual vm_size_t getCapacity() const;
 219
 220     /*
 221      * getBytesNoCopy:
 222      *
 223      * Return the virtual address of the beginning of the buffer
 224      */
 225     virtual void *getBytesNoCopy();
 226
 227     /*
 228      * getBytesNoCopy:
 229      *
 230      * Return the virtual address of an offset from the beginning of the buffer
 231      */
 232     virtual void *getBytesNoCopy(vm_size_t start, vm_size_t withLength);
 233
 234     /*
 235      * appendBytes:
 236      *
 237      * Add some data to the end of the buffer.  This method automatically
 238      * maintains the memory descriptor buffer length.  Note that appendBytes
 239      * will not copy past the end of the memory descriptor's current capacity.
 240      */
 241     virtual bool appendBytes(const void *bytes, vm_size_t withLength);
 242 };
 243
 244 #endif /* !_IOBUFFERMEMORYDESCRIPTOR_H */