iokit/IOKit/IOBufferMemoryDescriptor.h

   1 /*
   2  * Copyright (c) 1998-2000 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_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. Please obtain a copy of the License at
  10  * http://www.opensource.apple.com/apsl/ and read it before using this
  11  * file.
  12  *
  13  * The Original Code and all software distributed under the License are
  14  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  15  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  16  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  17  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  18  * Please see the License for the specific language governing rights and
  19  * limitations under the License.
  20  *
  21  * @APPLE_LICENSE_HEADER_END@
  22  */
  23 #ifndef _IOBUFFERMEMORYDESCRIPTOR_H
  24 #define _IOBUFFERMEMORYDESCRIPTOR_H
  25
  26 #include <IOKit/IOMemoryDescriptor.h>
  27
  28 enum {
  29     kIOMemoryPhysicallyContiguous       = 0x00000010,
  30     kIOMemoryPageable                   = 0x00000020,
  31     kIOMemoryPurgeable                  = 0x00000040,
  32     kIOMemorySharingTypeMask            = 0x000f0000,
  33     kIOMemoryUnshared                   = 0x00000000,
  34     kIOMemoryKernelUserShared           = 0x00010000
  35 };
  36
  37 #define _IOBUFFERMEMORYDESCRIPTOR_INTASKWITHOPTIONS_    1
  38 /*!
  39     @class IOBufferMemoryDescriptor
  40     @abstract Provides a simple memory descriptor that allocates its own buffer memory.
  41 */
  42
  43 class IOBufferMemoryDescriptor : public IOGeneralMemoryDescriptor
  44 {
  45     OSDeclareDefaultStructors(IOBufferMemoryDescriptor);
  46
  47 protected:
  48 /*! @struct ExpansionData
  49     @discussion This structure will be used to expand the capablilties of this class in the future.
  50     */
  51     struct ExpansionData {
  52         vm_map_t        map;
  53     };
  54
  55 /*! @var reserved
  56     Reserved for future use.  (Internal use only)  */
  57     ExpansionData * reserved;
  58
  59 protected:
  60     void *               _buffer;
  61     vm_size_t            _capacity;
  62     vm_offset_t          _alignment;
  63     IOOptionBits         _options;
  64     IOPhysicalAddress *  _physAddrs;
  65     unsigned             _physSegCount;
  66
  67 private:
  68     virtual bool initWithOptions(
  69                                IOOptionBits options,
  70                                vm_size_t    capacity,
  71                                vm_offset_t  alignment,
  72                                task_t       inTask);
  73
  74     OSMetaClassDeclareReservedUsed(IOBufferMemoryDescriptor, 0);
  75     OSMetaClassDeclareReservedUnused(IOBufferMemoryDescriptor, 1);
  76     OSMetaClassDeclareReservedUnused(IOBufferMemoryDescriptor, 2);
  77     OSMetaClassDeclareReservedUnused(IOBufferMemoryDescriptor, 3);
  78     OSMetaClassDeclareReservedUnused(IOBufferMemoryDescriptor, 4);
  79     OSMetaClassDeclareReservedUnused(IOBufferMemoryDescriptor, 5);
  80     OSMetaClassDeclareReservedUnused(IOBufferMemoryDescriptor, 6);
  81     OSMetaClassDeclareReservedUnused(IOBufferMemoryDescriptor, 7);
  82     OSMetaClassDeclareReservedUnused(IOBufferMemoryDescriptor, 8);
  83     OSMetaClassDeclareReservedUnused(IOBufferMemoryDescriptor, 9);
  84     OSMetaClassDeclareReservedUnused(IOBufferMemoryDescriptor, 10);
  85     OSMetaClassDeclareReservedUnused(IOBufferMemoryDescriptor, 11);
  86     OSMetaClassDeclareReservedUnused(IOBufferMemoryDescriptor, 12);
  87     OSMetaClassDeclareReservedUnused(IOBufferMemoryDescriptor, 13);
  88     OSMetaClassDeclareReservedUnused(IOBufferMemoryDescriptor, 14);
  89     OSMetaClassDeclareReservedUnused(IOBufferMemoryDescriptor, 15);
  90
  91 protected:
  92     virtual void free();
  93
  94     virtual bool initWithAddress( void *      address,       /* not supported */
  95                                   IOByteCount withLength,
  96                                   IODirection withDirection );
  97
  98     virtual bool initWithAddress( vm_address_t address,      /* not supported */
  99                                   IOByteCount  withLength,
 100                                   IODirection  withDirection,
 101                                   task_t       withTask );
 102
 103     virtual bool initWithPhysicalAddress(
 104                                   IOPhysicalAddress address, /* not supported */
 105                                   IOByteCount       withLength,
 106                                   IODirection       withDirection );
 107
 108     virtual bool initWithPhysicalRanges(
 109                                   IOPhysicalRange * ranges,  /* not supported */
 110                                   UInt32            withCount,
 111                                   IODirection       withDirection,
 112                                   bool              asReference = false );
 113
 114     virtual bool initWithRanges(  IOVirtualRange * ranges,   /* not supported */
 115                                   UInt32           withCount,
 116                                   IODirection      withDirection,
 117                                   task_t           withTask,
 118                                   bool             asReference = false );
 119
 120     IOGeneralMemoryDescriptor::withAddress;                  /* not supported */
 121     IOGeneralMemoryDescriptor::withPhysicalAddress;          /* not supported */
 122     IOGeneralMemoryDescriptor::withPhysicalRanges;           /* not supported */
 123     IOGeneralMemoryDescriptor::withRanges;                   /* not supported */
 124     IOGeneralMemoryDescriptor::withSubRange;                 /* not supported */
 125
 126 public:
 127
 128     /*
 129      * withOptions:
 130      *
 131      * Returns a new IOBufferMemoryDescriptor with a buffer large enough to
 132      * hold capacity bytes.  The descriptor's length is initially set to the
 133      * capacity.
 134      */
 135     virtual bool initWithOptions(   IOOptionBits options,
 136                                     vm_size_t    capacity,
 137                                     vm_offset_t  alignment);
 138
 139     static IOBufferMemoryDescriptor * withOptions(  IOOptionBits options,
 140                                                     vm_size_t    capacity,
 141                                                     vm_offset_t  alignment = 1);
 142
 143 /*! @function inTaskWithOptions
 144     @abstract Creates a memory buffer with memory descriptor for that buffer.
 145     @discussion Added in Mac OS X 10.2, 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 that 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.
 146     @param inTask The task the buffer will be allocated in.
 147     @param options Options for the allocation:<br>
 148     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.<br>
 149     kIOMemoryPageable - pass to request memory be non-wired - the default for kernel allocated memory is wired.<br>
 150     kIOMemoryPurgeable - pass to request memory that may later have its purgeable state set with IOMemoryDescriptor::setPurgeable. Only supported for kIOMemoryPageable allocations.<br>
 151     kIOMemoryKernelUserShared - pass to request memory that will be mapped into both the kernel and client applications.
 152     @param capacity The number of bytes to allocate.
 153     @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.
 154     @result Returns an instance of class IOBufferMemoryDescriptor to be released by the caller, which will free the memory desriptor and associated buffer. */
 155
 156     static IOBufferMemoryDescriptor * inTaskWithOptions(
 157                                             task_t       inTask,
 158                                             IOOptionBits options,
 159                                             vm_size_t    capacity,
 160                                             vm_offset_t  alignment = 1);
 161
 162     /*
 163      * withCapacity:
 164      *
 165      * Returns a new IOBufferMemoryDescriptor with a buffer large enough to
 166      * hold capacity bytes.  The descriptor's length is initially set to the
 167      * capacity.
 168      */
 169     static IOBufferMemoryDescriptor * withCapacity(
 170                                      vm_size_t    capacity,
 171                                      IODirection  withDirection,
 172                                      bool         withContiguousMemory = false);
 173     /*
 174      * initWithBytes:
 175      *
 176      * Initialize a new IOBufferMemoryDescriptor preloaded with bytes (copied).
 177      * The descriptor's length and capacity are set to the input buffer's size.
 178      */
 179     virtual bool initWithBytes(const void * bytes,
 180                                vm_size_t    withLength,
 181                                IODirection  withDirection,
 182                                bool         withContiguousMemory = false);
 183
 184     /*
 185      * withBytes:
 186      *
 187      * Returns a new IOBufferMemoryDescriptor preloaded with bytes (copied).
 188      * The descriptor's length and capacity are set to the input buffer's size.
 189      */
 190     static IOBufferMemoryDescriptor * withBytes(
 191                                      const void * bytes,
 192                                      vm_size_t    withLength,
 193                                      IODirection  withDirection,
 194                                      bool         withContiguousMemory = false);
 195
 196     /*
 197      * setLength:
 198      *
 199      * Change the buffer length of the memory descriptor.  When a new buffer
 200      * is created, the initial length of the buffer is set to be the same as
 201      * the capacity.  The length can be adjusted via setLength for a shorter
 202      * transfer (there is no need to create more buffer descriptors when you
 203      * can reuse an existing one, even for different transfer sizes).   Note
 204      * that the specified length must not exceed the capacity of the buffer.
 205      */
 206     virtual void setLength(vm_size_t length);
 207
 208     /*
 209      * setDirection:
 210      *
 211      * Change the direction of the transfer.  This method allows one to redirect
 212      * the descriptor's transfer direction.  This eliminates the need to destroy
 213      * and create new buffers when different transfer directions are needed.
 214      */
 215     virtual void setDirection(IODirection direction);
 216
 217     /*
 218      * getCapacity:
 219      *
 220      * Get the buffer capacity
 221      */
 222     virtual vm_size_t getCapacity() const;
 223
 224     /*
 225      * getBytesNoCopy:
 226      *
 227      * Return the virtual address of the beginning of the buffer
 228      */
 229     virtual void *getBytesNoCopy();
 230
 231     /*
 232      * getBytesNoCopy:
 233      *
 234      * Return the virtual address of an offset from the beginning of the buffer
 235      */
 236     virtual void *getBytesNoCopy(vm_size_t start, vm_size_t withLength);
 237
 238     /*
 239      * appendBytes:
 240      *
 241      * Add some data to the end of the buffer.  This method automatically
 242      * maintains the memory descriptor buffer length.  Note that appendBytes
 243      * will not copy past the end of the memory descriptor's current capacity.
 244      */
 245     virtual bool appendBytes(const void *bytes, vm_size_t withLength);
 246 };
 247
 248 #endif /* !_IOBUFFERMEMORYDESCRIPTOR_H */