iokit/IOKit/IOBufferMemoryDescriptor.h

   1 /*
   2  * Copyright (c) 1998-2000 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * The contents of this file constitute Original Code as defined in and
   7  * are subject to the Apple Public Source License Version 1.1 (the
   8  * "License").  You may not use this file except in compliance with the
   9  * License.  Please obtain a copy of the License at
  10  * http://www.apple.com/publicsource and read it before using this file.
  11  *
  12  * This Original Code and all software distributed under the License are
  13  * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  14  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  15  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  16  * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT.  Please see the
  17  * License for the specific language governing rights and limitations
  18  * under the License.
  19  *
  20  * @APPLE_LICENSE_HEADER_END@
  21  */
  22 #ifndef _IOBUFFERMEMORYDESCRIPTOR_H
  23 #define _IOBUFFERMEMORYDESCRIPTOR_H
  24
  25 #include <IOKit/IOMemoryDescriptor.h>
  26
  27 enum {
  28     kIOMemoryPhysicallyContiguous       = 0x00000010,
  29     kIOMemoryPageable                   = 0x00000020,
  30     kIOMemoryPurgeable                  = 0x00000040,
  31     kIOMemorySharingTypeMask            = 0x000f0000,
  32     kIOMemoryUnshared                   = 0x00000000,
  33     kIOMemoryKernelUserShared           = 0x00010000
  34 };
  35
  36 #define _IOBUFFERMEMORYDESCRIPTOR_INTASKWITHOPTIONS_    1
  37 /*!
  38     @class IOBufferMemoryDescriptor
  39     @abstract Provides a simple memory descriptor that allocates its own buffer memory.
  40 */
  41
  42 class IOBufferMemoryDescriptor : public IOGeneralMemoryDescriptor
  43 {
  44     OSDeclareDefaultStructors(IOBufferMemoryDescriptor);
  45
  46 protected:
  47 /*! @struct ExpansionData
  48     @discussion This structure will be used to expand the capablilties of this class in the future.
  49     */
  50     struct ExpansionData {
  51         vm_map_t        map;
  52     };
  53
  54 /*! @var reserved
  55     Reserved for future use.  (Internal use only)  */
  56     ExpansionData * reserved;
  57
  58 protected:
  59     void *               _buffer;
  60     vm_size_t            _capacity;
  61     vm_offset_t          _alignment;
  62     IOOptionBits         _options;
  63     IOPhysicalAddress *  _physAddrs;
  64     unsigned             _physSegCount;
  65
  66 private:
  67     virtual bool initWithOptions(
  68                                IOOptionBits options,
  69                                vm_size_t    capacity,
  70                                vm_offset_t  alignment,
  71                                task_t       inTask);
  72
  73     OSMetaClassDeclareReservedUsed(IOBufferMemoryDescriptor, 0);
  74     OSMetaClassDeclareReservedUnused(IOBufferMemoryDescriptor, 1);
  75     OSMetaClassDeclareReservedUnused(IOBufferMemoryDescriptor, 2);
  76     OSMetaClassDeclareReservedUnused(IOBufferMemoryDescriptor, 3);
  77     OSMetaClassDeclareReservedUnused(IOBufferMemoryDescriptor, 4);
  78     OSMetaClassDeclareReservedUnused(IOBufferMemoryDescriptor, 5);
  79     OSMetaClassDeclareReservedUnused(IOBufferMemoryDescriptor, 6);
  80     OSMetaClassDeclareReservedUnused(IOBufferMemoryDescriptor, 7);
  81     OSMetaClassDeclareReservedUnused(IOBufferMemoryDescriptor, 8);
  82     OSMetaClassDeclareReservedUnused(IOBufferMemoryDescriptor, 9);
  83     OSMetaClassDeclareReservedUnused(IOBufferMemoryDescriptor, 10);
  84     OSMetaClassDeclareReservedUnused(IOBufferMemoryDescriptor, 11);
  85     OSMetaClassDeclareReservedUnused(IOBufferMemoryDescriptor, 12);
  86     OSMetaClassDeclareReservedUnused(IOBufferMemoryDescriptor, 13);
  87     OSMetaClassDeclareReservedUnused(IOBufferMemoryDescriptor, 14);
  88     OSMetaClassDeclareReservedUnused(IOBufferMemoryDescriptor, 15);
  89
  90 protected:
  91     virtual void free();
  92
  93     virtual bool initWithAddress( void *      address,       /* not supported */
  94                                   IOByteCount withLength,
  95                                   IODirection withDirection );
  96
  97     virtual bool initWithAddress( vm_address_t address,      /* not supported */
  98                                   IOByteCount  withLength,
  99                                   IODirection  withDirection,
 100                                   task_t       withTask );
 101
 102     virtual bool initWithPhysicalAddress(
 103                                   IOPhysicalAddress address, /* not supported */
 104                                   IOByteCount       withLength,
 105                                   IODirection       withDirection );
 106
 107     virtual bool initWithPhysicalRanges(
 108                                   IOPhysicalRange * ranges,  /* not supported */
 109                                   UInt32            withCount,
 110                                   IODirection       withDirection,
 111                                   bool              asReference = false );
 112
 113     virtual bool initWithRanges(  IOVirtualRange * ranges,   /* not supported */
 114                                   UInt32           withCount,
 115                                   IODirection      withDirection,
 116                                   task_t           withTask,
 117                                   bool             asReference = false );
 118
 119     IOGeneralMemoryDescriptor::withAddress;                  /* not supported */
 120     IOGeneralMemoryDescriptor::withPhysicalAddress;          /* not supported */
 121     IOGeneralMemoryDescriptor::withPhysicalRanges;           /* not supported */
 122     IOGeneralMemoryDescriptor::withRanges;                   /* not supported */
 123     IOGeneralMemoryDescriptor::withSubRange;                 /* not supported */
 124
 125 public:
 126
 127     /*
 128      * withOptions:
 129      *
 130      * Returns a new IOBufferMemoryDescriptor with a buffer large enough to
 131      * hold capacity bytes.  The descriptor's length is initially set to the
 132      * capacity.
 133      */
 134     virtual bool initWithOptions(   IOOptionBits options,
 135                                     vm_size_t    capacity,
 136                                     vm_offset_t  alignment);
 137
 138     static IOBufferMemoryDescriptor * withOptions(  IOOptionBits options,
 139                                                     vm_size_t    capacity,
 140                                                     vm_offset_t  alignment = 1);
 141
 142 /*! @function inTaskWithOptions
 143     @abstract Creates a memory buffer with memory descriptor for that buffer.
 144     @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.
 145     @param inTask The task the buffer will be allocated in.
 146     @param options Options for the allocation:<br>
 147     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>
 148     kIOMemoryPageable - pass to request memory be non-wired - the default for kernel allocated memory is wired.<br>
 149     kIOMemoryPurgeable - pass to request memory that may later have its purgeable state set with IOMemoryDescriptor::setPurgeable. Only supported for kIOMemoryPageable allocations.<br>
 150     kIOMemoryKernelUserShared - pass to request memory that will be mapped into both the kernel and client applications.
 151     @param capacity The number of bytes to allocate.
 152     @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.
 153     @result Returns an instance of class IOBufferMemoryDescriptor to be released by the caller, which will free the memory desriptor and associated buffer. */
 154
 155     static IOBufferMemoryDescriptor * inTaskWithOptions(
 156                                             task_t       inTask,
 157                                             IOOptionBits options,
 158                                             vm_size_t    capacity,
 159                                             vm_offset_t  alignment = 1);
 160
 161     /*
 162      * withCapacity:
 163      *
 164      * Returns a new IOBufferMemoryDescriptor with a buffer large enough to
 165      * hold capacity bytes.  The descriptor's length is initially set to the
 166      * capacity.
 167      */
 168     static IOBufferMemoryDescriptor * withCapacity(
 169                                      vm_size_t    capacity,
 170                                      IODirection  withDirection,
 171                                      bool         withContiguousMemory = false);
 172     /*
 173      * initWithBytes:
 174      *
 175      * Initialize a new IOBufferMemoryDescriptor preloaded with bytes (copied).
 176      * The descriptor's length and capacity are set to the input buffer's size.
 177      */
 178     virtual bool initWithBytes(const void * bytes,
 179                                vm_size_t    withLength,
 180                                IODirection  withDirection,
 181                                bool         withContiguousMemory = false);
 182
 183     /*
 184      * withBytes:
 185      *
 186      * Returns a new IOBufferMemoryDescriptor preloaded with bytes (copied).
 187      * The descriptor's length and capacity are set to the input buffer's size.
 188      */
 189     static IOBufferMemoryDescriptor * withBytes(
 190                                      const void * bytes,
 191                                      vm_size_t    withLength,
 192                                      IODirection  withDirection,
 193                                      bool         withContiguousMemory = false);
 194
 195     /*
 196      * setLength:
 197      *
 198      * Change the buffer length of the memory descriptor.  When a new buffer
 199      * is created, the initial length of the buffer is set to be the same as
 200      * the capacity.  The length can be adjusted via setLength for a shorter
 201      * transfer (there is no need to create more buffer descriptors when you
 202      * can reuse an existing one, even for different transfer sizes).   Note
 203      * that the specified length must not exceed the capacity of the buffer.
 204      */
 205     virtual void setLength(vm_size_t length);
 206
 207     /*
 208      * setDirection:
 209      *
 210      * Change the direction of the transfer.  This method allows one to redirect
 211      * the descriptor's transfer direction.  This eliminates the need to destroy
 212      * and create new buffers when different transfer directions are needed.
 213      */
 214     virtual void setDirection(IODirection direction);
 215
 216     /*
 217      * getCapacity:
 218      *
 219      * Get the buffer capacity
 220      */
 221     virtual vm_size_t getCapacity() const;
 222
 223     /*
 224      * getBytesNoCopy:
 225      *
 226      * Return the virtual address of the beginning of the buffer
 227      */
 228     virtual void *getBytesNoCopy();
 229
 230     /*
 231      * getBytesNoCopy:
 232      *
 233      * Return the virtual address of an offset from the beginning of the buffer
 234      */
 235     virtual void *getBytesNoCopy(vm_size_t start, vm_size_t withLength);
 236
 237     /*
 238      * appendBytes:
 239      *
 240      * Add some data to the end of the buffer.  This method automatically
 241      * maintains the memory descriptor buffer length.  Note that appendBytes
 242      * will not copy past the end of the memory descriptor's current capacity.
 243      */
 244     virtual bool appendBytes(const void *bytes, vm_size_t withLength);
 245 };
 246
 247 #endif /* !_IOBUFFERMEMORYDESCRIPTOR_H */