iokit/IOKit/IOBufferMemoryDescriptor.h

   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,
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  23  * Please see the License for the specific language governing rights and
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  26  * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
  27  */
  28 #ifndef _IOBUFFERMEMORYDESCRIPTOR_H
  29 #define _IOBUFFERMEMORYDESCRIPTOR_H
  30
  31 #include <IOKit/IOMemoryDescriptor.h>
  32
  33 enum {
  34     kIOMemoryPhysicallyContiguous       = 0x00000010,
  35     kIOMemoryPageable                   = 0x00000020,
  36     kIOMemoryPurgeable                  = 0x00000040,
  37     kIOMemorySharingTypeMask            = 0x000f0000,
  38     kIOMemoryUnshared                   = 0x00000000,
  39     kIOMemoryKernelUserShared           = 0x00010000
  40 };
  41
  42 #define _IOBUFFERMEMORYDESCRIPTOR_INTASKWITHOPTIONS_    1
  43 /*!
  44     @class IOBufferMemoryDescriptor
  45     @abstract Provides a simple memory descriptor that allocates its own buffer memory.
  46 */
  47
  48 class IOBufferMemoryDescriptor : public IOGeneralMemoryDescriptor
  49 {
  50     OSDeclareDefaultStructors(IOBufferMemoryDescriptor);
  51
  52 protected:
  53 /*! @struct ExpansionData
  54     @discussion This structure will be used to expand the capablilties of this class in the future.
  55     */
  56     struct ExpansionData {
  57         vm_map_t        map;
  58     };
  59
  60 /*! @var reserved
  61     Reserved for future use.  (Internal use only)  */
  62     ExpansionData * reserved;
  63
  64 protected:
  65     void *               _buffer;
  66     vm_size_t            _capacity;
  67     vm_offset_t          _alignment;
  68     IOOptionBits         _options;
  69     IOPhysicalAddress *  _physAddrs;
  70     unsigned             _physSegCount;
  71
  72 private:
  73     virtual bool initWithOptions(
  74                                IOOptionBits options,
  75                                vm_size_t    capacity,
  76                                vm_offset_t  alignment,
  77                                task_t       inTask);
  78
  79     OSMetaClassDeclareReservedUsed(IOBufferMemoryDescriptor, 0);
  80     OSMetaClassDeclareReservedUnused(IOBufferMemoryDescriptor, 1);
  81     OSMetaClassDeclareReservedUnused(IOBufferMemoryDescriptor, 2);
  82     OSMetaClassDeclareReservedUnused(IOBufferMemoryDescriptor, 3);
  83     OSMetaClassDeclareReservedUnused(IOBufferMemoryDescriptor, 4);
  84     OSMetaClassDeclareReservedUnused(IOBufferMemoryDescriptor, 5);
  85     OSMetaClassDeclareReservedUnused(IOBufferMemoryDescriptor, 6);
  86     OSMetaClassDeclareReservedUnused(IOBufferMemoryDescriptor, 7);
  87     OSMetaClassDeclareReservedUnused(IOBufferMemoryDescriptor, 8);
  88     OSMetaClassDeclareReservedUnused(IOBufferMemoryDescriptor, 9);
  89     OSMetaClassDeclareReservedUnused(IOBufferMemoryDescriptor, 10);
  90     OSMetaClassDeclareReservedUnused(IOBufferMemoryDescriptor, 11);
  91     OSMetaClassDeclareReservedUnused(IOBufferMemoryDescriptor, 12);
  92     OSMetaClassDeclareReservedUnused(IOBufferMemoryDescriptor, 13);
  93     OSMetaClassDeclareReservedUnused(IOBufferMemoryDescriptor, 14);
  94     OSMetaClassDeclareReservedUnused(IOBufferMemoryDescriptor, 15);
  95
  96 protected:
  97     virtual void free();
  98
  99     virtual bool initWithAddress( void *      address,       /* not supported */
 100                                   IOByteCount withLength,
 101                                   IODirection withDirection );
 102
 103     virtual bool initWithAddress( vm_address_t address,      /* not supported */
 104                                   IOByteCount  withLength,
 105                                   IODirection  withDirection,
 106                                   task_t       withTask );
 107
 108     virtual bool initWithPhysicalAddress(
 109                                   IOPhysicalAddress address, /* not supported */
 110                                   IOByteCount       withLength,
 111                                   IODirection       withDirection );
 112
 113     virtual bool initWithPhysicalRanges(
 114                                   IOPhysicalRange * ranges,  /* not supported */
 115                                   UInt32            withCount,
 116                                   IODirection       withDirection,
 117                                   bool              asReference = false );
 118
 119     virtual bool initWithRanges(  IOVirtualRange * ranges,   /* not supported */
 120                                   UInt32           withCount,
 121                                   IODirection      withDirection,
 122                                   task_t           withTask,
 123                                   bool             asReference = false );
 124
 125     IOGeneralMemoryDescriptor::withAddress;                  /* not supported */
 126     IOGeneralMemoryDescriptor::withPhysicalAddress;          /* not supported */
 127     IOGeneralMemoryDescriptor::withPhysicalRanges;           /* not supported */
 128     IOGeneralMemoryDescriptor::withRanges;                   /* not supported */
 129     IOGeneralMemoryDescriptor::withSubRange;                 /* not supported */
 130
 131 public:
 132
 133     /*
 134      * withOptions:
 135      *
 136      * Returns a new IOBufferMemoryDescriptor with a buffer large enough to
 137      * hold capacity bytes.  The descriptor's length is initially set to the
 138      * capacity.
 139      */
 140     virtual bool initWithOptions(   IOOptionBits options,
 141                                     vm_size_t    capacity,
 142                                     vm_offset_t  alignment);
 143
 144     static IOBufferMemoryDescriptor * withOptions(  IOOptionBits options,
 145                                                     vm_size_t    capacity,
 146                                                     vm_offset_t  alignment = 1);
 147
 148 /*! @function inTaskWithOptions
 149     @abstract Creates a memory buffer with memory descriptor for that buffer.
 150     @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.
 151     @param inTask The task the buffer will be allocated in.
 152     @param options Options for the allocation:<br>
 153     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>
 154     kIOMemoryPageable - pass to request memory be non-wired - the default for kernel allocated memory is wired.<br>
 155     kIOMemoryPurgeable - pass to request memory that may later have its purgeable state set with IOMemoryDescriptor::setPurgeable. Only supported for kIOMemoryPageable allocations.<br>
 156     kIOMemoryKernelUserShared - pass to request memory that will be mapped into both the kernel and client applications.
 157     @param capacity The number of bytes to allocate.
 158     @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.
 159     @result Returns an instance of class IOBufferMemoryDescriptor to be released by the caller, which will free the memory desriptor and associated buffer. */
 160
 161     static IOBufferMemoryDescriptor * inTaskWithOptions(
 162                                             task_t       inTask,
 163                                             IOOptionBits options,
 164                                             vm_size_t    capacity,
 165                                             vm_offset_t  alignment = 1);
 166
 167     /*
 168      * withCapacity:
 169      *
 170      * Returns a new IOBufferMemoryDescriptor with a buffer large enough to
 171      * hold capacity bytes.  The descriptor's length is initially set to the
 172      * capacity.
 173      */
 174     static IOBufferMemoryDescriptor * withCapacity(
 175                                      vm_size_t    capacity,
 176                                      IODirection  withDirection,
 177                                      bool         withContiguousMemory = false);
 178     /*
 179      * initWithBytes:
 180      *
 181      * Initialize a new IOBufferMemoryDescriptor preloaded with bytes (copied).
 182      * The descriptor's length and capacity are set to the input buffer's size.
 183      */
 184     virtual bool initWithBytes(const void * bytes,
 185                                vm_size_t    withLength,
 186                                IODirection  withDirection,
 187                                bool         withContiguousMemory = false);
 188
 189     /*
 190      * withBytes:
 191      *
 192      * Returns a new IOBufferMemoryDescriptor preloaded with bytes (copied).
 193      * The descriptor's length and capacity are set to the input buffer's size.
 194      */
 195     static IOBufferMemoryDescriptor * withBytes(
 196                                      const void * bytes,
 197                                      vm_size_t    withLength,
 198                                      IODirection  withDirection,
 199                                      bool         withContiguousMemory = false);
 200
 201     /*
 202      * setLength:
 203      *
 204      * Change the buffer length of the memory descriptor.  When a new buffer
 205      * is created, the initial length of the buffer is set to be the same as
 206      * the capacity.  The length can be adjusted via setLength for a shorter
 207      * transfer (there is no need to create more buffer descriptors when you
 208      * can reuse an existing one, even for different transfer sizes).   Note
 209      * that the specified length must not exceed the capacity of the buffer.
 210      */
 211     virtual void setLength(vm_size_t length);
 212
 213     /*
 214      * setDirection:
 215      *
 216      * Change the direction of the transfer.  This method allows one to redirect
 217      * the descriptor's transfer direction.  This eliminates the need to destroy
 218      * and create new buffers when different transfer directions are needed.
 219      */
 220     virtual void setDirection(IODirection direction);
 221
 222     /*
 223      * getCapacity:
 224      *
 225      * Get the buffer capacity
 226      */
 227     virtual vm_size_t getCapacity() const;
 228
 229     /*
 230      * getBytesNoCopy:
 231      *
 232      * Return the virtual address of the beginning of the buffer
 233      */
 234     virtual void *getBytesNoCopy();
 235
 236     /*
 237      * getBytesNoCopy:
 238      *
 239      * Return the virtual address of an offset from the beginning of the buffer
 240      */
 241     virtual void *getBytesNoCopy(vm_size_t start, vm_size_t withLength);
 242
 243     /*
 244      * appendBytes:
 245      *
 246      * Add some data to the end of the buffer.  This method automatically
 247      * maintains the memory descriptor buffer length.  Note that appendBytes
 248      * will not copy past the end of the memory descriptor's current capacity.
 249      */
 250     virtual bool appendBytes(const void *bytes, vm_size_t withLength);
 251 };
 252
 253 #endif /* !_IOBUFFERMEMORYDESCRIPTOR_H */