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     kIOMemorySharingTypeMask            = 0x000f0000,
  31     kIOMemoryUnshared                   = 0x00000000,
  32     kIOMemoryKernelUserShared           = 0x00010000
  33 };
  34
  35 #define _IOBUFFERMEMORYDESCRIPTOR_INTASKWITHOPTIONS_    1
  36
  37 class IOBufferMemoryDescriptor : public IOGeneralMemoryDescriptor
  38 {
  39     OSDeclareDefaultStructors(IOBufferMemoryDescriptor);
  40
  41 protected:
  42 /*! @struct ExpansionData
  43     @discussion This structure will be used to expand the capablilties of this class in the future.
  44     */
  45     struct ExpansionData {
  46         vm_map_t        map;
  47     };
  48
  49 /*! @var reserved
  50     Reserved for future use.  (Internal use only)  */
  51     ExpansionData * reserved;
  52
  53 protected:
  54     void *               _buffer;
  55     vm_size_t            _capacity;
  56     vm_offset_t          _alignment;
  57     IOOptionBits         _options;
  58     IOPhysicalAddress *  _physAddrs;
  59     unsigned             _physSegCount;
  60
  61 private:
  62     virtual bool initWithOptions(
  63                                IOOptionBits options,
  64                                vm_size_t    capacity,
  65                                vm_offset_t  alignment,
  66                                task_t       inTask);
  67
  68     OSMetaClassDeclareReservedUsed(IOBufferMemoryDescriptor, 0);
  69     OSMetaClassDeclareReservedUnused(IOBufferMemoryDescriptor, 1);
  70     OSMetaClassDeclareReservedUnused(IOBufferMemoryDescriptor, 2);
  71     OSMetaClassDeclareReservedUnused(IOBufferMemoryDescriptor, 3);
  72     OSMetaClassDeclareReservedUnused(IOBufferMemoryDescriptor, 4);
  73     OSMetaClassDeclareReservedUnused(IOBufferMemoryDescriptor, 5);
  74     OSMetaClassDeclareReservedUnused(IOBufferMemoryDescriptor, 6);
  75     OSMetaClassDeclareReservedUnused(IOBufferMemoryDescriptor, 7);
  76     OSMetaClassDeclareReservedUnused(IOBufferMemoryDescriptor, 8);
  77     OSMetaClassDeclareReservedUnused(IOBufferMemoryDescriptor, 9);
  78     OSMetaClassDeclareReservedUnused(IOBufferMemoryDescriptor, 10);
  79     OSMetaClassDeclareReservedUnused(IOBufferMemoryDescriptor, 11);
  80     OSMetaClassDeclareReservedUnused(IOBufferMemoryDescriptor, 12);
  81     OSMetaClassDeclareReservedUnused(IOBufferMemoryDescriptor, 13);
  82     OSMetaClassDeclareReservedUnused(IOBufferMemoryDescriptor, 14);
  83     OSMetaClassDeclareReservedUnused(IOBufferMemoryDescriptor, 15);
  84
  85 protected:
  86     virtual void free();
  87
  88     virtual bool initWithAddress( void *      address,       /* not supported */
  89                                   IOByteCount withLength,
  90                                   IODirection withDirection );
  91
  92     virtual bool initWithAddress( vm_address_t address,      /* not supported */
  93                                   IOByteCount  withLength,
  94                                   IODirection  withDirection,
  95                                   task_t       withTask );
  96
  97     virtual bool initWithPhysicalAddress(
  98                                   IOPhysicalAddress address, /* not supported */
  99                                   IOByteCount       withLength,
 100                                   IODirection       withDirection );
 101
 102     virtual bool initWithPhysicalRanges(
 103                                   IOPhysicalRange * ranges,  /* not supported */
 104                                   UInt32            withCount,
 105                                   IODirection       withDirection,
 106                                   bool              asReference = false );
 107
 108     virtual bool initWithRanges(  IOVirtualRange * ranges,   /* not supported */
 109                                   UInt32           withCount,
 110                                   IODirection      withDirection,
 111                                   task_t           withTask,
 112                                   bool             asReference = false );
 113
 114     IOGeneralMemoryDescriptor::withAddress;                  /* not supported */
 115     IOGeneralMemoryDescriptor::withPhysicalAddress;          /* not supported */
 116     IOGeneralMemoryDescriptor::withPhysicalRanges;           /* not supported */
 117     IOGeneralMemoryDescriptor::withRanges;                   /* not supported */
 118     IOGeneralMemoryDescriptor::withSubRange;                 /* not supported */
 119
 120 public:
 121
 122     /*
 123      * withOptions:
 124      *
 125      * Returns a new IOBufferMemoryDescriptor with a buffer large enough to
 126      * hold capacity bytes.  The descriptor's length is initially set to the
 127      * capacity.
 128      */
 129     virtual bool initWithOptions(   IOOptionBits options,
 130                                     vm_size_t    capacity,
 131                                     vm_offset_t  alignment);
 132
 133     static IOBufferMemoryDescriptor * withOptions(  IOOptionBits options,
 134                                                     vm_size_t    capacity,
 135                                                     vm_offset_t  alignment = 1);
 136
 137 /*! @function inTaskWithOptions
 138     @abstract Create a memory buffer with memory descriptor for that buffer. Added in Mac OS X 10.2.
 139     @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.
 140     @param inTask The task the buffer will be allocated in.
 141     @param options Options for the allocation:
 142     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.
 143     kIOMemoryPageable - pass to request memory be non-wired - the default for kernel allocated memory is wired.
 144     kIOMemoryKernelUserShared - pass to request memory that will be mapped into both the kernel and client applications.
 145     @param capacity The number of bytes to allocate.
 146     @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.
 147     @result An instance of class IOBufferMemoryDescriptor. To be released by the caller, which will free the memory desriptor and associated buffer. */
 148
 149     static IOBufferMemoryDescriptor * inTaskWithOptions(
 150                                             task_t       inTask,
 151                                             IOOptionBits options,
 152                                             vm_size_t    capacity,
 153                                             vm_offset_t  alignment = 1);
 154
 155     /*
 156      * withCapacity:
 157      *
 158      * Returns a new IOBufferMemoryDescriptor with a buffer large enough to
 159      * hold capacity bytes.  The descriptor's length is initially set to the
 160      * capacity.
 161      */
 162     static IOBufferMemoryDescriptor * withCapacity(
 163                                      vm_size_t    capacity,
 164                                      IODirection  withDirection,
 165                                      bool         withContiguousMemory = false);
 166     /*
 167      * initWithBytes:
 168      *
 169      * Initialize a new IOBufferMemoryDescriptor preloaded with bytes (copied).
 170      * The descriptor's length and capacity are set to the input buffer's size.
 171      */
 172     virtual bool initWithBytes(const void * bytes,
 173                                vm_size_t    withLength,
 174                                IODirection  withDirection,
 175                                bool         withContiguousMemory = false);
 176
 177     /*
 178      * withBytes:
 179      *
 180      * Returns a new IOBufferMemoryDescriptor preloaded with bytes (copied).
 181      * The descriptor's length and capacity are set to the input buffer's size.
 182      */
 183     static IOBufferMemoryDescriptor * withBytes(
 184                                      const void * bytes,
 185                                      vm_size_t    withLength,
 186                                      IODirection  withDirection,
 187                                      bool         withContiguousMemory = false);
 188
 189     /*
 190      * setLength:
 191      *
 192      * Change the buffer length of the memory descriptor.  When a new buffer
 193      * is created, the initial length of the buffer is set to be the same as
 194      * the capacity.  The length can be adjusted via setLength for a shorter
 195      * transfer (there is no need to create more buffer descriptors when you
 196      * can reuse an existing one, even for different transfer sizes).   Note
 197      * that the specified length must not exceed the capacity of the buffer.
 198      */
 199     virtual void setLength(vm_size_t length);
 200
 201     /*
 202      * setDirection:
 203      *
 204      * Change the direction of the transfer.  This method allows one to redirect
 205      * the descriptor's transfer direction.  This eliminates the need to destroy
 206      * and create new buffers when different transfer directions are needed.
 207      */
 208     virtual void setDirection(IODirection direction);
 209
 210     /*
 211      * getCapacity:
 212      *
 213      * Get the buffer capacity
 214      */
 215     virtual vm_size_t getCapacity() const;
 216
 217     /*
 218      * getBytesNoCopy:
 219      *
 220      * Return the virtual address of the beginning of the buffer
 221      */
 222     virtual void *getBytesNoCopy();
 223
 224     /*
 225      * getBytesNoCopy:
 226      *
 227      * Return the virtual address of an offset from the beginning of the buffer
 228      */
 229     virtual void *getBytesNoCopy(vm_size_t start, vm_size_t withLength);
 230
 231     /*
 232      * appendBytes:
 233      *
 234      * Add some data to the end of the buffer.  This method automatically
 235      * maintains the memory descriptor buffer length.  Note that appendBytes
 236      * will not copy past the end of the memory descriptor's current capacity.
 237      */
 238     virtual bool appendBytes(const void *bytes, vm_size_t withLength);
 239 };
 240
 241 #endif /* !_IOBUFFERMEMORYDESCRIPTOR_H */