release/src-rt-6.x.4708/linux/linux-2.6.36/drivers/staging/memrar/memrar-abi

   1 What:           /dev/memrar
   2 Date:           March 2010
   3 KernelVersion:  2.6.34
   4 Contact:        Eugene Epshteyn <eugene.epshteyn@intel.com>
   5 Description:    The Intel Moorestown Restricted Access Region (RAR)
   6                 Handler driver exposes an ioctl() based interface that
   7                 allows a user to reserve and release blocks of RAR
   8                 memory.
   9
  10                 Note:  A sysfs based one was not appropriate for the
  11                 RAR handler's usage model.
  12
  13                 =========================================================
  14                                 ioctl() Requests
  15                 =========================================================
  16                 RAR_HANDLER_RESERVE
  17                 -------------------
  18                 Description:    Reserve RAR block.
  19                 Type:           struct RAR_block_info
  20                 Direction:      in/out
  21                 Errors:         EINVAL (invalid RAR type or size)
  22                                 ENOMEM (not enough RAR memory)
  23
  24                 RAR_HANDLER_STAT
  25                 ----------------
  26                 Description:    Get RAR statistics.
  27                 Type:           struct RAR_stat
  28                 Direction:      in/out
  29                 Errors:         EINVAL (invalid RAR type)
  30
  31                 RAR_HANDLER_RELEASE
  32                 -------------------
  33                 Description:    Release previously reserved RAR block.
  34                 Type:           32 bit unsigned integer
  35                                 (e.g. uint32_t), i.e the RAR "handle".
  36                 Direction:      in
  37                 Errors:         EINVAL (invalid RAR handle)
  38
  39
  40                 =========================================================
  41                         ioctl() Request Parameter Types
  42                 =========================================================
  43                 The structures referred to above are defined as
  44                 follows:
  45
  46                 /**
  47                  * struct RAR_block_info - user space struct that
  48                  *                         describes RAR buffer
  49                  * @type:       Type of RAR memory (e.g.,
  50                  *              RAR_TYPE_VIDEO or RAR_TYPE_AUDIO) [in]
  51                  * @size:       Requested size of a block in bytes to
  52                  *              be reserved in RAR. [in]
  53                  * @handle:     Handle that can be used to refer to
  54                  *              reserved block. [out]
  55                  *
  56                  * This is the basic structure exposed to the user
  57                  * space that describes a given RAR buffer.  It used
  58                  * as the parameter for the RAR_HANDLER_RESERVE ioctl.
  59                  * The buffer's underlying bus address is not exposed
  60                  * to the user.  User space code refers to the buffer
  61                  * entirely by "handle".
  62                  */
  63                 struct RAR_block_info {
  64                         __u32 type;
  65                         __u32 size;
  66                         __u32 handle;
  67                 };
  68
  69                 /**
  70                  * struct RAR_stat - RAR statistics structure
  71                  * @type:               Type of RAR memory (e.g.,
  72                  *                      RAR_TYPE_VIDEO or
  73                  *                      RAR_TYPE_AUDIO) [in]
  74                  * @capacity:           Total size of RAR memory
  75                  *                      region. [out]
  76                  * @largest_block_size: Size of the largest reservable
  77                  *                      block. [out]
  78                  *
  79                  * This structure is used for RAR_HANDLER_STAT ioctl.
  80                  */
  81                 struct RAR_stat {
  82                         __u32 type;
  83                         __u32 capacity;
  84                         __u32 largest_block_size;
  85                 };
  86
  87                 Lastly, the RAR_HANDLER_RELEASE ioctl expects a
  88                 "handle" to the RAR block of memory.  It is a 32 bit
  89                 unsigned integer.