drivers/staging/hv/RingBuffer.h

   1 /*
   2  *
   3  * Copyright (c) 2009, Microsoft Corporation.
   4  *
   5  * This program is free software; you can redistribute it and/or modify it
   6  * under the terms and conditions of the GNU General Public License,
   7  * version 2, as published by the Free Software Foundation.
   8  *
   9  * This program is distributed in the hope it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  12  * more details.
  13  *
  14  * You should have received a copy of the GNU General Public License along with
  15  * this program; if not, write to the Free Software Foundation, Inc., 59 Temple
  16  * Place - Suite 330, Boston, MA 02111-1307 USA.
  17  *
  18  * Authors:
  19  *   Haiyang Zhang <haiyangz@microsoft.com>
  20  *   Hank Janssen  <hjanssen@microsoft.com>
  21  *
  22  */
  23
  24
  25 #ifndef _RING_BUFFER_H_
  26 #define _RING_BUFFER_H_
  27
  28 #include "include/osd.h"
  29
  30 typedef struct _SG_BUFFER_LIST {
  31         void *  Data;
  32         UINT32  Length;
  33 } SG_BUFFER_LIST;
  34
  35 typedef struct _RING_BUFFER {
  36     volatile UINT32     WriteIndex;     // Offset in bytes from the start of ring data below
  37     volatile UINT32     ReadIndex;      // Offset in bytes from the start of ring data below
  38
  39         volatile UINT32 InterruptMask;
  40         u8      Reserved[4084];                 // Pad it to PAGE_SIZE so that data starts on page boundary
  41         // NOTE: The InterruptMask field is used only for channels but since our vmbus connection
  42         // also uses this data structure and its data starts here, we commented out this field.
  43         // volatile UINT32 InterruptMask;
  44         // Ring data starts here + RingDataStartOffset !!! DO NOT place any fields below this !!!
  45     u8          Buffer[0];
  46 } STRUCT_PACKED RING_BUFFER;
  47
  48 typedef struct _RING_BUFFER_INFO {
  49     RING_BUFFER*        RingBuffer;
  50     UINT32                      RingSize;                       // Include the shared header
  51         HANDLE                  RingLock;
  52
  53     UINT32                      RingDataSize;           // < ringSize
  54         UINT32                  RingDataStartOffset;
  55
  56 } RING_BUFFER_INFO;
  57
  58
  59 typedef struct _RING_BUFFER_DEBUG_INFO {
  60         UINT32          CurrentInterruptMask;
  61         UINT32          CurrentReadIndex;
  62         UINT32          CurrentWriteIndex;
  63         UINT32          BytesAvailToRead;
  64         UINT32          BytesAvailToWrite;
  65 }RING_BUFFER_DEBUG_INFO;
  66
  67
  68 //
  69 // Interface
  70 //
  71
  72 static int
  73 RingBufferInit(
  74         RING_BUFFER_INFO        *RingInfo,
  75         void *                          Buffer,
  76         UINT32                          BufferLen
  77         );
  78
  79 static void
  80 RingBufferCleanup(
  81         RING_BUFFER_INFO        *RingInfo
  82         );
  83
  84 static int
  85 RingBufferWrite(
  86         RING_BUFFER_INFO        *RingInfo,
  87         SG_BUFFER_LIST          SgBuffers[],
  88         UINT32                          SgBufferCount
  89         );
  90
  91 static int
  92 RingBufferPeek(
  93         RING_BUFFER_INFO        *RingInfo,
  94         void *                          Buffer,
  95         UINT32                          BufferLen
  96         );
  97
  98 static int
  99 RingBufferRead(
 100         RING_BUFFER_INFO        *RingInfo,
 101         void *                          Buffer,
 102         UINT32                          BufferLen,
 103         UINT32                          Offset
 104         );
 105
 106 static UINT32
 107 GetRingBufferInterruptMask(
 108         RING_BUFFER_INFO *RingInfo
 109         );
 110
 111 static void
 112 DumpRingInfo(
 113         RING_BUFFER_INFO* RingInfo,
 114         char *Prefix
 115         );
 116
 117 static void
 118 RingBufferGetDebugInfo(
 119         RING_BUFFER_INFO                *RingInfo,
 120         RING_BUFFER_DEBUG_INFO  *DebugInfo
 121         );
 122
 123 #endif // _RING_BUFFER_H_