Staging: hv: rename Connection.c to connection.c
[linux-2.6.git] / 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 <linux/scatterlist.h>
29
30 typedef struct _RING_BUFFER {
31         /* Offset in bytes from the start of ring data below */
32         volatile u32 WriteIndex;
33
34         /* Offset in bytes from the start of ring data below */
35         volatile u32 ReadIndex;
36
37         volatile u32 InterruptMask;
38
39         /* Pad it to PAGE_SIZE so that data starts on page boundary */
40         u8      Reserved[4084];
41
42         /* NOTE:
43          * The InterruptMask field is used only for channels but since our
44          * vmbus connection also uses this data structure and its data starts
45          * here, we commented out this field.
46          */
47         /* volatile u32 InterruptMask; */
48
49         /*
50          * Ring data starts here + RingDataStartOffset
51          * !!! DO NOT place any fields below this !!!
52          */
53         u8 Buffer[0];
54 } __attribute__((packed)) RING_BUFFER;
55
56 typedef struct _RING_BUFFER_INFO {
57         RING_BUFFER *RingBuffer;
58         u32 RingSize;                   /* Include the shared header */
59         spinlock_t ring_lock;
60
61         u32 RingDataSize;               /* < ringSize */
62         u32 RingDataStartOffset;
63
64 } RING_BUFFER_INFO;
65
66 typedef struct _RING_BUFFER_DEBUG_INFO {
67         u32 CurrentInterruptMask;
68         u32 CurrentReadIndex;
69         u32 CurrentWriteIndex;
70         u32 BytesAvailToRead;
71         u32 BytesAvailToWrite;
72 } RING_BUFFER_DEBUG_INFO;
73
74
75
76 /* Interface */
77
78
79 int RingBufferInit(RING_BUFFER_INFO *RingInfo, void *Buffer, u32 BufferLen);
80
81 void RingBufferCleanup(RING_BUFFER_INFO *RingInfo);
82
83 int RingBufferWrite(RING_BUFFER_INFO *RingInfo,
84                     struct scatterlist *sglist,
85                     u32 sgcount);
86
87 int RingBufferPeek(RING_BUFFER_INFO *RingInfo, void *Buffer, u32 BufferLen);
88
89 int RingBufferRead(RING_BUFFER_INFO *RingInfo,
90                    void *Buffer,
91                    u32 BufferLen,
92                    u32 Offset);
93
94 u32 GetRingBufferInterruptMask(RING_BUFFER_INFO *RingInfo);
95
96 void DumpRingInfo(RING_BUFFER_INFO *RingInfo, char *Prefix);
97
98 void RingBufferGetDebugInfo(RING_BUFFER_INFO *RingInfo,
99                             RING_BUFFER_DEBUG_INFO *DebugInfo);
100
101 #endif /* _RING_BUFFER_H_ */