3 * Copyright (c) 2009, Microsoft Corporation.
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.
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
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.
19 * Haiyang Zhang <haiyangz@microsoft.com>
20 * Hank Janssen <hjanssen@microsoft.com>
21 * K. Y. Srinivasan <kys@microsoft.com>
26 #ifndef _RING_BUFFER_H_
27 #define _RING_BUFFER_H_
29 #include <linux/scatterlist.h>
31 struct hv_ring_buffer {
32 /* Offset in bytes from the start of ring data below */
33 volatile u32 write_index;
35 /* Offset in bytes from the start of ring data below */
36 volatile u32 read_index;
38 volatile u32 interrupt_mask;
40 /* Pad it to PAGE_SIZE so that data starts on page boundary */
44 * The interrupt_mask field is used only for channels but since our
45 * vmbus connection also uses this data structure and its data starts
46 * here, we commented out this field.
48 /* volatile u32 InterruptMask; */
51 * Ring data starts here + RingDataStartOffset
52 * !!! DO NOT place any fields below this !!!
57 struct hv_ring_buffer_info {
58 struct hv_ring_buffer *ring_buffer;
59 u32 ring_size; /* Include the shared header */
62 u32 ring_datasize; /* < ring_size */
63 u32 ring_data_startoffset;
66 struct hv_ring_buffer_debug_info {
67 u32 current_interrupt_mask;
68 u32 current_read_index;
69 u32 current_write_index;
70 u32 bytes_avail_toread;
71 u32 bytes_avail_towrite;
79 int hv_ringbuffer_init(struct hv_ring_buffer_info *ring_info, void *buffer,
82 void hv_ringbuffer_cleanup(struct hv_ring_buffer_info *ring_info);
84 int hv_ringbuffer_write(struct hv_ring_buffer_info *ring_info,
85 struct scatterlist *sglist,
88 int hv_ringbuffer_peek(struct hv_ring_buffer_info *ring_info, void *buffer,
91 int ringbuffer_read(struct hv_ring_buffer_info *ring_info,
96 u32 get_ringbuffer_interrupt_mask(struct hv_ring_buffer_info *ring_info);
98 void dump_ring_info(struct hv_ring_buffer_info *ring_info, char *prefix);
100 void ringbuffer_get_debuginfo(struct hv_ring_buffer_info *ring_info,
101 struct hv_ring_buffer_debug_info *debug_info);
103 #endif /* _RING_BUFFER_H_ */